WO2010053381A1

WO2010053381A1 - Pyrolytic rendering of organic material

Info

Publication number: WO2010053381A1
Application number: PCT/NZ2009/000238
Authority: WO
Inventors: Christopher Francis Newman; Hamish William Hamilton; Roger John Monckton
Original assignee: Christopher Francis Newman; Hamish William Hamilton; Roger John Monckton
Priority date: 2008-11-04
Filing date: 2009-11-04
Publication date: 2010-05-14
Also published as: AU2009311787A1; NZ569587A; WO2010053381A4

Abstract

Pyrolysis of vehicle tyres within vertically oriented, thermally conductive, elongated, and slightly flared pyrolysis chambers is facilitated with airlocks for each chamber, for excluding air from solids passing in or out. The gaseous pyrolysate is purified. Some is burnt within an external heating chamber. The remainder, and solid carbon may be sold. Substantially continuous operation involves cyclic operation of the airlocks and steady slumping of the material being pyrolysed. The pyrolysis equipment is constructed within a vertically oriented shipping container and a distillation column is inside a second. A gasometer is preferably used to store inflammable gases at low pressure.

Description

PYROLYTIC RENDERING OF ORGANIC MATERIAL

FIELD This invention relates to use of heat to break down organic materials in order to dispose of the materials and recover at least some commercially useful components of the organic materials. More particularly, the invention uses pyrolysis in a closed space, and the invention is applied to shredded car tyres. The apparatus may include some of the principles of coke ovens.

DEFINITIONS The term 'pyrolysis' is generally defined as the breakdown of a substance by heat into thermally stable component chemical parts, usually in a substantially oxygen-free and/or catalyst-free environment.

The term 'pyrolysate ', as used in this specification, is defined as being any product produced as a result of pyrolysis. For example, tyre pyrolysis produces liquid, gaseous and solid pyrolysate. "Anoxic" or "anaerobic" are terms referring to conditions in which oxygen is excluded; or at least is present in low concentrations only, so that feedstock may be heated without combustion occurring. By "low concentrations" we mean the oxygen is half or less that of air under standard conditions.

BACKGROUND Disposal of used or waste rubber vehicle tyres in a safe and/or environmentally acceptable manner has long presented a problem to relevant authorities. A commercially useful manner of disposal would be a bonus. Millions of waste tyres have been deposited in landfills over the years. However, tyres are not easily compactable and therefore take up a lot of landfill space. Being substantially non-biodegradable unaltered and buried. Many regulatory bodies now prohibit the disposal of whole waste tyres in landfills, because they can create voids within landfills leading to instability such as slumps. Moreover, the elasticity of tyres often causes the tyres to move within landfills, creating further site instability, and thus causing problems for any future use of landfill sites.

Storage of shredded tyres in landfills, presents its own problems, such as release of the components of the tyres (or metals), thus producing hydrocarbon based oily toxic leachates which have the potential to contaminate adjacent ground water, which is clearly undesirable. Many tyres are simply stockpiled. Stockpiles provide an ideal habitat for vermin and provide a perfect habitat for breeding mosquitoes as whole tyres trap rainwater. Stockpiles of tyres are ugly, and inflammable. If the stockpile catches fire the resultant fire may take significant cost, resources and time to extinguish. This is because stockpiled tyres are difficult to access. Tyres are capable of smouldering underneath the pile for a significant length of time. Furthermore, burning tyres release a large amount of toxic smoke and oily liquid, thereby creating major pollution and cleanup issues.

In order to address the difficulties associated with the disposal of tyres, as outlined above, a number of systems have been developed for the pyrolysis of tyres. Typical examples are described in US Patents 7329329 (Masemore et al; having an auger to move solids), 6909025 (Suominen; air jets to clean the incoming material to be pyrolysed), 6736940 (Masemore et al; for using an oil spray to trap evolved hydrocarbons), and 5167772 (Parker, for a ram system to heat then deform incoming tyres into solid plugs for pyrolysis). Some difficulties associated with the pyrolysis of tyres (or other materials) generally, and/or some. disadvantages associated with many presently known pyrolysis systems include:

1. Economical operation is required so that the process is sustainable as a business operation. A substantially "self-powered" process in which the tyres provide fuel for their own heat, yet do not release noxious materials into the atmosphere is desired; one that can be run at a profit if possible (even including acquisition of feedstock without government subsidies) by re-sale as far as possible of the chemical and physical components (pyrolysates) recovered from the process.

2. Most pyrolysis systems require the use of hot moving parts within the pyrolysis chamber such as. augurs and chain drives, and even a rotating sloping chamber. This use presents significant engineering obstacles, which we believe the prior art has not yet adequately addressed and/or which makes some prior art processes commercially prohibitive.

3. The pyrolysis of tyres is stressful to the metal surfaces within which (or adjacent to where) the pyrolysis occurs. Examples of such process wear and tear factors include: thermal cycling; the reductive environment of the pyrolysates, particularly the sulphur compounds in the pyrolysate gases; carburization of the inside of the pyrolysis apparatus; and metal fatigue from thermal expansion and contraction of the pyrolysis apparatus.

4. Many pyrolysis components of prior art systems, such as process containers or heated vessels, are relatively short and/or wide or are processed in a horizontal configuration and their design and layout does not adequately address the mechanical and chemical factors which govern the efficient transfer of heat into the pyrolysis material. Such components therefore have only modest surface to volume ratios, which causes a problem over time through the inefficient heat process transfer rates or depend on elaborate heating or pyrolysate capture systems which introduce further processing limitations.

5. Some current systems utilize electricity to power the plant's thermal process, and fail to use evolved flammable materials that may release chemical energy if burnt. The energy input has implications regarding the commercial viability of the operation as well as the overall environmental suitability of the process.

6. Some current systems rely for their effectiveness on the use of either positive or negative pressure in the pyrolysis vessel to improve the volatilisation of the pyrolysates. The increased expenses, maintenance and safety risks associated with using pressure vessels to process combustible hydrocarbon gases at pressure (either negative or positive) are a major disadvantage.

7. Some current systems process a single batch with a cool down period in between batches with waiting times, thermal cycling, and reheating to be considered. It may be more efficient and commercially viable to operate on a continuous batch basis, i.e. on a controlled infeed and outflow basis - or at the very least have this as an option.

OBJECT

It is an object of the present invention to provide an improved pyrolysis system, capable of economically converting organic matter into useful resources, which at the very least provides the public with a useful choice of an environmentally acceptable plant producing recycled resources.

STATEMENTS OF INVENTION

In a first broad aspect the invention provides a pyrolysis device for heating organic materials to an elevated temperature for a period and thereby causing thermal decomposition of organic materials; wherein the pyrolysis device is comprised of at least one vertically oriented pyrolysis chamber capable when in use of containing a process of pyrolysis; each chamber being thermally conductive, elongated, and slightly flared so as to be wider towards the base; each chamber having attached thereto an input valve means including air exclusion means, and an output valve means also including air exclusion means, and means to convey a gaseous pyrolysate through an at least partial purification means and to convey a controlled amount of the purified pyrolysate to a thermal oxidiser capable of burning the purified pyrolysate within an external heating chamber surrounding the at least one vertically oriented pyrolysis chamber. A pyrolysis device as previously described in this section, wherein the input valve means comprises a first airlock chamber; the airlock chamber having a first openable gas-tight sealing 100 means between the exterior and the airlock chamber, and a second openable gas-tight and heat- resistant sealing means after the airlock; the airlock including evacuation means capable of withdrawing air from a charge of organic material placed within the airlock and then of replacing the air with a substantially oxygen-free gas.

A pyrolysis device as previously described in this section, wherein the second heat-resistant 105 sealing means after the first airlock chamber and preceding the pyrolysis chamber includes an aperture, a closing means, and aperture surrounding means including cooling means directed to the aperture edges employing at least one cooled fluid, and seal protection means in the form of a sleeve which, when in the lowered position, protects the seals from exposure to uprising process heat.

110 A pyrolysis device as previously described in this section, wherein the pyrolysis chamber is provided with means capable of providing for over-pressure relief using alternate channels each terminated by a rupturable diaphragm.

A pyrolysis device as previously described in this section, wherein the pyrolysis device is provided with at least one compliant (meaning, that a volume of gas may be stored without 115 significant rise in pressure) gas storage means or gasometer for the storage of flammable gases

A pyrolysis device as previously described in this section, wherein the output valve of the pyrolysis chamber comprises a second airlock chamber; the airlock including a operable char withdrawal means capable when in operation of controllably removing the solid residues of pyrolysate from the pyrolysis chamber above and into the second airlock chamber; a first 120 sealing means adjacent the pyrolysis chamber and a second sealing means adjacent a solids withdrawal means.

A pyrolysis device as previously described in this section, wherein the operable char withdrawal means comprises a cylindrical mechanical device located beneath an open lower end of the at least one vertically oriented pyrolysis chamber; the withdrawal means being 125 capable of being revolved from time to time, and bearing at least one protrusion capable of engaging with solid pyrolysate and like material and of breaking apart said solid pyrolysate and causing the solid pyrolysate to fall on to a closed, horizontally retractable door of sliding valve means comprising the first openable sealing means of the second airlock chamber.

A pyrolysis device as previously described in this section, wherein the operable char 130 withdrawal means comprises a linear mechanical device located beneath an open lower end of the at least one vertically oriented pyrolysis chamber; the withdrawal means being capable of being withdrawn away from the open lower end from time to time, thereupon allowing the solid pyrolysate to fall on to a closed horizontally retractable door of sliding valve means comprising the first sealing means of the second airlock chamber.

135 A pyrolysis device as previously described in this section, wherein the solid pyrolysate is recovered from the second airlock chamber through a second openable sealing means thereof and held within an environment from which air is excluded until the solid pyrolysate has been cooled sufficiently for combustion in air to be not possible.

A pyrolysis device as previously described in this section, wherein the environment from 140 which air is excluded comprises a transport means selected from a range including a closed container, an auger operated inside a cowling, and a conveyor operated inside a cowling; said transport means being flushed with cooled flue gases obtained from the heating chamber.

A pyrolysis chamber as previously described in this section, wherein the input valve means and the output valve means are each provided with a first connecting means or pipe controlled

145 by a first valve and leading to an evacuated container, and a second pipe controlled by a second valve and leading to a source of flue gas having a low concentration of oxygen, and a third pipe controlled by a third valve and leading to a source of flammable gas having a low concentration of oxygen, so that any air initially present is substantially replaced by a gas having a low content of oxygen and so that fumes collected from the valve means are conveyed

150 into the evacuated container for disposal.

A thermal oxidiser as previously described in this section, wherein the thermal oxidiser is capable of serving to dispose of, by flaring off, unwanted flammable gases and the enclosing heating chamber is provided with temperature regulation means comprising temperature measurement means and means capable of admitting and stirring cold air within the chamber in 155 an event of excess temperature caused by a flaring event.

A pyrolysis device as previously described in this section, wherein the pyrolysis device, and the associated distillation column, are each provided inside an up-ended shipping container and thereby is modular and capable of replication for the purpose of expansion, or for the purpose of providing for maintenance.

160 In a second broad aspect the invention provides a method of operating a sealed pyrolysis device for heating organic materials to an elevated temperature for a period and thereby causing thermal decomposition of organic materials in a substantially continuous manner; wherein the method includes the steps of stepwise admission of a feedstock into the input valve means and stepwise release therefrom, after flushing free of air, of the feedstock into the 165 pyrolysis chamber which is maintained in a substantially full state; and after pyrolysis has occurred at a known temperature and for a known period of time in an air-free atmosphere, of controllably causing release of the slumped solid pyrolysate from the output valve means into a contained space, substantially free of air, for cooling and subsequent recovery.

PREFERRED EMBODIMENTS

170 The description of a preferred form of the invention to be provided herein, with reference to the accompanying drawings, is given purely by way of example and is not to be taken in any way as limiting the scope or extent of the invention. Throughout this specification, unless the text requires otherwise, the word 'comprise' and variations such as 'comprising' or 'comprises' will be understood to imply the inclusion of a stated integer or step or group of integers or steps but

175 not the exclusion of any other integer or step or group of integers or steps.

DRAWINGS

Fig 1 : is a perspective view of the invention.

Fig 2: is a partially cutaway view of an example of the gate valve situated between the hopper and the pyrolysis tube in its closed position.

180 Fig 3 : is a partially cutaway view of an example of the gate valve in its open position.

Fig 4: relates to solid detritus extraction; including a perspective view of the air lock arrangement situated at the bottom of the pyrolysis tube above the solid pyrolysate receiving chambers, single and twin " and three arrangements for bear claw and other extractor mechanisms.

185 Fig 5: is a cross sectional elevation and plan drawing of the bottom end extractor prong tines option for controlling release of solid detritus.

Fig 6: is an elevation view showing the sequence of the operation of the extractor prongs.

Fig 7: is a cross sectional view of the bottom end of the outwardly flared pyrolysis tube plus a bear claw roller extractor mechanism above an airlock comprising the solid 190 pyrolysate receiving chambers and an end view of the enclosed conveyor unit.

Fig 8: comprises perspective views of the two embodiments of the stoichiometrically variable gas burner.

Fig 9: is a simplified view showing one possible embodiment of the distillation column. Fig 10: is a schematic view showing conduits for products of the pyrolysis apparatus in place 195 about a basic vertical pyrolysis chamber.

Fig 11 : is a schematic view showing interconnections of the distillation apparatus.

Fig 12: is a simplified view showing the burst disc apparatus before (above) and after (below) a burst disc rupture event.

Fig 13: is two partially cutaway views of the bottom end plug gate valve both closed (above) 200 and open (below).

Fig 14: is a partial cutaway view showing one possible embodiment of the removable solid pyrolysate receiving chamber.

INTRODUCTION

The invention in the form described herein has been adapted for use in the pyrolysis of tyres.

205 Although the following description relates in particular to tyre pyrolysis, it shall be understood by the reader that the pyrolysis system could be utilised for the pyrolysis of any predominantly organic-based products or compounds, examples including rubber material and plastics material (especially non-chlorinated plastics), and biowastes; either separately or in a combination capable of being pyrolysed. A likely option is to dispose of some hospital waste

210 along with a major proportion of shredded vehicle tyres, comprised of rubber and steel along with some other fibres.

One feature of this apparatus is that it may be run in a batch mode, or more preferably in a semi-continuous mode in which the air locks that admit material to be cooked and expel solid residues are operated in a particular sequence while the main oven is run continuously and 215 solid material moves downward through the oven all the time.

Refer to Figs 1, 9, 10 and 11 which show a simplified schematic view of the pyrolysis apparatus 1 and the associated distillation apparatus 16. The tyre pyrolysis system is built to fit within a vertically aligned 40 foot shipping container (not shown) as a relatively cost effective process vessel. The shipping container serves as a convenient case or shroud, and a shipping

220 container, and provides a predetermined modular size for the apparatus which may be expanded as required by the addition of further substantially identical modules. Similarly the or each distillation apparatus is provided within a vertically oriented shipping container. Such containers avoid design and building of a major plant structure or building to house the overall pyrolysis system. The process containers are of unit construction, strengthened shipping

225 containers standing vertically and fastened to a strengthened concrete base. Their configuration provides an economy of site area and allows for the modular construction of the tyre pyrolysis process plant. Subframes required for sections of the plant can be readily attached to the container's members. For example heating chamber insulation can be easily fastened to the sides of the container and the pyrolysis tubes are supported by cross beams fixed in place. The 230 overall unit provides complete weather protection for its contents, the interior is adaptable for stairwells and other production applications and the exterior can be fitted to purpose, for example with an elevator.

Single containers can be fitted out elsewhere and brought on to site, then structurally linked to others for greater lateral stability. Their space saving and multi-function uses make vertical 235 containers an economic advantage over the other options. Containerised modules can be added to match the expansion of the plant's processing capacity to the processing requirements of the local waste tyre supply. All these benefits flow from the choice of the vertical shipping container for all the plant requirements.

Gravity is used as far as possible to effect flow of materials. For example the in-line vertical 240 descent of the tyres through the pyrolysis tube brings them into contact with the vertical rise of hot pyrolysate gases as they ascend to exit the tube through the manifold. So the departing hot gases impart some of their heat to pre-warm the descending tyres and thereby accelerate the release of volatile materials.

This vertical arrangement also overcomes the requirement for expensive and high maintenance 245 mechanical equipment which otherwise would be needed to move the material through the hot system. The heat stresses to the steel vessels as they hang vertically are taken out in longitudinal tension and compression movement rather than the more destructive bending seen in horizontal heat plants. This extends the life of the equipment.

By fitting the pyrolysis tube with a slight outward descending flare the processing tyres are

250 free to descend with no risk of -grabbing" on the tube's wall, so enhancing the vertical effect of movement under gravity. The vertical in-line arrangement of tubes allows for an effective array of multiple pyrolysis tubes in one heating chamber. At the discharge end, the use of gravity also allows for a simplified release through the gas tight chamber section. The net result is considerable savings by not having to move char/wire mechanically through the pyrolyser and

255 by fitting multiple tubes in the heat chamber the most effective and economical use of the heating process and energy inputs is achieved.

The vertical arrangement also reduces the plant's footprint which lessens the expense of the real estate. 260 Fig 1 : shows pyrolysis apparatus, generally indicated by arrow 1. Each pyrolysing module 1 is provided with typically two loading hoppers 2a, 2b. Two vertically aligned pyrolysis tubes 3 a, 3b (here shown in dotted outline) are housed within and heated by a heating chamber 4. A thermal oxidiser incorporating the heat source is generally indicated by arrow 10, and two solid pyrolysate receiving chambers are shown below as 6a, 6b.

265 There is a loading hopper 2 for receiving a feedstock of tyres or parts of tyres; preferably shredded tyres initially from a feedstock loading bin (not shown).

For the exclusion of oxygen as described elsewhere, a vacuum pump 54 as shown in Fig. 10 is used for evacuating the hopper 2, via pipes 55. Pipe 56 is used to evacuate the solid pyrolysate receiving chamber 6 b in a similar way, so that oxygen cannot reach hot and inflammable solid 270 pyrolysate.

A sealable opening or "gate valve" 27a, 27b, and 27c is used as an airlock capable of admitting feedstock into the pyrolysis tube from time to time. Otherwise the pyrolysis tube 3 is sealed off from the loading hopper 2. The gate valve region 27 is preferably cooled using water jackets 26, partly as a fumes control measure. Pipes 58 circulate cooling water.

275 From one to perhaps four pyrolysis tubes, (but only two: 3a, 3b are shown here) below the loading hopper 2 are each fitted with an outlet pipe 68 for the release of gaseous pyrolysates and housed within a heated chamber 4. The related thermal oxidiser 10 is shown schematically in Fig 8 as its constituent parts, including a diesel start-up burner 64, a stoichiometrically variable main burner 120, a concrete refractory castable fire box 47 and residence chamber 11,

280 with a duct 12 taking the resultant gases into the heating chamber 4, thus providing the pyrolysis heat. The stirrer fan(s) 14a, 14b used in this chamber mix the hot gases for temperature regulation, and thereby manage the pyrolysis temperature. The main burner 120 is provided with locally obtained gas input from the main gas line 67 which connects the gasometer 73 to the distillation column 16 and the burner 50 has a side line for fumes input 66

285 from the vacuum ballast tank 72.

Either a further sealable plug door 142 or continuous extraction mechanism 107, 108, 109, 116, 117 for the release of solid pyrolysates from the bottom of the pyrolysis tube 3 into the receiving chamber 6 a, 6b, 6c or 136, upon completion of the pyrolysis cycle is fitted at the bottom of the tube 3,

290 A solid pyrolysate receiving chamber collects solid pyrolysates such as char and steel wire, said receiving chamber being either fixed items 6 a, 6b, 6c or moveable (disconnectable) chamber 136 and is situated below the extraction system 107, 108, 109, 116, 117 and below the pyrolysis tube/chamber 3. The water for the water jacket 118, 119, 137 surrounding the solid pyrolysate receiving 295 chamber 6, and for the water jackets in the region between the pyrolysis tube 3 and bottom receiving chamber 6, is provided via the piping 63.

The distillation apparatus 16 (see for instance fig 10) is formed so as to fit within a vertically aligned 40 foot shipping container (not shown), and is provided with a number of platforms 21 and stairwells 22 for operator access.

300 Automatic controls such as a computerised system with sensors and programmed logic modules are preferred for monitoring, recording, and managing the pyrolysis process, since the alternative; human operators, are more expensive.

The tyre feedstock will, if raised to a suitable temperature, evolve sufficient combustible gases to effect its own pyrolysis, although there may be instances where the commercial value of

305 disposing of some other feedstock material justifies the burning of externally supplied fuel. Any process such as this depends on the various costs of operation and replacement, the cost of incoming materials, and the possibility of selling recovered solid, liquid, or energy-rich gaseous residues in order to cover the costs of operation. In effect, the invention is capable of causing the thermal decomposition of a material to be disposed of, pyrolysing the material

310 under conditions in which the material is heated in an anoxic environment and completely recovering the resources of the material for reuse.

In this preferred embodiment of pyrolysis apparatus, it is convenient and preferable to use an elongated upright pyrolysis chamber 3 since heat rises and residues fall, and the interior of the working pyrolysis chamber is inherently hostile to movable apparatus which would be likely to 315 be required if a sloping or horizontal pyrolysis chamber was used, whether fixed or slowly rotating or requiring some mechanical method of moving the feedstock through the heating process. An upright arrangement has a smaller site requirement than competing systems.

The prototype equipment as described can be operated as a batch process or as a semi- continuous system. The loading hopper 2 operates on a cycle; the heating chamber 4 remains 320 hot, and the solids extraction mechanism operates in one configuration as a batch release 142, and in another configuration, see choices 107, 108, 109, 116, 117, as a continuous output. Means for "hot loading" and for emptying the hot processed materials from the pyrolysis chamber 3 avoid the demands of repeated heating and cooling which takes time, imposes thermal cycling on apparatus, and is simply uneconomic in many instances.

325 Aspects of the equipment shall now be described in detail.

FEEDSTOCK MATERIALS The feedstock used for the prototype example may, without limitation, include used tyres which are the particular subject of this application. Tyres include rubber, nylon or other fibres materials, and steel wire. Preferably the tyres will have been shredded or granulated to a

330 suitable size before reaching the loading hopper such as by use of counter-rotating tyre shredding machinery as used by (for example) J & J Laughton Tyre Shredding Services, of Auckland, New Zealand. The existing plant arrangement can be adapted to function as either a batch process with large ungraded first shred feedstock or as a semi-continuous throughput process using tyre shred feed stock smaller than 100 mm maximum diameter. Both types of

335 feedstock may be fed into the top infeed hopper. Whole tyres may be used without shredding as a feedstock. Alternatively, whole tyres may be slit in half (for example, by a rotating knife or guillotine) to produce two 'C shaped halves, or into 4, 6, or 8 segments.

By way of variation, it is possible to mix a controlled amount of feedstocks for example; plastics waste, bio-waste, bio-hazardous waste or the like with the tyres since the pyrolysis 340 procedure will take care of most potential biohazards.

FEEDSTOCK CARRIAGE

The feedstock, as previously described, is placed in a large bin, (not shown) which is raised by the use of a suitable hoisting means dependent for instance on beam 80 (see Fig 1 and placed on the work platform 100. The feedstock is then moved into the top openings 8a, 8b of the 345 hoppers 2a, 2b. This may be done manually by a worker stationed on the platform 7, reached by an adjacent stairwell (not shown), or by mechanical means.

The loading hoppers 2a, 2b have an airlock configuration so that an outer sliding or hinged lid 101 can be opened for addition of feedstock only when the inner sealable opening ( fig 2, 37) is closed, so that oxygen is excluded from hot feedstock. Preferably each lid is made sufficiently 350 strong in order to withstand an internal vacuum (see "air exclusion process" later). This may also be a requirement imposed by emission control legislation. If a person were to be used to assist with the loading procedure, there is a risk that person may be exposed to or overcome by heat and fumes during the procedure, so automated loading involving a controlled sequence of closing and opening the apparatus is preferred in a well ventilated work environment.

355 Also shown in Fig 1 is the thermal oxidiser 10, including a residence chamber 11 and a duct 12 which passes into the heating chamber 4 and carries hot gases to heat the heating chamber 4 which surrounds the pyrolysis tubes 3. The residence chamber 11 acts as a thermal oxidiser which in this case allows for a residence time of at least 0.75 seconds for the complete oxidation of any sulphur compounds in the fuel gas. 360 The heating chamber 4 can be provided with an air inlet 13, into which outside cool air can be pumped to regulate the temperature inside the heating chamber 4. Preferably, the temperature inside the heating chamber 4 is maintained at approximately 500° to 600° Celsius. The temperature within the heating chamber 4 is also maintained and/or regulated by the use of stirring fans 14a, 14b, which also serve to ensure the temperature is substantially even

365 throughout the entire heating chamber 4. These fans are supported through the wall of the chamber 4 by the fan fixtures 14a, 14b.

An exhaust flue 15 is raised from the chamber 4 to a point well above the loading hoppers 2a,b. This exhaust flue 15 allows for the release of waste gases and heat from the chamber 4 at a point approximately 4m above the top 80 of the pyrolysis apparatus 1.

370 MATERIALS

Fig 1 : In order to minimise the total capital cost, materials selection is of importance. The hoppers 2a, 2b and pyrolysis tubes 3 a, 3b, heating chamber 4, and solid pyrolysate receiving chamber 6a, 6b, 6c, or 136 are all made from 6 mm mild steel. The exhaust flue 15 is made of stainless steel. The insides of the hoppers 2a, 2b, pyrolysis tubes 3 a, 3b, and solid pyrolysate 375 receiving chambers 6a,b are not lined as there are no significant corrosive forces there.

The residence chamber 11 and the duct 12 are made entirely from "Kaowool" (Forman Group, New Zealand) and the inside is lined with ITC 296A (International Technical Ceramics, FL, USA). This lining protects the Kaowool from the corrosive effects of the hot gases and provides additional insulation effect over that provided by the Kaowool. On the outside of the 380 Kaowool duct 12 there may be provided an expanded steel mesh to support the Kaowool and give it better form and rigidity.

The inside of the heating chamber 4 is lined with Kaowool. The Kaowool is also lightly sprayed with a rigidiser film to protect it from erosion by excessive gas flow. The Kaowool inside the heating chamber 4 is supported from behind by long stainless steel pins mounted on

385 brackets (not shown), which in turn are fixed to the exterior walls of the chamber 4. The inner face of the Kaowool is secured against the stainless steel pins by large ceramic washers or tabs. The mounting of the Kaowool on these pins leaves a gap (approximately 100mm) between the Kaowool and the mild steel exterior walls around the chamber 4. Into this gap is poured Vermiculite (Nuplex, New Zealand) which has superlative insulative properties. The crumbly

390 Vermiculite is supported in place by a layer of expanded steel mesh, similar to chicken wire, or by Kaowool suitably arranged as a laminate layer. Reflective metal foil can also be used to further improve the insulation properties of the material surrounding the heating chamber 4. The floor of the chamber 4 is simply poured Vermiculite to a depth of approximately 50 N 70 mm. The vermiculite on the floor of the chamber 4 can further be covered with a blanket of 395 Kaowool. Preferably, the heating chamber 4 may be provided with an access port (not shown) for maintenance when not hot, for example a manhole formed in the bottom or side of the chamber.

International Technical Ceramics produce a proprietary range of metal protective products. Various ITC products were Mailed as coatings for the outside of the mild steel pyrolysis tube.

400 One of their products (ITC Product No. ITC 213) produces a ceramo-metallic bond and appears capable of protecting a mild steel surface from both oxidising gases (sulphur dioxide) and the effects of thermocycling. ITC Product No. ITC 296A is used as a coating on the inner surface of the Kaowool ducting, immediately above the combustion chamber of the heat source, thereby preventing the erosion of the kaowool surface, stiffening the structure and

405 enhancing the thermal efficiency of that unit.

Should there prove to be any long term difficulties with metal erosion despite the ITC products, other options would be electroplated coating of corrosion resistant metal, or to shield the inner surface of the mild steel pyrolysis tube with an optionally coated outer layer of stainless steel foil, thin enough to conduct heat, and preferably with a gas envelope between 410 these two materials filled with helium. Helium has a suitable thermal conductivity, is chemically inert, relatively cheap and would protect the inner surface of the mild steel pyrolysis tube.

AIR EXCLUSION PROCESS

The object is to lower the level of oxygen as far as possible from the feedstock environment to 415 eliminate any risk of combustion, before it is admitted into the pyrolysis chamber which contain combustible gases. See Fig 2, Fig 3, and Fig 10.

When the plant is first started from cold the bottom seals are closed at the receiving chamber 6 b. The top of the infeed hopper 2 is opened and the entire cavities of the pyrolysis tubes and all related vessels are flooded with an inert gas. Usually carbon dioxide is used at this time 420 because it is heavier than air and displaces the air in the vessels. An oxygen sensor positioned at the top if the infeed hopper indicates when the level of oxygen throughout the system present reaches an acceptable level which is around 5% or less. At this stage the carbon dioxide purge is concluded, the top gate valve assembly 27 closed and the top infeed hopper 2 is prepared for loading.

425 A three-step process is currently favoured to remove oxygen from the environment of the ingoing tyre pieces and hence within the pyrolysis chamber, to ensure a safe loading procedure into the hot pyrolysis tube. First a vacuum is applied to the closed, filled hopper 2 to drop the oxygen content to below 5%. Then the hopper 2 is flushed with flue gas at substantially atmospheric pressure, which is then removed by vacuum. Finally non-condensable fuel gas is 430 admitted to the hopper at substantially atmospheric pressure.

In use, the feedstock is placed into the hopper 2. The hopper lid 101 is then closed and sealed and the hopper 2 is purged of air by a vacuum pump 54 through vacuum line 55 to drop the oxygen content to below 5%. Exhaust gas depleted in oxygen and recovered from the bottom of the exhaust flue 15 is then pumped through a line (not shown) into the hopper 2 and this is 435 also purged out by the vacuum pump 54. Lastly, fuel gas recovered from the main gas pipe 67 located after the distillation apparatus 16 which is in line with the gasometer supply is piped in not shown) and again purged. These flushing and purging steps may be repeated as many times as considered necessary, with the aim being to reduce oxygen content within the hopper 2 to an anoxic condition and prepare the feedstock for safe entry into the pyrolysis tube 3.

440 The use of a vacuum extraction technique for both ends of the oven - the tyre infeed 2 and solid pyrolysate out feed sections 6a, 6b allows control of the type of gas admitted into the atmosphere found in any sealable chamber of the pyrolysis plant. The vacuum system with its vacuum pump 54, associated piping 55,56, valves and sensors; used as a flushing means, lowers the critical levels of oxygen found in the vessels, thereby preventing the occurrence of

445 those conditions which support combustion, when necessary can be used to remove pyrolysis gases from chambers and allows a selection between air, flue gas or non-condensable fuel gas to be directed into any part of the process containers or vessels.

Flue gas for flushing is captured from the top of the thermal oxidiser at the duct 12 where it exits around 1,000 degrees. It is drawn into a piped take-off which runs through a large heat

450 exchanger to cool it to ambient temperature, after which it is drawn to the required vessel by vacuum control through a network of valves and pipes. Non-condensable fuel gas is recovered from the distillation process where it is released via the oil/water/gas separator 25 and plumbed into the main gas line 67 which feeds both the gasometer 73 and the burner head 50. This fuel gas is drawn off from the gas line 67 under vacuum 54 and directed to the required vessel again

455 through pipe and valve control.

These two types of gas (flue and fuel) plus the air entering the loading hopper 2 with the tyres are all drawn via the vacuum pump 54 into a discharge line 66, then directed to a ballast tank 72 where they mix at a slight pressure. This air/gas vacuum discharge becomes mixed in the ballast tank 72 as combustible fumes. From there it is plumbed 66 directly to the burner head 460 50, 120 where all the fumes, gases and air mix are burned with the incoming fuel gas and blown air, to generate the heat for the pyrolysis process.

This means there is no direct discharge from the process to atmosphere of any fumes or tainted air. All vacuum vapour discharges are captured and recovered. They are passed through the burner 50, 120 where all fumes and gases are combusted and finally discharged to atmosphere 465 up the flue and in compliance with relevant Air Discharge Consent regulations.

To facilitate the flushing and purging of the hopper 2, a vacuum pump 54 is provided to capture the gases purged from the hopper 2 via a release valve (not shown). The vacuum can be maintained at a constant draw by a pump 54 and gases are released from the hopper 2 by another release valve (not shown). The release valves may preferably be operated to open and 470 close automatically, or by a worker managing the operation of the overall pyrolysis system. The solid pyrolysate receiving chamber 6 may be similarly flushed and evacuated prior to use. All gases captured by the vacuum pump 54 may be fed to the burner 50, 120 for combustion or destruction as previously stated.

Between the hopper 2 and the pyrolysis tube 3 is a gate valve assembly, generally indicated by 475 arrow 27. The gate valve 27 is described in more detail later.

, The lower outside region of the hopper flange 2 and the upper outside region of the pyrolysis tube 3 are provided with cooling means in the form of water jackets 26. Both water jackets 26 serve to reduce the heat in the region of the gate valve 27 thus protecting important moving parts and accompanying seals 37 and gaskets (not shown) from excessive heat. It is desirable 480 to keep the seal area 37 of the gate valve 27 to below 250 deg C, and even more preferably to a maximum of around 200 deg C.

The water cooling jackets 26 around the seals 37 and in the solid pyrolysate extractors 107, 108, 109, 116, and 117 and around the solid pyrolysate receiving chambers 6, 136 (see later) have a water circulating system flowing through a cooling tower or radiators 75, to allow for 485 the recycling and temperature control of all the water being used in the cooling process.

The pyrolysis apparatus 3 is suspended by a beam structure (not shown) fitted underneath the gate valve 27 and secured to the process container members (not shown). Hence the gate valve 27 must be fabricated from a strong and resilient material. It is preferably made up of mild steel plate of between 16 mm to 20 mm thickness. Thermal expansion accommodators (not 490 shown) and seismic restraints (also not shown) are fitted to the pyrolysis apparatus.

There is either a plug door assembly 142 for the batch process or an extraction mechanism 107, 108, 109, 116, 117 for the continuous process between the bottom of the pyrolysis tube 3 -and the receiving chamber 6 or 136. Operation of the plug door 128 and extraction mechanism(s) 107, 108, 109, 116, 117 is described in more detail later.

495 The lower outside flange (not shown) of the pyrolysis tube 3 and the entire outside of the receiving chamber(s) 6 are provided with cooling means in the form of water jackets 26, 118, 119. The entire outside of the receiving chamber(s) 6 is covered with a water jacket in order to cool, as quickly as possible, the resultant solid pyrolysate material which falls through into the chamber(s) 6. Water is fed into the water jacket(s) 26, 118, 119 by the inlet valve (not shown).

500 HEAT-RESISTANT GAS-TIGHT SEALING MEANS

In Figures 2 and 3, the various aspects of the gate valve assembly are shown in isolation. The upper ends of the pyrolysis chambers are provided with airlock-type gate valves 27 for admitting feedstock into an oxygen deprived gas environment. This assembly incorporates a lower heat shield 32 which slides to block rising heat across the top of the pyrolysis tube 3, a 505 middle steel door 31 which when raised against a seal 3.7 renders a gas-tight fit, it also incorporates the upper holding door 112 to hold the feedstock before release, plus the sliding sleeve 113 which moves vertically to protect the seals 37 from abrasion from descending tyre pieces.

The gate valve 27 comprises a sliding body 31 made of 20 mm thick mild steel plate. The 510 sliding body 31 sits atop a lower, sliding heat shield 32, also made of mild steel plate around an insulated core. The bottom two door combination 31,32 is able to be opened and closed by the use of the actuating ram (not shown). One of several inlet pipes 134 is shown; they are provided for supply of non-condensable cooling/flushing gases around the seal. Water jackets 26 are shown in cutaway section surrounding the region of the gate valve 27.

515 Fig 2: It is important that feedstock be prevented from coming into contact with and damaging the seals 37 of the sliding door 31 of the gate valve 27, and also so that feedstock can not interfere with the opening and closing, then sealing of the sliding door 31. The lower portion of the hopper 2 is provided with means of a vertically moveable steel sleeve 113 to prevent the feedstock from coming into any significant contact with the gate valve 27 or seals/gaskets 37.

520 The gate valve 27 is also provided with pressure sealing means in the form of four air powered rams 38 located underneath the four corners of the sliding door 31, once closed.

In use, once feedstock is to be dropped into the pyrolysis tube 3, the four rams 38 allow for the lowering of the sliding door 31 from the bottom of the hopper 2. The sliding body 31 and lower heat protector 32 are then slid open to the position shown in the drawing Fig 3. The

525 vertically sliding sleeve 113 is then lowered by its ram (not shown) to actively protect the seal area 37. The holding door 112 in the hopper is then withdrawn by its ram (not shown) to open and release the tyre pieces. Feedstock is then able to fall into the pyrolysis tube 3 in order to undergo pyrolysis. The vertically sliding sleeve 113 is then raised back up into its rest position. The sliding door 31 and heat shield 32 are then slid back into the closed position, 530 where after the four rams 38 serve to push up and secure the sliding door up against the seal 37 on the flange at 26 on the bottom of the hopper 2, which is sealed against high temperature Viton or silicon seals 37 and the holding door 112 is then slid back to the closed position.

SEMI-CONTINUOUS TYRE SHRED INFEED

535 The existing plant arrangement can be adapted to function as a semi-continuous throughput process using tyre shred feed stock smaller than 100 mm diameter.

Figs 2 & 3: Tyre shreds 100 mm or smaller are fed into the top infeed hopper 2 as per the normal procedure. Once the hopper lid 101 is closed and the hopper 2 is purged by vacuum cycling 54, 55 as previously specified, the contents are dropped via opening the gate valve

540 assembly 27 into the pyrolysis tube 3 below. While loading into an empty pyrolysis tube 3, this cycle may be performed many times with the gate valve doors closed 27 each time for the reload, during oxygen removal by vacuum cycling 54, 55, until the pyrolysis tube is full. The final drop of tyre shreds will then rest on top of the existing charge but the gate valve 27 remains open. This means that tyre shred will rest both inside the pyrolysis tube 3, across the

545 open gate valve area 27 and up into the top loading hopper 2. The sliding sleeve 113 which protects the seals 37 at the gate valve 27 from abrasion from dropping tyres is lowered and remains in place during the time the shred is sliding downwards.

Alternatively the tyre shred can always be maintained at a level below the closed gate valve assembly 27 and reloaded when there is sufficient headspace created from the slumping and/or

550 downward passage of material, to receive more tyre shreds. While the mass of the charge is pyrolysed and eventually slides down the tube 3 to be discharged at the bottom end via the extraction mechanism (see later Figs 4 and 5) located there, the upper level of the tyre shreds will subside down through the infeed hopper 2, past the seal protecting sleeve 113 and the open gate valve 27, to eventually reside inside the pyrolysis tube 3. At this point the sliding sleeve

555 113 is raised, the gate valve assembly 27 is closed, the middle door 31 is lifted up against its seals and the holding door 112 is closed. The tyre infeed hopper 2 is then reloaded, vacuum purged 54, 55 and the loading cycle of the pyrolysis tube 3 for semi-continuous infeed is repeated.

A remote sensing device (not shown) capable of responding to the presence of infeed material 560 is fitted to the topmost door 101 of the tyre loading hopper 2 and is configured to read to the level of the top of the tyre charge, as it subsides slowly down past the open gate valve assembly 27 and into the pyrolysis tube 3. In this way the remote sensing device provides an accurate indication of the headspace distance once the tyres have subsided to a measured level below the gate valve 27. The gate valve assembly 27 can then be closed with no risk of 565 jamming against protruding tyre pieces. The tyre shred loading process into the hopper 2 can commence and the cycle be repeated. The remote sensing device may be automatic; it may be optical or involve physical contact means, and it may involve image analysis or a person who views a screen and controls actuators in order to control the tyre loading hopper.

To support this method of semi-continuous infeed of tyre shred the following adaptation to the 570 process has been instigated;

Figs 10 and 11; Non-condensable fuel gas recovered from the distillation column 16 is pumped into the pyrolysis tube 3 from three locations ; (a) through the bottom discharge gate valve and assembly via pipe 134 so that it flows upwards past the extraction apparatus 107, 108, 109, 116, 117 and into the pyrolysis tube 3 to prevent the downward flow of pyrolysate gas and

575 liquid onto the lower assembly. It then flows up through the charge and out the manifold 68; (b) through the topmost gate valve assembly 27 via the pipe 134, through two entry points 134 and around the seals 37 behind the sliding sleeve 113, to descend over the tyre shreds and to flow out the manifold 68; and (c) through the top section of the tyre infeed hopper 2 to flow downwards and to buffer against the uprising pyrolysate, then to flow out the manifold 68. This

580 downward flow is to prevent the 'chimney effect' which would otherwise cause hot oily pyrolysis gas to flow upwards, past the gate valve 27 and into the tyre infeed hopper 2. This downward fuel gas flow prevents any build up of undesirable pyrolysate residues in the upper tyre infeed hopper 2.

In each of the three gas flush flows, the incoming flushing gas mixes with the evolving and 585 outgoing pyrolysate gases, to become part of the total flow exiting through the manifold 68 and flowing across to the distillation column 16.

CONFIGURATION OF PYROLYSIS / HEATING CHAMBER

Fig 1 : The heating chamber 4 preferably operates at a working temperature of between 300° to 700° Celsius; more particularly about 500° to 600° C is suitable. Temperature gradients within 590 the heating chamber 4 are preferably minimised especially if cooling gas is admitted; if necessary by the use of stirring fans 14a, 14b. Optionally the outside of the pyrolysis tube 3, inside the heating chamber is fitted with one or more heat transfer fins (not shown) which are intended to intensify the heat within the pyrolysis tube by more effectively transferring heat from the heating chamber. 595 Alternatively or additionally, an inlet air valve 13 passing into the heating chamber is used to introduce cooler air or anoxic gas (possibly under pressure) as or when required. A temperature probe or probes (not shown) may be positioned in the walls of the heating chamber and used to monitor the temperature as part of process control. A thermostat or virtual thermostat may automatically allow cool gas inflow ducted from a blower (not shown) when the temperature

600 goes above a pre-determined point. This could also be done manually.

The main section of the pyrolysis tube 3 stands vertically inside the heating chamber 4 where its surface is exposed to the full impact of the heat entering the chamber from the thermal oxidiser 10. Each end of the pyrolysis tube 3 has a fitted flange (not shown) which rests outside the heating chamber 4. The pyrolysis tube 3 is connected by its fitted flanges which hold the 605 water cooled jackets and are bolted to the upper infeed hopper 2 and to the lower receiving chamber 6 or plug door assembly 142.

The pyrolysis tube 3, top feed hopper 2 and lower solid pyrolysate receiving chamber 6 or plug door assembly 142 may preferably be supported by a mechanism (not shown) to protect the heated metal sections from stretching and elongation due to metal expansion. This may be

610 provided by a spring mechanism to allow for the thermal growth or shrinkage in the metal tubes or chambers. The pyrolysis system may preferably be designed as a unitary structure where all the parts are supported or suspended from the gate valve housing 27, thereby allowing for normal and unimpeded thermal expansion and movement. The spring mechanism may also function as a type of damper or sympathetic support to the whole unit. There may

615 also be a sideways damper (not shown) to protect the pyrolysis system from excessive movement in the event of a seismic shock. The support mechanism may also be connected to a load cell (not shown) via sensors which will provide data on the weight and stress factors in the system.

Each pyrolysis 3 tube is formed with a gentle flare outwards for the bottom three meters, to 620 allow for ready movement of product down the tubes and minimise the risk of bridging.

CONFIGURATION OF HEATING CHAMBER

As previously described, the inside walls of the heating chamber 4 have an insulative and/or protective material to minimise loss of heat and/or to protect the chamber4 from deterioration or corrosion due to the hot and mildly corrosive environment. For example, the 625 insulative/protective material may include a mixture of "Kaowool" backed with vermiculite and/or a rigidiser to protect the "Kaowool" outer surface from erosion or corrosion from the passage of hot and/or corrosive gases. Furthermore, there may be provided an exhaust flue 15 extending from the heating chamber 4 and outside the process container to the atmosphere, preferably at a height above the loading

630 hopper 2. This exhaust flue 15 may be provided with means to clean the resultant exhaust gases, such as an air scrubber (not shown). This exhaust flue 15 may be fitted with a damper system 104 to allow for graduated opening or closing of the top of the flue 15, thereby controlling the rate of discharge of flue gas. This damper 104 allows for control of the backpressure and heat retained inside the heating chamber 4 which assists in supporting the cold

635 start up of the system, the maintenance of steady temperatures in the heating oven 4 and the through flow of combustion gases in the event of it being operated as a flare, where larger quantities of gas are combusted and rapidly discharged to atmosphere. The damper can be operated by automatic control using appropriate sensors and an actuator (not shown).

EXIT FROM HEATING CHAMBER

640 There are two methods for removing the solid pyrolysate from the pyrolysis tube.

Fig 13 and 14: One method used for batch processing utilises a plug door assembly 142 which releases the total contents of the pyrolysis tube into a removable receiving chamber 136.

Fig 5 and 6 and 7: The other method for continuous processing has an option from any one of four types of extraction mechanisms 107, 108, 109, 116, 117 described below, which 645 continually removes the solid pyrolysate from the steadily descending mass, to discharge the product into a fixed double chambered receiving system 6. In turn the lowest chamber 6b, 6c feeds the solid pyrolysate onto a conveyor 106 for moving the char/wire mix across to a materials handling section (not shown).

THE PLUG DOOR OPTION - FOR BATCH RELEASE

650 Fig 13 and 14: The specific adaptation for release of pyrolysed first shred material with associated long pieces of wire is called the plug door assembly 142. The plug door is designed to operate with the batch process. This unit is an assembly designed to hold the pyrolysing charge up inside the pyrolysis chamber 3 at a level above the oven floor thereby ensuring complete pyrolysis and overcoming the -cold end" effect known to those skilled in the art.

655 Support of the tyre shred at the bottom end of the pyrolysis tube is achieved by means of a retractable plug 128 fitted to both seal the bottom end of the pyrolysis tube 3 and to hold the contents of the pyrolysis tube in place for the duration of the cook cycle.

The plug 128 is of sandwich construction (not shown), its topmost layer is steel over a thick copper plate functioning as a heat sink, beneath which is a layer of ceramic insulation. The

660 whole plug structure 128 is encased as a cylinder of mild steel resting on a retractable vertical support arm 130 as previously described. The whole assembly is supported by and moves transversely along two parallel cast iron tracks (not shown) inside a heavy steel gas-tight case 142. During the pyrolysing process a gas flush system 134 is fitted to feed non-condensable gas through the plug casing 142 and around the edges of the plug 128 when it is seated in the 665 upper recess 131. The gas flows around the metal to metal contact area 132 at the periphery of the plug 128 and then pass up through the pyrolysing mass thereby assisting the transport of volatised tyre material, up through the manifold 68, across to the distillation tower 16.

The plug mechanism 128 is integral with a heavy assembly case 129 inside which it moves. Functionally it is an adaptation of the gate valve 27 and is operated by a pneumatic cylinder 670 130, similar to the top loading gate valve 27. The main difference is that the sealing plug 128, instead of the steel door 31, slides from its horizontal recess 129, across the diameter of the bottom extent of the pyrolysis tube 3.

Once it has been moved across by the ram (not shown) into a position below the pyrolysis tube 3, another ram 130 raises the oversized plug 128 vertically into the upper recess 131 set at the 675 base of the pyrolysis tube 3 and which is slightly wider than the rest of the tube above. The plug 128 is raised to seat against the bottom face 132 of the upper recess with a metal to metal contact between the top of the plug 128 and the recess 131. In this way the incoming tyre load is caught and supported as it falls from above and is positioned into the hot pyrolysing zone by the support of the plug 128 until the cook cycle is completed.

680

Before the plug 128 is operated to drop the solid pyrolysates, the plug assembly bottom sliding door 151 already in position, picks up the receiving bin lid 138 and withdraws it into the body of the case 129, then the plug assembly sleeve 152 lowers to cover the seals 139. At this stage the receiving bin 136 is open to receive the falling solids once the plug 128 descends and 685 retracts.

At the conclusion of the batch cook cycle the plug support ram 130 lowers and the entire column of supported pyrolysed tyres follows it downwards. When the plug 128 reaches its lowered position it is then horizontally retracted by a ram (not shown) pulling it along its cast iron tracks and back into its lower recess 129. With this horizontal movement, as the plug 128 690 is drawn back it passes under the edge of a horizontally aligned scraper 133 which dislodges any surplus pyrolysis material off the top of the plug 128. The pyrolysed mass, now unsupported by the plug 128, slides downward under the effect of gravity and into the receptacle below, 136.

CONTINUOUS PRODUCTION EXTRACTION OPTIONS 695 When the tyre plant feedstock available is second shred i.e. uniform sized pieces smaller than 100mm, the plant is operated as a continuous process. The uncooked tyre pieces descend through the pyrolysis tube 3 and continually evolve pyrolysate gas under the impact of the heat. As they descend further under the weight of incoming material above the tyre pieces lose their volatile contents and are completely cooked. At this stage the solids are drawn by the

700 action of the extractor mechanism which is controlled to remove the cooked material. See Figs 6 and 7 for the descriptions of four variations for the solid pyrolysate extraction mechanism are provided; the single extraction roller 107, the dual roller 108, the staggered prongs system 116, 117 and the rotary vane extractor 109. The variation chosen may be matched to the specific characteristics of the feedstock being used and the type of flow rates characteristic of that

705 feedstock e.g. char/wire, bio-solids, plastics or combinations thereof.

The pyrolysate char/wire will bridge at the slightest obstruction which then causes the material to lodge in the pyrolysis tube until some mechanical force upsets the bridging effect. This feature is utilised for the continuous outfeed of hot material from the pyrolysis tube, which is accomplished by positioning an extractor mechanism horizontally across the bottom of the 710 tube. The descending pyrolysed material then bridges as it comes into contact with the extractor. Once the extractor is activated, its physical action catches and removes the char and wire by physically drawing the material across, down and out of the bridged mass above. The remaining material then descends partly under the weight of the mass above and partly being drawn down by the extractor's action.

715 Several extraction methods have been judged suitable for working with the char/wire mix they are the claw roller, the dual rollers, staggered prongs and the rotary vane.

The combined effect of the bridging and extractor unit action allows for removal of hot pyrolysed material at a controllable rate, which allows the plant to function as a continuous operation, thereby increasing the total output and plant efficiency.

720 SINGLE CLAWED ROLLER-EXTRACTOR OPTION

Fig 4: We call this the "bear claw roller". One option for the semi-continuous extraction of the hot pyrolysed char/wire mix from below the pyrolysis tube 3 and just beneath the level of the pyrolysis oven floor is the single extraction roller 107. This consists of a steel cylinder mounted on bearings transversely and positioned centrally to the pyrolysis tube 3, to take 725 advantage of the bridging properties of the char/wire mix as it sits at the bottom of the pyrolysis tube 3. Once the roller 107 releases the hot material the char/wire drops vertically down into the drop out chamber 105. This roller 107 is driven externally and from outside the steel casing by a mechanism 146 of gear and chain or pneumatic ram and lever. There is provision for water cooling by plumbing 730 water lines (not shown) in and out of the roller via a flexible coupling to the end of the roller and out of the line of fall of the hot pyrolysis products. Extraction of the char/wire mix resting above the roller 107 is accomplished by rotating this horizontal cylinder 107 either via oscillation across an arc within 180 degrees or by rotating it completely through 360 degrees.

The size of the roller 107 and its proportion to the pyrolysis exit and its mounting configuration 735 are known to those conversant with the art. This arrangement could consist of a square exit box (not shown) holding the roller unit 107 which is fitted by formed metal to the base of the pyrolysis tube 3.

To aid extraction of the pyrolysed char/wire material, a series of metal claws 110 are fitted to the outside surface of the roller 107. These are set at a pitch and interval across the roller 740 surface in a suitable pattern determined by those conversant with the art. The claws 110 are designed to bite in one direction and to release trapped material such as wire shreds when rotated in the other direction. The released material drops into the drop out chamber 105.

The hot char/wire will receive partial cooling through contact with the water-cooled roller 107 as it is being discharged downwards into the next section of the plant.

745 THE DUAL ROLLER OPTION

Fig 4: The configuration of this variant of the semi-continuous extraction system has two water cooled metal "bear claw" cylinders 108 transversely mounted below the oven floor and resting on bearings at a fixed distance apart. This distance is determined by the size of the tyre shred and the diameter of the roller-extractors vs. the diameter of the pyrolysis tube 3. They are 750 configured to roll towards each other but with the provision to back up by counter rotational movement. To control the rate of extraction of the hot material they can operate in concert or individually. The rest of the description of their function and operation is the same as above for the single roller.

THE SYNCHRONISED PRONGS EXTRACTOR OPTION

755 Fig 5 and 6: This system consists of an upper 116 and lower 117 set of prongs ram actuated (not shown), in a configuration at right angles to the pyrolysis tube 3 and below the oven floor. A double set of prongs 116, 117 is arranged to work in concert to accomplish the stepwise controlled release of the hot char/wire mix. The top set of prongs 116 holds the solid pyrolysate load due to a combination of the bridging effect and their physical restraint of the material,

760 while the bottom set 117 are withdrawn from across the pyrolysis tube 3 to create an opening, thereby allowing for the release of the intervening load. The bottom prongs 117 are made with closer gaps between the tines to limit any downward flow of smaller particles

The lower set of prongs 117 are reintroduced across the width of the lower part of the opening 3. Once the lower prongs 117 are in position, the upper set of prongs 116 are withdrawn slowly

765 to cause a more controlled downflow of material from the mass above, which allows a fresh load of the char/wire charge to settle into the cavity between the two sets of prongs. These upper prongs 116 are then reintroduced into the chamber to secure the material above in preparation for the next prong movement and unloading cycle. This synchronised process of prong movement allows for an accurate and controlled cook time of the tyres by the control of

770 their flow rate out of the pyrolysing zone and into the drop out chamber 105 .

The prongs 116, 117 are withdrawn outside their chamber below the pyrolysis tube and into a gas-proof containment vessel 147 which is sealed from the atmosphere by a formed metal jacket. At their farthest extension, the prongs 116, 117 reach across the width of the pyrolysis tube 3 to rest on a recess 114 in the opposite wall of the vessel. When withdrawn the prongs 775 116, 117 go back through a sleeve 148 designed to scrape off any adhering material. The protruding end of each prong has a bull-nose shape 115 to allow for its passage through the char/wire and to minimise any adhering of the mix. There is preferably also provision for cooling the prongs (not shown), capable of keeping these regions below 100-200 deg C.

THE ROTARY VANE EXTRACTOR OPTION

780 Fig 4 (lower portion): This unit consists of a steel vane 109 transversely mounted on bearings and positioned centrally across the pyrolysis tube and below the floor of the oven. The vane 109 is driven externally from outside the steel casing by a gear and chain mechanism 146. It has between four and eight equal chambers in the form of vaned segments 109 which are rotated vertically to scoop portion of the char/wire mix from the pyrolysed mass resting in the

785 tube 3. The leading edge of each vaned segment 109 may be fair faced or may have a series of teeth welded to its outermost edge, which function to scavenge material into the vane chamber 109.

The vane 109 can rotate continuously in one direction at an extraction rate to match the pyrolysis system throughput. The vane 109 may also be operated cyclically through 360 790 degrees by counter rotation. As the vane 109 turns the captured char/wire is released to drop down into the drop out chamber 105. The central axis of the vane may be hollow to allow for the circulation of cooling water (not shown).

RECEIVING CHAMBER FOR BATCH PROCESS Fig 14: The arrangement below the plug system 142 is designed to handle the sudden vertical 795 descent of the entire solid contents of the pyrolysis tube 3 as the supporting plug 128 is withdrawn. The batch process solid pyrolysate receiving chamber 136 is fitted against the bottom of the plug gate valve casing 129 with a flexible seal 139 around the circumference of their temporary union. The lid 138 is already fixed in place across the sealing rim 140.

The receiving procedure includes provision for a vacuum oxygen purge process since the solid 800 pyrolysate is mainly red-hot carbon (mixed with wire) and would combust in air while hot; releasing gas, heat, and destroying a possibly marketable commodity. Therefore, after the removable receiving chamber 136 is returned to join the gate valve casing 129 with its lid 138 in place, a vacuum purge procedure via port and pipe 56 evacuates the air, the chamber is purged with flue gas, evacuated again and then fuel gas is bled in. The plug assembly bottom 805 sliding door 151, already in place over the receiving bin lid 138 then with a magnetic actuator (not shown) picks up the receiving bin lid 138 and withdraws it transversely into the body of the case 129. The plug assembly sleeve 152 lowers to cover the seals 139, 140. The receiving bin is now ready for the descent of the solid pyrolysate. The butterfly valve (not shown) in the gas expansion line 135 is then opened and the bottom pyrolysis plug door 128 drops open to 810 release the hot pyrolysed char/wire which falls into the receiving chamber 136. The vacuuming and gas flushing of the removable receiving chamber 136 is accomplished by a quick connect vacuum coupling port 56 which is fitted to the upper section of the receiving chamber and connects the vacuum pipe line 56.

The gas expansion line 135 (of large diameter) is fitted through the back of the casing of the 815 plug gate valve 129 and the mild steel gas expansion pipe line 135 then runs outside the process container along with the other pipework to reach the gasometer 73. This prevents a possible surge of gas under pressure passing up through the pyrolysis tube 3 which could unnecessarily stress or burst the safety burst discs (see Fig 12) which are installed above the tube 3 and which are designed to protect the total system from pressure spikes and to cope with 820 uncontrolled expansion events. The pipe line 135 with its large diameter readily conveys the expanded gas surge across to the larger volume storage capacity of the gasometer 73 where it is received and held for later use. A butterfly valve (not shown) fitted in this high volume expansion line 135 is closed for the purpose of isolating the receiving chamber 136 during the vacuum cycle and then once the chamber is purged and before the solid pyrolysate is dropped, 825 it is opened ready to allow the rush of expanding gases to flow across to the gasometer 73. The line after the valve (not shown) incorporates a mesh filter to capture any fine particulates which are carried over by the gas expansion, and a sump at the first bend where any condensable liquid is collected from the now cooled gas. Once heated the tyre shreds exhibit a slumping effect whereby they slide down due to the

830 effects of temperature (500 N 600 degrees C) which causes them to soften and pack together in the pyrolysis zone. The result is more headroom for loading more tyres. To take advantage of this effect the plant is operated by a semi-continuous loading process which utilises the design of the gate valve assembly to be opened and closed in a sequenced manner. This permits the maximum flow of tyres into the pyrolysis tube where they continuously descend as a

835 consequence of both the slumping and of the actions of the extractor mechanism below.

The downward movement can be monitored with a sensing unit to ensure no risk of product blocking the gate valve in its closing sequence between tyre loads. Benefits of this method include long uninterrupted cycles where the plant is operating at a steady state, less wear and tear on the plant through minimising the gate valve actions and improved energy efficiency 840 through the continuous feed rate reducing the temperature cycling of the equipment.

Once the char/wire is received in the removable bottom section 136, the butterfly valve is closed and the bottom pyrolysis tube plug door 128 is resealed against the pyrolysis tube 3. The removable bin 136 sown in Fig 14 is then capped with a steel lid 138 having seals 140 to prevent exposure to the open air, then lowered from its connection with the gate valve casing 845 129. The receiving chamber 136 is conveyed out of the process area and across to the cooling tumbler (not shown).

The cooling tumbler consists of a specialised steel cradle (not shown) to receive and hold the removable receiving chamber or bin 136, which can be tipped via a lifting mechanism or fork truck onto the horizontal axis to optimise the tumbling and cooling process. It has a motorised 850 drive to rotate the bin in the frame and thereby allow the hot contents to radiate their heat out through the walls of the bin 136. The motorised drive is powered through to a boss 141 on the base of the bin 136 via a geared chain and sprocket mechanism.

The bin 136 can be cooled either through a water cooled jacket 137 or by spraying water on its outside surface to facilitate loss of heat from the tumbling char/wire mass inside. Because there

855 will be a contraction of the gas contents due to cooling, a relief valve (not shown) should be fitted preferably at the top end of the bin and through its steel jacket to guard against such negative pressure effects. Once the cooling process is complete the bin 136 can be released from the tumbling frame and its cooled contents are transferred into the materials handling section of the plant. Several of these bins 136 can be used to receive, cool and discharge the

860 pyrolysed product and are recycled to match the plant's production rate.

A fork lift (not shown) with a proprietary attachment is one method for moving the bins. Another method is the use of a trolley system (not shown) on rails set into a concrete pad on the ground. This arrangement allows the bins 136 to be moved to and from the pyrolysis process area and the cooling and product transfer areas, using tracks which are fixed in an 865 arrangement according to the geometry of movements required. This setup allows for accurate placement, installation and removal of the bins 136 through their cycle of operation. The bins 136 may have jacks fitted to their feet to ensure accurate alignment of their seal 139 against the outer rim of the gate valve casing 129 when they are positioned to receive the pyrolysate discharge.

870 RECEIVING CHAMBER FOR CONTINUOUS PROCESS.

Fig 7: The preferred embodiment of the pyrolysis tube 3 includes an outward flaring of the tube to allow for free downward movement of material, to prevent binding. In a continuous process the solid pyrolysate is released through the particular extractor 107, 108, 109, 116, 117 and received in a fixed double chambered arrangement 6. The solid pyrolysate extraction 875 process using roller(s) 107, 108 or prongs 16,117 or rotary vane 109 is operated at an operating discharge rate preferably set so to match the rate of completion of the pyrolysis process of the shredded tyres, which in turn may be influenced by the customer's specifications for the pyrolysed carbon char.

Accordingly the discharge rate of the solid char/wire is calculated by the time taken to cook off 880 the volatile products from the tyre shreds as the solid portion moves downwards inside the pyrolysis tube 3 and the volatile portion evolves as pyrolysate gases to exit upwards through the manifold 68. This cook rate is determined both by the residence time of the pyrolysing materials inside the hot zone 3 and the operating temperatures achieved there.

From the bottom end of the pyrolysis tube 3 the solids discharge rate is managed in three ways;

885 (a) by controlling the infeed of fresh tyre shred at the top end 2, which can be established by readings from the remote sensing apparatus mounted on the lid of the infeed hopper, (b) by controlling the arc of movement of the roller(s) 107, 108 or prongs 116, 117, or rotary vane 109 or (c) by controlling the timing and number of movements of the claw roller(s) 107, 108 or prongs 116, 117 or the rotation of the rotary vane extractor 109. The ultimate control of the

890 discharge rate of the char/wire mix is accomplished by regulating its drop out rate through a sequence of two fixed receiving chambers 6a, 6b. Each receiving chamber 6a, 6b is of a known volume which can receive a specific quantity of pyrolysed material in a specified period of time e.g. 50 litres in 5 minutes.

The lower chamber 6b has a gas tight seal (not shown) provided by downward movement of

895 the lower door of chamber 6a and the upward movement of the lower door of chamber 6b, each to press against a sealing ring thereby providing the gas tight seals to enable the vacuum 54, 55 to be drawn. Control of the gas environment in chamber 6b is integral to the pyrolysate discharge process onto the conveyor 106. The discharge rate of the material through each of these two chambers 6a,b can be controlled by the process operator and can also be 900 automatically programmed into computer sequenced controls.

The entry into and discharge from the first receiving chamber 6a of the known volume of pyrolysed material can be achieved by steel prongs 111 which are moved horizontally across the upper drop out section 105 of the first receiving chamber 6a, by either releasing the char/wire mix pyrolysate down into the first receiving chamber 6a or by retaining it in the drop 905 out section 105. Action of the prongs 111 takes advantage of the bridging properties of the char/wire mix and holds any excess material until after the known volume has been released through the upper gate valve 27. The number of tines used for these prongs 111 is dependent on the cross-section area to be covered across the chamber 105 and the bridging characteristics of the char/wire mix.

910 The function of the first receiving chamber 6a is to provide control of the volume discharge rate into the second receiving chamber 6b, so that there can never be an overload of material to compromise the operation of the upper gate valve 27 and its seals (not shown) as they release the char/wire into the second chamber 6b below. The first receiving chamber 6a is of a lesser volume that the second receiving chamber 6b and has a water jacket 118 to draw heat from the

915 load and assist the cooling process.

Once the extractor mechanism, 107, 108, 109, 116, 117 is operating to pull out the solid pyrolysate there is a flow of material which can be controlled. The horizontal prongs 111 are then moved across the drop out section 105 to both prevent any excess solids from continuing to fall downwards and to ensure that when the upper gate valve 27 does open only a controlled

920 amount of pyrolysed material falls into the second receiving chamber 6b. This ensures that excess material does not fall downwards to otherwise choke the operation of the upper gate valve 27. Once in the second receiving chamber 6b the char/wire is held and cooled by a water jacket 119 and for a period determined by the plant's throughput flow rate. Before the solids are released onto the conveyor 106, the bottommost chamber 6b is vacuumed to remove any

925 fuel gas, extra volatiles are captured at this point and conveyed to the burner 120. Flue gas is then introduced into the second chamber 6b and the material is dropped through the lower gate valve 27 onto the conveyor 106.

When the second chamber 6b is empty it is closed and evacuated again, non-condensable gas is introduced and it is ready to receive another load. The result is a controlled discharge into the

930 conveyor system 106 with no likelihood of overload and hence jamming of the gate valve mechanisms 27. Hence the conveyor system 106 is known to be receiving a measured and known load of pyrolysed material, so it can be operated with confidence that the risk of overload and blockage at the loading point has been eliminated.

As an option the entire outside of the solid pyrolysate storage chamber is fitted with cooling

935 means such as a water jacket 118,119. Alternatively, the solid pyrolysates in the receiving chamber may first be cooled by any suitable means not shown) prior to being removed from the chamber. For example, the char/wire mix could be sprayed with a cooling liquid such as

LPG or cooled non-condensable gases. In such an embodiment the LPG would be vaporised and may preferably be recovered and recondensed by the distillation apparatus or a separate

940 radiator apparatus, or burnt.

Preferably, the solid pyrolysis receiving chamber 6 b is also flushed of oxygen by vacuum process as previously described. The solid pyrolysate material i.e. char/wire mix is dropped from the bottom receiving chamber 6 b, through the lower gate valve 27 onto the conveyor 945 106.

THE CONVEYOR

Fig 1 & 7: The cowled conveyor 106 moves the char/wire across to the materials handling section and the mix is cooled while being conveyed by radiating its heat and by a counterflow of cool flue gas. Instead of a conveyor 106 an enclosed augur system (not shown) could be

950 incorporated with the same provisions for cooling and gas control. Either of the above mentioned material transport means is preferably separated from the atmosphere by a gas-tight metal cowling 150 and has two functions; (a) to move the pyrolysed materials out of the pyrolysis zone and across to the materials handling section, and (b) to provide for radiant cooling of the char/wire mix as it is moved across the conveyor distance 106 in an oxygen

955 starved environment.

A piped flow of flue gas 121 runs inside the cowling 150 opposite to the conveyor movement and acts to cool the material and to direct any dust and any residual volatile material still out- gassing from the char, back to the burner head 120 via a ducting system (not shown) including a filter and flashback ancestor. The flue gas is cycled through a pump and heat exchanger 122 to 960 further assist the cooling process. With each incoming load of pyrolysed char/wire the enclosed conveyor 106 receives extra flue gas. Any surplus gas is captured and bled off to the burner 120. One form of conveyor 106 consists of a steel belt mounted on rollers. Its steel construction and gas tight metal cowling 150 allow for the continual radiation of heat from the char/wire as it is 965 conveyed to the hopper (not shown) for the carbon handling system.

Optionally, the solid pyrolysate receiving chambers 6a,b and conveyor 106/and/or augur systems are substantially elongated, thus enhancing the potential cooling area for a given surface, which may be increased in capacity to suit production requirements.

The solid char may be ground into powder and all steel contaminants removed by magnetic or 970 other recovery means before a carbon fraction is sold as such.

SAFETY/EXPLOSION CONTROL

Fig 12: The apparatus, in particular the pyrolysis tube 3 is fitted with a safety release mechanism having dual burst disc 125, 126 which allows for the immediate release of pressure within the tube or chamber in the event of an overpressure event or emergency shut down.

975 The tyre infeed end, gate valve casing 27c, may be fitted with an explosion disc 125, 126 adapted to burst and release all pressure and gas into the atmosphere when a certain pressure has been reached in the connected pyrolysis tube 3. These discs 125, 126 are used as pairs and valve means (here shown as two separate butterfly valves 123,124) are used to expose or isolate either disk from the interior of the gate valve casing 27c. Preferably, the safety release

980 mechanism may be positioned to release the gas pressure at least 5 metres above ground level. Once the initial pressure has been released through the burst disc e.g. 125, the further discharge of pyrolysate gas to atmosphere can be minimised by closing the open butterfly valve e.g. 123. This valve e.g. 123 functions as a gas capture unit by sealing the pipe 127 upstream of the burst disc 125, thereby redirecting the pyrolysate gas back through the plumbing 68 to the distillation

985 column 16 and preventing any continuous release of pollutants to air. A dual 102 Fig 12 controlled by separate valves 123,124 will allow for resumption of plant operation after an overpressure event, because the second burst disc e.g. 126 can then be connected via its now opened butterfly valve 124 to protect the plant while the first 125, isolated by its butterfly valve 123 is replaced or otherwise reset.

990 THE THERMAL OXIDISER (Burner)

Fig 1: As previously stated the Thermal Oxidiser 10 is the destination for all the air/gas mixes recovered by the vacuum system. It has at least five functions; (a) the efficient control of the process temperature/heating requirements through its combustion system; (b) the destruction of the fume-loaded gas/air mix generated by the vacuum processes; (c) the thermal destruction of 995 sulphur compounds (such as mercaptans) found in the fuel gas; (d) the ability to operate as a flare, whenever excess generation of fuel gas from the pyrolysis process needs to be rapidly burned, (for example, to release combustible products directly to atmosphere in the event of an emergency shutdown of the plant when surplus quantities of fuel gas may require to be rapidly destroyed ) and (e) the safe disposal through thermal decomposition of any contaminated 1000 liquids generated action on site. Heat generation is of course a valuable function.

Fig 1: shows a preferred thermal oxidiser generally indicated by arrow 10. Oxidation is inherently exothermic and the thermal oxidiser 10 serves both as a combustion chamber and flare for excess burnable gas. The thermal oxidiser 10 has considerable flexibility in its operation which allows for management of both the process temperature requirements and the 1005 need to handle considerable fluctuations in fuel gas volumes.

The thermal oxidiser 10 has at least the capacity to support four pyrolysis heating chambers arranged in a modular array. The thermal oxidiser 10 is supported on a concrete base 46 atop ceramic legs 48 and includes a firebox 47 made from high temperature castable cement. The stoichiometrically variable burner 50 is provided with a passive thermosiphon 144 with a water 1010 reservoir to protect the burner 50 from the impact of excess radiant heat after shutdown.

The rest of the thermal oxidiser consists of ceramic fibre configured around a hollow vertical heat zone or residence chamber 11 capped off with a ceramic fibre ceiling. The hot air is ducted 12 at the top of the vertical heat column transversely through to the heating chamber 4, by means of a duct 12 formed from ceramic fibre. Each Thermal Oxidiser can be configured 1015 with ducts so manifolded as to supply heat to up to four heating chambers. The ceramic fibre is surface coated to resist the thermal stress of the burner flame and is backed with "Perlite" insulation, supported by sheet steel walls fastened to a steel frame (not shown). Preferably the inside of the residence chamber 11 and/or the duct 12 leading from it includes a coating, for example ITC 296A, as previously described to protect it from the heat and/or degradation.

1020 The thermal oxidiser 10 is also provided with a resealable aperture 49 to which a diesel burner 64 may be fitted for the initial start up. In use, a diesel burner 64 is fitted to the residence chamber 11 via the aperture 49. The diesel burner 64 raises temperatures to approximately 700 deg C, the regulated minimum operating temperature for the thermal oxidiser 10, after which it is removed and the aperture 49 is sealed or plugged with a plug made from a suitable high

1025 temperature resistant material. Then the main burner 50 raises the temperature to approximately 1100 deg C.

One version of the burner 50, which is shown in greater detail in Fig 8, consists of a planar array of scores of thin capillary tubes, generally indicated by arrow 51, mounted through high temperature ceramic material at arrow 52. Each capillary tube 51 acts as a Bunsen-like burner 1030 with its companions to provide a concentrated flame front. Their relatively narrow tube diameters should prevent flash-back of the air/fuel mix back through the ceramic sheet. There is a flash-back arrestor (not shown) fitted to the gas line before the burner.

The burner fuel gas feed 67 may be optimised regardless of actual fuel gas composition by an oxygen analyser (not shown) in the residence chamber 11, to sense oxygen levels, and 1035 providing feedback to a fan 103 forcing air through a duct 103 a to the burner 50 to support the combustion air/fuel ratio. The gap 53 between the ends of the capillary tubes and the residence chamber 11 is approximately 100 mm.

Fig 10 & 11: The gas supply for the burner 50 is primarily from a gas line 67 connected between the gasometer 73 and distillation tower 16, with a secondary gas feed 66 from the 1040 vacuum ballast fume tank 72 (used to purge the hopper 2 and/or solid pyrolysate receiving chamber 6, 136).The gas flow from waste tyres commonly has up to 30% by volume of hydrogen, the rest being hydrocarbons and therefore has a widely variable oxygen requirement for its combustion.

The preferred burner 120, specialised for the non-condensable gas supply 67, consists of three 1045 large customised burner heads, each with its water cooling bath 144 and protected by a flashback arrestor (not shown) at the gas inlet connection 67.

Fig 1 : The air supply for this burner 120 is provided primarily from a fan blower 103, the air output of which is managed by a variable speed controller on its motor (not shown). The resultant flow of air is directed by a flexible hose 103 a through to feed an air inlet manifold

1050 alongside the burner heads. The air output of the blowerl03 is also regulated by sensors inside the thermal oxidiser 10 and the heating oven 4, which provide data on the process oxygen and temperature levels, thereby allow for increase or decrease of the air flow rate and volume according to process requirements. In the event that cooling is required in the heating chamber 4 because the pyrolysis temperatures are above target levels, additional air can be blown

1055 through the blower 103 and thence through the thermal oxidiser 10 and into the heating chamber 4. This amplified volume of air flow when done in conjunction with a shutting down of the burner's fuel gas feed 67 and an opening of the exhaust flue's damper 104, serves to lower the temperature in the thermal oxidiser 10 and the heating chamber 4.

Conversely the increase of fuel gas feed 67 and air feed 103 a to the burner 120 coupled with 1060 flue damper control 104 can amplify the volume and rate of combustion and thereby raise the process temperature.

The thermal oxidiser 10 can also accept waste water and dirty oil which can be injected 149 into the oxidiser once it reaches its operating temperature, whereby any pollutants are thermally destroyed to steam and combustion products. This is an effective and safe way of 1065 disposing of the small quantities of contaminated liquids generated on site.

DISTILLATION COLUMN

Hot pyrolysed gases convey process heat via a large diameter pipe 68 across to the distillation column, where that heat drives the distillate separation process. The large insulated transfer pipe allows for an efficient transfer of heat and volatiles to the bottom of the column. The 1070 reflux condenser integral with the top of the insulated column has an adjustable cover to allow for fractional cooling control of the 'cut' temperature. This efficient use of process heat saves the energy otherwise required to operate the distillation process (most distillation columns require a separate heating source) and the top end temperature is managed through a fan and temperature sensor to ensure an accurate separation of the distillates.

1075 Fig 9 and 11 : The distillation column 16 functions to receive the gaseous pyrolysate containing a mixture of condensable and non condensable material and to separate this condensable pyrolysate into two fractions of oil with the remaining gas carried over. A separator 25 traps residual water. The distillation column 16 which is an iteration of a well known technology is driven by the heat carried over from the pyrolyser by the volatile gases.

1080 Fig 11 shows a simplified view of one possible embodiment of the distillation apparatus, generally indicated by arrow 16.

Fig 9 is also a simplified schematic view of the distillation apparatus. Preferably, the pyrolysate gases are transferred to the distillation apparatus as soon as they start forming in the pyrolysis tube 3 (i.e. a continuous flow of pyrolysate gases) via a manifolded pipe 68

1085 arrangement. The column distillation trays separate both a light fuel oil fraction and a petroleum white spirits, which may be piped to, and stored in, storage means such as separate holding tanks 70,71. The hot pyrolysate gases enter the distillation apparatus 16 via pipe 68 and provide the column's heat source via the horizontally or vertically mounted lower boil up unit 17 and top mounted reflux condenser 20. Material from the boil up unit 17 is transfer

1090 piped 18 to enter the column at mid-point. The amount of reflux generated by the reflux condenser 20 is controlled by the air flow rate directed through the condenser 20 and provided by a series of fans (not shown).The lower boil up unit 17 is designed to drive the distillates up into the column and collect any heavier residues to a sump from where they are piped out for collection.

1095 The volatile distillates flow upwards via the transfer pipe 18 into the column. Here they commence to separate via distillation by flowing across the surfaces of the many distillation trays (not shown) thereby separating upwards into lighter distillates and downwards into heavier distillates. The heavier distillate fraction (in the case of tyres, "Light Fuel Oil" is obtained) descends over the trays to a separate sump at the bottom of the column adjacent to 1100 the boil up chamber 17. From there the light fuel oil is piped to storage tank 70. The top condenser 20 is adapted to condense and remove the petroleum white spirits fraction, which is piped to the storage tank 71. Non-condensable gases pass via piping 61 to the gasometer 73 or fed to the thermal oxidiser 10, or are drawn into the vacuum system as required, via piping 67.

Fig 9: The distillation apparatus 16 includes flanged sections 19 containing a series of

1105 distillation trays spaced evenly up the length of the distillation tube (trays not shown).

Specially adapted distillation trays may be fitted inside the distillation column whereby the outside of each tray consists of a series of flexible petal-like metal fingers which hold the tray against the inside circumference of the distillation column. The spiral wound pipe of the column has a slightly irregular shape which the flexible fingers of these trays may be able to

1110 grip and maintain the level surface of each tray. Each tray may have a small weir which allows for the condensed fluid to drain past the rising material. The trays may be connected vertically and spaced by threaded rods.

A cooling condenser 23 has a cooling fan and discharge outlet 24; also a number of ¹P' traps 25 to control and separate the outflow of the petroleum white spirits to tank 71, apart from any 1115 water and non-condensable gas. Further processing if required (not shown) of the gases produced can allow for the separation of LPG through chilling and pressure; separation of hydrogen sulphide from the gas through preferential solvent wash; and separation of the remaining the sulphurous compounds using zeolite adsorption.

THE GASOMETER

1120 Fig 11: A gasometer 73 comprises a large, telescoping, cylindrical tank for use as a storage container for gas. One or more may be used with the apparatus described here. The inventors are unaware of any other current pyrolysis systems which incorporate at least one gasometer 73. The advantages associated with using a gasometer are significant. For example, the gasometer may act as a buffer for any pressure differentials; in the event of an emergency or

1125 sudden shutdown of the pyrolysis system, the pyrolysing tyres can take up to 10 minutes to "quieten down" or cease from pyrolysing and the gasometer may receive the pyrolysate gases until they do so; and the gasometer 73 may also act as a general gas receiving and storage facility via pipe 67. Preferably, any gases collected by the gasometer may be piped 67 back to the burner 120 for combustion. Furthermore, the contents of the gasometer may be used to

1130 cold start the pyrolysis system after a shut down. The gasometer water may also absorb some of the sulphur products thereby acidifying the solution. This water can be dosed with sodium bicarbonate to precipitate sulphur as a slurry and balance the pH in the gasometer.

PROCESS CONTROL

A customised method of controlling the plant's operations through the computerisation of its

1135 sequences has been implemented, according to the usual procedures for provision of process control. AU the pneumatic and electrical operations are managed through the use of electronic programmable modules and sensors which are integrated through a programme which monitors, records and directs the plant's equipment for maximum efficiency. The automatic controls can be overridden at strategic points by direct physical human intervention to activate,

1140 operate or disengage any particular piece of equipment, either in isolation or as part of a system e.g. the air switches can be manually operated to open or close the gate valve from two locations.

ADVANTAGES

The advantages of the invention generally and/or improvements over and above prior art of 1145 which we are aware include the following:

1. The pyrolysis system allows for the disposal of used or waste tyres in a safe and/or environmentally acceptable and/or commercially useful manner (the latter being especially true given the economic importance of the recovered oil and carbon for industrial uses).

1150 2. The system uses waste products (e.g. shredded tyres) as its feedstock, generates no residual waste of its own, does not create any pollution, generates its own energy on site, produces reclaimed resources, provides a net gain for landfill space and is built from recycled shipping containers as the main structures. Therefore the plant is demonstrably a green technology which exemplifies the environmental principles of

1155 reduce, reuse, reclaim, recycle.

3. The pyrolysis plant as an engineering system demonstrates significant innovations which sets it apart from other pyrolysis plants. It is configured vertically for efficient gravitational movement of its throughput, it has many unique features incorporated throughout its loading, unloading, heating, cooling, vacuum, gas management and 1160 processing equipment. These unique features in combination constitute a total pyrolysis plant with saleable outputs, which has its solid foundations in the coking furnaces of yesteryear, has the computerised controls, sensors and data management of today and with its modular construction can be customised to handle the pyrolysis requirements of tomorrow.

1165 4. Use of gases generated onsite for the vacuum control of oxygen levels in the entry and exit chambers is done to minimise risk of explosive gas mixtures entering the pyrolysis tube. This is accomplished using a vacuum pump and a three-stage flush process for gas control around the incoming and outgoing materials at either end of the pyrolyser tube. The sequence is air out, flue gas in, flue gas out fuel gas in to load tyres and variations

1170 on this sequence at the exit. AU waste gases are collected after the vacuum pump in a ballast fume tank for feeding into the burner for thermal decomposition. There is no need to purchase purging gas e.g. carbon dioxide or nitrogen because of the onsite supply and the recycled fumes help give better burner performance. Control of the vacuum gases means no fumes are discharged to air in support of the regulatory

1175 consents and constitute an environmentally responsible improvement to the process.

5. The products generated from the plant i.e. solid, liquid and gas pyrolysates have commercial value. They are of suitable quality to be marketed commercially and can be processed to meet specifications required by industry. In addition downstream value added processing can be achieved to isolate particular pyrolysate components e.g. the 1180 tyre carbons can be separated and classified to specification for niche markets; the liquid can be further distilled to select for particular products e.g. solvents; the gas can be stratified to isolate particular chemicals e.g. hydrogen; or some of the products can be used as energy feedstocks for other processes e.g. co-generation of energy from surplus gas.

1585 The construction of the plant offers flexible sizing to meet the requirements of any 'tyre shed', starting from a city about one million people required for the economy of scale to function favourably. Larger cities can support multiple plants located strategically to supply industry with products and to clean up waste tyres which are often gathered in nearby light industrial zones. The modular construction allows sections of the plant to be fabricated elsewhere then

1190 moved to the required location, which due to the vertical positioning of the process containers, will have a smaller footprint than most competing pyrolysis systems.

In conclusion, we should reiterate that the preferred embodiment described above is not limiting as to the scope or range of the invention or its applications.

Claims

1195 I/WE CLAIM

1. A pyrolysis device for heating organic materials to an elevated temperature for a period and thereby causing thermal decomposition of organic materials; characterised in that Has pyrolysis device is comprised of at least one vertically oriented pyrolysis chamber capable when in use of containing a process of pyrolysis; each chamber being thermally

1200 conductive, elongated, and slightly flared so as to be wider towards the base; each chamber having attached thereto an input valve means including air exclusion means, and an output valve means also including air exclusion means, and means to convey a gaseous pyrolysate through an at least partial purification means and to convey a controlled amount of the purified pyrolysate to a thermal oxidiser capable of burning the purified pyrolysate within

1205 an external heating chamber surrounding the at least one vertically oriented pyrolysis chamber.

2. A pyrolysis device as claimed in claim 1 , characterised in that the input valve means comprises a first airlock chamber; the airlock chamber having a first openable gas- tight sealing means between the exterior and the airlock chamber, and a second openable

1210 gas-tight and heat-resistant sealing means after the airlock; the airlock including evacuation means capable of withdrawing air from a charge of organic material placed within the airlock and then of replacing the air with a substantially oxygen- free gas.

3. A pyrolysis device as claimed in claim 2, characterised in that the second heat- resistant sealing means after the first airlock chamber and preceding the pyrolysis chamber

1215 includes an aperture, a closing means, and aperture surrounding means including cooling means directed to the aperture edges employing at least one cooled fluid, and seal protection means in the form of a sleeve which, when in the lowered position, protects the seals from exposure to uprising process heat.

4. A pyrolysis device as claimed in claim 1 , characterised in that the pyrolysis 1220 chamber is provided with means capable of providing for over-pressure relief using alternate channels each terminated by a rupturable diaphragm.

5. A pyrolysis device as claimed in claim 1, characterised in that the pyrolysis device is provided with at least one compliant gas storage means or gasometer for the storage of flammable gases

1225 6. A pyrolysis device as claimed in claim 1 , characterised in that the output valve of the pyrolysis chamber comprises a second airlock chamber; the airlock including a operable char withdrawal means capable when in operation of controllably removing the solid residues of pyrolysate from the pyrolysis chamber above and into the second airlock chamber; a first sealing means adjacent the pyrolysis chamber and a second sealing means 1230 adjacent a solids withdrawal means.

7. A pyrolysis device as claimed in claim 6, characterised in that the operable char withdrawal means comprises a cylindrical mechanical device located beneath an open lower end of the at least one vertically oriented pyrolysis chamber; the withdrawal means being capable of being revolved from time to time, and bearing at least one protrusion

1235 capable of engaging with solid pyrolysate and like material and of breaking apart said solid pyrolysate and causing the solid pyrolysate to fall on to a closed, horizontally retractable door of sliding valve means comprising the first openable sealing means of the second airlock chamber.

8. A pyrolysis device as claimed in claim 6, characterised in that the operable 1240 char withdrawal means comprises a linear mechanical device located beneath an open lower end of the at least one vertically oriented pyrolysis chamber; the withdrawal means being capable of being withdrawn away from the open lower end from time to time, thereupon allowing the solid pyrolysate to fall on to a closed horizontally retractable door of sliding valve means comprising the first sealing means of the second airlock chamber.

1245 9. A pyrolysis device as claimed in claim 6, characterised in that the solid pyrolysate is recovered from the second airlock chamber through a second openable sealing means thereof and held within an environment from which air is excluded until the solid pyrolysate has been cooled sufficiently for combustion in air to be not possible.

10. A pyrolysis device as claimed in claim 9, characterised in that the environment 1250 from which air is excluded comprises a transport means selected from a range including a closed container, an auger operated inside a cowling, and a conveyor operated inside a cowling; said transport means being flushed with cooled flue gases obtained from the heating chamber.

11. A pyrolysis chamber as claimed in claim 1 ; characterised in that the input 1255 valve means and the output valve means are each provided with a first connecting means or pipe controlled by a first valve and leading to an evacuated container, and a second pipe controlled by a second valve and leading to a source of flue gas having a low concentration of oxygen, and a third pipe controlled by a third valve and leading to a source of flammable gas having a low concentration of oxygen, so that any air initially present is substantially 1260 replaced by a gas having a low content of oxygen and so that fumes collected from the valve means are conveyed into the evacuated container for disposal.

12. A thermal oxidiser as claimed in claim 1 ; characterised in that the thermal oxidiser is capable of serving to dispose of, by flaring off, unwanted flammable gases and the enclosing heating chamber is provided with temperature regulation means comprising

1265 temperature measurement means and means capable of admitting and stirring cold air within the chamber in an event of excess temperature caused by a flaring event.

13. A pyrolysis device as claimed in claim 1 ; characterised in that the pyrolysis device, and the associated distillation column, are each provided inside an up-ended shipping container and thereby is modular and capable of replication for the purpose of

1270 expansion, or for the purpose of providing for maintenance.

14. A method of operating a sealed pyrolysis device for heating organic materials to an elevated temperature for a period and thereby causing thermal decomposition of organic materials in a substantially continuous manner; characterised in that the method includes the steps of stepwise admission of a feedstock into the input valve means and stepwise

1275 release therefrom, after flushing free of air, of the feedstock into the pyrolysis chamber which is maintained in a substantially full state; and after pyrolysis has occurred at a known temperature and for a known period of time in an air-free atmosphere, of controllably causing release of the slumped solid pyrolysate from the output valve means into a contained space, substantially free of air, for cooling and subsequent recovery.

1280