Apparatus for providing a synthesis gas mixture of at least carbon dioxide and hydrogen

Abstract

To provide an apparatus for supplying a synthesis gas mixture of at least carbon dioxide and hydrogen.SOLUTION: Wherein the device (10) comprises a branching device (13) for branching the mass flow of at least carbon dioxide into a first and a second partial mass flow, a partial mass flow turbine (14) for expanding the first partial mass flow, a first mixing device (16) for mixing the expanded first partial mass flow with at least the mass flow of hydrogen, a compression device (17) for compressing the mixture of at least carbon dioxide and hydrogen to a third pressure level, and a bypass line (20) through which the second partial mass flow is conducted past the partial mass flow turbine (14), the first mixing device (16) and the compression device (17) in the direction of a second mixing device (21) in order to mix the second partial mass flow with the mixture compressed by the compression device (17) in the region of the second mixing device (21). And a bypass line (20).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for providing a synthetic gas mixture of at least carbon dioxide and hydrogen, in particular for producing synthetic fuels. [Background technology]

[0002] For example, to produce synthetic fuels, such as methane or methanol, hydrogen and carbon dioxide are required. A mixture of at least hydrogen and carbon dioxide, also known as a synthesis gas mixture, must be supplied at a certain pressure level to the plant where the synthetic fuel is ultimately produced.

[0003] Thus, an apparatus for producing synthetic fuels, such as methane or methanol, operates at a pressure level between 30 and 70 bar. A synthesis gas mixture containing at least carbon dioxide and hydrogen must be supplied at this pressure level.

[0004] Carbon dioxide is preferentially supplied by a carbon dioxide supply at a first pressure level, and hydrogen is preferentially supplied by a hydrogen supply at a second pressure level.

[0005] The hydrogen supply device may be, for example, an electrolyzer that supplies hydrogen using electricity generated from a renewable energy source. The hydrogen supplied by the hydrogen supply device is supplied at a second pressure level.

[0006] Carbon dioxide is supplied at a first pressure level, and the carbon dioxide supply may be, for example, a carbon capture and storage (CCS) plant or a direct air capture (DAC) plant.

[0007] The first pressure level at which gaseous carbon dioxide is supplied is typically higher than the second pressure level at which hydrogen is supplied, so that the second pressure level at which gaseous hydrogen is supplied corresponds to atmospheric pressure (1 bar), and the first pressure level at which gaseous carbon dioxide is supplied may be 30 bar or more.

[0008] In particular, if hydrogen gas starting from the second pressure level is compressed to the pressure level at which the apparatus for producing synthetic fuel operates, the low molecular weight of hydrogen gas increases the technical installation costs of the apparatus, in particular, a large number of compressor stages are required, and a relatively large amount of energy is required to compress the hydrogen gas.

[0009] There is a need to provide a synthesis gas mixture of at least carbon dioxide and hydrogen at lower technical equipment costs and lower energy requirements at the pressure levels required, in particular by equipment for producing synthetic fuels. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] U.S. Patent No. 8,961,909 Summary of the Invention [Problem to be solved by the invention]

[0011] Starting from this, the invention is based on the object of creating a new type of device for supplying a synthesis gas mixture of at least carbon dioxide and hydrogen. [Means for solving the problem]

[0012] This problem is solved by a device according to claim 1.

[0013] The apparatus according to the present invention comprises a branching device for branching a mass flow of at least carbon dioxide fed to the apparatus into a first partial mass flow of at least carbon dioxide and a second partial mass flow of at least carbon dioxide. The apparatus according to the present invention further comprises a partial mass flow turbine for expanding the at least first partial mass flow of carbon dioxide. The apparatus according to the present invention further comprises a first mixing device for mixing the at least first partial mass flow of carbon dioxide expanded by the partial mass flow turbine with a mass flow of at least hydrogen fed by the apparatus. The apparatus according to the present invention further comprises a compression device for compressing the mixture of at least carbon dioxide and hydrogen fed by the first mixing device to a third pressure level. The apparatus according to the present invention further comprises a bypass line via which the second partial mass flow of at least carbon dioxide can be guided through the partial mass flow turbine, the first mixing device and the compression device towards the second mixing device, so that in the region of the second mixing device, the second partial mass flow of at least carbon dioxide guided via the bypass line is mixed with the mixture of at least carbon dioxide and hydrogen compressed by the compression device.

[0014] In the device according to the invention for supplying a synthesis gas mixture of at least carbon dioxide and hydrogen, a mass flow of at least carbon dioxide supplied by a carbon dioxide supply device is divided into partial mass flows, a first partial mass flow is mixed for expansion via a partial mass flow turbine and then mixed with gaseous hydrogen, in particular supplied by a hydrogen supply device, in the region of a first mixer, and then this mixture is compressed in a compressor.

[0015] By mixing the hydrogen gas supplied to the device with the first partial mass flow of carbon dioxide supplied to the device, a gas mixture having a significantly higher molecular weight than the hydrogen gas itself is provided, and this mixture of carbon dioxide and hydrogen can be compressed by a compressor with lower technical equipment costs and at lower costs. Fewer compressor stages are required to compress the mixture of hydrogen gas and the first partial mass flow of carbon dioxide than are required to compress hydrogen gas itself. Furthermore, the polytropic expansion of the first partial mass flow upstream of the compressor provides a temperature level for the hydrogen and carbon dioxide mixture to be compressed, which makes it possible to compress the mixture with low power requirements.

[0016] In particular, the second partial mass flow of carbon dioxide supplied to the system by the carbon dioxide supply device is directed via a bypass line through the partial mass flow turbine, the first mixer and the compressor in the direction of the second mixer, and the second partial mass flow downstream of the compressor is mixed with the mixture compressed in the compressor, which is also advantageous in order to keep the technical equipment costs and energy requirements in the region of the compressor as low as possible.

[0017] The device according to the invention for providing a synthesis gas mixture of at least carbon dioxide and hydrogen allows for the efficient provision of a synthesis gas mixture of at least carbon dioxide and hydrogen, in particular for the production of synthetic fuels at low energy costs and low technical equipment costs.

[0018] Preferably, the apparatus according to the invention comprises a total mass flow turbine for expanding the total mass flow of at least the carbon dioxide fed to the apparatus at a predetermined pressure level that depends on the pressure level in the bypass line, which also serves to provide a synthesis gas mixture at a defined pressure level with minimal technical equipment costs and low energy requirements.

[0019] Preferably, the apparatus according to the invention comprises a heating device arranged upstream of the partial mass flow turbine for heating the first partial mass flow, which also serves to provide the synthesis gas mixture at the desired pressure level, preferably with low technical equipment costs and preferably low energy costs. [Brief explanation of the drawings]

[0020] [Figure 1] An apparatus according to the invention for providing a synthesis gas mixture of at least carbon dioxide and hydrogen, in particular for producing synthetic fuels. [Figure 2] This is a further development of the device in Figure 1. DETAILED DESCRIPTION OF THE INVENTION

[0021] Preferred further developments of the invention can be seen from the subclaims and the following description. Preferred embodiments of the invention will now be described in detail with reference to the drawings, but the invention is not limited thereto.

[0022] 1 shows very diagrammatically a block diagram of an apparatus 10 according to the invention for supplying a synthesis gas mixture of at least carbon dioxide and hydrogen, in particular for producing synthetic fuels, in an apparatus for producing synthetic fuels not shown in particular. In particular, a synthesis gas mixture is provided which can be used to produce methane CH4 or methanol CH3OH.

[0023] The device 10 according to the invention is supplied with at least a mass flow of carbon dioxide at a first pressure level p1 and at least a mass flow of hydrogen at a second pressure level p2.

[0024] 1, the hydrogen supply device 11 supplies at least gaseous hydrogen H2 at a second pressure level p2. The hydrogen H2 supplied from the hydrogen supply device 11 may also contain water vapor H2O and oxygen O2. The hydrogen supply device 11 may be, for example, an electrolysis device that produces hydrogen using electricity generated from a renewable energy source such as solar energy or wind energy.

[0025] In Figure 1, a carbon dioxide supply unit 12 supplies gaseous carbon dioxide CO2 at a first pressure level p1. The carbon dioxide supply unit 12 may be a CCS plant or a DAC plant.

[0026] The apparatus 10 for providing a synthesis gas mixture of at least carbon dioxide and hydrogen according to the invention comprises, in the exemplary embodiment of FIG. 1 , a branching device 13 for branching a mass flow provided to the apparatus 10 at a first pressure level p1 of at least carbon dioxide into a first partial mass flow and a second partial mass flow.

[0027] A further component of the device 10 according to the invention for providing a synthesis gas mixture of at least carbon dioxide and hydrogen is a partial mass flow turbine 14 used for the polytropic expansion of at least a first partial mass flow of carbon dioxide, which is expanded in the turbine 14, which drives a generator 15 used to generate electrical energy.

[0028] The device 10 according to the invention for providing a synthesis gas mixture of at least carbon dioxide and hydrogen further comprises a first mixing device 16, in the exemplary embodiment of FIG. 1 , in which the first partial mass flow expanded in the turbine 14 of at least carbon dioxide is mixed with hydrogen provided to the device 10 at a second pressure level p2.

[0029] Furthermore, the device 10 according to the invention for supplying a synthesis gas mixture of at least carbon dioxide and hydrogen comprises a compression device 17 which serves to compress the mixture supplied by the mixer 16 to a third pressure level p3.

[0030] 1 shows multiple parallel-connected compressors 18, with each of two compressors 18 driven by a common motor 19. The number of compressors 18 in the compression unit 17 is purely exemplary. The interconnection of the compressors 18 in the compression unit 17 is purely exemplary in nature. Thus, the compressors 18 may also be connected in series.

[0031] The apparatus according to the invention 10 for supplying a synthesis gas mixture of at least carbon dioxide and hydrogen further comprises a bypass line 20, via which the second partial mass flow of carbon dioxide branched off in the region of the branching device 13 is led through the partial mass flow turbine 14, the first mixer 16 and the compressor 17 in the direction of the second mixer 21, where the second partial mass flow led via the bypass line 20 to the region of the second mixer 21 is mixed with the mixture of the first partial mass flow and hydrogen compressed by the compressor 17. As already explained, the branching device 13 is used to branch the mass flow of at least gaseous carbon dioxide fed to the apparatus 10 into a first partial mass flow led via the partial mass flow turbine 14 and a second partial mass flow led via the bypass line 20.

[0032] The branching device 13 comprises at least one valve 22, 23, and via the open position of the at least one valve 22, 23, it is possible to adjust the branching of the mass flow of at least carbon dioxide supplied to the device 10 into two partial mass flows. Two valves 22, 23 are shown in Figure 1 of the branching device 13. The branching device may also comprise only a single valve 22, preferably in the region of the bypass line 20.

[0033] The first partial mass flow may be between 25% and 75% of the total mass flow of at least carbon dioxide supplied to the apparatus 10, and the second partial mass flow may be between 75% and 25%, with the sum of both partial mass flows being 100%.

[0034] Alternatively, of the total mass flow of at least carbon dioxide supplied to the device 10, the first partial mass flow may be between 30% and 70% and the second partial mass flow may be between 70% and 30%, or the first partial mass flow may be between 40% and 60% and the second partial mass flow may be between 60% and 40%.

[0035] In particular, the pressure level in the bypass line 20 is set to be 0.1 bar to 1 bar higher than the third pressure level p3 of the mixture compressed in the compressor 17 immediately downstream of the compressor 17 or in the region of the second mixer 21.

[0036] In particular, the pressure in the bypass line 20 is 0.1 bar to 0.6 bar, or 0.1 bar to 0.5 bar, or 0.2 bar to 0.6 bar, or 0.2 bar to 0.5 bar higher than the third pressure level p3 of the mixture compressed in the compressor 17 immediately downstream of the compressor 17 or in the region of the second mixer 21.

[0037] In Figure 1, the only pressure losses occur in the region of each valve arranged in the flow path and in each flow line between the separator 13 and the outlet of the bypass line 20 to the second mixer 21. This results in the first pressure level p1 at which the carbon dioxide is supplied in Figure 1 being slightly higher than the pressure level in the bypass line 20 immediately downstream of the compressor 17.

[0038] 2 shows a further development of the device 10 according to the invention for the case in which the first pressure level p1 is significantly higher than the desired pressure level in the bypass line 20 and therefore significantly higher than the third pressure level p3. In this case, the device according to the invention comprises a total mass flow turbine 24. The total mass flow of at least carbon dioxide fed to the device 10 is directed via the total mass flow turbine 24 upstream of the branching device 13. In FIG. 2, a scrubbing device 25 is connected between the total mass flow turbine 24 and the branching device 13 for scrubbing the carbon dioxide. A valve 29 regulates the mass flow through the total mass flow turbine 24.

[0039] The branching device 13 of FIG. 2 similarly branches the mass flow of at least carbon dioxide supplied to the device 10 into a first partial mass flow and a second partial mass flow, but downstream of the total mass flow turbine 24 at a predetermined pressure level p4 lower than the first pressure level p1.

[0040] The pressure level p4 in the region of the branching device 13 depends on the desired pressure level in the bypass line 20 and is slightly higher than the third pressure level p3.

[0041] 1 and 2 further show a heating device 26 which serves to heat the first partial mass flow to be led through the partial mass flow turbine 14 immediately upstream of the partial mass flow turbine 14 and therefore downstream of the branching device 13. This heating device 26 is preferably a heat exchanger operatively connected to the compression device 17 in order to utilize the heat generated in the area of ​​the compression device 17 in the area of ​​the heating device 26.

[0042] 1 and 2, a check valve 27 is connected between the hydrogen supply device 11 and the first mixing device 16. Additionally, FIGS. 1 and 2 show a condensate discharge line 28.

[0043] The exemplary embodiment of FIG. 2 also differs from the exemplary embodiment of FIG. 1 by the number of compressors 18 in the region of the compression device 17 .

[0044] The present invention advantageously enables the provision of a compressed synthesis gas mixture of at least carbon dioxide and hydrogen, particularly at pressure levels required by apparatus for producing synthetic fuels. The compressed synthesis gas mixture of at least carbon dioxide and hydrogen can be provided with low technical equipment costs and low energy requirements.

[0045] It is important to split the total mass flow of carbon dioxide fed to the device 10 into a first partial mass flow and a second partial mass flow, the first partial mass flow being conducted via a partial mass flow turbine 14 and mixed with the hydrogen fed to the device 10 in the region of a first mixer 16. The second partial mass flow passes through the partial mass flow turbine 14 and a compressor 17 via a bypass line 20 and is conducted in the direction of a second mixer 21, where it is mixed with the mixture of the first partial mass flow and hydrogen compressed in the compressor 14. [Explanation of symbols]

[0046] 10. Apparatus for supplying synthesis gas mixtures 11 Hydrogen supply device 12 Carbon dioxide supply device 13 Branching device 14 Partial Mass Flow Turbine 15. Generator 16 First mixing device 17 Compression device 18 Compressor 19 Motor 20 Bypass Line 21 Second mixing device 22 Valves 23 Valve 24 Total Mass Flow Turbine 25 Cleaning equipment 26 Heating device 27 Check valve 28 Discharge Line 29 Valve

Claims

1. 1. An apparatus (10) for supplying a synthesis gas mixture of at least carbon dioxide and hydrogen, in particular for producing a synthetic fuel, the apparatus (10) being supplied with a mass flow of at least carbon dioxide at a first pressure level and a mass flow of at least hydrogen at a second pressure level, a branching device (13) for branching at least the mass flow of carbon dioxide into a first partial mass flow and a second partial mass flow; a partial mass flow turbine (14) for expanding at least said first partial mass flow of carbon dioxide; a first mixer (16) for mixing the first partial mass flow of at least carbon dioxide expanded by the partial mass flow turbine (14) with a mass flow of at least hydrogen; a compressor (17) for compressing the mixture of at least carbon dioxide and hydrogen provided by the first mixer (16) to a third pressure level; a bypass line (20) via which at least a second partial mass flow of carbon dioxide is guided past a partial mass flow turbine (14), a first mixer (16) and a compressor (17) in the direction of a second mixer (21), whereby in the region of the second mixer (21) the at least second partial mass flow of carbon dioxide guided via the bypass line (20) is mixed with the mixture compressed by the compressor (17).

2. 2. The apparatus according to claim 1, wherein the branching device (13) is configured to branch the mass flow of at least carbon dioxide into a first partial mass flow corresponding to 25% to 75% of the total mass flow of at least carbon dioxide fed to the apparatus (10) and a second partial mass flow corresponding to 75% to 25%.

3. 3. The apparatus according to claim 2, wherein the first partial mass flow corresponds to 30% to 70% and the second partial mass flow corresponds to 70% to 30% of the total mass flow of at least carbon dioxide fed to the apparatus (10), or the first partial mass flow corresponds to 40% to 60% and the second partial mass flow corresponds to 60% to 40%.

4. The device according to any one of claims 1 to 3, wherein the branching device (13) comprises at least one valve (22, 23).

5. The device according to any one of the preceding claims, wherein the pressure level in the bypass line (20) is between 0.1 bar and 1 bar higher than the third pressure level.

6. 6. The apparatus of claim 5, wherein the pressure level of the bypass line (20) is between 0.1 bar and 0.7 bar, or between 0.1 bar and 0.6 bar, or between 0.2 bar and 0.6 bar, or between 0.2 bar and 0.5 bar higher than the third pressure level.

7. 7. The apparatus according to claim 5 or 6, comprising a total mass flow turbine (24) for expanding the total mass flow of at least carbon dioxide supplied to the apparatus (10) at the first pressure level to a predetermined pressure level that depends on the pressure level of the bypass line (20).

8. The device according to any one of the preceding claims, comprising a heating device (26) arranged upstream of the partial mass flow turbine (14) for heating the first partial mass flow.

9. 9. The apparatus according to claim 8, wherein the heating device (26) is a heat exchanger that utilizes waste heat from the compression device (17) to heat the first partial mass flow.

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