A multi-stage, multi-source jet bag-type dust removal and desulfurization system and its use method

Abstract

The present invention discloses a multi-stage, multi-source jet bag-type dust removal and desulfurization system, which relates to the technical fields of energy, chemical industry, environmental protection, etc. It includes a primary mixing jet chamber, a primary dust removal chamber, a secondary mixing jet chamber, a secondary dust removal chamber, a tertiary mixing jet chamber, and a tertiary dust removal chamber. The primary mixing jet chamber, the secondary mixing jet chamber, and the tertiary mixing jet chamber are all provided with a three-phase mixing nozzle. The primary mixing jet chamber, the primary dust removal chamber, the secondary mixing jet chamber, the secondary dust removal chamber, the tertiary mixing jet chamber, and the tertiary dust removal chamber are all provided with an ash hopper. Based on the principle of physical adsorption, the present invention increases the specific surface area of SO3 and smoke dust reaction by spraying a leavening agent or a porous alkaline agent, effectively enhancing the reaction efficiency of smoke dust, alkaline adsorbent, and SO3. The present invention also relates to a method for using this multi-stage, multi-source jet bag-type dust removal and desulfurization system.

Description

Technical Field

[0001] The present invention relates to the technical fields of energy, chemical industry, environmental protection, etc., and more specifically to a multi-stage, multi-source jet bag-type dust removal and desulfurization system. The present invention also relates to a method for using the multi-stage, multi-source jet bag-type dust removal and desulfurization system. Background Art

[0002] Particulate matter (PM), sulfur oxides (SO2, SO3), and nitrogen oxides (NO, NO2) are the main pollutants emitted by coal-fired power plants, among which SO2, NO X As well as particulate matter, SO3, a pollutant with a small total emission volume but which can easily cause serious harm, has gradually attracted the attention of regulatory authorities.

[0003] SO₃, a harmful atmospheric pollutant and a key precursor and molecular component of condensable particulate matter, has not received the attention it deserves for its monitoring and control, and related emissions are not included in existing national standards. Environmentally, SO₃ easily forms submicron aerosols after passing through desulfurization towers, causing some power plant exhaust to appear yellow or blue. Condensation and sedimentation of sulfuric acid aerosols can damage buildings and vegetation, and even cause irreversible damage to the respiratory mucosa and lung structure in humans. In power plant operations, SO₃ reacts with NH₃ in the SCR system to form ammonium sulfate and ammonium bisulfate, causing smoke to clog the air preheater and corrode metals. Ammonium sulfate and ammonium bisulfate also deposit on the surface of SCR catalysts, causing catalyst deactivation and clogging. Furthermore, the presence of SO₃ poses significant challenges to the proper operation of equipment such as the flue gas duct, flue gas cooler, dust collector, and induced draft fan.

[0004] The SO3 emitted by coal-fired power plants mainly comes from two aspects: on the one hand, about 0.5%-1.5% of the sulfur will be oxidized into SO3 during the coal combustion process, and the amount of SO3 generated is directly related to the coal quality (sulfur content, volatile matter, etc.), boiler type, combustion conditions and other factors of the power plant. Under the same conditions, more SO3 is generated when burning bituminous coal than anthracite and lignite; on the other hand, in the SCR denitrification process, under the action of the catalyst, about 1% of the SO2 in the flue gas will be converted into SO3. The actual SO2 / SO3 conversion rate is related to many factors such as the active component content of the catalyst, the catalyst type, the number of catalyst layers and the flue gas conditions. For medium and high sulfur coal, the SO3 concentration in the flue gas at the outlet of the denitrification equipment can reach 150mg / m 3 Even higher.

[0005] The removal of SO3 from flue gas mainly relies on the desulfurization system to remove SO3 at the same time as SO2. In some power plants burning high-sulfur coal, the flue gas injection of alkaline oxides such as CaO is often used to neutralize SO3. However, the high price of alkaline adsorbents, the increase in dust resistivity, the impact on dust removal efficiency, and high operating costs have always plagued power generation companies.

[0006] Therefore, it is necessary to develop a multi-stage, multi-source jet bag dust removal and desulfurization system. Summary of the Invention

[0007] The first purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a multi-stage, multi-source injection bag dust removal and desulfurization system.

[0008] The second purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a method for using a multi-stage, multi-source injection bag dust removal and desulfurization system.

[0009] In order to achieve the above-mentioned first purpose, the technical solution of the present invention is: a multi-stage, multi-source injection bag-type dust removal and desulfurization system, characterized in that: it includes a first-stage mixing injection chamber, a first-stage dust removal chamber, a second-stage mixing injection chamber, a second-stage dust removal chamber, a third-stage mixing injection chamber and a third-stage dust removal chamber arranged in sequence from left to right, and the first-stage mixing injection chamber, the second-stage mixing injection chamber and the third-stage mixing injection chamber are all provided with multi-layer three-phase mixing nozzles, and the bottoms of the first-stage mixing injection chamber, the first-stage dust removal chamber, the second-stage mixing injection chamber, the second-stage dust removal chamber, the third-stage mixing injection chamber and the third-stage dust removal chamber are all provided with ash hoppers, and the alkali solution storage tank and the fluffing agent storage tank are both connected to the top of the three-phase mixing nozzle.

[0010] In the above technical solution, three layers of three-phase mixing nozzles are sequentially arranged in the first-stage mixing injection chamber, the second-stage mixing injection chamber and the third-stage mixing injection chamber from top to bottom.

[0011] In the above technical solution, the three-phase mixing nozzles are arranged to be tilted upward, and the angle between the three-phase mixing nozzles and the wall is 15-75 degrees and can be adjusted at any time.

[0012] In the above technical solution, the ash hopper is equipped with an auxiliary heating facility, which controls the temperature to be 40-70°C and can be adjusted at any time.

[0013] In the above technical solution, the three-phase mixing nozzle can spray solid alkaline compounds, solid leavening agents, alkaline solutions, alkaline gases or alkaline gas-liquid-solid mixtures.

[0014] In order to achieve the above second objective, the technical solution of the present invention is: a method for using a multi-stage, multi-source jet bag-type dust removal and desulfurization system, characterized by comprising the following steps:

[0015] Step 1: Turn on the auxiliary heating facility of the ash hopper to raise the temperature of the ash hopper to above 50°C;

[0016] Step 2: When the dust thickness on the bag in the first-stage dust removal chamber is greater than 5mm, open the three-phase mixing nozzle in the first-stage mixing spray chamber, and the spraying material in the first-stage mixing spray chamber is alkali solution;

[0017] Step 3: When the dust thickness on the bag in the secondary dust removal chamber is greater than 3 mm, the three-phase mixing nozzle in the secondary mixing injection chamber is opened. The injection material in the secondary mixing injection chamber is a solid alkaline compound.

[0018] Step 4: When the smoke concentration in the third-stage dust removal room is greater than 5mg / m 3 The three-phase mixing nozzle in the three-stage mixing spray chamber is opened at the same time, and the spraying substances in the three-stage mixing spray chamber are the leavening agent and the solid alkaline compound;

[0019] Step 5: When the thickness of the sprayed material on the bag in the third-stage dust removal chamber is greater than 5mm, the spraying is stopped and the residual smoke and SO3 are freely adsorbed and accumulated;

[0020] Step 6: When smoke and SO3 emissions are about to exceed the corresponding standards, start the purge systems in the first-level dust removal chamber, the second-level dust removal chamber and the third-level dust removal chamber, and control the purge frequency in the first-level dust removal chamber, the second-level dust removal chamber and the third-level dust removal chamber respectively. The purge frequency of the first-level dust removal chamber is greater than that of the second-level dust removal chamber and the third-level dust removal chamber. After the third-level dust removal chamber is purged, repeat steps 4-5.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1) Based on the principle of physical adsorption, the present invention increases the specific surface area of SO3 and smoke reaction by spraying a bulking agent or a porous alkaline agent, effectively enhancing the reaction efficiency of smoke, alkaline adsorbent and SO3.

[0023] 2) In the present invention, based on the catalytic effect of H2O on the reaction between smoke and SO3, an injection chamber is set in front of each bag-type dust removal chamber, which fully utilizes the synergistic removal effect of SO3 and smoke, and has the advantages of simple equipment, energy-saving system, and low operating cost.

[0024] 3) The injection material in the first-stage mixing injection chamber of the present invention is mainly alkali solution, the injection material in the second-stage mixing injection chamber is mainly solid alkaline compounds, and the injection material in the third-stage mixing injection chamber is mainly leavening agent and porous alkaline compounds; SO3 is fully reacted with H2O and smoke in a graded manner, thereby maximizing the removal effect of SO3 and smoke.

[0025] 4) The nozzles in the injection system at all levels of the present invention adopt an oblique upward impact method, and the fluid and the falling direction of the smoke and dust are impacted, which can make the injection material and the smoke and dust fully react and improve the removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the present invention.

[0027] Figure 2Layout diagram of the three-phase mixing nozzle.

[0028] Figure 3 It is a structural diagram of the prior art.

[0029] Among them, 1-first-stage mixing and injection chamber, 2-first-stage dust removal chamber, 3-second-stage mixing and injection chamber, 4-second-stage dust removal chamber, 5-third-stage mixing and injection chamber, 6-third-stage dust removal chamber, 71-three-phase mixing nozzle, 72-ash hopper, 81-alkali solution storage tank, 82-fluffing agent storage tank, 9-conventional alkali solution injection inlet. DETAILED DESCRIPTION

[0030] The following detailed description of the embodiments of the present invention is given in conjunction with the accompanying drawings, which do not limit the present invention but are merely examples. The advantages of the present invention will become clearer and easier to understand through the description.

[0031] Referring to the accompanying drawings, it can be seen that: a multi-stage, multi-source injection bag dust removal and desulfurization system is characterized in that: it includes a first-stage mixing injection chamber 1, a first-stage dust removal chamber 2, a second-stage mixing injection chamber 3, a second-stage dust removal chamber 4, a third-stage mixing injection chamber 5 and a third-stage dust removal chamber 6 arranged from left to right in sequence, and the first-stage mixing injection chamber 1, the second-stage mixing injection chamber 3 and the third-stage mixing injection chamber 5 are all provided with multi-layer three-phase mixing nozzles 71, and the bottoms of the first-stage mixing injection chamber 1, the first-stage dust removal chamber 2, the second-stage mixing injection chamber 3, the second-stage dust removal chamber 4, the third-stage mixing injection chamber 5 and the third-stage dust removal chamber 6 are all provided with ash hoppers 72, and the alkali solution storage tank 81 and the fluffing agent storage tank 82 are both connected to the top of the three-phase mixing nozzle 71.

[0032] Three layers of three-phase mixing nozzles 71 are sequentially arranged in the first-stage mixing injection chamber 1 , the second-stage mixing injection chamber 3 and the third-stage mixing injection chamber 5 from top to bottom.

[0033] The three-phase mixing nozzles 71 are arranged to be tilted upward. The angle between the three-phase mixing nozzles 71 and the wall is 15-75 degrees and can be adjusted at any time. The three-phase mixing nozzles 71 can spray solid alkaline compounds, solid leavening agents, alkaline solutions, alkaline gases or alkaline gas-liquid-solid mixtures. The sprayed materials and forms are dynamically selected according to process requirements.

[0034] The ash hopper 72 is lined with stainless steel and is equipped with an auxiliary heating facility. The auxiliary heating facility controls the temperature to be 40-70° C. and can be adjusted at any time.

[0035] The three-phase mixing nozzle 71 can spray a solid alkaline compound, a solid leavening agent, an alkaline solution, an alkaline gas, or an alkaline gas-liquid-solid mixture.

[0036] A method for using a multi-stage, multi-source jet bag-type dust removal and desulfurization system, characterized by comprising the following steps:

[0037] Step 1: Turn on the auxiliary heating facility of the ash hopper 72 to raise the temperature of the ash hopper 72 to above 50°C;

[0038] Step 2: When the dust thickness on the bag in the primary dust removal chamber 2 is greater than 5 mm, the three-phase mixing nozzle 71 in the primary mixing spray chamber 1 is opened, and the spraying material in the primary mixing spray chamber 1 is alkali solution;

[0039] Step 3: When the dust thickness on the bag in the secondary dust removal chamber 4 is greater than 3 mm, the three-phase mixing nozzle 71 in the secondary mixing injection chamber 3 is opened. The injection material in the secondary mixing injection chamber 3 is a solid alkaline compound.

[0040] Step 4: When the smoke concentration in the third-stage dust removal chamber 6 is greater than 5 mg / m 3 When the three-phase mixing nozzle 71 in the three-stage mixing spray chamber 5 is opened, the spraying substances in the three-stage mixing spray chamber 5 are the leavening agent and the solid alkaline compound;

[0041] Step 5: When the thickness of the sprayed material on the bag in the third-stage dust removal chamber 6 is greater than 5mm, the spraying is stopped and the residual smoke and SO3 are freely adsorbed and accumulated;

[0042] Step 6: When smoke and SO3 emissions are about to exceed the corresponding standards, start the purge systems in the first-level dust removal chamber 2, the second-level dust removal chamber 4 and the third-level dust removal chamber 6, and control the purge frequency in the first-level dust removal chamber 2, the second-level dust removal chamber 4 and the third-level dust removal chamber 6 respectively. The purge frequency of the first-level dust removal chamber is greater than that of the second-level dust removal chamber and greater than that of the third-level dust removal chamber. After the third-level dust removal chamber is purged, repeat steps 4-5.

[0043] In actual use, the principle of the present invention is that, during long-term operation, it was found that SO3 and smoke dust in flue gas (mainly composed of calcium and aluminum inorganic salts) have a synergistic reaction. That is, during the process of flue gas removal, smoke dust can undergo a series of physical and chemical reactions with SO3, resulting in the environmental protection equipment to remove SO3 while removing smoke dust. The specific mechanism is as follows:

[0044] 1) Physical adsorption reaction:

[0045] Since smoke dust has a certain porosity and specific surface area, part of the smoke dust can adsorb SO3 in the flue gas to a certain extent through intermolecular forces, causing SO3 to be removed together with the smoke dust.

[0046] 2) Chemical adsorption reaction:

[0047] The main components of smoke are mostly inorganic carbonates or aluminosilicates, and SO3 can react directly with them. Taking calcium carbonate as an example, the reaction formula is as follows:

[0048] CaCO3+SO3=CaSO4+CO2

[0049] However, in actual operation, it was further discovered that the synergistic removal effect of SO3 and smoke increased exponentially when the humidity in the flue gas increased. The study found that when the H2O content in the flue gas increased moderately, after SO3 reacted with H2O to form H2SO4, its reaction rate with smoke was greatly accelerated. The reaction formula is as follows:

[0050] SO3+H2O=H2SO4

[0051] CaCO3+H2SO4=CaSO4+CO2+H2O

[0052] In summary, there are three ways to enhance the interaction between SO3 and smoke:

[0053] 1) Enhance physical adsorption reaction: that is, increase the specific surface area (fluffiness) of smoke and powder cake, expand the contact area of SO3 and inorganic salt reaction, and thus enhance the synergistic removal effect of SO3 and smoke.

[0054] 2) Enhance chemical adsorption reaction: Increase the humidity in the flue gas, so that the reaction between gaseous SO3 and inorganic salts is transformed into the reaction between liquid H2SO4 and inorganic salts, thereby increasing the reaction rate and enhancing the synergistic removal effect of SO3 and smoke dust;

[0055] 3) In addition, alkaline adsorbent injection technology can remove most of the SO3, but if the system increases the injection humidity or directly injects alkaline solution, the removal effect will also be enhanced.

[0056] Other parts not described belong to the prior art.

Claims

1. A method for using a multi-stage, multi-source jet bag dust removal and desulfurization system, characterized by: The invention relates to a multi-stage, multi-source jet bag-type dust removal and desulfurization system, comprising a first-stage mixing and jetting chamber (1), a first-stage dust removal chamber (2), a second-stage mixing and jetting chamber (3), a second-stage dust removal chamber (4), a third-stage mixing and jetting chamber (5), and a third-stage dust removal chamber (6) arranged in sequence from left to right, wherein the first-stage mixing and jetting chamber (1), the second-stage mixing and jetting chamber (3), and the third-stage mixing and jetting chamber (5) are all provided with multi-layer three-phase mixing nozzles (71), and the bottoms of the first-stage mixing and jetting chamber (1), the first-stage dust removal chamber (2), the second-stage mixing and jetting chamber (3), the second-stage dust removal chamber (4), the third-stage mixing and jetting chamber (5), and the third-stage dust removal chamber (6) are all provided with ash hoppers (72), and the alkali solution storage tank (81) and the bulking agent storage tank (82) are both connected to the top of the three-phase mixing nozzle (71); The three-phase mixing nozzles (71) are arranged to be tilted upwards, and the angle between the three-phase mixing nozzles (71) and the wall surface is 15-75 degrees and can be adjusted at any time; The injection material in the first-stage mixing and injection chamber is mainly alkali liquid, the injection material in the second-stage mixing and injection chamber is mainly solid alkaline compounds, and the injection material in the third-stage mixing and injection chamber is mainly leavening agent and porous alkaline compounds; SO3 is fully reacted with H2O and smoke in a graded manner, thereby maximizing the removal effect of SO3 and smoke; The ash hopper (72) is equipped with an auxiliary heating facility, which controls the temperature of the ash hopper to 40-70°C and can be adjusted at any time. The method comprises the following steps: Step 1: Turn on the auxiliary heating facility of the ash hopper (72) to raise the temperature of the ash hopper (72) to above 50°C; Step 2: When the thickness of the smoke on the bag in the primary dust removal chamber (2) is greater than 5 mm, the three-phase mixing nozzle (71) in the primary mixing spray chamber (1) is opened, and the spraying material in the primary mixing spray chamber (1) is alkali solution; Step 3: When the thickness of the smoke on the bag in the secondary dust removal chamber (4) is greater than 3 mm, the three-phase mixing nozzle (71) in the secondary mixing injection chamber (3) is opened, and the injection material in the secondary mixing injection chamber (3) is a solid alkaline compound; Step 4: When the smoke concentration in the third-stage dust removal chamber (6) is greater than 5 mg / m 3 When the three-phase mixing nozzle (71) in the three-stage mixing spray chamber (5) is opened, the sprayed substances in the three-stage mixing spray chamber (5) are the leavening agent and the solid alkaline compound; Step 5: When the thickness of the sprayed material on the bag in the third-stage dust removal chamber (6) is greater than 5 mm, the spraying is stopped, and the residual smoke and SO3 are freely adsorbed and accumulated; Step 6: When smoke and SO3 emissions are about to exceed the corresponding standards, the purge systems in the first-stage dust removal chamber (2), the second-stage dust removal chamber (4) and the third-stage dust removal chamber (6) are turned on, and the purge frequencies in the first-stage dust removal chamber (2), the second-stage dust removal chamber (4) and the third-stage dust removal chamber (6) are controlled respectively. The purge frequency of the first-stage dust removal chamber is greater than that of the second-stage dust removal chamber and greater than that of the third-stage dust removal chamber. After the purge of the third-stage dust removal chamber is completed, steps 4-5 are repeated.

2. The method for using a multi-stage, multi-source jet bag dust removal and desulfurization system according to claim 1, characterized in that: Three layers of three-phase mixing nozzles (71) are sequentially arranged in the first-stage mixing injection chamber (1), the second-stage mixing injection chamber (3) and the third-stage mixing injection chamber (5) from top to bottom.

3. The method for using a multi-stage, multi-source jet bag-type dust removal and desulfurization system according to claim 2, characterized in that: The three-phase mixing nozzle (71) can spray a solid alkaline compound, a solid leavening agent, an alkaline solution, an alkaline gas or an alkaline gas-liquid-solid mixture.

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