Drying and calcining integrated equipment and process for producing semi-hydrated gypsum from desulfurized gypsum in power plant

Abstract

The invention belongs to the technical field of flue gas desulfurization gypsum recovery, and particularly relates to a drying and calcining integrated device and process for producing semi-hydrated gypsum from flue gas desulfurization gypsum in a power plant, the drying and calcining integrated device comprises a calcining device and a drying device, the drying device comprises a drying bin and a conveying belt arranged in the drying bin; a material block passes through the drying bin through rotation of the conveying belt and enters the calcining device, the drying bin is erected above the calcining device, a first conveying belt, a second conveying belt and a heat supply pipe are arranged in the drying bin, a material block forming device is arranged above the first conveying belt, and a material block forming device is arranged above the second conveying belt. The output end of the first conveying belt is connected with the input end of the second conveying belt, and the output end of the second conveying belt is connected with the input end of the calcining device. According to the flue gas desulfurization gypsum calcining device, the drying bin is arranged above the calcining device, flue gas desulfurization gypsum is dried by means of tail gas heat of the calcining device, the utilization rate of waste heat is effectively increased, the overall energy consumption of the device is reduced, and meanwhile the occupied area of the device is saved.

Description

Technical Field

[0001] This invention belongs to the field of desulfurized gypsum recycling technology, specifically relating to an integrated drying and calcination equipment and process for producing hemihydrate gypsum from desulfurized gypsum in power plants. Background Technology

[0002] The flue gas produced during the combustion of coal or oil in power plants contains a large amount of SO2. This type of gas is one of the main culprits in the formation of acid rain and the aggravation of air pollution. It not only causes serious damage to the ecological environment, but also harms human health. In order to meet emission standards, limestone is usually used as a desulfurizing agent to desulfurize SO2 in flue gas. The reaction between limestone and flue gas produces calcium sulfite, which is eventually formed into desulfurized gypsum after oxidation.

[0003] To ensure effective desulfurization, the desulfurizing agent in the desulfurization tower needs to be replaced promptly. The large quantities of desulfurized gypsum removed are bagged and stockpiled, occupying significant land resources and causing secondary environmental pollution. Desulfurized gypsum can be calcined to form hemihydrate gypsum for construction, thus turning waste into treasure. However, because the desulfurized gypsum has a high water content and is in a muddy state when removed from the desulfurization tower, direct calcination would result in significant fuel waste. Furthermore, if the lumpy desulfurized gypsum is dry on the outside but has a high internal water content, it is prone to cracking during calcination, generating loud noise and affecting the calcination quality. Therefore, drying is necessary before calcination. Currently, however, the calcination and drying equipment are set up separately, occupying a huge area, and each requires separate heating, resulting in enormous energy consumption. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an integrated drying and calcination equipment and process for producing hemihydrate gypsum from desulfurized gypsum in power plants, which reduces the equipment footprint and improves energy utilization.

[0005] The specific technical solution adopted in this invention is as follows: An integrated drying and calcination equipment for producing hemihydrate gypsum from desulfurized gypsum in power plants includes a calcination device and a drying device. The drying device includes a drying chamber and a conveyor belt installed inside the drying chamber. Material blocks pass through the drying chamber and enter the calcination device by means of the rotation of the conveyor belt. The drying chamber is erected above the calcination device. The drying chamber is equipped with a first conveyor belt, a second conveyor belt, and a heating pipe. A material block forming device is installed above the first conveyor belt. The output end of the first conveyor belt is connected to the input end of the second conveyor belt, and the output end of the second conveyor belt is connected to the input end of the calcination device.

[0006] The material block forming device includes a forming conveyor belt disposed above a first conveyor belt, a forming cover disposed on the forming conveyor belt, the forming cover forming a rectangular U-shaped frame and abutting against the surface of the first conveyor belt, a feeding pipe and a pressing plate disposed inside the forming conveyor belt, and the pressing plate having a lifting degree of freedom to move up and down relative to the forming cover by means of a lifting mechanism.

[0007] The forming conveyor belt has a left and right split structure. The forming cover includes two sets of L-shaped baffles arranged symmetrically at the center. The two sets of baffles are fastened together to form a U-shaped frame. The side of the baffle perpendicular to the forming conveyor belt is fixedly connected to the forming conveyor belt. The pressing plate is set between the split forming conveyor belts and is pressed into the interior of the forming cover by means of the pressing plate.

[0008] The pressing plate is provided with a rectangular array of breathable nails.

[0009] The heating pipe is also connected to a heat distribution box located below the first conveyor belt. The upper surface of the heat distribution box is provided with vent holes, and the belt surface of the first conveyor belt is provided with through holes. Multiple sets of heat distribution boxes are provided along the extension direction of the first conveyor belt.

[0010] The second conveyor belt is located below the first conveyor belt. The input end of the second conveyor belt is connected to the output end of the first conveyor belt via a first hopper. The output end of the second conveyor belt is connected to the input end of the calcining device via a second hopper. The end of the second hopper extends outside the drying chamber.

[0011] A bending rod is added to the side of the baffle parallel to the conveying direction of the first conveyor belt. The end of the bending rod is curved and gradually moves away from the side wall of the baffle. A slip ring is provided on the side wall of the baffle to form a sliding fit with the bending rod. The fixing points of the bending rod, the baffle, and the forming conveyor belt are staggered. A bending roller is provided above the first hopper of the forming conveyor belt.

[0012] The calcination device includes a heating chamber and a calcination tank installed inside the heating chamber. Roller supports are provided on both sides of the calcination tank. The two ends of the calcination tank have rotational freedom through the rollers on the roller supports. The rollers are connected to a drive motor. A conveying spiral blade is installed inside the calcination tank.

[0013] The exhaust end of the heating chamber is connected to the input end of the heating pipe.

[0014] A partition is provided between the first conveyor belt and the second conveyor belt, and the drying chamber is formed into an S-shaped air duct structure by means of the partition.

[0015] The beneficial effects of this invention are: This invention employs a drying chamber set above the calcination device, utilizing the heat from the exhaust gas of the calcination device to dry the desulfurized gypsum, effectively improving the utilization rate of waste heat, reducing the overall energy consumption of the equipment, and saving the equipment's floor space.

[0016] This invention utilizes the high plasticity of desulfurized gypsum to pre-form the raw material into blocks in the drying chamber. By pressing the air-permeable nails on the pressing plate, air holes are pressed into the blocks. With the help of the blowing of the heat-equalizing box, the blocks are dried quickly inside and out, thus improving the drying quality. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Part A is shown in the diagram; Figure 3 This is a schematic diagram of the structure of the molded cover from a top view. In the attached diagram, 1 is the drying chamber, 2 is the first conveyor belt, 3 is the second conveyor belt, 4 is the heating pipe, 5 is the forming conveyor belt, 6 is the forming cover, 601 is the baffle plate, 602 is the bending rod, 7 is the feeding pipe, 8 is the pressing plate, 9 is the heat settling box, 10 is the first discharge hopper, 11 is the second discharge hopper, 12 is the bending roller, 13 is the heating chamber, 14 is the calcining tank, and 15 is the partition plate. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Specific implementation examples Figure 1 As shown, this invention is an integrated drying and calcination equipment for producing hemihydrate gypsum from desulfurized gypsum in power plants. It includes a calcination device and a drying device. The drying device includes a drying chamber 1 and a conveyor belt installed inside the drying chamber 1. The material blocks pass through the drying chamber 1 and enter the calcination device by means of the rotation of the conveyor belt. The drying chamber 1 is erected above the calcination device. The drying chamber 1 is equipped with a first conveyor belt 2, a second conveyor belt 3, and a heating pipe 4. A material block forming device is installed above the first conveyor belt 2. The output end of the first conveyor belt 2 is connected to the input end of the second conveyor belt 3, and the output end of the second conveyor belt 3 is connected to the input end of the calcination device.

[0019] This invention utilizes a drying device located above the calcining apparatus. By employing the principle of rising hot air, the waste heat generated by the calcining apparatus can be reused in the drying stage. By setting up a first conveyor belt 2 and a second conveyor belt 3, the transport distance of the material blocks in the drying chamber 1 is increased, thereby increasing the drying time and helping to reduce the moisture content of the dried material blocks, laying the foundation for improving the calcination quality.

[0020] Furthermore, the present invention also includes a block forming device, which includes a forming conveyor belt 5 disposed above the first conveyor belt 2. A forming cover 6 is disposed on the forming conveyor belt 5. The forming cover 6 is formed into a rectangular U-shaped frame and abuts against the belt surface of the first conveyor belt 2. A feeding pipe 7 and a pressing plate 8 are disposed inside the forming conveyor belt 5. The pressing plate 8 has a lifting freedom relative to the forming cover 6 by means of a lifting mechanism.

[0021] like Figure 1 As shown, when the lumps forming device is working, the forming conveyor belt 5 and the first conveyor belt 2 operate synchronously and intermittently. When the forming conveyor belt 5 stops moving, the first conveyor belt 2 also stops moving. Then, the desulfurized gypsum slurry is poured into the forming hood 6 through the feeding pipe 7 that passes through the side wall of the drying chamber 1. The forming hood 6 forms the side wall, and the first conveyor belt 2 forms the bottom, so that a box-shaped space is formed inside the forming hood 6. The belt surface of the first conveyor belt 2 is a breathable mesh structure, which can support and filter moisture for the desulfurized gypsum. Then, the first conveyor belt 2 and the forming conveyor belt 5 move together to pour into the next forming hood 6.

[0022] Furthermore, such as Figure 3 As shown, the forming conveyor belt 5 has a split left and right structure. The forming cover 6 includes two sets of L-shaped baffles 601 arranged symmetrically at the center. The two sets of baffles 601 are fastened together to form a U-shaped frame. The sides of the baffles 601 perpendicular to the forming conveyor belt 5 are fixedly connected to the forming conveyor belt. The pressing plate 8 is placed between the split forming conveyor belts 5 and is pressed into the interior of the forming cover 6. The pressing plate 8 is provided with a rectangular array of venting nails. The pressing plate 8 compacts the slurry and inserts it into the block formed by the desulfurized gypsum through the venting nails. The venting nails are inserted to the bottom of the block, thereby forming a through-hole ventilation hole on the block.

[0023] Furthermore, such as Figure 1 and Figure 2 As shown, the heating pipe 4 is also connected to a heat distribution box 9 located below the first conveyor belt 2. The upper surface of the heat distribution box 9 is provided with vent holes, and the surface of the first conveyor belt 2 is provided with through holes. Multiple sets of heat distribution boxes 9 are arranged along the extending direction of the first conveyor belt 2. Figure 2 As shown, the high-temperature exhaust gas from the calcination device is drawn out through the heating pipe 4 and introduced into the hollow box-shaped heat equalization box 9. Then, through the through holes set on the surface of the first conveyor belt 2 and the ventilation structure of the mesh of the first conveyor belt 2 itself, the material block with ventilation holes is rapidly heated and blown, and quickly dried.

[0024] Furthermore, the second conveyor belt 3 is disposed below the first conveyor belt 2. The input end of the second conveyor belt 3 is connected to the output end of the first conveyor belt 2 via the first hopper 10, and the output end of the second conveyor belt 3 is connected to the input end of the calcining device via the second hopper 11. The end of the second hopper 11 extends outside the drying chamber 1.

[0025] like Figure 1 As shown, after initial drying and shaping, the material blocks on the first conveyor belt 2 move to the first hopper 10 at the end of the first conveyor belt 2 and are directed to the inner cavity of the first hopper 10. Under the influence of gravity, they fall onto the second conveyor belt 3. The falling distance is at least 1 meter, and it is preferable to break the material blocks with impact force, thereby further drying the material blocks. The end of the second conveyor belt 3 is connected to the input end of the calcining device via the second hopper 11. At the same time, the second hopper 11 forms a chimney effect, introducing hot air from the calcining device into the cavity of the second conveyor belt 3. Meanwhile, a partition 15 is provided between the first conveyor belt 2 and the second conveyor belt 3, and the drying chamber 1 is formed into an S-shaped air duct structure by means of the partition 15. This allows the broken material blocks to be further dried, and even if the material blocks are broken after being dried by the first conveyor belt 2, they can still maintain their block shape, leaving gaps for hot air to pass through, and allowing the newly exposed cross-sections to be further dried, thus improving the drying quality.

[0026] Furthermore, a bending rod 602 is added to the side of the baffle 601 parallel to the conveying direction of the first conveyor belt 2. The end of the bending rod 602 is curved and gradually moves away from the side wall of the baffle 601. A slip ring is provided on the side wall of the baffle 601 to form a sliding fit with the bending rod 602. The fixing points of the bending rod 602, the baffle 601 and the forming conveyor belt are staggered. A bending roller shaft 12 is provided above the first hopper 10 of the forming conveyor belt 5.

[0027] A bending roller 12 is installed at the end of the forming conveyor belt 5. The bending roller 12 causes the forming conveyor belt 5 to fold upwards. When the baffle 601 passes this point, due to the front-to-back difference between the baffle 601 and the bending rod 602 relative to the fixed position of the forming conveyor belt 5, the side of the baffle 601 and the bending rod 602 undergo relative displacement. Figure 3 As shown, the baffle 601 slides down relative to the lever 602, and the lower end of the lever 602 is bent into a J-shaped structure relative to the side wall of the baffle 601. The lever 602 pushes the side wall of the baffle 601 outward, so that the bonding surface between the side wall of the baffle 601 and the material block is forcibly pulled apart, so that the material block is removed from the forming cover 6 and falls smoothly.

[0028] Furthermore, the calcination apparatus includes a heating chamber 13 and a calcination tank 14 disposed within the heating chamber 13. Roller supports are provided on both sides of the calcination tank 14, and the two ends of the calcination tank 14 have rotational freedom via rollers on the roller supports. The rollers are connected to a drive motor, and a conveying spiral blade is disposed inside the calcination tank 14. The calcination tank 14 has a hollow tubular structure. With the help of the conveying spiral blade in conjunction with the rotation of the calcination tank 14, the fragments of the material can advance within the calcination tank 14 and further rub against each other to break them apart, thereby further improving the calcination effect.

[0029] Furthermore, the exhaust end of the heating chamber 13 is connected to the input end of the heating pipe 4, and a drying chamber exhaust pipe is provided at the top of the drying chamber at the starting end of the first conveyor belt 2. The heating chamber 13 is heated by a natural gas or coal gas burner, and the exhaust gas directly contacts the waste of desulfurized gypsum, which can further react the residual active ingredients in the desulfurized gypsum, and at the same time reduce the sulfur content in the exhaust gas, thereby reducing the pressure of subsequent exhaust gas treatment.

Claims

1. A drying and calcining integrated device for producing hemihydrate gypsum from power plant desulfurization gypsum, comprising a calcining device and a drying device, the drying device comprising a drying bin (1) and a conveying belt arranged in the drying bin (1), the material block passing through the drying bin (1) by means of the rotation of the conveying belt and entering the calcining device, characterized in that: The drying bin (1) is arranged above the calcining device, the first conveying belt (2), the second conveying belt (3) and the heating pipe (4) are arranged in the drying bin (1), the briquette forming device is arranged above the first conveying belt (2), the output end of the first conveying belt (2) is connected with the input end of the second conveying belt (3), and the output end of the second conveying belt (3) is connected with the input end of the calcining device. ​ 2. The drying and calcining integrated apparatus for producing hemihydrate gypsum from the power plant desulfurization gypsum according to claim 1, characterized in that: The briquette forming device comprises the forming conveying belt (5) arranged above the first conveying belt (2), the forming cover (6) is arranged on the forming conveying belt (5), the forming cover (6) surrounds the rectangular H-shaped frame and abuts against the belt surface of the first conveying belt (2), the inside of the forming conveying belt (5) is provided with the feeding pipe (7) and the pressing plate (8), and the pressing plate (8) has the lifting freedom of moving up and down relative to the forming cover (6) by means of the lifting mechanism.

3. The drying and calcining integrated apparatus for producing hemihydrate gypsum from the power plant desulfurization gypsum according to claim 2, characterized in that: The forming conveying belt (5) is a left-right split structure, the forming cover (6) comprises two groups of center-symmetrically arranged L-shaped baffle plates (601), the two groups of baffle plates (601) are buckled to form the H-shaped frame, the side of the baffle plate (601) perpendicular to the forming conveying belt (5) is fixedly connected with the forming conveying belt, the pressing plate (8) is arranged between the split forming conveying belts (5) and is pressed into the inside of the forming cover (6) by means of the pressing plate (8).

4. The drying and calcining integrated apparatus for producing hemihydrate gypsum from the power plant desulfurization gypsum according to claim 2, characterized in that: The pressing plate (8) is provided with the air-permeable nails arranged in a rectangular array.

5. The drying and calcining integrated apparatus for producing hemihydrate gypsum from the power plant desulfurization gypsum according to claim 1, characterized in that: The heating pipe (4) is further connected with the heat equalizing box (9) arranged below the first conveying belt (2), the upper surface of the heat equalizing box (9) is provided with air-permeable holes, the belt surface of the first conveying belt (2) is provided with through holes, and the heat equalizing box (9) is provided with a plurality of groups along the extension direction of the first conveying belt (2).

6. The drying and calcining integrated apparatus for producing hemihydrate gypsum from power plant desulfurization gypsum according to claim 3, characterized in that: The second conveying belt (3) is arranged below the first conveying belt (2), the input end of the second conveying belt (3) is connected with the output end of the first conveying belt (2) by means of the first material falling hopper (10), the output end of the second conveying belt (3) is connected with the input end of the calcining device by means of the second material falling hopper (11), and the tail end of the second material falling hopper (11) extends out of the drying bin (1).

7. The integrated drying and calcining facility for the production of hemihydrate gypsum from power plant desulfurization gypsum according to claim 6, characterized in that: The baffle plate (601) is additionally provided with the bending rod (602) on the side parallel to the conveying direction of the first conveying belt (2), the tail end of the bending rod (602) is curved and gradually away from the side wall of the baffle plate (601), the side wall of the baffle plate (601) is provided with the sliding ring in sliding fit with the bending rod (602), the bending rod (602) and the baffle plate (601) are arranged in a staggered mode in front of and behind the fixing point of the forming conveying belt, and the forming conveying belt (5) is provided with the bending roller (12) above the first material falling hopper (10).

8. The drying and calcining integrated apparatus for producing hemihydrate gypsum from the power plant desulfurization gypsum according to claim 1, characterized in that: The calcining device comprises a heating bin (13) and a calcining tank (14) arranged in the heating bin (13), both sides of the calcining tank (14) are provided with roller shaft supports, both ends of the calcining tank (14) have rotary freedom degrees by means of the roller shafts on the roller shaft supports, the roller shafts are connected with driving motors, and the calcining tank (14) is provided with conveying spiral blades.

9. The drying and calcining integrated apparatus for producing hemihydrate gypsum from the power plant desulfurization gypsum according to claim 8, characterized in that: An exhaust end of the heating bin (13) is communicated with an input end of the heat supply pipe (4).

10. The drying and calcining integrated apparatus for producing hemihydrate gypsum from power plant desulfurization gypsum according to claim 1, characterized by: A partition plate (15) is arranged between the first conveying belt (2) and the second conveying belt (3), and the drying bin (1) is separated into an S-shaped air duct structure by the partition plate (15).

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