CN217016043U - Flue gas treatment system - Google Patents
Flue gas treatment system Download PDFInfo
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- CN217016043U CN217016043U CN202220745924.4U CN202220745924U CN217016043U CN 217016043 U CN217016043 U CN 217016043U CN 202220745924 U CN202220745924 U CN 202220745924U CN 217016043 U CN217016043 U CN 217016043U
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Abstract
The utility model provides a flue gas treatment system which comprises an SNCR (selective non-catalytic reduction) system, an incinerator, a waste heat boiler, an SCR (selective catalytic reduction) reactor, a coal economizer, an air induction system and a chimney which are sequentially connected, wherein the SNCR system inputs excessive reducing agents for flue gas generated in the incinerator, the SCR reactor is used for carrying out denitration reaction on the flue gas, and the incinerator can decompose the reducing agents into ammonia gas. By adopting the scheme, the ammonia required by the catalytic reduction reaction is completely sprayed with excessive reducing agent based on the SNCR system, the reducing agent is decomposed into ammonia by utilizing the high temperature of the incinerator, and the flue gas and the ammonia are uniformly mixed under the action of the inner wall of the equipment, so that the reaction is full. The system does not need to be provided with a reducing agent evaporation or pyrolysis system, and also can not be provided with an ammonia spraying grid and a flue gas rectifying device, thereby optimizing the structure of the flue gas treatment system in the prior art, reducing the system fault points, improving the flue gas treatment effect and meeting the emission requirement.
Description
Technical Field
The utility model relates to the technical field of waste incineration treatment, in particular to a flue gas treatment system.
Background
With the increasing environmental protection requirements, the concentration limit of pollutants in incineration flue gas becomes stricter. The existing flue gas treatment technology comprises the combined application of selective non-catalytic reduction (SNCR), Selective Catalytic Reduction (SCR), high-temperature dust removal, dry method, semi-dry method, wet deacidification and the like, but in the actual operation process, due to the arrangement of the flow sequence, the regulation and control of the reaction temperature of each stage and the utilization rate of waste heat have some problems, such as complex process, large investment, waste heat waste and even larger secondary pollution (waste water, fly ash and the like).
In addition, in the conventional SCR process, an ammonia injection grid is arranged to inject ammonia gas into a reactor, the ammonia gas is generally prepared from a reducing agent, the reducing agent is urea or ammonia water, so a urea pyrolysis device or an ammonia gas evaporator (namely a reducing agent ammonia preparation system) is required to be arranged to convert a urea solution or an ammonia water solution into the ammonia gas, the ammonia gas is diluted and mixed by a dilution fan and a dilution air heater, then is injected into the SCR reactor through the ammonia injection grid, and is mixed and reacted with flue gas through a flue gas rectifier. The ammonia gas and the flue gas are mixed unevenly, so that the reaction is insufficient easily, and the denitration efficiency is reduced and the ammonia escape is increased. Meanwhile, ammonia gas preparation and heating dilution systems are complex, and system fault points are more.
SUMMERY OF THE UTILITY MODEL
The utility model provides a flue gas treatment system, which aims to optimize the structure of the flue gas treatment system in the prior art and improve the treatment effect.
In order to solve the above problems, according to one aspect of the present invention, the present invention provides a flue gas treatment system, which includes an SNCR system, an incinerator, a waste heat boiler, an SCR reactor, an economizer, an induced draft system, and a chimney, which are connected in sequence, wherein the SNCR system inputs an excessive amount of reducing agent into flue gas generated in the incinerator, the SCR reactor is used for performing a denitration reaction on the flue gas, and the incinerator can decompose the reducing agent into ammonia gas.
Furthermore, the flue gas treatment system also comprises a first flue gas monitoring device and a second flue gas monitoring device, wherein the first flue gas monitoring device is connected with the front end of the SCR reactor, and the second flue gas monitoring device is connected with the rear end of the SCR reactor so as to control the amount of ammonia entering the SCR reactor.
Further, the SCR reactor comprises a plurality of soot blowers and a plurality of reaction channels, the soot blowers and the reaction channels are all arranged in the SCR reactor, the reaction channels are arranged in an openable and closable manner, catalysts are arranged in the reaction channels, and the soot blowers and the reaction channels are arranged in a one-to-one correspondence manner.
Furthermore, the flue gas treatment system also comprises a dry-process reactor and a bag type dust collector, wherein the dry-process reactor is arranged between the SCR reactor and the economizer and is used for carrying out deacidification reaction on the flue gas, and the bag type dust collector is positioned at the output side of the economizer.
Furthermore, the flue gas treatment system also comprises a semidry method reactor, wherein the input end of the semidry method reactor is connected with the economizer, and the output end of the semidry method reactor is connected with the bag type dust collector; or the flue gas treatment system also comprises a cooling tower, the input end of the cooling tower is connected with the coal economizer, and the output end of the cooling tower is connected with the bag type dust collector.
Further, the flue gas flow in the semidry method reactor is more than or equal to 45000Nm3Under the condition of/h, a rotary atomizer is arranged in the semidry process reactor; the flow rate of the flue gas in the semidry method reactor is less than 45000Nm3In the case of/h, a two-fluid atomizer is provided in the semidry reactor.
Furthermore, the flue gas treatment system also comprises a spray gun, one end of the spray gun is connected with the SNCR system, the other end of the spray gun is connected with the incinerator, and the spray gun is used for spraying the reducing agent supplied by the SNCR system into a cavity of the incinerator.
Furthermore, the flue gas treatment system also comprises a first conveying part, and the first conveying part is connected with the front end of the dry reactor to spray slaked lime powder or sodium bicarbonate powder into the dry reactor.
Furthermore, the flue gas treatment system also comprises a second conveying part, and the second conveying part is connected with the front end of the bag type dust collector to spray activated carbon into the bag type dust collector.
Further, the output end of the bag type dust collector is connected with the SNCR system, so that the SNCR system is heated by the flue gas output by the bag type dust collector.
Further, the SNCR system adopts urea to be including preparing jar, demineralized water transfer chain, urea transfer chain and heat exchanger under the condition of reductant, and demineralized water transfer chain and bag collector all are connected with the heat exchanger to make the flue gas heat the demineralized water in the heat exchanger, the output of demineralized water transfer chain, the output of urea transfer chain all are connected with the preparation jar.
Further, the SNCR system still includes return line and booster pump, and the booster pump sets up on the return line, and the import of return line, the export of return line all communicate with the demineralized water transfer chain, and the heat exchanger is located between the import of return line and the export of return line, and the flow direction of the demineralized water in the return line is opposite with the flow direction of the demineralized water in the demineralized water transfer chain.
Furthermore, the structure of the heat exchanger contacting with the flue gas is made of enamel or stainless steel; the SNCR system also comprises a soft water tank, and the output end of the demineralized water conveying line is connected with the soft water tank.
The technical scheme of the utility model is applied to provide a flue gas treatment system, which comprises an SNCR system, an incinerator, a waste heat boiler, an SCR (selective catalytic reduction) reactor, an economizer, an induced draft system and a chimney which are sequentially connected, wherein the SNCR system inputs excessive reducing agent for flue gas generated in the incinerator, the SCR reactor is used for carrying out denitration reaction on the flue gas, and the incinerator can decompose the reducing agent into ammonia gas. By adopting the scheme, the ammonia required by the catalytic reduction reaction is completely sprayed with excessive reducing agent based on the SNCR system, the reducing agent is decomposed into ammonia by utilizing the high temperature of the incinerator, and the flue gas and the ammonia are uniformly mixed under the action of the inner wall of the equipment, so that the reaction is full. Therefore, the system does not need to be provided with a reducing agent evaporation or pyrolysis system (namely a reducing agent ammonia production system) or an ammonia spraying grid and a flue gas rectifying device, thereby optimizing the structure of the flue gas treatment system in the prior art, reducing the system fault points and improving the flue gas treatment effect.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the utility model and, together with the description, serve to explain the utility model and not to limit the utility model. In the drawings:
FIG. 1 is a schematic diagram of a flue gas treatment system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a flue gas treatment system according to a second embodiment of the present invention;
fig. 3 shows an enlarged view of the interior of the SNCR system of fig. 2.
Wherein the figures include the following reference numerals:
10. an SNCR system; 11. preparing a tank; 12. a demineralized water delivery line; 13. a urea delivery line; 14. a heat exchanger; 15. a return line; 16. a booster pump; 17. a soft water tank;
20. an incinerator;
30. a waste heat boiler;
40. an SCR reactor;
50. a dry reactor;
60. a coal economizer;
70. a bag type dust collector;
81. a semidry process reactor; 82. a spray gun; 83. a first conveying section; 84. a second conveying section; 85. a soot blower; 86. a first flue gas monitoring device; 87. a second flue gas monitoring device; 91. an induced draft system; 92. and (4) a chimney.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the utility model, and not restrictive of the full scope of the utility model. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the utility model, its application, or uses. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
As shown in fig. 1, a first embodiment of the present invention provides a flue gas treatment system, which includes an SNCR system 10, an incinerator 20, an exhaust-heat boiler 30, an SCR reactor 40, an economizer 60, an induced draft system 91, and a chimney 92, which are connected in sequence, wherein the SNCR system 10 inputs an excessive amount of reducing agent into flue gas generated in the incinerator 20, the SCR reactor 40 is used for performing a denitration reaction on the flue gas, and the incinerator 20 can decompose the reducing agent into ammonia gas. The induced draft system 91 can generate negative pressure to provide power for the flow of flue gas, and the chimney 92 is used for outputting the treated flue gas.
By adopting the scheme, the ammonia gas required by the catalytic reduction reaction is completely sprayed into excessive reducing agent based on the SNCR system 10, the reducing agent is decomposed into ammonia gas by utilizing the high temperature of the incinerator 20, and the flue gas and the ammonia gas are uniformly mixed under the action of the inner wall of the equipment, so that the reaction is complete. Therefore, the system does not need to be provided with a reducing agent evaporation or pyrolysis system (namely a reducing agent ammonia production system), and also can not be provided with an ammonia spraying grid and a flue gas rectifying device, so that the structure of the flue gas treatment system in the prior art is optimized, the system fault points are reduced, and the flue gas treatment effect is improved.
The flue gas treatment system in the prior art needs to be provided with a pre-dust collection device, a reducing agent evaporation or pyrolysis device, an ammonia spraying device, a flue gas rectification device and the like. The system is complex, the operation process is complex, factors influencing the removal efficiency are increased, the engineering investment cost is high, the energy consumption is high, and the operation cost is high.
The scheme adopts a SNCR + SCR treatment process, the SCR reaction temperature interval is 300-. The catalyst has low cost and high denitration efficiency, the system resistance of the dust collecting device is small, the reducing agent system is simple, and the reducing agent is contacted with the flue gas and is fully mixed uniformly. The system process is simplified on the basis of realizing higher denitration efficiency (80-90 percent), the energy is saved, and the investment and operation cost are reduced.
In this embodiment, the flue gas treatment system further includes a first flue gas monitoring device 86 and a second flue gas monitoring device 87, the first flue gas monitoring device 86 is connected to the front end of the SCR reactor 40, and the second flue gas monitoring device 87 is connected to the rear end of the SCR reactor 40 to control the amount of ammonia entering the SCR reactor 40. Through setting up first flue gas monitoring devices 86 and second flue gas monitoring devices 87, can control the ammonia volume that gets into SCR reactor 40 like this to the ammonia volume that keeps in SCR reactor 40 is in predetermined numerical range, thereby also can reduce or avoid the increase of ammonia escape when guaranteeing SCR reactor 40 denitration rate.
Specifically, the SCR reactor 40 includes a plurality of soot blowers 85 and a plurality of reaction channels, the plurality of soot blowers 85 and the plurality of reaction channels are all disposed in the SCR reactor 40, the plurality of reaction channels are openably and closably disposed, a catalyst is disposed in the plurality of reaction channels, and the plurality of soot blowers 85 and the plurality of reaction channels are disposed in one-to-one correspondence. By arranging the plurality of reaction channels, the mixed flue gas and ammonia gas can be ensured to be fully reacted, and the denitration rate of the SCR reactor 40 is improved; the reaction channels are arranged in a switchable manner, when the catalyst needs to be replaced, the corresponding reaction channel is closed, so that the replacement of the catalyst is realized, meanwhile, the operation of the whole production line is not influenced, and the production continuity is improved; the arrangement of the soot blowers 85 and the reaction channels in one-to-one correspondence can affect the service life and the reaction efficiency of the catalyst when the concentration of dust in the SCR reactor 40 is high, so that the soot blowers 85 can purge the ash on the catalyst to improve the reaction efficiency. The soot blower 85 can adopt a mode of combining steam soot blowing and shock wave soot cleaning, and simultaneously sets a higher soot blowing frequency, so that the soot blowing efficiency is improved conveniently.
Optionally, the SCR reactor 40 further comprises a plurality of flapper doors, the plurality of flapper doors and the plurality of reaction channels being arranged in one-to-one correspondence to open or close the plurality of reaction channels.
If the dust concentration is higher in the system and then the catalyst life and efficiency can be influenced, a part of processes are provided with a pre-dust collection device at present, the problem caused by dust is solved to a certain extent, the system resistance is increased, and the system energy consumption is increased and the cost is increased. In the scheme, a pre-dust collection device is not arranged, an effective catalyst soot blower 85 is arranged instead, various soot blowers 85 (steam soot blowing and shock wave soot cleaning) are combined, and a higher soot blowing frequency is set simultaneously to improve the soot blowing efficiency, so that the system is simple and effective.
The scheme has the following advantages or effects:
the SCR system is not provided with a reducing agent evaporation or pyrolysis system (namely a reducing agent ammonia production system), and is not provided with an ammonia injection grid and a flue gas rectifying device, ammonia required by catalytic reduction reaction is completely injected into excessive reducing agent solution based on an SNCR system, ammonia is generated by utilizing the high-temperature state of the incinerator, and flue gas and ammonia are uniformly mixed and fully reacted through the boiler and a water-cooled wall;
in the scheme, a pre-dust collection system is not arranged, and 2 or more soot blowers 85 are arranged above each layer of catalyst to ensure that the catalyst is not blocked by dust;
in the scheme, the SCR reactor is set to be in a multi-channel form, each reaction channel is separated by the baffle door, the baffle door is opened when the SCR reactor operates normally, the corresponding baffle door is closed when the catalyst needs to be replaced, the online replacement of the catalyst can be realized, and meanwhile, the load of a boiler is reduced to ensure that the smoke reaches the emission standard.
As shown in fig. 2 and fig. 3, in the second embodiment of the present invention, another flue gas treatment system is provided, in the first embodiment, on the basis of the SNCR system 10, the incinerator 20, the exhaust heat boiler 30, the SCR reactor 40, and the economizer 60, the flue gas treatment system further includes a dry reactor 50 and a bag-type dust collector 70, the dry reactor 50 is disposed between the SCR reactor 40 and the economizer 60, the dry reactor 50 is used for performing a deacidification reaction on flue gas, and the bag-type dust collector 70 is located at an output side of the economizer 60.
By adopting the scheme, the flue gas is treated by utilizing the combined treatment process of the SNCR system 10, the incinerator 20, the waste heat boiler 30, the SCR reactor 40, the dry-process reactor 50, the economizer 60 and the bag-type dust collector 70 which are connected in sequence, the temperature characteristic of the flue gas can be fully utilized by the combined treatment process, in addition, the SCR reactor 40 and the dry-process reactor 50 are arranged between the waste heat boiler 30 and the economizer 60, and the residual NH sprayed by the SNCR system 10 can be utilized by the arrangement3Denitration is carried out, so that a heat exchanger and equipment do not need to be additionally arranged, the process is simple, the treatment effect is good, and the emission requirement can be met.
The flue gas treatment system further comprises a semi-dry process reactor 81, the input end of the semi-dry process reactor 81 is connected with the economizer 60, and the output end of the semi-dry process reactor 81 is connected with the bag type dust collector 70; or the flue gas treatment system also comprises a cooling tower, the input end of the cooling tower is connected with the coal economizer 60, and the output end of the cooling tower is connected with the bag type dust collector 70. By arranging the semidry process reactor 81, the flue gas can be deacidified for the second time, enters the bag type dust collector 70 and then is subjected to subsequent treatment; the cooling tower is arranged, so that the temperature of the flue gas can be reduced to about 150 ℃ by spraying the flue gas cooling water, and the flue gas treatment cost is reduced.
Further, the flow rate of flue gas in the semidry method reactor 81 is not less than 45000Nm3In the case of/h, a rotary atomizer is provided in the semi-dry reactor 81; the flue gas flow in the semi-dry method reactor 81 is less than 45000Nm3In the case of/h, a two-fluid atomizer is provided in the semidry reactor 81. When in useThe flow rate of flue gas in the semidry method reactor 81 is more than or equal to 45000Nm3When the smoke is treated by the rotary atomizer, the smoke distance is large, and the rotary atomizer is suitable for treating the situation of large smoke quantity; when the flue gas flow rate in the semi-dry process reactor 81 is less than 45000Nm3And during the reaction, a double-fluid atomizer is adopted, so that the method is suitable for the smoke of a small incineration/pyrolysis furnace, and the wall sticking problem is effectively avoided.
Specifically, the flue gas treatment system further comprises a spray gun 82, one end of the spray gun 82 is connected with the SNCR system 10, the other end of the spray gun 82 is connected with the incinerator 20, and the spray gun 82 is used for spraying the reducing agent supplied by the SNCR system 10 into the cavity of the incinerator 20. The lance 82 is provided to inject the reductant supplied by the SNCR system 10 into the chamber of the incinerator 20 to provide a more complete reaction.
In this embodiment, the flue gas treatment system further comprises a first conveying part 83, and the first conveying part 83 is connected with the front end of the dry reactor 50 to inject the slaked lime powder or sodium bicarbonate powder into the dry reactor 50. By providing the first conveying unit 83, the slaked lime powder or the sodium bicarbonate powder can be conveyed to the dry reactor 50 to be sufficiently mixed with the flue gas and reacted, that is, the flue gas can be deacidified.
In this embodiment, the flue gas treatment system further comprises a second conveying part 84, and the second conveying part 84 is connected with the front end of the bag-type dust collector 70 to inject the activated carbon into the bag-type dust collector 70. Through setting up second conveying part 84, can carry the active carbon for bag collector 70, make its and flue gas intensive mixing adsorb heavy metal and dioxin in the flue gas, realize further flue gas cleanness.
Specifically, the output of the baghouse 70 is connected to the SNCR system 10 to heat the SNCR system 10 with the flue gas output by the baghouse 70. By adopting the arrangement mode, the SNCR system 10 can be heated by utilizing the flue gas output from the bag-type dust collector 70, and the utilization rate of energy is improved.
Wherein, SNCR system 10 adopts urea to be including preparing jar 11, demineralized water transfer chain 12, urea transfer chain 13 and heat exchanger 14 under the condition of reductant, and demineralized water transfer chain 12 and bag collector 70 all are connected with heat exchanger 14 to make the flue gas heat the demineralized water in heat exchanger 14, and the output of demineralized water transfer chain 12, the output of urea transfer chain 13 all are connected with preparation jar 11. Through the arrangement, the flue gas from the bag type dust collector 70 is conveyed into the heat exchanger 14 to heat the desalted water, and then the heated desalted water and the urea conveying line 13 enter the preparation tank 11 together, so that the preparation of the uric acid solution is carried out.
Further, the SNCR system 10 further includes a return line 15 and a booster pump 16, wherein the booster pump 16 is disposed on the return line 15, an inlet of the return line 15 and an outlet of the return line 15 are both communicated with the demineralized water delivery line 12, the heat exchanger 14 is disposed between the inlet of the return line 15 and the outlet of the return line 15, and a flow direction of the demineralized water in the return line 15 is opposite to a flow direction of the demineralized water in the demineralized water delivery line 12. By providing the return line 15 and the booster pump 16, the heat exchanger 14 can be reduced in size and cost.
In this embodiment, the structure of the heat exchanger 14 contacting with the flue gas is made of enamel or stainless steel; the SNCR system 10 further includes a soft water tank 17, and an output of the demineralized water delivery line 12 is connected to the soft water tank 17. The structure of the heat exchanger 14 in contact with the flue gas is made of enamel or stainless steel, so that the corrosion problem can be effectively relieved, and the service life of the heat exchanger 14 is prolonged. Wherein, a soft water tank 17 is provided to facilitate the storage of demineralized water.
According to the technical scheme provided by the utility model, can adopt following flue gas processing method, flue gas processing method includes: excessive reducing agent is sprayed into the incinerator 20, and the reaction temperature of the reducing agent and the flue gas in the incinerator 20 is 800-1000 ℃; ammonia gas is evaporated by utilizing the temperature of the incinerator 20, and escapes to be used as a reaction raw material of the SCR reactor 40; the ammonia gas, the flue gas and the catalyst are subjected to selective catalytic reduction reaction in the SCR reactor 40 at the temperature range of 300-350 ℃ to remove the nitrogen oxides from the flue gas.
By adopting the flue gas treatment method, the reaction temperature of the reducing agent and the flue gas in the incinerator 20 is controlled within 1000 ℃, the removal efficiency can reach about 50 percent, and then the SCR system utilizes the excessive ammonia generated by the front-stage SNCR system as a raw material and does not need to independently arrange a device for spraying the reducing agent into the SCR system and the dust removal device; the reaction temperature is controlled within 300-350 ℃, and selective catalytic reduction reaction is carried out on ammonia gas, flue gas and the catalyst, so that the denitration efficiency can be more than 80%.
Wherein, the flue gas treatment method also comprises the following steps: the amount of ammonia entering the SCR reactor 40 is monitored and the amount of ammonia exiting the SCR reactor 40 is monitored to control the amount of ammonia in the SCR reactor 40. By adopting the monitoring mode, the amount of ammonia entering the SCR reactor 40 can be controlled to keep the amount of ammonia in the SCR reactor 40 within a preset numerical range, thereby ensuring the denitration rate of the SCR reactor 40.
Wherein, the flue gas treatment method also comprises the following steps: the denitrated flue gas output by the SCR reactor 40 enters a dry reactor 50, the agent in the dry reactor 50 is slaked lime or sodium bicarbonate, the reaction temperature in the dry reactor 50 is 280-350 ℃, and the retention time of the flue gas in the dry reactor 50 is 0.2-0.5 s; the flue gas output by the dry-process reactor 50 enters a semi-dry-process reactor 81 through an economizer 60, the retention time of the flue gas in the semi-dry-process reactor 81 is not less than 15s, and the alkaline solution in the semi-dry-process reactor 81 is NaOH solution or lime milk solution; wherein, when the deacidification effect in the dry reactor 50 reaches the preset standard, the alkaline solution is stopped to be sprayed in the semi-dry reactor 81, and the temperature of the flue gas is reduced to 140-160 ℃, preferably 150 ℃ by spraying cooling water.
The denitrated flue gas output by the SCR reactor 40 enters a dry reactor 50, meanwhile, slaked lime or sodium bicarbonate is added into the dry reactor 50, the reaction temperature is controlled within 280-350 ℃, after the denitration flue gas stays for 0.2-0.5s, the flue gas can be fully mixed with the slaked lime or the sodium bicarbonate, the deacidification rate can be between 50-90%, wherein the injection amount of the slaked lime and the sodium bicarbonate can be determined according to the emission concentration of acidic pollutants in the flue gas which is set as required; the calcium-sulfur ratio is 1.5-3. After entering the semi-dry reactor 81, alkaline solution of NaOH solution or lime milk solution is used for secondary deacidification, if the requirement of environmental emission is met, alkaline solution injection is stopped in the semi-dry reactor 81, only smoke cooling water is injected to reduce the smoke temperature to 160 ℃, preferably 150 ℃, and the smoke treatment cost is reduced.
Further, semidry reactionThe flue gas flow in the device 81 is more than or equal to 45000Nm3When the flow rate of the flue gas in the semi-dry reactor 81 is less than 45000Nm by adopting a mechanical rotary semi-dry method3When the reaction time is/h, a two-fluid spraying semi-dry method is adopted; wherein, the raw material of the two-fluid spraying semi-dry method is NaOH solution with the concentration of 5-10% or lime milk solution with the concentration of 5-8%. By adopting the method, a rotary atomizer or a double-fluid atomizer can be selected for atomization according to the size of the smoke gas, the particle size of atomized particles is 40-80 micrometers, the smoke gas stays in a semidry method reactor 81 for about 15s, the injection amount of lime milk solution or NaOH solution required by a mechanical rotary semidry method is controlled according to an online emission monitoring value, and the water amount for cooling the smoke gas is controlled according to the smoke temperature at the inlet of a bag type dust collector. The double-fluid spraying semi-dry method adopts lime milk solution with low concentration (4-8%) or NaOH (5%) solution, the spraying amount is controlled according to the temperature of flue gas entering a subsequent bag type dust collector, and the deacidification efficiency is about 90%.
Further, the flue gas treatment method further comprises the following steps: the flue gas output by the semidry method reactor 81 enters a bag type dust collector 70, activated carbon is sprayed into the bag type dust collector 70, and the activated carbon and the flue gas are mixed to adsorb heavy metals and dioxin in the flue gas; the unreacted slaked lime or sodium bicarbonate powder, the activated carbon powder and the smoke dust in the smoke are intercepted on the surface of the filter material in the bag-type dust collector 70 and continuously react with the smoke.
Flue gas output by the semidry method reactor 81 enters the bag type dust collector 70, activated carbon injection is arranged in front of the bag type dust collector 70, the activated carbon and the flue gas can be fully mixed and can adsorb heavy metals and dioxin in the flue gas, unreacted and complete slaked lime or sodium bicarbonate powder, activated carbon powder and smoke dust in the flue gas can be intercepted on the surface of a filter material in the bag type dust collector 70 and continuously react with acidic pollutants, the heavy metals and the dioxin in the flue gas, further flue gas cleaning is realized, and the flue gas is discharged after reaching the standard.
Wherein each 1Nm in the bag-type dust collector 703The smoke amount is sprayed into 100-120mg of activated carbon, the material of the filter material is PTFE + PTFE membrane, the length of the filter material is not more than 8m, and the pinhole of the filter material is sealed by PTFE glue. According to the above method, the amount of the activated carbon to be sprayed can be determined according toRegulating and determining smoke amount, wherein the smoke amount is every 1Nm3The smoke amount is sprayed into 100-120mg of active carbon; the material with the filter material sets up to PTFE + PTFE tectorial membrane, and the length of filter material is no longer than 8m, and the pinhole department of filter material is sealed with PTFE glue, can improve the deashing effect like this. Wherein, the needle eye of the filter material is sealed by PTFE glue, and the glue can be polytetrafluoroethylene.
To facilitate understanding of the present solution, further description is provided below.
The first concrete example of the technical scheme provided by the utility model is as follows:
the flue gas parameters without denitration and deacidification treatment are as follows:
ammonia water is adopted as a reducing agent, the ammonia water is treated by the process of the system, 25% of ammonia water solution is diluted to about 5% and is excessively sprayed into the incinerator through an SNCR spraying system, the using amount of the 25% of ammonia water solution is 70kg/h, the temperature range of a spraying interval is 800-900 ℃, and then flue gas enters an SCR reactor through a waste heat boiler, wherein the reaction temperature is 320 ℃; the dry deacidification raw material is slaked lime (purity is 90 percent), the spraying amount is 315kg/h, the semidry deacidification tower is provided with a rotary atomizer, only water is sprayed to cool the flue gas, the spraying amount of the activated carbon is 10kg/h, and the concentrations of pollutants in the treated flue gas are respectively as follows: NOx is less than or equal to 50mg/Nm3、SO2≤40mg/Nm3，HCl≤10mg/Nm3The particle content is less than or equal to 5mg/Nm3。
The second specific example of the technical solution provided by the present invention is:
the flue gas parameters without denitration and deacidification treatment are as follows:
urea is adopted as a reducing agent, and through the system process treatment of the utility model, the SNCR prepares 40 percent urea solution, the urea solution is diluted to about 5 percent and is excessively sprayed into the incinerator through an SNCR spraying system, and the purity of the urea solution is 98.6 percentThe using amount of elements is 22.5kg/h, the temperature range of an injection interval is 950-: NOx is less than or equal to 50mg/Nm3、SO2≤30mg/Nm3，HCl≤10mg/Nm3The particle content is less than or equal to 5mg/Nm3。
The utility model fully utilizes the technical characteristics of flue gas denitration and deacidification, selects an optimal reaction temperature range, is not provided with a flue gas heat exchange device and a pre-dedusting device, and has the advantages of small system resistance, low energy consumption and high denitration and deacidification efficiency. The temperature of 300-350 ℃ is the relatively excellent activity interval of the catalyst, the utility model utilizes the selection of the medium-temperature catalyst, avoids the problem that the low-temperature catalyst wastes energy by adopting an external heat source for heating, and reduces the system resistance by adopting a soot blower instead of a pre-dust removal system. The optimal reaction temperature interval of the dry deacidification is 280-350 ℃, which is just positioned at the downstream of the medium-temperature SCR (300-350 ℃), so that the dry deacidification efficiency is exerted to the maximum extent, the system is simple, and the investment is low. Semi-dry deacidification is a supplement of dry deacidification, bears a smaller deacidification load, can adopt a low-concentration alkaline raw material, and effectively relieves the problems of abrasion, blockage and the like of an atomizer; the rotary atomizer has larger fog distance and is suitable for treating projects with larger smoke quantity, and the double-fluid spraying semi-dry method is suitable for smoke of small incineration/pyrolysis furnaces, thereby effectively avoiding the problem that the rotary atomizer is adhered to walls. The utility model has the advantages of simple process system, low one-time investment, small system resistance, low power consumption in operation and good denitration and deacidification effects.
The utility model utilizes the waste heat of the flue gas to heat the demineralized water, the heated demineralized water is conveyed to the preparation tank for dissolving the urea, the preparation tank has the heat preservation function, and the dissolved urea solution with the concentration of 40 percent is conveyed to the SNCR system and the dilution water tank. Because the flue gas contains Cl-And the smoke side material of the heat exchanger is made of enamel or stainless steel materials, so that the corrosion problem can be effectively relieved, and the service life of the heat exchanger is prolonged. Wherein the temperature of the flue gas outlet after heat exchange of the heat exchanger is 125 DEG CThe above; the water side of the heat exchanger is desalted water which is used as a solvent for preparing the urea solution, the outlet water temperature of the desalted water side is 70-90 ℃, the solution is prepared uniformly, the heat efficiency is high, the problem of crystallization and precipitation of the urea solution is effectively solved, and the denitration efficiency is improved. A flow meter and an adjusting valve are arranged on a pipeline from the water side of the heat exchanger to the desalted water at the inlet of the urea preparation tank, the amount of water is adjusted according to the preparation requirement of the urea solution, the residual water flows back to the inlet of the heat exchanger through a reflux pump, the water temperature at the inlet of the heat exchanger is ensured to be 60-70 ℃, and the corrosion problem of the heat exchanger is effectively relieved.
The third concrete example of the technical scheme provided by the utility model is as follows:
according to the parameters, the heat exchanger is made of enamel, and the area of the heat exchanger is 65m2The temperature of a smoke outlet is higher than the dew point temperature, the temperature of the outlet water on the side of the heat exchanger is 80 ℃ and is used for preparing 40% urea solution, a urea solution preparation tank is arranged for heat preservation, a heating system is not needed, the solution is uniformly mixed, and the problem of urea crystallization precipitation is solved.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (13)
1. The flue gas treatment system is characterized by comprising an SNCR system (10), an incinerator (20), a waste heat boiler (30), an SCR reactor (40), an economizer (60), an air inducing system (91) and a chimney (92) which are sequentially connected, wherein the SNCR system (10) inputs excessive reducing agents for flue gas generated in the incinerator (20), the SCR reactor (40) is used for carrying out denitration reaction on the flue gas, and the incinerator (20) can decompose the reducing agents into ammonia gas.
2. The flue gas treatment system according to claim 1, further comprising a first flue gas monitoring device (86) and a second flue gas monitoring device (87), the first flue gas monitoring device (86) being connected to a front end of the SCR reactor (40), the second flue gas monitoring device (87) being connected to a rear end of the SCR reactor (40) for controlling an amount of ammonia entering the SCR reactor (40).
3. The flue gas treatment system of claim 1, wherein the SCR reactor (40) comprises a plurality of soot blowers (85) and a plurality of reaction channels, wherein the plurality of soot blowers (85) and the plurality of reaction channels are each disposed within the SCR reactor (40), wherein the plurality of reaction channels are switchably disposed, wherein the plurality of reaction channels are each disposed with a catalyst, and wherein the plurality of soot blowers (85) and the plurality of reaction channels are disposed in one-to-one correspondence.
4. The flue gas treatment system according to claim 1, further comprising a dry reactor (50) and a bag house (70), the dry reactor (50) being arranged between the SCR reactor (40) and the economizer (60), the dry reactor (50) being used for deacidifying flue gas, the bag house (70) being located at the output side of the economizer (60).
5. The flue gas treatment system of claim 4,
the flue gas treatment system further comprises a semi-dry process reactor (81), the input end of the semi-dry process reactor (81) is connected with the economizer (60), and the output end of the semi-dry process reactor (81) is connected with the bag type dust collector (70); or the like, or, alternatively,
the flue gas treatment system further comprises a cooling tower, wherein the input end of the cooling tower is connected with the coal economizer (60), and the output end of the cooling tower is connected with the bag type dust collector (70).
6. The flue gas treatment system of claim 5, which isIs characterized in that the flow rate of flue gas in the semi-dry reactor (81) is more than or equal to 45000Nm3In the case of/h, a rotary atomizer is arranged in the semidry process reactor (81); the flow rate of flue gas in the semi-dry method reactor (81) is less than 45000Nm3In case of/h, a two-fluid atomizer is provided in the semi-dry reactor (81).
7. The flue gas treatment system according to claim 4, further comprising a lance (82), one end of the lance (82) being connected to the SNCR system (10) and the other end of the lance (82) being connected to the incinerator (20), the lance (82) being adapted to inject reductant supplied by the SNCR system (10) into the cavity of the incinerator (20).
8. The flue gas treatment system according to claim 4, further comprising a first conveyor (83), the first conveyor (83) being connected to the front end of the dry reactor (50) for injecting slaked lime powder or sodium bicarbonate powder into the dry reactor (50).
9. The flue gas treatment system of claim 4 further comprising a second conveyor (84), the second conveyor (84) being connected to the front end of the baghouse (70) for injecting activated carbon into the baghouse (70).
10. The flue gas treatment system of claim 4 wherein the output of the baghouse (70) is connected to the SNCR system (10) to facilitate heating of the SNCR system (10) by flue gas output from the baghouse (70).
11. The flue gas treatment system of claim 10, wherein the SNCR system (10) comprises a preparation tank (11), a demineralized water delivery line (12), a urea delivery line (13) and a heat exchanger (14) when urea is used as the reducing agent, wherein the demineralized water delivery line (12) and the bag-type dust collector (70) are connected with the heat exchanger (14) so as to heat the demineralized water in the heat exchanger (14), and wherein an output end of the demineralized water delivery line (12) and an output end of the urea delivery line (13) are connected with the preparation tank (11).
12. The flue gas treatment system of claim 11, wherein the SNCR system (10) further comprises a return line (15) and a booster pump (16), the booster pump (16) being disposed on the return line (15), an inlet of the return line (15) and an outlet of the return line (15) each being in communication with the demineralized water delivery line (12), the heat exchanger (14) being located between the inlet of the return line (15) and the outlet of the return line (15), the flow direction of the demineralized water in the return line (15) being opposite to the flow direction of the demineralized water in the demineralized water delivery line (12).
13. The flue gas treatment system according to claim 11, wherein the structure of the heat exchanger (14) in contact with the flue gas is made of enamel or stainless steel; the SNCR system (10) further comprises a soft water tank (17), and the output end of the demineralized water conveying line (12) is connected with the soft water tank (17).
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114602313A (en) * | 2022-04-01 | 2022-06-10 | 中国恩菲工程技术有限公司 | Flue gas treatment system and flue gas treatment method |
| CN117298847A (en) * | 2023-11-21 | 2023-12-29 | 北京达华洁能工程技术有限公司 | Low-nitrogen combustion denitration device and control method |
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2022
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114602313A (en) * | 2022-04-01 | 2022-06-10 | 中国恩菲工程技术有限公司 | Flue gas treatment system and flue gas treatment method |
| CN114602313B (en) * | 2022-04-01 | 2024-05-28 | 中国恩菲工程技术有限公司 | Flue gas treatment system and flue gas treatment method |
| CN117298847A (en) * | 2023-11-21 | 2023-12-29 | 北京达华洁能工程技术有限公司 | Low-nitrogen combustion denitration device and control method |
| CN117298847B (en) * | 2023-11-21 | 2024-03-19 | 北京达华洁能工程技术有限公司 | Low-nitrogen combustion denitration device and control method |
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