CN210159444U - Desulfurization, denitrification and dedusting ultra-low discharge system for producing cement by using high-sulfur raw materials - Google Patents
Desulfurization, denitrification and dedusting ultra-low discharge system for producing cement by using high-sulfur raw materials Download PDFInfo
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- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 134
- 230000023556 desulfurization Effects 0.000 title claims abstract description 125
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Abstract
The utility model discloses a desulfurization denitration dust removal ultralow discharge system of high sulphur raw materials production cement, this system includes cement clinker firing system, kiln tail high temperature blower, the grinding system, dust collector one, semi-dry desulfurization tower, dust collector two, low temperature SCR denitration reactor, kiln head dust collector and kiln head draught fan, the first order kiln tail preheater whirlwind section of thick bamboo gas outlet of kiln tail preheater, kiln tail high temperature blower, the grinding system, dust collector one, semi-dry desulfurization tower, dust collector two, the relay fan, low temperature SCR denitration reactor, the exhaust fan, kiln tail chimney links to each other in proper order and sets up, the cooler gas outlet, kiln head dust collector, kiln head draught fan links to each other in proper order and sets up, kiln head draught fan exit linkage dust collector two gas outlets. The utility model discloses an earlier semi-dry desulfurization low temperature SCR denitration again realizes the SOx/NOx control dust removal minimum emission of high sulphur raw materials production cement.
Description
Technical Field
The utility model relates to a flue gas treatment technical field especially relates to a SOx/NOx control dust removal minimum discharge system of high sulphur raw materials production cement.
Background
The national environmental protection policy is increasingly strict, and the atmospheric pollutant emission of the cement kiln and kiln tail waste heat utilization system in the heavy-spot region is particularly limited to NO respectively in the national standard GB 4915-2013' emission Standard of atmospheric pollutants for Cement industryx320mg/Nm3、SO2100mg/Nm320mg/Nm of particulate matter3. NO requirement in the second generation of cement technology standards introduced by the building materials AssociationxThe emission was 100mg/Nm3、SO2The emission was 50mg/Nm3Flour and flourDust emission is 10mg/Nm3. The recent part of local government has set more strict policy to limit the unit emission and the total emission NOxThe emission was 50mg/Nm3、SO2The emission was 35mg/Nm3Dust emission of 5mg/Nm3. The cement manufacturer increases new environment-friendly equipment, stops production or reduces production, has large market demand on desulfurization, denitrification and dedusting, is immature in related technical equipment, and has the phenomenon that one pollutant is used for replacing another pollutant.
Influence of SO2The discharged substances are mainly SO in limestone in the cement raw materials3The sulfur content of the local limestone resources in China Guangdong, Zhejiang, Anhui provinces and other provinces is higher, SO that the SO in the raw materials is higher3The content is more than 0.1 percent, and the content can reach 100mg/Nm by installing a desulfurization device3And (5) discharging requirements. When the sulfur content exceeds more than 0.3%, the emission of the whole system is greatly influenced, the reaction with ammonia water of an SNCR system is easy to generate equipment corrosion, and especially when the water content in raw fuel and air is large, the moisture content in flue gas is large, the equipment is easy to corrode, so that an optimal emission reduction scheme must be developed; in addition, when the sulfur content in the raw materials exceeds 1%, the influence on the strength of the clinker is generated, so that the emission reduction problem needs to be comprehensively considered when the high-sulfur raw materials are used for producing cement. The desulfurization adopts a desulfurizer injection method or a wet desulfurization process, the reaction efficiency of the injection method of the desulfurizer such as calcium oxide, calcium hydroxide or ammonia water is lower by about 20-30%, and the desulfurization proportion is about 50%; the reaction efficiency of the wet desulphurization technology is higher and reaches more than 90 percent, but the defects are that the white elimination problem exists, extra heating and other measures are needed, and in addition, if the wet desulphurization technology is adopted when the high-sulfur raw material is used for producing cement, SO2And derived small amounts of SO3The flue gas passes through all equipment, and the equipment is easy to corrode when the temperature is low after the flue gas reaches the kiln tail dust collector, and particularly, the equipment is easy to corrode by the generated ammonium bisulfate when the excess ammonia water sprayed by SNCR is encountered.
The factors influencing NOx emission are more, and can be divided into thermal nitrogen, fuel nitrogen and instant nitrogen in the generation principle, and the combustion of the rotary kiln and the decomposing furnace can generate NOx, so that almost all the NOx is generatedThe production line all relates to the denitration problem. The denitration measures mainly comprise a low-nitrogen combustor, a low-nitrogen self-denitration decomposing furnace or fractional combustion, SNCR and SCR. The low-nitrogen burner, the low-nitrogen self-denitration decomposition furnace or the staged combustion can reach the NOx emission of 300-3(ii) a The SNCR can reach the NOx emission of 150-3When intelligent control is adopted to form high-efficiency SNCR, the NOx emission can reach 100-3But the ammonia escape is large and can not meet the standard requirement of national ammonia escape; when NOx emissions are required to be at 100mg/Nm3When the ammonia water consumption is increased, the NOx emission value is hardly reduced or the reduction amplitude is very small, the reaction efficiency of the ammonia water and NOx is rapidly reduced, a large amount of ammonia water forms ammonia escape, and the ammonia escape can reach 50mg/Nm stably only under the action of an SCR catalyst3The following indexes also meet the control indexes of ammonia escape. However, the application of the SCR catalyst in a power plant is mature, a cement plant is different from the power plant, the conditions of dust, temperature, sulfur dioxide and the like are different, the service life of the catalyst is limited, the medium-temperature catalyst is easily blocked, the utilization of hot flue gas is negatively affected, the waste heat power generation amount is reduced, a high-temperature dust collector needs to be added, and the one-time investment is large. Therefore, the low-temperature SCR is the best route for solving denitration emission in cement production, and has the minimum influence on the arrangement and production operation of a previous workshop.
Cement kiln production line SO2、NOxThe single technology research of the ultra-clean emission of harmful gas components is more, but the system solution and the realization of the ultra-low emission are less, and the consideration of avoiding the generation of the ammonium bisulfate needs to avoid the excessive ammonia water and the SO2If the SCR is used in the wet desulphurization, the temperature of the flue gas at the outlet of the wet desulphurization is low, the moisture content is high, the low-temperature SCR device can be used only by heating to about 100 ℃, and the running cost of the system is high. A large number of production practices show that a scheme for comprehensively solving the problems of desulfurization, denitrification, dust removal and ultra-clean emission is needed, and the environmental protection index, the economic index and the stability of cement produced by high-sulfur raw materials are met.
The combined desulfurization and denitrification technology has the problems of high fixed investment, complex flow, complex operation, high operation and maintenance cost and the like. The integrated technology for flue gas desulfurization and denitration has more researches on simultaneously realizing desulfurization and denitration in the same device, such as activated carbon, ozone and the like, but has the defects of high operating cost of an adsorbent, poor equipment reliability and higher requirement on a 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. Therefore, the search for a process and a device with low cost and good removal effect has become a leading research direction in the field of air pollution control, and is always an effort by researchers in various countries.
In conclusion, based on the problems, the process and the system which can systematically solve the problems of cement production by high-sulfur raw materials and achieve desulfurization, denitrification, dedusting and ultra-clean emission of the cement kiln have important practical significance.
Disclosure of Invention
One of the purposes of the utility model is to provide a desulfurization, denitrification and dedusting ultra-low emission process for producing cement by using high-sulfur raw materials.
The utility model discloses a realize like this, a desulfurization denitration dust removal ultralow emission technology of high sulphur raw materials production cement, include following step:
s1, cement clinker sintering: the high-sulfur raw material is subjected to heat exchange with hot flue gas by a kiln tail preheater, then is fed into a decomposing furnace for decomposition, is calcined in a rotary kiln, and then enters a cooling machine for cooling to obtain cement clinker; the cement clinker sintering simultaneous sintering system carries out self-denitration, SNCR and self-desulfurization of the decomposing furnace, and the self-denitration and SNCR of the decomposing furnace control the NOx in the flue gas discharged from the kiln tail preheater within the lowest NOx emission range without ammonia escape, SO2The discharge concentration is 1000-2500mg/Nm3；
S2, coarse dust removal and semi-dry desulfurization: waste gas generated at the tail of the kiln enters a grinding system as a drying heat source from a cyclone cylinder of a first-stage kiln tail preheater of a kiln tail preheater through a kiln tail high-temperature fan to be utilized and then enters a dust collector I for coarse dust collection, if the grinding system stops, the kiln tail waste gas directly enters the dust collector I through a bypass of the grinding system, and the concentration of dust at a gas outlet of the dust collector is controlled to be 2g/Nm3Then, the flue gas enters a semi-dry desulfurization tower for desulfurization, so that the flue gas out of the semi-dry desulfurization towerSO in gas2Emission control at 35mg/Nm3The temperature of the flue gas is 65-100 ℃, and the humidity is 10-15%;
s3, fine dust removal and desulfurization ash treatment: the flue gas from the semi-dry desulfurization tower is subjected to secondary fine dust collection by a dust collector, and the dust concentration of the secondary gas outlet of the dust collector is controlled to be 5mg/Nm3The following; and one part of the desulfurized ash collected by the second dust collector circularly enters a semi-dry desulfurization tower, the other part of the desulfurized ash is sent to a kiln tail decomposing furnace for oxidation, and finally the desulfurized ash enters the rotary kiln along with raw materials and is solidified into cement clinker.
S4, flue gas blending: introducing kiln head residual air into a kiln tail after passing through a kiln head dust collector and a kiln head induced draft fan on a kiln head residual air bypass pipeline, wherein the air volume of the kiln head residual air is 1.0-1.5 Nm3The temperature is controlled to be 100-150 ℃, the mixed gas is mixed with the flue gas discharged from the second dust collector, the temperature and the humidity of the flue gas entering the low-temperature SCR are adjusted, the temperature of the mixed flue gas is increased to 80-150 ℃, and the humidity is reduced to 4-10% so as to achieve the optimal conditions required by the next denitration reaction;
s5, low-temperature SCR denitration: the mixed flue gas is sent into a low-temperature SCR denitration reactor for denitration by a relay fan, so that the emission of the NOx in the flue gas is 50mg/Nm3Then, the mixture is sent to a kiln tail chimney by an exhaust fan and is exhausted to the atmosphere.
Preferably, the kiln tail waste gas in the step S2 enters a corresponding waste heat boiler before entering a kiln tail high-temperature fan, and the kiln head waste air in the step S4 enters a kiln head dust collector.
Preferably, in step S2, the grinding system has a flue gas volume of about 1.7-2.7Nm when grinding3The temperature is 90-130 ℃ per kg-cl; about 1.3-1.8Nm of flue gas air volume during grinding stop3The temperature is 110-.
Preferably, in step S2, the dust collected by the dust collector enters the raw material warehouse.
Preferably, in step S2, the desulfurizing agent for desulfurizing in the semi-dry desulfurizing tower is one or a combination of a plurality of purchased lime, slaked lime or self-made desulfurizing agent; the self-made desulfurizer is prepared by adopting a self-made desulfurizer device to extract hot raw materials from an air duct at the outlet of the decomposing furnace, cooling the raw materials to be within 150 ℃ and then digesting the raw materials, and controlling the water content of the digested materials to be within 2.0%.
Preferably, in step S5, a part of the mixed flue gas before entering the low-temperature SCR denitration reactor is circulated to enter the semi-dry desulfurization tower.
The utility model also aims to provide a desulfurization, denitrification and dedusting ultra-low emission system for producing cement by adopting the high-sulfur raw material of the process, which comprises a cement clinker firing system, wherein the cement clinker firing system comprises a kiln tail preheater, a decomposing furnace, a cement kiln and a cooler, and also comprises a kiln tail high-temperature fan, a grinding system, a dust collector I, a semi-dry desulfurization tower, a dust collector II, a low-temperature SCR denitration reactor, a kiln head dust collector and a kiln head draught fan, the outlet of a cyclone cylinder of a first-stage kiln tail preheater of the kiln tail preheater is connected with an inlet of a grinding system through a kiln tail high-temperature fan, the outlet of the grinding system is connected with a first dust collector, the outlet of the first dust collector is connected with the inlet of a semi-dry desulfurization tower, the outlet of the semi-dry desulfurization tower is connected with a second dust collector, the outlet of the second dust collector is connected with the inlet of a low-temperature SCR denitration reactor through a relay fan, and the outlet of the low-temperature SCR denitration reactor is connected with a kiln tail chimney through an exhaust fan; and the air outlet of the cooler is connected with a kiln head dust collector, and the air outlet of the kiln head dust collector is connected with a second air outlet of the dust collector through a kiln head induced draft fan.
Preferably, the outlet of the decomposing furnace is connected with the inlet of the semi-dry desulfurization tower through a self-made desulfurizer device.
Preferably, the self-made desulfurizer device comprises a material taking unit, a cooling unit and a digestion unit which are connected in sequence; the material taking unit comprises a material taking cyclone, high-temperature gate valves are arranged on an inlet pipeline and an outlet air pipe of the material taking cyclone, the inlet pipeline of the material taking cyclone is connected with an outlet air pipe of the decomposing furnace, the outlet air pipe of the material taking cyclone is connected with an outlet air pipe of a last-but-second kiln tail preheater cyclone, and a discharging pipe of the material taking cyclone is connected with the cooling unit; the cooling unit comprises a first-stage cyclone and a second-stage cyclone, a discharging pipe of a material taking cyclone of the material taking unit is connected with an outlet air pipe of the first-stage cyclone, the outlet air pipe of the first-stage cyclone is connected with an inlet of the second-stage cyclone, the discharging pipe of the second-stage cyclone is connected with the inlet of the first-stage cyclone, cooling air is introduced into the inlet of the first-stage cyclone, and an outlet air pipe of the second-stage cyclone is connected with a waste gas treatment system through a fan; the discharge port of the first-stage cyclone is connected with a material collecting bin through a discharge pipe, the discharge port of the material collecting bin is provided with a gate valve and a screw feeder with a meter, and the outlet of the screw feeder with the meter is connected with a digestion unit; the digestion unit is a dry digester, an exhaust port of the digestion unit is connected with a waste gas treatment system through an air pipe of the cooling unit, and a discharge port of the digestion unit is connected with an inlet of the semi-dry desulfurization tower.
Preferably, the outlet of the decomposing furnace is connected with an inlet air pipe of a cyclone cylinder at the top of the kiln tail preheater through a self-desulfurization channel.
Preferably, the decomposing furnace is a gradient combustion self-denitration decomposing furnace, and an SNCR device is arranged at an outlet of the decomposing furnace and/or an outlet of a last-stage cyclone cylinder of the kiln tail preheater.
Preferably, an SP furnace is arranged between a first-stage kiln tail preheater cyclone and a kiln tail high-temperature fan of the kiln tail preheater, an SP furnace bypass pipeline is arranged, an AQC furnace is arranged between a cooler air outlet and a kiln head dust collector, and an AQC furnace bypass pipeline is arranged.
Preferably, a grinding system bypass pipeline is arranged between the inlet and the outlet of the grinding system.
Preferably, a discharge hole of the second dust collector is connected with an inlet of the semi-dry desulfurization tower or the decomposing furnace.
Preferably, the output end of the relay fan is connected with the inlet of the semi-dry desulfurization tower.
The utility model has the advantages of it is following and beneficial effect:
1. the utility model discloses adopt earlier desulfurization denitration technology to high sulphur raw materials production cement, increased semidry desulfurization, low temperature SCR device on the basis that the source was administered, make SOx/NOx control reaction go on under the conditions such as temperature that is most suitable, dustiness, finally realize that the desulfurization discharges to 35mg Nm3Denitration emission to 50mg/Nm3Dust discharge to 5mg/Nm3The high sulfur content is solvedThe desulfurization and denitrification ultra-low emission problem of cement produced by raw materials; the flue gas temperature reaches the operating temperature window of semi-dry desulfurization, the problem of low service life of low-temperature SCR is solved through semi-dry desulfurization, dust removal and temperature adjustment, the temperature and the humidity of the flue gas are adjusted by fully utilizing kiln head residual air, the denitration efficiency of the low-temperature SCR is improved, the using amount of ammonia water used by SNCR is reduced, and the ammonia escape is controlled;
2. the utility model discloses cement kiln preheater has carried out from taking off the nitre, from desulfurization, SNCR, and from taking off the nitre and having reduced the NOx emission that the body produced, including a small amount of aqueous ammonia among the SNCR, can discharge NOx and control at 50-200mg/Nm3And NOx can be stably controlled to be 50mg/Nm by using a small amount of low-temperature SCR catalyst3The method has the advantages that the current situation that excessive ammonia water can achieve denitration ultra-clean emission is avoided, ammonia escape is avoided, the efficiency of ammonia nitrogen reaction is improved for cement plants with sulfur emission problems, and the corrosion problem caused by the reaction of sulfur and ammonia water is solved;
3. the utility model improves the process system of cement kiln production, introduces the residual air at the kiln head into the kiln tail, and avoids the use of external heat sources and the discharge of associated new harmful substances;
4. coarse dust collection is carried out before semi-dry desulfurization, so that the generation of desulfurization ash is reduced, the desulfurization ash after fine dust collection enters a cement kiln tail decomposing furnace and finally enters a rotary kiln along with raw materials to be solidified into cement clinker, and the problem of treatment of the semi-dry desulfurization ash is solved;
5. the desulfurizer for the semi-dry desulfurization tower adopts a self-made desulfurizer, the hot raw material self-made by a cement kiln is firstly cooled, and then the materials are digested and synergized, so that the digestibility of calcium oxide in the materials can reach over 90 percent, and the high-activity dry powder desulfurizer is prepared, thereby partially or completely replacing the purchased desulfurizer, solving the problem of emission of sulfur dioxide in flue gas, saving the cost of the purchased desulfurizer, and reducing the operation cost of a system;
drawings
Fig. 1 is a flow chart of a system provided by an embodiment of the present invention;
FIG. 2 is a flow chart of the self-made desulfurizer device provided by the embodiment of the present invention for cooling and digesting the material taken from the outlet air duct of the decomposing furnace.
In the figure: 1-1, a kiln tail preheater, 1-2, a decomposing furnace, 1-3 and an SNCR device; 2. rotary kiln, 3-self-desulfurization channel; 4. a cooler, 5-1, an AQC furnace, 5-2, an SP furnace, 5-3, an SP furnace bypass pipeline, 5-4, an AQC furnace bypass pipeline, 6-1, a kiln head dust collector, 6-2, a first dust collector, 6-3, a second dust collector, 7, a kiln head residual air bypass pipeline, 8, a grinding system, 8-1, a grinding system bypass pipeline, 9, a semidry desulfurization tower, 10, a low-temperature SCR denitration reactor, 11, a kiln tail chimney, 12, a self-made desulfurizer device, 12-1, a material taking cyclone cylinder, 12-1-1, a high-temperature gate valve, 12-1-2, a high-temperature gate valve, 12-2-1, a first-stage cyclone cylinder, 12-2-2, a second-stage cyclone cylinder, 12-2-3, a fan, 12-2-4, and a waste gas treatment system, 12-2-5 parts of a material collecting bin, 12-2-6 parts of a gate valve, 12-2-7 parts of a screw feeder with a meter, 12-3 parts of a digestion unit, 13-1 parts of a kiln tail high-temperature fan, 13-2 parts of a kiln head induced draft fan, 13-3 parts of a relay fan, 13-4 parts of an exhaust fan.
The dotted arrowed lines indicate the direction of gas flow and the solid arrowed lines indicate the direction of flow.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the following embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
SO in high-sulfur cement raw material3Higher by more than 0.3 percentIf no desulfurization measure is set, the background sulfur emission reaches 1000-2500mg/Nm3Above, in order to realize desulfurization, denitrification and dust removal of the cement kiln, the emission is ultralow, namely SO2Up to 35mg/Nm3NOx reaches 50mg/Nm3Dust amount of 5mg/Nm3Hereinafter, while the ammonia slip satisfies the national requirements, the present invention will be described in detail with reference to fig. 1.
Example 1
Referring to fig. 1 and 2, an embodiment of the present invention provides a desulfurization, denitrification, dedusting and ultra-low emission process for producing cement from a high-sulfur raw material, comprising the following steps:
s1, cement clinker sintering: the high-sulfur raw material is subjected to heat exchange with hot flue gas by a kiln tail preheater 1-1, then is fed into a decomposing furnace 1-2 for decomposition, is calcined by a rotary kiln 2, and then enters a cooler 4 for cooling to obtain cement clinker; the cement clinker sintering simultaneous sintering system carries out self-denitration, SNCR and self-desulfurization of the decomposing furnace, the self-denitration and SNCR of the decomposing furnace control the NOx in the flue gas discharged from the kiln tail preheater within the lowest NOx emission range without ammonia escape, and the NOx can be controlled within 50-200mg/Nm3(@10％O2)，SO2The discharge concentration is 1000-2500mg/Nm3；
The decomposing furnace self-denitrating adopts the process disclosed in the Chinese patent publication No. CN108167860A, the patent name of which is 'a firing system gradient combustion self-denitrating process method' applied by the company to realize the self-denitrating of the decomposing furnace, and the self-denitrating decomposing furnace creates a reducing region and a temperature field suitable for denitration reaction through air distribution, coal distribution and material distribution and can achieve the denitration of more than 30-70%; a small amount of ammonia spraying denitration is carried out at the outlet of the decomposing furnace 1-2 and/or the outlet of the last stage cyclone cylinder of the kiln tail preheater through an SNCR device 1-3, and the maximum amount of ammonia water sprayed by the SNCR takes no ammonia escape as a bottom line; the combination of the SNCR and the self-denitrification enables the NOx emission to be controlled between 50 and 200mg/Nm3(@10％O2) At this time, ammonia water is added, and the escape of ammonia exceeds the national standard requirement. Therefore, the residual NOx emission reduction is carried out by a rear low-temperature SCR (the temperature is required to be 90-150 ℃) for treatment, so that the excessive unreacted ammonia water and sulfur are prevented from reacting to corrode equipment, and further the whole system does not generate ammonia escape.
The self-desulfurization adopts hot raw materials extracted from an outlet air duct of the decomposing furnace 1-2 as a desulfurizing agent, and the desulfurizing agent is sent to an inlet air duct of a cyclone cylinder at the top of a kiln tail preheater through a self-desulfurization channel 3 to generate desulfurization reaction.
SO at outlet of cyclone cylinder of first-stage kiln tail preheater of kiln tail preheater2The concentration is converted into the national standard discharge concentration of 1000-3. If dry desulfurization is adopted, the operation cost is higher than 5-50 yuan/t.cl, the performance requirement on the desulfurizing agent is higher, ultralow emission is not easy to achieve, and subsequent desulfurization measures are required to be set; if wet desulphurization is adopted, the outlet temperature is lower than 100 ℃ and far lower than the SCR requirement, and the humidity is too high to meet the SCR requirement; if the SCR denitration is carried out at low temperature and then the desulfurization is carried out, sulfur can cause the SCR catalyst to be poisoned. Therefore, the subsequent flue gas is desulfurized by adopting a semi-dry method and then subjected to low-temperature SCR denitration, so that the low-temperature SCR reaction window is achieved, and the aims of desulfurization, denitration, dust removal and ultralow emission are finally achieved.
S2, coarse dust removal and semi-dry desulfurization: waste gas generated at the tail of the kiln enters a dust collector I6-2 for coarse dust collection after coming out of a cyclone cylinder of a first-stage kiln tail preheater of the kiln tail preheater through a kiln tail high-temperature fan 13-1 and being used as a drying heat source for utilization, and if the grinding system 8 stops, the waste gas at the tail of the kiln directly enters the dust collector I6-2 through a bypass pipeline 8-1 of the grinding system, and the dust concentration of a gas outlet of the dust collector is controlled to be 2g/Nm3In the following, the invalid materials entering the semi-dry desulfurization tower are reduced, the operation load and the ash discharge amount of the desulfurization tower are reduced, and the effective utilization rate of the desulfurizer in the semi-dry desulfurization tower is improved. Researches find that the dust in the flue gas, namely the kiln dust, influences the proceeding of the desulfurization reaction when the concentration is too high. Then enters a semi-dry desulfurization tower 9 for desulfurization, SO that SO in the flue gas discharged from the semi-dry desulfurization tower2Emission control at 35mg/Nm3The temperature of the flue gas is 65-100 ℃, and the humidity is 10-15%; the first dust collector 6-2 in the embodiment preferably adopts an electric dust collector.
It should be noted that, if the problem of desulfurization in the kiln tail flue gas does not exist, coarse dust removal and semi-dry desulfurization can be bypassed by the designed first dust collector and the bypass pipeline of the semi-dry desulfurization tower, and the kiln tail flue gas is directly subjected to next fine dust collection.
S3, fine dust removal and desulfurization ash treatment: flue gas from the semidry desulfurization tower 9 is subjected to fine dust collection by a second dust collector 6-3, and the dust concentration of a gas outlet of the second dust collector 6-3 is controlled at 5mg/Nm3The following; a part of the desulfurized ash collected by the second dust collector 6-3 circularly enters the semidry desulfurization tower 9 to continuously adsorb SO in the flue gas2The other part is sent into a kiln tail decomposing furnace 1-2 for oxidation, and finally enters the rotary kiln along with raw materials to be solidified into cement clinker. The low dust concentration prolongs the service life of the low-temperature SCR and avoids the failure phenomena such as blockage. The second dust collector 6-3 in the embodiment preferably adopts a cloth bag dust collector. The desulfurized fly ash is put into a kiln tail decomposing furnace for oxidation, so that the problem of stockpiling and disposing of the semidry desulfurized fly ash is solved, and the semidry desulfurized fly ash mainly comprises calcium sulfite, calcium sulfate, calcium carbonate and calcium hydroxide, wherein the main components of the semidry desulfurized fly ash mainly comprise calcium sulfite which accounts for about 50 percent. The semi-dry desulfurized fly ash cannot be directly used as a cement retarder or a mixed material, and the main reason is that CaSO3Unstable chemical property, slow oxidation, and generation of CaSO4Easily combined with CaO in cement and absorbing water to generate ettringite (CaO. Al)2O3·3CaSO4·3H2O), lowering the performance of cement and concrete. The utility model discloses utilize the decomposing furnace on-line treatment semidry process desulfurization ash, the calcium sulfate that produces after decomposing furnace and rotary kiln calcine finally solidifies to cement clinker. Feeding semi-dry desulfurization ash above a tertiary air pipe of a decomposing furnace, wherein the temperature of the decomposing furnace in the area is generally 850-1100 ℃, the high-temperature aerobic environment required by calcium sulfite oxidation is met, the calcium sulfite can be oxidized into calcium sulfate, and the main chemical reaction is as follows: CaSO3+O2→CaSO4. The decomposition temperature of the calcium sulfate is generally over 1200 ℃, the calcium sulfate is stable in the decomposing furnace and cannot be further decomposed, so that the semi-dry desulfurized fly ash can be completely treated in the decomposing furnace.
It should be noted that when the sulfur content in the raw meal exceeds 1% or the clinker strength is greatly affected by sulfur, the collected desulfurized ash can be left in a bypass discharge pipeline to discharge a small amount of desulfurized ash to water, except for being recycled to the semi-dry desulfurization tower and entering the decomposing furnaceMud mixing material to cope with raw material SO3When the content exceeds 1%, the high strength of the clinker is required, and the sulfur cycle is broken, so that the clinker is not influenced.
S4, flue gas blending: the kiln head residual air is led into the kiln tail through a kiln head dust collector 6-1 on a kiln head residual air bypass pipeline 7 and a kiln head induced draft fan 13-2, and the air volume of the kiln head residual air is 1.0-1.5 Nm3The temperature is controlled to be 100 ℃ and 150 ℃, the mixed gas is mixed with the flue gas discharged from the second dust collector 6-3, the temperature and the humidity of the flue gas entering the low-temperature SCR are adjusted, the temperature of the mixed flue gas is increased to 80-150 ℃, the humidity is reduced to 4-10%, the temperature and the humidity of the flue gas are adjusted and controlled through the kiln head residual air, so that the optimal conditions required by the next denitration reaction are achieved, and the SCR catalyst is ensured to operate in the optimal state; flue gas SO before entering low-temperature SCR denitration reactor2Emission control at 35mg/Nm3The dust concentration was controlled to 5mg/Nm3The temperature is controlled to be 80-150 ℃, the humidity is reduced to 4-10%, and the optimal reaction window conditions of temperature, humidity, dust content and sulfur concentration of the low-temperature SCR catalyst are met.
S5, low-temperature SCR denitration: the mixed flue gas is sent into a low-temperature SCR denitration reactor 10 for denitration through a relay fan 13-3, so that the emission of the NOx in the flue gas is 50mg/Nm3Then, the exhaust fan 13-4 sends the exhaust gas into a kiln tail chimney 11 to be exhausted into the atmosphere. And a relay fan 13-3 is arranged before the semi-dry desulfurization tower 9 and the dust collector II 6-3 to overcome the increase of pressure loss caused by the semi-dry desulfurization tower 9 and the dust collector II and enhance the controllability of the system. The service temperature of the low-temperature SCR denitration technology is 100-220 ℃, the temperature of flue gas desulfurized by a semi-dry method is reduced to about 75 ℃, and the temperature requirement of the low-temperature SCR denitration technology cannot be met. In order to increase the temperature of the flue gas, the flue gas from the semi-dry desulfurization system is mixed with the residual air from the kiln head, and the temperature of the mixed flue gas is about 100 ℃. The mixed flue gas and ammonia gas from an ammonia evaporation system are fully mixed and then enter a low-temperature SCR denitration reactor, and nitrogen oxide in the flue gas and the ammonia gas react to generate nitrogen and water under the action of a low-temperature SCR catalyst, so that the aim of reducing the nitrogen oxide is fulfilled. The purified flue gas is driven by an exhaust fan and is discharged through a chimney.
Low temperature SCThe R denitration technology is obtained by optimizing on the basis of the traditional SCR technology, the technical principle is the same as that of the traditional SCR technology, and mainly NH is used under the action of a catalyst3As reducing agent, selectively reacts with NOx in the smoke gas and generates nontoxic and pollution-free N2And H2And O. The reductant may also be a hydrocarbon (e.g., methane, propane, etc.), ammonia, urea, etc. By NH3For the reducing agent example, the reaction formula is as follows:
4NH3+4NO+O2→4N2+6H2O (1-1)
4NH3+2NO2+O2→3N2+6H2O (1-2)
8NH3+6NO2→7N2+12H2O (1-3)
the superior breakthrough of the low-temperature SCR flue gas denitration technology is low-temperature catalysis, which is different from the activation temperature of the traditional vanadium catalyst up to 400 ℃, the catalyst used by the novel catalysis method can have good activity at 120 ℃, and the applicable temperature window is 100-220 ℃.
The utility model adopts the semi-dry desulfurization and low-temperature SCR denitration process aiming at the cement production of high-sulfur raw materials, and adds the semi-dry desulfurization and low-temperature SCR device on the basis of source treatment, so that the desulfurization and denitration reaction is carried out under the conditions of most suitable temperature, dust content and the like, and the residual air of the bypass kiln head reduces the external heating source for increasing the heating smoke; the direct effect is achieved, and the requirement of desulfurization, denitrification, dedusting and ultra-clean emission of a cement plant is met; the indirect effect reduces the problem of acid corrosion; compared with the prior art, the method has the advantages that the residual air at the kiln head is effectively utilized, and the service life of the SCR catalyst is prolonged; the problem of ammonia escape is thoroughly solved, and the problem of smoke plume in wet desulphurization is solved; solves the problem that the desulfurizer for semi-dry desulfurization is subjected to fluctuation of outsourcing cost, and solves the problem of stockpiling and disposal of semi-dry desulfurization ash.
In order to further realize the purpose that the cement produced by the high-sulfur raw material achieves the purposes of desulfurization, denitrification, dedusting and ultra-clean emission and solve the problems of high operation cost, low service life of SCR catalyst and equipment corrosion caused by the reaction of sulfur and ammonia water, the technical scheme is as follows:
preferably, the kiln tail waste gas in the step S2 enters the corresponding waste heat boiler before entering the kiln tail high-temperature fan 13-1, and the kiln head waste air in the step S4 enters the kiln head dust collector 6-1, and part of heat is recycled, so that the air volume entering the waste heat boiler and the temperature of the outlet of the waste heat boiler can be flexibly adjusted according to the raw fuel moisture, the start and stop of a grinding system, the rainy season and semi-dry desulfurization and the temperature required by low-temperature SCR, and the flue gas temperature required by semi-dry desulfurization and low-temperature SCR is further met. In the embodiment, the waste heat boiler arranged at the tail of the kiln is preferably an SP furnace 5-2, and the waste heat boiler arranged at the head of the kiln is preferably an AQC furnace 5-1.
Preferably, in step S2, the grinding system 8 grinds the flue gas into about 1.7-2.7Nm3The temperature is 90-130 ℃ per kg-cl; about 1.3-1.8Nm of flue gas air volume during grinding stop3The temperature is 110-. According to the start and stop of the grinding system, the air quantity and the temperature of the flue gas are controlled, and the flue gas temperature required by semi-dry desulfurization and low-temperature SCR is further met.
Preferably, in step S2, the dust collected by the first dust collector 6-2 enters the raw material warehouse, so that the dust circulation and the load of the semi-dry desulfurization tower and the subsequent dust removal are reduced, and the efficiency of the desulfurization reaction is improved;
preferably, in step S2, the desulfurizing agent for desulfurizing in the semi-dry desulfurizing tower 9 is one or a combination of a plurality of purchased lime, slaked lime or self-made desulfurizing agent; the method adopts outsourcing lime or slaked lime as a semi-dry desulfurizing agent, is suitable for the condition that the price of calcium oxide or calcium hydroxide is low, and has simpler process.
The self-made desulfurizer adopts a self-made desulfurizer device 12 to extract hot raw materials from an air duct at the outlet of the decomposing furnace 1-2, then the raw materials are cooled to be within 150 ℃ and then digested, and the water content of the digested materials is controlled to be within 2.0 percent, so that the desulfurizer is prepared. So as to reduce the running cost of the outsourcing desulfurizer.
The main reaction formula is as follows:
CaO+H2O→Ca(OH)2
Ca(OH)2+SO2→CaSO3·1/2H2O+1/2H2O
preferably, in step S5, in order to stabilize the cross-sectional wind speed of the semi-dry desulfurization tower, a part of the mixed flue gas before entering the low-temperature SCR denitration reactor 10 is circulated into the semi-dry desulfurization tower 9, so as to ensure the flue gas flow rate and the reaction time (generally, 5S or more) of the semi-dry desulfurization tower.
Example 2
Referring to fig. 1 and 2, a desulfurization, denitrification and dedusting ultra-low emission system for producing cement by using a high-sulfur raw material of the process comprises a cement clinker firing system, wherein the cement clinker firing system comprises a kiln tail preheater 1-1, a decomposing furnace 1-2, a cement kiln 2 and a cooler 4, and further comprises a kiln tail high-temperature fan 13-1, a grinding system 8, a first dust collector 6-2, a semi-dry desulfurization tower 9, a second dust collector 6-3, a low-temperature SCR denitration reactor 10, a kiln head dust collector 6-1 and a kiln head draught fan 13-2, an air outlet of a cyclone cylinder of a first-stage kiln tail preheater of the kiln tail preheater is connected with an inlet of the grinding system 8 through the kiln tail high-temperature fan 13-1, an outlet of the grinding system 8 is connected with the first dust collector 6-2, an air outlet of the first dust collector 6-2 is connected with an inlet of the semi-dry desulfurization, an outlet of the semidry desulfurization tower 9 is connected with a second dust collector 6-3, an air outlet of the second dust collector 6-3 is connected with an inlet of a low-temperature SCR denitration reactor 10 through a relay fan 13-3, and an outlet of the low-temperature SCR denitration reactor 10 is connected with a kiln tail chimney 11 through an exhaust fan 13-4; the air outlet of the cooler 4 is connected with a kiln head dust collector 6-1, and the air outlet of the kiln head dust collector 6-1 is connected with the air outlet of a second dust collector 6-3 through a kiln head draught fan 13-2.
The system adopts the steps of firstly desulfurizing and then denitrating aiming at the cement produced by the high-sulfur raw material, and adds the semi-dry desulfurization tower and the low-temperature SCR device, so that the desulfurization and denitration reaction is carried out under the conditions of the most suitable temperature, dust content and the like, and the problem of desulfurization and denitration ultra-clean emission in the cement produced by the high-sulfur raw material is solved; the kiln head residual air is effectively utilized, the additional heating source for heating smoke is reduced, and the service life of the SCR catalyst is prolonged; the consumption of ammonia water is reduced, the problem of ammonia escape is thoroughly solved, and the problem of acid corrosion is reduced; the problem of smoke plume in wet desulphurization is solved; solves the problem of stockpiling and disposing the semi-dry desulfurized fly ash.
The outlet of the decomposing furnace 1-2 is connected with the inlet of a semi-dry desulfurization tower 9 through a self-made desulfurizer device 12, so that semi-dry desulfurization of the self-made desulfurizer is realized.
The self-made desulfurizer device 12 comprises a material taking unit, a cooling unit and a digestion unit which are sequentially connected, the cement kiln self-heating raw material is extracted from an air pipe at the outlet of the decomposing furnace, the high-temperature material is cooled firstly, and then the material is digested and synergized, so that the digestibility of calcium oxide in the material can reach more than 90 percent, the high-activity desulfurizer is prepared, the self-sufficiency of the desulfurizer is realized, the outsourcing desulfurizer is partially or completely replaced, the emission problem of flue gas sulfur dioxide is solved, the cost of the outsourcing desulfurizer is saved, and the resource consumption of lime ore is reduced.
The material taking unit comprises a material taking cyclone barrel 12-1, high-temperature gate valves 12-1-1 and 12-1-2 are arranged on an inlet pipeline and an outlet air pipe of the material taking cyclone barrel 12-1, the inlet pipeline of the material taking cyclone barrel 12-1 is connected with an outlet air pipe of a decomposing furnace 1-2, the outlet air pipe of the material taking cyclone barrel 12-1 is connected with an outlet air pipe of a penultimate kiln tail preheater cyclone barrel, and a discharging pipe of the material taking cyclone barrel 12-1 is connected with a cooling unit. When material is required to be taken, the material quantity entering the material taking cyclone barrel 12-1 is adjusted through the opening degrees of the high-temperature gate valves 12-1-1 and 12-1-2. The material taking amount can be freely controlled according to the requirement, and the operation is simple and convenient. Under the separation action of the material taking cyclone 12-1, air out of the material taking cyclone 12-1 enters an inlet air pipe of a last-but-one-stage kiln tail preheater cyclone, high-temperature air returns to a heat exchange pipeline of the kiln tail preheater, most heat is recycled, the influence on the energy consumption of a system is small, and materials out of the material taking cyclone 12-1 enter a cooling unit.
The cooling unit comprises a first-stage cyclone 12-2-1 and a second-stage cyclone 12-2-2, a blanking pipe of a material taking cyclone 12-1 of the material taking unit is connected with an outlet air pipe of the first-stage cyclone 12-2-1, an outlet air pipe of the first-stage cyclone 12-2-1 is connected with an inlet of the second-stage cyclone 12-2-2, a blanking pipe of the second-stage cyclone 12-2-2 is connected with an inlet of the first-stage cyclone 12-2-1, cooling air is introduced into the inlet of the first-stage cyclone 12-2-1, and an outlet air pipe of the second-stage cyclone 12-2-2 is connected with an exhaust gas treatment system 12-2-4 through a fan 12-2-3. The high-temperature active raw materials taken out from the material taking unit firstly enter an outlet air pipe of the first-stage cyclone 12-2-1 and then enter the second-stage cyclone 12-2-2, most of the active raw materials are collected under the separation action of the second-stage cyclone 12-2-2, and the second-stage cyclone 12-2-2 preferably adopts a cyclone with the separation efficiency of more than 90 percent. The temperature of active raw materials collected from the second-stage cyclone 12-2-2 is 12-30-600 ℃, the active raw materials are mixed with cooling air and enter the first-stage cyclone 12-2-1, the first-stage cyclone preferably adopts a cyclone with the separation efficiency of more than 80%, and the temperature of the active raw materials separated by the first-stage cyclone 12-2-1 is reduced to be below 150 ℃. Under the air induced by the fan 12-2-3, the cooling air firstly passes through the first-stage cyclone 12-2-1 from bottom to top, then passes through the second-stage cyclone 12-2-2, the dust-containing air discharged from the second-stage cyclone 12-2-2 enters the cement kiln flue gas and waste gas treatment system 12-2-4 after passing through the fan 12-2-3, and the waste gas treatment system 12-2-4 adopts an existing waste gas processor, such as a bag-type dust collector. The high-temperature active raw material can be cooled to below 150 ℃ after being subjected to two-stage suspension cooling, the feasibility of a scheme for directly taking the high-temperature active raw material is realized, and the cooling efficiency is high.
The discharge port of the first-stage cyclone 12-2-1 is connected with a material collecting bin 12-2-5 through a discharge pipe, the discharge port of the material collecting bin 12-2-5 is provided with a gate valve 12-2-6 and a screw feeder 12-2-7 with a meter, and the outlet of the screw feeder 12-2-7 with the meter is connected with a digestion unit 12-3. The cooled active raw materials are firstly fed into a material collecting bin 12-2-5 before digestion and synergism, and are fed into a digestion unit 12-3 after being measured by a screw feeder 12-2-7 with a meter, and the storage period of the material collecting bin 12-2-5 is less than 24 hours, so that the raw materials are prevented from being hardened. The feeding speed and the feeding amount are controlled by the spiral feeder with the meter, and the operation is convenient.
The digestion unit 12-3 is a dry digester, an exhaust port of the digestion unit 12-3 is connected with the waste gas treatment system 12-2-4 through an air pipe of the cooling unit, and a discharge port of the digestion unit 12-3 is connected with an inlet of the semi-dry desulfurization tower. By spraying water into the digestion unit 12-3, the calcium oxide in the material reacts with water to generate active calcium hydroxide, and the water content of the material discharged from the digestion unit 12-3 is controlled within 2.0 percent, namely the active desulfurizer is obtained. The independent dry digester is adopted, so that the digestibility of calcium oxide can reach over 90 percent, and the activity of the prepared desulfurizer is higher. An exhaust port of the digestion unit 12-3 can be connected with an outlet air pipe of a first-stage cyclone 12-2-1 of the cooling unit through an exhaust pipeline, and also can be connected with an outlet air pipe of a second-stage cyclone 12-2-2 of the cooling unit, so as to be further connected with a cement kiln flue gas and waste gas treatment system 12-2-4. The dust-containing water vapor out of the digestion unit 12-3 enters the two-stage suspension cooling unit through the exhaust pipeline and finally enters the waste gas treatment system 12-2-4, the dust-containing water vapor is purified through the waste gas treatment system 12-2-4, the atmospheric pollution is avoided, a dust-containing water vapor purification treatment device does not need to be arranged independently, and the investment and the operation cost are saved. And finally, the prepared desulfurizer enters a semi-dry desulfurization tower for desulfurization reaction, so that semi-dry desulfurization of the self-made desulfurizer is realized.
The outlet of the decomposing furnace 1-2 is connected with the inlet air pipe of the cyclone cylinder at the top of the kiln tail preheater through the self-desulfurization channel 3, so that the self-desulfurization of the hot raw materials is realized.
Decomposing furnace 1-2 is gradient burning from denitration decomposing furnace, the utility model discloses a gradient burning is from denitration decomposing furnace adopts the chinese patent publication No. CN108167860A that this company applied, and the patent name is "a system gradient burning is from denitration technology method" disclosed content, and the self denitration decomposing furnace has created reducing zone and suitable denitration reaction's temperature field through dividing wind, branch coal, branch material, can reach the denitration more than 30-70%. The outlet of the decomposing furnace 1-2 and/or the outlet of the last stage cyclone cylinder of the kiln tail preheater are/is provided with an SNCR device 1-3, and a small amount of ammonia spraying denitration can be carried out.
An SP furnace 5-2 and an SP furnace bypass pipeline 5-3 are arranged between a first-stage kiln tail preheater cyclone cylinder of the kiln tail preheater and a kiln tail high-temperature fan 13-1, an AQC furnace 5-1 and an AQC furnace bypass pipeline 5-4 are arranged between an air outlet of the cooler 4 and a kiln head dust collector 6-1. The SP furnace 5-2 and the AQC furnace 5-1 can recycle partial heat, and can flexibly adjust the air volume entering the waste heat boiler and the temperature of the outlet of the waste heat boiler according to the moisture of the raw fuel, the start and stop of a grinding system, the rainy season, the semi-dry desulfurization and the temperature required by the low-temperature SCR, thereby meeting the flue gas temperature required by the semi-dry desulfurization and the low-temperature SCR.
A grinding system bypass pipeline 8-1 is arranged between the inlet and the outlet of the grinding system 8. When the grinding system 8 stops, kiln tail waste gas can directly enter a first dust collector 6-2 through a bypass pipeline 8-1 of the grinding system.
And a discharge hole of the second dust collector 6-3 is connected with an inlet of a semi-dry desulfurization tower 9 or a decomposing furnace 1-2. A part of the desulfurized ash collected by the second dust collector circularly enters the semidry desulfurization tower to continuously adsorb SO in the flue gas2The utilization rate is improved; the other part is sent into a kiln tail decomposing furnace for oxidation, and finally enters a rotary kiln along with raw materials to be solidified into cement clinker, so that the problem of stockpiling and disposing of semi-dry desulfurized ash is solved.
The output end of the relay fan 13-3 is connected with the inlet 9 of the semi-dry desulfurization tower. Part of the mixed flue gas before entering the low-temperature SCR denitration reactor 10 circularly enters the semi-dry desulfurization tower 9 for regulating the flow rate of the flue gas entering the semi-dry desulfurization tower and ensuring the section wind speed and the reaction time in the semi-dry desulfurization tower.
To sum up, the utility model discloses a change system process flow, to the emission problem of high sulphur raw materials production cement, the first semi-dry process desulfurization of novelty is low temperature SCR denitration again, through kiln head surplus wind bypass and circulation, has satisfied windows such as temperature, humidity, the dust that desulfurization, denitration required, has prolonged the life of catalyst, has avoided the corrosion problems of sulphur and ammonia reaction production, has reduced the system emission reduction cost, has reached the utility model purpose of desulfurization denitration dust removal ultra-clean emission.
The above is only the preferred embodiment of the present invention, and the present invention is not limited to any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention, for example, the external heat source such as hot-blast stove is not used to introduce the kiln tail with the kiln head surplus air, the preheater is not self-denitrating and self-desulfurizing, and the desulfurizing agent is purchased outside without taking out the kiln tail, and the present invention is all included in the protection scope of the present invention.
Claims (9)
1. A desulfurization, denitrification and dedusting ultra-low emission system for producing cement by using a high-sulfur raw material comprises a cement clinker firing system, wherein the cement clinker firing system comprises a kiln tail preheater, a decomposing furnace, a cement kiln and a cooler, it is characterized by also comprising a kiln tail high-temperature fan, a grinding system, a first dust collector, a semidry desulfurization tower, a second dust collector, a low-temperature SCR denitration reactor, a kiln head dust collector and a kiln head draught fan, the outlet of a cyclone cylinder of a first-stage kiln tail preheater of the kiln tail preheater is connected with an inlet of a grinding system through a kiln tail high-temperature fan, the outlet of the grinding system is connected with a first dust collector, the outlet of the first dust collector is connected with the inlet of a semi-dry desulfurization tower, the outlet of the semi-dry desulfurization tower is connected with a second dust collector, the outlet of the second dust collector is connected with the inlet of a low-temperature SCR denitration reactor through a relay fan, and the outlet of the low-temperature SCR denitration reactor is connected with a kiln tail chimney through an exhaust fan; and the air outlet of the cooler is connected with a kiln head dust collector, and the air outlet of the kiln head dust collector is connected with a second air outlet of the dust collector through a kiln head induced draft fan.
2. The desulfurization, denitrification and dedusting ultra-low emission system for producing cement from a high sulfur raw material as set forth in claim 1, wherein the outlet of the decomposing furnace is connected with the inlet of the semi-dry desulfurization tower through a self-made desulfurizer device.
3. The desulfurization, denitrification and dedusting ultra-low emission system for producing cement from a high-sulfur raw material as claimed in claim 2, wherein the self-made desulfurizer device comprises a material taking unit, a cooling unit and a digestion unit which are sequentially connected;
the material taking unit comprises a material taking cyclone, high-temperature gate valves are arranged on an inlet pipeline and an outlet air pipe of the material taking cyclone, the inlet pipeline of the material taking cyclone is connected with an outlet air pipe of the decomposing furnace, the outlet air pipe of the material taking cyclone is connected with an outlet air pipe of a last-but-second kiln tail preheater cyclone, and a discharging pipe of the material taking cyclone is connected with the cooling unit;
the cooling unit comprises a first-stage cyclone and a second-stage cyclone, a discharging pipe of a material taking cyclone of the material taking unit is connected with an outlet air pipe of the first-stage cyclone, the outlet air pipe of the first-stage cyclone is connected with an inlet of the second-stage cyclone, the discharging pipe of the second-stage cyclone is connected with the inlet of the first-stage cyclone, cooling air is introduced into the inlet of the first-stage cyclone, and an outlet air pipe of the second-stage cyclone is connected with a waste gas treatment system through a fan; the discharge port of the first-stage cyclone is connected with a material collecting bin through a discharge pipe, the discharge port of the material collecting bin is provided with a gate valve and a screw feeder with a meter, and the outlet of the screw feeder with the meter is connected with a digestion unit;
the digestion unit is a dry digester, an exhaust port of the digestion unit is connected with a waste gas treatment system through an air pipe of the cooling unit, and a discharge port of the digestion unit is connected with an inlet of the semi-dry desulfurization tower.
4. The system of claim 1, wherein the outlet of the decomposing furnace is connected to the inlet duct of the top cyclone of the kiln tail preheater through a self-desulfurization passage.
5. The system of claim 1, wherein the decomposing furnace is a gradient combustion self-denitration decomposing furnace, and the outlet of the decomposing furnace and/or the outlet of the last stage cyclone of the kiln tail preheater are/is provided with SNCR devices.
6. The system of claim 1, wherein an SP furnace and an SP furnace bypass pipeline are arranged between the cyclone cylinder of the first stage kiln tail preheater of the kiln tail preheater and the high temperature fan at the kiln tail, and an AQC furnace bypass pipeline are arranged between the air outlet of the cooler and the dust collector at the kiln head.
7. The system of claim 1, wherein a bypass line of the pulverizing system is disposed between the inlet and the outlet of the pulverizing system.
8. The desulfurization, denitrification and dedusting ultra-low emission system for producing cement from high-sulfur raw materials as claimed in claim 1, wherein a discharge hole of the second dust collector is connected with an inlet of a semi-dry desulfurization tower or a decomposing furnace.
9. The system of claim 7, wherein the output end of the relay fan is connected to the inlet of the semi-dry desulfurization tower.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920857860.5U CN210159444U (en) | 2019-06-06 | 2019-06-06 | Desulfurization, denitrification and dedusting ultra-low discharge system for producing cement by using high-sulfur raw materials |
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| CN201920857860.5U CN210159444U (en) | 2019-06-06 | 2019-06-06 | Desulfurization, denitrification and dedusting ultra-low discharge system for producing cement by using high-sulfur raw materials |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113289480A (en) * | 2021-05-13 | 2021-08-24 | 天津中材工程研究中心有限公司 | Cement kiln predecomposition system for SNCR denitration optimization |
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2019
- 2019-06-06 CN CN201920857860.5U patent/CN210159444U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113289480A (en) * | 2021-05-13 | 2021-08-24 | 天津中材工程研究中心有限公司 | Cement kiln predecomposition system for SNCR denitration optimization |
| CN113289480B (en) * | 2021-05-13 | 2023-06-09 | 天津中材工程研究中心有限公司 | Cement kiln pre-decomposition system for optimizing SNCR denitration |
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