Smoke dust removal, desulfurization and water elimination combined treatment device for magnesite calcination vertical kiln

Abstract

The utility model belongs to the field of industrial waste gas treatment, and relates to a magnesite calcination vertical kiln flue gas dust removal, desulfurization and water elimination combined treatment device which comprises a flue gas pretreatment unit, a desulfurization spray tower, a flue gas water elimination unit, an induced draft fan and a bag-type dust remover, a top flue gas outlet of the flue gas pretreatment unit is communicated with a heating medium inlet of the flue gas water elimination unit, a heating medium outlet of the flue gas water elimination unit is communicated with a gas inlet of the desulfurization spray tower, and a top gas outlet of the desulfurization spray tower is communicated with a refrigerant inlet of the flue gas water elimination unit; a refrigerant inlet of the flue gas water eliminating unit is simultaneously connected with a pipeline for introducing outside air, a refrigerant outlet communicated with the flue gas water eliminating unit is communicated with a bag-type dust collector through an induced draft fan, the device adopts the gas-gas heat exchanger, initial high-temperature flue gas heat is recycled, the problems of blockage and corrosion of the current subsequent bag-type dust collector are thoroughly solved, and the service life of the bag-type dust collector is prolonged. And waste of smoke heat is avoided, and energy conservation and environmental protection are achieved.

Description

Technical Field

[0001] The utility model belongs to the field of industrial waste gas treatment, and specifically relates to a magnesite calcining vertical kiln furnace flue gas dust removal, desulfurization, water removal combined treatment device. Background Art

[0002] At present, the traditional vertical kiln furnace for calcining magnesite in China is mainly based on "extensive" production. The backward production process not only causes low production efficiency and poor product quality, but also causes huge waste of energy. Due to the incomplete combustion of fuel, the thermal efficiency of the vertical kiln furnace for calcining magnesite is only 26.47%. The flue gas temperature emitted by the vertical kiln furnace for calcining magnesite can reach above 230℃ at the highest. A large amount of heat is discharged with the thick smoke, and the heat cannot be recycled, resulting in huge waste of energy. In addition, due to the backward production process, the dust content and water content of the flue gas are large, which easily causes the bag filter to paste when it encounters water, and the original flue gas treatment system cannot make the treated flue gas meet the emission standards. At present, small-volume light-burning reverberatory kilns, coke vertical kilns and other calcining equipment will gradually be replaced by rotary kilns, heavy-burning vertical kilns and other equipment, and rotary kilns, externally heated rotary kilns and other equipment will be promoted to replace vertical kilns. However, the cost of replacing large-volume traditional vertical kilns is too high. The state encourages these enterprises to upgrade and transform high-efficiency dust removal and purification technology.

[0003] In recent years, many companies have done a lot of work in the treatment of high-temperature flue gas air pollution in accordance with national requirements, but in general, the results are not very ideal. The high-temperature flue gas dust removal and purification system of the magnesite calcining vertical kiln mostly adopts the bag dust removal treatment method, and the inlet dust concentration requirements of the bag dust collector are limited, and it is suitable for the treatment of dry flue gas with low water content, otherwise it is easy to clog. At present, when the domestic magnesite calcining vertical kiln has a high smoke concentration and contains a large amount of wet steam, it is unreasonable to directly use a bag dust collector. Therefore, a new type of magnesite calcining vertical kiln flue gas dust removal, desulfurization, and water removal combined treatment device is needed. Summary of the invention

[0004] In order to solve the above problems, the utility model discloses a combined treatment device for dust removal, desulfurization and water removal of flue gas from a vertical kiln for calcining magnesite.

[0005] In order to achieve the above object, the technical solution of the utility model is as follows:

[0006] A combined dust removal, desulfurization and water removal treatment device for flue gas of a magnesite calcining vertical kiln furnace comprises a flue gas pretreatment unit, a desulfurization spray tower, a flue gas water removal unit, an induced draft fan and a bag dust collector, wherein the top flue gas outlet of the flue gas pretreatment unit is connected to the heat medium inlet of the flue gas water removal unit, the heat medium outlet of the flue gas water removal unit is connected to the air inlet of the desulfurization spray tower, the top air outlet of the desulfurization spray tower is connected to the refrigerant inlet of the flue gas water removal unit, and the refrigerant inlet of the flue gas water removal unit is simultaneously connected to a pipe for introducing outside air, and the refrigerant outlet connected to the flue gas water removal unit is connected to the bag dust collector via the induced draft fan.

[0007] As a preferred technical solution of the utility model, it also includes a purified liquid spray circulation pump group, a rich liquid storage tank, and a delivery pump. The bottom of the desulfurization spray tower is connected to the rich liquid storage tank, the purified liquid spray circulation pump group is connected to the supernatant of the rich liquid storage tank, and the delivery pump is connected to the solid matter at the bottom of the rich liquid storage tank.

[0008] As a preferred technical solution of the utility model, the bottom ash outlet of the flue gas pretreatment unit is connected to the rich liquid storage tank.

[0009] As a preferred technical solution of the utility model, the flue gas pretreatment unit is a cyclone dust collector.

[0010] As a preferred technical solution of the utility model, the tower body of the desulfurization spray tower is provided with an impact water bath dust removal layer, a water spray layer, an alkali solution spray layer and a water spray layer in sequence from bottom to top.

[0011] As a preferred technical solution of the utility model, the air inlet of the desulfurization spray tower is connected to the impact water bath dust removal layer.

[0012] The beneficial effects of the utility model are:

[0013] 1. While removing dust from flue gas by water film, the desulfurization process is completed, which improves the desulfurization efficiency of the system and reduces operating costs and investment.

[0014] 2. The use of air-to-air heat exchangers to recycle the initial high-temperature flue gas heat, as well as a variety of combined dust removal and water elimination processes, completely solves the current blockage and corrosion problems of subsequent bag dust collectors, avoids the waste of flue gas heat, and saves energy and is environmentally friendly.

[0015] 3. This device does not discharge waste gas or waste water. The spray-purified water and the alkaline solution after adsorption can be directly discharged into the rich liquid storage tank, which can be completely recycled without secondary pollution.

[0016] 4. This device occupies a small area and adopts a new cyclone spray condensation water elimination type wet flue gas desulfurization and dust removal equipment that integrates the flue gas cyclone dust removal, impact water bath dust removal, spray dust removal and flue gas desulfurization treatment principles. It makes full use of the site and the original exhaust gas treatment supporting facilities and pipelines, reduces the length of the pipeline, reduces the pressure drop, and reduces investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of a combined dust removal, desulfurization and water removal treatment device for flue gas from a vertical kiln for calcining magnesite according to the utility model.

[0018] List of Figure Symbols:

[0019] 1. Flue gas pretreatment unit; 2. Desulfurization spray tower; 3. Purification liquid spray circulation pump group; 4. Flue gas water removal unit; 5. Induced draft fan; 6. Bag filter; 7. Rich liquid storage tank; 8. Delivery pump. DETAILED DESCRIPTION

[0020] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to directions in the accompanying drawings, and the words "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0021] like Figure 1 As shown, a combined treatment device for dust removal, desulfurization and water removal of flue gas from a vertical kiln furnace for calcining magnesite includes a flue gas pretreatment unit 1, a desulfurization spray tower 2, a purification liquid spray circulation pump group 3, a flue gas water removal unit 4, an induced draft fan 5, a bag filter 6, a rich liquid storage tank 7, a delivery pump 8 and other devices and accessories. The top flue gas outlet of the flue gas pretreatment unit 1 is connected to the heat medium inlet of the flue gas water removal unit 4, the heat medium outlet of the flue gas water removal unit 4 is connected to the air inlet of the desulfurization spray tower 2, the top air outlet of the desulfurization spray tower 2 is connected to the refrigerant inlet of the flue gas water removal unit 4, and the refrigerant inlet of the flue gas water removal unit 4 is also connected to a pipeline for introducing external air, and the refrigerant outlet connected to the flue gas water removal unit 4 is connected to the bag filter 6 through the induced draft fan 5.

[0022] The bottom of the desulfurization spray tower 2 is connected to the rich liquid storage tank 7, the purified liquid spray circulation pump group 3 is connected to the supernatant of the rich liquid storage tank 7, and the delivery pump 8 is connected to the solid matter at the bottom of the rich liquid storage tank 7, and the bottom ash outlet of the flue gas pretreatment unit 1 is connected to the rich liquid storage tank 7. The waste liquid at the bottom of the desulfurization spray tower 2 is sent to the rich liquid storage tank 7. After settling in the rich liquid storage tank 7 for a period of time, the supernatant is recovered as alkaline liquid and pressurized by the purified liquid spray circulation pump group 3 for spray desulfurization. The solid matter is sent to the magnesite calcining vertical kiln furnace by the volumetric delivery pump 8 as raw material recycling, which fully achieves energy saving, environmental protection, consumption reduction, and no secondary pollution.

[0023] The flue gas pretreatment unit 1 is a cyclone dust collector. The cyclone dust collector is used to pre-treat the high-temperature flue gas. It is a method of using the two dust removal principles of cyclone centrifugal force and liquid washing to improve the dust removal effect. When the dust-laden flue gas enters the dust collector, it first passes through the cyclone part, so that the gas forms a vortex flow in the cyclone. Due to the action of centrifugal force, the particles are thrown off to the wall of the cyclone and fall along the wall, and finally fall into the dust collecting barrel. At the same time, the cyclone dust collector is also provided with a liquid washing part, which further captures and removes the particles in the gas by spraying liquid such as water or chemical agents. When the liquid contacts the dust-laden gas, the particles are adhered to the liquid and discharged with the liquid, thereby achieving the purpose of dust removal. The material of the cyclone dust collector is designed and manufactured with high temperature resistant and scaling resistant stainless steel S31008.

[0024] The tower body of the desulfurization spray tower 2 is provided with an impact water bath dust removal layer, a water spray layer, an alkali solution spray layer, and a water spray layer from bottom to top. The air inlet of the desulfurization spray tower 2 is connected to the impact water bath dust removal layer. The flue gas first enters the impact water bath dust removal layer in the desulfurization spray tower 2, and then undergoes a three-stage combined treatment of water washing, alkali washing, and water washing, and a series flow cooling and absorption process. The water from the impact water bath dust removal layer and the primary and tertiary water washings use purified water, and the secondary alkali washing uses the waste alkali solution after the industrial primary water washing to carry out flue gas desulfurization treatment.

[0025] The smoke dehumidification unit 4 uses an air-to-air heat exchange method to transfer the heat in the smoke to the fresh air entering the device, so that the wet steam in the smoke is condensed and discharged. At the same time, by controlling the temperature and humidity in the device, it can effectively prevent the smoke from generating condensed water again in the subsequent pipeline. The smoke dehumidification unit 4 is designed and manufactured with high temperature and scaling resistant stainless steel S31008.

[0026] The purification liquid spray circulation pump group 3 and the induced draft fan 5 have a motor protection level of IP55 and an insulation level of F. The interfaces connected to the equipment all use flexible connections, and the operating noise is all lower than 85dB(A).

[0027] The working principle of the combined dust removal, desulfurization and water removal treatment device for flue gas from the magnesite calcining vertical kiln:

[0028] Step 1: The high-temperature flue gas at the outlet of the vertical kiln for calcining magnesite is sucked under negative pressure and sent to the flue gas pretreatment unit 1 for dust removal pretreatment to remove large particles of dust therein;

[0029] Step 2: The flue gas after the large dust particles are removed in step 1 is sucked under negative pressure into the desulfurization spray tower 2, and desulfurization is performed in the desulfurization spray tower 2. By spraying the desulfurizer delivered by the purified liquid spray circulation pump group 3 into the flue gas in the desulfurization spray tower 2, the sulfur dioxide in the flue gas reacts chemically with the desulfurizer to generate solid sulfide and precipitate.

[0030] Step 3: The high-temperature flue gas at the outlet of the flue gas pretreatment unit 1 in step 2 is sucked under negative pressure into the flue gas dewatering unit 4 to be used as a heat medium for cooling and heat exchange;

[0031] Step 4: The low-temperature flue gas at the outlet of the desulfurization spray tower 2 in step 3 is sent to the flue gas dewatering unit 4 as a cold medium (a part of the air can be introduced for natural wind cooling if necessary) to exchange heat with the initial high-temperature flue gas to increase the temperature and remove water, so as to completely solve the problem of dew point blockage of the subsequent bag filter;

[0032] Step 5: Use the induced draft fan 5 to suck the outlet flue gas after the air-to-air heat exchange unit is heated and send it to the bag filter 6 for secondary dust removal to achieve standard emission of the flue gas;

[0033] Step 6: The waste liquid at the bottom of the desulfurization spray tower 2 is sent to the rich liquid storage tank 7. After settling in the rich liquid storage tank 7 for a period of time, the supernatant is recycled and used as desulfurization alkali liquid by the purified liquid spray circulation pump group 3 for spray desulfurization. The solid matter is sent to the magnesite calcining vertical kiln furnace by the volumetric delivery pump 8 as raw material recycling, which fully achieves energy saving, environmental protection, consumption reduction, and no secondary pollution.

[0034] In the above steps 2 and 4, high-temperature flue gas and low-temperature flue gas (part of the air can be introduced for natural wind cooling if necessary) are used for heat exchange. High-temperature flue gas cooling: heat energy recovery in high-temperature flue gas is achieved, and water vapor in high-temperature flue gas is condensed and removed when it is cooled; low-temperature flue gas heating: flue gas is heated to above the flue gas water dew point and acid dew point to eliminate water, and reduce the subsequent clogging and corrosion problems of bag filter 6. This ensures the dust removal efficiency of the entire system.

[0035] It should be noted that the above content only illustrates the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.

Claims

1. A combined treatment device for dust removal, desulfurization and water removal of flue gas from a magnesite calcining shaft kiln, comprising a flue gas pretreatment unit (1), a desulfurization spray tower (2), a flue gas water removal unit (4), an induced draft fan (5) and a bag filter (6), characterized in that: The top flue gas outlet of the flue gas pretreatment unit (1) is connected to the heat medium inlet of the flue gas dehumidification unit (4), the heat medium outlet of the flue gas dehumidification unit (4) is connected to the air inlet of the desulfurization spray tower (2), the top air outlet of the desulfurization spray tower (2) is connected to the refrigerant inlet of the flue gas dehumidification unit (4), and the refrigerant inlet of the flue gas dehumidification unit (4) is simultaneously connected to a pipe for introducing external air, and the refrigerant outlet connected to the flue gas dehumidification unit (4) is connected to the bag filter (6) through an induced draft fan (5).

2. The combined dust removal, desulfurization and water removal treatment device for flue gas of a magnesite calcining shaft kiln according to claim 1 is characterized in that: It also includes a purified liquid spray circulation pump group (3), a rich liquid storage tank (7), and a delivery pump (8). The bottom of the desulfurization spray tower (2) is connected to the rich liquid storage tank (7), the purified liquid spray circulation pump group (3) is connected to the supernatant of the rich liquid storage tank (7), and the delivery pump (8) is connected to the solid matter at the bottom of the rich liquid storage tank (7).

3. A combined treatment device for dust removal, desulfurization and water removal of flue gas from a magnesite calcining shaft kiln according to claim 2, characterized in that: The bottom ash outlet of the flue gas pretreatment unit (1) is connected to the rich liquid storage tank (7).

4. The combined dust removal, desulfurization and water removal treatment device for flue gas of a magnesite calcining shaft kiln according to claim 1 is characterized in that: The flue gas pretreatment unit (1) is a hydrocyclone dust collector.

5. The combined dust removal, desulfurization and water removal treatment device for flue gas of a magnesite calcining shaft kiln according to claim 1 is characterized in that: The tower body of the desulfurization spray tower (2) is provided with an impact water bath dust removal layer, a water spray layer, an alkali solution spray layer, and a water spray layer in sequence from bottom to top.

6. A combined dust removal, desulfurization and water removal treatment device for flue gas from a magnesite calcining shaft kiln according to claim 5, characterized in that: The air inlet of the desulfurization spray tower (2) is connected to the impact water bath dust removal layer.

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