Carbon dioxide chemical absorption capture polygeneration complementary regeneration heating system and method

Abstract

The application provides a carbon dioxide chemical absorption capture multi-energy complementary regeneration heating system and method, belongs to the field of carbon dioxide capture, and comprises a pre-washing tower, a circulating device, an absorption tower, a lean liquid circulating device, a rich liquid pump, a phase separator, a lean-rich liquid heat exchanger, a lean liquid pump, a desorption tower, a cooling reflux device, an energy comprehensive utilization unit, a rich liquid pipe and a lean liquid pipe. The system is provided with the phase separator, mixed liquid at the bottom of the absorption tower is separated by the phase separator, the liquid amount entering the desorption tower is reduced, and the energy consumption required for heating is saved; the lean liquid generated after desorption enters the lean-rich liquid exchanger through the lean liquid pipe and exchanges heat with the rich liquid in the rich liquid pipe, the heat of the lean liquid is fully utilized, and the energy consumption required for subsequent heating of the rich liquid is saved; the method utilizes the heat of the oilfield produced liquid to desorb the rich liquid, and the energy consumption required for desorption of the rich liquid is saved.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide capture, and particularly relates to a multi-energy complementary regeneration heating system and method for carbon dioxide chemical absorption capture. Background Technology

[0002] In accordance with the "dual carbon" strategic goals and international environmental requirements, it is necessary to continuously reduce carbon dioxide emissions in the future. Conventional oil and gas field production processes generate large amounts of carbon dioxide, which is highly detrimental to environmental protection. How to "turn waste into treasure" and achieve the recycling and reuse of carbon dioxide has become a key challenge for the oil and gas production sector.

[0003] To promote the development of the CCUS (Continuous Coal Fusion System) industry in oilfields and meet the needs of carbon dioxide flooding injection, it is necessary to capture carbon dioxide in the flue gas emitted from circulating fluidized bed (CFB) boilers. The carbon concentration in the flue gas emitted from CFB boilers is relatively low. Based on the current state of technological development both domestically and internationally, the commonly used method for capturing low-concentration carbon dioxide is chemical absorption, which is further classified according to the absorbent into methods such as monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). However, this method suffers from high regeneration energy consumption and high costs, limiting its widespread adoption and application.

[0004] Chinese invention patent CN 104826472 B discloses a flue gas carbon dioxide capture and recovery system, which includes: a flue gas waste heat recovery heat exchanger, an absorption tower, a rich liquor pump, an interstage circulation pump of the absorption tower, an interstage circulation heat exchanger of the absorption tower, a first-stage lean-rich liquor heat exchanger, a rich liquor distributor, a second-stage lean-rich liquor heat exchanger, a desorption tower, a boiler, a flash tank, a bottom steam compressor of the desorption tower, a lean liquor pump, an interstage circulation heat exchanger of the desorption tower, and a lean liquor cooler. In the flue gas carbon dioxide capture and recovery system according to this invention, seven heat exchanges are performed, thereby improving the energy utilization rate of the flue gas carbon dioxide capture and recovery system and reducing the demand for external utility heat during desorption. The desorption process of this recovery system involves heating the rich liquor through a boiler to achieve carbon dioxide separation. The boiler consumes a large amount of energy, which is not conducive to cost control of the carbon dioxide capture and recovery system. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a multi-energy complementary regeneration heating process for carbon dioxide chemical absorption and capture. The technical problem to be solved by this invention is how to reduce the energy consumption for capturing low-concentration carbon dioxide emitted from circulating fluidized bed boilers in oilfield production.

[0006] To solve the above-mentioned technical problems, the present invention provides a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system, characterized in that it includes a pre-washing tower, a circulation device, an absorption tower, a lean liquid circulation device, a rich liquid pump, a phase separator, a lean and rich liquid heat exchanger, a lean liquid pump, a desorption tower, a cooling reflux device, an energy comprehensive utilization unit, a rich liquid pipe, and a lean liquid pipe.

[0007] The rich solution pump includes a first rich solution pump and a second rich solution pump.

[0008] The pre-washing tower and the circulation equipment are connected by pipelines to form a circulation loop. The outlet of the pre-washing tower is connected to the absorption tower, and the inlet of the absorption tower is connected to the lean liquid circulation device. The lean liquid circulation device is connected to the bottom of the desorption tower through a lean liquid pipe. The bottom of the absorption tower is connected in sequence to the first rich liquid pump, the phase separator, and the second rich liquid pump. The inlet of the lean liquid circulation device is connected to the phase separator, and the second rich liquid pump is connected to the desorption tower through a rich liquid pipe. Both the rich liquid pipe and the lean liquid pipe are equipped with lean-rich liquid heat exchangers to exchange heat between the liquid in the rich liquid pipe and the liquid in the lean liquid pipe. The lean liquid pump is located on the lean liquid pipe between the lean-rich liquid heat exchanger and the desorption tower. The outlet of the desorption tower is connected to the cooling reflux equipment. The lower part of the desorption tower is connected to the energy comprehensive utilization unit.

[0009] Furthermore, the energy comprehensive utilization unit includes a steam separator, a steam thermal oil heat exchanger, a produced fluid thermal oil heat exchanger, a thermal oil rich liquid heat exchanger, a thermal oil pipeline, and a desorption heating pipe. The thermal oil pipeline is a closed loop. One outlet of the steam separator is connected to the steam thermal oil heat exchanger, and the other outlet of the steam separator is connected to the produced fluid thermal oil heat exchanger. The steam thermal oil heat exchanger, the produced fluid thermal oil heat exchanger, and the thermal oil rich liquid heat exchanger are all installed on the thermal oil pipeline. The thermal oil rich liquid heat exchanger is connected to the desorption heating pipe, and the desorption heating pipe is connected to the lower part of the desorption tower.

[0010] Furthermore, the energy utilization unit includes an external steam heat exchanger, which is installed on the desorption heating tube.

[0011] Furthermore, the heat transfer oil pipeline includes a first branch, a second branch, and a collection pipeline. The steam heat transfer oil heat exchanger is installed on the first branch, the produced liquid heat transfer oil heat exchanger is installed on the second branch, the first branch and the second branch merge with the collection pipeline, and the heat transfer oil rich liquid heat exchanger is installed on the collection pipeline.

[0012] Furthermore, the desorption heating tube includes a first desorption heating tube and a second desorption heating tube, which are respectively arranged on both sides of the desorption tower. The heat transfer oil rich liquid heat exchanger is arranged on the first desorption heating tube, and the external steam heat exchanger is arranged on the second desorption heating tube.

[0013] Furthermore, a heat transfer oil pump is also installed on the collection pipeline.

[0014] Furthermore, a ridge demister is installed inside the pre-washing tower.

[0015] Furthermore, a feed pipe is connected to one side of the pre-washing tower.

[0016] Furthermore, an alkali injection skid is connected above the feed pipe.

[0017] Furthermore, the lean liquor circulation device includes a lean liquor cooler, a lean phase pump, a lean liquor tank, and a lean liquor feed pump. The lean liquor feed pump, lean liquor tank, lean phase pump, and lean liquor cooler are connected in sequence on one side of the absorption tower. The lean liquor cooler is connected to the desorption tower through a lean liquor pipe.

[0018] Furthermore, the cooling reflux equipment includes a desorption tower cooler, a reflux pump, and a reflux tank, with the upper part of the desorption tower sequentially connected to the desorption tower cooler, the reflux tank, and the reflux pump.

[0019] Furthermore, the circulation equipment includes a circulation pump and a circulation cooler, with the circulation pump and circulation cooler connected in sequence at the bottom of the pre-washing tower.

[0020] A carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating method, used in the aforementioned carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system, includes the following steps:

[0021] Step S1: Introduce the flue gas from the circulating fluidized bed boiler into the pre-scrubbing tower for cooling, impurity removal, and sulfur dioxide absorption;

[0022] Step S2: The flue gas treated in step S1 flows into the absorption tower and contacts the lean liquid to achieve the absorption of carbon dioxide in the flue gas.

[0023] Step S3: The lean liquid reacts with carbon dioxide to generate a rich liquid. The mixture of lean and rich liquids flows out from the bottom of the absorption tower and enters the phase separator to be separated into lean and rich liquids. The lean liquid flows back into the absorption tower, and the rich liquid enters the desorption tower.

[0024] Step S4: After the rich liquid is heated by the energy comprehensive utilization unit, carbon dioxide and lean liquid are separated. Part of the carbon dioxide enters the carbon dioxide pressurization unit, and the other part of the carbon dioxide returns to the desorption tower. The lean liquid flows into the lean liquid circulation device.

[0025] Furthermore, in step S4, the energy comprehensive utilization unit separates the oilfield produced fluid into a gas phase and a liquid phase. Then, the gas phase and the liquid phase exchange heat with the heat transfer oil, and the heat transfer oil exchanges heat with the rich fluid to achieve carbon dioxide desorption. When the heat of the oilfield produced fluid is insufficient to complete the desorption, external steam is introduced into the external steam heat exchanger to achieve carbon dioxide desorption.

[0026] Furthermore, in step S4, carbon dioxide first flows into the cooling reflux device for processing, then liquid carbon dioxide is pressurized, gaseous carbon dioxide returns to the desorption tower, and lean liquid flows out of the desorption tower, first exchanges heat with the rich liquid in the rich liquid pipe through the lean-rich liquid heat exchanger, and then flows into the lean liquid circulation device.

[0027] This invention discloses a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system. A phase separator separates the mixed liquid at the bottom of the absorption tower. The separated lean liquid circulates back into the absorption tower, while the separated rich liquid enters a desorption tower for heating and desorption. This reduces the amount of liquid entering the desorption tower, saving energy consumption for heating. The resulting lean liquid enters a lean-rich liquid exchanger through a lean liquid pipe, exchanging heat with the rich liquid in the rich liquid pipe. This fully utilizes the heat of the lean liquid, saving energy consumption for subsequent heating of the rich liquid. Furthermore, an energy utilization unit utilizes the heat of the oilfield produced fluid for the desorption of the rich liquid, further reducing the energy consumption for rich liquid desorption.

[0028] This invention discloses a multi-energy complementary regeneration heating method for carbon dioxide chemical absorption and capture. By separating the mixed liquid of rich and lean solutions, the energy consumption of heating and desorption in the subsequent desorption tower is reduced. By exchanging heat between the lean solution generated after desorption and the rich solution in the rich solution pipe, the temperature of the lean solution is reduced, the cooling efficiency of the lean solution is improved, and the rich solution is heated at the same time, which reduces the energy consumption of heating and desorption in the subsequent desorption tower. The heat of the oilfield produced fluid is used to desorb the rich solution, saving the energy required for the desorption of the rich solution. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of an embodiment of a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to the present invention.

[0030] Figure 2 This is a schematic diagram of the energy utilization unit of a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to the present invention.

[0031] Among them, 1-pre-washing tower; 2-circulation equipment; 3-absorption tower; 4-lean liquor circulation device; 5-rich liquor pump; 6-phase separator; 7-lean-rich liquor heat exchanger; 8-lean liquor pump; 9-desorption tower; 10-cooling reflux equipment; 11-energy comprehensive utilization unit; 21-circulation pump; 22-circulating liquid cooler; 41-lean liquor cooler; 42-lean phase pump; 43-lean liquor tank; 44-lean liquor feed pump; 51-first rich liquor pump; 52-second rich liquor pump; 101-desorption tower cooler ; 102-Recirculation pump; 103-Recirculation tank; 111-Steam separator; 112-Steam-heat transfer oil heat exchanger; 113-Produced fluid-heat transfer oil heat exchanger; 114-Heat transfer oil rich liquid heat exchanger; 115-Heat transfer oil pipeline; 116-External steam heat exchanger; 117-Heat transfer oil pump; 118-Desorption heating pipe; 1151-First branch; 1152-Second branch; 1153-Gathering pipeline; 1181-First desorption heating pipe; 1182-Second desorption heating pipe. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] To better understand the purpose, structure, and function of this invention, the following detailed description of a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system and method, in conjunction with the accompanying drawings, is provided.

[0037] Example 1:

[0038] Figure 1 This invention illustrates a first embodiment of a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system, comprising a pre-washing tower 1, a circulation device 2, an absorption tower 3, a lean liquid circulation device 4, a rich liquid pump 5, a phase separator 6, a lean and rich liquid heat exchanger 7, a lean liquid pump 8, a desorption tower 9, a cooling reflux device 10, an energy comprehensive utilization unit 11, a rich liquid pipe 12, and a lean liquid pipe 13.

[0039] The rich solution pump 5 includes a first rich solution pump 51 and a second rich solution pump 52;

[0040] The pre-washing tower 1 and the circulation device 2 are connected by pipelines to form a circulation loop; the outlet of the pre-washing tower 1 is connected to the absorption tower 3, the inlet of the absorption tower 3 is connected to the lean liquid circulation device 4 by pipelines, the lean liquid circulation device 4 is connected to the bottom of the desorption tower 9 through the lean liquid pipe 13, the bottom of the absorption tower 3 is connected in sequence to the first rich liquid pump 51, the phase separator 6 and the second rich liquid pump 52, the inlet of the lean liquid circulation device 4 is connected to the phase separator 6, and the second rich liquid pump 52 is connected to the side wall of the desorption tower 9 through the rich liquid pipe 12; the lean-rich liquid heat exchanger 7 is installed on both the rich liquid pipe 12 and the lean liquid pipe 13 to exchange heat between the liquid in the rich liquid pipe 12 and the liquid in the lean liquid pipe 13; the lean liquid pump 8 is installed on the lean liquid pipe 13 between the lean-rich liquid heat exchanger 7 and the desorption tower 9; the outlet of the desorption tower 9 is connected to the cooling reflux device 10; the lower part of the desorption tower 9 is connected to the energy comprehensive utilization unit 11;

[0041] The phase separator 6 separates the liquid flowing from the bottom of the absorption tower 3 into two phases, which then flow into the lean liquid circulation device 4 and the second rich liquid pump 52.

[0042] Example 2:

[0043] Figure 1 This invention illustrates a second embodiment of a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system, comprising a pre-washing tower 1, a circulation device 2, an absorption tower 3, a lean liquid circulation device 4, a rich liquid pump 5, a phase separator 6, a lean and rich liquid heat exchanger 7, a lean liquid pump 8, a desorption tower 9, a cooling reflux device 10, an energy comprehensive utilization unit 11, a rich liquid pipe 12, and a lean liquid pipe 13.

[0044] The rich solution pump 5 includes a first rich solution pump 51 and a second rich solution pump 52;

[0045] The pre-washing tower 1 and the circulation device 2 are connected by pipelines to form a circulation loop; the outlet of the pre-washing tower 1 is connected to the absorption tower 3, the inlet of the absorption tower 3 is connected to the lean liquid circulation device 4 by pipelines, the lean liquid circulation device 4 is connected to the bottom of the desorption tower 9 through the lean liquid pipe 13, the bottom of the absorption tower 3 is connected in sequence to the first rich liquid pump 51, the phase separator 6 and the second rich liquid pump 52, the inlet of the lean liquid circulation device 4 is connected to the phase separator 6, and the second rich liquid pump 52 is connected to the side wall of the desorption tower 9 through the rich liquid pipe 12; the lean-rich liquid heat exchanger 7 is installed on both the rich liquid pipe 12 and the lean liquid pipe 13 to exchange heat between the liquid in the rich liquid pipe 12 and the liquid in the lean liquid pipe 13; the lean liquid pump 8 is installed on the lean liquid pipe 13 between the lean-rich liquid heat exchanger 7 and the desorption tower 9; the outlet of the desorption tower 9 is connected to the cooling reflux device 10; the lower part of the desorption tower 9 is connected to the energy comprehensive utilization unit 11;

[0046] The phase separator 6 separates the liquid flowing from the bottom of the absorption tower 3 into two phases, which then flow into the lean liquid circulation device 4 and the second rich liquid pump 52.

[0047] The difference between this embodiment and the first embodiment is that:

[0048] The lean liquor circulation device 4 includes a lean liquor cooler 41, a lean phase pump 42, a lean liquor tank 43, and a lean liquor feed pump 44. The lean liquor feed pump 44, the lean liquor tank 43, the lean phase pump 42, and the lean liquor cooler 41 are connected in sequence on one side of the absorption tower 3. The lean liquor cooler 41 is connected to the desorption tower 9 through the lean liquor pipe 13.

[0049] The cooling reflux device 10 includes a desorption tower cooler 101, a reflux pump 102, and a reflux tank 103. The upper part of the desorption tower 9 is connected in sequence to the desorption tower cooler 101, the reflux tank 103, and the reflux pump 102. The carbon dioxide desorbed by the desorption tower 9 is cooled by the desorption tower cooler 101 and then enters the reflux tank 103. Liquid carbon dioxide flows into the carbon dioxide pressurization unit from one outlet of the reflux tank 103, while gaseous carbon dioxide flows out from the other outlet of the reflux tank 103 and flows back into the desorption tower 9 via the reflux pump 102 to assist in the desorption of subsequent gases.

[0050] The circulation device 2 includes a circulation pump 21 and a circulation cooler 22. The liquid flowing out from the bottom of the pre-washing tower 1 flows through the circulation pump 21 and the circulation cooler 22 in sequence, and then flows back into the pre-washing tower 1.

[0051] The phase separator 6 separates the liquid flowing from the bottom of the absorption tower 3 into two phases, which then flow into the lean phase pump 42 and the second rich phase pump 52.

[0052] Example 3:

[0053] Figure 1This invention illustrates a third embodiment of a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system, comprising a pre-washing tower 1, a circulation device 2, an absorption tower 3, a lean liquid circulation device 4, a rich liquid pump 5, a phase separator 6, a lean and rich liquid heat exchanger 7, a lean liquid pump 8, a desorption tower 9, a cooling reflux device 10, an energy comprehensive utilization unit 11, a rich liquid pipe 12, and a lean liquid pipe 13.

[0054] The rich solution pump 5 includes a first rich solution pump 51 and a second rich solution pump 52;

[0055] The pre-washing tower 1 and the circulation device 2 are connected by pipelines to form a circulation loop; the outlet of the pre-washing tower 1 is connected to the absorption tower 3, the inlet of the absorption tower 3 is connected to the lean liquid circulation device 4 by pipelines, the lean liquid circulation device 4 is connected to the bottom of the desorption tower 9 through the lean liquid pipe 13, the bottom of the absorption tower 3 is connected in sequence to the first rich liquid pump 51, the phase separator 6 and the second rich liquid pump 52, the inlet of the lean liquid circulation device 4 is connected to the phase separator 6, and the second rich liquid pump 52 is connected to the side wall of the desorption tower 9 through the rich liquid pipe 12; the lean-rich liquid heat exchanger 7 is installed on both the rich liquid pipe 12 and the lean liquid pipe 13 to exchange heat between the liquid in the rich liquid pipe 12 and the liquid in the lean liquid pipe 13; the lean liquid pump 8 is installed on the lean liquid pipe 13 between the lean-rich liquid heat exchanger 7 and the desorption tower 9; the outlet of the desorption tower 9 is connected to the cooling reflux device 10; the lower part of the desorption tower 9 is connected to the energy comprehensive utilization unit 11;

[0056] The phase separator 6 separates the liquid flowing from the bottom of the absorption tower 3 into two phases, which then flow into the lean phase pump 42 and the second rich phase pump 52.

[0057] The difference between this embodiment and the above embodiments is that:

[0058] like Figure 2 As shown, the energy comprehensive utilization unit 11 includes a steam separator 111, a steam heat transfer oil heat exchanger 112, a produced fluid heat transfer oil heat exchanger 113, a heat transfer oil rich liquid heat exchanger 114, a heat transfer oil pipeline 115, an external steam heat exchanger 116, a heat transfer oil pump 117, and a desorption heating pipe 118.

[0059] The heat transfer oil pipeline 115 is a closed loop. One outlet of the steam separator 111 is connected to the steam heat transfer oil heat exchanger 112, and the other outlet of the steam separator 111 is connected to the produced fluid heat transfer oil heat exchanger 113. The steam heat transfer oil heat exchanger 112, the produced fluid heat transfer oil heat exchanger 113, and the heat transfer oil rich liquid heat exchanger 114 are all installed on the heat transfer oil pipeline 115. The heat transfer oil rich liquid heat exchanger 114 is also connected to the desorption heating pipe 118. The desorption heating pipe 118 is connected to the lower part of the desorption tower 9. An external steam heat exchanger 116 is also installed on the desorption heating pipe 118.

[0060] The heat transfer oil pipeline 115 includes a first branch 1151, a second branch 1152, and a collection pipeline 1153. A steam heat transfer oil heat exchanger 112 is installed on the first branch 1151, and a produced liquid heat transfer oil heat exchanger 113 is installed on the second branch 1152. The first branch 1151 and the second branch 1152 are branch structures of the collection pipeline. The liquids in the first branch 1151 and the second branch 1152 merge and enter the collection pipeline 1153. A heat transfer oil rich liquid heat exchanger 114 is installed on the collection pipeline 1153.

[0061] The desorption heating tube 118 includes a first desorption heating tube 1181 and a second desorption heating tube 1182. The first desorption heating tube 1181 and the second desorption heating tube 1182 are respectively arranged on both sides of the desorption tower 9. The heat transfer oil rich liquid heat exchanger 114 is arranged on the first desorption heating tube 1181, and the external steam heat exchanger 116 is arranged on the second desorption heating tube 1182.

[0062] The pre-washing tower 1 is equipped with a ridge demister and nozzles. The nozzles are connected to the outlet of the circulation equipment 2. The washing liquid enters the pre-washing tower 1 through the nozzles and comes into counter-current contact with the flue gas.

[0063] A feed pipe is connected to one side of the pre-washing tower 1, through which flue gas enters the interior of the pre-washing tower 1. To treat sulfur dioxide in the flue gas, an alkaline injection skid is connected above the feed pipe, through which workers inject sodium hydroxide solution into the feed pipe.

[0064] The working process of a carbon dioxide chemical absorption and capture multi-energy complementary regenerative heating system in this embodiment is as follows:

[0065] The flue gas from the circulating fluidized bed boiler, destined for the high-level chimney, is pressurized by an induced draft fan and then drawn out. Workers add a 20% NaOH solution to the feed pipe via an alkali injection skid (alkali injection pump) to remove sulfur dioxide from the flue gas. The flue gas and NaOH solution then enter the pre-washing tower 1 through the feed pipe. The flue gas comes into counter-current contact with the washing liquid sprayed from nozzles located at the top of the pre-washing tower 1. The washing liquid, upon exiting the nozzles, forms a foam zone upon contact with the flue gas. This highly turbulent standing wave foam zone is generated by the high mass transfer between droplets and gas. The foam zone continuously cools the droplets, rapidly cooling the flue gas and absorbing sulfur dioxide. The washing liquid then flows to the bottom of the tower, is processed by the circulation equipment 2, and is sprayed back into the pre-washing tower 1 through the nozzles. The washed and cooled flue gas then enters the ridge demister inside the pre-washing tower 1 to remove entrained droplets before entering the absorption tower 3.

[0066] After cooling and impurity removal, the flue gas enters the absorption tower 3. The absorbent that has not absorbed carbon dioxide (hereinafter referred to as lean liquid) in the lean liquid tank 43 is pressurized by the lean liquid feed pump 44 and enters the top of the absorption tower 3. It is sprayed downward from the top of the packing inside the tower and comes into counter-current contact with the flue gas to absorb carbon dioxide in the flue gas. The carbon dioxide removal efficiency of the flue gas is as high as 99%. The flue gas after absorption meets the standards and is discharged into the atmosphere. The "absorbent" after absorbing carbon dioxide is called rich "absorbent" (hereinafter referred to as rich liquid). The mixed solution of rich liquid and lean liquid flows out of the absorption tower 3 and is transported to the phase separator by the first rich liquid pump 51 to separate into lean liquid and rich liquid. The lean liquid flows back to the lean liquid tank 43 by the lean phase pump 42, and the rich liquid flows into the desorption tower 9 after heat exchange by the second rich liquid pump 52 and the lean-rich liquid heat exchanger 7.

[0067] The rich liquor is sprayed from above the packing section inside the desorption tower 9. After being desorbed and heated at the bottom of the tower, the carbamate or bicarbonate decomposes to release carbon dioxide. The regenerated lean liquor is discharged from the bottom of the tower and pressurized by the lean liquor pump 8 before entering the lean-rich liquor heat exchanger 7. The higher-temperature lean liquor exchanges heat with the rich liquor inside the rich liquor tube 12 inside the lean-rich liquor heat exchanger 7. After being cooled by the lean liquor cooler 41, it merges with the lean liquor separated by the phase separator 6. After being mixed by the static mixer, it is transported to the lean liquor tank 43 and fed into the absorption tower 3 for recycling via the lean liquor feed pump 44. The desorbed carbon dioxide rises along the desorption tower 9 and is discharged from the top of the tower. It enters the desorption tower cooler 101 and is cooled to 50°C. Then it enters the reflux tank 103 for gas-liquid separation. The separated gaseous carbon dioxide flows back to the desorption tower 9 via the reflux pump 102, and the separated liquid carbon dioxide flows into the carbon dioxide pressurization unit.

[0068] The desorption of the rich liquid at the bottom of the desorption tower 9 is achieved by heating the energy comprehensive utilization unit 11. The oilfield produced fluid enters the steam separator 11 for separation. The separated steam enters the steam heat transfer oil heat exchanger 112 and exchanges heat with the heat transfer oil in the first branch 1151. The separated liquid enters the produced fluid heat transfer oil heat exchanger 113 and exchanges heat with the heat transfer oil in the second branch 1152. The heat transfer oil after heat exchange merges into the collection pipe 1153. The heat transfer oil enters the heat transfer oil rich liquid heat exchanger 114 and exchanges heat with the rich liquid inside the first desorption heating pipe 1181. After the rich liquid is heated, it decomposes into carbon dioxide.

[0069] When the heat provided by the oilfield produced fluid is insufficient for heat exchange, steam is introduced into the external steam heat exchanger 116 to exchange heat with the rich liquid in the second desorption heating pipe 1182. After the rich liquid is heated, it decomposes into carbon dioxide.

[0070] This invention discloses a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system. A phase separator 6 separates the mixed liquid at the bottom of the absorption tower 3 into phases. The separated lean liquid circulates back into the absorption tower, while the separated rich liquid enters the desorption tower 9 for heating and desorption. This reduces the volume of liquid entering the desorption tower 9, saving energy consumption for heating. The resulting lean liquid enters the lean-rich liquid exchanger 7 through the lean liquid pipe 13, exchanging heat with the rich liquid in the rich liquid pipe 12. This fully utilizes the heat of the lean liquid, saving energy consumption for subsequent heating of the rich liquid. Furthermore, an energy utilization unit 11 utilizes the heat of the oilfield produced fluid for the desorption of the rich liquid, further reducing the energy consumption for rich liquid desorption.

[0071] Example 4:

[0072] Figure 1 This invention discloses a carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating method for use in the above-mentioned carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system, comprising the following steps:

[0073] Step S1: Introduce the flue gas from the circulating fluidized bed boiler into the pre-scrubbing tower 1 for cooling, impurity removal, and sulfur dioxide absorption;

[0074] Step S2: The flue gas treated in step S1 flows into the absorption tower 3 and comes into contact with the lean liquid to achieve the absorption of carbon dioxide in the flue gas.

[0075] Step S3: The lean liquid reacts with carbon dioxide to generate a rich liquid. The mixture of lean and rich liquids flows out from the bottom of the absorption tower 3 and enters the phase separator 6 to be separated into lean and rich liquids. The lean liquid flows back into the absorption tower 3, and the rich liquid enters the desorption tower 9.

[0076] Step S4: After the rich liquid is heated by the energy comprehensive utilization unit, carbon dioxide and lean liquid are separated. Part of the carbon dioxide enters the carbon dioxide pressurization unit, and the other part of the carbon dioxide returns to the desorption tower 9. The lean liquid flows into the lean liquid circulation device 4.

[0077] Furthermore, in step S4, the energy comprehensive utilization unit 11 separates the oilfield produced fluid into a gas phase and a liquid phase. Then, the gas phase and the liquid phase exchange heat with the heat transfer oil, and the heat transfer oil exchanges heat with the rich fluid to achieve carbon dioxide desorption. When the heat of the oilfield produced fluid is insufficient to complete the desorption, external steam is introduced into the external steam heat exchanger 116 to achieve carbon dioxide desorption.

[0078] Furthermore, in step S4, carbon dioxide first flows into the cooling reflux device for processing, then liquid carbon dioxide enters the carbon dioxide pressurization unit, gaseous carbon dioxide returns to the desorption tower 9, and the lean liquid flows out of the desorption tower and first exchanges heat with the rich liquid in the rich liquid pipe 12 through the lean-rich liquid heat exchanger 7 before flowing into the lean liquid circulation device 4.

[0079] This invention discloses a multi-energy complementary regeneration heating method for carbon dioxide chemical absorption and capture. By separating the mixed liquid of rich and lean solutions, the energy consumption of heating and desorption in the subsequent desorption tower 9 is reduced. By exchanging heat between the lean solution generated after desorption and the rich solution in the rich solution pipe 12, the temperature of the lean solution is reduced, the cooling efficiency of the lean solution is improved, and the rich solution is heated at the same time, further reducing the energy consumption of heating and desorption in the subsequent desorption tower 9. The heat of the oilfield produced fluid is used to desorb the rich solution, saving the energy required for the desorption of the rich solution.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system, characterized in that, It includes a pre-washing tower, circulation equipment, absorption tower, lean liquor circulation device, rich liquor pump, phase separator, lean and rich liquor heat exchanger, lean liquor pump, desorption tower, cooling reflux equipment, energy comprehensive utilization unit, rich liquor pipe and lean liquor pipe; The rich solution pump includes a first rich solution pump and a second rich solution pump. The pre-washing tower and the circulation equipment are connected by pipelines to form a circulation loop. The gas outlet of the pre-washing tower is connected to the absorption tower, and the liquid inlet of the absorption tower is connected to the lean liquid circulation device. The lean liquid circulation device is connected to the bottom of the desorption tower through a lean liquid pipe. The bottom of the absorption tower is sequentially connected to the first rich liquid pump, the phase separator, and the second rich liquid pump. The liquid inlet of the lean liquid circulation device is connected to the phase separator, and the second rich liquid pump is connected to the desorption tower through a rich liquid pipe. Lean and rich liquid heat exchangers are installed on both the rich liquid pipe and the lean liquid pipe. The lean liquid pump is installed on the lean liquid pipe between the lean and rich liquid heat exchangers and the desorption tower. The gas outlet of the desorption tower is connected to the cooling reflux equipment. The lower part of the desorption tower is connected to the energy comprehensive utilization unit. The energy utilization unit includes a steam separator, a steam-heated oil heat exchanger, a produced fluid-heated oil heat exchanger, a rich-liquid heat exchanger, a heat transfer oil pipeline, and a desorption heating pipe. The heat transfer oil pipeline is a closed loop. One outlet of the steam separator is connected to the steam-heated oil heat exchanger, and the other outlet of the steam separator is connected to the produced fluid-heated oil heat exchanger. The steam-heated oil heat exchanger, the produced fluid-heated oil heat exchanger, and the rich-liquid heat exchanger are all located on the heat transfer oil pipeline. The rich-liquid heat exchanger is connected to the desorption heating pipe, and the desorption heating pipe is connected to the lower part of the desorption tower. The energy utilization unit also includes an external steam heat exchanger, which is installed on the desorption heating pipe. The heat transfer oil pipeline includes a first branch, a second branch, and a collection pipeline. The steam heat transfer oil heat exchanger is located on the first branch, and the produced liquid heat transfer oil heat exchanger is located on the second branch. The first and second branches merge with the collection pipeline, and the heat transfer oil rich liquid heat exchanger is located on the collection pipeline.

2. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 1, characterized in that, The desorption heating tube includes a first desorption heating tube and a second desorption heating tube, which are respectively arranged on both sides of the desorption tower. The heat transfer oil rich liquid heat exchanger is arranged on the first desorption heating tube, and the external steam heat exchanger is arranged on the second desorption heating tube.

3. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 2, characterized in that, A heat transfer oil pump is also installed on the collection pipeline.

4. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 1, characterized in that, The pre-washing tower is equipped with a ridge demister.

5. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 1, characterized in that, A feed pipe is connected to one side of the pre-washing tower.

6. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 5, characterized in that, An alkali solution injection skid is connected above the feed pipe.

7. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 1, characterized in that, The lean liquor circulation device includes a lean liquor cooler, a lean phase pump, a lean liquor tank, and a lean liquor feed pump. The lean liquor feed pump, lean liquor tank, lean phase pump, and lean liquor cooler are connected in sequence on one side of the absorption tower. The lean liquor cooler is connected to the desorption tower through a lean liquor pipe.

8. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 1, characterized in that, The cooling reflux equipment includes a desorption tower cooler, a reflux pump, and a reflux tank. The upper part of the desorption tower is connected to the desorption tower cooler, the reflux tank, and the reflux pump in sequence.

9. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating system according to claim 1, characterized in that, The circulating equipment includes a circulating pump and a circulating cooler, with the circulating pump and circulating cooler connected in sequence at the bottom of the pre-washing tower.

10. A multi-energy complementary regeneration heating method for carbon dioxide chemical absorption and capture, characterized in that, The carbon dioxide chemical absorption and capture multi-energy complementary regenerative heating system according to any one of claims 1-9 includes the following steps: Step S1: Introduce the flue gas from the circulating fluidized bed boiler into the pre-scrubbing tower for cooling, impurity removal, and sulfur dioxide absorption; Step S2: The flue gas treated in step S1 flows into the absorption tower and contacts the lean liquid to achieve the absorption of carbon dioxide in the flue gas. Step S3: The lean liquid reacts with carbon dioxide to generate a rich liquid. The mixture of lean and rich liquids flows out from the bottom of the absorption tower and enters the phase separator to be separated into lean and rich liquids. The lean liquid flows back into the absorption tower, and the rich liquid enters the desorption tower. Step S4: After the rich liquid is heated by the energy comprehensive utilization unit, carbon dioxide and lean liquid are separated. Part of the carbon dioxide enters the carbon dioxide pressurization unit, and the other part of the carbon dioxide returns to the desorption tower. The lean liquid flows into the lean liquid circulation device.

11. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating method according to claim 10, characterized in that, The energy utilization unit in step S4 separates the oilfield produced fluid into a gas phase and a liquid phase. Then, the gas phase and the liquid phase exchange heat with the heat transfer oil, and the heat transfer oil exchanges heat with the rich fluid to achieve carbon dioxide desorption. When the heat of the oilfield produced fluid is insufficient to complete the desorption, external steam is introduced into the external steam heat exchanger to achieve carbon dioxide desorption.

12. The carbon dioxide chemical absorption and capture multi-energy complementary regeneration heating method according to claim 10, characterized in that, In step S4, carbon dioxide first flows into the cooling reflux equipment for processing, then liquid carbon dioxide is pressurized, and gaseous carbon dioxide returns to the desorption tower. The lean liquid flows out of the desorption tower and first exchanges heat with the rich liquid in the rich liquid pipe through the lean-rich liquid heat exchanger before flowing into the lean liquid circulation device.

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