METHOD FOR PRODUCING SUSTAINABLE FUEL VIA CARBON MONOXIDE

Abstract

Subject of the invention is a method for producing sustainable fuel, comprising the steps (i) converting CO.sub.2 into CO using a reverse water gas shift catalyst, (ii) converting CO from step (i) into C.sub.1-C.sub.6 hydrocarbons using a Fischer-Tropsch catalyst, and (iii) converting C.sub.1-C.sub.6 hydrocarbons from step (ii) into aromatics using a zeolite-based catalyst, further comprising a cooling step in which CO from step (i) is cooled before being converted in step (ii).

Claims

1. A method for producing sustainable fuel, comprising the steps: (i) converting CO.sub.2 into CO using a reverse water gas shift catalyst, (ii) converting CO from step (i) into C.sub.1-C.sub.6 hydrocarbons using a Fischer-Tropsch catalyst, and (iii) converting C.sub.1-C.sub.6 hydrocarbons from step (ii) into aromatics using a zeolite-based catalyst, wherein the C.sub.1-C.sub.6 hydrocarbons comprise ethylene, propylene and/or butylene, further comprising a cooling step in which CO from step (i) is cooled before being converted in step (ii), wherein the CO from step (i) is cooled from a temperature of 500 C. to a temperature of 350 C. before being converted in step (ii), wherein step (ii) is performed at a temperature of 200 to 350 C.

2. (canceled)

3. The method according to claim 1, wherein step (i) is performed at a temperature of 250 to 1000 C.

4. (canceled)

5. The method according to claim 1, wherein H.sub.2O is produced in step (i) to yield a mixture comprising CO and H.sub.2O, wherein the H.sub.2O is at least partially separated from the CO in the cooling step.

6. (canceled)

7. The method according to claim 1, wherein the reverse water gas shift catalyst comprises Fe, Co, Cu, Cr, Ni, Ir, Mn or mixtures thereof.

8. The method according to claim 1, wherein the Fischer-Tropsch catalyst comprises Fe and/or Co, preferably Co.

9. The method according to claim 1, wherein the zeolite-based catalyst in step (iii) comprises an MFI-type zeolite, a CHA-type zeolite, a BEA-type zeolite, a MOR-type zeolite, an FAU-type zeolite, an MEL-type zeolite, an FER-type zeolite, an MTT-type zeolite, a TON-type zeolite, an ERI-type zeolite, an MTW-type zeolite, an MWW-type zeolite or a mixture thereof.

10. The method according to claim 1, wherein another metal-modified zeolite-based catalyst is present in step (i).

11. The method according to claim 1, wherein step (ii) additionally produces saturated C7+ hydrocarbons, preferably saturated C8+ hydrocarbons.

12. (canceled)

13. The method according to claim 1, wherein in step (i) a feed comprising the CO.sub.2 is fed to the reverse water gas shift catalyst, wherein the feed is substantially free of CO.

14. The method according to claim 1, wherein in step (i) the CO.sub.2 is reacted with H.sub.2 at a temperature of 250 to 1000 C. using a reverse water gas shift catalyst which comprises Ni/Al.sub.2O.sub.3 to yield a mixture comprising CO and H.sub.2O, wherein the H.sub.2O is at least partially separated from the CO in a subsequent cooling step before the CO is converted in step (ii), wherein in step (ii) CO from step (i) is reacted with H.sub.2 using a Fischer-Tropsch catalyst which comprises Co to yield saturated C8+ hydrocarbons and unsaturated hydrocarbons which comprise at least one of ethylene, propylene and/or butylene, and wherein in step (iii) the zeolite-based catalyst comprises an MFI-type zeolite or a BEA-type zeolite.

15. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0078] FIG. 1 shows an exemplary reactor system in which a method according to the present invention can be carried out.

EXEMPLARY EMBODIMENT

[0079] The present invention is further described with reference to the accompanying FIG. 1 which shows an exemplary reactor system 10. The reactor system 10 has two reactors, namely a first reactor 1 and a second reactor 2, which are in fluid communication with each other. A first feed 3 is fed to the first reactor 1. Feed 3 comprises CO.sub.2 and H.sub.2, and depending on the source of the CO.sub.2 potentially minor amounts of CO (typically however 0% CO) and light hydrocarbons. The first reactor 1 contains a first catalyst bed 4 which contains Ni/Al.sub.2O.sub.3 as a reverse water gas shift catalyst. The first reactor bed 1 is operated at elevated temperatures between 25 and 1000 C. and absolute pressures between 0.1 and 10 MPa. The thereby produced CO and H.sub.2O are contained in a first product 5, together with unreacted H.sub.2 and potentially unreacted CO.sub.2. Methane (CH.sub.4) in low amounts may also be produced in reactor 1, in which case the first product 5 additionally contains CH.sub.4. The first product 5 is withdrawn from reactor 1 and is sent to reactor 2. In-between reactor 1 and reactor 2, a cooling device 6 may be arranged. The cooling device 6 cools the first product 5 to the reaction temperature of the second reactor 2. The cooling device 6 further separates at least some of the H.sub.2O produced in the first reactor 1 to give the second feed 7 which is fed to the second reactor 2. The second feed 7 contains CO, H.sub.2 and potentially CO.sub.2 and/or CH.sub.4. The second reactor 2 contains a second catalyst bed 8 which contains a Co-based Fischer-Tropsch catalyst (metallic Co on support) and an HZSM-5 zeolite catalyst. The second reactor 2 is operated at elevated temperatures between 20 and 500 C. and absolute pressures between 0.1 and 5 MPa. In the second reactor 2, unreacted H.sub.2 and CO generated from the first reactor are converted by the Fischer-Tropsch catalyst to C.sub.1-C.sub.6 hydrocarbons, which contain C.sub.2-C.sub.4 alkenyls, and additionally to saturated C7+ hydrocarbons. The C.sub.1-C.sub.6 hydrocarbons are converted to aromatics by the HZSM-5 zeolite catalyst. As a result, a second product 9 is obtained which contains long hydrocarbons and aromatics, and potentially residual CO, H.sub.2, CO.sub.2 and/or CH.sub.4. The second product 9 can be withdrawn from the second reactor as the overall product, i.e., as a sustainable (raw) fuel for further use or refinement thereof.

LIST OF REFERENCE SIGNS

[0080] 1: First reactor [0081] 2: Second reactor [0082] 3: First feed [0083] 4: First catalyst bed [0084] 5: First product [0085] 6: Cooling device [0086] 7: Second feed [0087] 8: Second catalyst bed [0088] 9: Second product [0089] 10: Reactor system

FURTHER DISCLOSURE

[0090] The present invention further provides the following items: [0091] 1. A method for producing sustainable fuel, comprising the steps: [0092] (i) converting CO.sub.2 into CO using a reverse water gas shift catalyst, [0093] (ii) converting CO from step (i) into C.sub.1-C.sub.6 hydrocarbons using a Fischer-Tropsch catalyst, and [0094] (iii) converting C.sub.1-C.sub.6 hydrocarbons from step (ii) into aromatics using a zeolite-based catalyst. [0095] 2. The method according to item 1, wherein in step (i) the CO.sub.2 is at least partially reacted with H.sub.2, and/or wherein in step (ii) the CO is at least partially reacted with H.sub.2. [0096] 3. The method according to item 1 or 2, wherein the reverse water gas shift catalyst comprises Fe, Co, Cu, Cr or Ni. [0097] 4. The method according to any of the preceding items, wherein the Fischer-Tropsch catalyst comprises metallic Fe and/or metallic Co, preferably metallic Co. [0098] 5. The method according to any of the preceding items, wherein the zeolite-based catalyst in step (iii) comprises an MFI-type zeolite, a CHA-type zeolite, a BEA-type zeolite, a MOR-type zeolite, an FAU-type zeolite, an MEL-type zeolite, an FER-type zeolite, an MTT-type zeolite, a TON-type zeolite, an ERI-type zeolite, an MTW-type zeolite, an MWW-type zeolite or a mixture thereof. [0099] 6. The method according to any of the preceding items, wherein another metal-modified zeolite-based catalyst is present in step (i). [0100] 7. The method according to any of the preceding items, wherein step (ii) additionally produces saturated C7+ hydrocarbons, preferably saturated C8+ hydrocarbons. [0101] 8. The method according to any of the preceding items, wherein the C.sub.1-C.sub.6 hydrocarbons comprise ethylene, propylene and/or butylene. [0102] 9. The method according to any of the preceding items, wherein step (i) is performed at a temperature of 250 to 1000 C. [0103] 10. The method according to any of the preceding items, further comprising a cooling step in which CO from step (i) is cooled before being converted in step (ii). [0104] 11. The method according to item 10, wherein H.sub.2O is produced in step (i) to yield a mixture comprising CO and H.sub.2O, wherein the H.sub.2O is at least partially separated from the CO in the cooling step. [0105] 12. The method according to any of the preceding items, wherein in step (i) a feed comprising the CO.sub.2 is fed to the reverse water gas shift catalyst, wherein the feed is substantially free of CO. [0106] 13. The method according to any of the preceding items, [0107] wherein in step (i) the CO.sub.2 is reacted with H.sub.2 at a temperature of 250 to 1000 C. using a reverse water gas shift catalyst which comprises Ni/Al.sub.2O.sub.3 to yield a mixture comprising CO and H.sub.2O, [0108] wherein the H.sub.2O is at least partially separated from the CO in a subsequent cooling step before the CO is converted in step (ii), [0109] wherein in step (ii) CO from step (i) is reacted with H.sub.2 using a Fischer-Tropsch catalyst which comprises Co to yield saturated C8+ hydrocarbons and unsaturated hydrocarbons which comprise at least one of ethylene, propylene and/or butylene, and [0110] wherein in step (iii) the zeolite-based catalyst comprises an MFI-type zeolite or a BEA-type zeolite. [0111] 14. Use of sustainable fuel obtained by a method according to any of items 1 to 13 as aviation fuel. [0112] 15. Sustainable fuel obtainable by a method according to any of items 1 to 13.