Amine liquid regeneration system and method based on activated carbon in-situ purification
By introducing an activated carbon adsorption unit into the amine liquid regeneration system, the problem of amine liquid degradation was solved, achieving efficient purification and long-term stable operation of the amine liquid, and reducing operating costs and corrosion risks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-20
- Publication Date
- 2026-04-14
AI Technical Summary
In existing amine-based carbon capture processes, the amine solution reacts with oxygen, sulfur oxides, and nitrogen oxides during operation to produce degradation products, which leads to decreased absorption efficiency, increased system corrosion, and increased energy consumption. Existing purification methods are costly, complex to operate, and difficult to achieve long-term stable operation.
An in-situ activated carbon purification system is adopted, integrating the activated carbon adsorption unit into the amine liquid regeneration system. The activated carbon adsorption removes degradation products and thermally stable salts from the amine liquid, including separate treatment of rich and lean liquids. Steam purging is used to regenerate saturated carbon, achieving continuous or intermittent purification.
It effectively extends the service life of amine solution, reduces system corrosion and energy consumption, maintains high collection efficiency, reduces amine solution consumption and operating costs, and is easy to operate and highly integrated.
Smart Images
Figure CN121846850A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flue gas carbon dioxide capture technology, and in particular to a system and method for in-situ purification of amine solution using activated carbon in an amine chemical absorption carbon capture process to maintain the system's efficient and stable operation. Background Technology
[0002] Amine chemical absorption is currently the most mature large-scale flue gas carbon dioxide capture technology; however, during operation, the absorbent amine liquid will undergo irreversible reactions with oxygen, sulfur oxides (SOx), nitrogen oxides (NOx) in the flue gas, resulting in chemical degradation and the generation of thermally stable salts (HSS) and other organic acids and other degradation products. These degradation products will lead to a decrease in the absorption efficiency of the amine liquid, foaming, increased system corrosion, and increased energy consumption.
[0003] In existing amine-based carbon capture processes, the treatment of amine degradation products mainly relies on periodic discharge replacement or the addition of independent purification devices such as ion exchange and electrodialysis. The former results in high amine consumption, high operating costs, and secondary pollution; the latter has problems such as large equipment investment, complex operation, high energy consumption, and the generation of waste liquid or waste resin that needs to be treated, making it difficult to achieve long-term stable operation of amine solutions in an economical and efficient manner.
[0004] Therefore, it is necessary to develop an amine liquid purification method that is highly integrated, low-cost, and easy to operate, in order to extend the life of the amine liquid, reduce operating costs, and ensure the long-term stable operation of the carbon capture system. Summary of the Invention
[0005] The purpose of this invention is to solve the problems in the prior art and propose an amine liquid regeneration system and method based on in-situ purification with activated carbon. This system is highly integrated, low-cost, and easy to operate, and can continuously or intermittently remove degradation products and heat-stable salts from amine liquid, thereby significantly extending the service life of amine liquid, reducing system corrosion, and maintaining high collection efficiency.
[0006] To achieve the above objectives, this invention proposes an amine regeneration system based on in-situ activated carbon purification, comprising a reboiler and, in sequence, an absorption tower, a phase separation tank, a rich liquid buffer tank, the rich liquid side of a rich-lean liquid heat exchanger, a regeneration tower, a flash tank, the lean liquid side of a rich-lean liquid heat exchanger, and a mixing tank, forming a circulation path. The reboiler is connected to the regeneration tower. The system is characterized by further including at least one activated carbon adsorption unit, the inlet of which is connected to the amine regeneration pipeline, and the outlet of which is connected back to the amine regeneration pipeline.
[0007] Preferably, the number of activated carbon adsorption units is two, namely a rich-liquid activated carbon adsorption unit and a lean-liquid activated carbon adsorption unit.
[0008] Preferably, the rich-liquid activated carbon adsorption unit includes two activated carbon adsorption towers I, a rich-liquid inlet pipe, a purified rich-liquid outlet pipe, and several valves I. Two activated carbon adsorption towers I are connected in parallel between the rich-liquid inlet pipe and the purified rich-liquid outlet pipe. Each of the connection ports of the activated carbon adsorption towers I with the rich-liquid inlet pipe and the purified rich-liquid outlet pipe is equipped with a valve I.
[0009] Preferably, the rich liquid buffer tank is equipped with a rich liquid diversion valve connected thereto, and the two output ends of the rich liquid diversion valve are respectively connected to the amine liquid circulation pipeline at the rich liquid inlet pipe and the rich liquid inlet of the lean-rich liquid heat exchanger.
[0010] Preferably, the lean liquor activated carbon adsorption unit includes two activated carbon adsorption towers II, a lean liquor inlet pipe, a purified lean liquor outlet pipe, and several valves II. Two activated carbon adsorption towers II are connected in parallel between the lean liquor inlet pipe and the purified lean liquor outlet pipe. Each of the connection ports of the activated carbon adsorption towers II with the lean liquor inlet pipe and the purified lean liquor outlet pipe is equipped with a valve II.
[0011] Preferably, the mixing tank is equipped with a lean liquid diversion valve connected thereto, and the two output ends of the lean liquid diversion valve are respectively connected to the lean liquid inlet pipe and the amine liquid circulation pipeline of the lean liquid inlet of the absorption tower.
[0012] Preferably, the activated carbon adsorption unit is filled with granular activated carbon with a specific surface area greater than 800 m² / g.
[0013] An amine regeneration method using the above-described amine regeneration system based on in-situ activated carbon purification includes the following steps: S1: At least one stream of amine solution is diverted from the amine solution circulation pipeline; S2: The diverted amine solution flows through the activated carbon adsorption unit, where degradation products and thermally stable salts in the amine solution are adsorbed and removed by the activated carbon. S3: The purified amine solution is returned to the amine solution circulation pipeline; S4: When the activated carbon is saturated, switch to the parallel standby adsorption unit and regenerate or replace the saturated activated carbon.
[0014] Preferably, when the amine solution diverted in step S1 is a single stream, it is either a rich amine solution or a lean amine solution; when the amine solution diverted in two streams, it is a rich amine solution and a lean amine solution, respectively. In step S2, the rich amine solution and the lean amine solution diverted flow through the rich amine solution activated carbon adsorption unit and the lean amine solution activated carbon adsorption unit, respectively.
[0015] Preferably, the regeneration in step S4 is performed by steam purging.
[0016] The beneficial effects of this invention are as follows: By integrating an activated carbon adsorption bed into an amine regeneration system, this invention purifies lean amine solution and / or rich amine solution in situ, continuously or intermittently, thereby effectively removing degradation products and heat-stable salts from the amine solution and extending the service life of the amine solution.
[0017] Activated carbon adsorption beds can efficiently and selectively remove chemical degradation products such as heat-stable salts, organic acids, and physical impurities such as foaming precursors and suspended solids accumulated in amine solutions.
[0018] Employing activated carbon materials with abundant pore structure and cost-controllable regeneration technology, it can be directly embedded into existing processes, achieving high integration and maintaining the optimal absorption performance of amine solutions.
[0019] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structure of an amine liquid regeneration system based on in-situ purification with activated carbon according to the present invention.
[0021] In the diagram: 1-Reboiler, 2-Absorber, 3-Phase Separator, 4-Rich Solution Buffer Tank, 5-Rich / Lean Solution Heat Exchanger, 6-Regeneration Tower, 7-Flash Tank, 8-Mixing Tank, 10-Activated Carbon Adsorption Tower I, 11-Rich Solution Inlet Pipe, 12-Purified Rich Solution Outlet Pipe, 13-Valve I, 14-Rich Solution Diversion Valve, 20-Activated Carbon Adsorption Tower II, 21-Lean Solution Inlet Pipe, 22-Purified Lean Solution Outlet Pipe, 23-Valve II, 24-Lean Solution Diversion Valve. Detailed Implementation
[0022] See Figure 1 The present invention discloses an amine regeneration system based on in-situ purification with activated carbon, comprising a reboiler 1 and an absorption tower 2, a phase separation tank 3, a rich liquid buffer tank 4, a rich liquid side of a lean-rich liquid heat exchanger 5, a regeneration tower 6, a flash tank 7, a lean liquid side of the lean-rich liquid heat exchanger 5, and a mixing tank 8 connected in sequence through an amine circulation pipeline, forming a circulation path. The reboiler 1 is connected to the regeneration tower 6. The invention is characterized by further including at least one activated carbon adsorption unit, the inlet of which is connected to the amine circulation pipeline, and the outlet of which is connected back to the amine circulation pipeline.
[0023] The number of activated carbon adsorption units is two, namely a rich-liquid activated carbon adsorption unit and a lean-liquid activated carbon adsorption unit.
[0024] The rich-liquid activated carbon adsorption unit includes two activated carbon adsorption towers I10, a rich-liquid inlet pipe 11, a purified rich-liquid outlet pipe 12, and several valves I13. Two activated carbon adsorption towers I10 are connected in parallel between the rich-liquid inlet pipe 11 and the purified rich-liquid outlet pipe 12. Each of the connection ports of the activated carbon adsorption towers I10 with the rich-liquid inlet pipe 11 and the purified rich-liquid outlet pipe 12 is equipped with a valve I13.
[0025] The rich liquid buffer tank 4 is equipped with a rich liquid diversion valve 14 connected to it. The two output ends of the rich liquid diversion valve 14 are respectively connected to the amine liquid circulation pipeline of the rich liquid inlet pipe 11 and the rich liquid inlet of the lean and rich liquid heat exchanger 5.
[0026] The lean liquor activated carbon adsorption unit includes two activated carbon adsorption towers II20, a lean liquor inlet pipe 21, a purified lean liquor outlet pipe 22, and several valves II23. Two activated carbon adsorption towers II20 are connected in parallel between the lean liquor inlet pipe 21 and the purified lean liquor outlet pipe 22. Each activated carbon adsorption tower II20 is equipped with a valve II23 at the connection port between it and the lean liquor inlet pipe 21 and the purified lean liquor outlet pipe 22.
[0027] The mixing tank 8 is equipped with a lean liquid diversion valve 24 connected to it. The two output ends of the lean liquid diversion valve 24 are respectively connected to the lean liquid inlet pipe 21 and the amine liquid circulation pipeline of the lean liquid inlet of the absorption tower 2.
[0028] The activated carbon adsorption unit is filled with granular activated carbon, which has a specific surface area greater than 800 m² / g.
[0029] An amine regeneration method using the above-described amine regeneration system based on in-situ activated carbon purification includes the following steps: S1: At least one stream of amine solution is diverted from the amine solution circulation pipeline; S2: The diverted amine solution flows through the activated carbon adsorption unit, where degradation products and thermally stable salts in the amine solution are adsorbed and removed by the activated carbon. S3: The purified amine solution is returned to the amine solution circulation pipeline; S4: When the activated carbon is saturated, switch to the parallel standby adsorption unit and regenerate or replace the saturated activated carbon.
[0030] Preferably, when the amine solution diverted in step S1 is a single stream, it is either a rich amine solution or a lean amine solution; when the amine solution diverted in two streams, it is a rich amine solution and a lean amine solution, respectively. In step S2, the rich amine solution and the lean amine solution diverted flow through the rich amine solution activated carbon adsorption unit and the lean amine solution activated carbon adsorption unit, respectively.
[0031] Preferably, the regeneration in step S4 is performed by steam purging.
[0032] Example 1: Treatment of low-quality fluid only A lean amine solution outflow pipeline at the bottom of the regeneration tower (located after the lean and rich solution heat exchanger) is connected in parallel with a lean amine solution activated carbon adsorption unit. This lean amine solution activated carbon adsorption unit is switchable. When the bed of one of the activated carbon adsorption towers II20 is saturated, it can be switched to the standby activated carbon adsorption tower II20 through the opening and closing of the corresponding valve II23. The saturated bed of activated carbon adsorption tower II20 is then sent externally for thermal regeneration. Coal-based briquetted activated carbon with an iodine value ≥1000 mg / g and a carbon tetrachloride adsorption value ≥60% is used to continuously treat 10% of the total circulating amine solution. The results of testing a 30% MEA solution after 72 hours of continuous operation are as follows:
[0033]
[0034] Example 2: Treatment of rich solution only Install a rich-liquid activated carbon adsorption unit on the rich-amine liquid outflow line at the bottom of the absorption tower (before entering the rich-lean liquid heat exchanger). This location can remove contaminants that cause scaling and foaming in the regeneration tower in advance.
[0035] Activated carbon specifications: Coconut shell-based activated carbon with an iodine value ≥1100 mg / g, high strength, and low powder content was used. The system was operated intermittently for 8 hours daily. A PZ (piperazine)-promoted MDEA (methyldiethanolamine) solution was tested after 72 hours of operation. The results are as follows:
[0036]
[0037] Example 3: Simultaneous treatment of amine solution and rich solution A dual-bed adsorption system was adopted, with one bed located in the lean amine liquid pipeline as in Example 1 and the other in the rich amine liquid pipeline as in Example 2. The two adsorption beds used different activated carbon formulations: the rich amine liquid pipeline focused on adsorbing macromolecular polymers and foaming agents; the lean amine liquid pipeline focused on adsorbing thermally stable salts and small molecule acids. The lean amine liquid adsorption bed was operated continuously, while the rich amine liquid adsorption bed was operated intermittently. This is a long-term operation case study for 3 months. The system is a composite amine liquid used in a large steel plant.
[0038]
[0039] This invention can be flexibly configured in lean amine liquid pipelines, rich amine liquid pipelines, or a combination of both, according to actual needs and budget, and can produce significant benefits. Regardless of the configuration, this invention can effectively reduce key pollutants in amine liquid, such as heat-stable salts and degradation products, thereby bringing a series of positive chain effects such as reducing amine liquid replenishment, reducing energy consumption, and inhibiting corrosion and foaming.
[0040] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.
Claims
1. An amine regeneration system based on in-situ purification with activated carbon, comprising a reboiler (1) and, in sequence, an absorption tower (2), a phase separation tank (3), a rich liquid buffer tank (4), the rich liquid side of a lean-rich liquid heat exchanger (5), a regeneration tower (6), a flash tank (7), the lean liquid side of the lean-rich liquid heat exchanger (5), and a mixing tank (8) connected by an amine circulation pipeline, forming a circulation path, wherein the reboiler (1) is connected to the regeneration tower (6), characterized in that: It also includes at least one activated carbon adsorption unit, the inlet of which is connected to the amine liquid circulation pipeline and the outlet is connected back to the amine liquid circulation pipeline.
2. The amine liquid regeneration system based on in-situ activated carbon purification as described in claim 1, characterized in that: The number of activated carbon adsorption units is two, namely a rich-liquid activated carbon adsorption unit and a lean-liquid activated carbon adsorption unit.
3. The amine liquid regeneration system based on in-situ activated carbon purification as described in claim 2, characterized in that: The rich liquid activated carbon adsorption unit includes two activated carbon adsorption towers I (10), a rich liquid inlet pipe (11), a purified rich liquid outlet pipe (12), and several valves I (13). Two activated carbon adsorption towers I (10) are connected in parallel between the rich liquid inlet pipe (11) and the purified rich liquid outlet pipe (12). Each of the connection ports of the activated carbon adsorption towers I (10) with the rich liquid inlet pipe (11) and the purified rich liquid outlet pipe (12) is equipped with a valve I (13).
4. The amine liquid regeneration system based on in-situ activated carbon purification as described in claim 3, characterized in that: The rich liquid buffer tank (4) is equipped with a rich liquid diversion valve (14) connected to it. The two output ends of the rich liquid diversion valve (14) are respectively connected to the amine liquid circulation pipeline of the rich liquid inlet pipe (11) and the rich liquid inlet of the lean and rich liquid heat exchanger (5).
5. The amine liquid regeneration system based on in-situ activated carbon purification as described in claim 2, characterized in that: The lean liquid activated carbon adsorption unit includes two activated carbon adsorption towers II (20), a lean liquid inlet pipe (21), a purified lean liquid outlet pipe (22), and several valves II (23). Two activated carbon adsorption towers II (20) are connected in parallel between the lean liquid inlet pipe (21) and the purified lean liquid outlet pipe (22). Each activated carbon adsorption tower II (20) is equipped with a valve II (23) at the connection port between it and the lean liquid inlet pipe (21) and the purified lean liquid outlet pipe (22).
6. The amine liquid regeneration system based on in-situ activated carbon purification as described in claim 5, characterized in that: The mixing tank (8) is equipped with a lean liquid diversion valve (24) connected to it. The two output ends of the lean liquid diversion valve (24) are respectively connected to the lean liquid inlet pipe (21) and the amine liquid circulation pipeline of the lean liquid inlet of the absorption tower (2).
7. The amine regeneration system based on in-situ activated carbon purification as described in claim 1, characterized in that: The activated carbon adsorption unit is filled with granular activated carbon, which has a specific surface area greater than 800 m² / g.
8. An amine regeneration method using an amine regeneration system based on in-situ activated carbon purification as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: At least one stream of amine solution is diverted from the amine solution circulation pipeline; S2: The diverted amine solution flows through the activated carbon adsorption unit, where degradation products and thermally stable salts in the amine solution are adsorbed and removed by the activated carbon. S3: The purified amine solution is returned to the amine solution circulation pipeline; S4: When the activated carbon is saturated, switch to the parallel standby adsorption unit and regenerate or replace the saturated activated carbon.
9. The amine regeneration method of the amine regeneration system based on in-situ activated carbon purification as described in claim 8, characterized in that: In step S1, when the amine solution that flows out is a single stream, it is either a rich amine solution or a lean amine solution. When the amine solution that flows out is two streams, they are respectively a rich amine solution and a lean amine solution. In step S2, the rich amine solution and the lean amine solution that flow out respectively flow through the rich solution activated carbon adsorption unit and the lean solution activated carbon adsorption unit.
10. The amine regeneration method of the amine regeneration system based on in-situ activated carbon purification as described in claim 8, characterized in that: The regeneration in step S4 is performed by steam purging.