CN-121971959-A - Technological system and technological method for capturing carbon dioxide by MOFs aqueous solution

CN121971959ACN 121971959 ACN121971959 ACN 121971959ACN-121971959-A

Abstract

The invention discloses a process system and a process method for capturing carbon dioxide by MOFs aqueous solution, and belongs to the technical field of carbon dioxide capturing. The system comprises a high-pressure absorption tower, a lean-rich liquid temperature and pressure energy regenerating module, a falling film desorption tower, an atmospheric desorption tower and a carbon dioxide compressor unit which are sequentially connected through pipelines to form a circulation loop, wherein MOFs aqueous solution is adopted to carry out high-efficiency carbon trapping on carbon source gas with certain pressure, the carbon trapping is carried out on the high-pressure absorption tower, the gas after carbon trapping is discharged from the tower top, and the MOFs aqueous solution rich in carbon dioxide is subjected to high-efficiency separation in the falling film desorption tower and the atmospheric desorption tower after being subjected to temperature and pressure energy regenerating, and carbon dioxide products meeting requirements are obtained through the carbon dioxide compressor unit. The process system utilizes the characteristics of MOFs aqueous solution and the pressure of a carbon source to absorb at a higher pressure, then reduces the pressure and the desorption temperature, achieves the purposes of energy conservation and consumption reduction, and reduces the operation cost.

Inventors

ZHAO YONG
YU YAO
LIU DAI
FENG LINHAO
ZHANG BOWEN
LV WEI
ZHANG CHAO
ZHUO QIANG
XU PO
ZHAO ZIYING
SHI ZHUANG
XIE ZHENWEI
ZHANG HUA
LENG XUEBING
ZHOU YINGJIAN
Yue Yanlong

Assignees

中国石油天然气集团有限公司
中国昆仑工程有限公司
中国昆仑环境工程有限公司

Dates

Publication Date: 20260505
Application Date: 20260120

Claims (10)

1. A process system for capturing carbon dioxide by MOFs aqueous solution is characterized by comprising a high-pressure absorption tower (1), a lean-rich liquid temperature-pressure refreshing module (2), a falling film desorption tower (3), an atmospheric pressure desorption tower (4) and a carbon dioxide compressor unit (5) which are sequentially connected through pipelines to form a circulation loop; the high-pressure absorption tower (1) is provided with a carbon dioxide-containing raw material gas inlet and a rich liquid outlet close to the tower bottom, and a purified gas outlet and a lean liquid inlet are arranged on the tower top; The rich liquid outlet of the high-pressure absorption tower (1) is connected to the rich liquid side inlet of the lean and rich liquid temperature and pressure refreshing module (2) through a pipeline, and the rich liquid side outlet of the lean and rich liquid temperature and pressure refreshing module (2) is connected to the feed inlet of the falling film desorption tower (3); the tower bottom liquid phase outlet of the falling film desorption tower (3) is connected to the feed inlet of the normal pressure desorption tower (4) through a pipeline, and the tower top gas phase outlet of the falling film desorption tower is connected to the secondary inlet of the carbon dioxide compressor unit (5); The tower kettle liquid phase outlet of the normal pressure desorption tower (4) is sequentially connected with a lean liquid pump (6) and a lean liquid side inlet of the lean and rich liquid temperature and pressure energy regeneration module (2) through pipelines, and the lean liquid side outlet of the lean and rich liquid temperature and pressure energy regeneration module (2) is connected back to the lean liquid inlet of the high pressure absorption tower (1); The top gas phase outlet of the normal pressure desorption tower (4) is connected to the primary inlet of the carbon dioxide compressor unit (5).
2. The process system according to claim 1, wherein the lean-rich liquid temperature and pressure rejuvenation module (2) comprises a hydraulic turbine unit (21) and a lean-rich liquid heat exchanger (22); A driving fluid inlet of the hydraulic turbine device (21) is connected with a rich liquid outlet of the high-pressure absorption tower (1), and a driving fluid outlet of the hydraulic turbine device is connected with a rich liquid side inlet of the lean and rich liquid heat exchanger (22); The rich liquid side outlet of the lean and rich liquid heat exchanger (22) is connected with the feed inlet of the falling film desorption tower (3); The outlet of the lean solution pump (6) is connected with the lean solution side inlet of the lean solution heat exchanger (22), and the lean solution side outlet of the lean solution heat exchanger (22) is connected back to the lean solution inlet of the high-pressure absorption tower (1) through a lean solution cooler (7).
3. Process system according to claim 1, wherein the carbon dioxide compressor train (5) is at least a two-stage compressor; The gas phase outlet at the top of the falling film desorption tower (3) is connected to the air suction port of the second stage or higher stage of the compressor unit (5); The gas phase outlet at the top of the normal pressure desorption tower (4) is connected to the first stage air suction port of the compressor unit.
4. The process system according to claim 1, characterized in that the top of the high-pressure absorption tower (1) is also provided with a rinsing section, which is provided with a demineralized water spraying device for washing the rising purge gas.
5. The process system according to claim 1, wherein the falling film desorber (3) comprises a first tower shell (31), a falling film heat exchange tube (32) arranged at the lower part of the first tower shell, a first leaching filler section (33) arranged at the upper part of the first tower shell and a first inclined plate demister (34) arranged at the top; the feed inlet of the falling film desorption tower (3) is communicated with the top of the falling film heat exchange tube (32) through a liquid distributor (35); A first umbrella cap (36) is also arranged between the first leaching filling section (33) and the liquid distributor (35).
6. The process system of claim 5, wherein a steam or heat medium heating jacket is provided outside the tube bundle (32) for heating the MOFs rich liquid flowing in the tube.
7. The process system according to claim 5, wherein the falling film heat exchange tube bundle (32) has an outer diameter of 25-50 mm and a length of 3-8 m, and the liquid distributor is formed by combining spraying, inclined holes and overflow.
8. Process system according to claim 1, characterized in that the atmospheric stripper column (4) comprises a second column shell (41), at least one overflow flash evaporation element (42) arranged in the lower part of the second column shell, a second leached packing segment (43) arranged in the upper part of the column shell and a second inclined plate demister (44) arranged at the top; the feed inlet of the normal pressure desorption tower (4) is communicated with the inlet of the overflow flash evaporation piece (42); A second umbrella cap (45) is arranged between the second leaching filling section (43) and the overflow type flash evaporation piece (42).
9. The process system according to claim 8, wherein the overflow flash evaporation member (42) has a horn mouth structure configured such that a desorption liquid from the falling film desorption tower (3) forms a liquid film by a pressure difference, and flash desorption is performed under normal pressure or a slight negative pressure.
10. A process for carbon dioxide capture in MOFs aqueous solution using the process system according to any one of claims 1 to 9, characterized by comprising the steps of: s1, introducing carbon dioxide-containing gas with the pressure not lower than 3 barg from a feed gas inlet of a high-pressure absorption tower, countercurrent contacting with lean MOFs solution entering from the top of the tower to absorb carbon dioxide, discharging purified gas from the top of the tower, and discharging rich liquid from the bottom of the tower; S2, introducing the rich liquid discharged in the step S1 into a lean and rich liquid temperature and pressure energy regeneration module, and sequentially recovering pressure energy and heat energy to obtain preheated rich liquid; S3, introducing the preheated rich liquid into a falling film desorption tower, and performing primary depressurization desorption at an operating pressure of 2-5 barg and an operating temperature of 70-90 ℃ to obtain primary desorption carbon dioxide gas and primary desorption liquid; s4, introducing the primary desorption solution obtained in the step S3 into an atmospheric pressure desorption tower, and carrying out secondary flash evaporation desorption under atmospheric pressure or micro negative pressure to obtain secondary desorption carbon dioxide gas and regenerated lean MOFs solution; s5, respectively sending the primary carbon dioxide gas and the secondary carbon dioxide gas desorbed in the steps S3 and S4 into different stage inlets of a carbon dioxide compressor unit, and compressing to obtain carbon dioxide as a product; S6, pressurizing the lean MOFs solution obtained in the step S4, exchanging heat with rich liquid in a lean-rich liquid temperature and pressure energy regenerating module, cooling, and conveying the lean MOFs solution back to the top of the high-pressure absorption tower to complete circulation.

Description

Technological system and technological method for capturing carbon dioxide by MOFs aqueous solution Technical Field The invention relates to the technical field of carbon dioxide trapping and resource utilization, in particular to a process system and a process method for trapping carbon dioxide by using a Metal Organic Framework (MOFs) aqueous solution, which are particularly suitable for carbon sources containing carbon dioxide gas with the pressure not lower than 3 barg, and realize low-cost and high-efficiency carbon trapping. Background Carbon dioxide trapping is a key technology for coping with global climate change, and the traditional method such as pressure swing adsorption (VPSA) relies on a plurality of groups of adsorbents such as adsorbent beds and activated carbon, and has the problems of frequent adsorption/desorption switching operation, high energy consumption and narrow application range. In recent years, metal organic framework Materials (MOFs) are considered as ideal adsorbents due to their high specific surface area and tunable pore structure, but the prior studies have focused on material preparation (such as the mixed absorption-adsorption method reported in 2014, "Nature Communications", or MOFs development reviewed in 2024, "fine chemical engineering"), lacking mature process flows and equipment integration. Patent document CN111821955A, for example, "a composite material for carbon dioxide adsorption separation and a preparation method thereof," still uses materials as main materials, and does not solve the problem of high energy consumption of the system. Disclosure of Invention In view of the above, the present invention has been made in order to provide a process system and a process method for carbon dioxide capture with an aqueous metal organic framework Material (MOFs) solution that overcomes or at least partially solves the above-mentioned problems. The embodiment of the invention provides a process system for capturing carbon dioxide by MOFs water solution, which comprises the following steps: the high-pressure absorption tower, the lean-rich liquid temperature and pressure energy regenerating module, the falling film desorption tower, the normal-pressure desorption tower and the carbon dioxide compressor unit which form a circulation loop are sequentially connected through pipelines; The high-pressure absorption tower is provided with a carbon dioxide-containing raw material gas inlet and a rich liquid outlet close to the tower bottom, and the tower top is provided with a purified gas outlet and a lean liquid inlet; The rich liquid outlet of the high-pressure absorption tower is connected to the rich liquid side inlet of the lean and rich liquid temperature and pressure energy regenerating module through a pipeline, and the rich liquid side outlet of the lean and rich liquid temperature and pressure energy regenerating module is connected to the feed inlet of the falling film desorption tower; the tower bottom liquid phase outlet of the falling film desorption tower is connected to the feed inlet of the normal pressure desorption tower through a pipeline, and the tower top gas phase outlet of the falling film desorption tower is connected to the secondary inlet of the carbon dioxide compressor unit; the tower bottom liquid phase outlet of the normal pressure desorption tower is sequentially connected with a lean liquid pump and a lean liquid side inlet of the lean and rich liquid temperature and pressure energy regeneration module through pipelines, and the lean liquid side outlet of the lean and rich liquid temperature and pressure energy regeneration module is connected back to the lean liquid inlet of the high pressure absorption tower; the top gas phase outlet of the normal pressure desorption tower is connected to the first-stage inlet of the carbon dioxide compressor unit. In one embodiment, the lean-rich liquid temperature and pressure rejuvenation module comprises a hydraulic turbine device and a lean-rich liquid heat exchanger; a driving fluid inlet of the hydraulic turbine device is connected with a rich liquid outlet of the high-pressure absorption tower, and a driving fluid outlet of the hydraulic turbine device is connected with a rich liquid side inlet of the lean rich liquid heat exchanger; The rich liquid side outlet of the lean and rich liquid heat exchanger is connected with the feed inlet of the falling film desorption tower; And an outlet of the lean solution pump is connected with a lean solution side inlet of the lean-rich solution heat exchanger, and a lean solution side outlet of the lean-rich solution heat exchanger is connected back to a lean solution inlet of the high-pressure absorption tower through a lean solution cooler. In one embodiment, the carbon dioxide compressor train is at least a two-stage compressor; the gas phase outlet at the top of the falling film desorption tower is connected to the air suction port of the second stage or highe