NZ569678A - Continuous pyrolysis processing unit having screw auger heat exchanger pyrolyser - Google Patents

Abstract

A method of producing syngas from an organic raw material which has a moisture content of between 40% and 80% is disclosed, wherein the process includes the steps of: (a) conveying an organic raw material in the absence of oxygen multiple times through a heat exchanger which provides sufficient heat and increased residence time such that the raw material undergoes continuous slow pyrolysis conversion; and (b) separating the resulting syngas, tar, oil and water mixture from the char residue. Also disclosed is a continuous process unit (as shown in figure 2) used to pyrolyse an organic raw material which has a moisture content of between 40% and 80% wherein the unit includes: (a) an auger that conveys an organic raw material in the absence of oxygen multiple times through a heat exchanger providing sufficient heat and increased residence time such that the organic raw material undergoes slow pyrolysis conversion; and (b) at least one subsequent separation unit operation to produce a syngas, tar, oil and water mixture along with a separate char mixture. Preferably, the heat exchanger is a spiral heat exchanger that wraps around the screw auger which transports the organic raw material in a direct line through a screw.

Description

CONTINUOUS PYROLYSIS PROCESSING UNIT STATEMENT OF CORRESPONDING APPLICATIONS This application is based on the Provisional specification filed in relation to New 5 Zealand Patent Application Number 569678, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD The invention relates to a continuous pyrolysis processing unit. More specifically, 10 the invention relates to a processing unit that converts via pyrolysis, a granulated organic material such as sawdust on a continuous basis to syngas and other byproducts.

BACKGROUND ART Pyrolysis relates to the chemical decomposition of organic materials by heating in the absence of oxygen or any other reagents except steam. The chemistry of the process involves converting the organic material into a mixture of solid char and gaseous syngas (typically a mix of hydrogen and carbon monoxide) along with tars, A basic aim of the process is to recover value from waste streams.

At present there are various pyrolysis operations in existence, typically only on a small scale though as pyrolysis struggles to compete commercially against simple incineration (combustion) in dealing with the waste materials. Until recent changes 1 such as becoming carbon neutral, there has been little demand for processes that further utilise waste streams as the economics have been found wanting.

With recent changes in consumer demand and increasing Governmental regulations, the move to processing waste streams in more 'green' ways is 5 increasing and pyrolysis offers some promise in this area. For example, pyrolysis can be used in conjunction with gas turbines to create better overall process efficiency than by conventional fossil-fuel energy generation. By not using or reducing use of fossil fuels, waste pyrolysis can help to meet renewable energy targets. Another advantage of pyrolysis processing is that it can be scaled up or 10 down easily for a range of different operations.

Existing processes utilising pyrolysis have a number of drawbacks for example: (a) They are generally batch or semi-batch processes where raw material is added to a unit, processed and removed before addition of further material; (b) Char produced in pyrolysis needs to be removed from the unit prior to 15 further processing making the process even more batch dependent; (c) The energy requirements are very significant and few processes recycle heat produced or recycle heat and still produce useful amounts of excess energy; (d) The energy produced is insufficient to be commercially viable for 20 applications such as power generation.

A yet further difficulty of pyrolysis is that this process is slightly endothermic.

To address the above drawbacks various methods have been proposed to provide heat to the reacting biomass particles including: 2 • Partial combustion of the biomass products through air injection. This results in poor quality products; • Direct heat transfer with a hot gas, ideally a product gas that is reheated and recycled. The problem is to provide enough heat with reasonable gas flows; • Indirect heat transfer with exchange surfaces (wall, tubes). It is difficult to achieve good heat transfer on both sides of the heat exchange surface; • Direct heat transfer with circulating solids. Solids transfer heat between a burner and a pyrolysis reactor. This is an effective but complex technology.

Some prior art methods used for biomass pyrolysis include: • Fixed beds e.g. for production of charcoal. Problems with this method include poor, slow heat transfer resulting in low yields; • Augers mixing a heated inert substance such as sand with biomass particles. This provides good residence time but mechanical reliability is a concern and as a consequence there are no commercial size augers in operation using a mix of sand and biomass; • Ablative processes where the biomass particles are moved at high speed against a hot metal surface. This process has the problem of mechanical reliability and requires mixing with another carrier gas; • Fluidised beds are also proposed although again have inherent mechanical problems and requires the use of another gas to fluidise the biomass particles.

It is known that pyrolysis can be completed to produce syngas in sufficient quantities to power both the energy needed for pyrolysis and some excess production. The degree of excess production is important though to ensure that any process using this reaction is commercially viable.

It should therefore be appreciated by those skilled in the art that it would be an advantage to have a processing unit that utilised the benefits of pyrolysis including gas production and low residue and that also is: 1. Continuous in operation; 2. Utilises a waste stream in a manner that helps to reduce overall process energy requirements; 3. Recycles energy to maximise energy gained; 4. Does not require mixing of other fluids with the raw material; . Ideally produces additional by-products that may add value to the primary process; 6. Minimises the number of moving mechanical parts and therefore maximises mechanical reliability; and, 7. Produces syngas with sufficient calorific value and volume to be commercially viable.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a 4 number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be 5 attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 10 'comprising' is used in relation to one or more steps in a method or process.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a process unit used to pyrolyse an organic raw material wherein the unit includes: (a) an auger that conveys an organic raw material through a heat exchanger providing heat sufficient that the organic raw material undergoes pyrolysis; and, (b) at least one subsequent separation step to produce a syngas, tar, oil and water mixture along with a separate char mixture.

Preferably, the organic raw material used has a moisture content of between 40% and 100%.

Preferably, pyrolysis of the organic raw material as described above is done in the complete absence of oxygen. To assist in achieving these conditions the auger is sealed from the environment.

In preferred embodiments, the organic raw material is a waste stream from other 5 processing such as forestry processing. In an alternative embodiment, the organic raw material is a biomaterial such as lucerne. In one preferred embodiment the raw material may be saw dust although it should be appreciated that other raw materials may be used such as coal. As may be appreciated saw dust is a useful raw material as it is a waste stream from forestry related processing and generally 10 not processed further or processed in a way that does not add value e.g. combustion. A further issue with combustion is that, with increasing focus on reducing carbon release, combustion as a waste measure is becoming less acceptable.

Preferably, the raw material is granulated. In a preferred embodiment the granule 15 size is less than approximately 10mm2. More preferably, the granules range in size from 0.5mm2 to 5mm2.

As noted above, it is preferable that the raw material have a high (greater than 40%) to very high moisture content. This may be achieved by soaking the organic raw material in water before processing. The inventors have found that use of wet 20 organic material is important in producing sufficient syngas useful for preferred applications such as running a gas turbine to generate energy. Comparison experiments with prior art raw materials using the invention process unit have resulted in good energy conversion (calorific value) using the invention apparatus (2 to 3 times greater than the art) but the volume of gas produced is significantly 25 greater for moist raw material. This increased volume of gas produced has a significant impact on the commercial strength of the process unit. 6 Preferably, the auger transports the organic raw material through a heat exchanger and pyrolysis of the raw material occurs inside the auger. In one embodiment, the auger transports the raw material in a direct line through a single screw and in one pass. In an alternative embodiment, the auger may include multiple screws and 5 optionally may pass multiple times through the exchanger therefore increasing the residence time in the heated environment thereby encouraging further pyrolysis conversion.

Preferably, the heat exchanger is a spiral heat exchanger that wraps around the auger. This type of exchanger lends itself well to this application due to the high 10 number of heat transfer surfaces although other exchangers may be used without departing from the scope of the invention.

Preferably, the organic raw material reaches a temperature of approximately 900°C whilst being transported through the heat exchanger. Other temperatures are envisaged particularly if the raw material were to be pressurised. For the purposes 15 of clarity it is noted that, in this preferred embodiment, the raw material is not pressurised although this option is not ruled out.

Preferably, the heat exchanger heat source is a fluid with an inlet temperature of approximately 1000°C. It should be appreciated that other temperatures may be used depending on the heat exchanger design or raw material however, in the 20 preferred embodiment of a spiral heat exchanger, this inlet temperature is desirable.

In one embodiment, the heat source may be exhaust gases from a combustion chamber using a fuel such as gas, coal, oil, saw dust and so on.

In the above embodiment, the fuel may be mixed with char produced from step (b) 25 of the process. In this embodiment, the aim is to reduce the amount of solid residue produced from the process unit. What may be appreciated by those skilled in the art is that the char is itself a useful by-product and may instead be used in further processing such as in the manufacture of carbon filters.

Preferably, the separation process in step (b) occurs in a sealed vessel (char separator) and char settles as a solid to the bottom of the vessel while the syngas, 5 water vapour, tar and oil all exit from the top of the vessel as a mixed gas.

Preferably, the char in the char separator is removed using an auger. In one embodiment, the char inside the char separator is fluidised. A preferred method of fluidising the char is to inject steam into the settled char. As may be appreciated, this step helps to avoid the char bridging and encourages flow of the char into the 10 auger and out of the separator.

The inventors have found that the char produced is a stable and finely granulated material. The above findings show that the char may be useful for applications such as in carbon filters therefore giving the process a significant advantage in that it takes a waste stream (saw dust) and adds a high amount of value in producing 15 more valuable by products.

Preferably, the water vapour, syngas, oil and tar mixture is further processed by step (c): (c) the water vapour, syngas, oil and tar mixture is passed through a condenser to separate out water vapour from the syngas, oil and tar.

In one embodiment, the amount of water removed constitutes approximately 40-50% of the weight of the organic raw material used e.g. for a 3kg feed amount of saw dust, approximately 1.4 to 1.5kg of water is collected from the condenser.

Preferably, the syngas, oil and tar mixture is further processed by step (d): 3 (d) the syngas, oil and tar mixture is passed through a separator containing water to separate syngas from the tar and oil mixture.

In one embodiment, the separator is a sealed tank filled with water. The mixture of syngas, tar and oil is fed into the tank water and through gravity the tar and oil fall 5 to the base of the tank while the syngas rises to the tank surface and is collected.

In one embodiment, the amount of tar and oil collected constitutes less than 1% of the initial organic raw material feed by volume e.g. for a 3kg feed amount of saw dust, less than 1 ml of tar and oil is collected. In one trial completed by the inventors the amount of tar and oil collected was approximately 65ml.

The inventors have found that the tar and oil mixture produced is a viscous liquid that has a low flash point. The above observations show that the mixture may be useful as an alternative to traditional fossil fuels such as petrochemical oils.

Another option is to use this by-product for traditional uses of wood tars and oils such as in cosmetics and other personal care formulations.

In one embodiment, the amount of syngas collected constitutes approximately 40% by weight of the initial organic raw material feed e.g. for a wet 3kg feed amount of saw dust, approximately 1.25kg of syngas is collected.

The inventors have found that the syngas produced in the invention has a marked difference to that produced from dryer raw materials used in the prior art. By way 20 of example, the inventors completed a side by side trial comparing the burning properties of syngas produced according using the invention process unit compared to the burning properties of syngas produced using the same process unit but with a raw material containing 12-14% moisture content (as is more common in the art). The invention syngas ignited far more easily and burnt for 1 25 hour and 5 minutes as compared to 20 minutes for the dry (12-14%) raw material. 9 The results were very surprising and suggested either an increased volume in syngas produced and/or a syngas with a higher energy value.

Chemical analysis of the invention syngas confirms that the syngas contains 10 to 30% methane, 10 to 30% hydrogen and 20 to 40% carbon monoxide. The overall 5 calorific value for the syngas produced by the process is approximately 400 BTU/ft3. As may be appreciated by those skilled in the art, this calorific value is considerably higher than art pyrolysis methods (150-200 BTU/ft3). The value is also three times higher than would be obtained from prior art gasification methods.

The value is also at a level sufficient to be more commercially viable. For example 10 a commercial size gas turbine ideally requires a calorific content of at least 350 BTU/ft3 which prior art gases struggle to achieve if achieved at all.

Preferably, the syngas produced from step (d) is further processed by step (e): (e) the syngas is passed through a gas turbine which is used to generate energy.

In an alternative embodiment, the syngas is used for further processing such as in the production of petrochemicals including methanol.

According to another aspect of the present invention there is provided a method of producing syngas from an organic raw material by the steps of: (a) conveying an organic raw material in the absence of oxygen through a heat 20 exchanger which provides sufficient heat that the raw material undergoes pyrolysis; and, (b) separating the resulting syngas, tar, oil and water mixture from the char residue.

According to another aspect of the present invention there is provided a method of producing syngas from an organic raw material using the process unit substantially as described above.

Preferably, the organic raw material has a moisture content of between 40% and 5 100%.

Preferably, the water vapour, syngas, oil and tar mixture is further processed by step (c): (c) the water vapour, syngas, oil and tar mixture is passed through a condenser to separate out water vapour from the syngas, oil and tar.

Preferably, the syngas, oil and tar mixture is further processed by step (d): (d) the syngas, oil and tar mixture is passed through a separator containing water to separate out syngas from the tar and oil mixture.

Preferably, the syngas produced from step (d) is further processed by step (e): (e) the syngas is passed through a gas turbine which is used to generate energy.

According to another aspect of the present invention there is provided syngas produced from a pyrolysis process containing 10 to 30% methane, 10 to 30% hydrogen and 20 to 40% carbon monoxide. Preferably, the overall calorific value of the syngas produced is approximately 400 BTU/ft3.

According to another aspect of the present invention there is provided syngas produced by the method or from the process unit substantially as described above.

According to another aspect of the present invention there is provided char residue produced by the method or from the process unit substantially as described above. 11 According to another aspect of the present invention there is provided a tar and oil mixture produced by the method or from the process unit substantially as described above.

It should be appreciated from the above description that there is described a processing unit and method for producing syngas from a waste stream via pyrolysis. The advantages which should be apparent to those skilled in the art include the fact that the process unit and method: • Operate on a continuous basis; • Utilise waste streams such as saw dust in a manner that helps to reduce overall process energy requirements; • Recycle energy and materials produced to maximise energy gained; • Does not require mixing of other fluids with the raw material; • Produces the by-products of syngas and tar that can be used to generate energy and/or be used as materials in other processes; • Minimises the number of moving mechanical parts and therefore maximises mechanical reliability; and, • Produces a syngas with sufficient calorific value and volume as to be commercially viable.

BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: 12 Figure 1 shows a process flow diagram showing one embodiment of the present invention; and, Figure 2 shows a process flow diagram showing an alternative embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION The invention is now described with reference to a preferred process unit.

EXAMPLE 1 Referring to Figure 1, a process flow diagram is shown generally by arrow 10 of one embodiment of the present invention.

Raw material 11 is stored in a hopper 12. In the example shown, the raw material 10 is saw dust with a particle size of between approximately 0.5mm2 to 5mm2 and 15 with all material 11 less than 10mm2. The raw material 11 is saturated in water (not shown) to give the raw material a moisture content of at least 40% to 100%. The outlet of the hopper 12 is connected to a screw auger 13 which transports the raw material 11 through a heat exchanger 14. In the example a spiral heat exchanger 14 is used to achieve the preferred amount of heat transfer surface. 20 The raw material 11 is heated indirectly in the exchanger 14 (no mixing of raw material 11 with other fluids) by a heat source stream 15. In the example, the raw material 11 temperature reaches 900°C by at least the outlet 16 inducing pyrolysis of the raw material 11. The pyrolysed material is separated in the char separator 17 with the water vapour, syngas, tar and oils 18 being collected from the top of the 13 vessel 17 and the char residue 19 falling by gravity to the bottom of the char separator 17.

The water vapour, syngas, tar and oils mixture 18 is then passed through a condenser 20 and any water vapour 21 removed.

The remaining syngas, tar and oil mixture 22 is then bubbled into water in a tank 23 and the tars and oil settle on the tank bottom 24 via gravity while the syngas 25 is collected from the top of the tank 23. Syngas collected 25 may then be used to generate energy for example via a gas turbine 26 and generator 27 or may be used as a raw material for other processes.

EXAMPLE 2 In this example, production from a small scale plant following the process of Example 1 is described.

Approximately 3kg of saw dust 11 with a particle size of between 0.5mm2 and 5mm2 was processed. The saw dust 11 was 100% water saturated.

After processing a mass balance was completed and the unit was found to produce: 1.45kg of water 21 1.25kg of syngas 25 230g of char residue 19 65ml of an oil and tar mixture 24 The composition of the syngas 25 was analysed and found to contain: 14 Component / Property Amount ch4 19.8% co2 23.8 % C2H- 1.4% c2h6 1.9% c3h6 0.9 % c3h8 0.4 % h2 .0 % 02 0.9 % n2 2.5 % CO 33.6 % Higher Heating Value .94 MJ/dry standard cubic metre Lower Heating Value .22 MJ/dry standard cubic metre Based on the above, the resulting syngas 25 shows promise for energy production or in the manufacture of other products e.g. methanol production. This is because it contains a greatly elevated level of at least hydrogen and carbon monoxide than 5 usual for syngas. In addition the calorific values are higher than that normally expected for pyrolysis manufactured syngas.

The char residue 19 is a very stable and finely granulated material that based on its composition shows promise for use in carbon filters.

The tar and oil mixture 24 also shows promise as a by product of the process. 10 Ignition tests showed that the tar and oil mixture has a very low flash point so may have applications as an alternative fuel or replacement for existing petrochemical oils or in personal care formulations such as in cosmetics EXAMPLE 3 A further test of the process described in Examples 1 and 2 was completed to determine the quality of the syngas 25.

The syngas 25 collected from the trial described in Example 2 was ignited and the flame height and burn time noted.

A second trial was completed using the same conditions as described in Examples 1 and 2 except that the raw material 11 moisture content was reduced to a level more typically used in the art, in this case 12-14%. The syngas collected was also ignited using the same apparatus as the Example 2 syngas and the flame height 5 the burn time noted.

The comparison found that both flames had a height of approximately 300mm but there were marked differences in the burn time. The high moisture content Example 2 sawdust used in the invention burnt for approximately 1 hour and 5 minutes. By comparison the 12-14% moisture content sawdust only burnt for 10 approximately 20 minutes.

A chemical analysis of the syngas produced from the 12-14% moisture content sawdust revealed that, the invention syngas contains more methane and carbon monoxide and less carbon dioxide.

The above results showed that the initial moisture content of the saw dust clearly 15 has a very significant impact on the syngas composition and/or syngas volume produced and shows a marked difference to the art. One reason proposed for the difference may be that, during the drying process, tannins and other volatile compounds in the material may be driven off which in fact add to the calorific value of the resulting syngas.

EXAMPLE 4 Referring to Figure 2, a further example is now described showing options that may be used to recycle energy in the process unit shown generally by arrow 101. 16 Figure 2 shows a similar process diagram 25 Example 1 but with a combustor 101 used to provide a heat source 102 to the heat exchanger 103 used in pyrolysing the saw dust raw material 104.

The material 105 burnt in the combustor 101 is a mix of the char residue106 from 5 the char separator107 along with another burnable material 108 such as fossil fuels, saw dust and so on. An aim of combusting the char residue 106 is to minimise the production of solid waste from the process 100. By feeding the char 106 into the combustor 101, there is either no solid waste or minimal amounts left over from the process 100, although as noted above in Example 2, the char 102 10 may not be used as a heat source 102 and instead used as a by-product stream (not shown).

Another recycle option not shown is to take the low grade heat from the heat exchanger outlet 108 and use this to pre-heat the burnable material 108 before entry into the combustor 101 shown at point A. This recycle step is only likely to be 15 warranted where the temperature of the fluid at the heat exchanger 103 outlet 108 is sufficiently high to balance the cost of installing a recycle line and secondary heat exchanger (not shown).

The above examples describe examples of the processing unit and methods for producing syngas from a waste stream via pyrolysis. Selected advantages of the 20 invention process include continuous processing, and better energy management.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims. 17

Claims (37)

WHAT WE CLAIM IS:

1. A method of producing syngas from an organic raw material which has a moisture content of between 40% and 80% including the steps of: (a) conveying an organic raw material in the absence of oxygen multiple times through a heat exchanger which provides sufficient heat and increased residence time such that the raw material undergoes continuous slow pyrolysis conversion; and, (b) separating the resulting syngas, tar, oil and water mixture from the char residue.

2. The method as claimed in claim 1 wherein the raw material used in step (a) has been soaked in water before processing.

3. The method as claimed in claim 1 or claim 2 wherein the raw material is granulated.

4. The method as claimed in any one of the above claims wherein the raw material is saw dust

5. The method as claimed in any one of the above claims wherein pyrolysis of the organic raw material completed in step (a) occurs in the complete absence of oxygen.

6. The method as claimed in any one of the above claims wherein conveying in step (a) is completed using an auger that transports the raw material through a heat exchanger and pyrolysis of the raw material occurs inside the auger. 18

7. The method as claimed in any one of the above claims wherein the raw material reaches a temperature of approximately 900°C in step (a).

8. The method as claimed in any one of the above claims wherein the heat exchanger is a spiral heat exchanger with a heat source is a fluid with an inlet temperature of approximately 1000°C.

9. The method as claimed in claim 8 wherein the heat source is an exhaust gas from a combustion chamber fuelled by a combustible material.

10. The method as claimed in claim 9 wherein the combustible material may be mixed with char produced from step (b) of the process.

11. The method as claimed in any one of the above claims wherein step (b) occurs in a sealed vessel and char settles as a solid to the bottom of the vessel while the syngas, water vapour, tar and oil all exit from the top of the vessel as a mixed gas.

12. The method as claimed in claim 11 wherein the char in the char separator is removed using an auger.

13. The method as claimed in claim 11 or claim 12 wherein the char inside the char separator is fluidised.

14. The method as claimed in claim 13 wherein the char is fluidised by injecting steam into the char.

15. The method as claimed in any one of the above claims wherein the water vapour, syngas, oil and tar mixture is further processed by step (c): (c) the water vapour, syngas, oil and tar mixture is passed through a condenser to separate out water vapour from the syngas, oil and tar. 19

16. The method as claimed in claim 15 wherein the syngas, oil and tar mixture is further processed after step (c) by step (d): (d) the syngas, oil and tar mixture is passed through a separator containing water to separate syngas from the tar and oil mixture.

17. The method as claimed in claim 16 wherein the separator is a sealed tank filled with water.

18. The method as claimed in claim 16 or claim 17 wherein the mixture of syngas, tar and oil is fed into the tank water and through gravity the tar and oil fall to the base of the tank while the syngas rises to the tank surface and is collected.

19. The method as claimed in any one of the above claims wherein the tar and oil mixture produced is a viscous liquid that has a low flash point.

20. The method as claimed in any one of the above claims wherein the amount of syngas collected constitutes approximately 40% by weight of the initial organic raw material feed.

21. The method as claimed in any one of the above claims wherein the syngas produced by the method contains 10 to 30% by weight methane, 10 to 30% by weight hydrogen and 20 to 40% by weight carbon monoxide.

22. The method as claimed in any one of the above claims wherein the syngas produced by the method has an overall calorific value of approximately 400 BTU/ft3

23. A syngas produced by the method as claimed in any one of claims 1 to 22.

24. A char produced by the method as claimed in any one of claims 1 to 22. 20

25. A tar and oil mixture produced by the method as claimed in any one of claims 1 to 22.

26. A continuous process unit used to pyrolyse an organic raw material which has a moisture content of between 40% and 80% wherein the unit includes: (a) an auger that conveys an organic raw material in the absence of oxygen multiple times through a heat exchanger providing sufficient heat and increased residence time such that the organic raw material undergoes slow pyrolysis conversion; and, (b) at least one subsequent separation unit operation to produce a syngas, tar, oil and water mixture along with a separate char mixture.

27. The process unit as claimed in claim 26 wherein the separation unit operation is a condenser used to separate out water vapour from the syngas, oil and tar.

28. The process unit as claimed in claim 27 wherein, after condensation, the syngas, oil and tar mixture is further processed in a tank separator containing water to separate out syngas from the tar and oil mixture.

29. The process unit as claimed in any one of claims 26 to 28 wherein the overall calorific value of the syngas produced is approximately 400 BTU/ft3.

30. A method of producing syngas from an organic raw material substantially as hereinbefore described in Examples 1 to 3 and Figure 1.

31. A method of producing syngas from an organic raw material substantially as hereinbefore described in Example 4 and Figure 2.

32. A syngas produced from an organic raw material substantially as hereinbefore described in Examples 1 to 3 and Figure 1. 21

33. A syngas produced from an organic raw material substantially as hereinbefore described in Example 4 and Figure 2.

34. A char produced from an organic raw material substantially as hereinbefore described in Examples 1 to 3 and Figure 1.

35. A char produced from an organic raw material substantially as hereinbefore described in Example 4 and Figure 2.

36. A tar and oil mixture produced from an organic raw material substantially as hereinbefore described in Examples 1 to 3 and Figure 1.

37. A tar and oil produced from an organic raw material substantially as hereinbefore described in Example 4 and Figure 2. Lakeland Steel Products Limited by their Attorneys James & Wells Intellectual Property 22