PROCESS AND PLANT FOR PRODUCING E-FUELS

Abstract

Process and plant for producing a hydrocarbon product boiling in the gasoline boiling range, comprising: upgrading a naphtha containing stream derived from Fischer-Tropsch (FT) synthesis by passing the naphtha containing stream through an aromatization stage comprising contacting the naphtha containing stream with an aluminosilicate zeolite, thereby producing said hydrocarbon product boiling in the gasoline boiling range, and a separate light hydrocarbon gas stream, such as liquid petroleum gas (LPG) stream. The synthesis gas for the FT-synthesis is produced by electrically heated reverse water gas shift (e-RWGS) of a feedstock comprising CO.sub.2 and H.sub.2.

Claims

1. A process for producing a hydrocarbon product boiling in the gasoline boiling range, said process comprising the steps of: i) converting a feedstock comprising CO.sub.2 and H.sub.2 into a synthesis gas in a synthesis gas section, by conducting a reverse water gas shift reaction in a reverse water gas shift (RWGS) unit, for thereby producing said synthesis gas; ii) passing at least a part of the synthesis gas to a synthetic fuel synthesis unit comprising Fischer-Tropsch (FT) synthesis in a FT-synthesis reactor for producing one or more FT-product streams including a FT-condensate stream, optionally also a FT-tail gas stream, and subsequent hydroprocessing of the one or more FT-product streams in one or more hydroprocessing stages, for producing a hydrocarbon product boiling at above 30? C., including a hydrocarbon product boiling in the diesel fuel range, optionally a hydrocarbon product boiling in the jet fuel range, and a naphtha stream; iii) upgrading at least a portion of said naphtha stream and/or at least a portion of the FT-condensate stream, by passing it through an aromatization stage comprising: contacting the at least a portion of said naphtha stream, and/or the at least a portion of the FT-condensate stream with a catalyst comprising an aluminosilicate zeolite, thereby producing said hydrocarbon product boiling in the gasoline boiling range, and a separate light hydrocarbon gas stream; and wherein the aluminosilicate zeolite has a MF1-structure, the temperature is in the range 300-500? C., the pressure is 1-30 bar, and optionally there is addition of hydrogen.

2. Process according to claim 1, wherein in step (iii) the catalyst is incorporated in the aluminosilicate zeolite.

3. Process according to claim 1, wherein in step i) the RWGS unit is conducted in non-selective mode, whereby a catalyst for RWGS, apart from being active for RWGS, is also active for conducting steam reforming and/or methanation.

4. Process according to claim 1, wherein in step i) the feedstock is provided as separate feedstock streams, in which a first feedstock comprises CO.sub.2 and a second feedstock comprises H.sub.2, wherein the feedstock comprising CO.sub.2 is a CO.sub.2-stream comprising 75% vol. or more CO.sub.2, and wherein the feedstock comprising H.sub.2 is a H.sub.2-stream comprising 75% vol. or more H.sub.2.

5. Process according to claim 1, wherein the volume ratio of H.sub.2/CO.sub.2 in the feedstock is between 2.5 and 4.

6. Process according to claim 1, further comprising prior to step i): providing a carbon capture and utilization step (CCU) and deriving thereof the CO.sub.2 of the feedstock in step i), and/or providing a hydrocarbon feed gas and deriving thereof the CO.sub.2 of the feedstock in step i); and/or providing a water (steam) electrolysis step, and deriving thereof the H.sub.2 of the feedstock of step i).

7. Process according to claim 1, comprising adding to step i) a recycle gas stream including one or more of: a portion of the naphtha stream of step ii); an off-gas stream generated from the hydroprocessing stage of step ii); a light hydrocarbon stream; tail gas (FT-tail gas) stream generated in the FT-synthesis of step ii).

8. Process according to claim 1, comprising adding to the synthesis gas section in step i) a hydrocarbon feed gas from an external source, and wherein step i) further comprises: conducting steam reforming of hydrocarbons in a steam reforming unit, for thereby producing said synthesis gas.

9. Process according to claim 3, wherein in step i) further to the RWGS unit being conducted in said non-selective mode: the RWGS-unit is an e-RWGS unit; the temperature of the synthesis gas from the e-RWGS unit is 900? C. or higher; and optionally the e-RWGS unit is operated pressures of 5-20 bar.

10. Process according to claim 1, further comprising: iv) passing at least a portion of the hydrogen from the feedstock of step i) to the hydroprocessing of step ii) and/or the aromatization stage of step iii)

11. Process according to claim 1, further comprising: v) passing at least a portion of said light hydrocarbon gas stream to a hydrogen producing unit (HPU) for producing a hydrogen stream.

12. Process according to claim 1, wherein the one or more hydroprocessing stages in step ii) comprises: hydrodeoxygenation (HDO) and/or hydrocracking (HCR); optionally hydrodewaxing (HDW); optionally also hydrodearomatization (HDA).

13. Process according to claim 11, wherein the HPU in step v) comprises feeding a hydrocarbon feed gas from an external source, optionally also feeding a part of the naphtha stream of step ii).

14. Process according to claim 11, wherein the HPU comprises subjecting said light hydrocarbon gas stream and said hydrocarbon feedstock to: cleaning in a cleaning unit; optionally pre-reforming in a pre-reforming unit; catalytic steam methane reforming in a steam reforming unit; water gas shift conversion in a water gas shift unit; optionally carbon dioxide removal in a CO.sub.2-separator unit; and optionally hydrogen purification in a hydrogen purification unit, and wherein the steam reforming unit of the HPU is: a convection reformer, a tubular reformer, autothermal reformer (ATR), electrically heated steam methane reformer (e-SMR), or combinations thereof.

15. A plant for producing a hydrocarbon product boiling in the gasoline boiling range, comprising: a) a synthesis gas section arranged to at least receive a feedstock comprising CO.sub.2 and H.sub.2 and for producing a synthesis gas, said synthesis gas section comprising: a-1) a reverse water gas shift (RWGS) unit, arranged for operating in non-selective mode by comprising a catalyst which apart from being active for RWGS, is also active for conducting steam reforming and/or methanation; a-2) a water (steam) electrolysis unit for producing said H.sub.2; b) a synthetic fuel synthesis unit arranged for converting said synthesis gas into a hydrocarbon product boiling at above 30? C. including: one or more of a hydrocarbon product boiling in the diesel fuel range, optionally a hydrocarbon product boiling in the jet fuel range, and a naphtha stream; said synthetic fuel synthesis unit comprising: b-1) a FT reactor arranged for receiving the synthesis gas and for outletting one or more FT product streams including a FT-condensate stream, and b-2) a hydroprocessing section arranged downstream said FT reactor for receiving at least a portion of the one or more FT product streams and for producing said hydrocarbon product; the hydroprocessing section optionally also being arranged for receiving a hydrogen stream; optionally, b-3)a bypass conduit for outletting at least a portion of the FT-condensate stream around said hydroprocessing section as a bypass FT-condensate stream; c) an aromatization section comprising a reactor, suitably a fixed bed reactor, containing a catalyst, the catalyst comprising an aluminosilicate zeolite having a MF1-structure, and arranged to receive said naphtha stream or a portion thereof and said bypass FT-condensate stream, for producing said hydrocarbon product boiling in the gasoline boiling range, and for producing a light hydrocarbon gas stream; the aromatization section further being arranged for operating at 300-500? C. and 1-30 bar; optionally, d) a hydrogen producing unit (HPU) arranged to receive said light hydrocarbon gas stream and optionally arranged to also receive a hydrocarbon feed gas from an external source.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0204] FIG. 1 shows a process/plant layout according to an embodiment of the invention where a feedstock comprising CO.sub.2 and H.sub.2 is converted to e-fuels.

[0205] FIG. 2 shows a process/plant layout according to another embodiment of the invention where a feedstock comprising CO.sub.2 and H.sub.2 is converted to e-fuels and a light hydrocarbon gas stream generated in the process is used for producing hydrogen in a dedicated hydrogen producing unit.

DETAILED DESCRIPTION

[0206] With reference to the FIG. 1, the process/plant 10 converts a feedstock comprising carbon dioxide stream 5 and hydrogen stream 7 and optionally also a hydrocarbon feed gas from an external source, such as natural gas 9 and internal recycle streams 25, 31, 33, 37 produced in the process as described below, into synthesis gas 11 and then to the hydrocarbon products (synfuels) as the e-fuels: diesel 17, jet fuel 19 and gasoline 23. The CO.sub.2 stream 5 is derived from carbon capture, which is schematically represented herein as 30, of a CO.sub.2 stream 1 derived or emitted from e.g. another source, such as a power plant. Thus, the CO.sub.2 of the feedstock is e.g. derived from carbon-capture and utilization (CCU). Water (steam) 3 passes through an electrolysis unit 40, such as a solid oxide electrolysis cell (SOEC) unit when using steam, or an alkaline/PEM electrolysis unit when using liquid water, powered by electricity 40 generated from a renewable source such as wind, hydropower or solar energy. Thereby the hydrogen stream 7 is generated.

[0207] The process/plant comprises a synthesis gas section 50 and a synthetic fuel synthesis unit 60, i.e. FT synthesis section. The synthesis gas section 50 comprises an electrically heated reverse water gas shift unit (e-RWGS), optionally e-reforming (e-SMR), not shown, powered by electricity 50, which also is generated from a renewable source as explained above. The synthetic fuel synthesis unit 60 comprises a FT reactor 60 producing one or more FT-product streams including a FT-condensate stream 13 and which at least a part thereof is treated in downstream hydroprocessing section 60, i.e. Product Workup Unit, PWU.

[0208] From the synthetic fuel synthesis unit 60 the hydrocarbon product diesel 17 and jet fuel 19 are produced, along with a FT tail gas (tail gas) 31 withdrawn from the FT reactor 60 which may be recycled to the synthesis gas section 50 after being subjected to a pretreatment (not shown). The hydroprocessing section 60 may comprise a fractionation unit (not shown) downstream the one or more hydroprocessing units arranged therein. From the synthetic fuel synthesis unit 60 a naphtha stream 21 is produced of which a portion 33 may be recycled to the synthesis gas section 50. From the hydroprocessing section 60 an off-gas stream 37 may be withdrawn and also recycled to synthesis gas section 50. The naphtha stream 21 is highly paraffinic and has a low octane number (RON of about 40). The naphtha stream 21 as well as an optional bypass FT-condensate stream 15 is passed to an aromatization stage in unit 70 (catalytic reactor 70), thereby upgrading the naphtha and producing a gasoline product 23 having a high octane number, for instance RON above 90. The bypass FT-condensate stream may also be combined (stream 15) with the naphtha stream 21 prior to entering the aromatization unit 70. From the aromatization unit 70 a light hydrocarbon gas stream 25, such as liquid petroleum gas (LPG) stream, is produced, which may be recycled as stream 25 to synthesis gas unit 50. A portion (not shown) of hydrogen stream 7 is suitably used as hydrogen source for the hydroprocessing 60 and/or downstream aromatization 70.

[0209] With reference to FIG. 2, the process/plant is as in FIG. 1 but now also include light hydrocarbon stream being passed as stream 25 to a hydrogen producing unit (HPU) 80 for producing hydrogen stream 29 (make-up hydrogen gas). A hydrocarbon feed gas from an external source, such as natural gas 27, or naphtha 21 produced in the process may be used to assist in the hydrogen production (not shown). By using the light hydrocarbon gas stream 25, the need of e.g. natural gas 27 therein is drastically reduced. The produced make-up hydrogen gas 29 may be used for instance as part of the feedstock to the synthesis gas section 50, and/or as make up hydrogen gas in the hydroprocessing section 60, and/or for use within the HPU itself, for instance in a cleaning unit therein (not shown), or as an end product. The HPU 80 includes an e-SMR powered by electricity 80 generated from a renewable source as explained above. Thereby, higher flexibility is achieved, as yet another internal source of hydrogen, apart from hydrogen stream 7, and which can be integrated in the process/plant or used as end-product, is provided. Carbon dioxide from a carbon dioxide removal step (not shown) in the HPU 80, may also be used as part of the feedstock to the syngas section 50, along with stream 5.