Low-temperature methanol washing pre-separation device
By introducing a CO2 membrane separation unit into the low-temperature methanol washing process, the problem of excessive equipment load was solved, achieving efficient use of methanol solution and stable equipment operation, and reducing operating costs.
Patent Information
- Application Number
- CN202423143238.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2034-12-19
AI Technical Summary
The existing low-temperature methanol washing process requires a large amount of methanol and refrigeration energy during operation, resulting in high operating costs and a tendency for efficiency decline and failure.
By adding a CO2 membrane separation unit, combined with a water separator, a low-temperature methanol washing tower, and a methanol regeneration tower, CO2 can be selectively separated using the CO2 membrane separation components, thereby reducing methanol consumption and refrigeration energy consumption and improving purification efficiency.
It effectively reduced the processing load of the low-temperature methanol washing unit, extended the service life of the methanol solution, improved gas purification efficiency, and reduced the operating pressure of the equipment.
Smart Images
Figure CN223646514U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of low-temperature methanol washing pre-separation technology, specifically to a device for low-temperature methanol washing pre-separation. Background Technology
[0002] Existing low-temperature methanol washing processes are widely used in natural gas purification and syngas treatment to remove acidic gases such as carbon dioxide (CO2) and hydrogen sulfide (H2S).
[0003] However, this process requires a large amount of methanol and refrigeration energy during operation, and the methanol solution needs to be regenerated frequently, resulting in high equipment operating costs and a large system load. In addition, methanol washing equipment is prone to efficiency decline and failure under heavy load.
[0004] Based on this, a low-temperature methanol washing and pre-separation device is now provided, which can eliminate the drawbacks of existing devices. Utility Model Content
[0005] To address the aforementioned issues, a low-temperature methanol washing pre-separation device is provided. By adding a CO2 membrane separation unit, the problem of reduced efficiency and malfunctions in methanol washing equipment under heavy load is solved.
[0006] To address the problems in the existing technology, this utility model provides a low-temperature methanol washing pre-separation device, including a dehydrator. The dehydrator has a first syngas inlet and a first methanol inlet on its side wall. The upper end of the dehydrator has a second syngas inlet, and the lower end of the dehydrator has a first methanol outlet. The other end of the second syngas inlet is connected to a CO2 membrane separation component. The upper end of the side wall of the CO2 membrane separation component has a CO2 outlet, and the lower end of the side wall of the CO2 membrane separation component has a third syngas inlet. The other end of the third syngas inlet is connected to a low-temperature methanol washing tower.
[0007] Preferably, the low-temperature methanol washing tower is provided with a third methanol inlet, the upper end of the low-temperature methanol washing tower is provided with a third syngas outlet, the lower end of the low-temperature methanol washing tower is provided with a fourth methanol inlet, and the other end of the fourth methanol inlet is connected to a methanol regeneration tower.
[0008] Preferably, the methanol regeneration tower has an acid gas outlet at the upper end and a fourth methanol outlet at the lower end.
[0009] Preferably, the other end of the third methanol inlet is connected to a cooler, and the cooler is provided with a second methanol inlet.
[0010] Preferably, the CO2 membrane separation component is made of a permeable acidic gas transport-promoting membrane or a proton-type ionic liquid membrane, or a combination of both.
[0011] The advantages of this utility model compared to the prior art are:
[0012] 1. This utility model effectively reduces the processing load of the low-temperature methanol washing unit and extends the service life of the methanol solution through the CO2 membrane separation unit.
[0013] 2. This utility model improves gas purification efficiency and reduces equipment operating pressure through synergistic membrane separation and methanol washing processes. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of a low-temperature methanol washing and pre-separation device.
[0015] The diagram is labeled as follows: 1. First syngas inlet; 2. Dehydrator; 3. First methanol inlet; 4. First methanol outlet; 5. Second syngas inlet; 6. CO2 membrane separation unit; 7. Third syngas inlet; 8. CO2 outlet; 9. Low-temperature methanol scrubbing tower; 10. Second methanol inlet; 11. Third methanol inlet; 12. Third syngas outlet; 13. Fourth methanol inlet; 14. Methanol regeneration tower; 15. Fourth methanol outlet; 16. Acid gas outlet; 17. Cooler. Detailed Implementation
[0016] To further understand the features, technical means, and specific objectives and functions achieved by this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments.
[0017] Reference Figure 1 A low-temperature methanol washing and pre-separation device includes a dehydrator 2, a first syngas inlet 1 and a first methanol inlet 3 on the side wall of the dehydrator 2, a second syngas inlet 5 at the upper end of the dehydrator 2, a first methanol outlet 4 at the lower end of the dehydrator 2, the other end of the second syngas inlet 5 being connected to a CO2 membrane separation component 6, a CO2 outlet 8 at the upper end of the side wall of the CO2 membrane separation component 6, a third syngas inlet 7 at the lower end of the side wall of the CO2 membrane separation component 6, and the other end of the third syngas inlet 7 being connected to a low-temperature methanol washing tower 9.
[0018] Syngas enters the dehydrator 2 through the first syngas inlet 1, and methanol is sprayed through the first methanol inlet 3 to remove moisture from the syngas. The sprayed methanol carrying water is discharged from the first methanol outlet 4. CO2 is selectively separated by a membrane and discharged from the CO2 outlet 8. The remaining gas enters the low-temperature methanol scrubbing tower 9 through the third syngas inlet 7.
[0019] Reference Figure 1The low-temperature methanol washing tower 9 is provided with a third methanol inlet 11, a third syngas outlet 12 at the upper end of the low-temperature methanol washing tower 9, and a fourth methanol inlet 13 at the lower end of the low-temperature methanol washing tower 9. The other end of the fourth methanol inlet 13 is connected to the methanol regeneration tower 14.
[0020] The third methanol inlet 11 is used to introduce methanol to further remove residual CO2 and H2S from the synthesis gas; the purified synthesis gas is discharged from the third synthesis gas outlet 12, and the methanol solution containing CO2 and H2S flows out from the bottom of the tower and enters the methanol regeneration tower 14 through the fourth methanol inlet 13.
[0021] Reference Figure 1 The methanol regeneration tower 14 is provided with an acid gas outlet 16 at the upper end and a fourth methanol outlet 15 at the lower end.
[0022] Methanol regeneration tower 14 is used to regenerate methanol. CO2 and H2S acidic gases are discharged from the acidic gas outlet 16 at the top of the tower, and the regenerated methanol flows out from the fourth methanol outlet 15 at the bottom of the tower.
[0023] Reference Figure 1 The other end of the third methanol inlet 11 is connected to the cooler 17, and the cooler 17 is provided with a second methanol inlet 10.
[0024] The regenerated methanol is combined with the fresh methanol introduced from the second methanol inlet 10 and cooled to -40°C to -50°C by the cooler 17. The cooled methanol is used for the purification of syngas in the low-temperature methanol washing tower 9. The syngas contains a small amount of water, which is removed after being treated by the dehydrator 2. Subsequently, some CO2 is separated in the CO2 membrane separation component 6, reducing the load on the low-temperature methanol washing tower 9. The dehydrator 2 removes water from the syngas by spraying methanol, and the methanol carrying the water is discharged from the first methanol outlet 4.
[0025] Reference Figure 1 The CO2 membrane separation component 6 is made of a permeable acidic gas transport-promoting membrane or a proton-type ionic liquid membrane, or a combination of both.
[0026] The CO2 membrane separation unit 6 uses a selectively permeable acidic gas-promoting transport membrane, a proton-type ionic liquid membrane, or a combination of both. This can effectively reduce methanol consumption and refrigeration energy consumption, and improve separation efficiency and system stability.
[0027] Working principle:
[0028] S1. Synthesis gas containing a small amount of moisture is introduced into the dehydrator 2 through the first synthesis gas inlet 1. Simultaneously, methanol is sprayed from the first methanol inlet 3 to remove moisture from the synthesis gas. The sprayed methanol, carrying moisture, flows out from the first methanol outlet 4. The moisture-removed synthesis gas is then introduced into the CO2 membrane separation unit 6 through the second synthesis gas inlet 5. The membrane separation unit selectively absorbs CO2, which flows out from the CO2 outlet 8. The remaining gas is introduced into the low-temperature methanol scrubbing tower 9 through the third synthesis gas inlet 7. Simultaneously, methanol is introduced from the third methanol inlet 11 to further remove residual CO2 and H2S from the synthesis gas. The methanol solution containing CO2 and H2S flows out from the bottom of the tower. The methanol flows into the methanol regeneration tower 14 from the fourth methanol inlet 13. After passing through the methanol regeneration tower, CO2 and H2S acidic gases flow out from the acidic gas outlet 16 at the top of the tower. The regenerated methanol flows out from the fourth methanol outlet 15 at the bottom of the tower and merges with the second methanol inlet 10. After passing through the cooler 17, it is cooled to a low temperature of -40 to -50°C. The remaining purified synthesis gas flows out from the third synthesis gas outlet 12. Fresh methanol is introduced into the second methanol inlet 10. The synthesis gas containing a small amount of moisture enters the dehydrator 2 from the first synthesis gas inlet 1. The main function of the dehydrator is to remove moisture from the synthesis gas by spraying methanol to prevent moisture from affecting the separation effect and equipment operation in subsequent processing.
[0029] S2. Then, a portion of methanol is introduced from the first methanol inlet 3 and fully contacts the synthesis gas through spraying. The methanol absorbs the moisture in the synthesis gas. After dehydration treatment, the methanol solution carrying the absorbed moisture is discharged from the first methanol outlet 4.
[0030] S3. The syngas, after the moisture has been removed, enters the CO2 membrane separation module 6 from the second syngas inlet 5. The function of the CO2 membrane separation module is to preferentially separate CO2 from the syngas through the selective permeability of the membrane material.
[0031] S4. In the CO2 membrane separation module, CO2 gas is selectively separated and discharged from CO2 outlet 8. The separated CO2 can be recovered or otherwise treated, and the remaining syngas enters the next processing stage through the third syngas inlet 7.
[0032] S5. Syngas with some CO2 separated enters low-temperature methanol washing tower 9. The main function of this tower is to further remove residual CO2 and acidic gases such as H2S from the syngas.
[0033] S6. Low-temperature methanol is introduced from the third methanol inlet 11 to further absorb residual CO2 and H2S in the synthesis gas. In this step, the low-temperature characteristics of methanol enable it to efficiently absorb acidic gases. The purified synthesis gas is discharged from the third synthesis gas outlet 12 and used as the final purified synthesis gas for downstream chemical synthesis processes.
[0034] S7. The methanol solution that has absorbed acidic gases such as CO2 and H2S flows out from the bottom of the low-temperature methanol washing tower and then enters the methanol regeneration tower 14 through the fourth methanol inlet 13.
[0035] S8. Inside the methanol regeneration tower, the methanol solution undergoes a regeneration process such as heating. Acidic gases CO2 and H2S are discharged from the acidic gas outlet 16 at the top of the tower, while the separated methanol solution flows out from the fourth methanol outlet 15 at the bottom of the tower.
[0036] S9. The regenerated methanol is combined with the fresh methanol introduced from the second methanol inlet 10 and cooled to a low temperature of -40°C to -50°C by the cooler 17. The cooled methanol is reused for synthesis gas purification in the low temperature methanol washing tower to form a circulating methanol washing system.
[0037] S10. After being processed by the low-temperature methanol washing tower, impurities such as CO2 and H2S in the syngas have been effectively removed. The remaining purified syngas is discharged from the third syngas outlet 12, resulting in high-purity syngas that meets the process requirements.
[0038] The above embodiments only illustrate one or more implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.
Claims
1. A device for low-temperature methanol washing and pre-separation, characterized in that, The device includes a dewatering device (2), which has a first syngas inlet (1) and a first methanol inlet (3) on its side wall. The dewatering device (2) has a second syngas inlet (5) at its upper end and a first methanol outlet (4) at its lower end. The other end of the second syngas inlet (5) is connected to a CO2 membrane separation unit (6). The CO2 membrane separation unit (6) has a CO2 outlet (8) at its upper side wall and a third syngas inlet (7) at its lower side wall. The other end of the third syngas inlet (7) is connected to a low-temperature methanol washing tower (9).
2. The apparatus for low-temperature methanol washing and pre-separation according to claim 1, characterized in that, The low-temperature methanol washing tower (9) is provided with a third methanol inlet (11), the upper end of the low-temperature methanol washing tower (9) is provided with a third syngas outlet (12), the lower end of the low-temperature methanol washing tower (9) is provided with a fourth methanol inlet (13), and the other end of the fourth methanol inlet (13) is connected to the methanol regeneration tower (14).
3. The apparatus for low-temperature methanol washing and pre-separation according to claim 2, characterized in that, The methanol regeneration tower (14) is provided with an acid gas outlet (16) at the upper end and a fourth methanol outlet (15) at the lower end.
4. The apparatus for low-temperature methanol washing and pre-separation according to claim 2, characterized in that, The other end of the third methanol inlet (11) is connected to a cooler (17), and the cooler (17) is provided with a second methanol inlet (10).
5. The apparatus for low-temperature methanol washing and pre-separation according to claim 1, characterized in that, The CO2 membrane separation component (6) is made of a permeable acidic gas transport membrane or a proton-type ionic liquid membrane or a combination of both.