CN210752027U - Desulfurization, denitrification and dedusting ultralow emission system for producing cement by using low-sulfur raw materials - Google Patents

Desulfurization, denitrification and dedusting ultralow emission system for producing cement by using low-sulfur raw materials Download PDF

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CN210752027U
CN210752027U CN201920859858.1U CN201920859858U CN210752027U CN 210752027 U CN210752027 U CN 210752027U CN 201920859858 U CN201920859858 U CN 201920859858U CN 210752027 U CN210752027 U CN 210752027U
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kiln
outlet
kiln tail
cyclone
low
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马娇媚
彭学平
陈昌华
胡芝娟
赵亮
武晓萍
李波
王伟
高为民
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Tianjin Cement Industry Design and Research Institute Co Ltd
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Tianjin Cement Industry Design and Research Institute Co Ltd
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Abstract

The utility model discloses a desulfurization denitration dust removal ultralow discharge system of low sulphur raw materials cement production, this system includes cement clinker firing system, kiln tail high temperature blower, the grinding system, kiln tail dust collector, low temperature SCR denitration reactor, the wet flue gas desulfurization tower, 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, kiln tail dust collector, low temperature SCR denitration reactor, the wet flue gas desulfurization tower, the exhaust fan, kiln tail chimney links to each other in proper order and sets up, the cooler, kiln head dust collector, the kiln head draught fan links to each other in proper order and sets up, kiln head draught fan exit linkage kiln tail dust collector gas outlet. The utility model discloses adopt dry desulfurization + SCR + wet flue gas desulfurization to low sulfur raw materials production cement, realize the ultra-low emission of SOx/NOx control of low sulfur raw materials production cement.

Description

Desulfurization, denitrification and dedusting ultralow emission system for producing cement by using low-sulfur raw materials
Technical Field
The utility model relates to a flue gas treatment technical field especially relates to a SOx/NOx control dust removal ultralow discharge system of low sulfur 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/Nm3Dust emission of 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. Desulfurization measures generally adopt a desulfurizer spraying and injecting method, a semi-dry method or a wet method desulfurization process, the semi-dry method desulfurization process has large one-time investment, more discharged ash, large floor area and larger difficulty in the reconstruction and implementation of the existing production line; the reaction efficiency of the injection method of calcium oxide or calcium hydroxide or ammonia water and other desulfurizing agents is lower by about 20-30 percent, and the desulfurizing proportion is about 50 percent; the reaction efficiency of the wet desulphurization technology is higher than 90 percent, but the defects are that the white elimination problem exists, extra heating and other measures are needed, and in addition, the wet desulphurization technology 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 the NOx emission are more, the factors 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 almost all production lines relate 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. Low-nitrogen burner and low-nitrogen self-denitrating separatorThe furnace decomposition or staged combustion can reach 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.
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, dedusting and ultra-clean emission is needed.
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.
When producing cement from low sulfur raw material, low sulfur means SO in the raw material3When the content of the sulfur is 0.1-0.5%, the smoke emission is easy to exceed the standard during the grinding stop, and at the moment, if the semi-dry desulfurization is set, the one-time investment cost is high, the use frequency is low, the efficiency of equipment is inevitably reduced due to the excessive range borne by the design and the selection, the energy consumption and the power consumption of a system are improved, and negative effects are generated.
In conclusion, based on the problems, the process and the system which can systematically solve the problems of producing cement by using low-sulfur raw materials and achieve desulfurization, denitrification, dedusting and ultra-clean emission of the cement kiln have important practical significance.
Disclosure of Invention
An object of the utility model is to provide a SOx/NOx control dust removal minimum discharge technology of low sulfur raw materials production cement.
The utility model discloses a realize like this, a SOx/NOx control dust removal ultralow emission technology of low sulfur raw materials cement production, include following step:
s1, cement clinker sintering: the low-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 simultaneous sintering system for cement clinker sintering carries out self-denitration, SNCR, self-desulfurization and dry desulfurization of a decomposing furnace, the self-denitration and SNCR of the decomposing furnace control NOx in flue gas discharged from a kiln tail preheater within the lowest NOx emission range without ammonia escape, and the self-desulfurization and dry desulfurization control SO2Controlling the emission range without influencing the low-temperature SCR catalyst;
s2, dust removal: waste gas generated at the tail of the kiln enters a grinding system as a drying heat source after coming out of 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 kiln tail dust collector for coarse dust collection, if the grinding system stops, the kiln tail waste gas directly enters the kiln tail dust collector through a bypass pipeline of the grinding system, and the concentration of dust at the gas outlet of the kiln tail dust collector is controlled at 5mg/Nm3The following;
s3, 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 of a dust collector at the tail of the kiln, 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 low-temperature SCR denitration reaction;
s4, low-temperature SCR denitration: the mixed flue gas is sent into a low-temperature SCR denitration reactor for denitration, so that the emission of NOx in the flue gas is 50mg/Nm3The following;
s5, wet desulphurization: the flue gas discharged from the low-temperature SCR denitration reactor enters a wet desulphurization tower for desulphurization, SO that SO in the flue gas discharged from the wet desulphurization tower is removed2Emission control at 35mg/Nm3Then, the mixture is sent to a kiln tail chimney by an exhaust fan and is exhausted to the atmosphere.
Preferably, in step S1, the desulfurizing agent for dry desulfurization is one or a combination of several of outsourcing lime, slaked lime or self-making desulfurizing agent;
the self-made desulfurizer adopts a self-made desulfurizer device to extract hot raw materials from an air duct at the outlet of the decomposing furnace, then the hot raw materials are firstly cooled to be within 150 ℃ and then digested, and the moisture content of the digested materials is controlled to be within 2.0 percent, so that the desulfurizer is prepared.
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 S3 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 60-130 ℃ per kg & cl; about 1.3-1.8Nm of flue gas air volume during grinding stop3The temperature is 90-200 ℃ per kg/cl.
Preferably, in step S2, the dust collected by the kiln tail dust collector enters the raw material warehouse.
Preferably, in step S5, the wet desulfurization tower oxidizes the slurry during wet desulfurization, and the desulfurized ash discharged after desulfurization enters the cement grinding system to be used as a cement admixture for recycling; and (4) performing smoke whitening treatment on the smoke subjected to wet desulphurization.
Another object of the utility model is to provide an adopt the ultra-low discharge system of desulfurization denitration dust removal of low sulphur raw materials production cement of above-mentioned technology, including cement clinker system of firing, cement clinker system of firing includes kiln tail preheater, dore furnace, cement kiln and cooler, still includes kiln tail high temperature fan, grinding system, kiln tail dust collector, low temperature SCR denitration reactor, wet flue gas desulfurization tower, kiln head dust collector and kiln head draught fan, kiln tail preheater's first order kiln tail preheater whirlwind section of thick bamboo gas outlet links to each other with grinding system entry through kiln tail high temperature fan, and kiln tail dust collector is connected to grinding system exit, and kiln tail dust collector gas outlet links to each other with low temperature SCR denitration reactor entry, and low temperature SCR denitration reactor export links to each other with wet flue gas desulfurization tower entry, and kiln tail chimney is connected through the exhaust fan to wet flue gas desulfurization tower exit; 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 the inlet of the low-temperature SCR denitration reactor through a kiln head draught fan.
Preferably, the outlet of the decomposing furnace is connected with the inlet air pipe of the cyclone cylinder at the top of the kiln tail preheater sequentially through a self-made desulfurizer device and a desulfurizer conveying 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 type 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 air pipe of a cyclone cylinder at the top of the kiln tail preheater through a desulfurizer conveying device.
Preferably, the desulfurizer conveying device comprises a desulfurizer storage bin, a desulfurizer conveying reamer and an elevator which are sequentially connected, the discharge port of the digestion unit is connected with the inlet of the desulfurizer storage bin through a pneumatic conveying pipeline, and the outlet of the elevator is connected with an inlet air pipe of a cyclone cylinder at the top of the kiln tail preheater.
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.
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 bypass pipeline of the grinding system is arranged between the inlet and the outlet of the grinding system.
Preferably, a wet desulphurization tower bypass pipeline is arranged between the inlet and the outlet of the wet desulphurization tower.
Preferably, the air outlet of the kiln head dust collector is connected with the inlet of the exhaust fan through a kiln head induced draft fan.
The utility model has the advantages of it is following and beneficial effect:
1. the utility model discloses adopt dry desulfurization + SCR + wet flue gas desulfurization technology to low sulphur raw materials cement production, adopt dry desulfurization technique earlier promptly, guarantee that low temperature SCR's catalyst joins in marriage at the back to the requirement of temperature and sulphurThe wet desulphurization method meets the requirement of low sulfur emission, thereby not only reducing the comprehensive cost, but also achieving ultra-low emission, and finally realizing the desulphurization emission to 35mg/Nm3Denitration emission to 50mg/Nm3Dust discharge to 5mg/Nm3The method solves the problem of ultralow emission of desulfurization and denitrification in the cement production by low-sulfur raw materials;
2. the utility model discloses cement kiln preheater has carried out from taking off nitre and SNCR, and from taking off the nitre and having reduced the NOx emission that the body produced, and a small amount of aqueous ammonia in the SNCR in addition can discharge NOx and control at 50-200mg/Nm3And NOx can be stably controlled to 50mg/Nm by using a small amount of 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 discloses cement kiln preheater carries out from desulfurization and dry process desulfurization, and through from desulfurization and dry process desulfurization, desulfurization efficiency can reach more than 50%, SO2Can be controlled at 50-200mg/Nm3The calcium-sulfur ratio is controlled to be 3-10; SO may be desulfurized by self-desulfurization and dry desulfurization2Controlling the temperature in a range required by SCR;
4. the utility model improves the process system of cement kiln production, introduces kiln head residual air into kiln tail, avoids using external heat source and new associated harmful substance emission, makes full use of kiln head residual air to adjust the temperature and humidity of flue gas, and finely removes dust for kiln tail flue gas before entering SCR, solves the service life problem of low-temperature SCR, improves the denitration efficiency of low-temperature SCR, reduces the using amount of ammonia water used by SNCR, and controls ammonia escape;
5. the desulfurizer for dry desulfurization 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 more than 90 percent to prepare the high-activity dry powder desulfurizer, thereby partially or completely replacing an outsourcing desulfurizer, solving the emission problem of flue gas sulfur dioxide, saving the cost of the outsourcing desulfurizer, reducing the operation cost of a system, having less one-time investment of dry desulfurization and solving the problem of SCR sulfur poisoning.
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 desulfurizing agent self-making 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;
fig. 3 is a flow chart of a desulfurizing agent conveying device according to an embodiment of the present invention.
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. the system comprises a cooler, 5-1 parts of an AQC furnace, 5-2 parts of an SP furnace, 5-3 parts of an SP furnace bypass pipeline, 5-4 parts of an AQC furnace bypass pipeline, 6-1 parts of a kiln head dust collector, 6-2 parts of a kiln tail dust collector, 7 parts of a kiln head residual air bypass pipeline, 8 parts of a grinding system, 8-1 parts of a grinding system bypass pipeline, 9 parts of a low-temperature SCR denitration reactor, 10 parts of a wet desulfurization tower, 11 parts of a kiln tail chimney, 12 parts of a self-made desulfurizer, 12-1 parts of a material taking cyclone cylinder, 12-1-1 parts of a high-temperature gate valve, 12-1-2 parts of a high-temperature gate valve, 12-2-1 parts of a first-stage cyclone cylinder, 12-2-2 parts of a second-stage cyclone cylinder, 12-2-3 parts of a fan, 12-2-4 parts of a waste gas treatment system, and 12-2, 12-2-6 parts of a material collecting bin, 12-2-7 parts of a gate valve, 12-3 parts of a screw feeder with a meter, 13-1 parts of a dry digester, 13-2 parts of a kiln tail high-temperature fan, 13-3 parts of a kiln head induced draft fan, 14 parts of an exhaust fan, 14 parts of a desulfurizer conveying device, 14-1 parts of a pneumatic conveying pipeline, 14-2 parts of a desulfurizer storage bin, 14-3 parts of a desulfurizer conveying reamer, 14-4 parts of a lifter.
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 cement raw material3When the content is higher than 0.1-0.5%, if no desulfurization measure is provided, the sulfur emission can not reach 35mg/Nm3The following ultra-clean emission requirements, while having a negative impact on the SCR catalyst; controlling NOx to reach 50mg/Nm3In the following cases, ammonia water that has not reacted with NOx is likely to react with SO2And associated SO3Reaction corrosion equipment; to solve the above problems, the present invention will be described in detail with reference to the accompanying drawings.
Example 1
Referring to fig. 1-3, an embodiment of the present invention provides a desulfurization, denitrification and dedusting ultra-low emission process for producing cement from low sulfur raw material, comprising the following steps:
s1, cement clinker sintering: the low-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, self-desulfurization and dry desulfurization of a decomposing furnace, the self-denitration and SNCR of the decomposing furnace control NOx in flue gas discharged from a preheater at the tail of the kiln within the lowest NOx emission range without ammonia escape, and the NOx can be controlled within 50-200mg/Nm3(@10%O2) Self-and dry desulfurization of SO2Controlling SO in an emission range that does not affect a low temperature SCR catalyst2Can be controlled at 50-200mg/Nm3
The decomposing furnace self-denitrating adopts the process disclosed in 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 realizes the self-denitrating by air distribution and coal distributionThe material distribution creates a reduction zone and a temperature field suitable for denitration reaction, and the denitration can reach more than 30-70%; a small amount of ammonia spraying denitration is carried out at the outlet of the decomposing furnace and/or the outlet of the last stage cyclone cylinder of the kiln tail preheater through an SNCR device, and the maximum amount of ammonia water sprayed by the SNCR takes the fact that ammonia escape is not generated as a bottom line; self-denitration combined with SNCR to control NOx emission to 50-200mg/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-denitration and SNCR before SCR reduce the denitration load of SCR, and SO in flue gas is required to be removed in SCR2Can be controlled to avoid sulfur poisoning and synchronously meet SO2Ultra-low emission requirements;
the self-desulfurization adopts the method that hot raw materials are extracted from an outlet air duct of a decomposing furnace 1-2 and are used as a desulfurizing agent and sent to an inlet air duct of a cyclone cylinder at the top of a preheater at the tail of a kiln to carry out desulfurization reaction; the dry desulfurization adopts a self-made desulfurizer device 12 to extract hot raw materials from an outlet air duct of a decomposing furnace 1-2, then the hot raw materials are firstly cooled to be within 150 ℃ and then digested, the moisture of the digested materials is controlled to be within 2.0 percent, a desulfurizer is prepared, and then the desulfurizer is sent to an inlet air duct of a cyclone cylinder at the top of a kiln tail preheater through a desulfurizer conveying device 14 to carry out desulfurization reaction; the operation cost of the purchased desulfurizer is reduced. When the purchased desulfurizer is low in price, the link of self-desulfurization by using hot raw materials or dry desulfurization by using self-made desulfurizer at the tail of the kiln can be eliminated.
SO at outlet of cyclone cylinder of first-stage kiln tail preheater of kiln tail preheater by using low-sulfur raw material2The concentration is converted into national standard discharge concentration of 50-200mg/Nm3Or more, self-desulfurization and dry desulfurization are adopted, SO that the desulfurization efficiency is over 50 percent, and the requirement of SO at the inlet of the low-temperature SCR is met2And (5) concentration requirement. The lower the absolute value of desulfurization discharge on the kiln tail is controlled, the larger the calcium-sulfur ratio is, the more desulfurizer needs to be injected for dry desulfurization, and the higher the running cost is. Thus, dry desulfurization only removes SO2Controlled within the range required by low-temperature SCR, SO2Can be controlled at50-200mg/Nm3
S2, dust removal: waste gas generated at the tail of the kiln enters a grinding system 8 as a drying heat source after coming out of a cyclone cylinder of a first-stage kiln tail preheater of a kiln tail preheater through a kiln tail high-temperature fan 13-1 to be utilized and then enters a kiln tail dust collector 6-2 to carry out coarse dust collection, if the grinding system 8 stops, the kiln tail waste gas directly enters the kiln tail dust collector 6-2 through a grinding system bypass pipeline 8-1, and the concentration of dust at the gas outlet of the kiln tail dust collector 6-2 is controlled at 5mg/Nm3The low dust concentration prolongs the service life of the low-temperature SCR and avoids the failure phenomena such as blockage. The kiln tail dust collector 6-2 in the embodiment preferably adopts a cloth bag dust collector.
S3, flue gas blending: the temperature of the kiln tail waste gas before entering the SCR can be lower than 100 ℃, the humidity is 10-20%, especially when the grinding system 8 is ground, the temperature is lower than the SCR requirement and the humidity is large, in order to adjust the quality of the flue gas, 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 draught fan 13-2, and the air volume of the kiln head residual air is 1.0-1.5 Nm3The method comprises the following steps of/kg & cl, controlling the temperature to be 100-; flue gas SO before entering a low-temperature SCR denitration reactor 92The emission is controlled between 50 and 200mg/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.
S4, low-temperature SCR denitration: the mixed flue gas is sent into a low-temperature SCR denitration reactor 9 for denitration, so that the emission of the NOx in the flue gas is 50mg/Nm3The following;
the self-desulfurization and dry desulfurization of the sintering system control the sulfur content in the flue gas within the acceptable range of SCR, thereby avoiding the problem of sulfur poisoning of the catalyst; the kiln tail dust collector 6-2 controls the dust concentration at the SCR inlet, and the service life of the SCR catalyst is prolonged.
The service temperature of the low-temperature SCR denitration technology is 90-220 ℃, the temperature of the flue gas subjected to dry desulfurization 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 dry desulphurization 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 low-temperature SCR denitration technology is obtained by optimizing on the basis of the traditional SCR technology, has the same technical principle as the traditional SCR technology, and mainly uses NH 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 ℃.
S5, wet desulphurization: the flue gas from the low-temperature SCR denitration reactor 9 enters a wet desulfurization tower 10 for desulfurization, SO that the SO in the flue gas from the wet desulfurization tower 10 is removed2Emission control at 35mg/Nm3Then, the exhaust fan 13-3 sends the exhaust gas into a kiln tail chimney 11 to be exhausted into the atmosphere.
It should be noted here that, in the present invention, when the environmental protection requirement is not strict or the raw material is not sulphur-free, the wet desulphurization can be bypassed by the designed bypass pipeline.
The utility model discloses to low sulphur raw materials cement production adopt earlier dry desulfurization to satisfy low temperature SCR requirement, on the basis of self-denitration, self-desulfurization source head treatment technology, adopted dry desulfurization, SNCR to make the flue gas of kiln tail preheater export reach the window scope that follow-up low temperature SCR device required, make the SOx/NOx control reaction under the most appropriate temperature, dusty, humidity condition, bypass kiln head surplus wind has reduced the external heating source that the heating flue gas increases; flue gas enters a wet desulfurization tower for desulfurization after low-temperature SCR, so that the requirement of desulfurization, denitrification, dedusting and ultra-clean emission of a cement plant is met; the indirect effect reduces the operation cost; compared with the prior art, the kiln head residual air is effectively utilized, and the service life of the SCR catalyst is prolonged; the problems of ammonia escape and sulfur poisoning of the low-temperature SCR catalyst are thoroughly solved; compared with other methods, the lowest desulfurization, denitrification and dedusting ultra-low emission process method for producing cement by using low-sulfur raw materials is provided. The method and the system are also suitable for desulfurization, denitrification and dedusting ultra-low emission modification of the existing cement production line.
In order to further realize the purpose that the cement produced by low-sulfur raw materials 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, in step S1, the desulfurizing agent for dry desulfurization is one or a combination of several of outsourcing lime, slaked lime or self-making desulfurizing agent; the method adopts outsourcing lime or slaked lime as a wet desulfurizing agent, is suitable for the condition that the price of calcium oxide or calcium hydroxide is low, and has simpler flow.
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.
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 S3 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 different working conditions such as raw fuel moisture, start and stop of a grinding system, rainy season and the like and the temperature required by low-temperature SCR, and the temperature and humidity of the flue gas required by low-temperature SCR are 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. The waste heat power generation can be recovered to generate 18-38kWh/t.cl of power generation, and the power generation is related to the moisture and the property of the raw fuel and the stage number of the kiln tail preheater.
Preferably, in step S2, the grinding system 8 grinds the flue gas into about 1.7-2.7Nm3The temperature is 60-130 ℃ per kg & cl; about 1.3-1.8Nm of flue gas air volume during grinding stop3The temperature is 90-200 ℃ per kg/cl. According to the start and stop of the grinding system 8, the air quantity and the temperature of the flue gas are controlled, and the flue gas temperature required by the low-temperature SCR is further met.
Preferably, in step S2, the dust collected by the kiln tail dust collector 6-2 enters the raw material warehouse, so as to reduce the load of subsequent system operation, prolong the service life of the low-temperature SCR, avoid failure phenomena such as blockage, and improve the efficiency of the desulfurization reaction.
Preferably, in step S5, the wet desulfurization tower 10 performs slurry oxidation during wet desulfurization, specifically, an oxidation fan is provided in the existing oxidation mode, and the desulfurized ash discharged after desulfurization enters the cement grinding system as a cement admixture for recycling.
And (3) performing flue gas whitening treatment on the flue gas subjected to wet desulphurization, wherein the specific treatment method adopts the existing direct heating method or the method of firstly condensing and then heating to perform flue gas whitening treatment. Wherein, the direct heating method: the purified flue gas after desulfurization is directly heated by utilizing the heat recovered by the flue gas before desulfurization, and the heating mode can select GGH or MGGH which is customized according to the actual condition of a project; condensation and heating method: firstly, condensing and dehumidifying to reduce the moisture content of the flue gas, then heating the flue gas by a heat exchanger in a small amplitude, and then sending the flue gas into a kiln tail chimney for discharging; the two methods can make an economic and reasonable whitening scheme according to the environment protection requirements of the places of the projects and the tailoring. The water content and the flue gas temperature in the flue gas after wet desulphurization can be reduced, so that the flue gas discharged into the atmosphere has no white smoke plume which can be identified by naked eyes, and the aims of energy conservation and emission reduction are fulfilled.
Example 2
Referring to fig. 1-3, a desulfurization, denitrification and dedusting ultra-low emission system for producing cement by using the low-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, a cooler 4, a kiln tail high-temperature fan 13-1, a grinding system 8, a kiln tail dust collector 6-2, a low-temperature SCR denitration reactor 9, a wet desulfurization tower 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 kiln tail dust collector 6-2, an air outlet of the kiln tail dust collector 6-2 is connected with an inlet of the low-temperature SCR denitration reactor 9, an outlet of the low-temperature SCR reactor 9 is connected with an inlet, the outlet of the wet desulphurization tower 10 is connected with a kiln tail chimney 11 through an exhaust fan 13-3; 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 inlet of the low-temperature SCR denitration reactor 9 through a kiln head draught fan 13-2.
The system adopts dry desulfurization and low-temperature SCR re-wet desulfurization aiming at the cement production by low-sulfur raw materials, and adds a dry desulfurization tower, a low-temperature SCR device and wet desulfurization, so that desulfurization and denitrification reactions are carried out under the conditions of optimal temperature, dust content and the like, and the aim of desulfurization, denitrification, dedusting and ultralow emission in the cement production by low-sulfur raw materials is fulfilled; 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, the problem of acid corrosion is reduced, and the emission reduction cost of the cement kiln is reduced.
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 sequentially through a self-made desulfurizer device 12 and a desulfurizer conveying device 14, so that 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 type 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 air pipe of a cyclone cylinder at the top of the kiln tail preheater through a desulfurizer conveying device 14. 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. The prepared desulfurizer finally enters an inlet air pipe of a cyclone at the top of a kiln tail preheater to carry out desulfurization reaction.
The desulfurizer conveying device 14 comprises a desulfurizer storage bin 14-2, a desulfurizer conveying reamer 14-3 and an elevator 14-4 which are sequentially connected, a discharge port of the digestion unit 12-3 is connected with an inlet of the desulfurizer storage bin 14-2 through a pneumatic conveying pipeline 14-1, and an outlet of the elevator 14-4 is connected with an inlet air pipe of a cyclone cylinder at the top of the kiln tail preheater. Under the power of a fan, air is used as a pneumatic conveying medium to convey a desulfurizer discharged from a digestion unit 12-3 into a desulfurizer storage bin 14-2, then the desulfurizer is conveyed into a lifter 14-4 through a desulfurizer conveying reamer 14-3 arranged at a discharge port of the desulfurizer storage bin 14-2, and finally the desulfurizer is fed into an inlet air pipe of a cyclone cylinder at the top of a kiln tail preheater, and in the air pipe, the desulfurizer reacts with kiln tail flue gas to remove SO in the flue gas2Thereby reducing SO in the tail flue gas of the kiln2And (4) content.
The outlet of the decomposing furnace 12 is connected with an inlet air pipe of a cyclone cylinder at the top of a preheater at the tail of the kiln, so that the self-desulfurization of 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 part of 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, rainy seasons and the temperature required by low-temperature SCR, thereby meeting the smoke temperature required by 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 is stopped, the kiln tail waste gas can directly enter the kiln tail dust collector 6-2 through the grinding system bypass pipeline 8-1.
A wet desulphurization tower bypass pipeline 10-1 is arranged between an inlet and an outlet of the wet desulphurization tower 10, when raw materials for cement production are replaced by sulfur-free raw materials or the emission requirement is not strict, the wet desulphurization tower is bypassed, flue gas is subjected to low-temperature SCR denitration and then directly enters an exhaust fan and a kiln tail chimney, and is discharged into the atmosphere, and the resistance of the system is lower and more electricity is saved at the moment.
The air outlet of the kiln head dust collector 6-1 is connected with the inlet of an exhaust fan 13-3 through a kiln head draught fan 13-2, and when the low-temperature SCR does not need to regulate the temperature, the kiln head residual air does not contain NOx and SO2Harmful components can be exhausted into the atmosphere through the exhaust fan 13-3 and the kiln tail chimney 11, and part of kiln head residual air can also circularly enter the wet desulphurization tower 10, so that the flue gas flow and the reaction time of the wet desulphurization tower are ensured.
To sum up, the utility model discloses a change system process flow, to the emission problem of low sulphur raw materials production cement, the first dry desulfurization of novelty reduces certain sulphur concentration low temperature SCR denitration again, through kiln head surplus wind bypass and circulation, has satisfied the temperature, humidity, dustiness, harmful components etc. window that desulfurization, denitration required, has prolonged the life of catalyst, has avoided the corrosion problem that sulphur and ammonia reaction produced, has reduced the system emission reduction cost, has reached the utility model purpose of SOx/NOx control 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 (10)

1. A desulfurization, denitrification and dedusting ultra-low emission system for producing cement by using a low-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, and is characterized by further comprising a kiln tail high-temperature fan, a grinding system, a kiln tail dust collector, a low-temperature SCR denitration reactor, a wet desulfurization tower, a kiln head dust collector and a kiln head draught 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 the inlet of the low-temperature SCR denitration reactor through a kiln head draught fan.
2. The desulfurization, denitrification and dedusting ultra-low emission system for producing cement from low sulfur raw material as claimed in claim 1, wherein the outlet of the decomposing furnace is connected with the inlet air pipe of the top cyclone of the kiln tail preheater sequentially through a self-made desulfurizer device and a desulfurizer conveying device.
3. The desulfurization, denitrification and dedusting ultra-low emission system for producing cement from low 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 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 type 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 air pipe of a cyclone cylinder at the top of the kiln tail preheater through a desulfurizer conveying device.
4. The system of claim 3, wherein the desulfurizer conveying device comprises a desulfurizer storage bin, a desulfurizer conveying reamer and a lifter, which are connected in sequence, the discharge port of the digestion unit is connected with the inlet of the desulfurizer storage bin through a pneumatic conveying pipeline, and the outlet of the lifter is connected with the inlet air pipe of the top cyclone cylinder of the kiln tail preheater.
5. The system of claim 1, wherein the outlet of the decomposing furnace is connected to an inlet duct of a top cyclone of a kiln tail preheater.
6. The system of claim 1, wherein 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 a kiln tail preheater.
7. 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.
8. The desulfurization, denitrification and dedusting ultra-low emission system for producing cement from low sulfur raw material as set forth in claim 1, wherein a grinding system bypass pipeline is arranged between the inlet and the outlet of the grinding system.
9. The system of claim 1, wherein a bypass line of the wet desulfurization tower is disposed between the inlet and the outlet of the wet desulfurization tower.
10. The system of claim 1, wherein the outlet of the dust collector at the kiln head is connected to the inlet of the exhaust fan through a draught fan at the kiln head.
CN201920859858.1U 2019-06-06 2019-06-06 Desulfurization, denitrification and dedusting ultralow emission system for producing cement by using low-sulfur raw materials Withdrawn - After Issue CN210752027U (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113694704A (en) * 2021-09-03 2021-11-26 浙江省生态环境科学设计研究院 Self-denitration and SNCR denitration system and method for cement kiln flue gas decomposition furnace
CN114904381A (en) * 2022-05-10 2022-08-16 北京大学 Cement production system and gas treatment method thereof
CN115121109A (en) * 2022-07-20 2022-09-30 天津水泥工业设计研究院有限公司 Low NO X System and process for denitration of flue gas and auxiliary desulfurization treatment of escaping ammonia

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113694704A (en) * 2021-09-03 2021-11-26 浙江省生态环境科学设计研究院 Self-denitration and SNCR denitration system and method for cement kiln flue gas decomposition furnace
CN114904381A (en) * 2022-05-10 2022-08-16 北京大学 Cement production system and gas treatment method thereof
CN114904381B (en) * 2022-05-10 2023-05-23 北京大学 Cement production system and gas treatment method thereof
CN115121109A (en) * 2022-07-20 2022-09-30 天津水泥工业设计研究院有限公司 Low NO X System and process for denitration of flue gas and auxiliary desulfurization treatment of escaping ammonia
CN115121109B (en) * 2022-07-20 2024-04-30 天津水泥工业设计研究院有限公司 Low NOXSystem and process for flue gas denitration and auxiliary desulfurization treatment of escaped ammonia

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