Flue gas desulfurization gypsum drying device

Abstract

The utility model relates to a flue gas desulfurization gypsum drying device which comprises a fluidized bed drying device, the fluidized bed drying device comprises a shell, an air distribution plate is arranged in the shell, an air bellow is arranged on the lower side of the air distribution plate, a dilute-phase area and a dense-phase area are arranged in a cavity of the shell on the upper side of the air distribution plate, and the dilute-phase area is arranged on the upper side of the dense-phase area; and a cyclone separator is also arranged in the fluidized bed drying device and is arranged at the tail part of the fluidized bed drying device. The device has the advantages that high-temperature particles are adopted as a heat source and have huge temperature difference with flue gas desulfurization gypsum wet materials, direct mixing contact type heat exchange is achieved, and the heat exchange effect is good. The two particles are particles of dozens of micrometers to hundreds of micrometers and have huge specific surface area, under the fluidization effect, the contact area of the two particles is far larger than that of a traditional technical scheme, and the heat exchange efficiency is high. The fluidized bed dryer has no pressure-bearing metal heat exchange surface, so that the equipment investment is low, the maintenance workload is small, and the cost is saved. The whole system is high in automation degree.

Description

Technical Field

[0001] The utility model relates to the technical field of gypsum solid waste resource recycling, in particular to a flue gas desulfurization gypsum drying device. Background Art

[0002] Desulfurization gypsum refers to waste with gypsum as the main component produced in the process of exhaust gas desulfurization. According to the provisions of GB / T 39198 "Classification and Code of General Solid Wastes", the category code of desulfurization gypsum is 65, which belongs to general solid waste. Furthermore, "Flue Gas Desulfurization Gypsum" in GB / T 37785-2019 "Flue Gas Desulfurization Gypsum" refers to solid waste with calcium sulfate dihydrate (CaSO4·2H2O) as the main component produced by desulfurization and purification of sulfur-containing flue gas using limestone / lime-gypsum wet method.

[0003] The vast majority of thermal power plants in my country use the limestone / lime-gypsum wet desulfurization process, and more than 100 million tons of flue gas desulfurization gypsum are produced each year, which is difficult to dispose of and reuse properly. Especially in areas with dense thermal power plants, large amounts of desulfurization gypsum accumulate, occupying land and polluting the environment, becoming a "chronic disease" in local environmental governance.

[0004] Flue gas desulfurization gypsum contains 10-15% free water. If it is to be used as a resource, the first step is to remove the free water and turn it into a dry powder material. The traditional dehydration method uses hot flue gas or steam as a heat source to dry the wet gypsum. For example, patent CN109970375A uses flue gas as a heat source for heating. This method has the following disadvantages: Since both hot flue gas and steam have less heat per unit volume and the temperature difference is too small, the equipment volume is large and the floor space is large. At the same time, the energy utilization efficiency and heat transfer effect of hot flue gas and steam are low, and the material is heated unevenly, resulting in uneven drying, which in turn causes unstable product quality. Therefore, hot flue gas and steam in the prior art have not been widely used as heat sources, and flue gas desulfurization gypsum can only be piled up and idle in a wet state. Therefore, there is an urgent need for a flue gas desulfurization gypsum drying device that can solve the above problems. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a flue gas desulfurization gypsum drying device.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A flue gas desulfurization gypsum drying device, characterized in that: it comprises a fluidized bed dryer, the fluidized bed dryer comprises a shell, an air distribution plate is installed in the shell, a wind box is installed on the lower side of the air distribution plate, a cavity of the shell on the upper side of the air distribution plate is provided with a dilute phase area and a dense phase area, and the dilute phase area is arranged on the upper side of the dense phase area;

[0008] There is a feed port for the wet material of flue gas desulfurization gypsum in the center of the top plate of the dilute phase zone, and a feed pipe is also connected inside the shell. The feed port of the feed pipe is arranged outside the head of the shell, and the discharge port of the feed pipe is arranged in the middle position of the lower side of the dense phase zone.

[0009] A cyclone separator is also installed in the fluidized bed dryer. The cyclone separator is installed at the tail of the fluidized bed dryer. The feed inlet of the cyclone separator is close to the top plate of the dilute phase zone. The gas outlet of the cyclone separator is arranged on the upper side of the shell. The discharge port on the lower side of the cyclone separator is connected to the discharge pipe. The discharge port of the discharge pipe is arranged on the outside of the shell. A main discharge port for inert particles is also provided on the air distribution plate at the tail of the fluidized bed dryer.

[0010] On the basis of the above scheme, the following technical scheme can also be adopted:

[0011] The horizontal vertical section of the dilute phase zone is a rectangle, the dense phase zone is a special-shaped cavity with a trapezoidal upper side and a rectangular lower side, and a wind cap is installed on the air distribution plate;

[0012] The horizontal length of the fluidized bed dryer is 2-4 times the width of the trapezoidal outlet;

[0013] The height of the dense phase area is 100-180 cm, and the height of the rectangle is 15-25 cm;

[0014] The trapezoid is a structure that is wide at the top and narrow at the bottom, and the angle between the side wall of the trapezoid and the horizontal plane is 60-65 degrees.

[0015] The distance between the feed port and the side wall of the fluidized bed dryer head is 20-50 cm.

[0016] The distance between the discharge port of the feed pipe and the side wall of the head of the fluidized bed dryer is 20-50 cm, and the distance between the discharge port and the wind cap on the air distribution plate is 5-10 cm.

[0017] A fluidizing air inlet is provided on the side wall of the wind box.

[0018] The main discharge port is a single large discharge port or a plurality of parallel small discharge ports.

[0019] The empty tower standard gas velocity at the bottom of the dense phase zone is 0.2-0.5 m / s.

[0020] The beneficial effects of the utility model are as follows: the device uses high-temperature particles of 750-950°C as a heat source, which has a huge temperature difference with the wet material of flue gas desulfurization gypsum, and has a good heat exchange effect. The high-temperature inert particles and the wet material of desulfurization gypsum are directly mixed for contact heat exchange. Both are particles of tens to hundreds of microns, with a huge specific surface area. Under the action of fluidization, the contact area between the two is much larger than the traditional technical solution, and the heat exchange efficiency is high. The fluidized bed dryer has no pressure-bearing metal heat exchange surface, low equipment investment, small maintenance workload, and cost savings. The overall system has a high degree of automation, continuous production under computer control, and greatly improved labor productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a basic structural schematic diagram of the utility model;

[0022] Figure 2 for Figure 1 Cross-sectional view in the AA direction;

[0023] Figure 3 for Figure 1 Cross-sectional view in the BB direction;

[0024] Figure 4 The utility model is a simplified flow chart of the drying system of the drying device. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "head", "tail", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0027] like Figure 1 , Figure 2 and Figure 3As shown, the utility model relates to a flue gas desulfurization gypsum drying device, including a fluidized bed dryer 13, and the fluidized bed dryer 13 is a horizontal structure. The fluidized bed dryer 13 includes a shell 1, an air distribution plate 2 is installed in the shell 1, and wind caps are evenly installed on the air distribution plate 2. The wind caps are prior art and are not drawn in the figure. A wind box 3 is installed on the lower side of the air distribution plate 2, and a fluidizing air inlet 12 is provided on the side wall of the wind box 3.

[0028] A dilute phase zone 4 and a dense phase zone 5 are provided in the cavity of the shell 1 on the upper side of the air distribution plate 2, and the dilute phase zone 4 is arranged on the upper side of the dense phase zone 5. The dilute phase zone 4 has a rectangular transverse vertical section, and the dense phase zone 5 is a special-shaped cavity with a trapezoid 5.1 on the upper side and a rectangle 5.2 on the lower side. The horizontal length of the fluidized bed dryer 13 is 2-4 times the outlet width of the trapezoid 5.1, and the preferred embodiment is 3 times. The height of the dense phase zone 5 is 100-180cm, and the preferred embodiment is 160cm. The height of the rectangle 5.2 is 15-25cm, and the preferred embodiment is 20cm. The trapezoid 5.1 is a structure that is wide at the top and narrow at the bottom, and the angle between the side wall of the trapezoid 5.1 and the horizontal plane is 60-65°, and the preferred embodiment is 62°. The empty tower standard gas velocity at the bottom of the dense phase zone 5 is 0.2-0.5m / s, and the preferred embodiment is 0.3m / s.

[0029] There is a feed port 6 for the flue gas desulfurization gypsum wet material in the center of the top plate head of the dilute phase zone 4. The distance between the feed port 6 and the side wall of the head of the fluidized bed dryer 13 is 20-50 cm, and the preferred embodiment is 35 cm. A feed pipe 7 is also connected to the shell 1. The feed port of the feed pipe 7 is arranged on the outside of the head of the shell 1, and the distance between the discharge port and the side wall of the head of the fluidized bed dryer 13 is 20-50 cm, and the preferred embodiment is 35 cm. The high-temperature inert particles are vertically fed into the central rectangular area at the bottom of the dense phase zone 5 through the feed pipe 7. The discharge port of the feed pipe 7 is arranged in the middle position of the lower side of the dense phase zone 5, and the distance between the discharge port and the wind cap on the air distribution plate 2 is 5-10 cm, and the preferred embodiment is 8 cm.

[0030] A cyclone separator 8 is also installed in the fluidized bed dryer 13. The cyclone separator 8 is installed at the tail of the fluidized bed dryer 13. The feed port of the cyclone separator 8 is close to the top plate of the dilute phase zone 4. The gas outlet 9 of the cyclone separator 8 passes upward through the top plate of the dilute phase zone 4 of the fluidized bed and is arranged on the upper side of the outer side of the shell 1. The discharge port on the lower side of the cyclone separator 8 is connected to the discharge pipe 10. The discharge port of the discharge pipe 10 passes downward through the trapezoidal side wall of the dense phase zone and is arranged on the outer side of the shell 1. A main discharge port 11 for inert particles is also provided on the air distribution plate 2 at the tail of the fluidized bed dryer 13. The main discharge port 11 is a single large discharge port or a plurality of parallel small discharge ports. The present solution preferably has a plurality of parallel small discharge ports.

[0031] The flue gas desulfurization gypsum drying device of this embodiment operates as follows:

[0032] The desulfurized gypsum wet material that meets the technical requirements of GB / T 37785-2019 "Flue Gas Desulfurization Gypsum" has a moisture content of 10-15%, and is fed into the cavity of the shell 1 from the feed inlet 6 at the head of the fluidized bed dryer 13, falls by free fall, passes through the dilute phase zone 4 and then falls into the dense phase zone 5.

[0033] The heat source used for drying is high-temperature inert particles, with a temperature of 750-950° C., preferably 850° C. The particles are fed from the feed port of the feed pipe 7 and enter the dense phase zone 5 of the fluidized bed dryer 13 through the pipeline.

[0034] The fluidizing air is sent into the wind box 3 from the fluidizing air inlet 12 to obtain stable pressure and uniform flow, and is blown into the dense phase zone 5 from the wind hood on the air distribution plate 2. The flow rate of the fluidizing air satisfies the empty tower standard gas velocity of 0.3m / s at the bottom of the dense phase zone of the fluidized bed dryer 13.

[0035] Under the action of fluidizing wind, the high-temperature inert particles and the wet flue gas desulfurization gypsum materials in the fluidized bed dryer 13 are in a fluidized state, undergoing intense heat exchange. The free water in the flue gas desulfurization gypsum is evaporated into water vapor, and the flue gas desulfurization gypsum is dried into a dry powder state. The increase in water vapor makes the fluidization more intense, accelerating the mixing and heat exchange of the materials.

[0036] The dense phase area 5 is in an inverted trapezoidal shape, which is wide at the top and narrow at the bottom, forming an internal circulation flow field of "spring in the center and sinks on both sides", which is conducive to the mixing and heat exchange of materials. The angle between the trapezoidal side wall surface of the dense phase area of ​​the fluidized bed dryer 13 and the horizontal plane is 62°, which avoids the dead zone of non-fluidization caused by material accumulation.

[0037] After the flue gas desulfurization gypsum and high-temperature inert particles are fed into the head of the fluidized bed dryer 13, they gradually move toward the tail while mixing and exchanging heat. The horizontal length of the fluidized bed dryer 13 is three times the width of the trapezoidal outlet of its dense phase zone, which ensures that the material particles have enough residence time to complete thorough heat exchange and evaporate all the free water in the flue gas desulfurization gypsum.

[0038] In order to achieve the drying effect, the flow rate of the flue gas desulfurization gypsum wet material and the high-temperature inert particles is adjusted to match the terminal temperature of the dense phase zone of the fluidized bed dryer 13 to 105-130°C, and the preferred temperature in this solution is 120°C to achieve complete evaporation of free water.

[0039] The particle size of the flue gas desulfurization gypsum dry powder particles is several tens of μm, and the particle size of the inert particles is 200-600 μm. The fluidized air exhaust gas and the evaporated water vapor carry the gypsum particles and some inert particles into the cyclone separator 8. Under the action of the cyclone separation, the fluidized air exhaust gas and the water vapor carry the gypsum dry powder particles and are discharged from the gas outlet 9 of the cyclone separator 8, and the inert particles are discharged from the discharge pipe 10 of the cyclone separator. Since the particle sizes of the flue gas desulfurization gypsum dry powder and the inert particles are different, the function of the cyclone separator 8 is to ensure the fine separation of the gypsum dry powder and the inert particles, improve the purity of the gypsum dry powder, and avoid the waste of inert particles.

[0040] Most of the inert particles are discharged from the main discharge port 11 from the air distribution plate at the rear of the fluidized bed dryer 13, and merge with the inert particles discharged from the discharge pipe 10 to be recycled.

[0041] Combination Figure 4 As shown, in order to realize industrialized continuous production, the drying method of the drying device of this embodiment is:

[0042] S1. The flue gas desulfurization gypsum wet material is stored in a wet material storage bin 14 and fed into a fluidized bed dryer 13 through a feeding device 15.

[0043] S 2. The high-temperature inert particle generator 16 produces high-temperature particles at 750-950° C. according to actual needs, and the particles are also sent to the fluidized bed dryer 13 .

[0044] S3. Under the action of the fluidizing fan 17, the solid particulate materials in the fluidized bed dryer 13 are in a fluidized state, undergoing intense heat exchange, and the flue gas desulfurization gypsum is dried into a dry powder state.

[0045] S4, fluidized air exhaust gas and water vapor carry gypsum particles and some inert particles into the cyclone separator 8. Under the action of the cyclone separation, the fluidized air exhaust gas and water vapor carry gypsum dry powder particles and are discharged from the gas outlet 9 and enter the bag collector 18. The inert particles are discharged from the discharge pipe 10, and after being combined with the inert particles discharged from the main discharge port 11, they are returned to the high-temperature inert particle generator 16.

[0046] S5. The bag collector 18 realizes gas-solid separation. The fluidized air exhaust gas and water vapor are discharged through the exhaust pipe 20 under the action of the induced draft fan 19. The gypsum dry powder particles are sent to the storage bin 21 or for subsequent processing and utilization.

[0047] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the utility model and are not used to limit the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A flue gas desulfurization gypsum drying device, characterized in that: The fluidized bed dryer (13) comprises a shell (1), an air distribution plate (2) is installed in the shell (1), a wind box (3) is installed on the lower side of the air distribution plate (2), and a dilute phase zone (4) and a dense phase zone (5) are provided in the cavity of the shell (1) on the upper side of the air distribution plate (2), and the dilute phase zone (4) is arranged on the upper side of the dense phase zone (5); A feed port (6) for the flue gas desulfurization gypsum wet material is provided in the center of the top plate of the dilute phase zone (4). A feed pipe (7) is also connected to the shell (1). The feed port of the feed pipe (7) is arranged outside the head of the shell (1), and the discharge port of the feed pipe (7) is arranged in the middle position of the lower side of the dense phase zone (5). A cyclone separator (8) is also installed in the fluidized bed dryer (13). The cyclone separator (8) is installed at the rear of the fluidized bed dryer (13). The feed inlet of the cyclone separator (8) is close to the top plate of the dilute phase zone (4). The gas outlet (9) of the cyclone separator (8) is arranged on the upper side of the shell (1). The discharge port on the lower side of the cyclone separator (8) is connected to the discharge pipe (10). The discharge port of the discharge pipe (10) is arranged on the outer side of the shell (1). A main discharge port (11) for inert particles is also provided on the air distribution plate (2) at the rear of the fluidized bed dryer (13).

2. A flue gas desulfurization gypsum drying device according to claim 1, characterized in that: The dilute phase zone (4) has a rectangular transverse vertical cross section, the dense phase zone (5) is a special-shaped cavity with a trapezoidal upper side (5.1) and a rectangular lower side (5.2), and a wind cap is installed on the air distribution plate (2); The horizontal length of the fluidized bed dryer (13) is 2-4 times the width of the trapezoidal outlet (5.1); The height of the dense phase region (5) is 100-180 cm, and the height of the rectangle (5.2) is 15-25 cm; The trapezoid (5.1) is a structure that is wide at the top and narrow at the bottom, and the angle between the side wall surface of the trapezoid (5.1) and the horizontal plane is 60-65 degrees.

3. A flue gas desulfurization gypsum drying device according to claim 1, characterized in that: The distance between the feed port (6) and the head side wall of the fluidized bed dryer (13) is 20-50 cm.

4. A flue gas desulfurization gypsum drying device according to claim 1, characterized in that: The distance between the discharge port of the feed pipe (7) and the side wall of the head of the fluidized bed dryer (13) is 20-50 cm, and the distance between the discharge port and the wind cap on the air distribution plate (2) is 5-10 cm.

5. A flue gas desulfurization gypsum drying device according to claim 1, characterized in that: A fluidizing air inlet (12) is provided on the side wall of the wind box (3).

6. A flue gas desulfurization gypsum drying device according to claim 1, characterized in that: The main discharge outlet (11) is a single large discharge outlet or a plurality of parallel small discharge outlets.

7. A flue gas desulfurization gypsum drying device according to claim 1, characterized in that: The empty tower standard gas velocity at the bottom of the dense phase zone (5) is 0.2-0.5 m / s.

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