Desulfurized gypsum dechlorination upgrading process system

Abstract

The invention discloses a desulfurization gypsum dechlorination and upgrading process system, and belongs to the technical field of alpha semi-hydrated gypsum production. In a material cascade drying system of the process, a material outlet of a reaction device is communicated with a material inlet of a high-pressure slurry separation and dehydration device; a material outlet of the high-pressure slurry separation and dehydration device is communicated with a material inlet of the flash evaporation device, a material outlet of the flash evaporation device is communicated with a material inlet of the high-temperature drying device, and a separated steam outlet of the flash evaporation device is communicated with a steam inlet of the solid-liquid mixing device; a separated water outlet of the high-pressure slurry separation and dehydration device is communicated with a high-pressure inlet of the multi-stage water circulation system, a separated water outlet of the flash evaporation device is communicated with a steam inlet of the raw material reaction system, and a separated water outlet of the high-temperature drying device is communicated with a low-pressure inlet of the multi-stage water circulation system. According to the process, the energy consumption of the system is reduced through a cascade drying method, drying water with different pressures is effectively utilized through a multi-stage water circulation system, and the heat loss of the system is reduced through heat recovery.

Description

Technical Field

[0001] The invention relates to the technical field of alpha hemihydrate gypsum production, and in particular to a desulfurized gypsum dechlorination and upgrading process system. Background Art

[0002] Desulfurized gypsum is a by-product of the boiler combustion system tail gas device, and its main component is dihydrate gypsum (CaSO 4 ·2H 2 O), as a solid waste, it is harmful to the environment, especially because desulfurized gypsum also contains chloride ions, which have adverse effects on groundwater and soil. Traditional desulfurized gypsum treatment methods are mostly green landfills, but this disposal method has low efficiency, large land occupation, high processing costs, and is prone to leakage. The most common way to recycle desulfurized gypsum is to process it into β-hemihydrate gypsum (β-CaSO 4 0.5H 2 O), used as building gypsum, but its added value is low and its market application is limited by the development of the construction industry. Compared with β-hemihydrate gypsum, α-hemihydrate gypsum (α-CaSO 4 0.5H 2 O, also known as high-strength gypsum) has good working performance, mechanical properties, thermal stability, biocompatibility, environmental protection performance and chemical corrosion resistance. It can be used in precision casting, high-end building materials, arts and crafts, medical treatment, aviation, shipbuilding and other fields. It can also be used in high-end fireproof building materials and is an important raw material in high-end manufacturing.

[0003] The traditional production process of α-hemihydrate gypsum is mostly autoclaving, which cannot effectively remove chloride ions, has high requirements on the quality of raw materials, and the process cannot be operated continuously, so the production cost is high. When desulfurized gypsum is used as the production raw material, the chloride ion content exceeds the standard, which easily causes the yield of the finished α-hemihydrate gypsum to be low, and the strength, whiteness and water absorption cannot meet the actual application requirements. The hydrothermal method can effectively remove the chloride ions in the desulfurized gypsum, and the quality of the finished α-hemihydrate gypsum obtained after the reaction is completed can meet the actual application standards. The principle of the hydrothermal method is to place the desulfurized gypsum slurry in a high-temperature and high-pressure water environment for reaction. During the reaction, the desulfurized gypsum crystals are dissolved in high-temperature and high-pressure water, and then crystallized again into α-hemihydrate gypsum. The crystals formed in this process are well-developed and stable in crystal form, and the chloride ions in the lattice can be dissolved in high-temperature and high-pressure water, achieving excellent dechlorination and quality improvement effects. However, the finished gypsum after the hydrothermal reaction will react with water at room temperature to regenerate dihydrate gypsum, reducing the qualified rate of the finished material. Therefore, the slurry after the reaction needs to be dried at a higher temperature. However, the drying process usually uses a direct or partition drying device such as a drum dryer, which has low drying efficiency and consumes a lot of heat and high energy consumption. Summary of the invention

[0004] In view of the above problems, the present invention provides a desulfurized gypsum dechlorination and upgrading process system, which effectively solves the technical problems of intermittent production and high energy consumption in the process of preparing α-hemihydrate gypsum from desulfurized gypsum. The process can effectively reduce the energy consumption in the drying process of gypsum slurry through a cascade drying system in the process of continuous production of α-hemihydrate gypsum, and at the same time treat drying water of different pressures through a multi-stage water circulation system, which has the effect of saving water resources, and reduces the heat loss of the system through heat recovery, thereby reducing the desulfurized gypsum processing cost and the production cost of α-hemihydrate gypsum, and increasing the economy of the system.

[0005] The invention provides a desulfurized gypsum dechlorination and upgrading process system, comprising a raw material reaction system, a material cascade drying system, a multi-stage water circulation system, a material post-processing system and a steam heating system.

[0006] The material cascade drying system comprises a high-pressure slurry separation and dehydration device, a flash evaporation device and a high-temperature drying device which are sequentially connected in series.

[0007] The material outlet of the raw material reaction system is connected to the material inlet of the high-pressure slurry separation and dehydration device, the material outlet of the high-pressure slurry separation and dehydration device is connected to the material inlet of the flash evaporation device, and the material outlet of the flash evaporation device is connected to the material inlet of the high-temperature drying device.

[0008] The separation water outlet of the high-pressure slurry separation and dehydration device is connected to the high-pressure inlet of the multi-stage water circulation system, the separation steam outlet of the flash evaporation device is connected to the steam inlet of the raw material reaction system, and the separation water outlet of the high-temperature drying device is connected to the low-pressure inlet of the multi-stage water circulation system.

[0009] The high-temperature drying device is connected to the material post-processing system; the steam heating system is connected to the raw material reaction system and the high-temperature drying device respectively.

[0010] In a preferred embodiment of the present invention, the multi-stage water circulation system includes a first heat exchanger, a second heat exchanger, a back pressure valve and a tail water treatment device.

[0011] The hot side inlet of the first heat exchanger is a low-pressure inlet of a multi-stage water circulation system, the hot side inlet of the first heat exchanger is connected to the separation water outlet of a high-temperature drying device, and the cold side inlet of the first heat exchanger is connected to the industrial water inlet.

[0012] The hot side inlet of the second heat exchanger is the high-pressure inlet of the multi-stage water circulation system, and the hot side inlet of the second heat exchanger is connected to the separation water outlet of the high-pressure slurry separation and dehydration device.

[0013] The inlet of the back pressure valve is communicated with the outlet of the second heat exchanger, and the hot side outlet of the first heat exchanger is communicated with the outlet of the back pressure valve through a circulating water collecting pipeline.

[0014] The circulating water collecting pipeline includes a first separation pipeline and a second separation pipeline, the first separation pipeline is connected to the water inlet of the solid-liquid mixing device, and the second separation pipeline is connected to the inlet of the tail water treatment device.

[0015] In a preferred embodiment of the present invention, the high-pressure slurry separation and dehydration device includes a solid-liquid self-separation device and a pressure energy utilization type solid phase pressure reduction and dehydration module.

[0016] In a preferred embodiment of the present invention, the raw material reaction system includes a material pretreatment system and a hydrothermal reaction system.

[0017] The material pretreatment system includes a raw material storage device, a crystal control agent tank and a solid-liquid mixing device. The outlet of the raw material storage device is connected to the material inlet of the solid-liquid mixing device, the outlet of the crystal control agent tank is connected to the crystal control agent inlet of the solid-liquid mixing device, and the solid-liquid mixing device is connected to the hydrothermal reaction system through a slurry pump.

[0018] In a preferred embodiment of the present invention, the hydrothermal reaction system comprises a reaction device, the inlet of the reaction device is connected to the slurry outlet of the solid-liquid mixing device; the outlet of the reaction device is connected to the inlet of the high-pressure slurry separation and dehydration device.

[0019] The reaction device is heated by steam provided by the steam heating system.

[0020] In a preferred embodiment of the present invention, the first outlet of the steam heating system is communicated with the steam heating inlet in the reaction device, and the second outlet of the steam heating system is communicated with the high-temperature steam inlet of the high-temperature drying device.

[0021] In a preferred embodiment of the present invention, the material post-processing system comprises a ball milling device, a finished material storage device and a finished material packaging device which are sequentially connected in series.

[0022] The inlet of the ball milling device is communicated with the material outlet of the high-temperature drying device.

[0023] In a preferred embodiment of the present invention, the pressure value of the back pressure valve, the pressure value of the reaction device and the pressure value of the high-pressure slurry separation and dehydration device are consistent.

[0024] In a preferred embodiment of the present invention, an industrial circulating water switch regulating valve is provided on the pipeline connecting the industrial water inlet and the first heat exchanger.

[0025] In a preferred embodiment of the present invention, an external drainage switch regulating valve is provided on the pipeline connecting the circulating water collecting pipeline and the tail water treatment device.

[0026] In a preferred embodiment of the present invention, a circulating water switch regulating valve and a chloride ion content detection instrument are provided on the pipeline connecting the circulating water collecting pipeline and the solid-liquid mixing device.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention realizes wet separation, flash separation and high-temperature drying separation of water in the α-hemihydrate gypsum slurry after the reaction is completed through the material cascade drying system, thereby reducing the drying energy consumption of the system; at the same time, the material cascade drying system always maintains a high temperature, avoiding the phase reversal of the α-hemihydrate gypsum during the drying process, thereby ensuring the qualified rate of the product.

[0028] (2) The present invention fully recovers the heat in the drying separation water through a multi-stage water circulation system based on the characteristics of the separation water in the material cascade drying system, and recovers the pressure energy of the high-pressure slurry, which has a good energy-saving effect; at the same time, new industrial water needs to be injected only when the chlorine content of the circulating water exceeds the limit value, which reduces the water consumption of the process system and effectively improves the system economy.

[0029] (3) The crystal control agent provided by the crystal control agent tank can be used in both the crystal phase transformation process and the dechlorination process, which increases the reuse rate of the crystal control agent tank and improves the economy of the system.

[0030] (4) The present invention realizes the efficient and clean conversion of desulfurized gypsum into α-hemihydrate gypsum through a series of processes including blending, hydrothermal reaction treatment, drying, grinding and packaging. On the premise of realizing resource utilization and efficient dechlorination of desulfurized gypsum, the present invention solves the problems of continuous production, high energy consumption and water consumption of the process system, thereby improving the economy of the system and promoting the industrial-scale application of the process method. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a desulfurized gypsum dechlorination and upgrading process system provided by the present invention.

[0032] Figure numerals: 1-raw material storage device; 2-solid-liquid mixing device; 3-slurry pump; 4-reaction device; 5-high-pressure slurry separation and dehydration device; 6-flash evaporation device; 7-high-temperature drying device; 8-finished product packaging device; 9-finished product storage device; 10-ball milling device; 11-first heat exchanger; 12-second heat exchanger; 13-dechlorination device; 14-back pressure valve; 15-crystal control agent tank; 16-tail water treatment device; V01-industrial water switch regulating valve; V02-external drainage switch regulating valve; V03-circulating water switch regulating valve; Cl01-chloride ion content detection instrument; R1-desulfurized gypsum; R2-saturated steam; R3-industrial water; R4-calcium hydroxide inlet. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0037] The main component of desulfurized gypsum is dihydrate gypsum (CaSO 4 ·2H 2 O), as a solid waste, needs to be treated harmlessly and recycled. Desulfurized gypsum contains chloride ions, which will affect the semi-hydrated gypsum (CaSO 4 0.5H 2 O) water absorption performance and strength. However, the traditional method of treating chloride ions is mainly through water washing technology, but this technology consumes a lot of water, consumes a lot of drying energy, and has poor economic efficiency. Therefore, it is necessary to provide a more economical method for resource utilization of desulfurized gypsum.

[0038] The most common way to recycle desulfurized gypsum is to process it into β-hemihydrate gypsum (β-CaSO 4 0.5H 2 O), used as building gypsum, but its added value is low. Compared with β-hemihydrate gypsum, α-hemihydrate gypsum (α-CaSO 4 0.5H 2 O) has better performance and economic value, and is the development direction of resource utilization of desulfurized gypsum. The traditional production process of α-hemihydrate gypsum is mostly autoclaving, which has high requirements on raw material quality, and the process cannot be operated continuously, and the production cost is high. The preparation of α-hemihydrate gypsum based on the hydrothermal method has lower requirements on raw materials, can use desulfurized gypsum as raw material, and can effectively reduce the chloride ions in the finished product. It has good development prospects, but the problem of high energy consumption in the drying process needs to be solved urgently.

[0039] Based on this, in order to solve the problem of high energy consumption in the drying process for resource utilization of desulfurized gypsum, the present invention provides a desulfurized gypsum dechlorination and upgrading process system, which reduces the drying energy consumption of the system through step drying, and improves the reuse level of water and heat through a multi-stage water recycling system, thereby realizing the continuous production of desulfurized gypsum and a significant reduction in its cost.

[0040] like Figure 1 The present invention provides a desulfurized gypsum dechlorination and upgrading process system, which includes a material pretreatment system, a hydrothermal reaction system, a material cascade drying system, a material post-treatment system, a multi-stage water circulation system and a steam heating system. It should be noted that Figure 1 The dotted lines in the figure refer to the paths of water and steam, and the solid lines refer to the path of the slurry.

[0041] The material cascade drying system includes a high-pressure slurry separation and dehydration device 5, a flash evaporation device 6 and a high-temperature drying device 7 which are connected in series in sequence. The outlet of the hydrothermal reaction system is connected to the material inlet of the high-pressure slurry separation and dehydration device 5 through a pipeline, the material outlet of the high-pressure slurry separation and dehydration device 5 is connected to the material inlet of the flash evaporation device 6, the separation water outlet of the high-pressure slurry separation and dehydration device 5 is connected to the high-pressure inlet of the multi-stage water circulation system, the material outlet of the flash evaporation device 6 is connected to the material inlet of the high-temperature drying device 7, the separation steam outlet of the flash evaporation device 6 is connected to the steam inlet of the solid-liquid mixing device 2, and the separation water outlet of the high-temperature drying device 7 is connected to the low-pressure inlet of the multi-stage water circulation system.

[0042] When the material after the reaction is completed is dried, it first enters the high-pressure slurry separation and dehydration device 5 for wet separation, and high-pressure water and high-pressure dehydrated slurry are separated. The separated high-pressure dehydrated slurry is transported to the flash evaporation device 6 through the material outlet of the high-pressure slurry separation and dehydration device 5, and flash evaporated under low pressure. After the flash evaporation, low-pressure dehydrated slurry and low-pressure water are obtained. The low-pressure dehydrated slurry enters the high-temperature drying device 7 through the material outlet of the flash evaporation device 6 for high-temperature drying to obtain dry finished α hemihydrate gypsum.

[0043] A high-pressure slurry separation and dehydration device 5, a flash evaporation device 6 and a high-temperature drying device 7 are arranged in the material cascade drying system. Since part of the water has been removed by wet separation and flash evaporation separation before high-temperature drying, and these two processes make full use of the static principle and pressure energy, the dehydration amount required in the high-temperature drying stage is reduced, thereby reducing the drying energy consumption.

[0044] The high-pressure slurry separation and dehydration device 5 includes a solid-liquid self-separation device and a pressure-energy-utilizing solid-phase pressure-reducing and dehydration component. The pressure-energy-utilizing solid-phase pressure-reducing and dehydration component utilizes the pressure difference when the high-pressure slurry is converted to low pressure to recover energy, and dehydration is performed through the solid-liquid group separation device and pressure-reducing centrifugation. The high-pressure slurry separation and dehydration device 5 set in the present invention can achieve the dual purposes of energy recovery and dehydration.

[0045] The high-temperature drying device 7 adopts a partition heating method, such as a partition heater, and the heat source is high-temperature steam; the high-temperature steam inlet is connected to the outlet of the steam heating system, and the heat source side outlet of the high-temperature drying device 7, such as the hot side outlet of the partition heater, is recycled or discharged according to the form of the steam source.

[0046] The multi-stage water circulation system includes a first heat exchanger 11, a second heat exchanger 12, a back pressure valve 14, and a tail water treatment device 16. The hot side inlet of the first heat exchanger 11 is the low-pressure inlet of the multi-stage water circulation system. The hot side inlet of the first heat exchanger 11 is connected to the separation water outlet of the high-temperature drying device 7, and the cold side inlet of the first heat exchanger 11 is connected to the industrial water inlet.

[0047] The hot side inlet of the second heat exchanger 12 is the high-pressure inlet of the multi-stage water circulation system, and the hot side inlet of the second heat exchanger 12 is connected to the separation water outlet of the high-pressure slurry separation and dehydration device 5; specifically, the outlet of the second heat exchanger 12 is communicated with the inlet of the dechlorination device 13, and the outlet of the dechlorination device 13 is communicated with the inlet of the back pressure valve 14, and the outlet of the back pressure valve 14 is communicated with the hot side outlet of the first heat exchanger 11 through a circulating water collecting pipeline; specifically, the hot side outlet of the first heat exchanger 11 and the outlet of the back pressure valve 14 are mixed in the circulating water collecting pipeline and divided into two paths, namely the first separation pipeline and the second separation pipeline, the first separation pipeline is connected to the water inlet of the solid-liquid mixing device 2, and the second separation pipeline is connected to the inlet of the tail water treatment device 16, and the pressure value of the back pressure valve 14 is consistent with the pressure value of the reaction device 4 and the pressure value of the high-pressure slurry separation and dehydration device 5.

[0048] The high-pressure separated water on the hot side of the second heat exchanger 12 enters the dechlorination device 13. The dechlorination device 13 is provided with a calcium hydroxide inlet and a crystal control agent inlet. Calcium hydroxide is added through the calcium hydroxide inlet of the dechlorination device 13, and the crystal control agent is added through the crystal control agent inlet of the dechlorination device 13. The crystal control agent and calcium hydroxide regulate the pH value of the slurry in the dechlorination device 13 for chloride ion removal.

[0049] The crystal controlling agent used in the present invention can be organic matter, aluminum sulfate and other compounds that can be used as crystal controlling agents.

[0050] During the operation of the multi-stage water circulation system, the high-pressure water obtained by wet separation through the high-pressure slurry separation and dehydration device 5 enters the second heat exchanger 12 from the separation water outlet of the high-pressure slurry separation and dehydration device 5, and after heat exchange, it is reduced in pressure through the back pressure valve 14 to obtain reduced-pressure high-pressure circulating water, and the reduced-pressure high-pressure circulating water reaches the circulating water collecting pipeline.

[0051] The low-pressure water obtained after flash evaporation in the flash evaporation device 6 enters the first heat exchanger 11 from the low-pressure separation water outlet of the high-temperature drying device 7, and after heat exchange, reaches the circulating water collection pipeline, and is mixed with the high-pressure circulating water after pressure reduction. According to its chloride ion content, the mixed circulating water enters the solid-liquid mixing device 2 or the tail water treatment device 16.

[0052] In the multi-stage water circulation system, an industrial circulating water switch regulating valve V01 is provided on the pipeline connecting the industrial water inlet with the first heat exchanger 11, an external drainage switch regulating valve V02 is provided on the pipeline connecting the circulating water collecting pipeline with the tail water treatment device 16, and a circulating water switch regulating valve V03 and a chloride ion content detection instrument Cl01 are provided on the pipeline connecting the circulating water collecting pipeline with the solid-liquid mixing device 2.

[0053] The operation mode of the multi-stage water circulation system is divided into two working conditions. The first working condition is that the chloride ion content value in the separated water fed back by the chloride ion content detection instrument Cl01 is lower than the maximum limit. At this time, the industrial circulating water switch regulating valve V01 is closed, the circulating water switch regulating valve V03 is opened, and the external drainage switch regulating valve V02 is opened and adjusted to the difference between the normal pressure separation water volume and the water volume required by the solid-liquid mixing device 2 to maintain the water volume demand of the solid-liquid mixing device 2.

[0054] The second operating condition is that the chloride ion content value in the separated water fed back by the chloride ion content detection instrument Cl01 is higher than the maximum limit. At this time, the industrial circulating water switch regulating valve V01 is opened and adjusted to the water volume required by the solid-liquid mixing device 2, the external drainage switch regulating valve V02 is closed, and the circulating water switch regulating valve V03 is closed to meet the maximum limit of chloride ion removal from the hydrothermal reaction slurry.

[0055] The present invention is further provided with the material pretreatment system before the material step drying system, and the material pretreatment system includes a raw material storage device 1, a crystal control agent tank 15 and a solid-liquid mixing device 2, and the solid-liquid mixing device 2 includes 4 inlets, namely a material inlet, a crystal control agent inlet, a water inlet and a steam inlet. The outlet of the raw material storage device 1 is connected to the material inlet of the solid-liquid mixing device 2, and the outlet of the crystal control agent tank 15 is connected to the crystal control agent inlet of the solid-liquid mixing device 2 and the crystal control agent inlet of the dechlorination device 13 respectively, and the solid-liquid mixing device 2 is connected to the hydrothermal reaction system through a slurry pump 3.

[0056] In the material pretreatment system, the material in the raw material storage device 1 enters the solid-liquid mixing device 2 through a screw conveyor for raw material proportioning and mixing into slurry. Compared with manually preparing the slurry in two slurry mixing tanks and then supplying it to the reaction device 4 in time, the material pretreatment system provided by the present invention has the following advantages: first, it reduces energy consumption, second, it improves the level of automated operation, and third, it can use circulating water in real time.

[0057] The raw materials in the raw material storage device 1 and the crystal control agent in the crystal control agent tank 15 are respectively transported to the solid-liquid mixing device 2 through the material inlet and the crystal control agent inlet, and water is injected through the water inlet of the solid-liquid mixing device 2, and steam is injected through the steam inlet of the solid-liquid mixing device 2 to mix the materials, crystal control agent, water and steam. An agitator is provided inside the solid-liquid mixing device 2 for solid-liquid mixing. After mixing, the slurry is transported to the hydrothermal reaction system through a slurry pump.

[0058] The hydrothermal reaction system includes a reaction device 4, the interior of the reaction device 4 is stirred by a stirrer or a drum, and a steam injection heating method is adopted, the injected steam is directly mixed with the slurry to maintain the temperature and pressure of the hydrothermal reaction, and the steam source is a steam heating system. Compared with the partition wall type and volumetric heating, the present invention directly mixes the slurry and steam during the reaction process to increase the slurry temperature, and the reaction device 4 will rotate as a whole during the reaction process, which can effectively improve the heat utilization efficiency and prevent the material from precipitating in the cylinder.

[0059] The slurry after mixing in the solid-liquid mixing device 2 is transported to the reaction device 4 through the slurry pump 3 for reaction. The steam required in the reaction process is provided by the steam heating system. The product after the hydrothermal reaction can enter the material cascade drying system for drying treatment.

[0060] After the hydrothermal reaction is completed, the product obtained can be dried and then enter the material post-processing system for post-processing, and the material post-processing includes a ball milling device 10, a finished material storage device 9 and a finished material packaging device 8 connected in series. The dried material is ball-milled to a desired particle size by the ball milling device 10, and then stored in the finished material storage device 9, and the stored material is packaged in the finished material packaging device 8.

[0061] The outlet of the steam heating system is divided into two routes, one route is connected to the steam heating inlet of the reaction device 4, and the other route is connected to the high-temperature steam inlet of the high-temperature drying device 7; the steam source of the steam heating system includes but is not limited to coal-fired boilers, biomass-fired boilers, gas boilers, electric heating boilers and purchased steam.

[0062] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0063] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A desulfurized gypsum dechlorination and upgrading process system, characterized in that: It includes raw material reaction system, material cascade drying system, multi-stage water circulation system, material post-processing system and steam heating system; The material cascade drying system comprises a high-pressure slurry separation and dehydration device (5), a flash evaporation device (6) and a high-temperature drying device (7) which are sequentially connected in series; The material outlet of the raw material reaction system is communicated with the material inlet of the high-pressure slurry separation and dehydration device (5), the material outlet of the high-pressure slurry separation and dehydration device (5) is communicated with the material inlet of the flash evaporation device (6), the material outlet of the flash evaporation device (6) is communicated with the material inlet of the high-temperature drying device (7), and the separation steam outlet of the flash evaporation device (6) is communicated with the steam inlet of the raw material reaction system; The separation water outlet of the high-pressure slurry separation and dehydration device (5) is connected to the high-pressure inlet of the multi-stage water circulation system, the separation water outlet of the flash evaporation device (6) is connected to the steam inlet of the raw material reaction system, and the separation water outlet of the high-temperature drying device (7) is connected to the low-pressure inlet of the multi-stage water circulation system; The high-temperature drying device (7) is in communication with the material post-processing system; and the steam heating system is in communication with the raw material reaction system and the high-temperature drying device (7), respectively.

2. A desulfurized gypsum dechlorination and upgrading process system according to claim 1, characterized in that: The multi-stage water circulation system comprises a first heat exchanger (11), a second heat exchanger (12), a back pressure valve (14) and a tail water treatment device (16); The hot side inlet of the first heat exchanger (11) is a low-pressure inlet of the multi-stage water circulation system, the hot side inlet of the first heat exchanger (11) is connected to the separation water outlet of the high-temperature drying device (7), and the cold side inlet of the first heat exchanger (11) is connected to the industrial water inlet; The hot side inlet of the second heat exchanger (12) is a high-pressure inlet of the multi-stage water circulation system, and the hot side inlet of the second heat exchanger (12) is connected to the separation water outlet of the high-pressure slurry separation and dehydration device (5); The outlet of the second heat exchanger (12) is in communication with the inlet of the dechlorination device (13), the outlet of the dechlorination device (13) is in communication with the inlet of the back pressure valve (14), and the outlet of the back pressure valve (14) is in communication with the hot side outlet of the first heat exchanger (11) via a circulating water collecting pipeline; The dechlorination device (13) is provided with a calcium hydroxide inlet and a crystal control agent inlet, calcium hydroxide is added through the calcium hydroxide inlet of the dechlorination device (13), and the crystal control agent is added through the crystal control agent inlet of the dechlorination device (13), and the crystal control agent and calcium hydroxide are used to regulate the pH value of the slurry in the dechlorination device (13) for removing chloride ions; The circulating water collecting pipeline comprises a first separation pipeline and a second separation pipeline, the first separation pipeline is connected to the water inlet of the solid-liquid mixing device (2), and the second separation pipeline is connected to the inlet of the tail water treatment device (16).

3. A desulfurized gypsum dechlorination and upgrading process system according to claim 1, characterized in that: The high-pressure slurry separation and dehydration device (5) comprises a solid-liquid self-separation device and a pressure energy utilization type solid phase pressure reduction and dehydration module.

4. A desulfurized gypsum dechlorination and upgrading process system according to claim 1, characterized in that: The raw material reaction system includes a material pretreatment system and a hydrothermal reaction system; The material pretreatment system comprises a raw material storage device (1), a crystal control agent tank (15) and a solid-liquid mixing device (2); the outlet of the raw material storage device (1) is connected to the material inlet of the solid-liquid mixing device (2); the outlet of the crystal control agent tank (15) is respectively connected to the crystal control agent inlet of the solid-liquid mixing device (2) and the crystal control agent inlet on the dechlorination device (13); and the solid-liquid mixing device (2) is connected to the hydrothermal reaction system via a slurry pump (3).

5. A desulfurized gypsum dechlorination and upgrading process system according to claim 4, characterized in that: The hydrothermal reaction system comprises a reaction device (4), the inlet of the reaction device (4) being connected to the slurry outlet of the solid-liquid mixing device (2); the outlet of the reaction device (4) being connected to the inlet of the high-pressure slurry separation and dehydration device (5); The heat source of the reaction device (4) comes from the steam provided by the steam heating system.

6. A desulfurized gypsum dechlorination and upgrading process system according to claim 5, characterized in that: The first outlet of the steam heating system is in communication with the steam heating inlet in the reaction device (4), and the second outlet of the steam heating system is in communication with the high-temperature steam inlet of the high-temperature drying device (7).

7. A desulfurized gypsum dechlorination and upgrading process system according to claim 1, characterized in that: The material post-processing system comprises a ball milling device (10), a finished material storage device (9) and a finished material packaging device (8) which are connected in series in sequence; The inlet of the ball milling device is connected to the material outlet of the high-temperature drying device (7).

8. A desulfurized gypsum dechlorination and upgrading process system according to claim 2, characterized in that: The pressure value of the back pressure valve (14), the pressure value of the reaction device (4), and the pressure value of the high-pressure slurry separation and dehydration device (5) are consistent.

9. A desulfurized gypsum dechlorination and upgrading process system according to claim 2, characterized in that: An industrial circulating water switch regulating valve (V01) is provided on the pipeline connecting the industrial water inlet and the first heat exchanger (11).

10. A desulfurized gypsum dechlorination and upgrading process system according to claim 2, characterized in that: An external drainage switch regulating valve (V02) is provided on a pipeline connecting the circulating water collection pipeline and the tail water treatment device (16); A circulating water switch regulating valve (V03) and a chloride ion content detection instrument (Cl01) are provided on a pipeline connecting the circulating water collecting pipeline and the solid-liquid mixing device (2).

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