Method and apparatus for cryogenic separation of CO2-containing gas to produce CO2-rich fluid
A multi-stage compression and distillation process at low temperatures efficiently separates CO and CO2 from gas mixtures, producing high-purity CO-rich fluids while optimizing energy recovery.
Patent Information
- Application Number
- JP2024565952
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-07-29
- Filing Date
- 2023-05-16
- Publication Date
- 2025-05-20
AI Technical Summary
Existing methods for separating carbon monoxide (CO) and carbon dioxide (CO2) from gas mixtures are inefficient at low temperatures, particularly in the context of oxy-combustion processes, leading to suboptimal production of CO-rich fluids.
A process involving multi-stage compression, cooling, and partial condensation followed by distillation to separate CO2 and CO-rich fluids at low temperatures, utilizing heat exchangers and turbines to optimize separation efficiency.
The process effectively produces high-purity CO-rich fluids by efficiently separating CO2 and lighter components, enhancing energy recovery and reducing operational costs.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention is 2 The gas containing CO is separated at low temperatures. 2 The present invention relates to a process and apparatus for producing a CO rich fluid. 2 and carbon monoxide, hydrogen, nitrogen, oxygen or methane, CO 2 and at least one lighter component.
[0002] In particular, the process treats gases resulting from combustion, e.g., an oxy-combustion process, to produce CO 2 rich products, e.g., at least 80 mol % CO 2 , in practice further comprising at least 90 mol % CO 2 A product containing: [Background technology]
[0003] CO 2 Gas containing, for example, H 2 PSA or CO 2 It is waste gas from PSA.
[0004] Cryogenic separation operates at temperatures below 0°C, and indeed even below -40°C. Summary of the Invention [Means for solving the problem]
[0005] According to the present invention, CO 2 The gas containing CO is separated at low temperatures. 2 A process for producing a CO rich fluid comprising: 2 and CO 2 A gas containing at least one lighter component is compressed in a compressor comprising at least two stages, the gas is first cooled in a cooler downstream of the last of the stages and then cooled to ambient temperature by heat exchange with water or vice versa and then cooled in a first heat exchanger, the gas cooled in the first heat exchanger being separated at low temperature by partial condensation to produce CO2 is abundant and CO 2 Fluids depleted of lighter components and CO 2 is deficient and CO 2 It produces gases rich in lighter compounds and CO 2 The lean gas is heated first in a first heat exchanger and then in a cooler before being expanded in a turbine and CO 2 The CO-rich liquid is separated by distillation to produce at least one CO 2 A process is provided for forming a fluid rich in
[0006] Other optional features include: At least one CO 2 The CO-rich fluid is a liquid, and 2 At least a portion of the rich fluid is vaporized in a first heat exchanger; At least one vaporized CO 2 The rich fluid is compressed in a compressor driven by a turbine, CO 2 The CO2-rich liquid is expanded and sent to the top of a stripping column and at least one CO 2 the rich fluid being the bottoms from the strip column; CO 2 The rich liquid is sent to the top of the wash column, and the liquid from the wash column is fed to a distillation column; The top gas from the distillation column is compressed in a compressor driven by a turbine, CO 2 The depleted gas enters the cooler at a temperature higher than the ambient temperature, e.g., higher than 30°C. The gases to be separated are separated by partial condensation (S) and CO 2 The resulting mixture is then cooled to room temperature to produce a depleted gas and also liquid, which is separated by distillation in a distillation column, preferably CO. 2 CO is a CO-rich liquid. 2 producing a fluid rich in At least a portion of the cold is provided by a closed refrigeration cycle including at least one cycle compressor driven by a turbine; At least one CO 2 The rich fluid is a gas that is heated in the first heat exchanger before being compressed.
[0007] According to another aspect of the present invention, CO 2 The gas containing CO is separated at low temperatures. 2 1. An apparatus for producing a CO-rich fluid, comprising: a compressor including at least two stages, a cooler, a water cooler, a first heat exchanger, a phase separator, a turbine and at least one distillation column; 2 and CO 2 means for delivering gas containing at least one lighter component to a compressor including at least two stages; means for delivering compressed gas from the compressor to be cooled by a cooler and a water cooler; means for delivering the gas cooled by the cooler and the water cooler to a first heat exchanger; and 2 is abundant and CO 2 Fluids depleted of lighter components and CO 2 is deficient and CO 2 means for directing the gas cooled in the first heat exchanger to a phase separator to form a gas enriched in lighter components; and means for directing the gas cooled in the first heat exchanger to a phase separator to form a gas enriched in lighter components, the gas being heated first in the first heat exchanger and then in the cooler. 2 a means for sending the CO depleted gas heated by the cooler to be expanded by the turbine; 2 means for delivering the depleted gas; and at least one CO 2 and separating the CO from the mixture in at least one distillation column to form a CO-rich fluid. 2 and a means for delivering the abundant liquid.
[0008] According to another optional aspect, The apparatus includes a cycle compressor coupled to a turbine; The device is coupled to a turbine, 2 a compressor for the rich product; A portion of the gas compressed in the product compressor is liquefied and returned as reflux to at least one distillation column; The device is operated by separating CO2 The system includes a distillation column fed with a NOx-rich liquid, and a NOx removal column fed with the bottoms liquid from the distillation column.
[0009] According to another aspect of the present invention, CO 2 The gas containing CO is separated at low temperatures. 2 1. An apparatus for producing a CO-rich fluid, the apparatus comprising: a compressor including at least two stages; a first heat exchanger; a cooler; a distillation system including at least one phase separator and / or at least one distillation column; a turbine; and a CO 2 -rich fluid as compressed by the compressor. 2 and CO 2 means for sending a gas containing at least one lighter component; means for sending the compressed gas to be cooled in at least one downstream of the cooler stage; means for sending the compressed and cooled gas to be cooled in a first heat exchanger; and means for separating by partial condensation and / or distillation to obtain CO. 2 is abundant and CO 2 Fluids depleted of lighter components and CO 2 is deficient and CO 2 means for directing the gas cooled in the first heat exchanger to be heated first in the first heat exchanger and then in the cooler to produce a gas enriched in lighter components; 2 a means for transmitting the depleted gas to be expanded in a turbine; 2 and means for delivering the gas heated by the cooler.
[0010] The invention will now be explained in more detail with reference to the figures. [Brief description of the drawings]
[0011] [Figure 1] FIG. 1 illustrates a schematic representation of the process according to the invention. [Diagram 2] FIG. 2 illustrates a schematic representation of the process according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] Figure 1 shows the CO 2 1 illustrates a schematic representation of a process that uses a single distillation column to remove lighter components.
[0013] Gas stream 1 is compressed in a multi-stage compressor having, in this example, four stages C1, C2, C3, C4, with coolers R1, R2, R3 between each pair of stages and two coolers R4, R5 downstream of the last stage. 2 or CO 2 It may be a waste product from the PSA and may be compressed to at least 35 bar absolute in compressor stages C1-C4. Coolers R1-R3 are cooled solely by cooling water CW, as is cooler R5.
[0014] Gas Stream 1 is CO 2 and at least one lighter component which may be hydrogen, carbon monoxide, nitrogen or oxygen. In this example, the gas stream is rich in nitrogen. Preferably, gas stream 1 contains less than 1 mol % methane.
[0015] The gas stream cooled in the two coolers R4, R5 downstream of the last stage is cooled in a first heat exchanger E to a temperature below −50° C. by heat exchange with at least one fluid originating from a cold-hot separation. This exchanger E can be a plate-and-fin type exchanger made from brazed aluminum.
[0016] The gas stream 1 is partially condensed in a first heat exchanger E and the two-phase stream formed is separated in a phase separator S to form at least one lighter component, in this example a gas 3 rich in at least nitrogen. This gas is the only cooling fluid sent to a first cooler R4 which is heated in the first exchanger E to a temperature above the ambient temperature, for example above 30° C., and is then heated in this first cooler R4 immediately after the last stage C4 of the compressor from a temperature of 30° C. to a temperature of 100° C.
[0017] The gas cooled in the first cooler R4 is then cooled in a second cooler R5 against cooling water CW to an ambient temperature below 40°C, in practice even below 30°C.
[0018] Alternatively, the at least one light component-rich gas stream 3 can cool the compressed gas in a second cooler R5, the first cooler being water cooled.
[0019] Alternatively or additionally, at least one light component-rich stream may cool the compressed gas in a cooler R1, R2, R3 between two stages of the compressor.
[0020] Thus, the gas 3 expanded in the turbine T is preheated against the gas compressed in the compressors C1-C4, thereby enabling the heat of compression to generate more energy in the turbines.
[0021] The light component-rich gas stream 3 heated in the first cooler R4 is at 8 bar and is expanded from this pressure to near atmospheric pressure in turbine T. The light component-rich gas stream 3 can then be used to regenerate an adsorbent for drying the gas that feeds the PSA producing stream 1.
[0022] The liquid 5 from the phase separator S is expanded and then sent to the top of the stripping column, distillation column C, from which CO 2 A liquid 9, rich in CO and depleted in at least one light component, is withdrawn at the bottom. This liquid may form at least part of the product of the process. At least a part of the liquid may be pressurized in a pump P and sent for vaporization in a first heat exchanger E, and a part 11 of the vaporized liquid on reboiling is optionally sent to the bottom of column C. At least a part 13 of the vaporized liquid is compressed in a product compressor C5 driven by a turbine T to produce CO. 2 The gas is then compressed in other compression stages C6, C7, with a water cooler CW between each pair of stages (R6 between C5 and C6) and a final cooler downstream of stage C7. The gas compressed in C7 is then compressed into CO 2 The resulting gas product is rich in
[0023] The overhead gas 7 from column C is heated in the first exchanger E.
[0024] Exchanger E, phase separator S and column C are located within an insulating chamber CB.
[0025] Two means of low temperature generation are used. CO 2 is compressed in cycle compressor CC and returned through two different valves to the first heat exchanger where it is cooled, liquefied, separated and expanded forming two streams of 5.5 and 9.5 bar absolute. These two streams are heated in the first heat exchanger E to provide cold and then returned to cycle compressor CC. Vaporization of liquid 9 in exchanger E.
[0026] Obviously, the system may comprise several phase separators in series and / or parallel and upstream of the distillation, and may also comprise at least one distillation column.
[0027] If the system does not include a column separator, the turbine expanded gas is removed at the top of the distillation column.
[0028] Figure 2 shows the CO 2 The lighter components are removed and the CO 2 1 illustrates a schematic representation of a process using two columns to remove heavier components.
[0029] Gas stream 1 is compressed in a multi-stage compressor having, in this example, four stages C1, C2, C3, C4, with coolers R1, R2, R3 between each pair of stages and two coolers R4, R5 downstream of the last stage. 2 or CO 2 It may be a waste product from the PSA and may be compressed to at least 35 bar absolute in stages of compressors C1-C4. Coolers R1-R3 are cooled solely by cooling water CW, as is cooler R5.
[0030] Gas Stream 1 is CO 2and at least one lighter component which may be hydrogen, carbon monoxide, nitrogen or oxygen. In this example, the gas stream is rich in nitrogen. Preferably, gas stream 1 contains less than 1 mol % methane.
[0031] The gas stream cooled in the two coolers R4, R5 downstream of the last stage is cooled in a first heat exchanger E to a temperature below −50° C. by heat exchange with at least one fluid originating from the cryogenic separation. This exchanger E can be a plate-and-fin type exchanger made from brazed aluminium.
[0032] The gas stream 1 is partially condensed in a first heat exchanger E and the two-phase stream formed is separated in a phase separator S to form at least one lighter component, in this example a gas 3 rich in at least nitrogen. This gas is the only cooling fluid sent to a first cooler R4 which is heated in the first exchanger E to a temperature above the ambient temperature, for example above 30° C., and is then heated in this first cooler R4 immediately after the last stage C4 of the compressor from a temperature of 30° C. to a temperature of 100° C.
[0033] The gas cooled in the first cooler R4 is then cooled in a second cooler R5 against cooling water CW to an ambient temperature below 40°C, in practice even below 30°C.
[0034] Alternatively, the at least one light component-rich gas stream 3 can cool the compressed gas in a second cooler R5, the first cooler being water cooled.
[0035] Alternatively or additionally, at least one light component-rich stream may cool the compressed gas in a cooler R1, R2, R3 between two stages of the compressor.
[0036] Thus, the gas 3 expanded in the turbine T is preheated against the gas compressed in the compressors C1-C4, thereby enabling the heat of compression to generate more energy in the turbines.
[0037] The light-rich gas stream 3, heated in the first cooler R4, is at 8 bar and is expanded in a turbine T from this pressure to approximately atmospheric pressure. The light-rich gas stream 3 can then be used to regenerate an adsorbent for drying the gas that feeds the PSA producing stream 1. Additionally or alternatively, the expanded stream 3 is cooled to room temperature to remove CO2 that it contains. 2 The resulting mixture can be fed to a PSA unit for recovery.
[0038] The liquid 5 from the phase separator S is expanded and then sent to the top of the distillation column C, from which CO 2 A liquid 9 rich in and depleted in at least one light component is withdrawn at the bottom. At least a part of the liquid can be pressurized with a pump P and sent to be vaporized in a first heat exchanger E, a part 11 of the liquid vaporized on reboiling is optionally sent to the bottom of the column C, and another part 19 is sent to feed the column N at the bottom. The overhead gas 7 from the column C is heated in the first exchanger E.
[0039] Tower N is CO 2 A tower for removing the heavier NOx compounds, which are the following compounds: nitric oxide (NO), nitrogen dioxide (NO 2 ), nitrous oxide (N 2 O), dinitrogen tetroxide (N 2 O 4 ) and dinitrogen trioxide (N 2 O 3 ) is the name applied to CO 2 Because it is lighter, tower N is more effective at reducing nitrogen dioxide (NO 2 ), nitrous oxide (N 2 O), dinitrogen tetroxide (N 2 O 4 ) and dinitrogen trioxide (N 2 O 3 ) is used to remove
[0040] In this column, fed by stream 19, CO 2 At least one of the heavier impurities is CO 2 15 intermediate reflux and pure CO 2and NOx compounds, e.g., NO 2 At the bottom, a liquid 25 enriched in at least one heavier impurity such as
[0041] The liquid 25 rich in at least one heavier impurity is vaporized in a first exchanger E.
[0042] The overhead gas 21 from column N constitutes the product purified of at least one heavier impurity and is heated in a first exchanger E before being compressed in a first compression stage C5 driven by a turbine T. After cooling in R6, the stream is split, a portion 23 is condensed in the first exchanger E and the remaining portion 27 is compressed in compression stages C6, C7 to form a compressed gas product. The gas compressed in C7 is the CO2 product of this example. 2 The resulting gas product is rich in
[0043] Portion 23 is returned at the top of column N as reflux.
[0044] Exchanger E, phase separator S and column C are located within an insulating chamber CB.
[0045] Two means of low temperature generation are used. CO 2 is compressed in cycle compressor CC and returned through two different valves to the first heat exchanger where it is cooled, liquefied, separated and expanded forming two streams of 5.5 and 9.5 bar absolute. These two streams are heated in the first heat exchanger E to provide cold and then returned to cycle compressor CC. Vaporization of liquid 9 in exchanger E.
[0046] Obviously, the system may comprise several phase separators in series and / or parallel and upstream of the distillation, and may also comprise at least one distillation column.
[0047] If the system does not include a column separator, the turbine expanded gas is removed at the top of the distillation column.
[0048] Preferably, at least one of the cycle compressors CC and at least one of the product compressors C6, C7 are combined into a single compressor.
[0049] The turbine may drive at least one refrigeration cycle compressor, for example CC, and / or at least one other product compressor C6, C7 in addition to or instead of compressor C5.
Claims
1. CO ２ The gas containing CO is separated at a low temperature. ２ A process for producing a CO rich fluid comprising: ２ and CO ２ A gas containing at least one lighter component is compressed in a compressor (C1, C2, C3, C4) comprising at least two stages, said gas is first cooled in a cooler (R4, R5) downstream of the last of said stages and then cooled to ambient temperature by heat exchange with water (CW) or vice versa and then cooled in a first heat exchanger (E), said gas cooled in said first heat exchanger being separated at low temperature by partial condensation to obtain CO ２ is rich in CO ２ A liquid (5) depleted of the lighter components (9, 21) and CO ２ is deficient and CO ２ and a gas (3) rich in the lighter components, ２ The gas depleted in CO is heated first in the first heat exchanger and then in the cooler before being expanded in a turbine (T) and ２ The CO2-rich liquid is separated by distillation to obtain at least one CO ２ A process for forming a fluid (8, 9, 21) rich in
2. The at least one CO ２ The CO rich fluid is liquid (9), and ２ 2. The process according to claim 1, wherein at least a portion of the rich fluid is vaporized in the first heat exchanger (E).
3. The at least one vaporized CO ２ 3. The process according to claim 2, wherein the rich fluid is compressed in a compressor (C5) driven by said turbine (T).
4. The CO ２ The liquid rich in CO is expanded and sent to the top of a stripping column (C) and the at least one CO ２ 4. The process according to claim 2 or 3, wherein the rich fluid is the bottoms (8, 9) from the strip column.
5. The CO ２ The process according to any one of claims 1 to 4, wherein the rich liquid (5) is sent to the top of a wash column and the liquid from the wash column is fed to a distillation column.
6. 6. The process according to claim 5, wherein the top gas (21) from the distillation column (C) is compressed in a compressor (C5) driven by the turbine (T).
7. The CO ２ The process according to any one of claims 1 to 6, wherein the depleted gas enters the cooler (R4) at a temperature higher than ambient temperature, for example higher than 30°C.
8. The separated gas is separated by partial condensation (S) to form the CO ２ The resulting mixture is then cooled to room temperature to produce a depleted gas (3) and also a liquid (5), which is separated by distillation in a distillation column, preferably from CO ２ The CO ２ The process according to any one of claims 1 to 7, wherein said process produces a fluid (9, 21) enriched in
9. The process according to any one of claims 1 to 8, wherein at least a part of the cold is provided by a closed refrigeration cycle including at least one cycle compressor driven by said turbine (T).
10. The at least one CO ２ The process according to any one of claims 1 to 9, wherein the rich fluid is a gas (21) which is heated in the first heat exchanger (E) before being compressed.
11. CO ２ The gas containing CO is separated at a low temperature. ２ The apparatus for producing a fluid rich in CO comprises a compressor (C1, C2, C3, C4) including at least two stages, a cooler (R4, R5), a water cooler, a first heat exchanger (E), a phase separator, a turbine (T) and at least one distillation column, and a CO ２ and CO ２ means for sending gas containing at least one lighter component to said compressor (C1, C2, C3, C4) which comprises at least two stages; means for sending said compressed gas from said compressor to be cooled in said cooler (R4) and said water cooler (CW); means for sending said gas cooled in said cooler and said water cooler to said first heat exchanger (E); ２ is rich in CO ２ Liquids depleted of the lighter components (9, 21) and CO ２ is deficient and CO ２ means for sending the gas cooled in the first heat exchanger to the phase separator to form a gas enriched in the lighter components (3); and means for sending the gas cooled in the first heat exchanger to the phase separator to be heated first in the first heat exchanger and then in the cooler. ２ means for sending said CO2 depleted gas heated by said cooler to be expanded in said turbine; ２ means for delivering the depleted gas; and at least one CO ２ to be separated in the at least one distillation column to form a CO ２ and means for delivering the abundant liquid.
12. The apparatus of claim 11, further comprising a cycle compressor (CC) coupled to the turbine (T).
13. A CO ２ 12. The apparatus according to claim 11, further comprising a compressor (C5) for the rich product.
14. 14. The apparatus according to claim 13, wherein a portion (23) of the gas compressed in the product compressor (C5) is liquefied and returned as reflux to the at least one distillation column (C).
15. The CO coming from the phase separator ２ 15. The apparatus according to claim 11, further comprising a distillation column fed with a NOx-rich liquid (5) and a NOx removal column (N) fed with bottoms from said distillation column.