WO2012021917A1

WO2012021917A1 - Method and apparatus for treating materials

Info

Publication number: WO2012021917A1
Application number: PCT/AU2011/000879
Authority: WO
Inventors: Struan Glen Robertson
Original assignee: Struan Glen Robertson
Priority date: 2010-08-16
Filing date: 2011-07-13
Publication date: 2012-02-23
Also published as: AU2011236014B1

Abstract

Apparatus for treating waste product which contains waste gases, the apparatus comprising a feed system, a retort having a treatment chamber therein for receiving the waste product, a first discharge outlet for discharging gaseous waste and particulates from the retort treatment chamber and a second discharge outlet from which treated solids and liquids can be discharged from the retort treatment chamber, a particulates treatment vessel for receiving gas and particulates from the retort treatment chamber and a catalytic reactor device for the treatment of gases discharged from the particulates treatment vessel.

Description

METHOD AND APPARATUS FOR TREATING MATERIALS

Technical Field

This invention relates generally to the treatment of materials including waste solids, liquids and gases, including toxic waste and municipal waste, by way of example only.

Background Art

Waste materials are produced in many technological fields. The treatment of these waste materials has become an important issue in recent years. Not only is there a desire to render such materials safe but there is a continuing striving to try and produce valuable products from the waste.

Summary of the Invention

According to one aspect there is provided an apparatus for treating waste product which contains waste gases, the apparatus comprising a feed system, a retort having a treatment chamber therein for receiving the waste product, a first discharge outlet for discharging gaseous waste and particulates from the retort treatment chamber and a second discharge outlet from which treated solids and liquids can be discharged from the retort treatment chamber, a particulates treatment vessel for receiving gas and particulates from the retort treatment chamber and a catalytic reactor device for the treatment of gases discharged from the particulates treatment vessel.

In certain embodiments the retort and particulate treatment vessel are at least partially surrounded by a combustion chamber so that the temperatures within the retort treatment chamber and the particulate treatment vessel are substantially the same. Further, in certain embodiments the catalytic reactor device includes a reactor vessel which is at least partially surrounded by the combustion chamber. Preferably, the apparatus includes a single outlet line which combines the solids from the retort chamber and the particulates output from the particulates treatment vessel. Preferably, the particulates treatment vessel forms part of the retort and is structurally integral therewith.

The feed system may include a solids feed mechanism and a separate liquids feed mechanism. A pretreatment device including a dewatering system may be provided upstream of the feed system. The dewatering system may be heated by waste gases from the combustion chamber. The material being fed to a feed hopper of the feed system may be passed through a sizing device such as a grate to remove oversized solids and foreign materials. The apparatus is preferably configured so as to be substantially free of oxygen. If considered appropriate however a nitrogen purge may be provided to substantially keep the waste product oxygen free. One or more pressure relief valves may be provided for the apparatus. Furthermore, the apparatus may include a gas treatment system downstream of the catalytic reactor.

In another aspect, there is provided a method for extracting product from materials fed into the apparatus described above, the product being extracted simultaneously in the form of gas from the catalytic reactor device and solids and particulates waste generated from the treatment chamber during continuous processing of the material through the apparatus.

According to another aspect, there is provided a feed system for apparatus of the type described above, the feed system comprising a solids feed mechanism which includes a feed hopper which may be in the form of a lock hopper, a transfer conduit for receiving material from the feed hopper the transfer conduit having a transfer zone spaced from the feed hopper, a feed conduit for receiving material from the transfer zone, a first plunger associated with the transfer conduit for transferring material from the feed hopper to the transfer zone and a second plunger associated with the feed conduit for transferring material to the retort along the transfer conduit. The plungers bend to compact the material prior to it being fed to the retort treatment chamber. In certain embodiments the first plunger is adapted to isolate the feed hopper from the transfer zone when the first plunger is moved towards the transfer zone. The second plunger may be adapted to isolate the transfer zone from the feed conduit as the second plunger moves along the feed conduit towards the retort. The feed system may further include a press for urging material from the feed hopper to the transfer conduit. A second press may be provided which is adapted to urge material from the transfer zone into the feed conduit.

In certain embodiments a liquids feed device may be provided which is separate from the solids feeds mechanism for enabling the transfer of liquid to the retort. The liquids feed device may include a pump for delivering liquid waste material to the retort treatment chamber.

According to yet another aspect there is provided a retort for use in apparatus as described above, the retort comprising a treatment chamber having a generally cylindrical shaped inner side wall and an upstream end and a downstream end, an inlet at the upstream end for receiving material from the feed system, a solids outlet at the downstream for discharging treated solids from the treatment chamber and a gas and particulates outlet at the downstream end for transferring gases and particulates contained in those gases to the particulates treatment vessel.

Preferably, the retort includes the particulates treatment vessel, formed integrally with and fixed in relation to the retort to separate particulates from gases generated within the retort, the particulates treatment vessel having an outlet for the particulates arranged so as to combine the particulates with the solids output through the solids outlet. In certain embodiments the retort may further include a material transfer device which causes the agitation and travel of material within the treatment chamber from the upstream end to the downstream end. The transfer device may include an upstream section and a downstream section which are spaced apart to provide for a dwell space therebetween. Preferably each of the transfer devices comprises a helically configured ribbon-like element mounted to a rotatable shaft which extends between the upstream and downstream ends of the treatment chamber.

According to yet another aspect there is provided a particulate treatment vessel for use in apparatus as described above, comprising a main body which is at least partially surrounded by combustion chamber and having a treatment chamber therein, an inlet for delivering particulates and gases from the retort treatment chamber to a lower end of the particulates treatment chamber, an outlet for the discharge of particulates from the chamber and a gas outlet for the discharge of gases from the chamber.

According to yet another aspect there is provided a gas treatment system as described above, comprising a pressurised chamber for pressurising the gases and having a feed inlet for delivering hydrogen through the pressurised chamber and a catalytic reactor downstream of the pressurised chamber which causes a reaction between the gases and the introduced hydrogen and metals contained in the catalytic reactor.

Brief Description of the Drawings

Notwithstanding any other forms which may fall within the scope of the methods and apparatus as set forth in the Summary, specific embodiments will now be described, by way of example, and with reference to the accompanying drawings in which:

Figure 1 is a schematic illustration of apparatus according to one embodiment;

Figure 2 is a schematic illustration of a retort which can be used in the apparatus shown in Figure 1 ; Figure 3 is a schematic illustration of a feed system which is suitable for use in the apparatus shown in Figure 1; Figure 4 is a schematic illustration of a particulate treatment vessel suitable for use in the apparatus shown in Figure 1 ; and

Figure 5 is a schematic illustration of a gas treatment system suitable for use in the apparatus shown in Figure 1.

Detailed Description of Specific Embodiments

Referring to Figure 1, the apparatus 100 comprises a feed mechanism 10 including a solids feed device 1 1 and a liquids feed device 13. The solids enter inlet line or conduit 12 and liquids enter inlet line or conduit 14. The solids feed device 1 1 is illustrated in Figure 3 and will be described in more detail later. The liquids feed device 13 includes a pump 16 in the form of a mono pump for pumping the liquids to along the inlet line or conduit 14.

The apparatus further includes a fixed and non-rotatable retort 30 comprising a treatment chamber 32 which is surrounded by a combustion chamber 36. The material to be treated enters the treatment chamber from upstream end 39 and is caused to travel to the downstream end 41. The retort 30 will be described in more detail later with reference to Figure 2. The apparatus further includes particulate treatment vessel 50 comprising a treatment chamber 54 at least partially surrounded by a heat jacket or combustion chamber 52. A delivery conduit 56 transfers the gasses and particulates from the retort treatment chamber 32 to the treatment chamber 54. Solids are discharged from the treatment chamber 54 via line 57. Gases treated in the vessel 50 pass to a plenum 58 which in turn transfers the gases to the gas treatment system 70. Particulates in the vessel 50 are discharged along line 61, together with solids from the retort 30. Accordingly, the discharge outlet of the apparatus 100 combines the retort solids discharge and the filtered particularates discharge, both forms of discharge being generated by the continuous processing of material through the fixed and non-rotating retort 30. The gas treatment system 70 comprises an induction fan 72 for drawing the gases from the treatment chamber 54 and directs them to a pressurising chamber 74 from which they pass through a hydrogenation chamber and a catalyst chamber 78.

Referring now to Figure 3, there is illustrated a solids feed mechanism 1 1 comprising a feed hopper 18 for feeding solid material to be treated into a transfer conduit 26 which has a transfer zone 27 at its downstream end. A press 19 ensures the constant flow of material to transfer conduit 26. Prior to depositing material into the feed hopper 18 it may be passed through a grate or other suitable sizing system so as to remove oversized solids of foreign materials. Furthermore, the feed materials may be pre-treated in a dewatering device using oils heated by waste energy from the retort combustion chamber to a temperature that dewaters the feed material thereby drying the materials ready for the retort.

The mechanism further includes a plunger 20 which pushes and compacts material within the transfer conduit 26. The plunger 20 is configured so that it sealingly closes the conduit past the hopper 18 providing an air tight arrangement. Desirably, the feed materials need to be fed in with little or no oxygen so a nitrogen purge may be required to keep the feed stock air free. By utilizing a plunger the materials are compacted for feeding into the retort thereby reducing the amount of oxygen in the feed stock and thus reducing the need for nitrogen.

Material in the transfer zone 27 at the end of the transfer conduit 29 is then transferred to a feed conduit 28 by means of press 22. When press 22 is activated, plunger 20 is in a position wherein the feed hopper 18 is isolated from the transfer conduit 29 thereby ensuring that there is no substantially ingress of oxygen into the conduits. A further plunger 24 is arranged to move along the feed conduit 28 thereby urging the material into the retort.

Referring now to Figure 2, there is illustrated a retort 30 having a cylindrically shaped side wall 34 with a treatment chamber 32 therein. Material from the feed mechanism enters the chamber 32 via inlet 39 which directs the material towards the centre of the chamber 32. A device 41 is provided in the region of the inlet to break up material entering the chamber 32. A material transfer device 43 causes material to travel from an upstream end of the chamber 32 to a downstream end. The transfer device comprises an upstream section 42 and a downstream section 44 with a space 46 therebetween. As shown, the transfer device 43 is formed of helically configured blades operativeiy connected to a rotatable shaft for rotation therewith. The angle and orientation of the blades ensures the material is lifted to the retort with each sweep, as well as moving the material from the front to the back with each movement. This is important as the retort 30 is fixed so the materials have to be moved along as well as exposed to the retort walls, which greatly enhances the heat transfer ratio, to ensure release of volatiles.

A combustion chamber 36 surrounds the side wall of the treatment chamber 32. Burners 28 heat the gases within the combustion chamber. The burners 28 are configured within a hollow ceramic chamber which extends from the upstream to the downstream ends of chamber 32. At the downstream end the ceramic heating chamber exits the combustion chamber via a discharge stack. These gases can be used to heat oils for use in the dewatering system discussed above. There are a series of burners mounted within the ceramic chamber to ensure the equal distribution of radiant and convection heat through the retort wall. The combustion chamber may also be refractory lined to provide radiant and convection heat in the combustion chamber.

The retort is disposed at an angle which assists the materials to move towards the downstream end under the influence of gravity. The materials are pushed upwards and sideways so as to maximise the materials repeated interaction with the side wall which is generally 200 to 300 degrees hotter than the retort bed temperature. The retort process bed temperature is kept constant by the continual introduction of materials for processing and the downstream end of the retort chamber which has a lip 33 to introduce a reverse flow thereby increasing the resonance time. The lip 33 at the downstream end of the retort extends about half the distance between the agitation device shaft and the bottom of the retort thereby the materials are forced to feed over the lip and in doing so creates the slight negative flow that increases the resonance time.

The resonance time is a function of removing all the volatiles from the materials by way of an increased heat transfer ratio which is brought about by the number of evenly spaced rivets breaking up and distributing the materials for processing. With the radiating heat device surrounding 60% of the retort this gives a greatly improved heat transfer ratio without impinging the materials of construction. The retort itself can be made of the appropriate steels or of a moulded ceramic chamber which would greatly increase the resistance to chemical reactions and improve the life of the retort walls. At the end of the retort chamber halfway between the agitation shaft and the top of the retort a duct 37 mounted across the entire top of that one half of the retort to allow the process of gases/volatiles to flow into the particulate treatment vessel 50. Just prior to that duct there is an angled grate 31 attached to the top of the retort wall to deflect some of the particulates from the gas outlet. These particulates would combine with the residual processed solids that would drop out of the bottom of the retort into a rotary valve 47 which would ensure that the inert atmosphere is maintained. A series of nozzles 49 provide for a water spray which reduces the creation of dust as the solids pass to a pugmill.

As shown in Figure 4 the particulates treatment vessel 50 comprises a main body 55 with a treatment chamber 54 therein. The main body is partially surrounded by a heat jacket or combustion chamber 52 which in the embodiment shown is formed by the retort combustion chamber; that is the main body 55 is at least partially disposed within the retort combustion chamber. This ensures that the two treatment chambers are at about the same temperature. Indeed, the main body 55 can, in fact, be structurally integral with the retort 30 or in effect be part of the retort 30. Particulates and gases from the retort treatment chamber are passed to the treatment chamber 54 via delivery conduit 56 having an inlet at the bottom of the treatment chamber. A baffle 57 deflects particulates towards the lower end of the vessel and gases pass around the baffle to enter the main part of the chamber 54. A grate 59 inhibits the passage of solids into the vessel. A metal frame 61 is mounted within the main part of the chamber and is adapted to support a flexible membrane which collects particulates while permitting the passage of gases therethrough. The membrane resemble a bag and may be made of carbon ceramic or other suitable materials. The gases travel towards the top of the vessel into a plenum 64. A pulsing device 65 extends into the chamber for the delivery of an inert gas such as nitrogen which causes the particulates to be dislodged from the membrane in order to clean it. Particulates collect at the bottom of the chamber and are discharged through outlet 67 via rotary valve 68.

The chamber may also comprise a number of ceramic candles (now shown in the illustrated embodiment) which can also be used to remove particulates from the gas. The candles can also have associated therewith a pulsing device which utilises nitrogen to release particulates from the sides of the candles.

Referring to Figure 5, the gas treatment system 70 includes an induction fan 72 which draws gases from the plenum 64. The fan is constructed so as to be able to be used over a wide temperature range. The gases are then compressed by a compressor and enter a pressurised chamber 74. The gases in the pressurised chamber are hydrogenated before passing to a catalytic reactor 78. The reactor 78 contains base metals suitable to cause a reaction between the gases, the introduced hydrogen and the metals. The hydrogen molecules are transferred to the gases so as to upgrade them thereby providing a higher valued condensate. A valve 79 in the form of a slidable gate is arranged to change the pressure within the reactor. This controls the exposure of the gases to the catalyst metals. A further reactor 80 is disposed downstream of the reactor 78 to assist in further upgrading of the gases. The or each catalytic reactor may be disposed within a combustion chamber.

The gases which are discharged from the reactors are ready for fractionisation, distillation or condensing. The condensed gases may be high value oils low in the higher carbon ranged offering a greatly increased yield of high value products.

It should also be appreciated the apparatus 100 can operate to continuously process material, as opposed to many prior art arrangements which operate on a batch processing basis. Also, the retort 30 and treatment vessel 50 are fixed relative to one another, as compared to prior art retorts which are rotatable. This allows for considerable simplification of construction as, for example, engineering tolerances and thermal plugs associated with rotating components are not required. In addition, the retort 30 and vessel 50 can be formed with an integral structure or housing and, indeed can share a common combustion chamber to maintain substantially equal temperature which provides manufacturing and cost savings. Lastly, the apparatus 100 allows for what is essentially a single or simultaneous stage processing of both solids, gases and particulates in the one apparatus, which substantially simplifies processing.

In the foregoing description of preferred embodiments, specific terminology has been resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "front" and "rear", "above" and "below" and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in th field of endeavour to which this specification relates. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", 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.

Finally, it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements of parts without departing from the spirit or ambit of the invention.

Claims

Apparatus according to claim 1, wherein the retort and particulate treatment vessel are at least partially surrounded by a combustion chamber so that the temperatures within the retort treatment chamber and the particulate treatment vessel are substantially the same.

Apparatus as claimed in claim 1, including a single outlet line which combines the solids from the retort chamber and the particulates output from the particulates treatment vessel.

Apparatus as claimed in claim 3, wherein the particulates treatment vessel forms part of the retort and is structurally integral therewith.

Apparatus according to claim 2, wherein the catalytic reactor device includes a reactor vessel which is at least partially surrounded by the combustion chamber.

Apparatus according to any preceding claim, wherein the feed system includes a solids feed mechanism and a separate liquids feed mechanism.

Apparatus according to any preceding claim, including a pretreatment device including a dewatering system.

8. Apparatus according to claim 7, wherein the dewatering system is heated by waste gases from the combustion chamber.

9. Apparatus according to any preceding claim, wherein the apparatus is configured so as to be substantially free of oxygen.

10. Apparatus according to any preceding claim, including one or more pressure relief valves.

11. Apparatus according to any preceding claim, including a gas treatment system downstream of the catalytic reactor.

12. A method for extracting product from materials fed into the apparatus of any one of claims 1 to 1 1, the product being extracted simultaneously in the form of gas from the catalytic reactor device and solids and particulates waste generated from the treatment chamber during continuous processing of the material through the apparatus.

13. A feed system for apparatus according to any one of claims 1 to 11, the feed system comprising a solids feed mechanism which includes a feed hopper, a transfer conduit for receiving material from the feed hopper the transfer conduit having a transfer zone spaced from the feed hopper, a feed conduit for receiving material from the transfer zone, a first plunger associated with the transfer conduit for transferring material from the feed hopper to the transfer zone and a second plunger associated with the feed conduit for transferring material to the retort along the transfer conduit.

14. A feed system according to claim 13, wherein the first plunger is adapted to isolate the feed hopper from the transfer zone when the first plunger is moved towards the transfer zone.

15. A feed system according to claim 13 or 14, wherein the second plunger is adapted to isolate the transfer zone from the feed conduit as the second plunger moves along the feed conduit towards the retort.

16. A feed system according to any one of claims 13 to 15, further including a press for urging material from the feed hopper to the transfer conduit.

17. A feed system according to any one of claims 13 to 16, further including a second press which is adapted to urge material from the transfer zone into the feed conduit.

18. A feed system according to any one of claims 13 to 17, further including a liquids feed device separate from the solids feeds mechanism for enabling the transfer of liquid to the retort.

19. A retort for use in apparatus according to any one of claims 1 to 11, the retort comprising a treatment chamber having a generally cylindrical shaped inner side wall and an upstream end and a downstream end, an inlet at the upstream end for receiving material from the feed system, a solids outlet at the downstream for discharging treated solids from the treatment chamber and a gas and particulate outlet at the downstream end for transferring gases and particulates contained in those gases to the particulates treatment vessel.

20. The retort is claimed in claim 19, wherein the retort includes the particulates treatment vessel, formed integrally with and fixed in relation to the retort to separate particulates from gases generated within the retort, the particulates treatment vessel having an outlet for the particulates arranged so as to combine the particulates with the solids output through the solids outlet.

21. A retort according to claim 19, further including a material transfer device which causes the agitation and travel of material within the treatment chamber from the upstream end to the downstream end.

22. A retort according to claim 19 or 21, wherein the transfer device includes an upstream section and a downstream section which are spaced apart to provide for a dwell space therebetween.

23. A retort according to any one of claims 19 to 22, wherein each of the transfer devices comprises helically configured blades mounted to a rotatable shaft which extends between the upstream and downstream ends of the treatment chamber.

24. A particulate treatment vessel for use in apparatus according to any one of claims 1 to 11, comprising a main body which is at least partially surrounded by combustion chamber and having a treatment chamber therein, an inlet for delivering particulates and gases from the retort treatment chamber to a lower end of the particulates treatment chamber, an outlet for the discharge of particulates from the chamber and a gas outlet for the discharge of gases from the chamber.

25. A gas treatment system for use in apparatus according to any one claims 1 to 1 1, comprising a pressurised chamber for pressurising the gases and having a feed inlet for delivering hydrogen through the pressurised chamber and a catalytic reactor downstream of the pressurised chamber which causes a reaction between the gases and the introduced hydrogen and metals contained in the catalytic reactor.