CN210215262U - Ultra-low emission denitration device for ERDIII cement plant - Google Patents
Ultra-low emission denitration device for ERDIII cement plant Download PDFInfo
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- CN210215262U CN210215262U CN201920847401.9U CN201920847401U CN210215262U CN 210215262 U CN210215262 U CN 210215262U CN 201920847401 U CN201920847401 U CN 201920847401U CN 210215262 U CN210215262 U CN 210215262U
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Abstract
The utility model discloses an ultralow denitrification facility that discharges of ERDIII cement plant, the ultralow denitrification facility that discharges of ERDIII cement plant includes a dore furnace, a powder denitration agent conveyor, the bottom of dore furnace is provided with the overgrate air entry, overgrate air entry linkage cement rotary kiln, the dore furnace is by supreme reduction zone, main combustion area, reburning district and the district of burning out of including down, reduction zone saturated steam catalytic burner is installed to the reduction zone, reburning district installs reburning district saturated steam catalytic burner, main combustion area connects the tertiary air, the district of burning out connects the overfire air, denitration agent spray gun is connected to powder denitration agent conveyor's discharging pipe, the denitration agent spray gun is connected the reburning district. The utility model discloses an introduce the denitration catalyst, reduced the use amount of denitration aqueous ammonia, practiced thrift the cost, reduced ammonia escape, more economic environmental protection, the reduction of ammonia escape has avoided the corruption to follow-up equipment.
Description
Technical Field
The invention belongs to the field of flue gas denitration of cement production lines, and particularly relates to an ultralow-emission denitration device for an ERDIII cement plant.
Background
Files such as a twelve-five energy-saving emission-reduction comprehensive working scheme (national issue [ 2011 ] 26), a national environmental protection twelve-five planning (national issue [ 2011 ] 42), an energy-saving emission-reduction twelve-five planning (national issue [ 2012 ] 40), "a key area atmospheric pollution control twelve-five" planning (ring issue [ 2012 ] 130), "a bulletin about executing a special emission limit value of atmospheric pollutants (environmental protection department bulletin 2013, No. 14) and the like clearly stipulate that the NOx emission amount in the cement industry in 2015 is controlled at 150 ten thousand tons, and the lagging capacity of the eliminated cement is 3.7 hundred million tons; for the nitrogen reduction and denitration of the novel dry-process kiln, the comprehensive denitration efficiency of the new, improved and expanded cement production line is not lower than 60 percent; in the key areas of air pollution prevention, the cement industry is subject to stricter special emission limits. The emission limit of NOx in the emission Standard of atmospheric pollutants for the Cement industry (GB4915-2013) is 800mg/Nm3Increased to 400 mg/Nm3300 mg/Nm from 1/20173. At present, the NOx emission limit value of a cement kiln and a kiln tail waste heat utilization system in an important area is 300 mg/Nm3The nitrogen oxide emission standard of partial regions reaches 200 mg/Nm3And 150 mg/Nm3And even lower. Entering thirteen five, the change of the environment-friendly situation puts higher requirements on the prevention and treatment of the atmospheric pollution of the cement plant, particularly on the total emission amount of NOx.
SNCR selective non-catalytic reduction denitration, namely a denitration technology with the largest market share, wherein the ammonia nitrogen ratio is designed to be 1-1.5. Denitration running cost is high, has increased enterprise's burden.
The utility model with application number 201720210300.1, which is applied by the applicant on 3/6/2017, discloses an ERD + coal-fired saturated steam catalytic combustion denitration device, which comprises a decomposing furnace, wherein the bottom of the decomposing furnace is provided with a secondary air inlet which is connected with a cement rotary kiln; the lower section of the decomposing furnace comprises a reduction zone, a main combustion zone and a reburning zone from bottom to top, and a reduction zone saturated steam catalytic burner and a reburning zone saturated steam catalytic burner are respectively arranged in the reduction zone and the reburning zone; the reduction zone saturated steam catalytic burner and the reburning zone saturated steam catalytic burner are connected with a steam flow metering device, the steam flow metering device is connected with a steam pressure stabilizing tank, and the steam pressure stabilizing tank is connected with a main steam pipeline. The disadvantages of this patent are:
(1) the ERD + coal-fired saturated steam catalytic combustion denitration technology still cannot meet the requirement that the NOx emission concentration is stably maintained within 50mg/Nm or stably operates in 50mg/Nm, and a large amount of ammonia water is sprayed to cause secondary pollution.
(2) The ERD + comprehensive denitration efficiency reaches more than 80 percent, and the lower emission requirement cannot be met.
(3) The consumption of ammonia water is still high, and a large amount of ammonia spraying water is pursued to discharge in an ultralow way, but the ammonia escape is high easily, and the follow-up equipment is also corroded.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides an ultralow emission denitration device for an ERDIII (efficient reburning denitration) cement plant, which can meet the requirement of ultralow emission of NOx (the emission concentration of NOx is stably maintained within 50mg/Nm year), has high system stability, optimizes a clinker production process, promotes the full combustion of pulverized coal, avoids the afterburning phenomenon, has high denitration efficiency and low ammonia escape rate, effectively reduces the investment cost of government and enterprises for controlling environmental pollution, improves the local atmospheric environment quality, and further reduces the NOx pollution discharge cost of the cement plant.
In order to achieve the purpose, the invention adopts the following technical scheme:
an ultra-low emission denitration device for an ERDIII cement plant comprises a decomposing furnace and a powder denitration agent conveying device, wherein a secondary air inlet is formed in the bottom of the decomposing furnace, the secondary air inlet is connected with a cement rotary kiln, the decomposing furnace comprises a reduction area, a main combustion area, a reburning area and a burnout area from bottom to top, the reduction area is provided with a reduction area saturated steam catalytic burner, the reburning area is provided with a reburning area saturated steam catalytic burner, the reduction area is connected with a reduction coal powder pipeline, the main combustion area is connected with a main coal powder pipeline, the reburning area is connected with a reburning coal powder pipeline, the main combustion area is connected with tertiary air, the burnout area is connected with burnout air, a discharge pipe of the powder denitration agent conveying device is connected with a denitration agent spray gun, the denitration agent spray gun is connected with the reburning area, and the joint of the decomposing furnace and the cement rotary kiln is provided with C5, the C5 is a fifth-stage preheating separator, an SNCR spray gun is arranged at the outlet of the C5, and the burnout zone is communicated with the C5.
As a preferred technical scheme, the powder denitration conveying device comprises a storage bin, an activation hopper, a pneumatic gate valve, a metering feeder, a weighing screw conveyor, a gas-solid separator, a feeder, a Roots blower and a discharge pipe, the top end of the bin is provided with a feed inlet, the lower end of the bin is communicated with the top end of the activation hopper, the bottom end of the activation hopper is communicated with the inlet end of the metering feeder, a pneumatic gate valve is arranged between the activation hopper and the metering feeder, the outlet end of the metering feeder is communicated with the inlet end of the weighing screw conveyor, the outlet end of the weighing screw conveyer is communicated with the gas-solid separator which is communicated with the feeder, the feeder is communicated with the discharge pipe, one end of the discharge pipe is connected with the Roots blower, the other end of the discharge pipe is connected with the decomposing furnace, and a pneumatic arch breaking device and a vibrator are arranged on the side wall in the storage bin.
As a preferable technical scheme, the denitration agent spray gun is provided with a plurality of and evenly distributed in the reburning area.
As a preferable technical scheme, a pressure transmitter is arranged on the discharge pipe and is arranged between the Roots blower and the feeder.
As a preferable technical scheme, the main combustion area is provided with a C4 feeding pipe which enters a first raw material inlet of the decomposing furnace, the reduction area is provided with a C4 feeding pipe which enters a second raw material inlet of the decomposing furnace, the C4 is a fourth-stage preheating separator, and the C4 feeding pipe is provided with an electric three-way valve.
As a preferable technical scheme, the main burning zone is provided with a tertiary air inlet, the burnout zone is provided with an overfire air inlet, and the tertiary air inlet and the overfire air inlet are communicated with a cooler of the rotary cement kiln.
According to the preferable technical scheme, the reduction zone saturated steam catalytic combustor and the reburning zone saturated steam catalytic combustor are connected with a steam flow metering device, the steam flow metering device is connected with a steam pressure stabilizing tank, and the steam pressure stabilizing tank is connected with a main steam pipeline.
Preferably, the number of the C5 is 2, and the C5 is stacked on both sides of the decomposing furnace.
The invention relates to an ultra-low emission denitration technology of an ERDIII cement plant, which is developed by an ERD + coal-fired saturated steam combustion technology by the applicant, and has high efficiency and low operation cost.
The ERDIII is suitable for implementation on the basis of technical improvement of denitration of a decomposing furnace, is particularly suitable for supplementary implementation on the basis of an ERD + coal-fired saturated steam catalytic combustion denitration technology, and has an ammonia-free comprehensive denitration rate of over 95 percent after implementation, so that ultralow emission of nitrogen oxides in a cement plant can be realized, the using amount of ammonia water can be greatly reduced, and powerful technical support is provided for energy conservation and emission reduction of the cement plant.
1. Ultra-low emission denitration technical principle of ERDIII cement plant
The ultra-low emission denitration technology of the ERDIII cement plant divides the decomposing furnace into a reduction zone, a main combustion zone, a reburning zone and a burnout zone from bottom to top by controlling the flow and the trend of fuel and hot air in the decomposing furnace. Distributing the fuel and the tertiary air in the same proportion in the main combustion area, so that the fuel is fully combusted in the main combustion area to release heat, and the smoke chamber crusting of the cone part of the decomposing furnace is reduced; adding a part of fuel at the upper part of the main combustion area, forming a reburning area under the anoxic atmosphere, reducing the formed nitrogen oxides by using active groups such as hydrocarbon groups, CO, HCN, CN, NHi and the like generated by reduction combustion, inhibiting the conversion of the nitrogen oxides, and effectively reducing the nitrogen oxides generated in the kiln and the main combustion area of the decomposing furnace; and partial tertiary air is added to the upper part of the reduction to ensure the burning-out of the fuel.
1) Basic principle of NOx reduction by reburning denitration technology
NOx is reduced to N when encountering hydrocarbon radicals CHi, incomplete combustion products CO, C, and incomplete combustion intermediates HCN groups, NHi groups2The fuel accounting for 80-85% of the total heat of the furnace is fed into α & gt 1 main combustion area to convert the nitrogen in the fuel into NOx as much as possible, the rest fuel accounting for 15-20% of the total heat of the furnace is fed into the reburning area at the upper part of the main combustion area to form reducing atmosphere under α & lt 1, so that the NOx generated in the main combustion area is reduced into nitrogen molecules in the reburning area, and the new NOx is inhibited from generating to further reduce the NOx emission concentration.
2) Chemical reaction mechanism for reducing NOx by reburning denitration technology
The hydrocarbon radicals CHi, CO, coke and the incomplete combustion intermediate HCN group generated by reburning the pulverized coal in a reducing atmosphere control the reburning to reduce the level of NOx emission through the following two main reactions:
C，CH，CH2＋NO→HCN＋…(1)
HCN＋O，OH→N2＋…(2)
the two responses with the greatest sensitivity coefficient are:
H＋O2→OH＋O(3)
C，CH，CH2＋NO→HCN＋…(4)
HCN is a very important intermediate product in the mechanism of reburning to reduce NOx emissions, and in the case of fuel-rich conditions, the following reactions occur:
CHi＋NO→HCN＋…(5)
HCN is then reduced to N by the following reaction2：
HCN＋O→NCO＋H(6)
NCO＋H→NH＋CO(7)
NH＋H→N＋H2(8)
N＋NO→N2＋O(9)
The intermediate product amino of the partially reburning coal powder under the reducing atmosphere is also an important way for reducing NOx generated in the main combustion zone:
NO＋NHi→N2＋…(10)
therefore, during the reduction reaction of the pulverized coal in the reburning zone on the nitrogen oxides generated by burning the pulverized coal in the main burning zone in the reducing atmosphere, the intermediate products such as cyano, amino, hydrocarbon radicals and the like generated in the reburning fuel play a role in decomposing the nitrogen oxides. In practical application, the reburning zone is required to generate a reducing atmosphere, hydrocarbon radicals CHi are contacted with NO as much as possible, and the CHi is prevented from being contacted with O, so that the effect of fuel staged combustion on reducing NOx emission is ensured.
2. Chemical reaction principle of ultra-low emission denitration technology in ERDIII cement plant
The denitration catalyst is catalytically cracked into small molecular groups at the high temperature of 900-1100 ℃ in the main combustion zone, has reducibility as a catalyst and promotes the following reaction. The reaction is as follows:
CxHy+O2——>CO + H2+CaHb• + C…… ①
NOx + CaHb•——>N2+ H2O ②
C+H2+NOx+CO——>N2+ H2O+CO2③
the denitration reaction is carried out by taking the denitration catalyst as a reducing agent at the high temperature of 900-1100 ℃: various reductive small-molecule free radical groups H generated by organic component decomposition2H, c, and cahb. Wherein the denitration performance of the intermediate CxHy is optimal. Transition metal complex oxidation of ironThe compound can promote the decomposition of organic molecules into micromolecules CaHb, promote the reaction of the micromolecules CaHb and NOx and prevent the CaHb from excessively reacting with O2.
Compared with the prior art, the invention has the beneficial effects that:
(1) the ERDIII cement plant ultra-low emission denitration technology is suitable for implementation on the basis of technical improvement of denitration of a decomposing furnace, is implemented by supplementing on the basis that the ERD + coal-fired saturated steam catalytic combustion denitration technology is independently developed by our company, and the ammonia-free comprehensive denitration rate reaches more than 95% after implementation, so that the ultra-low emission of nitrogen oxides in the cement plant can be realized, the using amount of ammonia water can be greatly reduced, and powerful technical support is provided for energy conservation and emission reduction of the cement plant.
(2) By introducing the denitration catalyst, the quality of the denitration catalyst product is comprehensively improved by 1-2%; because the preheating system is stable, the decomposition rate of the decomposing furnace is improved, the load of the kiln is reduced, and the product quality is stably improved. The denitration catalyst reduces the use amount of denitration ammonia water, saves cost, reduces ammonia escape, is more economical and environment-friendly, and avoids corrosion to subsequent equipment due to the reduction of ammonia escape.
(3) The operation cost is low, the denitration catalyst is supplemented after 50% of nitrogen oxides are removed (namely after the ERD and coal-fired saturated steam catalytic combustion denitration technology is implemented), and the operation cost is greatly reduced.
(4) The ultra-low emission denitration technology of the ERDIII cement plant can further realize higher denitration efficiency, and finally realize ammonia-free denitration. The process for controlling the nitrogen oxide by the ultra-low emission denitration technology of the ERDIII cement plant has higher denitration efficiency, the consumption of the reducing agent required by control after combustion is greatly reduced, the ammonia nitrogen ratio is designed to be 0-0.8, the possibility of ammonia escape is reduced from the source, and the ammonia escape can be controlled to be 6ppm (4.55 mg/m)3) Within.
(5) The ultra-low emission denitration technology of the ERDIII cement plant optimizes the process of a combustion system and simultaneously controls the generation of nitrogen oxides, and has the advantages of simple process flow, low operation cost, high system stability, optimized clinker production process and high denitration efficiency. It reduces the investment cost of government and enterprise in treating environmental pollution, and changesImproves the quality of local atmospheric environment and further reduces the NOx pollution discharge cost of cement plants. Provides a new mode of environmental protection, energy conservation and emission reduction for denitration in the cement industry. After the ultra-low emission denitration technology of the ERDIII cement plant is implemented, the NOx emission index is advanced, the environmental pollution can be effectively reduced, the harm to the human health is reduced, the purposes of energy conservation and emission reduction are achieved, the NOx emission meets the continuously improved environmental protection standard of China, and finally the NOx emission standard is controlled to be 50mg/Nm at the lowest operation cost3And realizing the stable operation of nitrogen oxide in 10-20 mg/Nm. The requirement of ultralow emission of a cement plant is met, and the dilemma that many cement plants cannot produce due to the ultralow emission is practically solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic structural diagram of an ultra-low emission denitration device of an ERDIII cement plant.
Fig. 2 is a schematic structural view of the powder denitration agent conveying device in fig. 1.
FIG. 3 is a schematic diagram showing the relationship between the ammonia-nitrogen ratio and the denitration efficiency of the SNCR system of the present invention.
Wherein the reference numerals are specified as follows: pulverized coal 1, a reduction zone 2, a reduction pulverized coal pipeline 2A, a main combustion zone 3, a main coal-fired powder pipeline 3A, a reburning zone 4, a reburning pulverized coal pipeline 4A, C4, a feeding pipe, a decomposing furnace, a first raw material inlet 5, a C4 feeding pipe, a decomposing furnace, a second raw material inlet 6, a cement rotary kiln 7, a tertiary air inlet 8, an overfire air inlet 9, a main steam pipeline 10, a steam pressure stabilizing tank 11, a steam flow metering device 12, a reduction zone saturated steam catalytic burner 13, a reburning zone saturated steam catalytic burner 14, a C5 outlet 15, a decomposing furnace 16, an overfire zone 17, an electric three-way valve 18, a catalyst spray gun 19, a powder denitration agent conveying device 20, a storage bin 21, a material level meter 22, an activation hopper 23, a safety valve 24, a pneumatic arch breaker 25, a metering 26, a pneumatic gate valve 27, a gas-solid separator 28, a pressure feeder 29, a Roots blower 30, a feeder 31, weighing screw conveyor 32, feed inlet 33, vibrator 34, discharge pipe 35, tank car 36.
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, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.
As shown in figure 1, the invention provides an ultra-low emission denitration device for an ERDIII cement plant, which comprises a decomposing furnace and a powder denitration agent conveying device, wherein a secondary air inlet is arranged at the bottom of the decomposing furnace and is connected with a cement rotary kiln, and a decomposing furnace 16 comprises a reduction zone 2, a main combustion zone 3, a reburning zone 4 and a burnout zone 17 from bottom to top.
The reduction zone 2 is provided with a reduction zone saturated steam catalytic burner 13, the reburning zone 4 is provided with a reburning zone saturated steam catalytic burner 14, the reduction zone saturated steam catalytic burner 13 and the reburning zone saturated steam catalytic burner 14 are connected with a steam flow metering device 12, the steam flow metering device 12 is connected with a steam pressure stabilizing tank 11, and the steam pressure stabilizing tank 11 is connected with a main steam pipeline 10. The steam flow metering device 12 is internally provided with an intelligent vortex shedding flowmeter, a temperature transmitter and a pressure transmitter, and is used for monitoring the flow, the temperature and the pressure of steam in a steam pipeline in real time on line, realizing remote transmission in a central control system and facilitating observation.
The reducing area 2 is connected with a reducing pulverized coal pipeline 2A, the main combustion area 3 is connected with a main coal-fired pulverized coal pipeline 3A, the reburning area 4 is connected with a reburning pulverized coal pipeline 4A, and wear-resistant ceramic electric valves are arranged on the reducing pulverized coal pipeline 2A, the main coal-fired pulverized coal pipeline 3A and the reburning pulverized coal pipeline 4A, so that the coal feeding proportion can be automatically adjusted according to the requirement of central control operation, and the normal operation of the temperature and the kiln condition of the decomposing furnace is ensured.
The main burning zone 3 is provided with a tertiary air inlet 8, the burnout zone 4 is provided with a burnout air inlet 9, and the tertiary air inlet 8 and the burnout air inlet 9 are communicated with a cooler of the rotary cement kiln 7.
The discharging pipe of the powder denitration agent conveying device 20 is connected with a denitration agent spray gun 19, the denitration agent spray gun 19 is connected with the reburning area 4, C5 is arranged at the joint of the decomposing furnace 16 and the rotary cement kiln 7, 2C 5 are arranged and piled on two sides of the decomposing furnace 16, C5 is a fifth-stage preheating separator, an SNCR spray gun is arranged at the outlet 15 of the C5, and the SNCR spray guns are uniformly arranged on the circumferential wall surface of the outlet 15 of the C5. The burnout zone 4 is communicated with the C5, and an intelligent electromagnetic flow meter is arranged on the SNCR spray gun for controlling the flow of the sprayed ammonia. The content of nitrogen and oxygen compounds in the flue gas treated by the decomposing furnace 16 may still exceed the standard, and residual nitrogen and oxygen compounds can be further removed by arranging an SNCR spray gun.
The main combustion area 3 is provided with a C4 blanking pipe which enters a first raw material inlet 5 of the decomposing furnace, the reduction area 2 is provided with a C4 blanking pipe which enters a second raw material inlet 6 of the decomposing furnace, C4 is a fourth-stage preheating separator, and an electric three-way valve 18 is arranged in a C4 blanking pipe. Raw materials enter a first raw material inlet 5 of the decomposing furnace through a C4 discharging pipe, a second raw material inlet 6 of the decomposing furnace enters the decomposing furnace 16 through a C4 discharging pipe, heat emitted by burning of coal powder is enabled to be fully absorbed by the raw materials, an electric three-way valve 18 is arranged in the C4 discharging pipe and used for distributing the materials and can be controlled to operate in the middle, automatic distribution can be achieved, the decomposition rate of the raw materials is improved while high-efficiency denitration is achieved, the quality of kiln conditions is improved, the faster the heat absorption rate of the raw materials is, the more favorable the burning of the coal powder is, the temperature in the decomposing furnace 16 can be balanced, and the generation of a high-temperature area in the decomposing.
The discharging pipe of powder denitration agent conveyor 20 is connected with denitration agent spray gun 19, and denitration agent spray gun 19 is connected with reburning zone 4, and in this embodiment, 4 denitration agent spray guns 19 are set up, and evenly distributed in reburning zone 4. Powder denitration agent is introduced above the reburning zone 4, so that the ammonia-nitrogen ratio is reduced, nitrogen oxides are efficiently removed, the emission concentration of the nitrogen oxides is obviously reduced, and the escape of ammonia is reduced.
As shown in fig. 2, the powder denitration agent conveying device comprises a storage bin 21, a material level meter 22, an activation hopper 23, a safety valve 24, a pneumatic arch breaker 25, a metering feeder 26, a pneumatic gate valve 27, a gas-solid separator 28, a pressure transmitter 29, a roots blower 30, a feeder 31, a weighing screw conveyor 32, a vibrator 34 and a discharge pipe 35. The stock bin 21 comprises a cylindrical section and a conical section which are sequentially arranged from top to bottom, and the pneumatic arch breaking devices 25 are arranged to be multiple and located on different height positions of the side wall of the cylindrical section of each pneumatic arch breaking device 25. The vibrator 34 is disposed on the side wall of the conical section. The lateral wall of feed bin 21 is provided with 3 charge level indicator 22, and 3 charge level indicator 22 set up respectively in the upper portion of cylinder section, the junction of cylinder section and circular cone section, the lower part of circular cone section. The whole stainless steel material of feed bin 21, the pyramis sets up fluidization plate, introduces simultaneously and helps a class wind, prevents that the powder from hardening at the in-process of unloading, guarantees that the unloading is smooth and easy.
The top end of the storage bin 21 is provided with a feeding hole 23, and the lower end of the storage bin is communicated with a conical activation hopper 23. The activating hopper 23 adopts an integrated structure without welding seams, and the smoothness of blanking is ensured. The lower part of the activation hopper 23 is provided with a pneumatic gate valve 27, the lower end of the activation hopper 23 is communicated with a metering feeder 26, the lower end of the metering feeder 26 is communicated with a weighing screw conveyer 32, the lower end of the weighing screw conveyer 32 is communicated with a gas-solid separator 28, the lower end of the gas-solid separator 28 is communicated with a feeder 31, the left side of the feeder 31 is communicated with an air outlet of a Roots blower 30, a pressure transmitter 29 is arranged between the Roots blower 30 and the feeder 31, a discharge pipe 35 on the right side of the feeder 31 is communicated with a decomposing furnace 16, and the Roots blower 30.
The powder denitration agent conveying device of the cement plant of the embodiment is controlled by an electric automatic control system to operate. In the starting process of the system, the blanking amount is directly given, the automatic starting is clicked, the whole system can automatically start the Roots blower 30, the gas-solid separator 28, the weighing screw conveyor 32, the metering feeder 26, the gate valve 27 and the vibrator 34 in sequence according to a set equipment starting program, the equipment starting clearance is delayed, each equipment is ensured to be completely started, the system is accurately adjusted according to the set blanking amount after being started, and the flow conveying stability is ensured. When the system needs to be stopped, the system stops automatically, the vibrator 34, the gate valve 27, the metering feeder 26, the weighing screw conveyor 32, the gas-solid separator 28 and the Roots blower 30 are closed in sequence in a delayed mode, the fact that the excess materials are discharged completely is determined, the device is completely empty, and the operation is simple and convenient.
The invention provides an ultra-low emission denitration process method for an ERDIII cement plant, which comprises the following steps: the pulverized coal 1 delivered from the pulverized coal bunker is divided into three pipelines (a reducing pulverized coal pipeline 2A, a main coal-fired pulverized coal pipeline 3A and a reburning pulverized coal pipeline 4A) and enters a decomposing furnace 16, and a reducing area 2, a main burning area 3 and a reburning area 4 (the pulverized coal 1 is divided into the three pipelines to reduce the pulverized coal pipeline 2A, the main coal-fired pulverized coal pipeline 3A and the reburning pulverized coal pipeline 4A and respectively enters the reducing area 2, the main burning area 3 and the reburning area 4 of the decomposing furnace 16) are respectively established in the decomposing furnace 16 from bottom to top. The coal powder in the reduction zone 2 is mainly used for building the reduction zone 2 in the cone part of the decomposing furnace 16 and converting nitrogen oxides generated by the combustion of the coal powder at the kiln head and the passing of high-temperature flue gas through the cement rotary kiln 7. The coal powder in the main combustion area 3 is contacted with high-temperature secondary air from a cement rotary kiln 7 and then begins to combust to release heat, and the oxygen supplemented through a tertiary air inlet 8 ensures that the main combustion coal powder is fully combusted, thereby ensuring the decomposition efficiency of raw materials. The pulverized coal in the reburning zone 4 contacts with the flue gas generated by the combustion of the pulverized coal in the main burning zone 3 to produce a reducing atmosphere (a second reducing zone is formed in the middle of the decomposing furnace 16) and converts the nitrogen oxides generated by the rest of the reducing zone 2 and the main burning zone 3. Meanwhile, in order to ensure the sufficient combustion of the reburning pulverized coal, a stream of over-fire air is introduced into the decomposing furnace 16 from the over-fire air inlet 9 to establish an over-fire area 17 above the reburning pulverized coal, so as to ensure the sufficient combustion of the reburning pulverized coal, improve the temperature of the furnace and improve the decomposition rate of raw materials. Saturated steam is introduced into a steam pressure stabilizing tank 11 through a main steam pipeline 10 of a plant area, then a steam flow metering device 12 is arranged at an outlet of the steam pressure stabilizing tank 11 and respectively enters a reduction zone saturated steam catalytic combustor 13 and a reburning zone saturated steam catalytic combustor 14 so as to enter a reduction zone 2 and a reburning zone 4 which are built in a decomposing furnace 16, a catalyst is arranged in the combustor, the saturated steam is in contact with and mixed with pulverized coal and generates water-gas reaction through the action of the catalyst to generate CO and H2Reducing NO; denitration agent spray guns 19 (4 are uniformly distributed) are respectively arranged in the reburning zone 4, the denitration agent spray guns 19 are communicated with a discharge pipe 20, the discharge pipe 20 is connected with a powder denitration agent conveying device, and a denitration catalyst entering the reburning zone 4 is catalytically cracked into small molecular groups at the high temperature of 900-1100 DEG CThe catalyst has reducing properties and promotes the following reaction. The denitration reaction is carried out by taking the denitration catalyst as a reducing agent at the high temperature of 900-1100 ℃: various reductive small-molecule free radical groups H generated by organic component decomposition2H, c, and cahb. Wherein the denitration performance of the intermediate CxHy is optimal. The transition metal composite oxide of iron can not only promote the decomposition of organic molecules into small molecular CaHb, but also promote the reaction of the small molecular CaHb and NOx, and prevent the CaHb from being excessive and O2And (4) reacting.
FIG. 3 is a schematic diagram showing the relationship between the ammonia-nitrogen ratio and the denitration efficiency of the SNCR system of the present invention. As shown in figure 3, the ammonia nitrogen ratio of the traditional selective non-catalytic reduction denitration by SNCR is designed to be 1-1.5. In the ultra-low emission denitration technology of the ERDIII cement plant, ammonia water is sprayed after 20-40% of nitrogen oxides are removed in a reburning system. Therefore, compared with the existing process for controlling nitrogen oxides in combustion, the ultra-low emission denitration process of the ERDIIII cement plant has higher denitration efficiency, the consumption of reducing agents required by control after combustion is greatly reduced, the ammonia nitrogen ratio is designed to be 0-0.8, the possibility of ammonia escape is reduced from the source, and the ammonia escape can be controlled to be 6ppm (4.55 mg/m)3) Within.
The invention adds the denitrifier on the ERD + saturated steam catalytic combustion device, can greatly reduce the using amount of ammonia water, achieves the aim of ultralow emission, and meets the aims of energy conservation, environmental protection and safe production of cement plants.
Although the present invention has been described in detail with respect to the above embodiments, it will be understood by those skilled in the art that modifications or improvements based on the disclosure of the present invention may be made without departing from the spirit and scope of the invention, and these modifications and improvements are within the spirit and scope of the invention.
Claims (8)
1. An ultra-low emission denitration device of an ERDIII cement plant is characterized by comprising a decomposing furnace and a powder denitration agent conveying device, wherein a secondary air inlet is arranged at the bottom of the decomposing furnace, the secondary air inlet is connected with a cement rotary kiln, the decomposing furnace comprises a reduction zone, a main combustion zone, a reburning zone and a burnout zone from bottom to top, the reduction zone is provided with a reduction zone saturated steam catalytic burner, the reburning zone is provided with a reburning zone saturated steam catalytic burner, the reduction zone is connected with a reduction coal powder pipeline, the main combustion zone is connected with a main coal powder pipeline, the reburning zone is connected with a reburning coal powder pipeline, the main combustion zone is connected with tertiary air, the burnout zone is connected with burnout air, a discharge pipe of the powder denitration agent conveying device is connected with a denitration agent spray gun, the denitration agent spray gun is connected with the reburning zone, and the joint of the decomposing furnace and the cement rotary kiln is provided with C5, the C5 is a fifth-stage preheating separator, an SNCR spray gun is arranged at the outlet of the C5, and the burnout zone is communicated with the C5.
2. The ERDIII cement plant ultra-low emission denitration device as claimed in claim 1, wherein said powder denitration conveyor comprises a storage bin, an activation hopper, a pneumatic gate valve, a metering feeder, a weighing screw conveyor, a gas-solid separator, a feeder, a Roots blower and a discharge pipe, the top end of said storage bin is provided with a feed inlet, the lower end of said storage bin is communicated with the top end of said activation hopper, the bottom end of said activation hopper is communicated with the inlet end of said metering feeder, a pneumatic gate valve is arranged between said activation hopper and said metering feeder, the outlet end of said metering feeder is communicated with the inlet end of said weighing screw conveyor, the outlet end of said weighing screw conveyor is communicated with said gas-solid separator, said gas-solid separator is communicated with said feeder, said feeder is communicated with said discharge pipe, one end of said discharge pipe is connected with said Roots blower, the other end is connected with a decomposing furnace, and a pneumatic arch breaking device and a vibrator are arranged on the side wall in the storage bin.
3. The ERDIII cement plant ultra-low emission denitration apparatus as claimed in claim 2, wherein said denitration agent injection lance is provided in a plurality and uniformly distributed in said reburning zone.
4. The ERDIII cement plant ultra-low emission denitration apparatus as claimed in claim 2, wherein a pressure transmitter is provided on said tapping pipe, said pressure transmitter being provided between said roots blower and said feeder.
5. The ultra-low emission denitration device of claim 1, wherein said main combustion zone is provided with a C4 feeding pipe into a first raw material inlet of a decomposing furnace, said reduction zone is provided with a C4 feeding pipe into a second raw material inlet of the decomposing furnace, said C4 is a fourth-stage preheating separator, and said C4 feeding pipe is provided with an electric three-way valve.
6. The ERDIII cement plant ultra-low emission denitration apparatus as claimed in claim 1, wherein said primary combustion zone is provided with a tertiary air inlet, said burnout zone is provided with a burnout air inlet, and said tertiary air inlet and said burnout air inlet are communicated with a cooler of said rotary cement kiln.
7. The ERDIII cement plant ultra-low emission denitration device of claim 1, wherein said reduction zone saturated steam catalytic burner, said reburning zone saturated steam catalytic burner are connected to a steam flow meter, said steam flow meter is connected to a steam surge tank, and said steam surge tank is connected to a main steam pipeline.
8. The ERDIII cement plant ultra-low emission denitration device as claimed in claim 1, wherein said C5 is 2 and stacked on both sides of said decomposing furnace.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110218584A (en) * | 2019-06-06 | 2019-09-10 | 上海三融环保工程有限公司 | The cement plant ERDIII minimum discharge denitrification apparatus and process |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110218584A (en) * | 2019-06-06 | 2019-09-10 | 上海三融环保工程有限公司 | The cement plant ERDIII minimum discharge denitrification apparatus and process |
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