EP2958976A1

EP2958976A1 - Improvements in waste processing

Info

Publication number: EP2958976A1
Application number: EP14701614.1A
Authority: EP
Inventors: Rifat Al Chalabi; Ophneil Henry Perry
Original assignee: Chinook End Stage Recycling Ltd
Current assignee: Chinook End Stage Recycling Ltd
Priority date: 2013-02-19
Filing date: 2014-01-27
Publication date: 2015-12-30
Also published as: WO2014128432A1; GB201302840D0; TW201500107A; GB2510901B; GB2510901A

Abstract

This invention proposes an apparatus for pyrolysing or gasifying material containing an organic content. The apparatus comprises an oven (10) mounted for rotation on at least one support (12, 14). The oven (10) comprises a main processing chamber (16) for heating the material in a low or zero oxygen atmosphere to gasify or pyrolyse its organic content. A secondary processing chamber (18) for receiving processed material from the main processing chamber (16) is also provided. An eddy current separator (22) is positioned adjacent or in the secondary processing chamber (18) and is located such that as the oven rotates, material in the second processing chamber repeatedly passes it. The eddy current separator (22) is orientated such that, in use, it ejects non-ferrous metals from the secondary processing chamber (18).

Description

Improvements in Waste Processing

This invention relates to the pyrolysis and/or gasification of material, in particular of material such as municipal solid waste containing a mixture of organic material and metals.

Gasification and pyrolysis of organic matter are known techniques in which the material is heated in the absence of oxygen (pyrolysis) or in a low oxygen environment (gasification) to produce syngas. One example of this is in waste to energy systems wherein waste material, for example municipal solid waste, is pyrolysed/gasified to produce syngas which is then used to create electricity. However when material having a large amount of organic material with a low calorific value, for example wood (in contrast to materials such as plastics which have a high calorific value), is pyrolysed a carbonic residue remains together with inert ash like materials and the non organic matter, e.g. glass, metal etc. The carbonic residue is a char or coke like substance referred to collectively herein as char.

After the pyrolysis reaction is complete this char still contains a recoverable energy, which can be recovered through gasification reactions in which oxygen is consumed. These take place at high temperatures and due to the temperature and the oxygen present tend to oxidise any metals present within the remaining material. This degrades the metal which, if preserved in good condition can be recovered and recycled. Accordingly systems that perform these processes are running at a lower than may be expected total efficiency as either the energy is trapped in the char, or the recoverable high value meals (e.g. aluminium) become oxidised and are either non recyclable or have their value significantly degraded due to the oxidation.

It is the purpose of the present invention to provide an improved apparatus and method of processing waste.

According to the present invention there is provided an apparatus for pyrolysing or gasifying material containing an organic content, comprising an oven mounted for rotation on at least one support, wherein said oven comprises: a main processing chamber for heating the material in a low or zero oxygen atmosphere to gasify or pyrolyse its organic content; a secondary processing chamber for receiving processed material from the main processing chamber; an eddy current separator positioned adjacent or in the secondary processing chamber and located such that as the oven rotates, material in the second processing chamber repeatedly passes said eddy current separator; wherein the eddy current separator is orientated to, in use, eject non-ferrous metals from the secondary processing chamber.

As the apparatus separates the non ferrous metals from the processed material, the remainder of the processed material can then be gasified without oxidising the non ferrous metals. Generally the non ferrous metals, for example aluminium, copper, brass etc are the metals having a high monetary value as recycled metals and accordingly if these can be separated then the most valuable materials are prevented from becoming oxidised. Once the non-ferrous metals have been separated, hot gas (in excess of 300° C) containing a low level of oxygen (up to 12% mass flow) can be introduced into the secondary processing chamber to gasify the char therein to release carbon monoxide

A selectively openable gate may be provided between said main processing chamber and said secondary processing chamber. This prevents material passing from the main processing chamber into the secondary processing chamber before processing I the main processing chamber is complete.

The apparatus may further comprise a separation chamber and the eddy current generator can be located to eject non-ferrous metals into the separation chamber. In one arrangement the secondary processing chamber may be adjacent the main processing chamber. In another arrangement the secondary processing chamber may be separated from the main processing chamber by the separation chamber.

The apparatus may further comprise an electromagnet located such that the material within the oven passes said electromagnet as the oven rotates, said electro magnet for the separation of ferrous metals from the processed material.

In this manner the ferrous metals can be separated from the processed materials. AS they pass the electromagnet they will become attracted thereto and be separated from the remainder of the processed material. Preferably this is done prior to the separation of the non-ferrous metals so that there is no magnetic interactions between the ferrous metals and the eddy current separator.

In one arrangement the electromagnet is provided in one of: the main processing chamber, the secondary processing chamber, or the separation chamber. If provided in the main processing chamber the ferrous metals can be separated at the end or during the main processing cycle before the processed material transfers into the secondary processing chamber. If provided in the separation chamber the material will all be passed into the separation chamber, the oven rotated with the magnet activated to attract the ferrous metals, and then the remainder of the processed material, excluding the ferrous material, can be transferred into the secondary processing chamber, after which the non ferrous metals can be ejected from the secondary processing chamber back into the main processing chamber. If provided in the secondary processing chamber

The apparatus is provided with a means for heating the main processing chamber and for heating the secondary processing chamber. This may comprise the provision of a supply of hot gas to the first processing chamber and the provision of a supply of hot gas to the secondary processing chamber. The supply of hot gas to the secondary processing chamber can have a higher oxygen content than the hot gas provided to the primary processing chamber. The supply of hot gas to the main processing chamber may have substantially no oxygen. In this way the reaction in the main processing chamber can be a pyrolysis reaction that produces syngas and a char and the process in the secondary processing chamber can be a gasification reaction that reacts the char with oxygen to produce carbon monoxide.

The apparatus may include a means of dividing the secondary processing chamber into a first part having the eddy current separator associated therewith and a second part. The means may be a gate or a closable aperture. The hot gas may be provided to the second part of the secondary processing chamber. In this way the eddy current separator is protected from the heat, and the heat is retained in the section of the secondary processing chamber that does not open onto the separation chamber.

According to a second aspect of the invention there is provided a method of pyrolysing or gasifying material containing an organic content and non-ferrous metal, the method comprising: heating, in the main processing chamber of a rotating oven .material containing an organic content to a first temperature in a low or zero oxygen environment to process it to release syngas; transferring said processed material from said main processing chamber to a secondary processing chamber of the oven; and separating the non-ferrous metal from the remainder of the processed material using the eddy current separator.

After completion of the processing of the material in the first processing chamber the method may further comprise: selectively opening a gate between said main processing chamber and said secondary processing chamber; and moving said oven to cause the processed material to pass from the main processing chamber to the secondary processing chamber.

A separation chamber may be provided and the method may further comprise operating the eddy current separator to move the non-ferrous metals into the separation chamber.

The method may further comprise: providing an electromagnet on said oven; and rotating said oven such that the material within the oven passes said electromagnet as the oven rotates such that said ferrous material is separated therefrom. The ferrous material is separated after the material in the main processing chamber has been processed.

The method may comprise heating the material in the secondary processing chamber. The material in the secondary processing chamber may be heated to second temperature higher than the first temperature. The heating may comprise: providing a flow of hot gas to the main processing chamber to heat the material therein in a first stage of processing; and providing a flow of hot gas to the secondary processing chamber to heat the material therein in a second stage of processing. The flow of hot gas to the secondary processing chamber may have a higher oxygen content than the flow of hot gas provided to the primary processing chamber. Preferably the step of separating the non-ferrous metals from the processed material precedes the step of heating the material in the secondary processing chamber. After separating the non-ferrous metals from the material within the second chamber the method may further comprise: dividing the second chamber into a first part having the eddy current separator associated therewith and a second part containing the material; and heating the material in the second part of the secondary processing chamber.

A specific embodiments of the invention are described below, by way of example, with reference to the accompanying drawings, in which Figure 1 is a schematic cross section through an oven of the apparatus;

Figure 2 is a schematic diagram of a valve arrangement of the apparatus; and

Figure 3 is a schematic cross section through an alternative oven of the apparatus.

Referring to Figure 1 a rotating oven 10 of the invention is shown. The oven 10 is rotatably mounted on two supports 12, 14. The oven 10 comprises a main processing chamber 16, a secondary processing chamber 18 and a separation chamber 20. An eddy current separator 22 is mounted adjacent the secondary processing chamber 18 such that the separation force exerted by it on non ferrous metals is in the direction indicated by the arrow A.

In use, material is loaded into main processing chamber 12 the oven 10. This can be done in a number of ways. A openable door may be provided in the oven or a section of the oven 10 may form a removable charging box 24 which can be loaded with the material to be processed and then attached to the remainder of the oven 10. a flow of hot gas is then provided to the inlet 26 which then enters the main processing chamber 12 and exits via outlet 28. The oven 10 rotates on its supports 12, 14 as the material is heated by the flow of hot gas. The hot gas contains substantially no oxygen and has a temperature in excess of 300°C. The organic content of the material pyrolyses and releases syngas containing a mixture of hydrogen and carbon monoxide.

Once all the organic matter is pyrolyses the first step of processing is complete and the flow of hot gas can be stopped. The completion of the pyrolysis reaction can be ascertained by the monitoring of the outlet gas from the main processing chamber 16. When it is sensed that the hydrogen and/or carbon monoxide levels drop below a certain level, or that the change in carbon monoxide and/or hydrogen over time has stabilised then it can be ascertained that the process is complete. The processed material will contain the inorganic content, for example, metals, ceramics, glass etc, inert fully pyrolysed residue and some char which still contains a large amount of carbon.

An electromagnet 32 is then energised and the oven 10 continues to rotate such that the ferrous material is attracted to and magnetically retained by the electromagnet 32 to separate it from the remainder of the processed material. Although depicted at the top of the oven 10 (when it is not rotated) it will be appreciated that the electromagnet 32 can be positioned a any position relative to the main processing chamber 10 providing the material therein passes the electromagnet 32 as the oven rotates. Once the ferrous material has been separated from the remainder of the processed material the a gate 30 which separates the main processing chamber 16 from the separation chamber 20 and the secondary processing chamber 18 is opened. The oven 10 is then pivoted about a pivot bearing 34, and optionally rotated, such that the material in the main processing chamber 12, excluding the ferrous metal, passes through the gate 30 into the secondary processing chamber 18, after which the gate 30 is then closed.

The oven 10 is reverted back to the position shown in Figure 1 and rotates. The electromagnet 32 may be deactivated at this point or may optionally remain on throughout the remainder of the process.

As the oven rotates the eddy current separator 22 is activated such that a force in the direction depicted by the arrow A is exerted on non ferrous metals that pass the separator. These metals, such as aluminium, copper etc. will be forced by the separator through an opening 35 and will pass into the separation chamber 20. Two ramped edges 38 assist in preventing the material (excluding the non ferrous metals) in the rotating oven 10 from passing from the secondary processing chamber 18 into the separation chamber 20 as the oven rotates. In this way the non ferrous metals can be separated from the material in the second processing chamber. When the non-ferrous metals has been separated a second gate 40 in the secondary processing chamber is closed with the material in the bottom of the chamber 18 with the oven substantially in the position as shown in Figure 1. The material is therefore trapped in a processing section of the secondary processing chamber 18 enclosed by the gate 40.

Secondary processing of the char within the material in the secondary processing chamber 18 then commences. Hot gasses containing between 3 and 12% oxygen mass flow rate is then passed through the processing section of the secondary processing chamber 18. The gas has a temperature in excess of 300°C, preferably in excess of 500°C. The temperature and oxygen reacts with the char in a gasification reaction to oxidise it to release carbon monoxide. If steam is also present in the hot gas then the gasification process may also release hydrogen. As the non ferrous metals are isolated from the hot gasses they are protected from the heat and oxygen and do not oxidise. During the secondary processing the eddy current separator 22 may be switched off or optionally may continue to be activated to prevent any pieces of non ferrous metal re-entering the secondary processing chamber 18 as the oven 10 rotates.

The hot gas entering the secondary processing chamber 18 may enter and leave the oven 10 via the same inlet 26 and outlet 28. Referring to Figure 2 a valving arrangement of the oven 10 is shown with the main processing chamber 16 and the secondary processing chamber 18 being connected in parallel and valves 42, 44 and 46, 48 respectively controlling the inlet and outlet flow from the inlet 26 and outlet 28 of the oven 10 to the main 16 and secondary 18 processing chambers. The valves 42, 44, 46, 48 and the conduits between them and the processing chambers can all form part of the oven structure.

As the char becomes fully gasified the carbon monoxide levels and the hydrogen levels, which can be sensed by gas analysers 50, 52 indicate that the process is complete and the process can be stopped.

The fully processed and separated material can then be removed from the oven. The charging box 24 can be detached from the remainder of the oven 10 and the separated materials will be in three different sections thereof, the ferrous material will be in the section that formed part of the main processing chamber 16, the non ferrous metal will be in the section that forms part of the separation chamber, and the inert fully processed residue which will include ash, fully processed organic material residue, and non-metallic non-organic material (e.g. glass, ceramic etc) will be in the part of the charging box 24 that formed part of the secondary processing chamber 18.

The oven may be a drum shaped oven but may also be a substantially rectangular in cross section.

A variation to the design shown in Figure 3 omits the separation chamber 20 altogether. The ferrous material is separated from the material after the main processing is complete by means of the electromagnet 32. The gate 30 is then opened and the material transferred to the secondary processing chamber 18 as detailed above. With the gate 30 open the oven 10a is rotated with the eddy current separator 22 activated to eject the non-ferrous metals back into the main processing chamber 16. The gate 30 is then closed and secondary processing begins. When unloading the oven after completion of the process the electro magnet 32 can be maintained activated until the non-ferrous metals is removed, after which the electro magnet 32 can be deactivated to release the ferrous material.

In other respects the oven and process operate in the same was as described above in relation to Figure 1 and 2. It will be appreciated by the skilled person that the forgoing is an example of the invention only and other embodiments will be apparent to the skilled person. For example the skilled person will understand that the separation chamber 20 is not necessarily located between the main 16 and secondary 18 processing chambers, for example the secondary processing chamber 18 could be located between the main processing chamber 16 and the separation chamber 20. Other modifications will be apparent to the skilled person and are within the scope of this invention, the limitation of which is defined by the claims.

Claims

CLAIMS:

1 An apparatus for pyrolysing or gasifying material containing an organic content, comprising an oven mounted for rotation on at least one support, wherein said oven comprises:

a main processing chamber for heating the material in a low or zero oxygen atmosphere to gasify or pyrolyse its organic content;

a secondary processing chamber for receiving processed material from the main processing chamber;

an eddy current separator positioned adjacent or in the secondary processing chamber and located such that as the oven rotates, material in the second processing chamber repeatedly passes said eddy current separator; wherein

the eddy current separator is orientated to, in use, eject non-ferrous metals from the secondary processing chamber.

2 An apparatus according to claim 1 further comprising a selectively openable gate between said main processing chamber and said secondary processing chamber.

3 An apparatus according to claim 1 or claim 2 further comprising a separation chamber and wherein the eddy current generator is located to eject non-ferrous metals into the separation chamber.

4 An apparatus according to claim 1 or claim 2 wherein the secondary processing chamber is adjacent the main processing chamber.

5 An apparatus according to claim 3 wherein the secondary processing chamber is separated from the main processing chamber by the separation chamber.

6 An apparatus according to any one of the preceding claim further comprising an electromagnet located such that the material within the oven passes said electromagnet as the oven rotates, said electro magnet for the separation of ferrous materials from the processed material. 7 An apparatus according to any one of the preceding claims wherein the electromagnet is in one of the main processing chamber, the secondary processing chamber, or the separation chamber. 8 An apparatus according to any one of the preceding claims further comprising a means for heating the main processing chamber and for heating the secondary processing chamber.

9 An apparatus according to claim 8 wherein the means for heating the main processing chamber and for heating the secondary processing chamber comprise means for providing a supply of hot gas to the first processing chamber and for providing a supply of hot gas to the secondary processing chamber.

10 An apparatus according to claim 9 wherein the means for heating the main processing chamber and for heating the secondary processing chamber are configured to provide a supply of hot gas to the secondary processing chamber having a higher oxygen content than the hot gas provided to the primary processing chamber.

1 1 An apparatus according to any one of the preceding claims further comprising a means of dividing the secondary processing chamber into a first part having the eddy current separator associated therewith and a second part.

12 An apparatus according to claim 11 when dependant on claim 9 wherein the hot gas is provided to the second part of the secondary processing chamber.

13 A method of pyrolysing or gasifying material containing an organic content and non-ferrous metal, comprising

heating, in the main processing chamber of a rotating oven .material containing an organic content to a first temperature in a low or zero oxygen environment to process it to release syngas;

transferring said processed material from said main processing chamber to a secondary processing chamber of the oven; and

separating the non-ferrous metal from the remainder of the processed material using the eddy current separator. 14 A method according to claim 13, the method further comprising:

after completion of the processing of the material in the first processing chamber selectively opening a gate between said main processing chamber and said secondary processing chamber; and

moving said oven to cause the processed material to pass from the main processing chamber to the secondary processing chamber.

15 A method according to claim 13 or claim 14, the method further comprising: providing a separation chamber; and

operating the eddy current separator to move the non-ferrous metals into the separation chamber.

16 A method according any one of claims 13 to 15 further comprising

providing an electromagnet on said oven; and

rotating said oven such that the material within the oven passes said electromagnet as the oven rotates such that said ferrous material is separated therefrom.

17 A method according to claim 16 wherein the ferrous material is separated after the material in the main processing chamber has been processed.

18 A method according to any one of claims 13 to 17 further comprising:

heating the material in the secondary processing chamber.

19 A method according to claim 18 comprising heating the material in the secondary processing chamber to second temperature higher than the first temperature.

20 A method according to claim 18 or 19 comprising:

providing a flow of hot gas to the main processing chamber to heat the material therein in a first stage of processing; and

providing a flow of hot gas to the secondary processing chamber to heat the material therein in a second stage of processing. 21 A method according to claim 20 wherein providing a supply of hot gas to the secondary processing chamber in the second mode of operation comprises providing a flow of hot gas to the secondary processing chamber having a higher oxygen content than the flow of hot gas provided to the primary processing chamber.

22 A method according to any one of claims 13 to 21 wherein the step of separating the non-ferrous metals from the processed material precedes the step of heating the material in the secondary processing chamber.

23 A method according to claim 22 further comprising, after separating the non- ferrous metals from the material within the second chamber:

dividing the second chamber into a first part having the eddy current separator associated therewith and a second part containing the material; and

heating the material in the second part of the secondary processing chamber.