System and method for co-producing beta gypsum through microwave type slurry and foam integrated treatment

Abstract

The invention discloses a microwave type slurry and foam integrated treatment and beta gypsum co-production system which comprises an integrated equipment body, and the interior of the integrated equipment body is longitudinally divided into a separation chamber and a drying chamber by a separation baffle; ventilation openings are formed in the middle-upper parts of the separation baffles; a feeding pipe is arranged at the top of the separation chamber, a filter screen is obliquely arranged in the middle of the separation chamber, and a circulating air pipe is further arranged on the side wall of the separation chamber; an oxidation air pipe is further arranged at the middle lower part of the separation chamber and is connected with an oxidation air pipe network, and a stirrer is further arranged in the lower part of the separation chamber; a drying magnetron is arranged in the top of the drying chamber, a wave-absorbing bed layer is further arranged in the middle lower part of the drying chamber, and a discharge hopper is arranged below the wave-absorbing bed layer. The invention discloses a method for co-producing beta gypsum through microwave type slurry and foam integrated treatment. The system provided by the invention can solve the problems of slurry bubbling and insufficient oxidation, and can remove the COD of the slurry to a certain extent to prepare beta gypsum with high added value.

Description

Technical Field

[0001] The present invention belongs to the technical field of wet desulfurization, and in particular relates to a system for microwave-type slurry-foam integrated treatment of co-produced beta gypsum, and also relates to a method for microwave-type slurry-foam integrated treatment of co-produced beta gypsum. Background Art

[0002] As desulfurization system operating conditions change, slurry foaming, insufficient oxidation, and deteriorating slurry quality have become frequent problems, hindering the stable operation of desulfurization systems. If left untreated, they can easily lead to unplanned unit shutdowns and environmental pollution. Desulfurization slurry is a solid-liquid mixture. The solid phase primarily consists of calcium sulfate, calcium carbonate, calcium sulfite, and acid-insoluble matter, while the liquid phase primarily consists of soluble salts and some organic matter. The solids content is generally 5%-20%, and the average solid particle size is tens of microns. Currently, slurry foaming in wet desulfurization is primarily addressed by adding polyether and silicone oil defoamers. However, with the addition of defoamers, the defoaming effect weakens or even becomes ineffective. Furthermore, the accumulation of COD causes absorbent shielding and increases slurry viscosity, resulting in deteriorating slurry quality and reduced absorption efficiency, leading to environmental violations. To improve slurry oxidation in desulfurization systems, coal-fired power plants generally increase the oxidation air volume, requiring the slurry oxidation system to operate at full capacity under all operating conditions. This approach not only has limited effectiveness but also increases unnecessary energy consumption.

[0003] In response to the difficulties of the desulfurization system, it is urgent to develop an integrated desulfurization slurry treatment facility to fundamentally eliminate the effects of slurry foaming and insufficient oxidation, thereby ensuring the safe, stable and efficient operation of the desulfurization system. Summary of the Invention

[0004] The object of the present invention is to provide a microwave-type slurry foam integrated treatment and co-production of beta gypsum system, which can produce beta gypsum while treating the slurry without causing secondary pollution.

[0005] Another object of the present invention is to provide a method for microwave-type slurry foam integrated treatment and co-production of beta gypsum.

[0006] The technical solution adopted by the present invention is a system for integrated microwave slurry foam treatment and co-production of beta gypsum, including an integrated equipment body, the interior of the integrated equipment body is longitudinally divided into a separation chamber and a drying chamber by a separation baffle; a vent is provided in the middle and upper part of the separation baffle; a feed pipe is provided at the top of the separation chamber, a filter screen is provided at an angle in the middle of the separation chamber, the filter screen is located below the feed pipe, and a circulating air duct is also provided on the side wall of the separation chamber, the circulating air duct is located below the filter screen; the circulating air duct corresponds to the vent on the separation baffle; an oxidation air duct is also provided in the middle and lower part of the separation chamber, one end of the oxidation air duct is connected to the oxidation air duct network, and the other end of the oxidation air duct extends out of the inner wall of the separation chamber; an agitator is also provided in the lower part of the separation chamber; a drying magnetron is provided in the top of the drying chamber, an absorbing bed layer is also provided in the middle and lower part of the drying chamber, and a discharge hopper is provided below the absorbing bed layer.

[0007] The present invention is also characterized in that: The absorbing bed layer comprises a supporting frame which is fixed in the drying chamber and filled with microwave absorbing material.

[0008] A discharge valve is provided at the bottom of the discharge hopper, and a silo door is also provided below the drying chamber.

[0009] A slurry buffer tank is vertically arranged between the separation chamber and the lower part of the drying chamber. The slurry buffer tank is located on one side of the separation baffle. The height of the slurry buffer tank is higher than the absorbing bed layer. A buffer tank discharge pipe is arranged at the bottom of the slurry buffer tank.

[0010] An exhaust pipe is provided on the outer wall of the top of the drying chamber, a flushing water tank is provided on the inner wall of the drying chamber, an absorbing bed flushing water pipe is provided on the flushing water tank, and a plurality of nozzles are provided on the absorbing bed flushing water pipe.

[0011] A feed regulating valve is provided on the feed pipe.

[0012] A plurality of pool bottom magnetrons are also arranged at the bottom of the separation chamber, and a water-proof cover is provided on the outside of the pool bottom magnetrons.

[0013] A pool bottom discharge pipe is also provided outside the bottom of the separation chamber; a liquid level gauge is provided inside the top of the separation chamber. The oxidation air duct network includes several vertical branches parallel to each other, and the several vertical branches are connected by several horizontal branches; the oxidation air duct is connected to the horizontal branches, and a microbubble generator is provided at the connection between the vertical branch and the horizontal branch; an oxidation air duct network flushing water pipe is provided on the oxidation air duct, and the oxidation air duct network flushing water pipe is located outside the separation chamber.

[0014] Another technical solution adopted by the present invention is a method for integrated microwave slurry foam treatment and co-production of beta gypsum, which is specifically implemented according to the following steps: Step 1: The desulfurized slurry enters the separation chamber from the feed pipe, passes through the filter screen, and the foam is directly intercepted by the filter screen and blown to the drying chamber through the circulating air duct; Step 2: The desulfurized slurry after step 1 is stirred by an agitator in a separation chamber, and the oxidation air enters the oxidation air duct network through the oxidation air duct, is transformed into microbubbles by a microbubble generator and enters the desulfurized slurry. The microwaves emitted by the magnetron at the bottom of the pool pass through the water-proof cover and are conducted into the slurry. Under the cavitation action of shear force and microwaves, nano-scale microbubbles are formed; Step 3: The foam from the separation chamber falls on the absorbing bed layer, where it is dehydrated and dried to form β-gypsum. The absorbing bed layer absorbs the microwaves emitted by the drying magnetron, and the β-gypsum falls into the discharge hopper. Part of the water vapor generated by the foam drying rises with the air flow to the exhaust pipe and is discharged from the exhaust pipe, while the other part condenses on the wall and is collected in the flushing water tank as flushing water.

[0015] The beneficial effects of the present invention are: 1. Utilize the density difference between foam and slurry and the size of foam to continuously separate the foam from the overflow slurry; 2. Through microwave heating, the absorbing bed is heated in a direction, which reduces heating energy consumption and also increases the foam drying temperature to >150-200°C. While the organic matter in the foam is decomposed by heat, the gypsum slurry is dehydrated and dried to produce high-value-added beta gypsum. 3. The catalytic effect of the Fe²⁺ / Mn²⁺-loaded catalyst, the cavitation and free radical effects of microwave aeration technology, and the bubble dispersion effect of microbubble technology work together to increase the liquid phase dissolved oxygen from 5-10 mg / L in traditional aeration to 15-30 mg / L. This not only removes COD from the slurry, but also deeply oxidizes the sulfite in the slurry into calcium sulfate. 4. It can permanently eliminate the foam in the foam slurry without causing secondary pollution.

[0016] 5. The separation efficiency of foam is improved by utilizing the surface enrichment of organic matter such as surfactants and the floating effect of bubbles.

[0017] 6. A buffer tank is set up for the slurry to prevent a large amount of slurry from flowing into the foam drying chamber; 7. The positive pressure of the oxidizing air is used for natural circulation to achieve the blowing and separation of foam, without the need for external power equipment, which is energy-saving and highly efficient; 8. Collect condensed water for washing the absorbing bed, which saves water. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of a system for integrated microwave slurry foam treatment and co-production of beta gypsum.

[0019] In the figure, 1. feed pipe; 2. feed regulating valve; 3. integrated equipment body; 4. filter; 5. circulating air duct; 6. oxidation air duct network flushing water pipe; 7. oxidation air duct; 8. oxidation air duct network; 9. pool bottom slurry discharge pipe; 10. microbubble generator; 11. pool bottom magnetron; 12. water shield; 13. agitator; 14. buffer tank slurry discharge pipe; 15. slurry buffer tank; 16. silo door; 17. discharge valve; 18. discharge hopper; 19. absorbing bed; 20. absorbing bed flushing water pipe; 21 flushing water tank; 22. exhaust pipe; 23. drying magnetron; 24. separation baffle; 25. level gauge. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 The microwave slurry foam integrated treatment system for co-production of beta gypsum of the present invention is as follows: Figure 1 As shown, it includes an integrated equipment body 3, which is divided into two layers, the outer layer can be made of but not limited to stainless steel, alloy steel and other materials to provide strength for the body, and the inner layer must be made of non-wave-absorbing, anti-corrosion and temperature-resistant materials, including but not limited to reinforced polypropylene, PTFE and the like.

[0022] The interior of the integrated equipment body 3 is longitudinally divided into a separation chamber and a drying chamber by a separation baffle 24; a ventilation hole is provided in the upper middle part of the separation baffle 24; the function of the separation baffle 14 is to physically isolate the separation chamber and the drying chamber to prevent foam from splashing and contaminating the drying magnetron 23, and it uses corrosion-resistant and wear-resistant materials with certain mechanical strength, including but not limited to PTFE, fiberglass and other materials.

[0023] A feed pipe 1 is provided at the top of the separation chamber, a feed regulating valve 2 is provided on the feed pipe 1, a filter screen 4 is provided obliquely in the middle of the separation chamber, the filter screen 4 is located below the feed pipe 1, the flow area of ​​the filter screen 4 accounts for 20% to 80% of its surface area, the pore diameter is between 1-5 mm, and the inclination angle with the horizontal plane is between 5°-30°, so as to ensure the effective separation of slurry and foam.

[0024] The side wall of the separation chamber is also provided with a circulation air duct 5, which is located below the filter screen 4. The circulation air duct 5 corresponds to the vent on the separation baffle 24. Most of the original foam is directly intercepted by the filter screen 4, and a small amount of the original foam and the newly generated foam in the slurry are accumulated in the foam layer on the top of the slurry layer. After being swept by the circulation air duct 5, they are blown to the drying chamber through the vent. An agitator 13 is also provided in the lower part of the separation chamber, the main function of which is to prevent the slurry from settling. The agitator type is mainly axial flow type, including but not limited to propeller agitator.

[0025] Example 2 Furthermore, several bottom magnetrons 11 are located at the bottom of the separation chamber. These magnetrons 11 are encased in water-repellent covers 12. Microwaves emitted by these magnetrons 11 pass through these covers and are conducted into the slurry. These covers are made of wave-transmitting materials, including but not limited to aluminum oxide, quartz glass, and organic polymers. These covers prevent the magnetrons 11 from coming into direct contact with water, while also transmitting the microwave energy into the slurry without absorbing it. A bottom slurry discharge pipe 9 is also provided outside the bottom of the separation chamber. The function of the bottom slurry discharge pipe 9 is to discharge the treated slurry into the desulfurization system pit. The pit slurry returns to the absorption tower slurry pool to achieve slurry renewal.

[0026] An oxidation air duct 7 is further provided in the middle and lower part of the separation chamber. One end of the oxidation air duct 7 is connected to the oxidation air duct network 8, and the other end of the oxidation air duct 7 extends out of the inner wall of the separation chamber; an oxidation air duct network flushing water pipe 6 is provided on the oxidation air duct 7, and the oxidation air duct network flushing water pipe 6 is located outside the separation chamber; The oxidation air duct network 8 is fixed in the separation chamber by a support frame. It comprises several parallel vertical branches, connected by several horizontal branches. The vertical and horizontal branches form a grid-like oxidation air duct network 8. The oxidation air duct 7 is connected to the horizontal branches, and a microbubble generator 10 is installed at the junction of the vertical and horizontal branches. The oxidation air enters the oxidation air duct network 8 below the slurry layer through the oxidation air duct 7. The microbubble generator 10 is transformed into microbubbles with a size of 1μm-1mm before entering the slurry. Under the cavitation effects of shear force and microwaves, nano-scale microbubbles with a size of less than 1μm are ultimately formed, increasing the gas-liquid contact area. The horizontal and vertical branches are made of metal pipes loaded with Fe²⁺ / Mn²⁺ catalysts, which catalyze the oxidation of sulfites and organic matter in the slurry. This ultimately achieves deep oxidation of sulfites and partial removal of COD. The microbubble generator 10 can be disc-type or tubular.

[0027] Example 3 Furthermore, a level gauge 25 is provided in the top of the separation chamber. The function of the level gauge 25 is to monitor the liquid level of the slurry layer. It is recommended to use a level gauge that is resistant to foam interference, preferably a radio frequency admittance level gauge or a guided wave radar level gauge.

[0028] Example 4 Furthermore, a drying magnetron 23 is provided in the top of the drying chamber, an exhaust pipe 22 is provided on the outer wall of the top of the drying chamber, a flushing water tank 21 is provided on the inner wall of the drying chamber, an absorbing bed flushing water pipe 20 is provided on the flushing water tank 21, and a plurality of nozzles are provided on the absorbing bed flushing water pipe 20; An absorbing bed layer 19 is also provided in the middle and lower part of the drying chamber. The absorbing bed layer 19 includes a support frame fixed in the drying chamber and filled with microwave absorbing material. A discharge hopper 18 is provided below the absorbing bed layer 19. A discharge valve 17 is provided at the bottom of the discharge hopper 18. A silo door 16 is also provided below the drying chamber. The foam from the separation chamber falls onto the absorbing bed 19, where it dehydrates and dries, producing beta-gypsum. The absorbing bed 19 absorbs microwaves emitted by the drying magnetron 23, maintaining a temperature between 120°C and 200°C during operation. The beta-gypsum falls directly into the discharge hopper 18, where it is controlled by the discharge valve 17 and then into the silo. A silo door 16 is provided for easy maintenance and unclogging. A portion of the water vapor generated by the drying foam rises with the airflow to the exhaust pipe 22, where it is discharged. The remaining portion condenses against the wall and is collected in the flushing water tank 21 for use as flushing water. The absorbing bed flushing water pipe 20 is connected to the flushing water tank 21 for regular flushing of the absorbing bed.

[0029] Example 5 Furthermore, a slurry buffer tank 15 is vertically arranged between the separation chamber and the lower part of the drying chamber. The slurry buffer tank 15 is located on one side of the separation baffle 24. The height of the slurry buffer tank 15 is higher than the absorbing bed layer 19. A buffer tank discharge pipe 14 is provided at the bottom of the slurry buffer tank 15. The function of the slurry buffer tank 15 is to prevent the slurry from flowing directly into the drying chamber and play a buffering role. A buffer tank discharge pipe 14 is also provided at the bottom to discharge the slurry in the buffer tank into the pit.

[0030] The present invention improves the gas-liquid mass transfer efficiency by coupling microbubble technology, microwave oxygenation technology and metal catalytic oxidation technology, and can remove a portion of COD while improving the oxidation efficiency of the foaming slurry; uses mechanical design and circulating air purge to achieve self-separation of the foaming slurry; and uses microwave heating to heat the bed layer to achieve foam drying and prepare high-value-added beta gypsum.

[0031] Example 6 The method of the present invention for the integrated microwave slurry foam treatment of co-produced beta gypsum is specifically implemented according to the following steps: Step 1: The desulfurized slurry enters the separation chamber from the feed pipe 1. After passing through the filter screen 4, most of the foam is directly intercepted by the filter screen 4. A small amount of foam and newly generated foam in the slurry gather in the foam layer on the top of the slurry layer and are blown to the drying chamber through the circulating air duct 5. Step 2: The desulfurized slurry after step 1 is stirred by the stirrer 13 in the separation chamber, and the oxidation air enters the oxidation air duct network 8 through the oxidation air duct 7 and is transformed into microbubbles by the microbubble generator 10 and enters the desulfurized slurry. The microwaves emitted by the magnetron 11 at the bottom of the pool pass through the water-proof cover 12 and are conducted into the slurry. Under the cavitation action of shear force and microwaves, nano-scale microbubbles with a size of less than 1 μm are finally formed. The oxidation air duct network 8 has a catalytic oxidation effect on sulfites and organic matter in the slurry, thereby achieving deep oxidation of sulfites and partial removal of COD. Step 3: The foam from the separation chamber falls onto the absorbing bed layer 19, where it is dehydrated and dried to produce β-gypsum. The absorbing bed layer 19 absorbs the microwaves emitted by the drying magnetron 23, maintaining a temperature between 120°C and 200°C during operation. The β-gypsum falls directly into the discharge hopper 18. Part of the water vapor generated by the foam drying rises with the air flow to the exhaust pipe 22 and is discharged from the exhaust pipe 22. The other part condenses on the wall and is collected in the flushing water tank 21 as flushing water.

[0032] The system and method of the present invention for integrated microwave slurry foam treatment and co-production of beta gypsum can solve the problems of slurry foaming and insufficient oxidation, while removing slurry COD to a certain extent and preparing a high-value-added solid product of beta gypsum, thereby being energy-saving, efficient, green and clean.

Claims

1. A microwave-type slurry foam integrated treatment system for co-production of beta gypsum, characterized in that: The invention comprises an integrated equipment body (3), wherein the interior of the integrated equipment body (3) is longitudinally divided into a separation chamber and a drying chamber by a separation baffle (24); a vent is provided in the middle and upper part of the separation baffle (24); a feed pipe (1) is provided on the top of the separation chamber, a filter screen (4) is provided obliquely in the middle of the separation chamber, and the filter screen (4) is located below the feed pipe (1); a circulating air duct (5) is further provided on the side wall of the separation chamber, and the circulating air duct (5) is located below the filter screen (4); the circulating air duct ( 5) corresponds to the vent on the separation baffle (24); an oxidation air duct (7) is further provided in the middle and lower part of the separation chamber, one end of the oxidation air duct (7) is connected to the oxidation air duct network (8), and the other end of the oxidation air duct (7) extends out of the inner wall of the separation chamber; an agitator (13) is further provided in the lower part of the separation chamber; a drying magnetron (23) is provided in the top of the drying chamber, an absorbing bed layer (19) is further provided in the middle and lower part of the drying chamber, and a discharge hopper (18) is provided below the absorbing bed layer (19).

2. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: The absorbing bed layer (19) comprises a supporting frame, the supporting frame is fixed in the drying chamber, and the supporting frame is filled with microwave absorbing material.

3. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: A discharge valve (17) is provided at the bottom of the discharge hopper (18), and a silo door (16) is also provided below the drying chamber.

4. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: A slurry buffer tank (15) is also vertically arranged between the separation chamber and the lower part of the drying chamber. The slurry buffer tank (15) is located on one side of the separation baffle 24. The height of the slurry buffer tank (15) is higher than the absorbing bed layer (19). A buffer tank discharge pipe (14) is arranged at the bottom of the slurry buffer tank (15).

5. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: An exhaust pipe (22) is provided on the top outer wall of the drying chamber, a flushing water tank (21) is provided on the inner wall of the drying chamber, an absorbing bed flushing water pipe (20) is provided on the flushing water tank (21), and a plurality of nozzles are provided on the absorbing bed flushing water pipe (20).

6. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: The feed pipe (1) is provided with a feed regulating valve (2).

7. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: A plurality of pool bottom magnetrons (11) are also provided at the bottom of the separation chamber, and a water-proof cover (12) is provided on the outside of the pool bottom magnetrons (11).

8. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: A pool bottom discharge pipe (9) is also provided outside the bottom of the separation chamber; and a liquid level gauge (25) is provided inside the top of the separation chamber.

9. The microwave-type slurry-foam integrated treatment and co-production of beta gypsum system according to claim 1, characterized in that: The oxidation air duct network (8) comprises a plurality of mutually parallel vertical branches, which are connected by a plurality of horizontal branches; the oxidation air duct (7) is connected to the horizontal branches, and a microbubble generator (10) is provided at the connection between the vertical branch and the horizontal branch; an oxidation air duct network flushing water pipe (6) is provided on the oxidation air duct (7), and the oxidation air duct network flushing water pipe (6) is located outside the separation chamber.

10. A method for integrated microwave slurry foam treatment and co-production of beta gypsum, characterized in that: Please follow the steps below to implement it: Step 1: The desulfurized slurry enters the separation chamber from the feed pipe (1), passes through the filter (4), and the foam is directly intercepted by the filter (4) and blown to the drying chamber through the circulating air duct (5); Step 2: The desulfurized slurry after step 1 is stirred by a stirrer (13) in a separation chamber, and the oxidation air enters the oxidation air duct network 8 through the oxidation air duct (7), is transformed into microbubbles by the microbubble generator (10), and enters the desulfurized slurry. The microwaves emitted by the magnetron (11) at the bottom of the pool pass through the water-proof cover (12) and are conducted into the slurry. Under the cavitation action of shear force and microwaves, nano-scale microbubbles are formed. Step 3: The foam from the separation chamber falls on the absorbing bed layer (19), where it is dehydrated and dried to generate beta gypsum. The absorbing bed layer (19) absorbs the microwaves emitted by the drying magnetron (23), and the beta gypsum falls into the discharge hopper (18). A portion of the water vapor generated by the foam drying rises with the air flow to the exhaust pipe (22) and is discharged from the exhaust pipe (22), while the other portion condenses on the wall and is collected in the flushing water tank (21) as flushing water.

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