CN211358316U - Low-sulfur flue gas dry desulfurization denitration dust collector in cement kiln tail - Google Patents
Low-sulfur flue gas dry desulfurization denitration dust collector in cement kiln tail Download PDFInfo
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Abstract
The utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail, includes: the cement kiln, the decomposing furnace, the suspension preheater and the cooling device are connected in sequence; the desulfurization tower is connected with the flue gas outlet of the cooling device through an air inlet pipeline, and is a circulating fluidized bed dry-method desulfurization tower with a low-density low bed layer and without water spraying; the air inlet pipeline is provided with a high-temperature fan and is respectively connected with the raw material mill, the desulfurizer bin and the smoke dust returning device; the flue gas inlet of the dust remover is connected with the flue gas outlet of the desulfurizing tower, and the byproduct outlet of the dust remover is communicated with the air inlet pipeline through a flue gas returning device and is connected with the raw material warehouse through a byproduct conveying device; the medium-temperature SCR denitration device is characterized in that a flue gas inlet is connected with a flue gas outlet of the dust remover, a waste heat boiler and a draught fan are sequentially arranged on a gas outlet pipeline of the medium-temperature SCR denitration device, and purified gas is discharged through a chimney. The dry desulfurization, denitrification and dust removal device can remove multi-component pollutants in a synergistic manner while performing efficient desulfurization, denitrification and dust removal, does not need corrosion prevention, zero wastewater discharge and transparent chimney discharge, and can stably run for a long time.
Description
Technical Field
The utility model relates to a SOx/NOx control handles technical field, and more specifically says, relates to a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail.
Background
The cement kiln is a main source for discharging smoke pollutants in the cement industry, and the combustion of pulverized coal and clinker calcination in the cement kiln can generate a large amount of smoke accompanied by dust particles and SO2、NOxAnd the discharge of pollutants such as fluoride and the like. The trace heavy metal elements can be brought into the cement by adopting the traditional raw fuelIn kilns, alternative raw fuel applications and co-disposal of waste also introduce a certain amount of heavy metal elements. Under a certain concentration limit value, most heavy metal elements can be solidified in cement clinker, cement hydration products and formed cement slurry have good solidifying and sealing effects on the heavy metal elements, but mercury, arsenic, selenium and other heavy metals are easy to volatilize, and chromium is easy to dissolve out. In addition, Persistent Organic Pollutants (POPs) may also be generated during the high temperature calcination process of the cement kiln, and the POPs generated by the cement kiln are mainly dioxin-like substances. Recently, part of local governments have set more strict policies than national standards to limit the unit emission and total emission NOxThe emission was 50mg/Nm3、SO2The emission was 35mg/Nm3Dust emission of 5mg/Nm3. By adopting the flue gas circulating fluidized bed semi-dry desulfurization process, various pollutants such as acid gas, heavy metal, dioxin and the like can be removed in a synergistic manner while ultralow emission is realized. According to the data of the national cement technology exchange meeting at the end of 2017, 95% of sulfur emission of about 1700 novel dry-process cement production lines in China is medium-low sulfur, namely the concentration is 1000mg/Nm3Below, and mostly at 500mg/Nm3The following. If the wet desulphurization device is adopted, although the ultra-low emission can be easily realized, the one-time investment and the operation cost are higher, and the method needs a waste water treatment system to specially treat the highly polluted wet desulphurization waste water; can not effectively remove SO3Submicron aerosol particles; white smoke plume, blue smoke plume and chimney rain are common at the chimney port after desulfurization; the flue gas is saturated wet flue gas which is strong acid, the desulfurizing tower, the flue and the chimney need to be protected from corrosion, the investment and operation cost is high, the ignition risk is high during construction and maintenance, and the like.
The atmosphere department of environmental protection, namely the department of ministry of health, emphasizes on the 'discussion on clean development of coal and electricity and release of environmental impact in China' called Beijing in 2017, 9.19.: the non-electric industry is the key point of the current atmospheric pollution control. Compared with the continuous emission reduction of pollutants in the coal-electricity industry, the non-electricity industry has a larger and larger contribution ratio to the national pollution emission. In the beginning of 2018, China makes a three-year operation plan for implementing winning blue-sky guard operations, and starts ultra-low emission reconstruction in non-electric industries such as steel, coking and the like. Eyes of a userPreviously, the steel industry is actively developing ultra low emissions. As an important component of non-electricity industry, ultra-low emission of cement industry will be developed gradually, and some areas such as Tangshan, Zheng, etc. have begun to require NOx、SO2And the particulate matters need to meet the ultra-low emission requirement, and the national standard also has special emission requirements on HF, mercury and compounds thereof, ammonia and the like in the tail flue gas of the cement kiln. NO production line of cement kilnx、SO2The research on single technology of ultralow emission of harmful gas components is more, but the system solution and realization of ultralow emission are less, and the technology for purifying the tail flue gas multiple pollutants of the cement kiln is not popularized and applied on a large scale at present. The integrated technology for flue gas desulfurization and denitration simultaneously realizes desulfurization and denitration by using active carbon, ozone and the like in the same device, but has the defects of high investment, high operation cost of adsorbent, poor equipment reliability and higher requirement on reaction temperature window, and is difficult to meet the requirement of large-scale industrial use; the technology of industries such as steel, metallurgy, coking and the like is not suitable for the cement high-dust industry.
The tail flue gas of the cement kiln is generally characterized by comprising the following components: (1) the dust concentration of the flue gas is about 60-100 g/Nm3The adhesive has high viscosity and certain abrasiveness (the main components are calcium carbonate, silicon dioxide, magnesium carbonate and the like); (2) NO in flue gasxHas a high concentration of about 400 to 1500mg/Nm3On the left and right, the original nitrogen oxide content is high; (3) about 1700 novel dry-process cement production lines in China have 95 percent of middle-low sulfur emission, namely the concentration is 1000mg/Nm3Below, and mostly at 500mg/Nm3The following; (4) the air pollutants in the flue gas are various and complex in composition, including dust and NOx、SO2、CO2Heavy metals (mainly Hg, Pb, and Cd), organic pollutants, and the like; (5) the flue gas contains acidic gas with various components, and the flue gas at the outlet of the cement calcining rotary kiln contains SO2、NOxIn addition, HCl, HF, SO3And the like acid gases; (6) the temperature of the flue gas is high, the temperature of the outlet of the suspension preheater can reach 350-400 ℃ generally, and the temperature is reduced by a temperature reducing device (a temperature reducing device, a humidifying tower, a cold air valve and the like in a single or multiple combined mode)The temperature can be controlled to be 220-260 ℃; (7) the flue gas contains CO2When the greenhouse gas is equal, according to the preliminary knowledge, CO in the tail flue gas of the cement kiln2The smoke volume fraction is about 20-30%; (8) the cement kiln can be used for cooperatively treating solid wastes such as hazardous wastes, household garbage, sludge and the like.
At present, two measures are mainly adopted for the cement kiln tail flue gas desulfurization process at home and abroad: (1) self-excavation and diving, such as upgrading production equipment (adopting a vertical mill), adjusting process and operation and the like, are only suitable for low-sulfur and low-smoke-content projects with loose emission indexes; (2) a flue gas desulfurization device is added: a) dry reactant injection method: injecting slaked lime into a suitable location of the preheater system; b) hot raw material spraying method: feeding the decomposed raw meal into a cyclone dust collector between a primary cyclone and a secondary cyclone of a preheater system; c) spray drying desulfurization: slaking lime and spraying into a humidifying tower; d) the simple ammonia method comprises the following steps: ammonia water is sprayed into the preheater or the chimney or the exhaust gas main pipe; e) a composite desulfurization method: adding the desulfurization powder into the primary to tertiary preheaters from a kiln inlet hoister; the desulfurization water agent is atomized and sprayed into the ascending air pipe from the second-stage preheater to the first-stage preheater; the five methods belong to simple desulfurization processes, have low investment, high operation cost, low desulfurization efficiency and unstable effect, are only suitable for low-sulfur and low-smoke-content projects with loose emission indexes, and cannot meet the requirement of ultralow emission; f) limestone-gypsum method: the method can realize SO by adding a wet desulphurization device2The method has a waste water treatment system to specially treat the highly polluted wet desulphurization waste water; can not effectively remove SO3Submicron aerosol particles; white smoke plume, blue smoke plume and chimney rain are common at the chimney port after desulfurization; the flue gas is saturated wet flue gas which is strong acid, the desulfurizing tower, the flue and the chimney need to be protected from corrosion, the investment and operation cost is high, the ignition risk is high during construction and maintenance, and the like.
The cement kiln denitration technology mainly comprises the following steps: and adopting low-nitrogen combustors, low-nitrogen combustion technologies (including low-nitrogen coal injection pipes, air staged combustion and fuel staged combustion), SNCR and SCR, low-temperature oxidation and other denitration technologies. At present, the low-nitrogen combustion and SNCR technology is basically used in the domestic cement industry, and NO discharged from a suspension preheater can be ensuredxEmission control at 320mg/Nm3The following. When intelligent control is adopted to form high-efficiency SNCR, NO can be achievedxDischarge 100-150 mg/Nm3But the ammonia escape is large and can not meet the standard requirement of national ammonia escape; when NO is requiredxEmission is 100mg/Nm3In the following, NO is added with the amount of ammonia waterxLittle or little reduction in emission values, ammonia and NOxThe reaction efficiency is sharply reduced, and a large amount of ammonia water forms ammonia escape, so that the effect of the SCR catalyst is needed to reach 50mg/Nm3The following indexes also meet the control indexes of ammonia escape.
Chinese patent application publication No. CN109364741A discloses a cement kiln flue gas dry desulfurization and high-dust SCR denitration device and process, the process flow of which is: the flue gas to be purified firstly enters an SCR device, is subjected to high-temperature SCR denitration, is thrown into an air inlet pipeline of a bag-type dust remover through a desulfurizer throwing device arranged in the air inlet pipeline of a high-temperature fan for desulfurization, is subjected to bag-type dust removal, and is discharged into a chimney through a draught fan. However, the above technical solutions have the following disadvantages: (1) the problems of catalyst poisoning and blockage and low denitration efficiency; because flue gas directly advances SCR device earlier among this technical scheme belongs to the high dust and arranges, and the flue gas temperature is high, and the dust content is high, easily leads to catalyst poisoning deactivation and jam, and life is short, still easily causes the emergence of the operation of denitrification facility and maintenance cost high scheduling problem. (2) Downstream equipment plugging corrosion problems; because the downstream of the SCR denitration device arranged at the position is provided with facilities such as a waste heat power generation boiler, if the ammonia escape of the SCR denitration system is improperly controlled, the problems of blockage, corrosion, reduced heat efficiency and the like of the cooling device are easily caused. (3) The desulfurizer is sprayed into the gas inlet pipeline of the bag-type dust collector, the efficiency is low, the desulfurization effect is unstable, the bag-type dust collector is only suitable for low-sulfur low-smoke-content projects under the condition of loose emission indexes, and the ultralow emission requirement cannot be met.
Chinese patent application publication No. CN110075680A discloses a desulfurization, denitrification and dedusting ultra-low emission process and system for producing cement from low sulfur raw material, wherein the process flow is as follows: the waste gas generated at the kiln tail is collected by a dust collector at the kiln tail and then passes through smokeAnd (3) gas blending, namely raising the temperature of the mixed flue gas to 80-150 ℃, enabling the mixed flue gas to enter a low-temperature SCR denitration reactor for denitration, then enabling the mixed flue gas to enter a wet desulfurization tower for desulfurization, and then sending the mixed flue gas into a kiln tail chimney through an exhaust fan to be exhausted into the atmosphere. However, the above technical solutions have the following disadvantages: (1) the low-temperature catalyst is adopted, the actual operation performance is not achieved at home, the number of manufacturers capable of producing the catalyst is extremely small, the price is high, the investment cost is high, and the technical difficulty is high. (2) Compared with medium-high temperature catalysts, the catalyst volume number is increased, and the pressure loss is large. (3) The wet desulphurization is adopted, and a wastewater treatment system is required to specially treat the highly polluted wet desulphurization wastewater; can not effectively remove SO3Submicron aerosol particles; white smoke plume, blue smoke plume and chimney rain are common at the chimney port after desulfurization; the flue gas is saturated wet flue gas which is strong acid, the desulfurizing tower, the flue and the chimney need to be protected from corrosion, the investment and operation cost is high, the ignition risk is high during construction and maintenance, and the like.
Chinese patent application publication No. CN110052141A discloses a desulfurization, denitrification and dedusting ultra-low emission process and system for producing cement from high-sulfur raw materials, wherein the process flow is as follows: the waste gas generated at the kiln tail is firstly pre-dusted and then enters a semi-dry desulfurization tower for desulfurization, the flue gas from the semi-dry desulfurization tower is finely dusted, meanwhile, the kiln head residual air is led into the kiln tail and is mixed with the flue gas from the fine dust collector after passing through a kiln head dust collector and a kiln head draught fan on a kiln head residual air bypass pipeline, the mixed flue gas is sent into a low-temperature SCR denitration reactor for denitration by a relay fan, and then is sent into a kiln tail chimney by an exhaust fan and is exhausted into the atmosphere. However, the above technical solutions have the following disadvantages: (1) the low-temperature catalyst is adopted, the actual operation performance is not achieved at home, the number of manufacturers capable of producing the catalyst is extremely small, the price is high, the investment cost is high, and the technical difficulty is high. (2) Compared with medium and high temperature catalysts, the catalyst volume is increased, and the pressure loss is large.
In conclusion, the development of the low-sulfur flue gas dry desulfurization, denitrification and dust removal device in the tail of the cement kiln has very important significance.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model aims at providing a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail can be in high-efficient SOx/NOx control dust removal, can in coordination desorption HCl, HF, dioxin, multicomponent pollutants such as heavy metal, and need not anticorrosive, zero wastewater discharge, chimney discharge transparent, simultaneously can long-term steady operation.
The utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail, include:
the cement kiln, the decomposing furnace, the suspension preheater and the cooling device are connected in sequence;
the air inlet pipeline is connected with a flue gas outlet of the cooling device; the air inlet pipeline is provided with a high-temperature fan and is respectively connected with the raw material mill, the desulfurizer bin and the smoke dust returning device; the desulfurizing tower is a circulating fluidized bed dry-method desulfurizing tower with a low-density low bed layer and without spraying water;
the flue gas inlet is connected with the flue gas outlet of the desulfurizing tower; a byproduct outlet of the dust remover is communicated with the air inlet pipeline through the smoke dust return device and is connected with the raw material warehouse through a byproduct conveying device;
the flue gas inlet is connected with the flue gas outlet of the dust remover; the medium-temperature SCR denitration device is provided with an air outlet pipeline; the gas outlet pipeline is sequentially provided with a waste heat boiler and a draught fan, and purified gas is discharged through a chimney.
Preferably, the cooling device comprises one or more of a humidifying tower, a waste heat boiler and a cold air valve.
Preferably, the dust remover comprises one or two of an electric bag composite dust remover and a bag-type dust remover.
Preferably, the smoke dust return device comprises one or more of an air chute, a pneumatic conveying bin pump, a zipper machine, a bucket elevator and a belt conveyor.
Preferably, the byproduct conveying device comprises one or more of a pneumatic conveying bin pump, a zipper machine, a bucket elevator and a belt conveyor.
The utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail, include: cement connected in sequenceThe device comprises a kiln, a decomposing furnace, a suspension preheater and a cooling device; the air inlet pipeline is connected with a flue gas outlet of the cooling device; the air inlet pipeline is provided with a high-temperature fan and is respectively connected with the raw material mill, the desulfurizer bin and the smoke dust returning device; the desulfurizing tower is a circulating fluidized bed dry-method desulfurizing tower with a low-density low bed layer and without spraying water; the flue gas inlet is connected with the flue gas outlet of the desulfurizing tower; a byproduct outlet of the dust remover is communicated with the air inlet pipeline through the smoke dust return device and is connected with the raw material warehouse through a byproduct conveying device; the flue gas inlet is connected with the flue gas outlet of the dust remover; the medium-temperature SCR denitration device is provided with an air outlet pipeline; the gas outlet pipeline is sequentially provided with a waste heat boiler and a draught fan, and purified gas is discharged through a chimney. Compared with the prior art, the utility model provides a dry process SOx/NOx control dust collector can be in high-efficient SOx/NOx control dust removal, can remove multicomponent pollutants such as HCl, HF, dioxin, heavy metal in coordination, and need not anticorrosive, zero wastewater discharge, chimney discharge transparent, simultaneously can long-term steady operation. Experimental result shows, the utility model provides a dry process SOx/NOx control dust collector can make the NO in the flue gasxControlled at 50mg/m3Hereinafter, SO2Controlled at 35mg/m3The smoke dust is controlled at 5mg/m3In the following, ultra-low emission of atmospheric pollutants is achieved.
In addition, the utility model provides a dry process SOx/NOx control dust collector adopts the medium temperature SCR denitration, need not to heat up the flue gas again, has saved a large amount of energy consumptions; meanwhile, the smoke dust by-products can be returned to the raw material warehouse for recycling; and this dry process SOx/NOx control dust collector has reduced the desulfurizing tower height by a wide margin, has effectively reduced the filter area of dust remover, and the dust remover can utilize original tail dust remover, and the flue gas resistance is little, and the system is simple, and the power consumption is low, and the middle-high temperature flue gas after the purification can carry out heat recycle moreover, and whole investment and working costs are lower, have obvious technology and economic application advantage.
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FIG. 1 is the embodiment of the utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector's in cement kiln tail structure sketch map.
Detailed Description
The technical solution of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it should be understood that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail, include:
the cement kiln, the decomposing furnace, the suspension preheater and the cooling device are connected in sequence;
the air inlet pipeline is connected with a flue gas outlet of the cooling device; the air inlet pipeline is provided with a high-temperature fan and is respectively connected with the raw material mill, the desulfurizer bin and the smoke dust returning device; the desulfurizing tower is a circulating fluidized bed dry-method desulfurizing tower with a low-density low bed layer and without spraying water;
the flue gas inlet is connected with the flue gas outlet of the desulfurizing tower; a byproduct outlet of the dust remover is communicated with the air inlet pipeline through the smoke dust return device and is connected with the raw material warehouse through a byproduct conveying device;
the flue gas inlet is connected with the flue gas outlet of the dust remover; the medium-temperature SCR denitration device is provided with an air outlet pipeline; the gas outlet pipeline is sequentially provided with a waste heat boiler and a draught fan, and purified gas is discharged through a chimney.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a low sulfur flue gas dry desulfurization, denitrification and dust removal device in a cement kiln tail according to an embodiment of the present invention; the system comprises a cement kiln 1, a decomposing furnace 2, a suspension preheater 3, a cooling device 4, a high-temperature fan B1, a raw meal mill 5, a desulfurizer bin 6, a desulfurizing tower 7, a dust remover 8, a byproduct conveying device 9, a raw meal bin 10, a medium-temperature SCR denitration device 11, a waste heat boiler 12 and a draught fan B2.
The utility model discloses in, dry process SOx/NOx control dust collector includes cement kiln (1), dore furnace (2), suspension pre-heater (3), heat sink (4), high temperature fan (B1), raw meal grinds (5), desulfurizer storehouse (6), desulfurizing tower (7), dust remover (8), accessory substance conveyor (9), raw meal storehouse (10), medium temperature SCR denitrification facility (11), exhaust-heat boiler (12), draught fan (B2) and chimney.
In the utility model, the cement kiln (1), the decomposing furnace (2), the suspension preheater (3) and the cooling device (4) are connected in sequence; the cement kiln flue gas can follow cement kiln (1) and get into heat sink (4) after decomposing through dore furnace (2) in proper order, suspension pre-heater (3) preheat to cool down in heat sink (3) and in order to adapt to the temperature requirement of follow-up medium temperature SCR denitration, heat in the cement kiln flue gas can also be retrieved to the cooling in-process. The utility model discloses in, heat sink (4) are equipped with the exhanst gas outlet.
The utility model discloses in, heat sink (4) preferred include one or more combination in humidifying tower, exhaust-heat boiler and the cold blast valve, more preferred exhaust-heat boiler.
In the utility model, the desulfurizing tower (7) is used for desulfurizing the flue gas; the desulfurization tower (7) is a circulating fluidized bed dry-method desulfurization tower with low density and low bed layer and without water spraying, is suitable for a novel dry-method desulfurization process of the low bed layer, can greatly reduce the height of a straight pipe section of the desulfurization tower (7), can synchronously reduce the height of a dust remover (8), reduces the filtering area of the dust remover (8), and reduces the investment cost of a system; meanwhile, because the low-density low-bed layer is adopted, the overall resistance is small, and no water system exists, the overall power consumption is low; in addition, the smoke amount required by maintaining the low bed layer is relatively small, the fluctuation of the smoke amount when the cement raw material is ground on and off is within 20 percent, and the requirement can be met without setting clean smoke recirculation. In the preferred embodiment of the utility model, the automatic control system can meet the requirements of the temperature, the humidity and the SO when the raw material is started or stopped2Concentration and other working conditions change, namely, the cooling mode of one or more combinations of a humidifying tower, a waste heat boiler and a cold air valve is adopted by the front-stage cooling device (4) to be completely adapted, so that the average value of the pollutant concentration in hours is not overproof, and the system operation is stabilized.
In the utility model, the desulfurizing tower (7) is provided with an air inlet pipeline and a flue gas outlet; wherein, the air inlet pipeline is connected with a smoke outlet of the cooling device (4). The utility model discloses in, the air inlet pipeline is equipped with high temperature blower (B1) to link to each other with raw meal mill (5), desulfurizer storehouse (6) and smoke and dust returning charge device respectively.
The utility model discloses in, high temperature fan (B1) are used for providing the power of carrying for the flue gas to control the flue gas and carry out the velocity of flow that desulfurates in desulfurizing tower (7). The utility model discloses in, raw meal grinds (5) and is used for providing the flue gas that raw meal ground (5), make it with cement kiln flue gas in the inlet line joins. In the utility model, desulfurizer storehouse (6) is used for providing the desulfurizer. The utility model discloses in, the smoke and dust returning charge device is used for getting the smoke and dust accessory substance circulation that obtains after dust remover (8) remove dust and returns air inlet pipe way to reentrant desulfurizing tower carries out the desulfurization. The utility model discloses in, the smoke and dust returning charge device is preferred to include one or more combination in air chute, pneumatic conveying storehouse pump, zip fastener machine, bucket elevator and the belt conveyor, more preferably air chute.
In the utility model, the flue gas outlet is used for discharging the flue gas after desulfurization.
In the utility model, the dust remover (8) is used for removing dust from the desulfurized flue gas, collecting the smoke dust and unreacted materials (smoke dust by-products), and obtaining low-sulfur and low-dust flue gas; the dust remover (8) preferably comprises one or two combinations of an electric bag composite dust remover and a bag-type dust remover, more preferably the bag-type dust remover, and can utilize the original tail dust remover; the bag filter material of the bag-type dust collector is preferably P84 or PTFE.
In the utility model, the dust remover (8) is provided with a flue gas inlet, a byproduct outlet and a flue gas outlet; wherein, the flue gas inlet of the dust remover (8) is connected with the flue gas outlet of the desulfurizing tower (7).
In the utility model, the byproduct outlet of the dust remover (8) is communicated with the air inlet pipeline through the smoke dust returning device, so that a part (most) of smoke dust byproducts circulate back to the air inlet pipeline and then enter the desulfurizing tower for desulfurization; meanwhile, a byproduct outlet of the dust remover (8) is connected with the raw material warehouse (10) through a byproduct conveying device (9), so that the other part (small part) of the smoke and dust byproducts are conveyed to the raw material warehouse (10) through the byproduct conveying device (9) for further recycling.
In the utility model discloses, accessory substance conveyor (9) preferred include the pneumatic conveying storehouse pump, draw zipper machine, bucket elevator and belt conveyor in one or more combination, more preferably pneumatic conveying storehouse pump.
In the utility model, the flue gas outlet of the dust remover (8) is used for discharging low-sulfur and low-dust flue gas.
In the utility model, the medium-temperature SCR denitration device (11) is used for carrying out medium-temperature SCR denitration on low-sulfur and low-dust flue gas; the utility model discloses a medium temperature SCR denitration need not to heat up the flue gas again, has saved a large amount of energy consumptions. The utility model discloses in the preferred embodiment, medium temperature SCR denitrification facility (11) with dust remover (8) adopt integrated form design, sharing basis and steelframe, save the whole use amount that occupies area and equipment steel, and then reduce cost removes dust earlier simultaneously and then denitrates, can alleviate the poison of dust to the catalyst, and the reducing system blocks up and wearing and tearing, guarantees SCR device's long-term steady operation.
In the utility model, the medium-temperature SCR denitration device (19) is provided with a flue gas inlet and a gas outlet pipeline; wherein, the flue gas inlet of the medium-temperature SCR denitration device (19) is connected with the flue gas outlet of the dust remover (8).
The utility model discloses in, the gas outlet pipeline is equipped with exhaust-heat boiler (12) and draught fan (B2) in proper order to purify the gas through the chimney discharge. The utility model discloses in, exhaust-heat boiler (12) adopt the series connection that technical personnel familiar in this field are established ties or parallelly connected relation all can, the purpose carries out heat recovery to the well high temperature flue gas after the purification, reduces whole investment and working costs.
The utility model discloses in, draught fan (B2) are used for providing power to the transport of purified gas.
The utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector can carry out among the cement kiln tail integration technology of removing dust of SOx/NOx control, adoptsThe dry desulfurization tower of the circulating fluidized bed which uses a low-density low-bed layer and does not spray water, a dust remover and a medium-temperature SCR denitration device which are synchronously matched are used for realizing the treatment of low-sulfur flue gas in the tail of a cement kiln and enabling NO in the flue gas to be NOxControlled at 50mg/m3Hereinafter, SO2Controlled at 35mg/m3The smoke dust is controlled at 5mg/m3The ultra-low emission of atmospheric pollutants is realized; meanwhile, multi-component pollutants such as HCl, HF, dioxin, heavy metals and the like can be removed in a synergistic manner, the whole system does not need to be antiseptic, zero wastewater discharge is realized, and the chimney discharge is transparent; and the poison of dust to the catalyst can be reduced, the system blockage and abrasion are reduced, and the long-term stable operation of the SCR device is ensured.
The utility model also provides a dry process SOx/NOx control method suitable for cement kiln flue gas, adopt above-mentioned technical scheme dry process SOx/NOx control dust collector, including following step:
a) decomposing, suspending, preheating and cooling the cement kiln flue gas in sequence, then converging the cement kiln flue gas with the flue gas of a raw material mill, carrying out dry desulfurization under the action of a desulfurizing agent, and then removing dust to respectively obtain a smoke dust byproduct and low-sulfur and low-dust flue gas; wherein, one part of the smoke dust by-product is circularly subjected to the dry desulfurization, and the other part of the smoke dust by-product is conveyed to a raw material warehouse; the dry desulfurization Venturi velocity is 30-70 m/s, the straight pipe section velocity is 3-7 m/s, and the bed layer is 200-800 Pa;
b) carrying out medium-temperature SCR denitration on the low-sulfur and low-dust flue gas obtained in the step a), and recovering heat to obtain purified gas.
The utility model discloses at first preheat the cement kiln flue gas through decomposition, suspension in proper order and after the cooling, converge with the flue gas that raw ground to carry out the dry process desulfurization under the desulfurizer effect, remove dust again, obtain smoke and dust accessory substance and low sulfur low dust flue gas respectively.
The utility model discloses it is right the source of cement kiln flue gas does not have special restriction, adopt the cement kiln flue gas that technical personnel in the field are familiar with can. In the utility model, the SO of the flue gas of the cement kiln2The concentration is preferably 100mg/Nm3～1000mg/Nm3Namely the low-sulfur flue gas.
In the utility model, the decomposition process is carried out in a decomposing furnace (2) connected with a cement kiln (1); the suspension preheating process is carried out in a suspension preheater (3), and the suspension preheating temperature is preferably 350-400 ℃; the cooling process is carried out in a cooling device (4). In the utility model, the temperature of the cooling is preferably 220 ℃ to 260 ℃.
The utility model discloses in, cement kiln flue gas after decomposition, suspension preheat and cooling joins through the flue gas of high temperature positive blower (B1) with raw meal mill (5) to carry out dry desulfurization under the desulfurizer effect. In the present invention, the desulfurizing agent is preferably selected from slaked lime and/or carbide slag, and more preferably slaked lime. In the preferred embodiment of the present invention, the SO of the flue gas of the cement kiln2The concentration is 500mg/Nm3In the above, the desulfurizing agent is high-quality slaked lime with high activity and larger surface area. In the utility model, the desulfurizer is provided by a desulfurizer bin (6); the source of the desulfurizing agent is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used.
In the utility model, the dry desulphurization process is carried out in a desulphurization tower (7), and the desulphurization tower (7) adopts a circulating fluidized bed dry desulphurization tower with low density and low bed layer which does not spray water; wherein the flue gas and the desulfurizer are mixed and react in a low-density low-bed layer to remove SO in the flue gas2、SO3The flue gas purification system comprises acidic gaseous pollutants such as HCl and HF, and meanwhile, the action of the huge specific surface area of high-concentration alkaline solid particles in a circulating fluidized bed and an efficient mass and heat transfer environment are realized, no adsorbent is required to be added, almost all bivalent Hg, most of Hg and dioxin in the flue gas are absorbed and adsorbed and removed, and the standard discharge of heavy metals such as mercury and dioxin in the flue gas can be realized.
In the utility model, the Venturi velocity of dry desulfurization is preferably 30 m/s-70 m/s, the velocity of flow of straight pipe section is preferably 3 m/s-7 m/s, and the bed layer is preferably 200 Pa-800 Pa. In the utility model, SO is in the flue gas2The concentration is 500mg/Nm3In the following, the bed layer is preferably 200Pa to 500 Pa; when SO is contained in flue gas2The concentration is 500mg/Nm3In the above-mentioned time, the water-soluble polymer,the bed layer is preferably 500Pa to 800 Pa.
In the utility model, SO is in the flue gas after the dry desulfurization2The concentration is not more than 35mg/Nm3。
In the utility model, the dust removal process is carried out in the dust remover (8) to respectively obtain a smoke dust byproduct and low-sulfur and low-dust flue gas; wherein, one part of the smoke dust by-product is circularly subjected to the dry desulfurization, and the other part of the smoke dust by-product is conveyed to a raw material warehouse. In the preferred embodiment of the utility model, the cake layer material on the filter bag of the dust collector (8) also contains a certain amount of desulfurizer which can further absorb and remove SO in the flue gas while removing the flue gas dust2、SO3And NOx(ii) a A large amount of unreacted desulfurizer returns to the desulfurizing tower (7) from the lower end of the cloth bag through a smoke dust returning device for recycling, a small amount of byproducts which are completely reacted are sent to a raw material warehouse (10) through a byproduct conveying device (9), enter a suspension preheater and a decomposing furnace along with raw materials for oxidation, and finally enter a rotary kiln for solidification into cement clinker; the present invention is not limited to this.
In the present invention, the filtering wind speed for dust removal is preferably 1.2m/min or less, more preferably 1.05m/min or less.
In the utility model, the smoke concentration in the smoke after dust removal is not more than 5mg/Nm3。
Obtain behind the low sulphur low dust flue gas, the utility model discloses the low sulphur low dust flue gas that will obtain carries out the medium temperature SCR denitration, obtains the gas purification after the recovery heat.
The utility model discloses in, NO in the flue gas after medium temperature SCR denitrationxThe concentration is not more than 50mg/Nm3。
In the present invention, the temperature of the purified gas after heat recovery is preferably 80 to 100 ℃.
The utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail, include: the cement kiln, the decomposing furnace, the suspension preheater and the cooling device are connected in sequence; the air inlet pipeline is connected with a flue gas outlet of the cooling device; the air inlet pipeline is provided with a high-temperature fan and is divided intoIs respectively connected with a raw material mill, a desulfurizer bin and a smoke dust returning device; the desulfurizing tower is a circulating fluidized bed dry-method desulfurizing tower with a low-density low bed layer and without spraying water; the flue gas inlet is connected with the flue gas outlet of the desulfurizing tower; a byproduct outlet of the dust remover is communicated with the air inlet pipeline through the smoke dust return device and is connected with the raw material warehouse through a byproduct conveying device; the flue gas inlet is connected with the flue gas outlet of the dust remover; the medium-temperature SCR denitration device is provided with an air outlet pipeline; the gas outlet pipeline is sequentially provided with a waste heat boiler and a draught fan, and purified gas is discharged through a chimney. Compared with the prior art, the utility model provides a dry process SOx/NOx control dust collector can be in high-efficient SOx/NOx control dust removal, can remove multicomponent pollutants such as HCl, HF, dioxin, heavy metal in coordination, and need not anticorrosive, zero wastewater discharge, chimney discharge transparent, simultaneously can long-term steady operation. Experimental result shows, the utility model provides a dry process SOx/NOx control dust collector can make the NO in the flue gasxControlled at 50mg/m3Hereinafter, SO2Controlled at 35mg/m3The smoke dust is controlled at 5mg/m3In the following, ultra-low emission of atmospheric pollutants is achieved.
In addition, the utility model provides a dry process SOx/NOx control dust collector adopts the medium temperature SCR denitration, need not to heat up the flue gas again, has saved a large amount of energy consumptions; meanwhile, the smoke dust by-products can be returned to the raw material warehouse for recycling; and this dry process SOx/NOx control dust collector has reduced the desulfurizing tower height by a wide margin, has effectively reduced the filter area of dust remover, and the dust remover can utilize original tail dust remover, and the flue gas resistance is little, and the system is simple, and the power consumption is low, and the middle-high temperature flue gas after the purification can carry out heat recycle moreover, and whole investment and working costs are lower, have obvious technology and economic application advantage.
To further illustrate the present invention, the following examples are given in detail.
Example 1
The structural schematic diagram of the low-sulfur flue gas dry desulfurization, denitrification and dust removal device in the cement kiln tail provided by the embodiment of the utility model is shown in figure 1; the system comprises a cement kiln 1, a decomposing furnace 2, a suspension preheater 3, a waste heat boiler 4, a high-temperature fan B1, a raw meal mill 5, a desulfurizer bin 6, a circulating fluidized bed dry desulfurization tower 7 with low density and low bed layers and without water spraying, a bag-type dust remover 8, a pneumatic conveying bin pump 9, a material bin 10, a medium-temperature SCR denitration device 11, a waste heat boiler 12 and a draught fan B2.
The connection relation of the dry desulfurization denitration dust removal device is as follows: the air outlet of the cement kiln (1) is connected to the air inlet of the decomposing furnace (2), the air outlet of the decomposing furnace (2) is connected to the air inlet of the suspension preheater (3), the air inlet of the waste heat boiler (4) is connected to the air outlet of the suspension preheater (3), the flue gas outlet of the waste heat boiler (4) is connected to the air inlet of the high temperature fan (B1), the high temperature fan (B1) is arranged on an air inlet pipeline, the air inlet pipeline is respectively connected with the discharge hole of the raw meal mill (5) and the discharge hole of the desulfurizer bin (6) and is communicated with the circulating fluidized bed dry-method desulfurization tower (7) which does not spray water on the low-density and low-bed layers, the flue gas outlet of the circulating fluidized bed dry-method desulfurization tower (7) which does not spray water on the low-density and low-bed layers is connected with the flue gas inlet of the bag-type dust remover (8), the byproduct outlet of the, the flue gas outlet of the bag-type dust collector (8) is connected with the flue gas inlet of the medium-temperature SCR denitration device (11), and the gas outlet pipeline of the medium-temperature SCR denitration device (11) is sequentially provided with a waste heat boiler (12) and an induced draft fan (B2) and discharges purified gas through a chimney.
The dry desulfurization, denitrification and dust removal integrated process for the cement kiln flue gas by adopting the dry desulfurization, denitrification and dust removal device has the following specific working processes:
1) the cement kiln tail flue gas is sequentially decomposed by a cement kiln (1) and a decomposing furnace (2) and preheated by a suspension preheater (3), the flue gas temperature is 350-400 ℃, and then the flue gas enters a waste heat boiler (4) for cooling, the flue gas temperature is reduced to 220-260 ℃, and then the flue gas is converged with the flue gas of a raw material mill (5) by a high temperature fan (B1), and enters a circulating fluidized bed dry-method desulfurization tower (7) with low density and low bed layer without spraying water together with a desulfurizing agent in a desulfurizing agent bin (6) for dry-method desulfurization, the Venturi flow rate is 30-70 m/s, and the straight pipe section flow rate is 3-7 m/s; then the dust is removed by a bag-type dust remover (8), and the filtering wind speed is less than or equal to 1.05m/min, so that a smoke by-product and low-sulfur and low-dust smoke are respectively obtained; most of the smoke dust byproducts return to a circulating fluidized bed dry-method desulfurization tower (7) with a low-density low bed layer without spraying water through an air chute for recycling, the dry-method desulfurization is carried out in a circulating mode, a small part of completely reacted byproducts are conveyed to a raw material warehouse (10) through a byproduct conveying device (9), enter a suspension preheater and a decomposing furnace along with raw materials for oxidation, and finally enter a rotary kiln for solidification into cement clinker.
2) The low-sulfur and low-dust flue gas is subjected to medium-temperature SCR denitration in a medium-temperature SCR denitration device (11), and SO in the flue gas2、NOxDust, SO3Multiple pollutants such as HF, HCl, mercury, dioxin and the like are efficiently and synergistically removed; the purified flue gas is subjected to waste heat recovery and utilization through a waste heat boiler (12), the temperature of the flue gas is reduced to 80-100 ℃, and the flue gas is discharged out of a chimney under the action of a draught fan (B2).
The embodiment 1 of the utility model relates to a technical parameter and corresponding technological effect as follows: the clinker produced by cement is 2500t/d, and the smoke gas amount is 250000Nm3H (dry standard), raw flue gas NOxThe concentration is about 400mg/Nm3，SO2The concentration is about 400mg/Nm3The bed of the circulating fluidized bed dry desulfurization tower (7) with low density and low bed without spraying water is controlled to be 450Pa, and Ca (OH) is used2The Ca/S is about 1.6-1.8, the height of the desulfurizing tower (7) and the dust remover (8) can be reduced by about 18m, the weight of the body and the steel frame of the desulfurizing tower (7) and the dust remover (8) can be reduced by about 180 tons, about 1373 cloth bags and bag cages are saved, the investment can be reduced by about 40% compared with the conventional dry desulfurizing and dust removing of a circulating fluidized bed, and if the original tail dust remover is utilized, the investment can be saved by more than 65%; moreover, the power consumption is saved by about 77kw/h only by a water system, the power consumption is saved by about 100kw/h by resistance, and the running cost can completely offset or even reduce the cost caused by the excessive consumption of the desulfurizer; the whole process flow is simple, the operation is simple and convenient, the operation is stable, and NO in the flue gas after the operationxControlled at 50mg/m3Hereinafter, SO2Controlled at 35mg/m3The smoke dust is controlled at 5mg/m3The ultra-low emission of atmospheric pollutants is realized, and SO can be removed cooperatively3、HF、HCl, mercury, dioxin and other pollutants, and no secondary pollution of waste water (slag) and no anticorrosive treatment. And the poison of dust to the catalyst can be reduced, the system blockage and abrasion are reduced, and the long-term stable operation of the SCR device is ensured.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (5)
1. The utility model provides a low sulfur flue gas dry process SOx/NOx control dust collector in cement kiln tail, includes:
the cement kiln, the decomposing furnace, the suspension preheater and the cooling device are connected in sequence;
the air inlet pipeline is connected with a flue gas outlet of the cooling device; the air inlet pipeline is provided with a high-temperature fan and is respectively connected with the raw material mill, the desulfurizer bin and the smoke dust returning device; the desulfurizing tower is a circulating fluidized bed dry-method desulfurizing tower with a low-density low bed layer and without spraying water;
the flue gas inlet is connected with the flue gas outlet of the desulfurizing tower; a byproduct outlet of the dust remover is communicated with the air inlet pipeline through the smoke dust return device and is connected with the raw material warehouse through a byproduct conveying device;
the flue gas inlet is connected with the flue gas outlet of the dust remover; the medium-temperature SCR denitration device is provided with an air outlet pipeline; the gas outlet pipeline is sequentially provided with a waste heat boiler and a draught fan, and purified gas is discharged through a chimney.
2. The dry desulfurization, denitrification and dust removal device according to claim 1, wherein the temperature reduction device comprises one or more of a humidifying tower, a waste heat boiler and a cold air valve.
3. The dry desulfurization, denitrification and dust removal device according to claim 1, wherein the dust remover comprises one or a combination of an electric bag composite dust remover and a bag-type dust remover.
4. The dry desulfurization, denitrification and dust removal device according to claim 1, wherein the smoke dust return device comprises one or more of an air chute, a pneumatic conveying bin pump, a zipper machine, a bucket elevator and a belt conveyor.
5. The dry desulfurization, denitrification and dust removal device according to claim 1, wherein the byproduct conveying device comprises one or more of a pneumatic conveying bin pump, a zipper machine, a bucket elevator and a belt conveyor.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112870930A (en) * | 2021-04-28 | 2021-06-01 | 潍坊国昌新材料有限公司 | Desulfurization and denitrification system based on cement flue gas |
| CN113332839A (en) * | 2021-04-25 | 2021-09-03 | 北京建筑材料科学研究总院有限公司 | Cement kiln flue gas desulfurization and denitrification coupling recycling system and method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113332839A (en) * | 2021-04-25 | 2021-09-03 | 北京建筑材料科学研究总院有限公司 | Cement kiln flue gas desulfurization and denitrification coupling recycling system and method |
| CN112870930A (en) * | 2021-04-28 | 2021-06-01 | 潍坊国昌新材料有限公司 | Desulfurization and denitrification system based on cement flue gas |
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