Self-circulating dry desulfurization system and method for cement industry

Abstract

Self-circulating dry desulfurization system and method for cement industry. The present invention proposes a self-circulating dry desulfurization system and method, which includes: a material taking unit, which is connected to the unloading pipe of the first-stage cyclone in the kiln tail preheater to obtain hot raw materials; a preparation unit, which is connected to the material taking unit to prepare a desulfurizer using hot raw materials; and a desulfurization unit, which is respectively connected to the preparation unit and the kiln tail preheater to respectively obtain the desulfurizer and sulfur-containing gas and complete the desulfurization reaction. The self-circulating dry desulfurization system and method disclosed in the present invention highly integrate the desulfurization process and the main process of cement production, extract raw materials from the flue gas at the end of the cement production kiln to prepare the desulfurizer, and there is no need to purchase the desulfurizer. It is flexible in operation and short in construction period. It does not affect the normal production of the production line. It can stably and flexibly achieve the SO2 emission concentration requirements at a lower operating cost, and has good economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of gas desulfurization, and more specifically, to a self-circulating dry desulfurization system and method for cement industry. Background Art

[0002] By the end of 2016, there were more than 1,770 new dry process cement production lines in China (excluding some that were dismantled in 2016). Cement plants use high-temperature calcination to decompose organic sulfides, simple sulfides or sulfates in cement production raw materials and fuels, and emit them into the atmosphere in the form of sulfur oxides (SO2), which seriously affects human health. In recent years, as the country has paid more attention to environmental protection, SO2 emissions have gradually decreased, but the total amount is still large. According to GB4915-2013 "Emission Standards for Air Pollutants from the Cement Industry", the SO2 emission concentration in the exhaust pipe of cement kilns and kiln-mill integrated machines is controlled to be less than 200 mg / m 3 , key areas are controlled at less than 100mg / Nm 3 Therefore, how to economically and effectively strengthen the removal of SO2 in flue gas is an important task for enterprise pollution control. Although there are hundreds of flue gas desulfurization technologies, the most common flue gas desulfurization technologies for cement kilns are wet desulfurization technology, dry desulfurization technology and composite desulfurization technology. Among them, wet desulfurization is the most widely used and efficient desulfurization process. However, there are still a series of problems with wet desulfurization, such as complex system, large footprint, serious equipment corrosion, and a large amount of waste liquid that is difficult to handle. The dry desulfurization process has the characteristics of small footprint, low construction cost, and no pollution, and can obtain a higher desulfurization rate under moderate calcium-sulfur ratio, but its operating cost is high, and the desulfurization product will undergo secondary decomposition. The composite desulfurization technology, which is currently widely recognized in the cement industry, overcomes the disadvantages of the first two methods and achieves low-cost, high-efficiency and rapid desulfurization. However, regardless of whether wet desulfurization, dry desulfurization or composite desulfurization is used, it is necessary to purchase desulfurizers from outside, add different workshops required for the desulfurization system, and equip corresponding personnel, resulting in an increase in investment and production and operation costs. The materials after desulfurization cannot be recycled and reused, and there is still discharge of waste materials.

[0003] With the continuous development of technology, the latest new dry-process cement kiln tail flue gas desulfurization system in recent years has begun to try to adopt a method without purchasing desulfurizers. This method is to add a cyclone dust collector at the outlet of the decomposition furnace, use the negative pressure of the high-temperature fan of the kiln tail system to extract the dust-containing gas containing CaO, and collect the material containing CaO through the cyclone dust collector as the raw material of the desulfurizer. This method overcomes the defects of traditional wet desulfurization, dry desulfurization and composite desulfurization that require the purchase of desulfurizers, but the extraction of ~850℃ hot air at the outlet of the decomposition furnace directly affects the stability of the thermal balance of the kiln tail process system and increases the heat loss of the system. Moreover, the high-temperature fan of the kiln tail system cannot control the extracted air volume, and it is impossible to control the amount of material extracted from the desulfurizer raw material according to the SO2 content of the flue gas and the local SO2 emission requirements. Therefore, its efficiency is not high and unstable, and its desulfurization effect is only about 50%. In order not to affect the original production too much, the extracted hot air volume must meet the SO2 emission concentration in key areas controlled at less than 100mg / Nm 3 It is difficult to achieve, and it also increases the load and power consumption of the high-temperature fan in the kiln tail system. Summary of the invention

[0004] In order to solve the above technical problems, one aspect of the present invention provides a self-circulating dry desulfurization system for cement industry, the self-circulating dry desulfurization system comprising:

[0005] A material taking unit, which is connected to the material discharge pipe of the primary cyclone in the kiln tail preheater to obtain hot raw materials;

[0006] A preparation unit, the preparation unit is connected to the material taking unit to prepare a desulfurizing agent using hot raw materials;

[0007] A desulfurization unit, which is connected to the preparation unit and the kiln tail preheater respectively to obtain the desulfurization agent and the sulfur-containing gas respectively and complete the desulfurization reaction; and

[0008] The material circulation unit is connected to the desulfurization unit and the cement preparation system respectively, so that the product after flue gas desulfurization can be used in the cement grinding system.

[0009] In one embodiment, the first-stage cyclone is the last-stage cyclone in the kiln tail preheater.

[0010] In one embodiment, the material taking unit comprises:

[0011] A material taking pipeline, one end of which is connected to the material discharge pipeline to obtain hot raw materials from the material discharge pipeline, and a retaining valve is provided on the material taking pipeline;

[0012] A first conveying device, the first conveying device is connected to the other end of the material taking pipeline;

[0013] A first dust collector, wherein an air inlet pipe of the first dust collector is connected to a first conveying device to obtain raw materials, and the first dust collector has a first dust collector fan; and

[0014] A second conveying device, one end of which is connected to the first dust collector, and the other end of which is connected to the preparation unit,

[0015] Preferably, the kiln tail preheater is a five-stage preheater, and the first-stage cyclone is a fifth-stage cyclone.

[0016] Preferably, the material taking unit further comprises an air cannon, which is arranged on the material taking pipeline and is closer to the material discharge pipeline than the interception valve.

[0017] Preferably, the material taking unit further comprises an air purification device, which is on an air pipe connecting the first conveying device and the first dust collector.

[0018] Preferably, the intercepting valve is a gate valve.

[0019] Preferably, the first conveying device is a speed-adjustable high-temperature screw conveyor.

[0020] Preferably, the first dust collector is a high temperature ceramic filter bag dust collector.

[0021] Preferably, the second conveying device is a metering screw conveyor, and a speed-regulating rotary air-locking valve is provided at the inlet of the second conveying device.

[0022] In one embodiment, the preparation unit comprises:

[0023] A digester connected to the material taking unit to take hot raw meal and prepare a desulfurizing agent; and

[0024] A third conveying device, one end of which is connected to the digester and the other end of which is connected to the desulfurization unit, so as to convey the desulfurizer to the desulfurization unit.

[0025] Preferably, the third conveying device is a screw pump.

[0026] Preferably, the preparation unit further comprises a metering bin, the inlet end of which is connected to the material taking unit, the outlet end of which is connected to the digester, and the metering bin comprises a load sensor and a speed regulating rotary air lock valve connected to the load sensor and arranged at the outlet end of the metering bin, and the metering bin is used to control the weight of the hot raw material entering the digester.

[0027] Preferably, the preparation unit further comprises a fourth conveying device, one end of which is connected to the digester, and the other end is connected to the feed pipe of the kiln tail preheater. More preferably, a three-way valve is arranged on the feed pipe for connecting the fourth conveying device and the digester, the inlet end of the three-way valve is connected to the digester, and the two outlet ends are respectively connected to the third conveying device and the fourth conveying device.

[0028] Preferably, the preparation unit further comprises a water spraying device, which is connected to the digester to spray water into the digester.

[0029] In one embodiment, the desulfurization unit comprises:

[0030] A desulfurization reactor connected to the preparation unit to obtain a desulfurization agent; and

[0031] The first cyclone dust collector group includes a plurality of cyclone dust collectors, the air inlet end of each of the plurality of cyclone dust collectors is connected to a corresponding one of the first-stage cyclone tubes in the kiln tail preheater, and the air outlet ends are connected to the desulfurization reactor to send the sulfur-containing gas in the kiln tail preheater into the desulfurization reactor, and the discharge end of each of the plurality of cyclone dust collectors is connected to the feed pipe of the kiln tail preheater,

[0032] Preferably, the first cyclone dust collector group includes four cyclone dust collectors.

[0033] In one embodiment, the material circulation unit comprises:

[0034] a second cyclone dust collector group, wherein an air inlet end of the second cyclone dust collector group is connected to the desulfurization unit to receive the flue gas discharged from the desulfurization unit; and

[0035] A zipper machine, one end of which is connected to the discharge end of the second cyclone dust collector group, and the other end of which is connected to the exhaust gas treatment system or the cement grinding system.

[0036] Preferably, the second cyclone dust collector group includes two cyclone dust collectors, and the air inlet end of each of the two cyclone dust collectors is connected to the desulfurization unit, the air outlet end is connected to the raw material grinding system, and the discharge end is connected to the zipper machine.

[0037] Another aspect of the present invention provides a self-circulating dry desulfurization method using the above-mentioned cement industry self-circulating dry desulfurization system, and the self-circulating dry desulfurization method comprises:

[0038] Step A: obtaining hot raw material from the discharge pipe of the primary cyclone in the kiln tail preheater through the material taking unit and transferring the hot raw material to the preparation unit;

[0039] Step B: preparing a desulfurizing agent using hot raw meal through a preparation unit and transferring the desulfurizing agent to a desulfurizing unit;

[0040] Step C: the desulfurization unit obtains the desulfurizing agent from the preparation unit and obtains the sulfur-containing gas from the kiln tail preheater to desulfurize the sulfur-containing gas; and

[0041] Step D: The material circulation unit receives the desulfurized gas from the desulfurization unit to transfer the desulfurization by-product to the cement grinding system.

[0042] In one embodiment, the material taking unit includes a material taking pipeline, a first conveying device, a first dust collector and a second conveying device, wherein step A includes:

[0043] Step A1: Open the interception valve on the material taking pipeline to allow the raw material to enter the first conveying device from the material discharge pipeline;

[0044] Step A2: the first conveying device conveys the hot raw material to the first dust collector to reduce the temperature of the hot raw material; and

[0045] Step A3: The cooled raw material is transported to the preparation unit by the second transport device.

[0046] Preferably, the material taking unit further comprises a first dust collector fan connected to the first dust collector, and step A2 further comprises starting the first dust collector fan to introduce ambient gas into the first dust collector, so that the hot raw meal and the ambient gas are mixed in the air inlet pipe of the first dust collector and the first dust collector to reduce the temperature of the raw meal.

[0047] Preferably, the kiln tail preheater is a five-stage preheater, and the first-stage cyclone is a fifth-stage cyclone.

[0048] Preferably, the material taking unit further comprises an air cannon arranged on the material taking pipe. When the material taking pipe is blocked, the air cannon is used to clear the blockage.

[0049] Preferably, the material taking unit further comprises an air purification device, which is arranged on an air pipe for connecting the first conveying device and the first dust collector to purify the air entering the first dust collector.

[0050] In one embodiment, the preparation unit includes a digester and a third conveying device, and step B includes:

[0051] Step B1: The digester receives hot raw meal from the material taking unit;

[0052] Step B2: hot raw meal is mixed with water in a digester to generate a desulfurizing agent; and

[0053] Step B3: transporting the desulfurizing agent from the digester to the desulfurization unit through the third transport device,

[0054] Preferably, the preparation unit further comprises a water spraying device connected to the digester. In step B2, water is sprayed into the digester using the water spraying device.

[0055] Preferably, the preparation unit further comprises a metering bin arranged between the material taking unit and the digester. In step B1, the weight of the raw material entering the digester is controlled by using the metering bin.

[0056] Preferably, the preparation unit also includes a fourth conveying device arranged between the digester and the kiln tail preheater, so as to convey the desulfurizer to the kiln tail preheater through the fourth conveying device. More preferably, a three-way valve is provided on the air pipe connecting the fourth conveying device and the digester, and the inlet end of the three-way valve is connected to the digester, and the two outlet ends are respectively connected to the third conveying device and the fourth conveying device.

[0057] In one embodiment, the desulfurization unit includes a desulfurization reactor and a first cyclone dust collector group, and step C includes:

[0058] Step C1: the desulfurization reactor obtains the desulfurization agent from the preparation unit;

[0059] Step C2: the first cyclone dust collector group obtains the sulfur-containing gas from the first-stage cyclone in the kiln tail preheater and collects dust from the sulfur-containing gas; and

[0060] Step C3: The first cyclone dust collector group transmits the collected sulfur-containing gas to the desulfurization reactor to mix the desulfurizing agent with the sulfur-containing gas and perform a desulfurization reaction.

[0061] Preferably, the first cyclone dust collector group includes four cyclone dust collectors.

[0062] In one embodiment, the material circulation unit includes a second cyclone dust collector set and a zipper machine, and step D further includes the following steps:

[0063] Step D1: the second cyclone dust collector group receives the desulfurized gas from the desulfurization unit and performs dust collection; and

[0064] Step D2: The zipper machine receives the dust-collected gas from the second cyclone dust collector group and transmits the dust-collected gas to the exhaust gas treatment system or the grinding system.

[0065] Preferably, the second cyclone dust collector group includes two cyclone dust collectors, and the air inlet end of each of the two cyclone dust collectors is connected to the desulfurization unit, the air outlet end is connected to the raw material grinding system, and the discharge end is connected to the zipper machine.

[0066] Preferably, the zipper machine receives the dust-collected material from the second cyclone dust collector group and transmits it to the exhaust gas treatment system or the cement grinding system.

[0067] The self-circulating dry desulfurization system for cement industry disclosed in the present invention highly integrates the desulfurization process with the main process of cement production, extracts raw materials from the flue gas at the end of cement production kiln to prepare desulfurizer, does not need to purchase desulfurizer from outside, does not need to increase production workshops and production personnel, and has flexible operation, short construction period, and does not affect the normal production of the production line. At a low operating cost, it can stably and flexibly achieve SO2 emission concentration control of less than 200mg / Nm 3 Or less than 100mg / Nm3 requirements; and the reaction by-products after flue gas purification can be directly used in the cement production system, thus having better economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic diagram of a self-circulating dry desulfurization system according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0069] The illustrative, non-limiting embodiments of the present invention are described in detail below with reference to the accompanying drawings to further illustrate the self-circulating dry desulfurization system and method according to the present invention.

[0070] Reference Figure 1 One aspect of the present invention provides a self-circulating dry desulfurization system for cement industry, which includes a material taking unit, a preparation unit, a desulfurization unit and a material circulation unit.

[0071] The material taking unit is connected to the discharge pipe 21 of the first-stage cyclone in the kiln tail preheater 2 to obtain hot raw materials containing calcium oxide (CaO). The present invention sets the material taking point of the material taking unit in the discharge pipe 21 of the first-stage cyclone in the kiln tail preheater 2, so it will not affect the high-temperature fan of the kiln tail system, nor will it increase the necessary heat loss of the system. In one embodiment, the first-stage cyclone is the last-stage cyclone of the kiln tail preheater 2. The content of calcium oxide in the hot raw materials in the discharge pipe 21 of the last-stage cyclone is relatively high (more than 60%), so extracting hot raw materials from the discharge pipe 21 of the last-stage cyclone can obtain the highest desulfurization agent preparation efficiency. The preparation unit is connected to the material taking unit to obtain hot raw materials from the material taking unit and use the hot raw materials to prepare the desulfurization agent, that is, in the preparation unit, calcium oxide is mixed with water to react to produce slaked lime (Ca(OH)2), and slaked lime can be used to complete the desulfurization reaction in the desulfurization unit. The desulfurization unit is connected to the preparation unit to obtain the desulfurizer, and at the same time, the desulfurization unit is connected to the kiln tail preheater 2 to obtain the kiln tail sulfur-containing flue gas. The desulfurizer and the sulfur-containing flue gas are mixed in the desulfurization unit and chemically react to generate calcium sulfate (CaSO4), thereby completing the desulfurization of the sulfur-containing gas.

[0072] It can be known from the above description that the self-circulating dry desulfurization system for cement industry proposed by the present invention can be highly integrated with the main process of cement production, and hot raw materials are extracted from the preheater 2 at the kiln tail of the cement factory and used to make desulfurizers. Therefore, there is no need to purchase desulfurizers in the desulfurization process, and the effect of reducing production costs can be achieved; in addition, the raw materials are extracted from the unloading pipe 21 of the first-level cyclone in the kiln tail preheater 2, which can avoid the problem of directly extracting flue gas from the air outlet of the decomposition furnace 1 and affecting the stability of the thermal balance of the kiln tail process system, thereby increasing the heat loss of the system; the reaction byproducts after flue gas desulfurization can be directly used in the cement production system, which has good economic benefits. Therefore, the self-circulating dry desulfurization system for cement industry disclosed by the present invention truly realizes that there is no need to purchase desulfurizers, increase production workshops and production personnel, and has flexible operation, short construction period, and does not affect the normal production of the production line, ensuring the purpose of stable and flexible control of SO2 emission concentration under the premise of low operating costs.

[0073] In one embodiment, the material taking unit includes a material taking pipeline 31, a first conveying device 33, a first dust collector 34, a first dust collector fan 35 and a second conveying device 36 which are connected in sequence.

[0074] The material taking pipeline 31 is connected to the discharge pipeline 21 of the last stage cyclone in the kiln tail preheater 2. The first conveying device 33 mechanically obtains the hot raw material from the kiln tail, so as to suck the hot raw material into the first dust collector 34 under the negative pressure generated by the first dust collector fan 35. At the same time, a interception valve 32 is arranged on the material taking pipeline 31 to control the process and speed of taking the hot raw material. Since the temperature of the kiln tail discharge pipe is relatively high (above 850°C), the material taking pipeline 31 is made of high temperature resistant material. In one embodiment, the interception valve 32 is a gate valve. The gate valve is a valve in which the gate and the valve seat are always in close contact and sealed, and there is no groove in the valve body, so the medium will not be blocked; since the gate valve has a full-diameter flow characteristic, the hot raw material can be passed quickly and without blockage; at the same time, because the gate valve 32 has good sealing performance, it can avoid the leakage of raw material and cause environmental pollution. In one embodiment, the kiln tail preheater 2 is a five-stage preheater, and the last stage cyclone is the fifth stage cyclone.

[0075] The first conveying device 33 is connected to the other end of the material taking pipeline 31, and is used to convey the raw material to the air inlet pipe of the first dust collector 34. Since the raw material extracted from the material discharge pipeline 21 has a high temperature (above 850°C), in one embodiment of the present invention, the first conveying device 33 is a speed-adjustable high-temperature screw conveyor. It has the functions of using a motor to drive the screw to rotate and push the material to achieve the conveying function of an ordinary screw conveyor, and has the functions of stabilizing flow and regulating speed. It has the advantages of simple structure, small cross-sectional area, good sealing, convenient operation, easy maintenance, and convenient closed transportation.

[0076] The air inlet pipe of the first dust collector 34 is connected to the first conveying device 33 to receive the hot raw material conveyed by the first conveying device 33. The first dust collector 34 has a first dust collector fan 35. During operation, the first dust collector fan 35 can generate a certain negative pressure in the raw material conveying pipeline. Under the action of the negative pressure, the hot raw material in the discharge pipeline 21 of the last stage cyclone in the kiln tail preheater 2 enters the air inlet pipe of the first dust collector 34 from the first conveying device 33. On the other hand, the first dust collector fan 35 allows the first dust collector 34 to inhale the gas at the ambient temperature, and the temperature of the raw material is reduced by mixing the gas at the ambient temperature with the hot raw material, for example, to about 250°C. In this way, the need for preparing the desulfurizer is met, and the subsequent equipment of the first dust collector 34 is protected. Since the temperature of the raw material extracted from the unloading pipe 21 of the preheater is relatively high, in one embodiment of the present invention, the filter material of the first dust collector 34 adopts high temperature resistant ceramic filter material to reduce equipment loss caused by high temperature and ensure the normal operation of the material taking unit.

[0077] One end of the second conveying device 36 is connected to the first dust collector 34, and the other end is connected to the preparation unit, so as to convey the raw material cooled in the first dust collector 34 to the preparation unit for the desulfurization agent preparation process. A speed-regulating rotary air lock valve (not shown in the figure) is also provided at the feed inlet of the second conveying device 36, which is used to lock the air to ensure the stability of the metering and conveying of the second conveying device 36. The second conveying device 36 is a high-temperature screw conveyor with a metering function, or it can be other conveying devices with a metering and conveying material function. In one embodiment, the material taking unit also includes an air purification device 37. The air purification device 37 is arranged on the air pipe for connecting the first conveying device 33 and the first dust collector 34 to ensure that the air at the ambient temperature entering the system under the negative pressure of the first dust collector fan 35 does not contain impurities.

[0078] In one embodiment, the material taking unit further comprises an air cannon 38. The air cannon 38 is arranged on the material taking pipeline 31, and can spray compressed gas at a speed exceeding Mach 1, and the compressed gas rushes into the air pipe, overcomes the static friction of the material, and makes the blocked air pipe flow again.

[0079] The material taking process of the material taking unit disclosed in the present invention is as follows: start the first dust collector fan 35 and the first dust collector 34, open the gate valve 32 to generate negative pressure in the air inlet pipe of the first dust collector 34 of the material taking unit; under the action of the negative pressure, start the first conveying device 33, and mechanically allow the hot raw material in the discharge pipe 21 to enter the material taking pipe 31 and enter the air inlet pipe of the first dust collector 34 through the first conveying device 33; the first dust collector 34 inhales ambient gas through the first dust collector fan 35, and the ambient gas is mixed with the powdered hot raw material in the air inlet pipe of the first dust collector 34 and in the first dust collector 34, thereby reducing the temperature of the hot raw material (for example, to about 250°C); after cooling in the first dust collector 34, the raw material enters the preparation unit through the second conveying device 36. It can be seen from the above description that the material taking unit disclosed in the present invention takes materials from the discharge pipe 21 of the last-stage cyclone in the kiln tail preheater 2, preferably takes materials from the discharge pipe 21 of the last-stage cyclone, extracts raw materials with the highest calcium oxide content, and will not affect the stability of the thermal balance of the kiln tail process system, thereby increasing the problem of heat loss in the system; the temperature of the raw material is reduced by the first dust collector fan 35 and the first dust collector 34 and its air inlet pipe, which can protect the subsequent processing equipment. At the same time, ceramic filter material is used inside the first dust collector 34, so that the first dust collector 34 has high temperature resistance, thereby extending its service life.

[0080] Continue to refer to Figure 1 In one embodiment of the present invention, the preparation unit includes a digester 42 and a third conveying device 43.

[0081] The digester 42 is connected to the second conveying device 36 in the material taking unit to obtain raw materials from the material taking unit. The digester 42 has the functions of mixing, digesting, conveying, and dust collection, and can evenly mix the raw materials obtained from the material taking unit with water to form a desulfurizer. In this way, by extracting hot raw materials from the unloading pipe 21 of the kiln tail preheater and using the digester 42 to prepare the desulfurizer, there is no need to purchase the desulfurizer in the desulfurization process, which can achieve the purpose of reducing production costs, and the on-site preparation scheme also has the advantages of short production cycle and flexibility. One end of the third conveying device 43 is connected to the digester 42 and the other end is connected to the desulfurization unit to transport the desulfurizer to the desulfurization unit. In one embodiment, the third conveying device 43 is a screw conveying pump. However, it should be understood by those skilled in the art that the third conveying device 43 can be any conveying device with a gaseous material conveying function commonly used in the field.

[0082] In one embodiment, the preparation unit further includes a metering bin 41. The inlet end of the metering bin 41 is connected to the second conveying device 36 in the material taking unit, and the outlet end is connected to the digester 42, and the metering bin 41 includes a load sensor (not shown in the figure) and a speed regulating rotary air lock valve (not shown in the figure) at the outlet end of the metering bin 41. The load sensor can detect the weight of the raw material in the metering bin 41, and the speed regulating rotary air lock valve can control the discharge amount of the metering bin 41, thereby controlling the total amount of raw material entering the digester 42, so as to ensure the appropriate amount of raw material to meet the production requirements of the desulfurizer, and can coordinate with the overall production rhythm to control the stability of the preparation speed of the desulfurizer. In this way, by setting the metering bin 41 upstream of the digester 42, the quality of the prepared desulfurizer can be guaranteed and the preparation efficiency of the desulfurizer can be improved.

[0083] In one embodiment, the preparation unit further includes a fourth conveying device 44. One end of the fourth conveying device 44 is connected to the digester 42, and the other end is connected to the feeding device (not shown) of the kiln tail preheater 2, so that the prepared desulfurizer is directly transported to the kiln tail preheater 2 to react with the sulfur-containing gas in the kiln tail preheater 2, that is, to have a violent disturbance contact with the flue gas to complete a more in-depth desulfurization reaction, which is the dry desulfurization technology in the traditional process. In this way, the two desulfurization methods are used at the same time to ensure desulfurization of more than 85% and control the SO2 emission concentration in key areas to 100mg / Nm 3 The following environmental protection requirements are met. Preferably, a three-way valve 46 is provided on the air pipe for connecting the fourth conveying device 44 and the digester 42, the inlet end of the three-way valve 46 is connected to the digester 42, and the two outlet ends are respectively connected to the third conveying device 43 and the fourth conveying device 44, so as to adjust the amount of the desulfurizer entering the third conveying device 43 and the fourth conveying device 44 according to the specific emission concentration, so as to achieve the predetermined desulfurization effect.

[0084] In one embodiment, the preparation unit further comprises a water spraying device 45. The water spraying device 45 is connected to the digester 42, and the sprayed water fully reacts with the raw material in the digester 42 to generate a desulfurizing agent.

[0085] Continue to refer to Figure 1 The desulfurization unit includes a desulfurization reactor 51 and a first cyclone dust collector group 52.

[0086] The desulfurization reactor 51 is connected to the third conveying device 43 in the preparation unit to obtain the desulfurization agent. The first cyclone dust collector group 52 includes a plurality of cyclone dust collectors, each of which has an air inlet end connected to a corresponding one of the first-stage cyclones in the kiln tail preheater 2, and an air outlet end connected to the desulfurization reactor 51, so as to deliver the sulfur-containing gas in the kiln tail preheater 2 to the desulfurization reactor 51. In this way, by adding the first cyclone dust collector group 52 to the outlet end of the first-stage cyclone of the original preheater system, the dust concentration of the sulfur-containing high-temperature gas leaving the first-stage cyclone can be reduced to about 15g / Nm 3 , to realize the re-collection of raw material powder, thereby greatly reducing the consumption of desulfurizer, increasing the purity of desulfurization by-products and reducing the total amount of desulfurization by-products. The purified sulfur-containing flue gas enters the desulfurization reactor 51. The desulfurization reactor 51 is an efficient low-resistance reactor with a special structure for optimizing fluid distribution. The sulfur-containing flue gas can fully react with the desulfurizer for more than 5 seconds in the desulfurization reactor 51 to generate calcium sulfate (CaSO2). The efficient desulfurization reaction process that reduces the gas flow rate and increases the reaction rate of the desulfurizer and the gas can effectively remove SO2 and ensure that the SO2 concentration in the exhaust gas meets the national environmental protection standards. In one embodiment, the first cyclone dust collector group 52 includes four cyclone dust collectors, each of the four cyclone dust collectors corresponds to a corresponding one of the first-stage cyclones in the kiln tail preheater 2, so as to collect dust from the high-temperature sulfur-containing gas and reduce the dust concentration of the sulfur-containing gas sent to the desulfurization reactor 51.

[0087] Reference Figure 1 The material circulation unit in the self-circulating dry desulfurization system proposed in the present invention includes a second cyclone dust collector group 61 and a zipper machine 62.

[0088] The air inlet end of the second cyclone dust collector group 61 is connected to the subsequent air duct of the desulfurization reactor 51 in the desulfurization unit to receive the flue gas after desulfurization, and its air outlet end is connected to the raw material grinding system 8. One end of the zipper machine 62 is connected to the discharge end of the second cyclone dust collector group 61, and the other end is connected to the conveying equipment of the exhaust gas treatment system 7 to send the gas after the dust collection by the second cyclone dust collector group 61 into the raw material grinding system 8, and the collected desulfurization by-products are sent to the conveying equipment of the exhaust gas treatment system 7 by the zipper machine 62. The flue gas discharged from the desulfurization reactor 51 passes through the dust collection of the second cyclone dust collector group 61, which can ensure that the gas entering the raw material grinding system 8 contains almost no calcium sulfate and slaked lime. In addition, the materials collected by the second cyclone dust collector group 61 can be sent to a separate storage tank by the zipper machine 62 and the conveying equipment of the exhaust gas treatment system 7, and added to the cement grinding system (not shown in the figure) as a coagulant according to the needs of the cement grinding process, thereby forming a self-circulating desulfurization system for recycling materials in the cement plant, generating no waste, and meeting national environmental protection requirements; at the same time, the materials can also be sent to the kiln elevator by the zipper machine 62 and the conveying equipment of the exhaust gas treatment system 7, and enter the kiln tail preheater system 2, to react with the flue gas using conventional dry technology to reduce the SO2 content in the exhaust flue gas, thereby ensuring the best desulfurization effect.

[0089] In one embodiment, the second cyclone dust collector group 61 includes two cyclone dust collectors, and the air inlet end of each of the two cyclone dust collectors is connected to the subsequent air duct of the desulfurization reactor 51 in the desulfurization unit, and the discharge end is connected to the zipper machine 62. However, it should be understood by those skilled in the art that the number of the second cyclone dust collector group 61 is not limited to two, and can be adjusted according to specific working conditions.

[0090] From the above description, it can be known that the self-circulating dry desulfurization system proposed in the present invention can be highly integrated with the main process of cement production. There is no need to purchase desulfurizers in the desulfurization process, thereby achieving the effect of reducing production costs; in addition, extracting raw materials from the discharge pipe 21 of the last-stage cyclone in the kiln tail preheater 2 can avoid directly extracting flue gas from the air outlet of the decomposition furnace 1, which affects the stability of the thermal balance of the kiln tail process system and thereby increases the heat loss of the system; adding a first cyclone dust collector group 52 to the first-stage cyclone of the kiln tail preheater 2 can reduce the dust concentration of the flue gas entering the desulfurization reactor 51, thereby reducing the amount of desulfurizer used; adding a second cyclone dust collector group 61 to the material circulation unit can ensure that the gas entering the raw material grinding system 8 contains almost no calcium sulfate and slaked lime. The self-circulating dry desulfurization system disclosed in the present invention truly realizes that there is no need to purchase desulfurization agents from outside and increase production workshops and production personnel without affecting normal production. It is flexible in operation and has a short construction period. It does not affect the normal production of the production line and can stably and flexibly control the emission concentration of SO2 while ensuring low operating costs.

[0091] Another aspect of the present invention provides a self-circulating dry desulfurization method using the above-mentioned self-circulating dry desulfurization system. The self-circulating dry desulfurization method is described in detail below with reference to the accompanying drawings.

[0092] Step A: The hot raw material is obtained from the discharge pipe 21 of the last stage cyclone in the kiln tail preheater 2 through the material taking unit and is transmitted to the preparation unit. The material taking point of the material taking unit in the present invention is at the discharge pipe 21 of the last stage cyclone in the kiln tail preheater 2, so it will not affect the high-temperature fan of the kiln tail system, nor will it increase the necessary heat loss of the system. Step B: The raw material is mixed with water in the preparation unit to prepare a desulfurizer, and the desulfurizer is transmitted to the desulfurization unit. Step C: The desulfurization unit obtains the desulfurizer from the preparation unit and obtains the sulfur-containing gas from the kiln tail preheater 2 to mix and react chemically in the desulfurization unit to generate calcium sulfate (CaSO4), thereby completing the desulfurization process. Step D: The material circulation unit receives the desulfurized gas from the desulfurization unit, processes this part of the gas to obtain the desulfurization by-product, and then sends the desulfurization by-product to the cement grinding system, thereby forming a material recycling of the cement plant.

[0093] In one embodiment, step A of obtaining the hot raw material from the discharge pipe 21 of the last stage cyclone by the material taking unit and transferring it to the preparation unit includes the following steps.

[0094] Step A1: Open the gate valve 32 on the material taking pipeline 31 to allow the hot raw material to enter the first conveying device 33 from the discharge pipeline 21 of the last stage cyclone. The gate valve 32 can ensure that the hot raw material passes quickly and without blockage, and has good sealing properties to prevent the raw material from leaking out and causing environmental pollution. In one embodiment, the kiln tail preheater 2 is a five-stage preheater, and because the calcium oxide content in the raw material in the discharge pipeline 21 of the fifth stage cyclone is relatively high (more than 60%), the raw material extracted from the discharge pipeline 21 of the fifth stage cyclone can obtain the highest desulfurization agent preparation efficiency.

[0095] Step A2: The first conveying device 33 conveys the raw material to the air inlet pipe of the first dust collector 34. The first dust collector 34 is connected to the first dust collector fan 35. After the high-temperature raw material is fed into the air inlet pipe of the first dust collector 34, the first dust collector fan 35 is started to introduce ambient gas into the first dust collector 34 and its air inlet pipe, so that the raw material and the ambient gas are mixed in the first dust collector 34 and its air inlet pipe to reduce the temperature of the raw material. In this way, the first dust collector 34 can perform dust collection and cooling operations on the high-temperature raw material to reduce the temperature of the hot raw material and collect the raw material. In one embodiment, the first conveying device 33 is a speed-adjustable high-temperature screw conveyor, which is arranged horizontally and has the advantages of high temperature resistance, simple structure, small cross-sectional area, good sealing, convenient operation, easy maintenance, and convenient closed transportation.

[0096] Step A3: conveying the cooled raw material to the preparation unit through the second conveying device 36. In one embodiment, the second conveying device 36 may also be, but not limited to, a metering screw conveyor.

[0097] Preferably, the material taking unit further comprises a purification device 37 arranged on the air inlet pipe connecting the first conveying device 33 and the first dust collector 34, that is, on the air inlet pipe of the first dust collector, so that the incoming air does not contain impurities that affect the operation of the material taking unit.

[0098] Preferably, the material taking unit further comprises an air cannon 38 arranged on the material taking pipe, and when the material taking pipe is blocked, the blockage is cleared by using the air cannon 38. The air cannon 38 can spray compressed gas at a speed exceeding Mach 1, and the compressed gas rushes into the air pipe, overcomes the static friction of the material, and makes the blocked air pipe flow again.

[0099] In one embodiment of the present invention, the step B of preparing a desulfurizing agent using raw meal by a preparation unit and transferring the desulfurizing agent to a desulfurizing unit includes the following steps.

[0100] Step B1: Transfer the hot raw meal from the material taking unit to the digester 42. In this way, by using the hot raw meal obtained from the discharge barrel of the kiln tail preheater and preparing the desulfurizer using the digester 42, there is no need to purchase the desulfurizer in the desulfurization process, which can achieve the effect of reducing production costs, and the on-site preparation scheme also has the advantages of short production cycle and flexibility. Preferably, in the step of transferring the raw meal from the material taking unit to the digester 42, the metering bin 41 is used to control the weight of the raw meal entering the digester 42, thereby controlling the total amount of raw meal entering the digester 42, so as to ensure a suitable amount of raw meal to meet the production requirements of the desulfurizer, and the stability of the preparation speed of the desulfurizer can be controlled in coordination with the overall production rhythm.

[0101] Step B2: The raw meal is mixed with water in the digester 42 to generate a desulfurizing agent. In this way, by extracting hot raw meal from the discharge barrel of the kiln tail preheater and using the digester 42 to prepare the desulfurizing agent, there is no need to purchase the desulfurizing agent from outside in the desulfurization process, which can achieve the purpose of reducing production costs, and the on-site preparation scheme also has the advantages of short production cycle and flexibility. In one embodiment, the preparation unit also includes a water spraying device 45 connected to the digester 42. In step B2, the water spraying device 45 is used to spray water into the digester, and the amount of water sprayed into the digester 42 can be controlled to control the preparation of the desulfurizing agent.

[0102] Step B3: Desulfurizing agent is transported from digester 42 to desulfurization unit through third transport device 43. Third transport device 43 is a screw transport pump. However, it should be understood by those skilled in the art that third transport device 43 can be any transport device commonly used in the art with gaseous material transport function.

[0103] Preferably, the desulfurizer prepared in the digester 42 can also be transported to the kiln tail preheater 2 through the fourth conveying device 44 disposed between the digester 42 and the kiln tail preheater 2, so that the prepared desulfurizer is directly transported to the kiln tail preheater 2 to react with the sulfur-containing gas therein, that is, to make violent disturbance contact with the flue gas to complete a more in-depth desulfurization reaction, which is also the dry desulfurization technology in the traditional process. More preferably, a three-way valve 46 is disposed on the air pipe for connecting the third conveying device 43 and the digester 42 to control the amount of desulfurizer delivered to the third conveying device 43 and the fourth conveying device 44, so that the desulfurization reaction of the two desulfurization methods can be achieved.

[0104] In one embodiment, step C in which the desulfurization unit obtains the desulfurization agent from the preparation unit and obtains the sulfur-containing gas from the kiln tail preheater 2 includes the following steps.

[0105] Step C1: The desulfurization reactor 51 obtains the desulfurization agent from the preparation unit. Step C2: The first cyclone dust collector group 52 obtains the sulfur-containing gas from the first-stage preheater in the kiln tail preheater 2 and collects dust from the sulfur-containing gas to reduce the dust concentration of the sulfur-containing gas. In one embodiment, the first cyclone dust collector group 52 includes, but is not limited to, four cyclone dust collectors. Step C3: The first cyclone dust collector group 52 transmits the dust-collected sulfur-containing gas to the desulfurization reactor 51, so that the desulfurization agent and the sulfur-containing gas are quickly mixed in the desulfurization reactor 51 to perform a desulfurization reaction.

[0106] In one embodiment of the present invention, after the desulfurization unit completes the desulfurization step, the desulfurized gas is applied to the raw material grinding system 8, and the collected desulfurization by-products are sent to the cement grinding system through the conveying equipment of the exhaust gas treatment system 7, or to the kiln tail system 2, that is, the self-circulating dry desulfurization method also includes the following steps.

[0107] Step D1: The second cyclone dust collector group 61 receives the desulfurized gas from the subsequent air duct of the desulfurization reactor 51 in the desulfurization unit and performs dust collection, that is, collects calcium sulfate and slaked lime in the desulfurized gas. Preferably, the second cyclone dust collector group 61 includes, but is not limited to, two cyclone dust collectors. Step D2: The gas after dust collection is sent to the raw material grinding system 8, and the collected material is conveyed to the conveying equipment of the exhaust gas treatment system 7 through the zipper machine 62. In this way, the flue gas discharged from the desulfurization reactor 51 passes through the dust collection of the second cyclone dust collector group 61, which can ensure that the gas entering the raw material grinding system 8 contains almost no calcium sulfate and slaked lime components. The materials collected by the second cyclone dust collector group 61 can be sent to a separate storage tank through the conveying equipment of the exhaust gas treatment system 7, and added to the cement grinding system as a coagulant according to the needs of the cement grinding process, forming a self-circulating desulfurization system that recycles materials, does not generate waste, and meets national environmental protection requirements; at the same time, it can also be sent to the kiln elevator and enter the preheater system to react with the flue gas with the usual dry technology to reduce the SO2 content in the exhaust gas and ensure the best desulfurization effect.

[0108] While the present invention has been described in conjunction with specific exemplary embodiments, it should be understood that the present invention is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent structures included within the spirit and scope of the appended claims and their equivalents.

Claims

1. A self-circulating dry desulfurization system for cement industry, characterized in that: include: A material taking unit, wherein the material taking unit is connected to a material discharge pipe of a primary cyclone in a preheater at the kiln tail to obtain hot raw materials; A preparation unit, the preparation unit is connected to the material taking unit to prepare a desulfurizing agent using hot raw materials; A desulfurization unit, wherein the desulfurization unit is connected to the preparation unit and the kiln tail preheater respectively to obtain a desulfurizing agent and sulfur-containing gas respectively and complete a desulfurization reaction; and A material circulation unit is connected to the desulfurization unit and the cement preparation system respectively, so as to use the product after flue gas desulfurization in the cement grinding system.

2. The self-circulating dry desulfurization system for cement industry according to claim 1 is characterized in that: The first-stage cyclone is the last-stage cyclone in the kiln tail preheater.

3. The self-circulating dry desulfurization system for cement industry according to claim 1 is characterized in that: The material taking unit comprises: A material taking pipeline, one end of which is connected to the material discharge pipeline to obtain hot raw materials from the material discharge pipeline, and a retaining valve is provided on the material taking pipeline; A first conveying device, wherein the first conveying device is connected to the other end of the material taking pipeline; a first dust collector, wherein an air inlet pipe of the first dust collector is connected to the first conveying device to obtain raw materials, and the first dust collector has a first dust collector fan; and A second conveying device, one end of which is connected to the first dust collector, and the other end of which is connected to the preparation unit.

4. The self-circulating dry desulfurization system for cement industry according to claim 3 is characterized in that: The kiln tail preheater is a five-stage preheater, and the first-stage cyclone is a fifth-stage cyclone.

5. The self-circulating dry desulfurization system for cement industry according to claim 3 is characterized in that: The material taking unit further comprises an air cannon, which is arranged on the material taking pipeline and is closer to the material discharge pipeline than the intercepting valve.

6. The self-circulating dry desulfurization system for cement industry according to claim 3 is characterized in that: The material taking unit further comprises an air purification device, and the air purification device is on an air pipe used to connect the first conveying device and the first dust collector.

7. The self-circulating dry desulfurization system for cement industry according to claim 3 is characterized in that: The intercepting valve is a gate valve.

8. The self-circulating dry desulfurization system for cement industry according to claim 3 is characterized in that: The first conveying device is a speed-adjustable high-temperature screw conveyor.

9. The self-circulating dry desulfurization system for cement industry according to claim 3, characterized in that: The first dust collector is a high-temperature ceramic filter bag dust collector.

10. The cement industry self-circulating dry desulfurization system according to claim 3, characterized in that: The second conveying device is a metering screw conveyor, and a speed-regulating rotary air-locking valve is provided at the inlet of the second conveying device.

11. The cement industry self-circulating dry desulfurization system according to claim 1, characterized in that: The preparation unit comprises: A digester connected to the material taking unit to obtain hot raw meal and prepare a desulfurizing agent; and A third conveying device, one end of which is connected to the digester, and the other end of which is connected to the desulfurization unit, so as to convey the desulfurizer to the desulfurization unit.

12. The cement industry self-circulating dry desulfurization system according to claim 11, characterized in that: The third conveying device is a screw pump.

13. The cement industry self-circulating dry desulfurization system according to claim 11, characterized in that: The preparation unit also includes a metering bin, the inlet end of which is connected to the material taking unit, and the outlet end of which is connected to the digester. The metering bin also includes a load sensor and a speed-regulating rotary air-locking valve connected to the load sensor and arranged at the outlet end of the metering bin. The metering bin is used to control the weight of the raw material entering the digester.

14. The cement industry self-circulating dry desulfurization system according to claim 11, characterized in that: The preparation unit further comprises a fourth conveying device, one end of which is connected to the digester, and the other end of which is connected to the feed pipe of the kiln tail preheater.

15. The self-circulating dry desulfurization system for cement industry according to claim 14, characterized in that: A three-way valve is provided on the material pipe for connecting the fourth conveying device and the digester, wherein the inlet end of the three-way valve is connected to the digester, and the two outlet ends are respectively connected to the third conveying device and the fourth conveying device.

16. The cement industry self-circulating dry desulfurization system according to claim 11, characterized in that: The preparation unit further comprises a water spraying device, which is connected to the digester to spray water into the digester.

17. The self-circulating dry desulfurization system for cement industry according to claim 1, characterized in that: The desulfurization unit comprises: a desulfurization reactor connected to the preparation unit to obtain a desulfurization agent; and The first cyclone dust collector group includes a plurality of cyclone dust collectors, wherein the air inlet end of each of the plurality of cyclone dust collectors is connected to a corresponding one of the first-stage cyclones in the kiln tail preheater, and the air outlet ends are connected to the desulfurization reactor to deliver the sulfur-containing gas in the kiln tail preheater into the desulfurization reactor, and the discharge end of each of the plurality of cyclone dust collectors is connected to the feed pipe of the kiln tail preheater.

18. The cement industry self-circulating dry desulfurization system according to claim 17, characterized in that: The first cyclone dust collector group includes four cyclone dust collectors.

19. The cement industry self-circulating dry desulfurization system according to claim 1, characterized in that: The material circulation unit comprises: a second cyclone dust collector group, wherein an air inlet end of the second cyclone dust collector group is connected to the desulfurization unit to receive the flue gas discharged from the desulfurization unit; and A zipper machine, one end of which is connected to the discharge end of the second cyclone dust collector group, and the other end of which is connected to the exhaust gas treatment system or the cement grinding system.

20. The cement industry self-circulating dry desulfurization system according to claim 19, characterized in that: The second cyclone dust collector group includes two cyclone dust collectors, and each of the two cyclone dust collectors has an air inlet end connected to the desulfurization unit, an air outlet end connected to the raw material grinding system, and a discharge end connected to the zipper machine.

21. A self-circulating dry desulfurization method for cement industry using the self-circulating dry desulfurization system according to any one of claims 1 to 20, characterized in that: include: Step A: obtaining hot raw material from the discharge pipe of the primary cyclone in the kiln tail preheater through the material taking unit and transferring the hot raw material to the preparation unit; Step B: preparing a desulfurizing agent using hot raw materials through the preparation unit and transferring the desulfurizing agent to the desulfurization unit; Step C: the desulfurization unit obtains the desulfurizer from the preparation unit and obtains the sulfur-containing gas from the kiln tail preheater to desulfurize the sulfur-containing gas; and Step D: The material circulation unit receives the desulfurized gas from the desulfurization unit to transfer the desulfurization by-product to the cement grinding system.

22. The self-circulating dry desulfurization method for cement industry according to claim 21, characterized in that: The material taking unit comprises a material taking pipeline, a first conveying device, a first dust collector and a second conveying device, wherein the step A comprises: Step A1: opening the interception valve on the material taking pipeline to allow the raw material to enter the first conveying device from the material discharge pipeline; Step A2: the first conveying device conveys the hot raw material to the first dust collector to reduce the temperature of the hot raw material; and Step A3: transporting the cooled raw material to the preparation unit through the second transport device.

23. The self-circulating dry desulfurization method for cement industry according to claim 22, characterized in that: The material taking unit also includes a first dust collector fan connected to the first dust collector. In step A2, the first dust collector fan is also started to introduce ambient gas into the first dust collector, so that the hot raw material is mixed with the ambient gas in the air inlet pipe of the first dust collector and the first dust collector to reduce the temperature of the raw material.

24. The self-circulating dry desulfurization method for cement industry according to claim 22, characterized in that: The kiln tail preheater is a five-stage preheater, and the first-stage cyclone is a fifth-stage cyclone.

25. The self-circulating dry desulfurization method for cement industry according to claim 22, characterized in that: The material taking unit further comprises an air cannon arranged on the material taking pipe. When the material taking pipe is blocked, the air cannon is used to clear the blockage.

26. The self-circulating dry desulfurization method for cement industry according to claim 22, characterized in that: The material taking unit further includes an air purification device, which is disposed on an air pipe connecting the first conveying device and the first dust collector to purify air entering the first dust collector.

27. The self-circulating dry desulfurization method for cement industry according to claim 21, characterized in that: The preparation unit includes a digester and a third conveying device, and the step B includes: Step B1: the digester receives hot raw material from the material taking unit; Step B2: hot raw meal is mixed with water in the digester to generate a desulfurizing agent; and Step B3: transporting the desulfurizing agent from the digester to the desulfurization unit through the third transporting device.

28. The self-circulating dry desulfurization method for cement industry according to claim 27, characterized in that: The preparation unit further comprises a water spraying device connected to the digester. In the step B2, the water spraying device is used to spray water into the digester.

29. The self-circulating dry desulfurization method for cement industry according to claim 27, characterized in that: The preparation unit further comprises a metering bin arranged between the material taking unit and the digester. In the step B1, the metering bin is used to control the weight of the raw material entering the digester.

30. The self-circulating dry desulfurization method for cement industry according to claim 27, characterized in that: The preparation unit also includes a fourth conveying device arranged between the digester and the kiln tail preheater, so as to convey the desulfurizer to the kiln tail preheater through the fourth conveying device, and a three-way valve is arranged on the air pipe connecting the fourth conveying device and the digester, the inlet end of the three-way valve is connected to the digester, and the two outlet ends are respectively connected to the third conveying device and the fourth conveying device.

31. The self-circulating dry desulfurization method for cement industry according to claim 21, characterized in that: The desulfurization unit includes a desulfurization reactor and a first cyclone dust collector group, and the step C includes: Step C1: the desulfurization reactor obtains the desulfurization agent from the preparation unit; Step C2: the first cyclone dust collector group obtains the sulfur-containing gas from the first-stage cyclone in the kiln tail preheater and collects dust from the sulfur-containing gas; and Step C3: the first cyclone dust collector group transmits the sulfur-containing gas after dust collection to the desulfurization reactor to mix the desulfurizer with the sulfur-containing gas and perform a desulfurization reaction.

32. The self-circulating dry desulfurization method for cement industry according to claim 31, characterized in that: The first cyclone dust collector group includes four cyclone dust collectors.

33. The self-circulating dry desulfurization method for cement industry according to claim 32, characterized in that: The material circulation unit includes a second cyclone dust collector group and a zipper machine, and the step D also includes the following steps: Step D1: the second cyclone dust collector group receives the desulfurized gas from the desulfurization unit and performs dust collection; and Step D2: the zipper machine receives the dust-collected gas from the second cyclone dust collector group and transmits the dust-collected gas to the exhaust gas treatment system or the grinding system.

34. The self-circulating dry desulfurization method for cement industry according to claim 33, characterized in that: The second cyclone dust collector group includes two cyclone dust collectors, and an air inlet end of each of the two cyclone dust collectors is connected to the desulfurization unit, and an air outlet end of each of the two cyclone dust collectors is connected to the zipper machine.

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