Integrated removal system and method for multiple pollutants in flue gas

Abstract

The present invention discloses a system and method for integrated removal of multiple pollutants from flue gas. After the flue gas in the boiler passes through a primary economizer, one way is connected to the flue gas inlet of the air preheater, and one way is connected to the flue gas inlet of the heating section of the regeneration tower. The flue gas outlet of the heating section of the regeneration tower is connected to the flue gas inlet pipeline of the preheating section of the regeneration tower. The flue gas outlet of the preheating section of the regeneration tower and the flue gas outlet pipeline of the air preheater are connected to the flue gas inlet of the dust collector after being combined. The flue gas outlet of the dust collector is connected to the flue gas inlet of the cooling tower, and the flue gas outlet of the cooling tower is connected to the flue gas inlet of the adsorption tower. After the cold air is pressurized by a blower, one way is connected to the air inlet of the air preheater, and one way is connected to the air inlet of the cooling section of the regeneration tower. The air outlet of the cooling section of the regeneration tower is connected to the air outlet of the air preheater. The present invention can implement integrated treatment of multiple pollutants on flue gas, and make full use of the flue gas at the tail of the boiler to regenerate the adsorbent, thereby reducing the operating cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas pollutant treatment and purification, and specifically relates to a system and method for integrated removal of multiple pollutants from flue gas. Background Art

[0002] The large amount of pollutants produced by coal-fired flue gas is one of the important factors that endanger the atmospheric environment and human health. Therefore, the research and development of high-efficiency, low-energy consumption, multi-pollutant joint control technology is the foothold and primary task for the clean and efficient use of coal.

[0003] At present, the technical route for pollutant removal from coal-fired units is mostly based on the transformation and upgrading of traditional desulfurization and denitrification technologies. Although it basically meets the current environmental protection needs, it also brings many problems such as desulfurization wastewater treatment, denitrification catalyst failure, excessive limestone mining, secondary pollution from ammonia escape, complicated process flow, and high operating costs. Limited by the process principles, the removal efficiency of the current mainstream desulfurization and denitrification technologies is difficult to further improve on the basis of the current ultra-low emissions and achieve near-zero emissions of pollutants. In addition, with the increasingly stringent environmental protection requirements, pollutants such as sulfur trioxide, heavy metals, and volatile organic compounds (VOCs) in flue gas are expected to be gradually included in the flue gas pollutant emission control system, and the current technology has limited ability to remove such pollutants.

[0004] In similar flue gas activated coke combined desulfurization and denitrification processes, the activated coke regeneration system mostly utilizes electric heaters or hot air furnaces, consuming electricity or coal gas as heat sources, which increases equipment investment, makes the system complex and improves the operating cost of the entire device. Summary of the invention

[0005] In order to overcome the defects of the prior art, the present invention provides a system and method for integrated removal of multiple pollutants from flue gas.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A flue gas multi-pollutant integrated removal system comprises a boiler, an air preheater, a dust collector, a cooling tower, an adsorption tower and a regeneration tower, wherein the regeneration tower comprises a regeneration tower preheating section, a regeneration tower heating section and a regeneration tower cooling section arranged in sequence from top to bottom; a primary economizer is arranged in the flue of the boiler, the flue outlet is respectively connected to the flue gas inlet of the air preheater and the flue gas inlet of the regeneration tower heating section, the flue gas outlet of the regeneration tower heating section is connected to the flue gas inlet of the regeneration tower preheating section, the flue gas outlet of the regeneration tower preheating section is connected to the flue gas outlet of the air preheater after merging with the flue gas outlet of the air preheater A dust collector, wherein the flue gas outlet of the dust collector is connected to the flue gas inlet of the cooling tower, the flue gas outlet of the cooling tower is connected to the flue gas inlet of the adsorption tower, the clean flue gas coming out of the flue gas outlet of the adsorption tower is connected to the chimney for discharge, the adsorbent outlet at the bottom of the adsorption tower is connected to the adsorbent inlet of the regeneration tower, and the adsorbent outlet of the regeneration tower is connected to the adsorbent inlet of the adsorption tower; and also includes a blower, through which cold air is respectively connected to the air inlet of the cooling section of the regeneration tower and the air inlet of the air preheater, and the air outlet of the cooling section of the regeneration tower and the air outlet of the air preheater are connected to the boiler after merging.

[0008] Furthermore, a main flue damper valve is provided between the flue outlet of the boiler and the flue gas inlet of the air preheater.

[0009] Furthermore, a regeneration flue gas regulating valve is provided between the flue outlet of the boiler and the flue gas inlet of the heating section of the regeneration tower.

[0010] Furthermore, a regeneration air regulating valve is provided between the outlet of the blower and the air inlet of the cooling section of the regeneration tower.

[0011] Furthermore, a main air damper valve is provided between the outlet of the blower and the air inlet of the air preheater.

[0012] Furthermore, the regeneration tower preheating section, regeneration tower heating section and regeneration tower cooling section are split structures, and a first cavity for connecting the regeneration tower preheating section pipe line and the regeneration tower heating section pipe line is provided between the regeneration tower preheating section and the regeneration tower heating section, and a second cavity for connecting the regeneration tower heating section pipe line and the regeneration tower cooling section pipe line is provided between the regeneration tower heating section and the regeneration tower cooling section.

[0013] Furthermore, nitrogen interfaces are provided on the side walls of the first cavity and the second cavity.

[0014] The invention discloses an integrated method for removing multiple pollutants from flue gas. The flue gas generated in the furnace of the boiler is cooled by a primary economizer and then divided into two paths. One path is connected to the flue gas inlet of the air preheater, and the other path is connected to the flue gas inlet of the heating section of the regeneration tower. The flue gas outlet pipe of the heating section of the regeneration tower is connected to the flue gas inlet pipe of the preheating section of the regeneration tower, and the flue gas outlet pipe of the preheating section of the regeneration tower is connected to the flue gas outlet pipe of the air preheater. The two cooled flue gases are collected and dust is removed. The dust-removed flue gas enters a cooling tower for cooling. The cooled flue gas enters an adsorption tower for adsorption removal. The clean flue gas from the flue gas outlet of the adsorption tower is discharged to a chimney. The adsorbent of the adsorption tower enters the regeneration tower for regeneration and then returns to the adsorption tower. In addition, the cold air from the atmospheric environment is pressurized by a blower and divided into two paths. One path is connected to the air inlet of the air preheater, and the other path is connected to the air inlet of the cooling section of the regeneration tower. The air outlet of the cooling section of the regeneration tower is connected to the hot air outlet pipeline of the air preheater. The two air flows are combined and used in the boiler.

[0015] Furthermore, a main flue damper valve is arranged between the flue outlet of the boiler and the flue gas inlet of the air preheater, a regeneration flue gas regulating valve is arranged between the flue outlet of the boiler and the flue gas inlet of the regeneration tower heating section, a regeneration air regulating valve is arranged between the outlet of the blower and the air inlet of the regeneration tower cooling section, a main air damper valve is arranged between the outlet of the blower and the air inlet of the air preheater, the amount of regeneration flue gas going to the regeneration tower heating section is regulated by the main flue damper valve and the regeneration flue gas regulating valve; the amount of cooling air going to the regeneration tower cooling section is regulated by the main air damper valve and the regeneration air regulating valve.

[0016] Furthermore, during use, the regeneration tower heating section and the regeneration tower preheating section periodically use compressed air for backblowing and dust removal.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] The present invention is suitable for treating flue gas pollutants from coal-fired power plants and the like. The flue gas from the first-level economizer of the boiler is divided into two paths, one path enters the air preheater to heat the air, and the other path goes to the heating section of the regeneration tower for heating and regenerating the adsorbent. Since the flue gas temperature here is above 350°C, which is just in the ideal regeneration temperature range of the adsorbent, the present invention successively adopts dust removal, cooling and adsorption purification processes to implement multi-pollutant integrated treatment of the flue gas, and fully utilizes the flue gas at the tail end of the boiler to regenerate the adsorbent. There is no need to additionally set up electric heaters or hot air furnaces and other equipment, thereby reducing the power consumption of the plant or the use of coal gas. The system is simple and the operating cost is low. The cold air in the atmospheric environment is also divided into two paths after being pressurized by the blower, one path directly goes to the air preheater to absorb the heat of the flue gas, and the other path enters the cooling section of the regeneration tower for cooling the adsorbent and absorbing the heat of the adsorbent at the same time. The hot air coming out of the cooling section of the regeneration tower is combined with the hot air coming out of the air preheater into one path and then goes to the boiler for use.

[0019] Furthermore, the flue gas from the air preheater is combined with the flue gas from the preheating section of the regeneration tower and then enters the dust collector for dust removal. The dust-removed flue gas enters the cooling tower for deep cooling and then enters the adsorption tower for purification. The clean flue gas is sent to the chimney for discharge.

[0020] Furthermore, different sections of the regeneration tower are not directly connected but disconnected and provided with nitrogen interfaces. When necessary, nitrogen is introduced into the adsorbent bed for protection to avoid oxygen leakage and bed temperature runaway causing accidents.

[0021] Furthermore, the amount of regeneration flue gas required for the heating section of the regeneration tower is regulated by the main flue damper valve and the regeneration flue gas regulating valve; the amount of cooling air required for the cooling section of the regeneration tower is regulated by the main air damper valve and the regeneration air regulating valve.

[0022] In addition, the heating section and preheating section of the regeneration tower can be back-blown with compressed air regularly to avoid dust accumulation on the heat exchange surface and affect the regeneration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 This is a schematic diagram of an integrated flue gas multi-pollutant removal system of the present invention.

[0025] Among them, 1. Boiler; 2. First-stage economizer; 3. Air preheater; 4. Regeneration tower; 5. Main flue damper valve; 6. Regeneration tower preheating section; 7. Blower; 8. Main air damper valve; 9. Regeneration air regulating valve; 10. Regeneration flue gas regulating valve; 11. Regeneration tower heating section; 12. Regeneration tower cooling section; 13. Dust collector; 14. Cooling tower; 15. Adsorption tower. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in further detail below:

[0027] like Figure 1 As shown, a flue gas multi-pollutant integrated removal system includes a boiler 1, a primary economizer 2, an air preheater 3, a regeneration tower 4, a main flue damper valve 5, a regeneration tower preheating section 6, a blower 7, a main air damper valve 8, a regeneration air regulating valve 9, a regeneration flue gas regulating valve 10, a regeneration tower heating section 11, a regeneration tower cooling section 12, a dust collector 13, a cooling tower 14, and an adsorption tower 15.

[0028] The flue gas generated in the furnace of the boiler 1 is cooled by the primary economizer 2 and then divided into two paths. One path is connected to the flue gas inlet of the air preheater 3 through the main flue damper valve 5, and the other path is connected to the flue gas inlet of the regeneration tower heating section 11 through the regeneration flue gas regulating valve 10. The flue gas outlet pipe of the regeneration tower heating section 11 is connected to the flue gas inlet of the regeneration tower preheating section 6. The flue gas outlet pipe of the regeneration tower preheating section 6 is connected to the flue gas outlet of the air preheater 3. The two cooled flue gases are collected and connected to the flue gas inlet of the dust collector 13. The flue gas outlet of the dust collector 13 is connected to the flue gas inlet of the cooling tower 14. The flue gas outlet of the cooling tower 14 is connected to the flue gas inlet of the adsorption tower 15. The clean flue gas coming out of the flue gas outlet of the adsorption tower 15 is sent to the chimney for discharge.

[0029] The adsorbent outlet at the bottom of the adsorption tower 15 is connected to the adsorbent inlet of the regeneration tower 4 , and the adsorbent outlet at the bottom of the regeneration tower 4 is connected to the adsorbent inlet at the top of the adsorption tower 15 , thereby forming a circulating movement of the adsorbent.

[0030] The regeneration tower 4 adopts an indirect heat exchange method, the adsorbent moves in the tube side at a certain flow rate, and the corresponding heat exchange flue gas or air flows in the shell side. The regeneration tower preheating section 6, the regeneration tower heating section 11 and the regeneration tower cooling section 12 are disconnected, and a protective nitrogen interface is provided.

[0031] The regeneration tower heating section 11 and the regeneration tower preheating section 6 can be back-blown and deashed regularly using compressed air;

[0032] The cold air from the atmospheric environment is pressurized by the blower 7 and divided into two paths. One path is connected to the air inlet of the air preheater 3 through the main air damper valve 8, and the other path is connected to the air inlet of the regeneration tower cooling section 12 through the regeneration air regulating valve 9. The air outlet of the regeneration tower cooling section 12 is connected to the hot air outlet pipeline of the air preheater 3. The two air streams are combined and sent to the boiler for use.

[0033] The amount of regeneration flue gas required by the regeneration tower heating section 11 is regulated by the main flue damper valve 5 and the regeneration flue gas regulating valve 10; the amount of cooling air required by the regeneration tower cooling section 12 is regulated by the main air damper valve 8 and the regeneration air regulating valve 9.

[0034] The present invention can remove multiple pollutants such as SOx, NOx, HCl, heavy metals and VOCs in an integrated manner, and can achieve near-zero emissions; the operating cost is low, no limestone, ammonia and other material consumption is required, and flue gas water recovery and pollutant resource utilization can be achieved; the secondary pollutant emissions are small, no desulfurization wastewater is generated, and there are no problems such as catalyst solid waste and ammonia escape; this technology is currently the most comprehensive near-zero emission technology for integrated removal, and can be widely used in flue gas treatment in coal-fired power plants, as well as in places where pollutants are difficult to effectively treat, such as garbage incineration and industrial furnaces.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated flue gas multi-pollutant removal system, characterized in that: The invention comprises a boiler (1), an air preheater (3), a dust collector (13), a cooling tower (14), an adsorption tower (15) and a regeneration tower (4), wherein the regeneration tower (4) comprises a regeneration tower preheating section (6), a regeneration tower heating section (11) and a regeneration tower cooling section (12) which are arranged in sequence from top to bottom; a primary economizer (2) is arranged in the flue of the boiler (1), the flue outlet is respectively connected to the flue gas inlet of the air preheater (3) and the flue gas inlet of the regeneration tower heating section (11), the flue gas outlet of the regeneration tower heating section (11) is connected to the flue gas inlet of the regeneration tower preheating section (6), the flue gas outlet of the regeneration tower preheating section (6) is connected to the dust collector (13) after merging with the flue gas outlet of the air preheater (3), The flue gas outlet of the dust collector (13) is connected to the flue gas inlet of the cooling tower (14), the flue gas outlet of the cooling tower (14) is connected to the flue gas inlet of the adsorption tower (15), the clean flue gas from the flue gas outlet of the adsorption tower (15) is connected to the chimney for discharge, the adsorbent outlet at the bottom of the adsorption tower (15) is connected to the adsorbent inlet of the regeneration tower (4), and the adsorbent outlet of the regeneration tower (4) is connected to the adsorbent inlet of the adsorption tower (15); and the air blower (7) is further included, and cold air is connected to the air inlet of the cooling section (12) of the regeneration tower and the air inlet of the air preheater (3) respectively through the blower (7), and the air outlet of the cooling section (12) of the regeneration tower and the air outlet of the air preheater (3) are connected to the boiler (1) after merging. A regeneration air regulating valve (9) is provided between the outlet of the blower (7) and the air inlet of the cooling section (12) of the regeneration tower; The regeneration tower preheating section (6), the regeneration tower heating section (11) and the regeneration tower cooling section (12) are of split structure, and a first cavity for connecting the regeneration tower preheating section pipe line and the regeneration tower heating section pipe line is provided between the regeneration tower preheating section (6) and the regeneration tower heating section (11), and a second cavity for connecting the regeneration tower heating section pipe line and the regeneration tower cooling section pipe line is provided between the regeneration tower heating section (11) and the regeneration tower cooling section (12).

2. The integrated flue gas multi-pollutant removal system according to claim 1 is characterized in that: A main flue damper valve (5) is provided between the flue outlet of the boiler (1) and the flue gas inlet of the air preheater (3).

3. The integrated flue gas multi-pollutant removal system according to claim 1 is characterized in that: A regeneration flue gas regulating valve (10) is provided between the flue outlet of the boiler (1) and the flue gas inlet of the regeneration tower heating section (11).

4. The integrated flue gas multi-pollutant removal system according to claim 1 is characterized in that: A main air damper valve (8) is provided between the outlet of the blower (7) and the air inlet of the air preheater (3).

5. The integrated flue gas multi-pollutant removal system according to claim 1 is characterized in that: Nitrogen interfaces are provided on the side walls of the first cavity and the second cavity.

6. A method for integrated removal of multiple pollutants from flue gas, using the integrated removal system for multiple pollutants from flue gas according to claim 1, characterized in that: The flue gas generated in the furnace of the boiler (1) is cooled by the primary economizer (2) and then divided into two paths, one of which is connected to the flue gas inlet of the air preheater (3) and the other is connected to the flue gas inlet of the heating section (11) of the regeneration tower. The flue gas outlet pipe of the heating section (11) of the regeneration tower is connected to the flue gas inlet pipe of the preheating section (6) of the regeneration tower, and the flue gas outlet pipe of the preheating section (6) of the regeneration tower is connected to the flue gas outlet pipe of the air preheater (3). The two cooled flue gases are collected and dust is removed. The dust-removed flue gas enters the cooling tower (14) for cooling. The cooled flue gas enters The adsorption tower (15) performs adsorption removal, and the clean flue gas from the flue gas outlet of the adsorption tower (15) is discharged to the chimney. The adsorbent of the adsorption tower (15) enters the regeneration tower (4) for regeneration and then returns to the adsorption tower (15). In addition, the cold air from the atmospheric environment is pressurized by the blower (7) and divided into two paths, one of which is connected to the air inlet of the air preheater (3) and the other is connected to the air inlet of the regeneration tower cooling section (12). The air outlet of the regeneration tower cooling section (12) is connected to the hot air outlet pipeline of the air preheater (3). The two air streams are combined and sent to the boiler for use.

7. The method for integrated removal of multiple pollutants from flue gas according to claim 6, characterized in that: A main flue damper valve (5) is provided between the flue outlet of the boiler (1) and the flue gas inlet of the air preheater (3); a regeneration flue gas regulating valve (10) is provided between the flue outlet of the boiler (1) and the flue gas inlet of the regeneration tower heating section (11); a regeneration air regulating valve (9) is provided between the outlet of the blower (7) and the air inlet of the regeneration tower cooling section (12); a main air damper valve (8) is provided between the outlet of the blower (7) and the air inlet of the air preheater (3); the amount of regeneration flue gas going to the regeneration tower heating section (11) is coordinated and adjusted by the main flue damper valve (5) and the regeneration flue gas regulating valve (10); and the amount of cooling air going to the regeneration tower cooling section (12) is coordinated and adjusted by the main air damper valve (8) and the regeneration air regulating valve (9).

8. The method for integrated removal of multiple pollutants from flue gas according to claim 6, characterized in that: During use, the regeneration tower heating section (11) and the regeneration tower preheating section (6) are regularly back-blown with compressed air to remove dust.

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