A METHOD FOR THE PRODUCTION OF DIESEL

Abstract

A method for preparing feed material for a catalytic depolymerisation process, the method comprising the steps of: separating feedstock into two or more feedstock streams based on one or more properties of the feedstock, introducing each of the two or more feedstock streams into one or more process vessels, processing the feedstock streams in the presence of a catalyst in the process vessels under conditions of elevated temperature in order to produce two or more intermediate feedstock streams, and blending the two or more intermediate feedstock streams to form the feed material.

Claims

1. A method for preparing feed material for a catalytic depolymerisation process, the method comprising the steps of: separating feedstock into two or more feedstock streams based on one or more properties of the feedstock, introducing each of the two or more feedstock streams into one or more process vessels, processing the feedstock streams in the presence of a catalyst in the process vessels under conditions of elevated temperature in order to produce two or more intermediate feedstock streams, and blending the two or more intermediate feedstock streams to form the feed material.

2. A method according to claim 1 wherein the one or more properties of the feedstock include the type of material in the feedstock.

3. A method according to claim 1 wherein the feedstock streams include a biomass feedstock stream and a polymeric material feedstock stream.

4. A method according to claim 1 wherein each of the feedstock streams is subject to a size reduction process prior to being introduced to the one or more process vessels.

5. A method according to claim 4 wherein particles exiting the size reduction process are separated on the basis of particle size, with particles below a predetermined particle size being introduced to the one or more process vessels.

6. A method according to claim 5 wherein the particles introduced to the process vessels have a particle size of between about 20 mm and about 1000 mm.

7. A method according to claim 1 wherein the elevated temperature in the process vessels is between about 160° C. and about 200° C.

8. A method according to claim 1 wherein the feedstock streams are introduced to the process vessels in the presence of a medium heated to the elevated temperature.

9. A method according to claim 8 wherein the medium is a carrier oil in the form of a mineral oil, a vegetable oil or a petroleum oil.

10. A method according to claim 1 wherein the catalytic depolymerisation process is conducted in the presence of a catalyst, the catalyst comprising a liquid catalyst.

11. A method according to claim 10 wherein the liquid catalyst comprises an ionic liquid catalyst.

12. A method according to claim 11 wherein the ionic liquid catalyst comprises methylimidazolium and/or pyridinium ions.

13. A method according to claim 1 wherein the pH in the process vessels is maintained in the range of between 8 and 12.

14. A method according to claim 1 wherein the one or more process vessels are agitated using one or more recirculating pumps.

15. A method according to claim 1 wherein each of the two or more intermediate feedstock streams are substantially homogenous.

16. A method according to claim 1 wherein each of the two or more intermediate feedstock streams comprise between about 25% and 35% solids.

17. A method according to claim 16 wherein the solids in the intermediate feedstock streams are no larger than about 2.5 mm.

18. A method according to claim 3 wherein the biomass feedstock stream forms a biomass intermediate feedstock stream and the polymeric feedstock stream forms a polymeric intermediate feedstock stream.

19. A method according to claim 18 wherein the intermediate feedstock streams are blended in a ratio of the polymeric intermediate feedstock stream to the biomass intermediate feedstock stream of between about 75:25 to 35:65.

20. A method for preparing feed material for a catalytic depolymerisation process, the method comprising the steps of: introducing a feedstock stream into a process vessel, processing the feedstock stream in the presence of a medium in the process vessel consisting of an ionic liquid or mixture of ionic liquid in order to produce the feed material.

21. A method according to claim 20 wherein the ionic liquid or mixture of ionic liquids comprises methylimidazolium and/or pyridinium ions.

22. A method according to claim 20 wherein the ionic liquid is 1-Butyl-3-methylimidazolium chloride.

23. A method according to claim 20 wherein the process vessel is operated at an elevated temperature.

24. A method according to claim 23 wherein the elevated temperature is between about 100° C. and about 140° C.

25. A method for the production of diesel comprising the steps of: introducing a feed material into a reaction vessel, the reaction vessel being associated with one or more agitation devices adapted to agitate the feed material so as to ensure the substantial homogeneity of the feed material, treating the feed material in the reaction vessel under conditions of elevated temperature in order to vaporise at least a portion of the feed material to form a vaporised feed material, introducing the vaporised feed material to a fractionating column to form a diesel fraction, removing the diesel fraction from the fractionating column and condensing the diesel fraction to form diesel, and wherein the method is operated on a continuous basis.

26. A method according to claim 25 wherein a reaction occurring in the reaction vessel is a catalytic depolymerisation process.

27. A method according to claim 26 wherein the catalytic depolymerisation process is conducted in the presence of a catalyst, the catalyst comprising a liquid catalyst.

28. A method according to claim 27 wherein the liquid catalyst comprises an ionic liquid catalyst.

29. A method according to claim 28 wherein the ionic liquid catalyst comprises methylimidazolium and/or pyridinium ions.

30. A method according to claim 25 wherein the elevated temperature in the reaction vessel is between about 160° C. and about 220° C.

31. A method according to claim 25 wherein the reaction vessel is adapted to substantially preclude oxygen from entering the reaction vessel.

32. A method according to claim 25 wherein the one or more agitation devices comprise one or more recirculating pumps.

33. A method according to claim 25 wherein the diesel has a sulphur content of no more than 15 ppm.

34. A method for the removal of sulphur and/or nitrogen from diesel, the method comprising the steps of introducing diesel containing sulphur and/or nitrogen into a vessel containing one or more ionic liquids, and contacting the one or more ionic liquids and the diesel such that at least a portion of the sulphur and/or nitrogen in the diesel is separated therefrom.

35. A method according to claim 34 wherein the at least a portion of the sulphur is removed from the diesel in the form of gaseous sulphur dioxide.

36. A method according to claim 34 wherein, following sufficient contact between the one or more ionic liquids and the diesel, the ionic liquid and the diesel are heated to an elevated temperature to selectively evaporate the diesel from the ionic liquid.

37. A method according to claim 36 wherein the elevated temperature is approximately 200° C.

38. A method according to claim 34 wherein the ionic liquid comprises methylimidazolium and/or pyridinium ions.

39. A method for the production of diesel, the method comprising: forming a feed material according to the method of claim 1; and forming diesel from the feed material, the method for forming diesel from the feed material comprising: introducing a feed material into a reaction vessel, the reaction vessel being associated with one or more agitation devices adapted to agitate the feed material so as to ensure the substantial homogeneity of the feed material, treating the feed material in the reaction vessel under conditions of elevated temperature in order to vaporise at least a portion of the feed material to form a vaporised feed material, introducing the vaporised feed material to a fractionating column to form a diesel fraction, removing the diesel fraction from the fractionating column and condensing the diesel fraction to form diesel, and wherein the method is operated on a continuous basis.

40. A method for the production of diesel, the method comprising forming a feed material according to the method of claim 20; the method for forming the feed material comprising: and forming diesel from the feed material according to the method, the method of forming the diesel from the feed material comprising: introducing a feed material into a reaction vessel, the reaction vessel being associated with one or more agitation devices adapted to agitate the feed material so as to ensure the substantial homogeneity of the feed material, treating the feed material in the reaction vessel under conditions of elevated temperature in order to vaporise at least a portion of the feed material to form a vaporised feed material, introducing the vaporised feed material to a fractionating column to form a diesel fraction, removing the diesel fraction from the fractionating column and condensing the diesel fraction to form diesel, and wherein the method is operated on a continuous basis.

41. The method according to claim 39, further comprising removing at least a portion of sulphur in the diesel by: introducing diesel containing sulphur and/or nitrogen into a vessel containing one or more ionic liquids, and contacting the one or more ionic liquids and the diesel such that at least a portion of the sulphur and/or nitrogen in the diesel is separated therefrom.

42. The method according to claim 40, further comprising removing at least a portion of sulphur in the diesel by: introducing diesel containing sulphur and/or nitrogen into a vessel containing one or more ionic liquids, and contacting the one or more ionic liquids and the diesel such that at least a portion of the sulphur and/or nitrogen in the diesel is separated therefrom.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0164] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[0165] FIG. 1 illustrates a flowsheet of a feedstock sorting process according to an embodiment of the present invention.

[0166] FIG. 2 illustrates a flowsheet of a method for the production of diesel according to an embodiment of the present invention.

[0167] FIG. 3 illustrates a cutaway view of a process vessel according to an embodiment of the present invention.

[0168] FIG. 4 illustrates a cross-sectional view of a process vessel according to an embodiment of the present invention.

[0169] FIG. 5 illustrates a device for the addition of catalyst to a process stream according to an embodiment of the present invention.

[0170] FIG. 6 illustrates a flowsheet of a method for the production of diesel according to an alternative embodiment of the present invention.

[0171] FIG. 7 illustrates a flowsheet of a method for the removal of sulphur from diesel according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

[0172] In FIG. 1 a flowsheet of a feedstock sorting process according to an embodiment of the present invention is illustrated. The feedstock sorting process is adapted to prepare two or more feedstock streams for use in the preparation of feed material for a catalytic depolymerisation process.

[0173] In FIG. 1, feedstock in the form of polymeric materials (plastic, tyres, rubber and so on) is stored in a polymeric material storage bunker 10, while feedstock in the form of biomass (timber and other vegetation-based matter) is stored in a biomass storage bunker 11. Material from the storage bunkers 10, 11 is transferred by conveyors 12 (in a ratio of 70% polymeric materials to 30% biomass and at a throughput of 6 tonnes/hour) to a pre-sorting process 13 where waste 14 (for instance, in the form of glass, rock and other non-treatable waste) is removed from the feedstock. The remaining feedstock is subject to a size reduction process in shredders 15 after which the shredded feedstock is screened using a trommel 16 having 5 mm apertures.

[0174] Undersize streams 17 of particles of less than 5 mm that pass through the trommel 16 are transferred to feedstock stream storage silos 18, while oversize streams of particles of over 5 mm are brought into close proximity to magnets 19 in order to removed magnetic impurities (especially ferrous impurities).

[0175] Following the removal of magnetic impurities, the oversize streams are again subject to a size reduction process in shredders 20 to reduce the size of the particles in the oversize streams to below 5 mm. The oversize feedstock streams are then combined with the undersize feedstock streams in the storage silos 18. It is envisaged that the silos 18 may be sized so as to hold sufficient material to allow the processing plant to keep operating for a period of time, even in the event of an interruption to the supply of feedstock. Preferably, the silos 18 hold sufficient material so that the processing plant could continue to operate for at least two weeks should an interruption to the supply of feedstock occur.

[0176] Given that it is desirable to store material in the silos 18 for a period of time, the minimisation of fine material in the feedstock streams is also desirable due to the possibility of self-combustion. Thus, it is preferred that the majority of the particles in the feedstock streams are greater than 5 mm in size. In a particular embodiment, the average particle size in the feedstock streams may be about 50 mm.

[0177] From the storage silos 18, the feedstock streams are transferred via a pneumatic conveyor system 21 to a plurality of process vessels 22.

[0178] In FIG. 2 a flowsheet of a method for the production of diesel according to an embodiment of the present invention is illustrated. Feedstock 23 is split (using the flowsheet of FIG. 1) into a polymeric material feedstock stream 24 and a biomass feedstock stream 25. Each feedstock stream 24, 25 is introduced into a process vessel 26. The process vessels are sealed with airlock gates 27 and are maintained with a nitrogen atmosphere so as to prevent oxygen from entering the process vessels 26. Each process vessel 26 is maintained at a temperature of 180° C. in order to increase the solubility of the solid particles in the feedstock streams 24, 25 in the carrier oil (in this embodiment, biodiesel) in the process vessels 26.

[0179] The process vessels 26 are agitated using impellers 28, although further agitation is provided using inline mixers 29 that extract material from a lower region of the process vessels 26 and return it to an upper region of the process vessels 26. The inline mixers 29 exert high degrees of suction on the feedstock streams 24, 25 such that even fine, light particles floating on the surface of the liquid in the process vessels 26 are drawn through the inline mixers 29. The high shear conditions created by the inline mixers 29 (along with the elevated temperatures in the process vessels 26) serve to further reduce the size of particles in the feedstock streams 24, 25 and also to form substantially homogenous intermediate feedstock streams 30 that exit the process vessels 26.

[0180] Catalyst 31 in the form of fine, solid faujasite is added to the process vessels 26, while lime 32 is also added in order to raise the pH of the intermediate feedstock streams 30 to between about 8 and 12.

[0181] Once sufficient solubilisation of the feedstock streams 24, 25 has occurred so that the intermediate feedstock streams 30 have been formed in the process vessels 26, the intermediate feedstock streams 30 may be introduced to a mixing vessel 33 where the intermediate feedstock streams 30 are combined to form the feed material 34.

[0182] As with the process vessels 26, the mixing vessel 33 is sealed with an airlock gate 35 and is maintained with a nitrogen atmosphere so as to prevent oxygen from entering the mixing vessel 33. The mixing vessel 33 is maintained at a temperature of 180° C. in order to increase the solubility of the solid particles in the intermediate feedstock streams 30 in the carrier oil (in this embodiment, biodiesel) in the mixing vessel 33.

[0183] The mixing vessel 33 is agitated using an impeller 36, although further agitation is provided using an inline mixer 37 that extracts material from a lower region of the mixing vessel 33 and returns it to an upper region of the mixing vessel 33. The inline mixer 37 exerts high degrees of suction on the intermediate feedstock streams 30 such that even fine, light particles floating on the surface of the liquid in the mixing vessel 33 are drawn through the inline mixer 37. The high shear conditions created by the inline mixer 37 (along with the elevated temperatures in the mixing vessel 33) serve to further reduce the size of particles in the intermediate feedstock streams 30 and also to form a substantially homogenous feed material 34 that exits the mixing vessel 33. In addition, the high shear conditions enhance even dispersal of the catalyst and lime in the intermediate feedstock streams, thereby increasing the speed of the reaction.

[0184] Catalyst 31 in the form of fine, solid faujasite is added to the mixing vessel 33, while lime 32 is also added in order to maintain the pH of the feed material 34 at between about 8 and 12.

[0185] Once a substantially homogenous feed material 34 is formed in the mixing vessel 33, the feed material 34 is introduced to a reaction vessel 38. The reaction vessel 38 is maintained with a nitrogen atmosphere so as to prevent oxygen from entering the reaction vessel 38. The reaction vessel 38 is maintained at a temperature of 280° C. in order to both assist in the catalytic depolymerisation reaction occurring in the reaction vessel 38 and to vaporise at least a portion of the feed material 34 (preferably at least the diesel fraction of the feed material 34), with the vaporised portion of the feed material 34 entering a fractionating column 39 for recovery of the diesel fraction. Water is also recovered in the fractionating column 39.

[0186] The recovered diesel and water is condensed using a cooler 40, and then the diesel may be separated from the water using a separator 41. The recovered diesel may then either be used or may be treated to upgrade the quality of the diesel.

[0187] The temperature in the reaction vessel 38 is maintained by providing a hot oil tank 42 that circulates hot oil through pipes 43 in the reaction vessel 38. In this way, the temperature of the feed material 34 in the reaction vessel 38 may be maintained at a substantially constant temperature, thereby ensuring a consistent reaction rate within the reaction vessel 38.

[0188] The reaction vessel 38 is associated with a high shear mixer 44 that extracts feed material 34 from a lower region of the reaction vessel 38 and returns it to an upper region of the reaction vessel 38. The high shear mixer 44 assists in ensuring that the feed material 34 remains a substantially homogenous mixture and that the catalyst 31 in the feed material 34 is substantially evenly distributed throughout the feed material 34, in order to ensure high reaction efficiency.

[0189] Periodically, feed material 34 circulating through the high shear mixer 44 may be diverted to a sludge separation process. This diverted feed material 45 is subjected to a separation step (using a decanter) in which sludge from the reaction vessel 38 is separated from diesel.

[0190] Diesel separated from the sludge is returned to the reaction vessel 38, while the sludge is filtered using a belt press (not shown). Diesel recovered from the belt press is also returned to the reaction vessel 38.

[0191] FIG. 3 illustrates a cutaway view of a process vessel 26 according to an embodiment of the present invention. In this embodiment of the invention, the process vessel 26 is agitated using an inline mixer 29 that extracts the feedstock stream in the process vessel 26 from a lower region of the process vessel 26 through pipe 46 and returns it through pipe 47 to an upper region of the process vessel 26.

[0192] It will be seen in FIG. 3 that the high suction created by the inline mixer 29 creates a vortex 48 within the feedstock stream, thereby ensuring that a substantially homogenous mixture is formed within the process vessel 26.

[0193] FIG. 4 illustrates a cross-sectional view of a process vessel 26 according to an embodiment of the present invention. The process vessel 26 of FIG. 4 is similar to that of FIG. 3 except that, in addition to the inline mixer 29, the process vessel 26 includes an impeller 28 adapted to further mix the feedstock material and also to reduce the size of solid particles in the feedstock material upon contact with the blades 49.

[0194] FIG. 5 illustrates a device 50 for the addition of catalyst to a process stream according to an embodiment of the present invention. The device 50 comprises a hopper 51 for holding solid catalyst, with the hopper 51 being in fluid communication with a pipe 52 through which a process stream extracted from a process vessel, mixing vessel or reaction vessel is circulated under the suction created by the inline mixer 29.

[0195] Catalyst from the hopper 51 is drawn into the circulating process stream through a Venturi assembly 53. The mixing conditions created by the inline mixer 29 ensure that the catalyst is dispersed evenly in the process stream, thereby forming a substantially homogenous process stream.

[0196] In FIG. 6 an alternative flowsheet of a method for the production of diesel according to an embodiment of the present invention is illustrated. Feedstock is split into a polymeric material feedstock stream 24 and a biomass feedstock stream 25. Each feedstock stream 24, 25 is introduced into a process vessel 26. The process vessels are sealed with airlock gates 27 and are maintained with a nitrogen atmosphere so as to prevent oxygen from entering the process vessels 26. Each process vessel 26 is maintained at a temperature of 110° C. in order to increase the solubility of the solid particles in the feedstock streams 24, 25 in the medium in the process vessels 26. In this embodiment of the invention, the medium is an ionic liquid, particularly 1-Butyl-3-methylimidazolium chloride.

[0197] The elevated temperature in the process vessels 26 may be maintained using burners, heated jackets or the like. However, in the embodiment of the invention illustrated in FIG. 6, the elevated temperature in the process vessels 26 may initially be achieved using heating apparatus (not shown), however the elevated temperature may be substantially maintained by the fact that the reaction occurring in the process vessels 26 is exothermic. The heating apparatus (not shown) may be periodically used in order to maintain the elevated temperature in the process vessels 26 if the heat generated by the exothermic reaction is insufficient by itself to maintain the elevated temperature.

[0198] In the embodiment of the invention shown in FIG. 6, the elevated temperature within the process vessels 26 results in the evaporation of water contained in the feedstock streams 24, 25. The evaporated water is removed from the process vessels 26 in the form of steam, is passed through a condenser 100 and is then collected in a tank 101.

[0199] The process vessels 26 are agitated using impellers 28, although further agitation is provided using inline mixers 29 that extract material from a lower region of the process vessels 26 and return it to an upper region of the process vessels 26. The inline mixers 29 exert high degrees of suction on the feedstock streams 24, 25 such that even fine, light particles floating on the surface of the liquid in the process vessels 26 are drawn through the inline mixers 29. The high shear conditions created by the inline mixers 29 (along with the elevated temperatures in the process vessels 26) serve to further reduce the size of particles in the feedstock streams 24, 25 and also to form substantially homogenous intermediate feedstock streams 30 that exit the process vessels 26.

[0200] The ionic liquid in the process vessels 26 serves as both a catalyst and a solvent, and organic compounds within the feedstock streams 24, 25 are, over a period of time depending on the type of material in the feedstock streams 24, 25) solubilized or dissolved into the ionic liquid.

[0201] It is envisaged that metallic matter may be present in the plastics feedstock stream 24. It is envisaged that, in this embodiment of the invention, the metallic matter will not be dissolved or solubilized by the ionic liquid, and will instead settle or precipitate to the bottom of the process vessel 26 (due to the difference in density between the metallic matter and the ionic liquid) where it will form a metallic sludge (not shown). This metallic sludge will be collected from the process vessel 26 and treated in order to recover the metallic matter (and particularly precious metals as found in printed circuit boards and similar devices).

[0202] Once sufficient solubilisation of the feedstock streams 24, 25 has occurred so that the intermediate feedstock streams 30 have been formed in the process vessels 26, the intermediate feedstock streams 30 may be introduced to a mixing vessel 33 where the intermediate feedstock streams 30 are combined to form the feed material 34.

[0203] In the embodiment of the invention illustrated in FIG. 6, the feed material 34 contains no more than 30% solids. More preferably, however, the feed material contains substantially no solids (other than unavoidable trace amounts). By minimizing the quantity of solid particles in the feed material, clogging of pipework in the plant by settling or deposited solids may be reduced or eliminated.

[0204] As with the process vessels 26, the mixing vessel 33 is sealed with an airlock gate 35 and is maintained with a nitrogen atmosphere so as to prevent oxygen from entering the mixing vessel 33. The mixing vessel 33 is maintained at a temperature of 110° C. in order to increase the solubility of the solid particles in the intermediate feedstock streams 30 in the carrier oil (in this embodiment, biodiesel) in the mixing vessel 33.

[0205] The mixing vessel 33 is agitated using an impeller 36, although further agitation is provided using an inline mixer 37 that extracts material from a lower region of the mixing vessel 33 and returns it to an upper region of the mixing vessel 33. The inline mixer 37 exerts high degrees of suction on the intermediate feedstock streams 30 such that even fine, light particles floating on the surface of the liquid in the mixing vessel 33 are drawn through the inline mixer 37. The high shear conditions created by the inline mixer 37 (along with the elevated temperature in the mixing vessel 33) serve to further reduce the size of particles (if any) in the intermediate feedstock streams 30 and also to form a substantially homogenous feed material 34 that exits the mixing vessel 33.

[0206] If required, additional ionic liquid and/or lime may be added to the mixing vessel 33 through feeder 102.

[0207] Once a substantially homogenous feed material 34 is formed in the mixing vessel 33, the feed material 34 is introduced to a reaction vessel 38. The reaction vessel 38 is maintained with a nitrogen atmosphere so as to prevent oxygen from entering the reaction vessel 38. The reaction vessel 38 is maintained at a temperature of 180° C. in order to both assist in the catalytic depolymerisation reaction occurring in the reaction vessel 38 and to vaporise at least a portion of the feed material 34 (preferably at least the diesel fraction of the feed material 34), with the vaporised portion of the feed material 34 entering a fractionating column 39 for recovery of the diesel fraction. If present, water is also recovered in the fractionating column 39.

[0208] The recovered diesel (and water if present) is condensed using a cooler 40, and then the diesel may be separated from the water using a separator 41. The recovered diesel may then either be used or may be treated to upgrade the quality of the diesel.

[0209] The temperature in the reaction vessel 38 is maintained by providing a hot oil tank 42 that circulates hot oil through pipes 43 in the reaction vessel 38. In this way, the temperature of the feed material 34 in the reaction vessel 38 may be maintained at a substantially constant temperature, thereby ensuring a consistent reaction rate within the reaction vessel 38.

[0210] The reaction vessel 38 is associated with a high shear mixer 44 that extracts feed material 34 from a lower region of the reaction vessel 38 and returns it to an upper region of the reaction vessel 38. The high shear mixer 44 assists in ensuring that the feed material 34 remains a substantially homogenous mixture.

[0211] As mentioned previously, diesel recovered from the fractionating column 39 may be treated in order to upgrade the quality of the diesel. In one embodiment, the diesel may be treated according to the flowsheet for removing sulphur from diesel as illustrated in FIG. 7.

[0212] In FIG. 7, ionic liquid 103 in the form of 1-Butyl-3-methylimidazolium chloride is added to an upgrading vessel 104. The upgrading vessel 104 is agitated using an impeller 105.

[0213] Diesel 106 is introduced to the upgrading vessel 104 and is maintained in contact with the ionic liquid 103 for a period of time (typically at least one hour, although this will depend on the size of the upgrading vessel, the sulphur content of the diesel and so on). It is envisaged that contact between the ionic liquid 103 and the diesel 106 will result in at least a portion of sulphur (and/or nitrogen) in the diesel 106 being converted into gaseous sulphur dioxide (and/or NO.sub.x). These gaseous compounds are collected as they exit the upgrading vessel 104 and, at least in the case of sulphur dioxide, are converted into a saleable product. In particular, sulphur dioxide may be converted into a fertilizer by contacting the sulphur dioxide with ammonia so as to form ammonium sulphate.

[0214] In addition to the removal of gaseous sulphur dioxide (and/or NO.sub.x), the contact between the ionic liquid 103 and the diesel results in the extraction of sulphur (in the form of sulphur oxide) and organosulphgur (and/or organonitrogen) compounds from the diesel 106 into the ionic liquid 103.

[0215] Following the removal of the sulphur and/or nitrogen compounds from the diesel 106, the mixture of ionic liquid 103 and diesel 106 is transferred from the upgrading vessel 104 to a separation tank 107, where it is heated to an elevated temperature of approximately 200° C. using burners, heated jackets or the like. The elevated temperature has the effect of selectively evaporating the diesel 106 from the ionic liquid 103. Evaporated diesel 108 is then collected and condensed. Ideally, the resulting diesel product will have a sulphur content of no more than 10 ppm.

[0216] Following the removal of diesel 108, the ionic liquid 103 is transferred to a regeneration vessel 109 in which the ionic liquid 103 is heated under vacuum to vaporize any remaining sulphur and/or nitrogen compounds 111, which are then removed from the regeneration vessel 108. Regenerated ionic fluid 110 is then returned to the upgrading vessel 104 for further use.

[0217] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0218] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0219] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.