Flue gas deep purification system applied to CO2 trapping device

Abstract

The utility model discloses a flue gas deep purification system for a CO2 trapping device. The flue gas deep purification system is suitable for deep purification of front flue gas of the CO2 trapping device of a low-concentration low-pressure chemical absorption method (CCUS). The device mainly comprises a washing tower, tower internals, filler, accessory equipment, an instrument control system and the like. The washing tower mainly comprises a flue gas uniform distributor, three filler layers, a spraying device, a top wire mesh demister and other accessories; the accessory equipment comprises a circulating pump, a circulating liquid cooler, control instruments for temperature, pressure, flow and the like. The utility model has the advantages that the circulating flow can be adjusted and the liquid-gas ratio can be controlled and stabilized according to the amount load of flue gas entering the tower, the operation flexibility is high, and the purification efficiency is high; and the circulating pipeline is provided with the circulating liquid cooler, so that the temperature of the flue gas can be effectively reduced, and the absorption efficiency of the solvent amine in the subsequent process on CO2 is favorably improved.

Description

Technical Field

[0001] This invention belongs to the field of carbon neutrality technology and is mainly applied to CO2 capture systems in combustion exhaust gas, specifically a deep flue gas purification system applied to CO2 capture devices. Background Technology

[0002] Thermal power generation is my country's largest emitter of carbon dioxide, resulting in high levels of emissions. Carbon capture, utilization, and storage (CCUS) technology is a key means of reducing carbon emissions. Among these methods, chemical absorption, as a low-concentration carbon dioxide capture technique, is increasingly being used in the treatment of flue gas from thermal power plants.

[0003] Before absorbing carbon dioxide from flue gas, the chemical absorption carbon dioxide capture system requires the flue gas to be washed to remove trace amounts of dust, SO2, NOx and other acidic gases. A deep purification system is needed to wash the flue gas and remove the above impurities. The existing purification system is not effective and it is difficult to improve the subsequent CO2 absorption efficiency. Utility Model Content

[0004] To address the aforementioned technical problems, this invention provides a deep flue gas purification system for CO2 capture devices. This system can fully absorb residual dust and acidic gases such as SO2 and NOx in the flue gas, while simultaneously reducing the flue gas temperature. This helps to reduce the reaction and degradation of solvent amines with flue gas pollutants (such as SO2, NOx, and hydrocarbons) in the absorption tower, thereby increasing the absorption efficiency of solvent amines for CO2.

[0005] The specific technical structure of this utility model is as follows:

[0006] A deep flue gas purification system for a CO2 capture device includes a scrubbing tower and a circulating liquid system. The scrubbing tower includes a bottom scrubbing liquid storage area, a middle flue gas scrubbing section, an upper demister section, and a top outlet flue. The middle flue gas scrubbing section has a flue gas inlet at its lower part and a packing layer. The upper demister section includes a spray device, a packing layer, and a demister. The circulating liquid system includes a circulating liquid pipeline equipped with a circulating pump and a circulating liquid cooler. One end of the circulating liquid pipeline is connected to the bottom scrubbing liquid storage area, and the other end is connected to the spray device. An alkali addition port is provided on the circulating liquid pipeline.

[0007] A further feature is that each packing layer in the middle flue gas scrubbing section includes, from bottom to top, a support beam, a support grid, bulk packing, a pressing device, and a gas-liquid distributor, and each packing layer is provided with an anti-wall-adhering flow baffle ring at the bottom; the packing layer in the upper demisting section includes, from bottom to top, a support beam, a support grid, structured packing, and a pressing device.

[0008] The bottom washing liquid storage area is provided with a water inlet, a wastewater outlet, and a circulating liquid outlet, and the circulating liquid outlet is connected to one end of the circulating liquid pipeline.

[0009] The scrubbing tower is equipped with a flue gas distributor connected to the flue gas inlet, and a raw flue gas inlet pipe connected to the flue gas inlet is provided outside the scrubbing tower. A raw flue gas temperature sensor, a raw flue gas pressure sensor, a raw flue gas CO2 analyzer, and a raw flue gas flow meter are installed on the raw flue gas inlet pipe.

[0010] The bottom washing liquid storage area is equipped with a tower bottom liquid level sensor, a tower bottom liquid temperature sensor, and a pH sensor; the circulating liquid pipeline is equipped with a circulating liquid temperature sensor and a circulating liquid flow meter; and the middle flue gas scrubbing section is equipped with a flue gas pressure sensor.

[0011] The packing layer in the washing section of this invention is the main component for flue gas purification. By increasing the contact area between the gas and liquid phases on the surface of the packing layer, the washing efficiency of the washing liquid is improved. Adding an alkaline solution, such as sodium hydroxide solution, to the washing liquid further removes acidic gases such as SO2 and NOx from the flue gas, effectively reducing the degradation reaction of the absorbent in subsequent processes. The circulating liquid cooler further reduces the flue gas temperature, effectively improving the absorption efficiency of CO2 by the absorbent in subsequent processes. This invention can be applied to the pre-flue gas scrubbing system of low-concentration, low-pressure CO2 capture devices in coal-fired power plants, industrial boilers, lime kilns, etc. Attached Figure Description

[0012] Figure 1This is a schematic diagram of the flue gas deep purification system of the CO2 capture device of this utility model. The components include: 1. Scrubber; 2. Top outlet flue; 3. Flue gas distributor; 4. First layer anti-wall-adhesion baffle ring; 5. First layer packing layer; 6. First layer gas-liquid distributor; 7. Second layer anti-wall-adhesion baffle ring; 8. Second layer packing layer; 9. Second layer gas-liquid distributor; 10. Spray device; 11. Third layer packing layer; 12. Wire mesh demister; 13. Circulating pump; 14. Circulating liquid cooler; 15. Bottom level sensor; 16. Bottom liquid temperature sensor; 17. Raw flue gas temperature sensor; 18. Raw flue gas pressure sensor; 19. First layer pressure sensor; 20. Second layer pressure sensor; 21. Outlet temperature sensor; 22. Outlet pressure sensor; 23. Raw flue gas CO2 analyzer; 24. Raw flue gas flow meter; 25. Circulating liquid temperature sensor; 26. Circulating liquid flow meter; 27. pH sensor. Detailed Implementation

[0013] The features and advantages of this utility model are described in detail with reference to the accompanying drawings and examples. This utility model includes, but is not limited to, the content described in the accompanying drawings and specific embodiments, including non-essential auxiliary equipment and instruments not shown in the drawings.

[0014] like Figure 1 As shown in the figure, this embodiment demonstrates a deep flue gas purification system for a CO2 capture device.

[0015] The scrubbing tower 1 has a uniform cylindrical structure with a variable diameter section at the top, which connects to the top outlet flue 2. The original flue gas inlet flue is located on the lower side of the tower, and a flue gas distributor 3 is connected inside the scrubbing tower 1.

[0016] The raw flue gas is introduced into the lower part of the scrubbing tower 1 through the raw flue gas inlet pipe. After entering the scrubbing tower 1, the raw flue gas is evenly distributed across the cross-section of the absorption tower by the flue gas distributor 3. The flue gas distributor 3 is generally a double-row blade gas distributor. The flue gas flows from bottom to top, passing sequentially through the first packing layer 5, the second packing layer 8, the third packing layer 11, and the wire mesh demister 12, before exiting from the top outlet flue 2, which connects to the induced draft fan or the absorption tower.

[0017] The bottom of scrubbing tower 1 serves as the scrubbing liquid storage area. A makeup water inlet, a wastewater outlet, and a circulating liquid interface are located on the side wall of the bottom. The scrubbing liquid stored in the bottom is connected to the circulating pump 13 via a scrubbing liquid circulation pipe. After being pressurized by the pump, it is transported to the circulating liquid cooler 14. A circulating liquid flow meter 26 is installed on the circulation pipe. The circulating liquid cooler 14 is equipped with cooling water inlet and outlet pipes. The circulating liquid cooler 14 typically uses a tubular heat exchanger. The cooled circulating liquid is then transported to the spray device 10 at the top of scrubbing tower 1 and sprayed evenly into the interior of the scrubbing tower. The sprayed washing liquid flows downward through the second gas-liquid distributor 9 and is evenly distributed in the second packing layer 8, where it undergoes sufficient mass and heat transfer with the rising flue gas. A second anti-wall-adhesion flow baffle 7 is installed below the second packing layer 8 to prevent the washing liquid from adhering to the wall and flowing down. The washing liquid continues to flow downward through the first gas-liquid distributor 6 and is evenly distributed in the second packing layer 5, where it undergoes further sufficient mass and heat transfer with the rising flue gas. A second anti-wall-adhesion flow baffle 4 is installed below the second packing layer 5 to prevent the washing liquid from adhering to the wall and flowing down. The washing liquid finally flows downward to the bottom of the tower, repeating the above cycle process.

[0018] The raw flue gas undergoes mass and heat transfer through two layers of packing and washing liquid, removing small amounts of dust, gypsum, SO2, NOx and other acidic gases carried in the flue gas, while reducing the flue gas temperature. It then continues to pass through the third layer of packing 11 and wire mesh demister 12 to remove entrained liquid particles, and flows to the next process through the top outlet flue 2.

[0019] A raw flue gas pressure sensor 18 is installed on the raw flue gas duct at the inlet of scrubbing tower 1. A first layer pressure sensor 19 and a second layer pressure sensor 20 are respectively installed above each packing layer of the scrubbing tower. An outlet pressure sensor 24 is installed on the outlet flue duct 2. The gas-liquid ratio in scrubbing tower 1 can be adjusted according to the above pressure sensors.

[0020] The bottom of the washing tower 1 is equipped with a tower bottom liquid level sensor 15, a tower bottom liquid temperature sensor 16, and a pH value sensor 29. The water supply and wastewater discharge can be adjusted according to the above measuring points.

[0021] A circulating fluid flow meter 26 and a circulating fluid temperature sensor 25 are installed on the circulating fluid pipeline. The cooling water flow rate of the circulating fluid cooler 14 can be adjusted according to the above measuring points. An alkali solution filling port is provided on the pipeline before the circulating pump 13. The alkali solution filling amount can be adjusted according to the pH value sensor 27.

[0022] The raw flue gas inlet pipe is equipped with a raw flue gas temperature sensor 17, a raw flue gas pressure sensor 18, a raw flue gas CO2 analyzer 23, and a raw flue gas flow meter 24.

[0023] The scrubbing tower 1 is made of carbon steel lined with glass flakes, and its internal components are made of stainless steel.

[0024] This invention is applicable to the deep purification of flue gas in chemical absorption CO2 capture devices. It has high operational flexibility and high purification efficiency, and can be widely used in low-concentration and low-pressure CO2 capture fields such as coal-fired power plants, industrial boilers, and lime kilns. It can also be used in other industries that require deep flue gas purification.

Claims

1. A deep flue gas purification system for a CO2 capture device, characterized in that: It includes a scrubbing tower and a circulating liquid system; the scrubbing tower includes a bottom scrubbing liquid storage area, a middle flue gas scrubbing section, an upper demister section, and a top outlet flue. The middle flue gas scrubbing section is provided with a flue gas inlet at its lower part and a packing layer. The upper demister section includes a spray device, a packing layer, and a demister. The circulating liquid system includes a circulating liquid pipeline equipped with a circulating pump and a circulating liquid cooler. One end of the circulating liquid pipeline is connected to the bottom scrubbing liquid storage area, and the other end is connected to the spray device. An alkali addition port is provided on the circulating liquid pipeline.

2. A flue gas deep cleaning system for a CO2 capture plant according to claim 1, characterized in that: The packing layer of the middle flue gas scrubbing section includes a support beam, a support grid, packing, and a pressing device. A gas-liquid distributor is provided above the packing layer, and an anti-wall-adhesion flow baffle ring is provided below it.

3. A flue gas deep cleaning system for a CO2 capture plant according to claim 1, characterized in that: The upper demisting section includes a support beam, a support grid, packing material, and a pressing device, and the demister is a wire mesh demister.

4. A flue gas deep cleaning system for a CO2 capture plant according to claim 1, characterized in that: The bottom washing liquid storage area is equipped with a water inlet, a wastewater outlet, and a circulating liquid outlet, and the circulating liquid outlet is connected to one end of the circulating liquid pipeline.

5. A flue gas deep cleaning system for a CO2 capture plant according to claim 1, characterized in that: The scrubbing tower is equipped with a flue gas distributor connected to the flue gas inlet. Outside the scrubbing tower, there is a raw flue gas inlet pipe connected to the flue gas inlet. The raw flue gas inlet pipe is equipped with a raw flue gas temperature sensor, a raw flue gas pressure sensor, a raw flue gas CO2 analyzer, and a raw flue gas flow meter.

6. A flue gas deep cleaning system for a CO2 capture plant according to claim 1, characterized in that: The bottom washing liquid storage area is equipped with a tower bottom liquid level sensor, a tower bottom liquid temperature sensor, and a pH sensor; the circulating liquid pipeline is equipped with a circulating liquid temperature sensor and a circulating liquid flow meter; and the middle flue gas scrubbing section is equipped with a flue gas pressure sensor.

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