CN205208595U - Coal -fired many pollutants of flue gas concurrent processing system - Google Patents

Abstract

The utility model discloses a multi-pollutant cooperative treatment system for coal-fired flue gas, which includes a low-nitrogen burner, a mercury removal adsorbent injection system, a sulfur trioxide removal system, a desulfurization, denitrification and dust removal system, and an outlet smoke The absorption tower connected with the channel, the fuel is burned by the low-nitrogen burner, and then demercurized by the mercury removal sorbent injection system, and then the sulfur trioxide is removed by the sulfur trioxide removal system, and then enters the desulfurization, denitrification and dust removal system for treatment, and then enters the absorption tower; organic and reasonable combination, comprehensive and integrated design, and highly integrated treatment of each unit process and device for desulfurization, denitrification, dust removal, and mercury removal to achieve ultra-clean emissions of various pollutants and minimize flue gas excess The emission concentration of various pollutants is greatly reduced, which greatly reduces the investment and floor area, and also effectively reduces the flue gas flow resistance of the equipment, saving a lot of operating costs.

Description

Coal-fired flue gas multi-pollutant collaborative treatment system

technical field

The utility model relates to the field of flue gas treatment, in particular to a coal-fired flue gas multi-pollutant collaborative treatment system.

Background technique

Acid rain and the greenhouse effect are global environmental problems facing mankind today. The pollution of sulfur dioxide SO2 and nitrogen oxide NOX produced by coal burning is the main protozoa of acid rain, and the produced carbon dioxide CO2 is the main greenhouse gas, of which CO2 emissions account for about 30% of the total CO2 emissions caused by human activities . my country's energy structure is dominated by coal, and the control of coal-fired flue gas pollution is a requirement for achieving coordinated development of the economy, society, and environment, and is also a requirement for taking advantage of my country's coal reserves and realizing sustainable development of society itself. At present, most of the control technologies for coal-fired flue gas pollution, such as desulfurization, denitrification, dust removal and decarbonization, are developed independently, forming their own independent technical equipment and process flow. Coal-fired power plants at home and abroad need at least two sets of independent desulfurization, denitrification and dust removal equipment in order to meet the requirements of environmental protection emissions and eliminate SO2, NOX and dust in the flue gas. In the face of the intensification of the global greenhouse effect, coal-fired power plants at home and abroad have to study the decarbonization technology of coal-fired flue gas, and some large enterprises are even building independent power plant decarbonization projects. In order to solve the existing problems of coal-fired flue gas pollutant dispersion and removal technology, Chinese utility model patent specifications with publication numbers CN2712446Y and CN274697IY proposed a "flue gas desulfurization and denitrification device" and a "desulfurization and denitrification integrated flue gas Gas purification tower", but its desulfurization and denitrification equipment are all bulky packing devices, and ammonia solution is directly used to absorb NOX in the flue gas, not only the resistance of the entire desulfurization and denitrification equipment is greatly increased, but also cannot effectively remove NOX, because more than 90% of the NOX component is nitric oxide NO, and NO is difficult to dissolve in water, so it is difficult to absorb NO by simple washing method. The Chinese Invention Patent Application Publication No. CN1559654A introduces a "desulfurization, dust removal, denitrification, defluorination wet flue gas purification unit and its purification method", which uses lye and flue gas to mix the flue gas to remove A variety of pollutants, but the unit and the purification method will produce a large amount of wastewater, not only the wastewater needs to be retreated, but also the removal efficiency of the technical solution for NOX is too low, and the anti-corrosion requirements for the equipment are also extremely high, resulting in The process is complicated and the operating cost is increased. The existing single pollutant control system is just a simple combination, high cost, serious waste of resources, and it is difficult to achieve ultra-clean discharge of multiple pollutants, especially for sulfur trioxide, the existence of which can cause SCR to retreat at low load , causing nitrogen oxide emissions to exceed the standard, and even severely corrode the rear equipment. Therefore, it is urgent to develop a coal-fired flue gas ultra-clean emission technology system with reasonable cost, reliable operation and low energy consumption.

Utility model content

In view of this, the purpose of this utility model is to provide a multi-pollutant cooperative treatment system for coal-fired flue gas, which can realize the ultra-clean discharge of various pollutants and reduce the emission concentration of various pollutants in the flue gas to the greatest extent.

The coal-fired flue gas multi-pollutant cooperative treatment system of the present invention includes a low-nitrogen burner, a mercury removal adsorbent injection system, a sulfur trioxide removal system, a desulfurization, denitrification and dust removal system, and a flue connected to the outlet flue of the desulfurization, denitrification and dust removal system. Absorption tower, after the fuel is burned by a low-nitrogen burner, it is demercurized by a mercury removal sorbent injection system, and then sulfur trioxide is removed by a sulfur trioxide removal system, and then enters a desulfurization, denitrification and dust removal system for treatment, and then enters an absorption tower;

Further, the desulfurization, denitrification and dust removal system includes SCR denitrification device, low and low temperature electric dust collector, boiling foam desulfurization and dust removal absorption tower and wet electric dust collector, and the flue gas treated by the sulfur trioxide removal system is processed by the low and low temperature electric dust collector After the primary dust removal, it enters the boiling foam desulfurization dust removal absorption tower for secondary dust removal and desulfurization treatment, and then performs the third stage dust removal and removes the sulfuric acid droplets in the flue gas through the wet electrostatic precipitator;

Further, the inlet flue of the low and low temperature electrostatic precipitator is provided with a waste heat recovery system;

Further, the waste heat recovery system is a Teflon plastic heat exchanger;

Further, the boiling foam desulfurization and dedusting absorption tower is equipped with boiling foam mass transfer components, wall rings, slurry spray layers and honeycomb centrifugal demisters;

Further, the boiling foam mass transfer member is provided with two layers, the distance between the first layer of foam member and the top elevation of the flue inlet is not less than 1m, and the distance between the second layer of foam member and the first spray layer is not less than 1.5m, and the distance between the two foam members is not less than 1m. The spacing between layers of foam components is not less than 2m;

Further, the wall ring is provided with 1 to 3 layers, the width of the wall ring is not less than 200 mm, and the slurry spray layer is 3 to 5 layers with cross-dislocation distribution;

Further, the honeycomb centrifugal demister is provided with 1 to 2 layers, the centrifugal deflection angle of the demister blades is 30°, the upper and lower sides of each layer of demister are respectively provided with flushing water, and the droplet concentration at the outlet of the demister is less than 20 mg/Nm ³ , the total pressure resistance is less than 350Pa;

Further, the wet electrostatic precipitator is tube type or plate type, and the flue gas inlet channel and outlet channel of the wet electrostatic precipitator are provided with an air flow uniform distribution device;

Further, the power supply of the wet electrostatic precipitator adopts a constant current high-voltage power supply, the cathode line adopts acupuncture type, the flushing water system adopts an indirect flushing method, and the flushing time interval is 24 hours.

Beneficial effects of the utility model: the coal-fired flue gas multi-pollutant synergistic treatment system of the utility model organically and rationally combines the unit processes and devices of flue gas desulfurization, denitrification, dust removal and mercury removal at the tail of traditional coal-fired boilers, The comprehensive and integrated design and highly integrated treatment realize the ultra-clean emission of various pollutants, minimize the emission concentration of various pollutants in the flue gas, and save the huge flue gas required for the independent operation of each unit process and device. The pipe connection system and the corresponding flue gas collection and diffusion distribution facilities greatly reduce the investment and floor space, and also effectively reduce the flue gas flow resistance of the equipment, saving a lot of operating costs.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

Fig. 1 is the structural representation of the utility model.

detailed description

Figure 1 is a schematic structural view of the utility model, as shown in the figure: the multi-pollutant co-processing system for coal-fired flue gas in this embodiment includes a low-nitrogen burner 1, a mercury removal sorbent injection system 2, and a sulfur trioxide removal system. System 3, the desulfurization, denitrification and dust removal system and the absorption tower 9 connected with the outlet flue of the desulfurization, denitrification and dust removal system. The removal system 2 removes sulfur trioxide and enters the desulfurization, denitrification and dust removal system for treatment and then enters the absorption tower 9; the low-nitrogen burner 1 reduces the generation of _NOx , and the mercury removal sorbent injection system 2 is used for the initial mercury removal of fuel flue gas. The desulfurization, denitrification and dust removal system is used to realize the coordinated treatment of pollutants such as SO _{2 ,} SO _{3 ,} dust (including PM10, PM2.5 and below particulate pollutants), mercury, etc., and finally realize the ultra-clean emission of various pollutants, minimizing the The emission concentration of various pollutants in the flue gas; the sulfur trioxide removal system 3 removes sulfur trioxide to solve the reaction of NH ₃ and SO ₃ to generate ammonium bisulfate, which deposits on the surface of the catalyst, blocks the pores of the catalyst, and removes the low catalyst The activity and life of the denitrification system caused the problem that the denitrification system needs to stop the ammonia spraying and exit the operation when the load is low, and the low-temperature catalyst cannot be used in the subsequent process; at the same time, it solves the problem of blockage caused by the viscosity of ammonium bisulfate caused by a large amount of fly ash deposited on the surface of the equipment, And then cause the safety operation problem caused by the short circuit of the equipment.

In this embodiment, the desulfurization, denitrification and dust removal system includes an SCR denitrification device 4, a low and low temperature electrostatic precipitator 6, a boiling foam desulfurization and dust removal absorption tower 7 and a wet electrostatic precipitator 8, and the absorption tower 9 and the wet electrostatic precipitator 8 The flue gas at the exit of the outlet is connected. The flue gas treated by the sulfur trioxide removal system is subjected to primary dust removal by the low and low temperature electrostatic precipitator 6, and then enters the boiling foam desulfurization and dust removal absorption tower 7 for secondary dust removal and desulfurization treatment, and then passes through the wet type The electrostatic precipitator 8 and the absorption tower 9 perform three-stage dust removal and remove sulfuric acid droplets in the flue gas; avoid the reaction of NH ₃ and SO ₃ to form ammonium bisulfate, which is deposited on the surface of the catalyst to ensure the activity and life of the catalyst , to ensure the normal operation of SCR, low and low temperature electrostatic precipitator 6, boiling foam desulfurization dust removal absorption tower 7, wet electrostatic precipitator 8 and air precipitator, and at the same time avoid the failure of wet electrostatic precipitator 8 (such as electrostatic precipitator paste Board, electric bag composite dust collector paste bag, etc.). There will be no corrosion, blockage, "blue feather" and other problems in each equipment, ensuring the safe operation of each equipment of the unit and avoiding environmental pollution problems. The inlet flue gas temperature of low and low temperature electrostatic precipitator is 85~95℃, and the flue gas specific resistance is 10 ¹⁰ ~10 ¹¹ Ω·cm.

In this embodiment, the inlet flue of the low and low temperature electrostatic precipitator is provided with a waste heat recovery system 5 to ensure the normal operation of the low and low temperature electrostatic precipitator.

In this embodiment, the waste heat recovery system 5 is a Teflon plastic heat exchanger; it has strong corrosion resistance and large heat exchange capacity, and can deeply recover the waste heat data of the flue gas to reduce the temperature of the flue gas, so that SO3 condenses on the surface of the flue dust and enters the It is removed after electrostatic precipitator to improve the removal rate of SO3.

In this embodiment, the boiling foam desulfurization and dust removal absorption tower 7 is provided with a boiling foam mass transfer member, a wall ring, a slurry spray layer and a honeycomb centrifugal demister; the foam mass transfer member, wall ring, slurry spray The shower layer and the honeycomb centrifugal demister are existing structures, and will not be described here one by one.

In this embodiment, the boiling foam mass transfer member is provided with two layers, the first layer of foam member is not less than 1m away from the top of the flue inlet, and the second layer of foam member is not less than 1.5m away from the first layer of spray layer. m, the distance between the two layers of foam components is not less than 2m; the opening ratio of the foam components of the lower layer is greater than that of the foam components of the upper layer.

In this embodiment, the wall ring is provided with 1 to 3 layers, and the width of the wall ring is not less than 200 mm, and the slurry spray layer is 3 to 5 layers with cross-dislocation distribution; the honeycomb centrifugal demister is set 1-2 floors, the centrifugal deflection angle of the mist eliminator blades is 30°, the upper and lower sides of each layer of mist eliminators are respectively provided with flushing water, the concentration of mist droplets at the outlet of the mist eliminator is less than 20mg/Nm ³ , and the total pressure resistance is less than 350Pa; The location distribution of quality components, wall rings, slurry spray layers and honeycomb centrifugal demisters improves the flue gas treatment effect and improves the desulfurization and dust removal efficiency.

In this embodiment, the wet electrostatic precipitator 8 is tube type or plate type, and the flue gas inlet channel and outlet channel of the wet electrostatic precipitator are provided with an air flow uniform distribution device;

In this embodiment, the power supply of the wet electrostatic precipitator 8 adopts a constant current high-voltage power supply, the cathode line adopts acupuncture type, the flushing water system adopts an indirect flushing method, and the flushing time interval is 24 hours.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present utility model without limitation. Although the utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the utility model can be Modifications or equivalent replacements of the technical solutions without departing from the purpose and scope of the technical solutions of the utility model shall be covered by the claims of the utility model.

Claims (10)

1. A multi-pollutant co-processing system for coal-fired flue gas, characterized in that it includes a low-nitrogen burner, a mercury removal sorbent injection system, a sulfur trioxide removal system, a desulfurization, denitrification and dust removal system, and an outlet of the desulfurization, denitrification and dust removal system The absorption tower connected by the flue, the fuel is burned by the low-nitrogen burner and then demercurized by the demercury sorbent injection system, and then the sulfur trioxide is removed by the sulfur trioxide removal system and then enters the desulfurization, denitrification and dust removal system for treatment. absorption tower. 2. The coal-fired flue gas multi-pollutant co-processing system according to claim 1, characterized in that: the desulfurization, denitrification and dust removal system includes SCR denitrification device, low and low temperature electrostatic precipitator, boiling foam desulfurization and dust removal absorption tower and wet type Electrostatic precipitator, the absorption tower is connected to the outlet flue of the wet electrostatic precipitator, and the flue gas treated by the sulfur trioxide removal system is subjected to first-level dust removal by the low-temperature electric precipitator and then enters the boiling foam desulfurization and dust removal absorption tower The secondary dust removal and desulfurization treatment is carried out, and then the wet electrostatic precipitator is used for the third stage dust removal and the sulfuric acid mist in the flue gas is removed. 3. The coal-fired flue gas multi-pollutant cooperative treatment system according to claim 2, characterized in that: the inlet flue of the low-low temperature electrostatic precipitator is provided with a waste heat recovery system. 4. The coal-fired flue gas multi-pollutant co-processing system according to claim 3, characterized in that: the waste heat recovery system is a Teflon plastic heat exchanger. 5. The coal-fired flue gas multi-pollutant cooperative treatment system according to claim 2, characterized in that: the boiling foam desulfurization and dust removal absorption tower is equipped with boiling foam mass transfer components, wall rings, and slurry spray layers And honeycomb centrifugal demister. 6. The coal-fired flue gas multi-pollutant synergistic treatment system according to claim 5, characterized in that: the boiling foam mass transfer member is provided with two layers, and the first layer of foam member is no higher than the top level of the flue inlet. Less than 1m, the distance between the second layer of foam components and the first spray layer is not less than 1.5m, and the distance between the two layers of foam components is not less than 2m. 7. The coal-fired flue gas multi-pollutant cooperative treatment system according to claim 5, characterized in that: the wall ring is provided with 1 to 3 layers, the width of the wall ring is not less than 200mm, and the slurry spray layer It is 3 to 5 layers with cross dislocation distribution. 8. The coal-fired flue gas multi-pollutant cooperative treatment system according to claim 5, characterized in that: the honeycomb centrifugal demister is provided with 1 to 2 layers, and the centrifugal deflection angle of the demister blades is 30°. The upper and lower layers of the demister are respectively provided with flushing water, the concentration of mist at the outlet of the demister is less than 20mg/Nm ³ , and the total pressure resistance is less than 350Pa. 9. The coal-fired flue gas multi-pollutant co-processing system according to claim 2, characterized in that: the wet electrostatic precipitator is a tube type or a plate type, and the flue gas inlet channel and outlet channel of the wet electrostatic precipitator Set up the air distribution device. 10. The coal-fired flue gas multi-pollutant cooperative treatment system according to claim 9, characterized in that: the power supply of the wet electrostatic precipitator adopts a constant current high-voltage power supply, the cathode line adopts an acupuncture type, and the flushing water system adopts an indirect Flushing method, the flushing time interval is 24h.