Sodium sulfate drying tail gas treatment device

Abstract

The utility model provides a sodium sulfate drying tail gas treatment device. The sodium sulfate drying tail gas treatment device comprises a dryer, a cyclone separator and an alkaline washing tower which are connected in sequence, a top tail gas outlet of the dryer is communicated with an inlet of the cyclone separator through the negative pressure fan, a top exhaust pipe of the cyclone separator is communicated with a gas inlet in the lower part of the alkaline washing tower, and a purified gas outlet is formed in the top of the alkaline washing tower; a sodium sulfate collecting tank is arranged at the bottom of the dryer; and an ash hopper at the bottom of the cyclone separator is communicated with the sodium sulfate collecting tank. The sodium sulfate drying tail gas is purified, and waste of sodium sulfate is remarkably reduced.

Description

Technical Field

[0001] This application relates to the field of sodium sulfate tail gas treatment technology, and in particular to a sodium sulfate drying tail gas treatment device. Background Technology

[0002] Sodium sulfate is a salt formed by the combination of sulfate and sodium ions, with the chemical formula Na₂SO₄. It is soluble in water and glycerol but insoluble in ethanol. High-purity, fine-particle anhydrous sodium sulfate is called Glauber's salt (sodium sulfate decahydrate), which is hygroscopic. It appears as colorless, transparent, large crystals or small granular crystals. Sodium sulfate readily absorbs moisture when exposed to air, forming sodium sulfate decahydrate, also known as mirabilite, which is slightly alkaline. Sodium sulfate is mainly used in the manufacture of water glass, glass, porcelain enamel, pulp, refrigeration mixtures, detergents, desiccants, dye diluents, analytical chemical reagents, pharmaceuticals, and animal feed.

[0003] In the preparation of sodium sulfate, the sodium sulfate-containing slurry obtained after the reaction is first evaporated, crystallized, and centrifuged to prepare crude sodium sulfate. The crude product has a high water content and requires further drying.

[0004] During the drying process of crude sodium sulfate, exhaust gas is generated, which contains water vapor, a small amount of acidic gas, and a small amount of sodium sulfate powder. If the exhaust gas is discharged directly without treatment, the emission of acidic gas will cause air pollution and waste sodium sulfate. Utility Model Content

[0005] This application provides a sodium sulfate drying tail gas treatment device to solve the problems mentioned in the background art.

[0006] This application provides a sodium sulfate drying tail gas treatment device, comprising: a dryer, a cyclone separator and an alkali washing tower connected in sequence;

[0007] The top exhaust outlet of the dryer is connected to the inlet of the cyclone separator via a negative pressure fan. The top exhaust pipe of the cyclone separator is connected to the air inlet at the bottom of the alkaline washing tower. The top of the alkaline washing tower is equipped with a purified gas outlet.

[0008] The bottom of the dryer is equipped with a sodium sulfate collection tank, and the ash hopper at the bottom of the cyclone separator is connected to the sodium sulfate collection tank.

[0009] Optionally, the alkali washing tower is equipped with a spray unit, which includes an alkali pump, a spray pipe and an atomizing nozzle. The alkali pump is installed on the spray pipe, one end of the spray pipe is connected to the bottom of the alkali washing tower, and the other end of the spray pipe is connected to the atomizing nozzle. The atomizing nozzle is installed in the upper part of the alkali washing tower.

[0010] Optionally, the cyclone separator is equipped with a scraping assembly, which includes a motor, a first rotating shaft, a first bevel gear, a second bevel gear, a second rotating shaft, a connecting rod, and a scraper.

[0011] The output end of the motor is fixedly connected to one end of the first rotating shaft, and the other end of the first rotating shaft is fixedly connected to the first bevel gear. The first bevel gear and the second bevel gear are perpendicularly meshed. The second bevel gear is fixedly connected to the second rotating shaft. A connecting rod is connected to the end of the second rotating shaft away from the second bevel gear. Scrapers are fixedly connected to both ends of the connecting rod. The outer side of the scraper is in contact with the inside of the cyclone separator.

[0012] Optionally, the scraper assembly is also provided with reinforcing ribs, with both ends of the reinforcing ribs being fixedly connected to the scrapers on both sides.

[0013] Optionally, the outer sides of the first bevel gear and the second bevel gear are covered with a cover;

[0014] The first and second rotating shafts are dynamically sealed to the cover via bearings.

[0015] Optionally, the cyclone separator is provided with a jacket, with a heat exchange medium inlet at the bottom of the jacket and a heat exchange medium outlet at the top of the jacket.

[0016] Optionally, a filter screen is installed on the top exhaust pipe of the cyclone separator near the inlet end.

[0017] The sodium sulfate drying tail gas treatment device provided in this application achieves purification of sodium sulfate drying tail gas, and has the following advantages compared with the prior art:

[0018] (1) The sodium sulfate drying tail gas is first separated into gas and solid phases by a cyclone separator to recover the sodium sulfate powder mixed in the drying tail gas, thus avoiding the waste of sodium sulfate. At the same time, the tail gas discharged from the cyclone separator is fed into an alkaline scrubbing tower. The tail gas moves from bottom to top in the alkaline scrubbing tower, while alkaline solution is sprayed from top to bottom. The acidic gas in the tail gas reacts with the alkaline solution to form salt. Meanwhile, some of the water vapor in the tail gas is cooled and becomes liquid water, which falls to the bottom of the alkaline scrubbing tower with the alkaline solution, thus removing the acidic gas in the drying tail gas. The remaining tail gas continues to rise and is discharged from the top of the alkaline scrubbing tower. This application not only achieves the purification treatment of sodium sulfate drying tail gas, but also recovers the sodium sulfate powder mixed in the tail gas, which has good environmental and economic benefits.

[0019] (2) By installing a scraping assembly in the cyclone separator, a small amount of sodium sulfate adhering to the inner wall of the cyclone separator is scraped off when the dry tail gas is separated into gas and solid, thus avoiding the waste of sodium sulfate and facilitating the long-term operation of the cyclone separator.

[0020] (3) A heat exchange medium (such as steam, hot water, heat transfer oil, etc.) is introduced into the jacket through the heat exchange medium inlet, and the heat exchange medium is output from the heat exchange medium outlet. This setting can continue to dry the dry tail gas entering the cyclone separator, prevent the tail gas temperature from dropping in the cyclone separator, causing the water vapor in the tail gas to condense, and then causing the sodium sulfate mixed in the tail gas to absorb water and adhere to the inner wall of the cyclone separator. The jacket setting avoids the tail gas from cooling down in the cyclone separator, improves the recovery efficiency of sodium sulfate, and at the same time improves the dryness of the sodium sulfate powder recovered in the ash hopper. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a sodium sulfate drying tail gas treatment device provided in an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the structure of a cyclone separator provided in one embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the structure of a cyclone separator provided in another embodiment of this application;

[0025] Explanation of reference numerals in the attached figures:

[0026] 1: Dryer; 2: Cyclone separator; 3: Alkali washing tower; 4: Sodium sulfate collection tank; 6: Cover; 7: Jacket; 110: Negative pressure fan; 201: Ash hopper; 202: Filter screen; 210: Motor; 220: First rotating shaft; 230: First bevel gear; 240: Second bevel gear; 250: Second rotating shaft; 260: Connecting rod; 270: Scraper; 280: Reinforcing rib; 301: Purified gas outlet; 310: Alkali pump; 320: Spray pipe; 330: Atomizing nozzle; 710: Heat exchange medium inlet; 720: Heat exchange medium outlet. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0028] like Figure 1 As shown, this application provides a sodium sulfate drying tail gas treatment device, comprising: a dryer 1, a cyclone separator 2, and an alkali washing tower 3 connected in sequence;

[0029] The top exhaust outlet of dryer 1 is connected to the inlet of cyclone separator 2 through negative pressure fan 110. The top exhaust pipe of cyclone separator 2 is connected to the air inlet at the bottom of alkaline washing tower 3. Alkaline washing tower 3 is provided with a purified gas outlet 301 at the top.

[0030] A sodium sulfate collection tank 4 is provided at the bottom of the dryer 1, and the ash hopper 201 at the bottom of the cyclone separator 2 is connected to the sodium sulfate collection tank 4.

[0031] Specifically, crude sodium sulfate is dried in dryer 1. The exhaust gas generated during the drying process contains water vapor, a small amount of acidic gases (SO2, H2SO4 mist), and a small amount of sodium sulfate powder. Under the negative pressure suction of negative pressure fan 110, the drying exhaust gas enters cyclone separator 2 from the top exhaust gas outlet of dryer 1. The drying exhaust gas enters from the tangential inlet at the top of the cylinder of cyclone separator 2 and rotates along the inner wall of the cylinder. The solid sodium sulfate powder, which has a large inertial centrifugal force, is thrown to the outer layer due to centrifugal force, while the airflow flows in the inner layer, thus achieving gas-solid separation. As the radius of rotation decreases in the conical part, the tangential velocity increases accordingly, causing the airflow and solid sodium sulfate powder to undergo a downward spiral motion. When the airflow reaches the vicinity of the bottom of the cone, it turns into an upward rotating motion and is eventually discharged from the top exhaust pipe of the cyclone separator 2. Meanwhile, the solid sodium sulfate powder falls into the ash hopper 201 along the inner wall, and the sodium sulfate powder in the ash hopper 201 is transported back to the sodium sulfate collection tank 4, thus avoiding the waste of sodium sulfate.

[0032] Simultaneously, the exhaust gas discharged from the top exhaust pipe of the cyclone separator 2 enters the alkaline washing tower 3 through the air inlet at the bottom. The exhaust gas moves from bottom to top within the alkaline washing tower 3, while alkaline solution is sprayed from top to bottom. Mass transfer occurs between the exhaust gas and the alkaline solution within the alkaline washing tower 3. Acidic gases in the exhaust gas react with the alkaline solution to form salts. Simultaneously, some water vapor in the exhaust gas cools and becomes liquid water, falling with the alkaline solution to the bottom of the alkaline washing tower 3, thus removing acidic gases from the dried exhaust gas. The remaining exhaust gas continues to rise and is discharged through the purified gas outlet 301 at the top of the alkaline washing tower 3, achieving the purification treatment of the sodium sulfate drying exhaust gas. After treatment by the cyclone separator 2 and alkaline washing tower 3, the exhaust gas discharged will not pollute the surrounding air or environment, demonstrating excellent environmental benefits.

[0033] The alkaline solution is selected from at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, and waste alkaline solution generated in the factory. The concentration of the alkaline solution is determined according to the actual working conditions and is not limited here.

[0034] This application achieves the purification of sodium sulfate drying tail gas through the above-described scheme. The sodium sulfate drying tail gas is first subjected to gas-solid separation via a cyclone separator, recovering the sodium sulfate powder entrained in the tail gas and avoiding waste. Simultaneously, the tail gas discharged from the cyclone separator is fed into an alkaline scrubbing tower. The tail gas moves from bottom to top in the alkaline scrubbing tower, while alkaline solution is sprayed from top to bottom. The acidic gases in the tail gas react with the alkaline solution to form salts. At the same time, some of the water vapor in the tail gas cools down to liquefy water and falls to the bottom of the alkaline scrubbing tower with the alkaline solution, thus removing the acidic gases from the drying tail gas. The remaining tail gas continues to rise and is discharged from the top of the alkaline scrubbing tower. This application not only purifies the sodium sulfate drying tail gas but also recovers the sodium sulfate powder entrained in the tail gas, resulting in significant environmental and economic benefits.

[0035] Optionally, the alkali washing tower 3 is equipped with a spray unit, which includes an alkali pump 310, a spray pipe 320 and an atomizing nozzle 330. The alkali pump 310 is installed on the spray pipe 320. One end of the spray pipe 320 is connected to the bottom of the alkali washing tower 3, and the other end of the spray pipe 320 is connected to the atomizing nozzle 330. The atomizing nozzle 330 is installed in the upper part of the interior of the alkali washing tower 3.

[0036] Specifically, the alkali solution is located in the bottom of the alkali washing tower 3. By turning on the alkali solution pump 310, the alkali solution in the bottom of the tower is transported to the atomizing nozzle 330 through the spray pipe 320 and sprayed out. The sprayed atomized alkali solution has a small particle size, which can help the alkali solution react with the acidic gas to obtain salt and water, which fall into the bottom of the alkali washing tower 3 along with the alkali solution. At the same time, the alkali solution is circulated and sprayed by the alkali solution pump 310 to achieve the treatment of acidic gas.

[0037] When the pH value of the alkaline solution in the column is less than or equal to the preset value, the alkaline solution is extracted and re-introduced into the column.

[0038] like Figure 2 As shown, optionally, the cyclone separator 2 is provided with a scraping assembly, which includes a motor 210, a first rotating shaft 220, a first bevel gear 230, a second bevel gear 240, a second rotating shaft 250, a connecting rod 260, and a scraper 270.

[0039] The output end of the motor 210 is fixedly connected to one end of the first rotating shaft 220, and the other end of the first rotating shaft 220 is fixedly connected to the first bevel gear 230. The first bevel gear 230 is perpendicularly meshed with the second bevel gear 240. The second bevel gear 240 is fixedly connected to the second rotating shaft 250. A connecting rod 260 is connected to the end of the second rotating shaft 250 away from the second bevel gear 240. Scrapers 270 are fixedly connected to both ends of the connecting rod 260. The outer side of the scraper 270 is in contact with the inside of the cyclone separator 2.

[0040] Specifically, the cyclone separator 2 is equipped with a scraping assembly, which is used to scrape off the small amount of sodium sulfate adhering to the inner wall of the cyclone separator 2 when performing gas-solid separation of the dried exhaust gas, thus avoiding the waste of sodium sulfate and facilitating the long-term operation of the cyclone separator 2.

[0041] The motor 210 is fixed to the plate or ground. Turning on the motor 210 provides power, driving the first rotating shaft 220 to rotate. The first rotating shaft 220 drives the first bevel gear 230 to rotate, which in turn drives the second bevel gear 240 meshing with it to rotate, thereby driving the second rotating shaft 250 to rotate. The end of the second rotating shaft 250 is fixedly connected to the center of the connecting rod 260. When the second rotating shaft 250 rotates, it drives the connecting rod 260 to rotate, which in turn drives the scraper 270 to rotate. The outer side of the scraper 270 contacts the inside of the cyclone separator 2. During rotation, it scrapes off the sodium sulfate powder adhering to the inner wall of the cyclone separator 2, which then falls into the ash hopper 201.

[0042] The first bevel gear 230 and the second bevel gear 240 are located below the ash hopper 201, and the connection between the second rotating shaft 250 and the ash hopper 201 is made by a rotating seal.

[0043] like Figure 2 As shown, optionally, the scraper assembly is also provided with reinforcing ribs 280, and the two ends of the reinforcing ribs 280 are fixedly connected to the scrapers 270 on both sides respectively.

[0044] Specifically, the installation of the reinforcing rib 280 helps improve the stability of the scraper 270 during rotation, which in turn helps the cyclone separator 2 to operate for a long period of time.

[0045] like Figure 2 As shown, optionally, the outer sides of the first bevel gear 230 and the second bevel gear 240 are covered by a cover 6;

[0046] The first rotating shaft 220 and the second rotating shaft 250 are dynamically sealed to the cover 6 via bearings.

[0047] Specifically, the cover 6 is used to protect the first bevel gear 230 and the second bevel gear 240. At the same time, the first rotating shaft 220 and the second rotating shaft 250 are dynamically sealed to the cover 6 through bearings, which is beneficial to the stable operation of the device. Meanwhile, the cover 6 is fixed to the plate or the ground, and during the operation of the device, the first rotating shaft 220 and the second rotating shaft 250 rotate relative to the cover 6.

[0048] like Figure 3 As shown, optionally, the cyclone separator 2 is provided with a jacket 7 on the outside, with a heat exchange medium inlet 710 at the lower part of the jacket 7 and a heat exchange medium outlet 720 at the upper part of the jacket 7.

[0049] Specifically, a heat exchange medium (such as steam, hot water, or heat transfer oil) is introduced into the jacket 7 through the heat exchange medium inlet 710, and the heat exchange medium is output from the heat exchange medium outlet 720. This arrangement allows for continued drying of the dry tail gas entering the cyclone separator 2, preventing the tail gas from cooling down upon entering the cyclone separator 2, which would cause the water vapor in the tail gas to condense and cause the sodium sulfate mixed in the tail gas to absorb water and adhere to the inner wall of the cyclone separator 2. The jacket 7 prevents the tail gas from cooling down and, together with the scraper assembly, improves the recovery efficiency of sodium sulfate, while also improving the dryness of the sodium sulfate powder recovered in the ash hopper 201.

[0050] like Figure 3 As shown, optionally, a filter screen 202 is provided at the top exhaust pipe of the cyclone separator 2 near the inlet end.

[0051] Specifically, the exhaust gas discharged from the top exhaust pipe of the cyclone separator 2 is further filtered through the filter screen 202 to avoid the waste of sodium sulfate powder and at the same time reduce the working load of the alkali washing tower 3.

[0052] The technical solution of this application will be illustrated in detail below with specific embodiments.

[0053] The operating procedure of the sodium sulfate drying tail gas treatment device in this embodiment is as follows:

[0054] The crude sodium sulfate is dried in dryer 1. The exhaust gas generated during the drying process contains water vapor, a small amount of acidic gases (SO2, H2SO4 mist), and a small amount of sodium sulfate powder. Under the negative pressure suction of the negative pressure fan 110, the drying exhaust gas enters the cyclone separator 2 from the top exhaust outlet of dryer 1. The drying exhaust gas enters tangentially from the upper part of the cylinder of the cyclone separator 2 and rotates along the inner wall of the cylinder. The solid sodium sulfate powder, with its large inertial centrifugal force, is thrown to the outer layer due to centrifugal force, while the airflow flows in the inner layer, thus achieving gas-solid separation. As the radius of rotation decreases in the conical part, the tangential velocity increases accordingly, causing the airflow and solid sodium sulfate powder to undergo a downward spiral motion. When it reaches near the bottom of the cone, the airflow turns into an upward rotating motion and is finally discharged from the top exhaust pipe of the cyclone separator 2, while the solid sodium sulfate powder falls along the inner wall into the ash hopper 201, and the sodium sulfate powder in the ash hopper 201 is transported back to the sodium sulfate collection tank 4.

[0055] The exhaust gas from the top exhaust pipe of the cyclone separator 2 enters the alkaline washing tower 3 through the air inlet at the bottom. The exhaust gas moves upwards within the alkaline washing tower 3. Simultaneously, by activating the alkaline solution pump 310, the alkaline solution in the tower bottom is pumped through the spray pipe 320 to the atomizing nozzle 330 and sprayed downwards. The acidic gas in the exhaust gas reacts with the alkaline solution to form salt. Simultaneously, some of the water vapor in the exhaust gas cools down to form liquid water, which falls with the alkaline solution to the bottom of the alkaline washing tower 3. The remaining exhaust gas continues to rise, is filtered through the filter screen 202, and is discharged through the purified gas outlet 301 at the top of the alkaline washing tower 3, thus achieving purification of the sodium sulfate drying exhaust gas. When the pH value of the alkaline solution in the tower bottom is less than or equal to a preset value (e.g., pH 7), the alkaline solution is extracted and re-introduced into the tower bottom.

[0056] During operation, the motor 210 provides power, driving the first rotating shaft 220 to rotate. The first rotating shaft 220 drives the first bevel gear 230 to rotate, which in turn drives the meshing second bevel gear 240 to rotate, thereby driving the second rotating shaft 250 to rotate. The end of the second rotating shaft 250 is fixedly connected to the center of the connecting rod 260. When the second rotating shaft 250 rotates, it drives the connecting rod 260 to rotate, which in turn drives the scraper 270 to rotate. The outer side of the scraper 270 is in contact with the inside of the cyclone separator 2. During rotation, it scrapes off the sodium sulfate powder adhering to the inner wall of the cyclone separator 2, which falls into the ash hopper 201. A heat exchange medium (such as steam, hot water, heat transfer oil, etc.) is introduced into the jacket 7 through the heat exchange medium inlet 710, and the heat exchange medium is output from the heat exchange medium outlet 720. This arrangement allows for continued drying of the dry exhaust gas entering the cyclone separator 2.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A sodium sulfate drying tail gas treatment device, characterized in that, include: The dryer (1), cyclone separator (2) and alkali washing tower (3) are connected in sequence. The top exhaust outlet of the dryer (1) is connected to the inlet of the cyclone separator (2) through a negative pressure fan (110). The top exhaust pipe of the cyclone separator (2) is connected to the air inlet at the bottom of the alkaline washing tower (3). The alkaline washing tower (3) is provided with a purified gas outlet (301) at the top. The dryer (1) is provided with a sodium sulfate collection tank (4) at the bottom, and the ash hopper (201) at the bottom of the cyclone separator (2) is connected to the sodium sulfate collection tank (4).

2. The sodium sulfate drying tail gas treatment device according to claim 1, characterized in that, The alkaline washing tower (3) is equipped with a spray unit, which includes an alkaline pump (310), a spray pipe (320) and an atomizing nozzle (330). The alkaline pump (310) is mounted on the spray pipe (320). One end of the spray pipe (320) is connected to the bottom of the alkaline washing tower (3), and the other end of the spray pipe (320) is connected to the atomizing nozzle (330). The atomizing nozzle (330) is located in the upper part of the alkaline washing tower (3).

3. The sodium sulfate drying tail gas treatment device according to claim 1, characterized in that, The cyclone separator (2) is equipped with a scraping assembly, which includes a motor (210), a first rotating shaft (220), a first bevel gear (230), a second bevel gear (240), a second rotating shaft (250), a connecting rod (260), and a scraper (270). The output end of the motor (210) is fixedly connected to one end of the first rotating shaft (220), the other end of the first rotating shaft (220) is fixedly connected to the first bevel gear (230), the first bevel gear (230) is perpendicularly meshed with the second bevel gear (240), the second bevel gear (240) is fixedly connected to the second rotating shaft (250), the end of the second rotating shaft (250) away from the second bevel gear (240) is connected to the connecting rod (260), the two ends of the connecting rod (260) are respectively fixedly connected to the scraper (270), and the outer side of the scraper (270) is in contact with the inside of the cyclone separator (2).

4. The sodium sulfate drying tail gas treatment device according to claim 3, characterized in that, The scraper assembly is also provided with reinforcing ribs (280), and the two ends of the reinforcing ribs (280) are fixedly connected to the scrapers (270) on both sides respectively.

5. The sodium sulfate drying tail gas treatment device according to claim 4, characterized in that, The outer sides of the first bevel gear (230) and the second bevel gear (240) are covered by a cover (6); The first rotating shaft (220) and the second rotating shaft (250) are dynamically sealed to the cover (6) through bearings.

6. The sodium sulfate drying tail gas treatment device according to claim 1, characterized in that, The cyclone separator (2) is provided with a jacket (7) on the outside. The jacket (7) has a heat exchange medium inlet (710) at the bottom and a heat exchange medium outlet (720) at the top.

7. The sodium sulfate drying tail gas treatment device according to any one of claims 1-6, characterized in that, A filter screen (202) is provided at the top exhaust pipe of the cyclone separator (2) near the inlet end.

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