CN210206434U - Wet desulphurization device for resource utilization of semidry desulphurization ash - Google Patents

Wet desulphurization device for resource utilization of semidry desulphurization ash Download PDF

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CN210206434U
CN210206434U CN201920746148.8U CN201920746148U CN210206434U CN 210206434 U CN210206434 U CN 210206434U CN 201920746148 U CN201920746148 U CN 201920746148U CN 210206434 U CN210206434 U CN 210206434U
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desulfurization
ash
slurry
tower
oxidation
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Wei Liu
刘伟
Hong Jiang
蒋红
Zhiguo Yang
杨志国
Yongping Mei
梅永平
Zhi Sun
孙陟
Jiangping Qi
戚江平
Le Qin
秦乐
Xiaoyu Chen
陈晓雨
Chengjia Wu
武承甲
Lei Zhu
朱磊
Hao Pan
潘浩
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Xinjiang Tianfu Environmental Protection Technology Co Ltd
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Xinjiang Tianfu Environmental Protection Technology Co Ltd
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Abstract

The utility model discloses a wet desulphurization device for resource utilization of semidry desulphurization ash, which is characterized by comprising a desulphurization washing mechanism, a desulphurization ash pulping mechanism and an oxidation concentration mechanism, wherein the desulphurization washing mechanism at least comprises a desulphurization tower (1), a desulphurization circulating pump (2), a desulphurization ash slurry spray pump (6) and a gypsum slurry spray pump (9); the desulfurization ash pulping mechanism at least comprises a desulfurization ash pulping tank (3), a desulfurization mortar liquid pump (4) and a desulfurization mortar liquid storage tank (5); the oxidation concentration mechanism at least comprises an oxidation tower (7), an oxidation fan (8) and a gypsum discharge pump (10). Compared with the prior art, the utility model discloses a wet flue gas desulfurization technology has solved semi-dry desulfurization ash resource utilization difficult problem, improves wet flue gas desulfurization device purification efficiency when reducing wet flue gas desulfurization device running cost and reduction energy consumption to system secondary pollution is little.

Description

Wet desulphurization device for resource utilization of semidry desulphurization ash
Technical Field
The utility model relates to a wet flue gas desulfurization device of semi-dry process desulfurization ash utilization belongs to resource and environmental protection field.
Background
The flue gas desulfurization mainly adopts wet, dry and semi-dry processes. Compared with a wet desulphurization process, the semi-dry process has the advantages of less investment, small occupied area, water and energy conservation and no pollution of waste water and waste acid, so the semi-dry process is deeply welcomed by industries such as medium and small power plants, metallurgical sintering, heating and heat supply, chemical building materials and the like. In the operation process of the semi-dry desulfurization device, high-temperature raw flue gas carrying a large amount of dust particles is contacted with fine fog drops of atomized desulfurizer slurry, so that acid gases such as SOX, HCl and HF in the flue gas are quickly reacted with the fog drops of alkaline slurry for heat exchange to complete removal of the acid gases, and the fog drops of the desulfurizer slurry are evaporated to dryness by the flue gas and are captured by a dust remover along with the dust particles in the flue gas to form a semi-dry desulfurization byproduct, namely desulfurization ash. The semi-dry flue gas desulfurization ash is light gray powder, is like cement in appearance, has the water content of 1-5 percent (the average value is 3 percent), the bulk density of 0.55-1.0 t/m3 and the true density of 2.25-2.69 t/m 3. The particle size of the desulfurized fly ash is small, and the majority of the particle sizes are concentrated below 20 um. The semidry desulfurization ash consists of calcium sulfite, calcium sulfate, calcium carbonate, calcium hydroxide, a small amount of calcium chloride, calcium fluoride and fly ash, wherein the content of CaO and SO3 is high. In addition, the desulfurized fly ash also contains a large amount of aluminum oxides and silicon oxides and a plurality of heavy metal elements, such as Zn, Cu, Cd, Mo, Cr, Mn, Ni and the like.
A great deal of calcium sulfite (CaSO) in semi-dry desulfurized fly ash3) And unreacted calcium oxide (CaO) seriously limits the utilization mode and range of semi-dry desulfurized fly ash, and a large amount of calcium sulfite (CaSO)3) The semi-dry desulfurized fly ash is unstable in property, and the excessively high CaO causes higher alkalinity of the desulfurized fly ash and greater harm to the environment. The semidry desulfurized fly ash can only be used for backfilling or stacking in the open air at present, not only occupies a large amount of land and causes underground water pollution, but also flies everywhere to pollute air once blown by wind due to small density and light weight; if the water is not properly used, serious secondary pollution can be caused to the environment and water sources. About 2000 million tons of desulfurized ash are discharged every year in China, and a large amount of semidry desulfurized ash cannot be treated. The desulfurization process generates new pollution while desulfurizing, and forms a vicious circle.
The semidry desulfurization ash is used for wet desulfurization and is used as a desulfurizer of a wet desulfurization device, and calcium sulfite (CaSO) in the desulfurization ash can be completely oxidized by utilizing an oxidation system of a desulfurization tower3) And can also release calcium sulfite (CaSO) during oxidation3) Coated calcium oxide (CaO) and using alkali of the calcium oxide (CaO)The desulfurized fly ash can be used as a wet desulfurizing agent for desulfurization, and the resource utilization of the semidry desulfurized fly ash can be realized at lower cost. However, the direct use of the semidry desulfurization ash in a wet desulfurization system has the following problems: (1) the semidry desulfurization ash contains a large amount of amphoteric oxides such as aluminum oxide, silicon oxide and the like, and the desulfurization agent particles are wrapped in the wet desulfurization process, so that the dehydration difficulty of desulfurization byproducts is increased; (2) and most of calcium sulfite (CaSO) generated in the semi-dry desulphurization process3) The total desulfurization capacity of the desulfurization mortar liquid is low, and SO in the flue gas is2When the concentration is higher, the desulfurization efficiency of a wet desulfurization system can be reduced; (3) the desulfurization ash contains a large amount of organic matters and heavy metals, and the semi-dry desulfurization ash is directly used for wet desulfurization, so that the purity of by-product gypsum and the treatment difficulty of desulfurization wastewater are reduced.
Therefore, the utility model provides a wet flue gas desulfurization device of semi-dry desulfurization ash resource utilization realizes calcium sulfite (CaSO) in semi-dry desulfurization ash3) And the calcium oxide (CaO) is completely recycled, so that the treatment effect of the wet desulphurization device is improved, and the operation cost of the wet desulphurization device is greatly reduced.
Disclosure of Invention
The utility model aims at providing a wet flue gas desulfurization device of semi-dry desulfurization ash utilization, with wet flue gas desulfurization tower through have rise gas and connect two absorption sections about the liquid tank layer divide into of liquid function, semi-dry desulfurization ash and gypsum filtrating and the semi-dry desulfurization mortar liquid that supplements the process water preparation are used for the desulfurization of upper end low sulfur flue gas, spray the porous sheet layer of layer below through the desulfurization ash thick liquid and strengthen calcium sulfite in the desulfurization ash (CaSO)3) Oxidizing and dissolving out calcium oxide (CaO), extracting high-purity gypsum by combining with a high-efficiency oxidation tower with a layered suspension separation function, and realizing calcium sulfite (CaSO) in semidry desulfurization ash3) And the calcium oxide (CaO) is completely recycled, so that the treatment effect of the wet desulphurization device is improved, and the operation cost of the wet desulphurization device is greatly reduced.
In order to achieve the above object, the present invention provides the following technical solutions:
the utility model provides a wet flue gas desulfurization device of semi-dry desulfurization ash utilization, its characterized in that, includes desulfurization washing mechanism, desulfurization ash slurrying mechanism and oxidation concentration mechanism, wherein:
the desulfurization washing mechanism at least comprises a desulfurization tower (1), a desulfurization circulating pump (2), a desulfurization ash slurry spraying pump (6) and a gypsum slurry spraying pump (9), wherein an air inlet (1-1) and an air outlet (1-9) are arranged on the desulfurization tower (1), the part below the air inlet (1-1) in the desulfurization tower (1) is a desulfurization slurry pool, and a desulfurization spraying layer (1-2), a first-stage demister layer (1-3), a liquid returning groove layer (1-4), a porous plate layer (1-5), a desulfurization ash slurry spraying layer (1-6), a gypsum slurry spraying layer (1-7) and a second-stage demister layer (1-8) are sequentially arranged between the air inlet (1-1) and the air outlet (1-9) in the desulfurization tower (1) along the flowing direction of flue gas;
the desulfurization ash pulping mechanism at least comprises a desulfurization ash pulping tank (3), a desulfurization mortar liquid pump (4) and a desulfurization mortar liquid storage tank (5);
the oxidation concentration mechanism at least comprises an oxidation tower (7), an oxidation fan (8) and a gypsum discharge pump (10).
Further, the inlet of the desulfurization mortar liquid pump (4) is communicated with the bottom of the desulfurization ash slurry tank (3) through a pipeline, the outlet of the desulfurization mortar liquid pump is communicated with the top of the desulfurization mortar liquid storage tank (5) through a pipeline, the bottom of the desulfurization mortar liquid storage tank (5) is connected with the desulfurization ash slurry spraying layers (1-6) through a desulfurization ash slurry spraying pump (6), the inlet of the gypsum slurry spraying pump (9) is communicated with the upper part of the oxidation tower (7), and the outlet of the gypsum slurry spraying pump (9) is communicated with the gypsum slurry spraying layers (1-7); the inlet of the desulfurization circulating pump (2) is communicated with the slurry tank of the desulfurization tower (1) through a pipeline, and the outlet of the desulfurization circulating pump is communicated with the desulfurization spraying layer (1-2) through a pipeline.
Furthermore, a gypsum filtrate pipe (3-1), a desulfurized ash conveying pipe (3-2) and a process water conveying pipe (3-3) are arranged above the desulfurized ashed slurry tank (3), and stirring devices are arranged in the desulfurized ashed slurry tank (3) and the desulfurized slurry storage tank (5).
Further, the oxidation tower (7) is of a sealing structure, the inside of the tower body is provided with a gas distribution disc (7-1) which can divide an inner cavity of the oxidation tower (7) into an upper cavity and a lower cavity which can be communicated, the side wall of the oxidation tower (7) above the gas distribution disc (7-1) is provided with a liquid outlet (7-2) and a liquid outlet communicated with an inlet of a gypsum slurry spray pump (9), the side wall of the oxidation tower (7) below the gas distribution disc (7-1) is provided with a gas inlet, the gas inlet is communicated with an outlet of an oxidation fan (8), the top of the oxidation tower (7) is provided with an exhaust passage (7-3) communicated with the gas inlet (1-1) of the desulfurization tower (1), and the bottom of the oxidation tower (7) is communicated with an inlet of the gypsum discharge pump (10) through a pipeline.
Further, the gas distribution disc (7-1) is a plate-shaped body provided with a plurality of openings, the aperture of each opening is 5-20 mm, the opening rate is 30-50%, namely the total area of the openings is 30-50% of the surface area of the gas distribution disc (7-1), and the gas distribution disc (7-1) is positioned at the 1/3-1/2 height of the oxidation tower (7).
Further, the liquid return groove layer (1-4) is arranged above the first-stage demister layer (1-3) and below the porous plate layer (1-5), an air-lifting liquid return device is arranged in the liquid return groove layer (1-4) and used for lifting air flow below and collecting and discharging slurry above the air flow out of the desulfurizing tower (1), a liquid discharge port communicated with the outside of the tower is formed in the liquid return groove layer (1-4), and the liquid discharge port of the liquid return groove layer (1-4) is communicated with the top of the oxidizing tower (7) through a pipeline.
Further, porous plate layer (1-5) are located the top of returning the bath layer (1-4), and the desulfurization ash thick liquid sprays the below on layer (1-6), porous plate layer (1-5) contain a plurality of layers be equipped with the porous plate of trompil (11), the aperture of trompil (11) is 10mm ~ 20mm, the total area of trompil (11) is 15% ~ 40% of desulfurizing tower (1) cross sectional area, as preferred, the porous plate sets up the number of piles and is 1 ~ 2 layers.
A wet desulphurization method for resource utilization of semi-dry desulphurization ash is implemented by using the above wet desulphurization device for resource utilization of semi-dry desulphurization ash, and specifically comprises the following steps:
a. the flue gas enters from a gas inlet (1-1) of the desulfurizing tower (1) and is in reverse contact washing with the spraying slurry of the desulfurizing spraying layer (1-2) to finish primary washing and desulfurizing;
b. the flue gas after primary desulfurization upwards passes through the primary demister layer (1-3) for demisting to form low-sulfur flue gas which flows upwards and sequentially passes through the liquid return tank layer (1-4), the porous plate layer (1-5), the desulfurized ash slurry spraying layer (1-6) and the gypsum slurry spraying layer (1-7) for deep desulfurization,
wherein the semi-dry desulfurized fly ash, the gypsum filtrate and the process water are delivered into a desulfurized ashed slurry tank (3) through a delivery pipeline, the semi-dry desulfurized fly ash slurry with the desulfurized ash content concentration of 5 to 15 percent is prepared under the stirring action of a stirrer in the desulfurized ashed slurry tank (3) and is delivered into a desulfurized fly ash slurry storage tank (5) through a desulfurized fly ash slurry liquid pump (4) for storage, alkaline components such as CaO and the like in the desulfurized fly ash are dissolved out to form high-pH slurry, the desulfurized fly ash slurry liquid is delivered into desulfurized fly ash slurry spraying layers (1 to 6) for atomization through a desulfurized fly ash slurry spraying pump (6) from the desulfurized fly ash slurry storage tank (5), the atomized desulfurized fly ash slurry liquid is reversely contacted and washed with the low-sulfur flue gas which is subjected to preliminary washing and desulfurization, and the dissolved alkaline components such as CaO and the3
c. The low pH desulfurized ash slurry after the spraying, washing and desulfurization falls into the porous plate layer (1-5) under the action of gravity, and forms a gas-liquid turbulent layer with the upward flue gas passing through the holes of the porous plate, and the CaSO in the desulfurized ash slurry3Is oxidized by contacting with oxygen in the flue gas to generate CaSO4Gypsum slurry is formed and finally falls into a liquid return tank layer (1-4) and is guided into an oxidation tower (7) through a liquid outlet;
d. oxidizing air is fed into the oxidation tower (7) through an oxidizing fan (8) to remove the residual CaSO in the gypsum slurry3The oxidation is carried out, the air distribution mode of the oxidation fan (8) is pipe network air distribution, the air distribution disc (7-1) in the oxidation tower (7) carries out layered isolation on gypsum slurry while breaking air bubbles of oxidation, gypsum particles with high density sink to the bottom of the oxidation tower (7) below the air distribution disc (7-1), and the gypsum particles are discharged by a gypsum discharge pump (10) and dehydrated to prepare high-purity gypsum; low density of impurities of desulfurized fly ash, CaSO3CaO and other components are suspended in a cavity on the upper part of the oxidation tower (7) above the air distribution disc (7-1) under the influence of ascending air flow, and are sent to a gypsum slurry spraying layer (1-7) by a gypsum slurry spraying pump (9) for continuous washing, oxidation and layering, and the rest impurities are discharged from a liquid discharge port (7-2) at the upper end of the side wall of the oxidation tower (7);
e. and the clean flue gas after deep desulfurization is demisted by the secondary demister layers (1-8) and then discharged from the gas outlet (1-9) of the desulfurizing tower (1), and finally the resource utilization of the semi-dry desulfurization ash is realized.
Further, the retention time of the slurry in the oxidation tower (7) is 15-40 min.
Further, the liquid-gas ratio of the desulfurized fly ash slurry spraying layer (1-6) is 1-3L/Nm3The coverage rate of the spraying layer is 200-350%; the liquid-gas ratio of the gypsum slurry spraying layer (1-7) is 2-5L/Nm3The coverage rate of the spraying layer is 150-250%.
Compared with the prior art, the utility model discloses following beneficial effect has:
(1) the utility model provides a solution of semi-dry desulfurization ash resource utilization, directly be used for wet flue gas desulfurization with semi-dry desulfurization ash, utilize wet flue gas desulfurization device oxidation CaSO3And the dissolved CaO is used as a desulfurizer for wet desulphurization, and finally CaSO is used3And CaO are converted into gypsum capable of being recycled, so that the running cost of the wet desulphurization device is reduced while the problem of recycling of semi-dry desulphurization ash is solved;
(2) the utility model provides a solution for improving the purification efficiency of a wet desulphurization device by using semi-dry desulphurization ash, which uses the desulphurization mortar liquid with higher pH but low desulphurization capacity for purifying low-sulfur flue gas which has already finished preliminary desulphurization, and realizes the resource utilization of the semi-dry desulphurization ash while greatly improving the purification efficiency of the low-sulfur flue gas;
(3) the utility model provides a solution that semi-dry desulfurization ash utilization was realized to low energy consumption, through setting up the porous plate layer, utilize updraft gas stream and semi-dry desulfurization ash to spray the turbulent layer that the thick liquid formed above the porous plate layer, reinforce CaSO3Oxidation and dissolution desulfurization of CaO, reduction of CaSO in desulfurized fly ash3The purification efficiency of the wet desulphurization tower is greatly improved while the energy consumption of oxidation is reduced;
(4) the utility model provides a semidry desulfurization ash resource utilization scheme that secondary pollution is little utilizes gypsum filtrating as the slurrying water of semidry desulfurization ash to divide into two sections absorptions with the desulfurizing tower, the effectual influence of amphoteric oxide and heavy metal to wet flue gas desulfurization system and accessory substance in having avoided the desulfurization ash improves the whole purification efficiency of desulphurization unit, only needs to manage the waste water that reason oxidation tower leakage fluid dram discharged, and system secondary pollution is little.
Drawings
Fig. 1 is a schematic structural diagram of the present invention;
fig. 2 is a schematic structural diagram of the perforated plate of the present invention.
Shown in the figure: 1 is a desulfurizing tower, 1-1 is an air inlet, 1-2 is a desulfurizing spray layer, 1-3 is a first-stage demister layer, 1-4 is a liquid return tank layer, 1-5 is a porous plate layer, 1-6 is a desulfurizing ash slurry spray layer, 1-7 is a gypsum slurry spray layer, 1-8 is a second-stage demister layer, 1-9 is an air outlet, 2 is a desulfurizing circulating pump, 3 is a desulfurizing ash slurry tank, 3-1 is a gypsum filtrate pipe, 3-2 is a desulfurizing ash conveying pipe, 3-3 is a process water conveying pipe, 4 is a desulfurizing mortar liquid pump, 5 is a desulfurizing mortar liquid storage tank, 6 is a desulfurizing ash slurry spray pump, 7 is an oxidizing tower, 7-1 is an air distribution disc, 7-2 is a liquid outlet, 7-3 is an exhaust passage, 8 is an oxidizing fan, 9 is a gypsum slurry spray pump, 10 is a gypsum discharge pump, and 11 is an opening.
Detailed Description
The preferred embodiments of the present invention will be described in detail below.
Example 1: referring to fig. 1 and 2, for the structure of embodiment 1 of the present invention,
the utility model provides a wet flue gas desulfurization device of semi-dry desulfurization ash utilization, includes desulfurization washing mechanism, desulfurization ash slurrying mechanism and oxidation concentration mechanism, wherein:
the desulfurization washing mechanism at least comprises a desulfurization tower 1, a desulfurization circulating pump 2, a desulfurization ash slurry spraying pump 6 and a gypsum slurry spraying pump 9, wherein the desulfurization tower 1 is provided with an air inlet 1-1 and an air outlet 1-9, and a desulfurization spraying layer 1-2, a primary demister layer 1-3, a liquid return tank layer 1-4, a porous plate layer 1-5, a desulfurization ash slurry spraying layer 1-6, a gypsum slurry spraying layer 1-7 and a secondary demister layer 1-8 are sequentially arranged between the air inlet 1-1 and the air outlet 1-9 in the desulfurization tower 1 along the flowing direction of flue gas; the inlet of the desulfurization circulating pump 2 is communicated with the slurry tank of the desulfurization tower 1 through a pipeline, and the outlet of the desulfurization circulating pump 2 is communicated with the desulfurization spraying layer 1-2 through a pipeline. The liquid return tank layer 1-4 is arranged above the first-stage demister layer 1-3 and below the porous plate layer 1-5, an air-lifting liquid return device is arranged in the liquid return tank layer 1-4 and used for lifting air flow below and collecting and discharging slurry above the air flow out of the desulfurizing tower 1, a liquid discharge port communicated with the outside of the tower is arranged on the liquid return tank layer 1-4, and the liquid discharge port of the liquid return tank is communicated with the top of the oxidizing tower 7 through a pipeline. Porous plate layer 1-5 is located the top of returning the bath layer 1-4, and the desulfurization ash thick liquid sprays the below on layer 1-6, porous plate layer 1-5 contains a plurality of layers and is equipped with the perforated plate of trompil 11, the aperture of trompil 11 is 10mm ~ 20mm, the total area of trompil 11 is 15% ~ 40% of desulfurizing tower 1 cross sectional area, as preferred, the perforated plate sets up the number of piles and is 1 ~ 2 layers.
The desulfurization ash pulping mechanism at least comprises a desulfurization ash pulping tank 3, a desulfurization mortar liquid pump 4 and a desulfurization ash slurry storage tank 5;
the inlet of the desulfurization mortar liquid pump 4 is communicated with the bottom of the desulfurization ashing slurry tank 3 through a pipeline, the outlet of the desulfurization mortar liquid pump is communicated with the top of a desulfurization mortar liquid storage tank 5 through a pipeline, the bottom of the desulfurization mortar liquid storage tank 5 is connected with desulfurization mortar liquid spraying layers 1-6 through a desulfurization mortar liquid spraying pump 6, the inlet of the gypsum slurry spraying pump 9 is communicated with the upper part of an oxidation tower 7, and the outlet of the gypsum slurry spraying pump 9 is communicated with the gypsum slurry spraying layers 1-7; and a gypsum filtrate pipe 3-1, a desulfurized ash conveying pipe 3-2 and a process water conveying pipe 3-3 are arranged above the desulfurized ashing slurry tank 3, and stirring devices are arranged in the desulfurized ashing slurry tank 3 and the desulfurized ash slurry storage tank 5.
The oxidation concentration mechanism at least comprises an oxidation tower 7, an oxidation fan 8 and a gypsum discharge pump 10.
The oxidation tower 7 is of a sealing structure, an air distribution disc 7-1 which can divide an inner cavity of the oxidation tower 7 into an upper cavity and a lower cavity which can be communicated is arranged in the tower body, a liquid outlet 7-2 and a liquid outlet communicated with a gypsum slurry spray pump 9 are arranged on the side wall of the oxidation tower 7 above the air distribution disc 7-1, an air inlet is arranged on the side wall of the oxidation tower 7 below the air distribution disc 7-1 and is connected with an oxidation fan 8, an exhaust passage 7-3 communicated with the air inlet 1-1 of the desulfurization tower 1 is arranged at the top of the oxidation tower 7, and the bottom of the oxidation tower 7 is communicated with a gypsum discharge pump 10 through a pipeline.
The gas distribution disc 7-1 is a plate-shaped body provided with a plurality of openings, the aperture of each opening is 5-20 mm, the opening rate is 30-50%, and the gas distribution disc 7-1 is positioned at the 1/3-1/2 height of the oxidation tower 7.
In actual use: the sulfur-containing flue gas enters from a gas inlet 1-1 on the side wall of the lower end of a desulfurizing tower 1 and moves upwards, the desulfurizing circulating liquid in a desulfurizing slurry pool is sent to a desulfurizing spraying layer 1-2 by a desulfurizing circulating pump 2, the desulfurizing circulating liquid flows downwards after being sprayed and atomized by the desulfurizing spraying layer 1-2 and reacts with the sulfur-containing flue gas in a reverse contact way, and most of SO in the flue gas2Is absorbed by the spraying slurry, the flue gas finishes preliminary desulfurization and exchanges heat with the spraying slurry for cooling, the flue gas which finishes preliminary desulfurization continues to flow upwards after demisting and desizing by the first-level demister layer 1-3, sequentially passes through the liquid return tank layer 1-4, the porous plate layer 1-5, the desulfurization ash slurry spraying layer 1-6 and the gypsum slurry spraying layer 1-7 for deep desulfurization and purification, and the flue gas which finishes deep desulfurization and purification is demisted by the second-level demister layer 1-8 and then is discharged from the gas outlet 1-9 at the top of the desulfurizing tower 1.
The gypsum filtrate pipe 3-1 and the desulfurized fly ash conveying pipe 3-2 convey the gypsum filtrate and the semidry desulfurized fly ash into the desulfurized fly ash slurry tank 3 to be prepared into desulfurized fly ash slurry with desulfurized fly ash mass concentration of 5-15%, a stirrer is arranged in the desulfurized fly ash slurry tank 3 and is used for uniformly stirring the desulfurized fly ash slurry, and when the gypsum filtrate is insufficient, process water is supplemented into the desulfurized fly ash slurry tank 3 through the process water conveying pipe 3-3, so that the desulfurized fly ash concentration in the slurry can meet the requirement. The prepared desulfurization ash slurry is sent to a desulfurization ash slurry storage tank 5 by a desulfurization ash slurry pump 4, and a stirrer is arranged in the desulfurization ash slurry storage tank 5 to prevent slurry sedimentation and promote the dissolution of CaO in the desulfurization ash so as to increase the pH value of the desulfurization ash slurry in the desulfurization ash slurry storage tank 5.
The higher pH desulfurized fly ash slurry carries a large amount of CaSO3CaO, amphoteric oxide, heavy metal and the like are sent to the desulfurization ash slurry spraying layers 1-6 by the desulfurization ash slurry spraying pump 6 for spraying and atomizing, and are in reverse contact with low-sulfur flue gas flowing upwards along the desulfurization tower 1, and the dissolved CaO in the desulfurization ash slurry and residual SO in the flue gas2Reaction to produce CaSO3And meanwhile, the flue gas realizes deep purification. Finish the dewatering of the spray washingThe sulfur ash slurry falls into the porous plate layer 1-5 under the action of gravity, and forms a gas-liquid turbulent layer with the perforation airflow above the porous plate layer 1-5 under the action of the high-speed airflow ascending through the pores of the porous plate layer 1-5. Under gas-liquid disturbance, the original CaSO in the desulfurized fly ash3And washing CaSO generated in the spray desulfurization process3Contacting with oxygen in the flue gas, oxidizing and releasing the coated CaO; meanwhile, strong gas-liquid turbulence promotes the dissolution of CaO, and the flue gas desulfurization efficiency of the turbulent layer is improved. Most of CaSO in desulfurized fly ash3CaO is converted into byproduct gypsum in oxidation, dissolution and desulfurization reactions of the gas-liquid turbulent layer to form gypsum slurry.
The gypsum slurry carries a small amount of CaSO that has not been converted3CaO passes through the porous plate layers 1-5 and falls into the liquid return tank layers 1-4 under the action of gravity, and is discharged into the oxidation tower 7 through the liquid return tank layers 1-4 by a pipeline. The oxidation air is sent into an air distribution pipe network below the oxidation tower 7 by an oxidation fan 8, is broken into bubbles by the air distribution pipe network and floats upwards under the action of buoyancy force to treat CaSO remained in the gypsum slurry3Deep oxidation is carried out, and meanwhile, the gypsum slurry is subjected to suspension stirring. The middle part of the oxidation tower 7 is provided with a gas distribution disc 7-1 provided with a plurality of small holes and used for crushing floating bubbles to provide gas-liquid contact area and stratify gypsum slurry, and the gypsum crystal particles which finish oxidation crystallization have higher density, fall under the gas distribution disc 7-1 under the action of gravity and are in a suspension state under the action of oxidation air; CaSO in desulfurized fly ash3The particle size and density of CaO, amphoteric oxide and heavy metal fine particles are small, the CaO, amphoteric oxide and heavy metal fine particles are in a suspension state above the air distribution disc 7-1 under the buoyancy action of oxidation air, and the pH value of the gypsum slurry subjected to two-stage oxidation is reduced to 4.5-6.0. The upper layer gypsum slurry after deep oxidation in the oxidation tower 7 contains a small amount of unreacted CaO, is sent to the gypsum slurry spraying layers 1-7 by a gypsum slurry spraying pump 9 for atomization, and continuously reacts with sulfur-containing flue gas, and simultaneously avoids the phenomenon of scaling caused by the slurry of the desulfurization ash slurry spraying layers 1-6 with higher pH in the desulfurization tower 1; amphoteric oxide and heavy metal particles in the gypsum slurry are discharged from a liquid outlet 7-2 on the side wall of the oxidation tower; the gypsum slurry after settling and concentration is sent to a dewatering system by a gypsum discharge pump 10 for dewatering to prepare high-purity gypsum, and the gypsum is dewatered and filteredThe liquid is sent to a desulfurization and ashing slurry tank 3 through a pipeline. To prevent SO caused by too low pH during oxidation2And the top of the oxidation tower 7 is provided with an exhaust channel 7-3 communicated with the air inlet 1-1 of the desulfurizing tower 1 for feeding oxidized air which is oxidized into the desulfurizing tower 1.
Example 2: a wet desulphurization method for resource utilization of semidry desulphurization ash specifically comprises the following steps:
a. the sulfur-containing flue gas enters from a gas inlet 1-1 on the side wall of the lower end of a desulfurizing tower 1 and moves upwards, the desulfurizing circulating liquid in a desulfurizing slurry pool is sent to a desulfurizing spraying layer 1-2 by a desulfurizing circulating pump 2, the desulfurizing circulating liquid flows downwards after being sprayed and atomized by the desulfurizing spraying layer 1-2 and is in reverse contact with the sulfur-containing flue gas for washing, and most of SO in the flue gas2Absorbed by the spraying slurry to finish preliminary washing desulfurization and exchange heat with the spraying slurry for cooling;
b. the flue gas after primary desulfurization upwards passes through the first-stage demister layer 1-3 for demisting to form low-sulfur flue gas which flows upwards and sequentially passes through the liquid return tank layer 1-4, the porous plate layer 1-5, the desulfurized ash slurry spraying layer 1-6 and the gypsum slurry spraying layer 1-7 for deep desulfurization,
the gypsum filtrate pipe 3-1 and the desulfurized fly ash conveying pipe 3-2 convey the gypsum filtrate and the semidry desulfurized fly ash into the desulfurized fly ash slurry tank 3 to be prepared into desulfurized fly ash slurry with desulfurized fly ash mass concentration of 5-15%, a stirrer is arranged in the desulfurized fly ash slurry tank 3 and is used for uniformly stirring the desulfurized fly ash slurry, and when the gypsum filtrate is insufficient, process water is supplemented into the desulfurized fly ash slurry tank 3 through the process water conveying pipe 3-3, so that the desulfurized fly ash concentration in the slurry can meet the requirement. The prepared desulfurization slurry is sent to a desulfurization slurry storage tank 5 by a desulfurization slurry pump 4 and stored, and a stirrer is provided in the desulfurization slurry storage tank 5 to prevent slurry sedimentation and promote the dissolution of CaO in the desulfurization ash, thereby increasing the pH of the desulfurization slurry in the desulfurization slurry storage tank 5.
The higher pH desulfurized fly ash slurry carries a large amount of CaSO3CaO, amphoteric oxide, heavy metal and the like are sent to the desulfurization ash slurry spraying layer 1-6 from the desulfurization ash slurry storage tank 5 through the desulfurization ash slurry spraying pump 6 for spraying and atomizing, and are reversely contacted with low-sulfur flue gas flowing upwards along the desulfurization tower 1, so that the desulfurization ash slurry is dissolvedCaO of (2) and residual SO in flue gas2Reaction to produce CaSO3And meanwhile, the flue gas realizes deep purification.
c. The low pH desulfurized ash slurry after being sprayed and washed falls into the porous plate layer 1-5 under the action of gravity, and forms a gas-liquid turbulent layer above the porous plate layer 1-5 together with the upward flue gas passing through the open pores of the porous plate layer 1-5 under the action of the high-speed airflow rising through the pores of the porous plate layer 1-5, and the original CaSO in the desulfurized ash is disturbed by the gas and liquid3And washing CaSO generated in the spray desulfurization process3Is oxidized by contacting with oxygen in the flue gas to generate CaSO4Releasing the wrapped CaO; meanwhile, strong gas-liquid turbulence promotes the dissolution of CaO, and the flue gas desulfurization efficiency of the turbulent layer is improved. Most of CaSO in desulfurized fly ash3CaO is converted into byproduct gypsum in oxidation, dissolution and desulfurization reactions of the gas-liquid turbulent layer to form gypsum slurry, and the gypsum slurry carries a small amount of CaSO which is not converted3CaO passes through the porous plate layers 1-5 and falls into the liquid return tank layers 1-4 under the action of gravity, and is discharged into the oxidation tower 7 through the liquid return tank layers 1-4 by a pipeline;
d. the oxidation air is sent into the air distribution pipe network below the oxidation tower 7 by the oxidation fan 8, and the oxidation air is broken into bubbles by the air distribution pipe network and floats upwards under the action of buoyancy to treat the CaSO remained in the gypsum slurry3Deep oxidation is carried out, and meanwhile, the gypsum slurry is subjected to suspension stirring. The middle part of the oxidation tower 7 is provided with a gas distribution disc 7-1 provided with a plurality of small holes and used for crushing floating bubbles to provide gas-liquid contact area and stratify gypsum slurry, and the gypsum crystal particles which finish oxidation crystallization have higher density, fall under the gas distribution disc 7-1 under the action of gravity and are in a suspension state under the action of oxidation air; CaSO in desulfurized fly ash3The particle size and density of CaO, amphoteric oxide and heavy metal fine particles are small, the CaO, amphoteric oxide and heavy metal fine particles are in a suspension state above the air distribution disc 7-1 under the buoyancy action of oxidation air, and the pH value of the gypsum slurry subjected to two-stage oxidation is reduced to 4.5-6.0. The upper layer gypsum slurry which is deeply oxidized in the oxidation tower 7 contains a small amount of unreacted CaO, is sent to the gypsum slurry spraying layer 1-7 by the gypsum slurry spraying pump 9 for atomization, and continuously reacts with sulfur-containing flue gas, and simultaneously avoids the slurry in the desulfurization ash slurry spraying layer 1-6 due to higher pH in the desulfurization tower1, avoiding scaling phenomenon; amphoteric oxide and heavy metal particles in the gypsum slurry are discharged from a liquid outlet 7-2 on the side wall of the oxidation tower; the gypsum slurry after settlement and concentration is sent to a dehydration system by a gypsum discharge pump 10 for dehydration to prepare high-purity gypsum, and the gypsum dehydration filtrate is sent to a desulfurization and ashing slurry tank 3 by a pipeline. To prevent SO caused by too low pH during oxidation2And the top of the oxidation tower 7 is provided with an exhaust channel 7-3 communicated with the air inlet 1-1 of the desulfurizing tower 1 for feeding oxidized air which is oxidized into the desulfurizing tower 1.
e. And the clean flue gas after deep desulfurization is demisted by the secondary demister layers 1-8 and then discharged from the gas outlets 1-9 at the top of the desulfurizing tower 1, and finally the resource utilization of the semidry desulfurization ash is realized.
The retention time of the slurry in the oxidation tower 7 is 15-40 min.
The liquid-gas ratio of 1-6 of the desulfurization ash slurry spraying layer is 1-3L/Nm3The coverage rate of the spraying layer is 200-350%; the liquid-gas ratio of 1-7 of the gypsum slurry spraying layer is 2-5L/Nm3The coverage rate of the spraying layer is 150-250%.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, many changes and modifications can be made without departing from the inventive concept, and these changes and modifications all fall into the protection scope of the present invention.

Claims (7)

1. The utility model provides a wet flue gas desulfurization device of semi-dry desulfurization ash utilization, its characterized in that, includes desulfurization washing mechanism, desulfurization ash slurrying mechanism and oxidation concentration mechanism, wherein:
the desulfurization washing mechanism at least comprises a desulfurization tower (1), a desulfurization circulating pump (2), a desulfurization ash slurry spraying pump (6) and a gypsum slurry spraying pump (9), wherein the desulfurization tower (1) is provided with an air inlet (1-1) and an air outlet (1-9), and a desulfurization spraying layer (1-2), a primary demister layer (1-3), a liquid returning groove layer (1-4), a porous plate layer (1-5), a desulfurization ash slurry spraying layer (1-6), a gypsum slurry spraying layer (1-7) and a secondary demister layer (1-8) are sequentially arranged between the air inlet (1-1) and the air outlet (1-9) in the desulfurization tower (1) along the flowing direction of flue gas;
the desulfurization ash pulping mechanism at least comprises a desulfurization ash pulping tank (3), a desulfurization mortar liquid pump (4) and a desulfurization mortar liquid storage tank (5);
the oxidation concentration mechanism at least comprises an oxidation tower (7), an oxidation fan (8) and a gypsum discharge pump (10).
2. The wet desulfurization apparatus for resource utilization of semi-dry desulfurization ash according to claim 1, wherein the inlet of the desulfurization slurry pump (4) is connected to the bottom of the desulfurization ash slurry tank (3), the outlet thereof is connected to the top of the desulfurization slurry tank (5), the bottom of the desulfurization slurry tank (5) is connected to the desulfurization ash slurry spray layers (1-6) by a desulfurization ash slurry spray pump (6), the inlet of the gypsum slurry spray pump (9) is connected to the upper part of the oxidation tower (7), and the outlet of the gypsum slurry spray pump (9) is connected to the gypsum slurry spray layers (1-7).
3. The wet desulfurization apparatus for resource utilization of semi-dry desulfurized fly ash according to claim 1, wherein a gypsum filtrate pipe (3-1), a desulfurized fly ash delivery pipe (3-2) and a process water delivery pipe (3-3) are disposed above the desulfurized fly ash slurry tank (3), and stirring devices are disposed in the desulfurized fly ash slurry tank (3) and the desulfurized fly ash slurry storage tank (5).
4. The wet desulfurization apparatus for resource utilization of semidry desulfurization ash according to claim 1, the oxidation tower (7) is a sealing structure, an air distribution disc (7-1) is arranged in the tower body, a liquid outlet (7-2) and a liquid outlet communicated with the inlet of the gypsum slurry spray pump (9) are arranged on the side wall of the oxidation tower (7) above the air distribution disc (7-1), an air inlet (1-1) is arranged on the side wall of the oxidation tower (7) below the air distribution plate (7-1), the air inlet (1-1) is communicated with the outlet of the oxidation fan (8), the top of the oxidation tower (7) is provided with an exhaust passage (7-3) communicated with the air inlet (1-1) of the desulfurizing tower (1), the bottom of the oxidation tower (7) is communicated with the inlet of a gypsum discharge pump (10).
5. The wet desulfurization apparatus for resource utilization of semi-dry desulfurization ash according to claim 4, wherein the gas distribution plate (7-1) is a plate-like body provided with a plurality of openings, the openings have a pore diameter of 5mm to 20mm and an opening ratio of 30% to 50%, and the gas distribution plate (7-1) is located at a height of 1/3 to 1/2% of the oxidation tower (7).
6. The wet desulphurization device for resource utilization of semi-dry desulphurization ash according to claim 1, wherein the liquid return tank layer (1-4) is arranged above the first-stage demister layer (1-3), and the liquid return tank layer (1-4) is provided with a liquid discharge port which is communicated with the top of the oxidation tower (7) through a pipeline.
7. The wet desulfurization apparatus for resource utilization of semi-dry desulfurization ash according to claim 1, wherein the porous plate layer (1-5) comprises a plurality of layers of porous plates provided with openings (11), the diameter of the openings (11) is 10mm to 20mm, and the total area of the openings (11) is 15% to 40% of the cross-sectional area of the desulfurization tower (1).
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111747438A (en) * 2020-05-25 2020-10-09 沈阳环境科学研究院 pH regulation and control multistep stabilization modification method for dry/semi-dry desulfurized fly ash

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111747438A (en) * 2020-05-25 2020-10-09 沈阳环境科学研究院 pH regulation and control multistep stabilization modification method for dry/semi-dry desulfurized fly ash

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