Calcium chloride flue gas desulfurization circulating system

Abstract

The utility model discloses a calcium chloride flue gas desulfurization circulating system, which relates to the technical field of flue gas desulfurization, and comprises a desulfurization tower, a slurry delivery pump, a gypsum filter, a dissolving tank and a corresponding delivery pipeline, one end of the desulfurization tower is connected with the dissolving tank through the delivery pipeline, and the dissolving tank is used for dissolving calcium chloride and process water to obtain a calcium chloride solution; the other end of the desulfurization tower is connected with the gypsum filter through a slurry conveying pump, the desulfurization tower is used for performing double decomposition reaction on sulfur dioxide in the flue gas and a calcium chloride solution to generate calcium sulfite precipitate, and calcium sulfite is further oxidized to obtain calcium sulfate gypsum. By adopting the system disclosed by the utility model, the desulfurization efficiency is effectively improved, the purity of gypsum generated after desulfurization is improved, meanwhile, the production of hydrochloric acid is increased, a system integrating multiple production processes is formed, flue gas desulfurization is effectively realized by using calcium chloride, and the calcium chloride can be used for continuous circulating processing.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas desulfurization, in particular to a calcium chloride flue gas desulfurization circulation system. Background Art

[0002] At present, boiler flue gas systems are divided into dry, semi-dry and wet methods according to the form of desulfurizers. Dry and semi-dry methods have the characteristics of low investment and low energy consumption, but their desulfurization efficiency is not higher than 90%; wet desulfurization can achieve a desulfurization efficiency of more than 95%. According to the properties of the desulfurizer, it can be divided into gypsum method, ammonia method, double alkali method, magnesium method, organic ammonia method, etc.

[0003] The gypsum processing system is commonly used at present. The desulfurization gypsum product produced by limestone desulfurization contains a large amount of calcium carbonate and impurities. It cannot be reused in other fields and needs to occupy land for storage, causing secondary pollution. The desulfurization reaction involves a three-phase reaction of gas, liquid and solid, and the calcium carbonate produced by sulfidation is not easily soluble in water, and the mass transfer efficiency is low, which reduces the desulfurization efficiency. The limestone needs to be ground into tiny particles below 300 mesh for reaction. The grinding step is relatively cumbersome, time-consuming and labor-intensive. In addition, when the limestone undergoes desulfurization reaction, CaCO3, CaSO3 and CaSO4 will be produced, causing scarring and blockage in the reaction system, affecting the reaction efficiency.

[0004] Hydrochloric acid can be used in the metallurgical and chemical industries and is widely used, generally using independent production processes or equipment.

[0005] A system for simultaneously desulfurizing flue gas and producing gypsum. The applicant previously used perphosphate rock to combine with phosphoric acid to form a calcium-containing acid solution that was circulated back to the desulfurization tower for desulfurization circulation. The application numbers are 2024103745043, a method for producing phosphate concentrate and co-producing gypsum by desulfurizing phosphate rock flue gas and its circulation system, 202410374565X, a method for co-producing phosphoric acid and gypsum by desulfurizing phosphate rock flue gas based on dilute phosphoric acid and its circulation system, and 2024103748554, a method for producing iron concentrate and co-producing phosphoric acid based on ferrous sulfate and its system. At present, there is no system that integrates the production of hydrochloric acid and gypsum by calcium chloride flue gas desulfurization. After continuous research and development, a calcium chloride flue gas desulfurization circulation system has been formed, which is also a production system for calcium chloride flue gas desulfurization to produce hydrochloric acid and co-produce gypsum. Utility Model Content

[0006] The utility model provides a calcium chloride flue gas desulfurization circulation system, which solves the existing problems.

[0007] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a calcium chloride flue gas desulfurization circulation system, comprising a desulfurization tower, a slurry delivery pump, a gypsum filter, a dissolving tank and corresponding delivery pipelines, one end of the desulfurization tower is connected to the dissolving tank through a delivery pipeline, the dissolving tank is used to dissolve calcium chloride and process water to obtain a calcium chloride solution, the other end of the desulfurization tower is connected to the gypsum filter through a slurry delivery pump, the desulfurization tower is used to carry out a double decomposition reaction between sulfur dioxide in the flue gas and the calcium chloride solution to generate a calcium sulfite precipitate, and the calcium sulfite is further oxidized to obtain calcium sulfate gypsum.

[0008] Preferably, the dissolving tank includes a dissolving tank, a feed port, a discharge port, a driving motor, a stirring shaft, stirring blades and a spraying mechanism. The upper surface of the dissolving tank is provided with a feed port, the lower surface of the dissolving tank is provided with a discharge port, the upper surface of the dissolving tank is provided with a driving motor, the output shaft of the driving motor is connected to the stirring shaft, the stirring shaft is provided with a plurality of stirring blades, and the dissolving tank is provided with a spraying mechanism.

[0009] Preferably, the spray mechanism includes a connecting rod, a water outlet pipe, a water inlet pipe, a spray pipe, a water pump and a spray head. The dissolving tank is symmetrically provided with connecting rods, one end of the connecting rod is connected to the water outlet pipe, and one end of the connecting rod is connected to the spray pipe. The spray pipe is ring-shaped, and a plurality of spray heads are provided below the spray pipe. One end of the water pump is connected to the water outlet pipe, and the other end of the water pump is connected to the water inlet pipe.

[0010] Preferably, a mounting frame is provided on one side of the dissolving tank, and a water pump is provided on the mounting frame.

[0011] Preferably, a support column is provided at the bottom of the dissolving tank.

[0012] Preferably, a sealing cover is provided on the feed port.

[0013] Preferably, a filter screen is provided on the inner wall of one end of the discharge port, and a valve is provided on the discharge port.

[0014] Preferably, electric push rods are symmetrically provided on both sides of the bottom end of the stirring shaft, and scrapers are provided on the electric push rods.

[0015] Preferably, one end of the water inlet pipe is connected to external process water.

[0016] Preferably, the conveying pipeline has a bending section.

[0017] The beneficial effects of the utility model are:

[0018] The system can realize the use of calcium chloride solution produced by the dissolution of calcium chloride and water as a desulfurizing agent, and by oxidizing, precipitating and separating the calcium sulfite obtained after the reaction, liquid hydrochloric acid and solid gypsum are separated, the impurity content of the gypsum is reduced, and the calcium in the calcium chloride is used for desulfurization to obtain high-purity gypsum, so that the high-purity gypsum can be recycled for secondary utilization, and the recovered hydrochloric acid can also be used in other industries, without the need to build a hydrochloric acid device for processing, reducing the cost of hydrochloric acid production, and obtaining cheap hydrochloric acid resources. The use of this system effectively improves the desulfurization efficiency and the purity of the gypsum produced after desulfurization, and at the same time increases the production of hydrochloric acid, forming a system that integrates multiple production processes, and effectively realizes flue gas desulfurization with calcium chloride and can be used for continuous cycle processing.

[0019] The dissolving tank of this system can deliver the raw material calcium chloride into the dissolving tank through the feed port. One end of the water inlet pipe is connected with the external process water. The water pump works to drive the process water to flow into the spray pipe, and then spray out from the spray head. The drive motor works to drive the stirring blades on the stirring shaft to rotate, accelerate the dissolution, and improve the work efficiency. At the same time, the electric push rod is extended to make the scraper contact with the inner wall of the dissolving tank, scrape off the raw materials remaining on the inner wall, make the stirring reaction more complete, improve the production efficiency when the dissolving tank is used, and realize the production of calcium chloride solution and then return it to the desulfurization tower for desulfurization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram of the calcium chloride desulfurization system for producing hydrochloric acid and co-producing gypsum.

[0021] Figure 2 This is a schematic diagram of the dissolving tank structure of the utility model.

[0022] Figure 3 It is a schematic diagram of the cross-sectional structure of the dissolving tank of the utility model.

[0023] Figure 4 for Figure 3 Schematic diagram of the enlarged structure at point A in the middle.

[0024] Numbers in the figure: 1. Desulfurization tower; 2. Slurry delivery pump; 3. Gypsum filter; 4. Dissolution tank; 5. Delivery pipeline; 6. Dissolution tank; 7. Feed inlet; 8. Discharge outlet; 9. Drive motor; 10. Stirring shaft; 11. Stirring blades; 12. Spraying mechanism; 13. Connecting rod; 14. Water outlet pipe; 15. Water inlet pipe; 16. Spraying pipe; 17. Spraying head; 18. Cover; 19. Valve; 20. Mounting frame; 21. Water pump; 22. Support column; 23. Filter; 24. Electric push rod; 25. Scraper. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0026] Reference Figure 1-Figure 4 As shown, a calcium chloride flue gas desulfurization circulation system includes a desulfurization tower 1, a slurry delivery pump 2, a gypsum filter 3, a dissolving tank 4 and a corresponding delivery pipeline 5. One end of the desulfurization tower 1 is connected to the dissolving tank 4 through the delivery pipeline 5. The dissolving tank 4 is used to dissolve calcium chloride and process water to obtain a calcium chloride solution. The other end of the desulfurization tower 1 is connected to the gypsum filter 3 through the slurry delivery pump 2. The desulfurization tower 1 is used to carry out a double decomposition reaction between sulfur dioxide in the flue gas and the calcium chloride solution to generate calcium sulfite precipitate, and the calcium sulfite is further oxidized to obtain calcium sulfate gypsum.

[0027] The dissolving tank 4 includes a dissolving tank 6, a feed port 7, a discharge port 8, a driving motor 9, a stirring shaft 10, stirring blades 11 and a spraying mechanism 12. The upper surface of the dissolving tank 6 is provided with a feed port 7, the lower surface of the dissolving tank 6 is provided with a discharge port 8, the upper surface of the dissolving tank 6 is provided with a driving motor 9, the output shaft of the driving motor 9 is connected to the stirring shaft 10, and a plurality of stirring blades 11 are provided on the stirring shaft 10. The dissolving tank 6 is provided with a spraying mechanism 12. When the driving motor 9 works, the stirring blades 11 on the stirring shaft 10 are driven to rotate, thereby accelerating the dissolution and improving the production efficiency of the dissolving tank 4 when it is used.

[0028] The spray mechanism 12 includes a connecting rod 13, a water outlet pipe 14, a water inlet pipe 15, a spray pipe 16, a water pump 21 and a spray head 17. The connecting rod 13 is symmetrically arranged in the dissolving tank 6, one end of the connecting rod 13 is connected to the water outlet pipe 14, and one end of the connecting rod 13 is connected to the spray pipe 16. The spray pipe 16 is ring-shaped, and a plurality of spray heads 17 are arranged below the spray pipe 16. One end of the water pump 21 is connected to the water outlet pipe 14, and the other end of the water pump 21 is connected to the water inlet pipe 15. When the water pump 21 works, it drives the process water to flow into the spray pipe 16, so that it is sprayed out from the spray head 17, so that the reaction and stirring with the raw materials are more comprehensive.

[0029] A mounting frame 20 is provided on one side of the dissolving tank 6, and a water pump 21 is provided on the mounting frame 20. A supporting column 22 is provided at the bottom of the dissolving tank 6 to play a supporting role. A sealing cover 18 is provided on the feed port 7, and a filter screen 23 is provided on the inner wall of one end of the discharge port 8 to filter the calcium chloride solution. A valve 19 is provided on the discharge port 8. Electric push rods 24 are symmetrically provided on both sides of the bottom end of the stirring shaft 10, and a scraper 25 is provided on the electric push rods 24 to make the stirring reaction more sufficient. One end of the water inlet pipe 15 is connected to the external process water, and the conveying pipeline 5 has a bending section.

[0030] The structural working principle of the dissolving tank 4 is as follows: when in use, the raw material calcium chloride is first fed into the dissolving tank 6 through the feed port 7, one end of the water inlet pipe 15 is connected to the external process water, the water pump 21 works, drives the process water to flow into the spray pipe 16, and then sprays out from the spray head 17, the driving motor 9 works, drives the stirring blade 11 on the stirring shaft 10 to rotate, accelerates the dissolution, and improves the working efficiency, and at the same time the electric push rod 24 extends, so that the scraper 25 contacts the inner wall of the dissolving tank 6, scrapes off the raw materials remaining on the inner wall, makes the stirring reaction more sufficient, and improves the production efficiency of the dissolving tank 4 when in use;

[0031] The working principle of the overall system is as follows: raw material calcium chloride and process water enter the dissolution tank 4, in which calcium chloride and process water are dissolved to obtain calcium chloride solution, and the calcium chloride solution enters the desulfurization tower 1;

[0032] In the desulfurization tower 1, sulfur dioxide in the flue gas undergoes a double decomposition reaction with the calcium chloride solution to generate calcium sulfite precipitation, which is further oxidized to obtain calcium sulfate (gypsum). The calcium sulfate slurry is transported to the gypsum filter 3 through the slurry pump 2;

[0033] The filter cake produced by the filter is a calcium sulfate (gypsum) product, and the filtrate is hydrochloric acid, which is mined and sold as a product.

[0034] The use of the above system can also refer to the following reaction steps:

[0035] S1, calcium chloride and process water are introduced into a dissolution tank 4 according to a certain ratio, and calcium chloride and process water are dissolved and reacted in the dissolution tank 4 to obtain a calcium chloride solution, and the calcium chloride solution enters the desulfurization tower 1;

[0036] S2, input sulfur-containing flue gas into the desulfurization tower 1, sulfur dioxide in the flue gas and calcium chloride solution undergo double decomposition reaction in the desulfurization tower 1 to generate calcium sulfite precipitate, and the calcium sulfite further undergoes oxidation reaction to obtain calcium sulfate slurry, and the calcium sulfate slurry is transported to the gypsum filter 3 through a slurry pump;

[0037] S3, filter to separate the calcium sulfate slurry into solid and liquid, the solid after the solid-liquid separation of the calcium sulfate slurry is calcium sulfate, that is, gypsum, and the filtrate after separation is hydrochloric acid;

[0038] The above three steps form a continuous and repeated process of desulfurization and filtration to achieve the desulfurization of calcium chloride to produce hydrochloric acid and co-produce gypsum.

[0039] In the step S1, the calcium chloride is calcium chloride dihydrate or anhydrous calcium chloride, the calcium chloride reacts with process water for 1 hour, the reaction temperature is room temperature, and the concentration of the calcium chloride solution obtained after the reaction is 25%-45%.

[0040] In the step S2, the temperature of the sulfur-containing flue gas is 130° C.-150° C., and the liquid-gas ratio is 1:1000.

[0041] The calcium chloride solution and sulfur dioxide in the sulfur-containing flue gas adopt double decomposition reaction. The calcium chloride and sulfur dioxide react in the presence of water to generate calcium sulfite precipitation. The main reaction formula is:

[0042] CaCl2+SO2+H2O→CaSO3+2HCl;

[0043] Calcium sulfite is oxidized into calcium sulfate precipitate, i.e. gypsum, by oxidation reaction. The main reaction formula is:

[0044] 2CaSO3+O2→2CaSO4.

[0045] The above system is also a production system for calcium chloride flue gas desulfurization to produce hydrochloric acid and co-produce gypsum, a hydrochloric acid production system based on calcium chloride, and a gypsum production system based on calcium chloride.

[0046] The process water in the above description refers to the tap water generally used.

[0047] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A calcium chloride flue gas desulfurization circulation system, comprising a desulfurization tower (1), a slurry delivery pump (2), a gypsum filter (3), a dissolution tank (4) and corresponding delivery pipelines (5), characterized in that: One end of the desulfurization tower (1) is connected to a dissolving tank (4) via a delivery pipeline (5), and the dissolving tank (4) is used to dissolve calcium chloride and process water to obtain a calcium chloride solution. The other end of the desulfurization tower (1) is connected to a gypsum filter (3) via a slurry delivery pump (2), and the desulfurization tower (1) is used to cause sulfur dioxide in the flue gas to undergo a double decomposition reaction with the calcium chloride solution to generate a calcium sulfite precipitate, and the calcium sulfite is further oxidized to obtain calcium sulfate gypsum.

2. A calcium chloride flue gas desulfurization circulation system according to claim 1, characterized in that, The dissolving tank (4) comprises a dissolving tank (6), a feed port (7), a discharge port (8), a driving motor (9), a stirring shaft (10), stirring blades (11) and a spray mechanism (12); the upper surface of the dissolving tank (6) is provided with a feed port (7); the lower surface of the dissolving tank (6) is provided with a discharge port (8); the upper surface of the dissolving tank (6) is provided with a driving motor (9); the output shaft of the driving motor (9) is connected to the stirring shaft (10); a plurality of stirring blades (11) are provided on the stirring shaft (10); and the inside of the dissolving tank (6) is provided with a spray mechanism (12).

3. A calcium chloride flue gas desulfurization circulation system according to claim 2, characterized in that, The spray mechanism (12) comprises a connecting rod (13), a water outlet pipe (14), a water inlet pipe (15), a spray pipe (16), a water pump (21) and a spray head (17). The dissolving tank (6) is symmetrically provided with a connecting rod (13), one end of the connecting rod (13) is connected to the water outlet pipe (14), one end of the connecting rod (13) is connected to the spray pipe (16), the spray pipe (16) is in a ring shape, and a plurality of spray heads (17) are provided below the spray pipe (16). One end of the water pump (21) is connected to the water outlet pipe (14), and the other end of the water pump (21) is connected to the water inlet pipe (15).

4. A calcium chloride flue gas desulfurization circulation system according to claim 2, characterized in that, A mounting frame (20) is provided on one side of the dissolving tank (6), and a water pump (21) is provided on the mounting frame (20).

5. A calcium chloride flue gas desulfurization circulation system according to claim 4, characterized in that, A support column (22) is provided at the bottom of the dissolving tank (6).

6. A calcium chloride flue gas desulfurization circulation system according to claim 2, characterized in that, The feed port (7) is provided with a sealing cover (18).

7. A calcium chloride flue gas desulfurization circulation system according to claim 2, characterized in that: A filter screen (23) is provided on the inner wall of one end of the discharge port (8), and a valve (19) is provided on the discharge port (8).

8. A calcium chloride flue gas desulfurization circulation system according to claim 2, characterized in that: Electric push rods (24) are symmetrically arranged on both sides of the bottom end of the stirring shaft (10), and a scraper (25) is arranged on the electric push rods (24).

9. A calcium chloride flue gas desulfurization circulation system according to claim 3, characterized in that: One end of the water inlet pipe (15) is connected to external process water.

10. A calcium chloride flue gas desulfurization circulation system according to claim 1, characterized in that: The conveying pipe (5) has a bent section.

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