CN204891590U - Energy -efficient deNOx systems of domestic waste power plant - Google Patents

Abstract

A high-efficiency and energy-saving denitrification system for a domestic waste power plant relates to the technical field of design of the domestic waste denitrification system. The utility model includes grate furnace, waste heat boiler, deacidification reaction tower, bag dust collector, ash bin, low temperature SCR reactor, induced draft fan, chimney, SNCR spray gun, first air compressor, soft water tank, SNCR ammonia water buffer tank, The first ammonia water delivery pump, the ammonia water storage tank, the second ammonia water delivery pump, the SCR ammonia water buffer tank, the ammonia evaporator, the mixer, and the second air compressor; the utility model adopts the "SNCR+low temperature SCR" combination out of stock, saving investment costs, It saves the heat energy of the power plant, prolongs the service life of the catalyst, and has certain economic efficiency; it meets the emission standard and has high efficiency.

Description

A high-efficiency and energy-saving denitrification system for domestic waste power plants

technical field

The utility model relates to the technical field of design of a domestic garbage denitrification system.

Background technique

The number of new waste incineration power plants in my country is increasing year by year, and the proportion of incineration in domestic waste disposal is also increasing year by year. Domestic waste incineration plants, like coal-fired power plants, will produce a large amount of air pollutants such as particulate matter, HCl, SO2, NOX, and dioxins during the incineration process. At present, the flue gas treatment method of domestic waste power plants is "semi-dry method/dry method deacidification + bag filter", which effectively controls smoke dust, particulate matter and soluble acid gas. However, NOX in the flue gas is not easily soluble in water, and the deacidification reaction tower cannot effectively remove it. Domestic waste incineration plants that have been built and operated in China implement the "Standards for Pollution Control of Domestic Waste Incineration" (GB18485-2014), and the NOX emission limit is 250mg/Nm3. Therefore, domestic waste incineration plants must implement feasible NOX control measures .

In the denitrification process of domestic waste power plants, SNCR and SCR are conventional treatment processes. Using the SNCR system alone has been difficult to meet the air pollutant emission standards required by environmental protection. In addition, SNCR has certain disadvantages: the reaction temperature is generally 850-1100°C. When the reaction temperature is too high, the decomposition of ammonia will reduce the NOX reduction rate. When the reaction temperature is too low, the escape of ammonia will increase, which will also reduce the NOX reduction rate. NH3 is a highly volatile and toxic substance, and the escape of ammonia will cause new environmental pollution; using the SCR system alone can make the NOX emission meet the standard. The reaction principle of SCR technology is that under the action of a catalyst, the reducing agent containing amino groups will selectively reduce NOX in the flue gas in the incinerator to N2 at a temperature between 250 and 450 °C. SCR layouts are generally divided into three layouts: high temperature and high dust, high temperature and low dust, and low temperature and low dust. The high-temperature and high-dust layout is adopted, and the SCR reactor is arranged between the economizer and the air preheater, which is mostly used in coal-fired power plants; the high-temperature and low-dust layout, the SCR reactor is arranged after the dust collector, because the dust collector needs The high-temperature dust collector is used, which is expensive, so it is rarely used in engineering; the low-temperature and low-dust arrangement, the SCR reactor is arranged after the desulfurization and dust removal device. The flue gas produced by domestic waste incinerators has higher heavy metal content and larger dust, which is more likely to cause catalyst poisoning than thermal power plants, greatly weakening catalyst activity and increasing operating costs. Low-temperature and low-dust methods are mostly feasible in domestic waste power plant engineering, but usually using a heat source to reheat the flue gas is very expensive to operate.

Utility model content

The purpose of the utility model is to solve the above problems and provide a cost-saving and high-efficiency denitrification system for domestic waste power plants with high efficiency and energy saving.

The utility model includes grate furnace, waste heat boiler, deacidification reaction tower, bag dust collector, ash bin, low temperature SCR reactor, induced draft fan, chimney, SNCR spray gun, first air compressor, soft water tank, SNCR ammonia water buffer tank, First ammonia delivery pump, ammonia storage tank, second ammonia delivery pump, SCR ammonia buffer tank, ammonia evaporator, mixer, second air compressor;

The exhaust port of the grate furnace is connected to the input end of the waste heat boiler, the output end of the waste heat boiler is connected to the input end of the deacidification reaction tower, the output end of the deacidification reaction tower is connected to the input end of the bag filter connected, the output end of the bag filter is connected to the input end of the low-temperature SCR reactor, the output end of the low-temperature SCR reactor is connected to the input end of the induced draft fan, and the output end of the induced draft fan is connected to the input end of the chimney ; Pipelines connected to the ash bin are respectively arranged at the lower part of the waste heat boiler, the deacidification reaction tower, and the bag filter;

An SNCR spray gun is arranged on the top of the smoke outlet of the fire grate, and the input end of the SNCR spray gun is respectively connected to the output end of the SNCR ammonia buffer tank, the soft water tank and the first air compressor, and the input end of the SNCR ammonia buffer tank It is connected with the output end of the first ammonia water delivery pump; the ammonia water storage tank is provided with two output ends, which are respectively the first output end and the second output end, and the first output end of the ammonia water storage tank is connected with the first ammonia water delivery pump input connection;

The second output end of the ammonia water storage tank is connected to the input end of the second ammonia water delivery pump, the output end of the second ammonia water delivery pump is connected to the input end of the SCR ammonia water buffer tank, and the output end of the SCR ammonia water buffer tank It is connected with the input end of the ammonia evaporator, the output end of the ammonia evaporator is connected with the ammonia gas input end of the mixer, the output end of the second air compressor is connected with the air input end of the mixer, and the mixer The output end of is connected with the input end of the low-temperature SCR reactor.

The utility model adopts the "SNCR+low temperature SCR" combination out of stock, and the ammonia water storage tank is the common equipment of the SNCR system and the low temperature SCR system, and is the reducing agent storage unit of both. The first ammonia water delivery pump transports the reducing agent in the ammonia water storage tank to the SNCR ammonia water buffer tank, and then quantitatively mixes with the soft water in the soft water tank through the NOX emission feedback value, and distributes it to the spray gun in an appropriate temperature window. In the spray gun, it passes through the air The compressed air provided by the compressor atomizes the mixed solution of ammonia and water, and finally sprays it into the flue of the combustion furnace to achieve the purpose of preliminary removal of NOX. The second ammonia delivery pump in the low-temperature SCR unit delivers the reducing agent in the ammonia storage tank to the SCR ammonia buffer tank. The reducing agent passes through the ammonia evaporator and enters the mixer with the compressed air from the air compressor to fully dilute the reducing agent. Finally, it enters the low-temperature SCR reactor. At this time, the temperature of the flue gas is 140-160°C. The flue gas passes through the ammonia injection grid and the mixing unit in the low-temperature SCR reactor. Under the action of the low-temperature catalyst, the removal of NOX is realized.

The utility model has the advantages of (1) synchronously building SNCR+low temperature SCR, no modification is required after the NOX emission requirements are raised; (2) a large number of equipment can be shared, such as ammonia storage tanks, delivery modules, and control modules, saving investment costs; (3) SNCR is used when the emission requirements are low, and the SCR reactor is not equipped with a catalyst; (4) When the emission requirements are high, a catalyst is installed and the SCR is put into operation; The air can be heated again before entering the SCR reactor. The present invention can directly carry out the denitrification reaction at this temperature, saving the heat energy of the power plant; (6) The treated flue gas enters the desulfurization device and the bag filter respectively for Desulfurization and dust removal treatment, remove SO2 and dust in the flue gas, avoid damage to the subsequent low-temperature SCR catalyst, prolong the service life of the catalyst, and have certain economical efficiency; (7) NOX concentration of the flue gas after the process of the present invention It will be less than 100mg/Nm3, which meets the emission standard and has high efficiency.

Description of drawings

Fig. 1 is a system block diagram of the utility model.

Detailed ways

As shown in Figure 1, the utility model includes grate furnace 1, waste heat boiler 2, deacidification reaction tower 3, bag filter 4, ash bin 5, low temperature SCR reactor 6, induced draft fan 7, chimney 8, SNCR spray gun 9 , the first air compressor 10, the soft water tank 11, the SNCR ammonia water buffer tank 12, the first ammonia water delivery pump 13, the ammonia water storage tank 14, the second ammonia water delivery pump 15, the SCR ammonia water buffer tank 16, the ammonia evaporator 17, the mixer 18. The second air compressor 19.

The exhaust port of the grate furnace 1 is connected to the input end of the waste heat boiler 2, the output end of the waste heat boiler 2 is connected to the input end of the deacidification reaction tower 3, and the output end of the deacidification reaction tower 3 is connected to the cloth bag The input end of the dust collector 4 is connected, the output end of the bag filter 4 is connected with the input end of the low-temperature SCR reactor 6, the output end of the low-temperature SCR reactor 6 is connected with the input end of the induced draft fan 7, and the input end of the induced draft fan 7 is connected. The output end of the blower fan 7 is connected to the input end of the chimney 8; the pipes 20 connected with the ash bin 5 are respectively arranged at the lower part of the waste heat boiler 2, the deacidification reaction tower 3, and the bag filter 4.

An SNCR spray gun 9 is arranged on the top of the exhaust port of the grate furnace 1, and the input end of the SNCR spray gun 9 is respectively connected to the output end of the SNCR ammonia buffer tank 12, the soft water tank 11 and the first air compressor 10, and the SNCR spray gun 9 is connected to the output end of the first air compressor 10. The input end of the ammonia water buffer tank 12 is connected with the output end of the first ammonia water delivery pump 13; The ammonia water storage tank 14 is provided with two output ends, is respectively the first output end and the second output end, and the ammonia water storage tank 14 The first output end of is connected with the input end of the first ammonia water delivery pump 13.

The second output end of the ammonia water storage tank 14 is connected with the input end of the second ammonia water delivery pump 15, and the output end of the second ammonia water delivery pump 15 is connected with the input end of the SCR ammonia water buffer tank 16, and the SCR ammonia water buffer The output end of tank 16 is connected with the input end of ammonia evaporator 17, the output end of described ammonia evaporator 17 is connected with the ammonia gas input end of mixer 18, the output end of described second air compressor 19 is connected with mixer 18 The air input end of the mixer 18 is connected to the input end of the low-temperature SCR reactor 6 .

Claims (1)

1. the denitrating system that one way of life garbage power plant is energy-efficient, is characterized in that: comprise grate furnace, waste heat boiler, depickling reaction tower, sack cleaner, ash silo, low-temperature SCR reactor, air-introduced machine, chimney, SNCR spray gun, the first air compressor machine, softened water tank, SNCR ammonia water surge tank, the first ammonium hydroxide delivery pump, ammoniacal liquor holding vessel, the second ammonium hydroxide delivery pump, SCR ammoniacal liquor surge tank, ammonia evaporator, blender, the second air compressor machine;

The exhaust opening of described grate furnace is connected with the input of waste heat boiler, the output of described waste heat boiler is connected with the input of depickling reaction tower, the described output of depickling reaction tower is connected with the input of sack cleaner, the output of described sack cleaner is connected with the input of low-temperature SCR reactor, the described output of low-temperature SCR reactor is connected with the input of air-introduced machine, and the output of described air-introduced machine is connected with the input of chimney; In the bottom of described waste heat boiler, depickling reaction tower, sack cleaner, the pipeline be connected with ash silo is set respectively;

On the top of described grate furnace exhaust opening, SNCR spray gun is set, the input of described SNCR spray gun connects the output of SNCR ammonia water surge tank, softened water tank and the first air compressor machine respectively, and the input of described SNCR ammonia water surge tank is connected with the output of the first ammonium hydroxide delivery pump; Described ammoniacal liquor holding vessel is provided with two outputs, is respectively the first output and the second output, and the first output of described ammoniacal liquor holding vessel is connected with the input of the first ammonium hydroxide delivery pump;

Second output of described ammoniacal liquor holding vessel is connected with the input of the second ammonium hydroxide delivery pump, the output of described second ammonium hydroxide delivery pump is connected with the input of SCR ammoniacal liquor surge tank, the output of described SCR ammoniacal liquor surge tank is connected with the input of ammonia evaporator, the output of described ammonia evaporator is connected with the ammonia input of blender, the described output of the second air compressor machine is connected with the air input of blender, and the output of described blender is connected with the input of low-temperature SCR reactor.