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Title:
CONTINUOUS PYROLYSIS APPARATUS
Document Type and Number:
WIPO Patent Application WO/2013/095163
Kind Code:
A1
Abstract:
Apparatus for pyrolysis of industrial waste; vehicle components as car floc and shredded tyres. A hollow centre auger moves material upward through a sealed, sloping tubular furnace heated externally, while evolved liquids drain down along internal grooves. Material is admitted through an evacuable air lock and solids are expelled through a second evacuable air lock; maintaining an absence of air from the non-evacuated furnace interior. An optional second auger moves cooling flammable material along an optional cooled tube. Evolved combustible gases and oils may be used to heat the furnace and maintain pyrolysis.

Inventors:
BELL ALEC COLIN (NZ)
Application Number:
NZ2012/000235
Publication Date:
June 27, 2013
Filing Date:
December 13, 2012
Export Citation:
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Assignee:
VULCAN PYROTECH LIMITED (Unit 2, 11 Weza Lane, Kumeu 0841, NZ)
International Classes:
C10B47/44; B09B3/00; C10B53/00; F27B9/32
Domestic Patent References:
WO1993020396A1
WO2008058137A2
Foreign References:
US5705035A
Attorney, Agent or Firm:
ENSOR, Donald, Rivers (111 Western Springs Road, Mt Albert, Auckland 1022, NZ)
Download PDF:
Claims:
l/WE CLAIM

1. Apparatus (100) for separation by pyrolysis of an amount of material into residual materials including non-combustible components, carbonaceous material, and combustible oils

540 and gases; in which a first hollow centre auger (101) is capable of being rotated in order to move material along an interior of an elongated cylindrical sealed furnace or reaction vessel (102) having a first admission end and a second discharge end and the reaction vessel has at least one port allowing removal of gaseous products of pyrolysis and having an interior capable of receiving external heat (127) along a heatable zone (127B), characterised in that the

545 reaction vessel (102) is oriented so as to slope upward from the first end when in use; and the reaction vessel includes at least two laterally separated and elongated inwardly directed ridges (207) extended along the inner and lower aspect of the reaction vessel (102); each ridge having a raised, exposed surface capable when in use of supporting an external surface of the auger (101); an at least one valley (205), (206) between said at least two ridges serving as at least one channel

550 along which liquid products of pyrolysis may be drained during use towards at least one dependent conduit (124 A) thereby allowing removal of said liquid products.

2. Apparatus as claimed in claim 1, characterised in that the reaction vessel (102) has no means for direct evacuation and when in use, is not directly evacuated.

3. Apparatus as claimed in claim 2, characterised in that a first evacuable chamber or 555 admission air lock assembly (111) comprising a first evacuable space (H ID) preceded by a sealable entry valve assembly (111A) and followed by a sealable exit valve assembly (1 11B) is connected to the reaction vessel (102) at the first end, and a second evacuable chamber or discharge air lock assembly (1 13) comprising a second evacuable space (113D) preceded by a sealable entry valve (113 A) and followed by a sealable exit valve (113B) is connected to the 560 reaction vessel (102) at the second end.

4. Apparatus as claimed in claim 3, characterised in that post-pyrolysis materials cooling means is included; said cooling means comprising a cylindrical vessel (1 12) closed at a first end and having external cooling means (121C), (114) and containing a second rotatable auger (112A) and is arranged so that a first receiving aperture of the vessel (112) at the first end is

565 sealably contiguous with the sealable exit valve (113B) of the discharge air lock assembly (113) and a second delivery aperture of the vessel (112) at a second end is placed above a receiving vessel (115).

5. Apparatus as claimed in claim 3, characterised in that a receiving vessel (1 15) is placed adjacent the sealable exit valve (1 13B) of the discharge air lock assembly (1 13).

570 6. Apparatus as claimed in claim 3, characterised in that the second evacuable chamber at the second end of the reaction vessel includes in the walls thereof external cooling means (121D).

7. Apparatus for separation by pyrolysis of an amount of material into residual materials including non-combustible components, carbonaceous material, and combustible oils and gases, characterised in that a plurality of units, each according to Fig 1 (as la with lb) are 575 operated in proximity such that at least one plant optimised for production of syngas from pyrolysis of hydrocarbon-rich materials supplies syngas for heating an adjacent plant optimised for pyrolysis of hydrocarbon-poor materials; thereby providing a complementary set of units.

SUMMARY

580 Apparatus for pyrolysis of industrial waste; vehicle components as car floe and shredded tyres.

A hollow centre auger moves material upward through a sealed, sloping tubular furnace heated externally, while evolved liquids drain down along internal grooves. Material is admitted through an evacuable air lock and solids are expelled through a second evacuable air lock; maintaining an absence of air from the non-evacuated furnace interior. An optional second

585 auger moves cooling flammable material along an optional cooled tube. Evolved combustible gases and oils may be used to heat the furnace and maintain pyrolysis.

Description:
TITLE: CONTINUOUS PYROLYSIS APPARATUS

FIELD

The invention describes apparatus and a method of use for pyrolysis of organic materials including without limit car floe, rubber, plastics, medical materials, wood and mixed materials; wherein most or all derived products are captured for further use.

DEFINITIONS

"Pyrolysis" is the chemical process of decomposition under the effect of heat, pyrolitic, adj.

In the present invention, the preferred end products include carbon (char) and therefore "pyrolysis" is preferred over "incineration" which is defined as the chemical process of oxidation under the effect of heat, so converting material to oxidised ashes.

"Car floe" is a term describing the mainly organic materials removed from vehicles during wrecking and includes plastics, rubber, fibrous materials, upholstery and the like as well as electronics and wiring. In this document it is regarded as separate from rubber tyres.

"Syngas" is a term for a flammable hydrocarbon gas mixture derived from pyrolysed organic waste and scrubbed or purified to a required extent.

BACKGROUND

Many inventions exist for relatively effective yet economical disposal of vulcanized rubber vehicle tyres. Yet the value in performing pyrolytic separation of wastes can be greater in other areas, for example "car floe". Effective and pollution-free pyrolysis or alternatively incineration is desirable. Possible volatile pollutants include for example hydrochloric acid, volatilised plasticisers, and other toxic byproducts.

Literature review. Examples of published patents having closed, sealed; low-emission, elongated furnaces having air exclusion means at a materials inlet include US2006/0211899 (compresses the tyres to exclude air) US2004/0182001, US7416641 (nitrogen plus heat), US 4900401 and US 4648328 (simple exclusion). Examples describing closed, elongated furnaces that do not include air exclusion include GB2475671 and US 7416641. Examples describing closed, elongated evacuated furnaces for pyrolysis include WO2011/010323, WO2011/008075, and EP08531 14. Examples having closed, elongated inert-gas filled furnaces for pyrolysis include GB 2303859. EP 0070040 describes a 0.4 to 1.5 Bar hydrocarbon vapour atmosphere within the reaction vessel, and uses an inert purge gas at a rotary air lock (page 29). Like GB2475671, EP 0070040 describes a hollow auger. WO 98/14531 describes input and output ports that are evacuable, and the entire pyrolysis chamber is also evacuated (p5 lines 34-35). PROBLEM TO BE SOLVED

There is a need to provide a pyrolysis apparatus which converts material such as tyres into usable byproducts yet which is cheap and effective. The market lacks small installations; existing large ones are uneconomic to acquire. It may be more effective to run several small machines in parallel; more or less of them as the demand dictates, rather than one large machine.

OBJECT

An object of the present application is to provide a cheap yet effective pyrolysis apparatus for converting organic waste; particularly though not exclusively manufactured materials into usable byproducts, or at least to provide the public with a useful choice. The term "manufactured materials" includes used tyres, car floe and scrap metals including organic contaminants.

SUMMARY OF INVENTION

Suitably shredded material is imported into a furnace, the reaction vessel, through a chamber which has an entry door and an exit door and the interior of which chamber can be evacuated as part of a "Receiving Cycle" in which material but not air is admitted into the furnace. The atmosphere within the reaction vessel while operating may contain hydrocarbon vapours that serve to help carry heat to the material to be pyrolysed as well as being drawn off as a useful and flammable output. Solid char, ash and nonflammable material is exported from the furnace through a second chamber, also operated in combination with a vacuum pump so as to prevent air (oxygen) from being admitted into the furnace.

Example 1 will describe a version optimised for shredded rubber vehicle tyres as the predominant material to be treated by pyrolysis. This is a well-known feedstock. Other feedstocks resulting in char or carbon are processed in an Example 1 version of the invention. Example 2 will describe a version optimised for shredded "car floe"; a name for a mixture of organic material, wiring, interior furnishings, rubber and plastic parts derived from wrecked vehicles intended for recycling purposes as the predominant material to be treated by pyrolysis.

Example 3 will describe a version optimised for cleaning up scrap metal, such as electrical wiring comprised of copper surrounded by insulation material, or vehicle radiators as the predominant material to be treated by pyrolysis.

In a first broad aspect the invention provides apparatus for separation by pyrolysis of an amount of material into residual materials including non-combustible components, carbonaceous material, and combustible oils and gases; in which a first hollow centre auger 101 is capable of being rotated in order to move material along an interior of an elongated cylindrical sealed furnace or reaction vessel 102 having a first admission end and a second discharge end and the reaction vessel has at least one port allowing removal of gaseous products of pyrolysis and having an interior capable of receiving external heat along a heatable zone, wherein the reaction vessel 102 is oriented so as to slope upward from the first end when in use; and the reaction vessel includes at least two laterally separated and elongated inwardly directed ridges 207 extended along the inner and lower aspect of the reaction vessel 102; each ridge having a raised, exposed surface capable when in use of supporting an external surface of the auger 101 ; an at least one valley 205, 206 between said at least two ridges serving as at least one channel along which liquid products of pyrolysis may be drained during use towards at least one dependent conduit 124 A thereby allowing removal of said liquid products.

In a first related aspect, the reaction vessel 102 has no means for direct evacuation and when in use, is not evacuated.

In a second related aspect, the first evacuable chamber or admission air lock assembly 1 11 comprises a first evacuable space 11 ID preceded by a sealable entry valve assembly 111 A and followed by a sealable exit valve assembly 11 IB is connected to the reaction vessel 102 at the first end, and a second evacuable chamber or discharge air lock assembly 113 comprising a second evacuable space 113D preceded by a sealable entry valve 113A and followed by a sealable exit valve 113B is connected to the reaction vessel 102 at the second end; said air lock assemblies being capable when in use of maintaining an effective absence of air from the interior of the reaction vessel 102.

In a first major option, the apparatus is provided with post-pyrolysis materials cooling means suitable for the pyrolysis of materials that are converted into an amount of carbon or char, comprising a cylindrical vessel 112 closed at a first end and having external cooling means 121C, 114 and containing a second rotatable auger 1 12A and is arranged so that a first receiving aperture of the vessel 1 12 at the first end is sealably contiguous with the sealable exit valve 1 13B of the discharge air lock assembly 113 and a second delivery aperture of the vessel 112 at a second end is placed above a receiving vessel 115.

In a second major option, the apparatus is used with materials likely to result in a small amount only of carbon or char, wherein a receiving vessel 115 is placed adjacent the sealable exit valve 1 13B of the discharge air lock assembly 113

In a third option at least some of the cooing functions of the post-pyrolysis materials cooling means comprises inclusion in the walls thereof external cooling means such as water circulating pipes 12 ID, or fins, or forced air cooling.

In a first broad aspect the invention provides apparatus for separation by pyrolysis of an amount of shredded material into residual materials including non-combustible components, carbonaceous material, oils and gases; in which a first hollow centre auger is capable of being rotated in order to move shredded material along an interior of a sealed, cylindrical furnace or reaction vessel having a first waste admission end and a second solids expulsion end and having an interior capable of receiving external heat along a heatable zone, characterised in that the reaction vessel is oriented so as to slope upward from the first end when in use; a first evacuable chamber comprising a first evacuable space preceded by a sealable entry valve and followed by a sealable exit valve is connected to the reaction vessel at the first end, a second evacuable chamber comprising a second evacuable space preceded by a sealable entry valve and followed by a sealable exit valve is connected to the reaction vessel at the second end; said sealable valves being capable when in use of maintaining an absence of air from the interior of the reaction vessel which is not directly evacuated, and the reaction vessel includes at least two laterally separated and elongated strips extended along the inner and lower aspect of the reaction vessel; each strip having a raised, exposed surface capable when in use of supporting an external surface of the auger; the separation between said at least two strips providing at least one channel along which liquids may be drained during use towards at least one dependent valve allowing removal of liquid products of pyrolysis.

Preferably the reaction vessel has at least one valve allowing removal of gaseous products of pyrolysis.

Optionally some removed combustible gases or oils are burnt to heat the reaction vessel and maintain pyrolysis.

Optionally heat is supplied from other forms of gas including syngas, LPG, CNG, and methane from bio-reactors, or from an electric heating means at least for starting a process.

Preferably the heatable zone of the reaction vessel is heated to a temperature of between about 180 deg C and about 650 deg C, depending on the material being processed.

Preferably at least a portion of the reaction vessel of the pyrolysis apparatus is contained within a thermally insulating casing so that, when in use, heat derived from the gas burner is conserved.

Optionally burnt gases are trapped and the heat within the burnt gases is used to dry material awaiting admission to the pyrolysis space. Preferably the second evacuable chamber of the reaction vessel includes in the walls external cooling means selected from a range including conduits capable of carrying circulating cooling 130 liquid that are in thermal contact with the second evacuable chamber, fins thermally attached to the second evacuable chamber that are capable of dissipation of heat from within the container, a blackened exterior, and forced air movement means capable of dissipating at least some heat from the materials within.

In one option, a non-sealed, cylindrical container is provided, and contains a second rotatable 135 auger and is arranged so that a first receiving aperture of the container at a first end is sealably contiguous with the sealable exit valve of the second evacuable chamber and a second delivery aperture of the container at a second end is placed above a receiving vessel.

Preferably the cylindrical container includes in the walls thereof external cooling means selected from a range including conduits capable of carrying circulating cooling liquid that are in thermal 140 contact with the second evacuable chamber, fins thermally attached to the second evacuable chamber that are capable of dissipation of heat from within the container, a blackened exterior, and forced air movement means capable of dissipating at least some heat from the materials within.

In a second broad aspect the reaction vessel is provided with a quenching water or gas supply which can be admitted into the space within in an emergency.

145 Optionally the reaction vessel is provided with a safety valve capable of releasing internal pressure in a controlled manner in the event of an internal over-pressure event or explosion.

In a second broad aspect, the non-sealed, cylindrical container having external cooling means is not included as for scrap metal reclai where little if any hot char is released from the reaction vessel.

150 Alternatively, the second and non-sealed, cylindrical container capable of being cooled externally contains a second rotatable hollow centre auger and is arranged so that a first receiving aperture of the container at a first end is contiguous with the sealable exit valve of the second evacuable chamber and a second delivery aperture of the container at a second end is placed above a receiving vessel.

155 Optionally the reaction vessel has a vertically elongated oval cross-sectional shape thereby providing some space above the auger for redistribution of materials being transported.

In a major option, a second and non-sealed, cylindrical container capable of being cooled externally contains a second rotatable auger and is arranged so that a first receiving aperture of the container at a first end is contiguous with the sealable exit valve of the second evacuable 160 chamber and a second delivery aperture of the container at a second end is placed above a receiving vessel.

Preferably conduits or a jacket capable of carrying circulated water are in contact with the second cylindrical container in order to assist with cooling of selected portions of the apparatus or of materials carried within.

165 Preferably the output port includes means either internal to the evacuated space or subsequently for dissipating sufficient heat from the materials so that on exposure to air, emission of volatile materials does not occur.

In a second broad aspect, since each individual plant as shown in Fig 1 (a and b) is relatively small and cheap, it may be optimal to run several plants together and regard each one as a 170 module complementing the other modules.

In a related aspect, a plurality of units (Figs la and lb) are operated in proximity such that at least one plant optimised for production of syngas from pyrolysis of hydrocarbon-rich materials (for example tyres or shredded parts thereof) supplies syngas for heating an adjacent plant optimised for pyrolysis of hydrocarbon-poor materials (for example car floe or scrap metal); 175 thereby providing a complementary set of units.

In another related aspect, a plurality of tyre plants are used in parallel, thereby allowing any one plant to be stopped for maintenance or repairs while production continues in the others.

PREFERRED EMBODIMENT

The description of the invention to be provided herein is given purely by way of example and is not to 180 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 not the exclusion of any other integer or step or group of integers or steps. Each document, reference, patent application or patent cited in 185 this text is expressly incorporated herein in their entirety by reference. Reference to cited material or information cited in the text should not be understood as a concession that the material or information was part of the common general knowledge or was known in New Zealand or in any other country.

DRAWINGS

190 Fig 1 : (as Fig la and Fig lb; the drawing divided into two parts) shows a simplified diagram of the pyrolysis apparatus.

Fig 2a: shows detail of a cross section of the reaction vessel.

Fig 2b: shows detail of a cross section of an alternative form of the reaction vessel.

Fig 3: shows the core less auger used as the internal conveying means.

195 Fig 4: shows a cross section of the reaction vessel, including the thermal shield and chimney.

Fig 5: shows more detail of a version of the char cooling and separation portion. EXAMPLE 1

See the simplified diagram 100 in Fig 1. This diagram has been cut into two (Figs la and lb) along the dashed vertical line in order to fit the portrait-orientation page. Fig 1 shows, 200 diagrammatically, a working embodiment of the invention.

The pyrolysis apparatus of the invention 100 is based on an closed and sealed pyrolysis space; the reaction vessel 102 which has a shape of a long cylinder. Inside the reaction vessel there is a materials transport device preferably comprising a coreless auger (as shown in Fig 3 as 101) traversing the space and pushing material from the waste adm ission end at the left of Fig 1 through 205 the central heated zone inside the reaction vessel and towards a solids discharge end of the vessel.

Motor 103 drives the auger. The Example 1 version for tyre shreds is used in association with a second cooling tunnel 1 12 in which discharged, hot material is carried by an auger through a low-oxygen atmosphere while being cooled since hot material may burn if in contact with air immediately after discharge. Low-carbon Examples may not require that second tunnel.

210 INLET AIR LOCK. Chopped car or other vehicle tyres shredded into strips each preferably no larger than about 15 to 50 mm long and 15 mm wide are placed onto a first or intake conveyor system, which is drawn here as a simple vertical hopper 110 to be manually filled from time to time. The intake conveyer transfers the product toward the waste admission end of the reaction vessel 102 through the inlet air lock 111, which is operated according to a programmed sequence.

215 In this machine, the reaction vessel 102 is maintained free of oxygen, or at least substantially so.

It will be noted that the invention does not include means for evacuation of the reaction vessel 102. Substantial freedom from gaseous oxygen within 102 is achieved by a sequential operation of the inlet air lock assembly 111 and also of the discharge air lock assembly 113, including the step of evacuation of each air lock chamber 11 ID and 113D during transit of material. Note that

220 sequential operation of either airlock is independent of the other. The admission air lock comprises an evacuable space 11 ID about 300 mm in diameter and 400 mm high, preceded by a sealable entry slide valve driven by pneumatic actuator 111 A under a hopper and followed by a sealable exit valve driven by pneumatic actuator 11 IB.

A sequence for operating the inlet air lock assembly 111 starts with the chamber H ID in 225 between the initially closed valves likely to hold some reaction vessel hydrocarbon gas after a previous cycle. First, this gas is at least partly evacuated by the vacuum system through pump 135, using the valve 132A in pipe 132 (preferably through an inlet filter to prevent ingress of dust), and pumped into a cooled gas receiver 121. Then the inlet slide valve 1 1 1A is opened and a charge of material falls in. Then the inlet slide valve is closed, and the chamber 1 1 ID is 230 evacuated, again through the vacuum control valve 132A. In this phase, chamber evacuation may proceed toward a lower pressure. After evacuation is complete, the outlet slide valve 11 IB is opened and the material becomes exposed to the reaction vessel atmosphere while falling on to the transport auger 101 (see Figs 2, 3 and 4). Finally the outlet slide valve 11 IB is closed again. A relatively insignificant amount of oxygen will be admitted into the vacuum 235 system along with each charge of the incoming organic material. In case of inclusion of unburnt oxygen, the later gas purification means 128 may include a liquefaction stage or the like to ensure that only hydrocarbon gases are retained for later combustion, for instance in burner 127.

The discharge air lock assembly 113 is operated in a similar way (see later) as pyrolysed 240 materials pass between reaction vessel 102 and a cooling cylinder 112. The discharge air lock comprises an evacuable space 113D about 300 mm in diameter and 400 mm high, preceded by a sealable entry valve 113 A under a collection space and followed by a sealable exit valve 113B.

All slide gates themselves are preferably Tyco (USA) parts F952-12 sliding valves with Teflon ® seals; 12 inches (about 300 mm) diameter, pushed or pulled by pneumatically driven pistons (Tyco) 245 with a slide time of typically 10 seconds. It should be noted that this type of sliding valve does not have a requirement to equilibriate the pressure on each side of the valve before it is opened, unlike the air locks in the cited W098/14531 Joynes.

VACUUM PUMP AND PIPING. A rotary vacuum pump 135 connected, for example, through 50 mm diameter reinforced-wall pipe 131 that includes an in-line filter assembly (not shown) to 250 the incoming side air lock 111 through branch 132, and to the discharge air lock 113 through line 134.; each through a controlling vacuum valve 132A and 134A (Burkert DN 50 P25) located close to the airlock chamber. The vacuum pump shall be capable of handling mixed vapours arising from either airlock chamber including some that are liable to condense on to working surfaces of the pump. It may be desirable to heat the pump so that this does not happen. In fact, the 255 preferred Edwards GV80F rotary vacuum pump which is driven by a 4 kW motor requires water cooling, thereby overcoming that risk. In practice, the amount of remaining oxygen in the reaction vessel is expected to be about 1% of the concentration in air at sea level, depending on timing, sealing efficiency and outgassing, and the extent to which any oxygen if present can immediately react with reducible materials. Normally the inlet and the outlet air locks are not

260 operated at the same time. Note that the pump does not evacuate the reaction vessel 102.

AUGER. Preferred materials for making the auger 101 which is shown in Figs 2a, 2b, 3 and 4 include mild steel, and carbon steel. A coreless auger is preferred over an auger with a central shaft or core. It allows better convection and includes some flexibility in the event that some material becomes caught against an inside of the reaction vessel. The auger diameter in the

265 prototype is 300 mm; the pitch is 300 mm, and the auger is comprised of a spirally deformed 100 x 21 mm strip metal. The auger and the entire reaction vessel may be scaled up for example to a 600 mm diameter auger. The auger is supported on the inside of the reaction vessel— see the details in Figs 2a and 2b. The auger is made to rotate within the space by a motor and reduction gearbox 103. There is a thrust bearing and a gas seal at the base of the auger. The auger 101

270 causes the material being pyrolysed to be continuously pushed along the length of the reaction vessel 102 from the inlet airlock 111 past a heated zone above burner 127 while the auger turned (typically at or around 10-16 rpm, depending on the materials to be processed) within the cylinder. Since the pitch is nominally 300 mm and the reaction vessel is typically 6 metres long, it follows that 20 revolutions of the auger or 1.25-2 minutes is a minimum transit time in which material

275 may reach the discharge airlock 113. Note that practical testing is not yet in progress and experimentation with different materials over different periods is awaited. The motor 103 is preferably a separate motor with a reduction gearbox placed to one side of the reaction vessel, driving a sprocket attached to the auger through a chain drive. Then, on-site sprocket wheel selection allows speed changes in response to the material being processed. Also, the length of the reaction vessel

280 102 and auger 103 within can be changed if a higher throughput is required.

REACTION VESSEL and HEATED ZONE. The cylinder of the reaction vessel 102 is at a slope upward from the admittance end both to manage hot gas, and to make use of gravity as an assistance for movement of liquids within the reaction vessel. A preferred slope is believed to be about 5-10 degrees; preferably about 7 degrees with the auger pushing materials upward from 285 the inlet. Oil drains down towards the inlet end, to the left of Fig 1, through pipe 124 A, and into oil tank 124. Valve 124C may in practice include a pump as well, in the event that pressure inside the reaction vessel 102 is negative with respect to the pressure inside tank 124 - typically atmospheric pressure. Oil fractionation or other separation may be applied as imposed by market needs for instance.

290 The wall of the reaction vessel 102 as shown in cross-section in Fig 2a and in Fig 2b is a cylindrical tube of bare metal such as 6 mm mild steel, or stainless steel. Partial thermal insulation 128 of rock wool coats the reaction vessel 102 except above the gas burner array at 127B where external hot gas is in contact with the wall. In this embodiment a space of 50 mm surrounds the steel wall of the reaction vessel, beneath the rock wall insulation 128, in the

295 region over the burner 127. The discharge end of the reaction vessel may not require insulation and might be deliberately cooled since the flammable material to be discharged may commence cooling before release. The minimum internal diameter of the prototype example is 320 mm, assuming a 300 mm diameter auger. The free space above the auger helps with internal convection. In one option as shown in Fig 4, the cylinder is not round, but elliptical although

300 preferably the lower part of the ellipse may have a part-circular profile to contain the auger, as shown in the cross-sections Figs 2a and 2b. An elliptical tube is relatively expensive to make, as compared with circular tubes. Rarely, an explosive material may be inadvertently ignited and the space above the auger will help with instantaneous pressure dissipation and re-distribution of combustion products. The safety or overpressure valve 102B releases pressure shocks from the

305 reaction vessel. The auger 101 may become bent or warped in time as a result of operating conditions or repeated heating and cooling. The relative lack of constraint along the auger sides renders the invention tolerant of auger bending. The wall 102 is required to have sufficient strength under heat to hold its shape during use, where parts are heated up to from about 180 deg C to about 600 deg C, depending on the material being processed, while the internal pressure may

310 be between about 0 Bar to about 1.5 Bar, again depending on the material. Note that in this invention, unlike much of the prior art, the atmosphere inside the reaction vessel is not continuously evacuated and in order to exclude oxygen, air is simply not admitted. Conduction, convection and radiation convey heat through the chipped or granulated material which may be tumbling while moved by rotation of the coreless auger 101.

315 Optionally, some of the hot gases in the chimney 129 may be led around the outside of the intake hopper within a heat exchanger (not shown) in order to supply heat and warm the material to be pyrolysed, in particular to drive off any water. A section through the reaction vessel is shown in Fig 4, including an external insulated manifold 128 around and spaced apart from the cylinder 102. The space contains hot burnt gas. A chimney 129 for disposal of combustion products may also

320 include means for scrubbing the exhaust of sulphur dioxide. Fig 4 also shows a support frame 130. This invention includes a series of perhaps two to six elongated metal strips 204 fixed internally along the length of the lowest part of the interior of the sloping reaction vessel 102, as shown in the cross-section Fig 2a. The strips may be square-section mild steel about 1-2 cm square and reach along the reaction vessel from about the position of liquid drain pipe 124A to the aperture 325 for access to the discharge airlock assembly 113. The strips slidingly support the coreless auger 101 by its circumference, and also provide drainage channels 205 to lead oil and other liquids towards an extraction valve located at the lowest (inlet) part of the furnace. Otherwise the rotating auger and materials shifted by the auger tend to move that oil up and to the far end of the reaction vessel. The areas of sliding friction are lubricated by recovered oil during use.

330 As a preferred alternative to fastening strips within the tube, the lower part of the sloping tubular reaction vessel 102 may be deformed as shown in Fig 2b to form a series of longitudinal corrugations along the lower, inner surface of the tube of the reaction vessel 102 along the same length as the strips described above, to simulate the strips. The valleys 206 of the corrugations serve as channels for flowing liquid and the peaks 207 serve as bearing

335 surfaces for the auger. The corrugations also stiffen the tube. To make this version, a plain steel tube 102 is cut in half lengthwise, the lower half is deformed by cold or hot pressing or a type of rolling, and the two parts of the tube are then welded together at 208 (a section through one bead). The internal diameter of the finished tube should be enough to accommodate the rotatable hollow auger 101 even if the auger becomes somewhat distorted over time. Groove

340 numbers and dimensions may be established with experience; Fig 2b is an illustrative diagram only.

HANDLING EVOLVED LIQUID AND GAS. The inventor expects about 70-80 kg of a syngas equivalent to be produced per hour of use when pyrolysing tyres at an expected rate of 80 shredded tyres per hour, and also expects about 300 litres per hour of oil which can be processed into a fuel 345 for diesel engines that can be used alone or blended with standard diesel fuel. Note that using an increased reaction vessel temperature raises the proportion of gas, and a lower temperature raises the proportion of oil. Application of a higher temperature by the process operator will tend to convert oil into smaller hydrocarbons such as gases, so the operator can modify the ratios of the preferred residue according to current demand and prices.

350 The oil or heavy oil that runs along the channels to the bottom of the reaction vessel 102 drains through pipe 124 A into a bulk storage tank 124 through valve or pump 124C. The vacuum pump 135 exhaust which is likely to contain a small proportion only of the oil and gas is led through condensing tank 121 that is cooled by pipes 120A and 120B. Liquid condensed within that tank drains through valve 12 IB into tank 124. It may be necessary to heat tank 124, to overcome 355 viscosity. The oil may be used instead of syngas in the apparatus in burners 127, or may be cleaned and processed such as by distillation or fractionation to be used as diesel or marine fuel. The selected use will depend on instant markets, and on convenience. In the present apparatus no fractionation devices are included, but such devices, being well-known in the relevant art, may be added later. The oil storage vessel 124 is provided with an outlet tap or pipe capable of 360 releasing stored liquid materials from time to time for an appropriate use.

Syngas is drawn from the reaction vessel through collecting tube 133 leading through valve/pump 133 A to condenser 121 which is cooled with water or even chilled water. The chilled water is supplied through pipe 120A, and returned through pipe 120B from a tank 120 of recirculatable water (for which refrigeration means, if any, is not shown). Preferably the cooling water is

365 forced to circulate by a pump 120C. The condenser 121 may be an actual heat exchanger, or may be a vessel having an externally cooled surface as condensing means. The design should allow for automatic draining of heavy condensate carried with the syngas, which will affect withdrawal of heat and may block internal spaces. Optionally the condenser 121 will allow occasional dismantling, inspection and cleaning. Valve/pump 133A may be needed to overcome pressure

370 differences during operation. The pressure inside the reaction vessel, expected to be between about 0.5 Bar and 1.5 Bar, is dependent on a rate of evolved gases.

Syngas drawn from the condenser 121 is cleaned or purified by gas processing means 128 and then stored in a gas storage tank 126. Preferably gas has been cleaned such as in unit 128 before consumption in the external gas burner 127. It is likely that sulphur-containing materials will be

375 collected from vulcanized tyres. It is undesirable to release sulphur dioxide into the surrounding environment. It may be simpler to trap the products of combustion from the chimney at 129 and scrub any sulphur oxides at that point, using for example lime or zeolites. In a diesel or like oil fuel, note that sulphur is a useful lubricant. One example of a gas processing means cools and compresses the syngas into a liquid which can be stored as such under pressure. The stored

380 syngas, held in vessel 126 is likely to be reserved for heating the reaction vessel 101 although an outlet tap or pipe, with valve 126B for exporting gas is shown. 126 may be a type of gasometer. Recycling gas within the pyrolysis machine provides low-cost heating energy.

At start-up and as an option, the gas burner can also be run on previously stored syngas or LPG, CNG or any other burnable gas. An oil burner may be used, depending on where the pyrolysis 385 machine is located and depending on the material being pyrolysed. Electric heating may be employed. For some types of organic waste pyrolysis, the yield of syngas is not self-supporting and another supply of heat is required.

AIR LOCK (DISCHARGE). The apparatus shown in Fig lb includes a second or discharge air lock assembly 113 and char cooling, char transport, and char separation devices which are based

390 on an external out-feed conveyor that receives pyrolysed materials from the reaction vessel through the discharge airlock assembly 1 13. The residue from pyrolysed tyres results in a hot carbonaceous char/steel wire mix that is transferred to the discharge end of the pyrolysis chamber 102 by the coreless conveyer 101 and enters discharge air lock assembly 113 by falling into side tube 113C against slide gate assembly 1 13 A. In the usual cyclic process, the gas in the interior

395 113D of the airlock is first evacuated though valve 134A and pipe 134 leading to vacuum pump 135 so that the gas is retrieved and so that no oxygen can be admitted into the reaction vessel 102. Then, slide gate 1 13A is opened by a piston actuator in the same manner as for the inlet air lock 111, conditional on the lower slide gate 113B still being closed at that time. After an amount of hot char/steel mix has entered the airlock, slide gate 113A is closed and slide gate 113B is then

400 opened, allowing the hot char to fall out of the airlock. Note that part or all of the discharge air lock assembly 113, and perhaps especially the slide valve seals may be cooled directly by piped water circulating in pipes or in a jacket in contact with the exterior.

COOLING TUBE; HANDLING EVOLVED SOLIDS. See Fig 5 and Fig l b. This optional component of the invention comprises post-pyrolysis materials cooling means since any carbon-rich

405 char requires to be cooled to below an ignition temperature when exposed to air. (In some cases the invention will be used to pyrolyse car floe or scrap metals having a small amount only of carbon-yielding components). At this point the hot char/steel wire mix is partially cooled, having already left the heated zone inside the reaction vessel 102 and having passed through air lock assembly 113, but may still be hot enough to combust in air. Accordingly, further steps are

410 preferably taken, especially in Example 1 , to cool the material before it is exposed to air.

Valve 113B of discharge air lock assembly 113 opens and drops the hot char/steel mix into the out feed conveyer tube 112 inside jacket 114, and then closes. Another auger 112A, likely to be one with a solid centre and driven continuously so as to move material to the right by a motor with gearbox 112B is shown here. The out feed conveyer is substantially immersed in oxygen- 415 deficient air, but is not at this point of development run under vacuum. The objective is to have cooled the char before exposing it to air. In Fig 5, the auger 112A will be turned inside the out feed conveyer tube or cylindrical vessel 112 that is surrounded by and cooled by the water jacket 1 14 carrying water pumped from tank 120 by pump 120C (see Fig 1) through inlet 121 A then to outlet 12 IB, so to absorb heat emitted from the char/steel mix and retard combustion. (In Fig 1 the same water cooling was shown as an optional spiral pipe 121 C). Auger movement stirs the char.

Optionally a cool, oxygen-free and non-reactive gas is allowed to replace the vacuum and equalize the pressure inside the airlock 113D, such as bottled nitrogen from container 113F via valve 1 13E, or carbon dioxide from burner exhaust gas. Water or steam may be introduced into the chamber 113D as a suitable quenching material but provision must be made for environments where water is scarce. This replacement action reduces ingress of air into the external out-feed conveyor or cylindrical vessel 112 when valve 113B is opened and exposes a partly-filled evacuated space. Alternatively if the hot char/steel mix packs well into the space it simply displaces gas and there is little suction of air through the out feed conveyer tube 112 at that time.

In an optional version, the airlock chamber 113D is elongated by an amount sufficient to hold a quantity of cooling char/steel mix and its walls are also provided with a water jacket or attached pipes as described above. If sufficient cooling is assured before opening of the outlet slide gate 113B, the admitted gas may be air. In that case the water jacketed assembly 121C and indeed the entire conveyor 1 12 may be deleted and instead char separation means 117, which delivers carbonaceous material into container 116 and steel or other non-pyrolysed hard objects into container 115 is placed below the discharge air lock assembly 113. Readers familiar with the relevant arts will know of several existing options for char and metals separation, such as hammering or rolling to shatter the brittle char into granules, followed by magnetic recovery of steel wire. For example, the char separation means 117 (not shown in detail) of this Example may compress the hot char between optionally water-cooled metal rollers or plates to help extinguish any lingering combustion. After crushing, the char mixture from tyres is a black friable powder mixed with fragments of magnetic wire, which may be retrieved by sieving, magnetic separation, or any other convenient means. One well-known alternative is to incorporate a permanently magnetized surface on the surface of a crushing roller, so that magnetic material is picked up as the roller rotates. The adherent steel can then be scraped off the magnetized roller after it has turned away from the carbon fraction. Another option is to use an electromagnet to pick up the steel fragments from the crushed char. Inadvertently included glass or other nonflammable solids may be removed by sieving.

Note that although in the prototype the physical dimensions of the discharge air lock chamber 113D are the same as those of the inlet air lock (an evacuable space about 300 mm in diameter and 400 mm high) the discharge airlock may be made smaller in specific applications once the amount of shrinkage in volume of the now pyrolysed material is established. For rubber tyres, the shrinkage is large, but for car floe or scrap metals (see later Examples) there may be no benefit in reducing the size and hence volume of the outlet air lock. Indeed, longer retention times within this air lock may be useful as a stage in cooling.

455 PLANT CONTROL MEANS. (NO DRAWING) The apparatus should be tolerant of operation by inexperienced personnel. There is a mixture of continuous (auger-based) and cyclic (airlock-based) operations that should operate at an overall coordinated rate. Therefore an overall automatic controller is preferred; one that can be set up with a minimum of commands in order to execute disposal of a known type of material to be incinerated or pyrolysed. Preferably the

460 preferred PLC (Process logic cycle) controller is provided with sufficient sensors to detect most if not all possible hazardous states as well as process status measurements - including the position of materials - and includes logic flow or analysis means for taking appropriate action by means of actuators, since an infrequently used operator will not be reliable in an emergency. Ideally, an attendant simply needs a "Start" and a "Stop" button, and will work to keep a supply of material up

465 to the input hopper and ensure that none of the oil storage tank 124, the gas storage tank 126, or solids containers 115 and 1 16 are overfilled. Preferably overload cutouts are included, so long as halting one function does not adversely impact on other functions. Fail-safe or emergency control means may be required, such as a quenching fluid; for example bottled fire suppressant, nitrogen or carbon dioxide, even water, for admission into the reaction vessel. This may be required

470 as part of a start-up procedure, in case structural or valve failure admits air into the interior, or in case a fire develops. Preferably the quenching fluid is stored under pressure so that it will always be forced into the reaction vessel 102.

The pyrolysis temperature may be regulated by (for example) electronic sensing means responsive to infra-red radiation from the walls of reaction vessel 102, using a control valve 127 A along the 475 gas supply line to control flame size and hence temperature.

The whole plant is operated by a standard programmed logic control (PLC) system with appropriate interfaces to pneumatic or hydraulic valves, and includes safety systems and features which are operated by temperature and pressure switches throughout the machine. A largely or completely "pneumatic environment" will be preferred.

480 At starting up, which may take 30 minutes, the furnace interior may be simply cycled, or flushed with carbon dioxide or nitrogen in order to exclude air, or the entire interior may be evacuated or otherwise rendered substantially free of oxygen by running the vacuum pump for a sufficient period of time with one or both doors from air lock chambers into the reaction vessel open.

485 EXAMPLE 2

This Example is optimised for pyrolysis of shredded "car floe" as defined previously in this document. Expected differences include that a hotter pyrolysis temperature will decarbonise the solid materials, of which aluminium, copper and steel are likely to be the most valuable. In one

490 mode, any hot carbon that is expelled is intended to burn, and the cooling arrangements are relaxed. Car floe may not support its own pyrolysis with sufficient syngas and external heating may be needed, such as by using syngas from an adjacent pyrolysis unit, also according to the invention, that is processing shredded tyres. Alternatively, the expelled products are cooled and then rolled or hammered in order to disintegrate the char. The products are then sieved in order

495 to separate granular char from metals, glass and ceramics.

EXAMPLE 3

This version is optimised for cleaning up scrap metal, such as electrical cables comprised of copper surrounded by insulation material, or vehicle radiators as the predominant material to be treated by pyrolysis. The main difference from Example 2 is that less organic material is 500 expected. Scrap metal is unlikely to support its own pyrolysis with syngas and external heating may be needed, such as syngas from an adjacent pyrolysis unit (se Example 4). Useful byproducts include metals such as copper, brass, and aluminium.

EXAMPLE 4

Each individual plant as shown in Fig 1 (a and b) is relatively small and cheap. In some 505 installations it may be convenient to run several plants together and regard each one as a semi- independent module. For example, a first plant may be adjusted for optimal production of syngas from tyres. Surplus syngas from that plant may be used for heating an adjacent plant adjusted for optimal conversion of car floe into usable fractions. That arrangement might suit a car wrecker. In another example, five equivalent tyre plants are used in parallel and there is 510 sufficient flexibility as a result of the number to allow any one plant to be stopped for maintenance while production continues in the others.

VARIATIONS

Disposal of wood, such as demolition timber possibly containing nails, arsenic and copper; disposal of contaminated organic waste such as hospital infectious waste, can be carried out in a 515 similar way. Perhaps such wastes and shredded tyres can be mixed together. Scrubbing of evolved gases to remove volatilised arsenic would be advisable.

RESULTS AND ADVANTAGES This invention uses heat in the absence of oxygen to extract useful components from waste material, such as rubber waste from vehicle tyres, while disposing of the tyres themselves. The 520 products produced may be fuels, or inputs into an organic synthesis perhaps making plastics. Any selected specific use is a function of current demand. Steel wire can be sold as scrap, as per normal recycling. Removal of organic materials associated with metals, such as insulation from copper wire, enhances the value of the metal such as the copper as scrap.

The channels along the bottom of the reaction vessel also serve to increase the area available for 525 heat transfer from the external flame a little like fins, raising heating efficiency.

Char has many economic uses including being processed and pelletized as a fuel, being used in cement works, in the manufacture of toner, for extraction of toxic materials by adsorbtion, or in fertilizers or the like.

This invention is relatively small in physical size and in capital cost, as compared to the prior art. 530 The invention can be placed on a truck bed or on a trailer and moved from site to site. That would be applicable in countries where separate towns have separate dumps. Otherwise the invention can be permanently installed alongside a business, such as a vehicle wrecker.

Finally it will be understood that the scope of this invention as described and/or illustrated herein is not limited to the specified embodiments. Those of skill will appreciate that various 535 modifications, additions, known equivalents, and substitutions are possible without departing from the scope and spirit of the invention as set forth in the following claims.