Black water purification system

Abstract

A black water purification system relates to the technical field of black water treatment. The purification system comprises a first treatment system and a second treatment system, the first treatment system comprises flash evaporation equipment, a black water adjusting device, a slurry storage device, a steam compressor and drying equipment; the second treatment system comprises a first heat exchange device, a second heat exchange device, a third heat exchange device and a fourth heat exchange device; through combined operation of the two treatment systems, high-hardness solid particles contained in the black water are recycled in a filter cake form, the filter cake can be used as a building material, and resources are reasonably utilized while solid waste is reduced; in addition, the purification system not only can recover waste heat in the black water, but also can recover moisture in the black water, the discharge capacity in the technological production process is reduced, the obtained purified water is high in quality and can be used for technological water supplementation, the collected heat can be connected with a heat supply pipe network, and dual recovery of heat and purified water is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of black water treatment, in particular to a black water purification system. Background Art

[0002] Black water mainly refers to the solid-liquid mixture with coal slag formed by the coal gasification system. Most of the mixture is water, and contains highly corrosive substances such as ammonium ions, chloride ions, and hydrogen sulfide. It has the characteristics of high suspended matter, high temperature, high alkali, and high hardness. At the same time, there are also high-hardness solid particles produced by the gasification reaction in the black water, with a mass fraction of up to 10%. If it is directly discharged, it will cause waste of resources and bring solid waste pollution to the environment. The temperature of black water after flash evaporation in the chemical process is 70-80℃, and it contains a certain amount of process waste heat. If it is directly discharged, the waste heat cannot be reasonably utilized and will cause harm to the environment.

[0003] In view of this, the present application is also filed. Utility Model Content

[0004] The purpose of the utility model is to provide a coal gasification black water purification system, which can solve the above technical problems.

[0005] The embodiment of the utility model is achieved as follows:

[0006] In the first aspect, an embodiment of the utility model provides a black water purification system, which comprises a first treatment system and a second treatment system; the first treatment system comprises a flash evaporation device, a black water regulating device, a mud storage device, a steam compressor and a drying device; the flash evaporation device is provided with a water inlet, an air outlet and a liquid outlet for black water to be treated; the air outlet is connected to the drying device via a steam compressor; the liquid outlet is connected to the black water regulating device; the black water regulating device is connected to the mud storage device, and the mud storage device is connected to the drying device; the second treatment system comprises a first heat exchange device, a second heat exchange device, a third heat exchange device and a fourth heat exchange device; the first heat exchange device is provided with a first liquid inlet The first heat exchange device is connected to the third heat exchange device, and the third heat exchange device is connected to the first heat exchange device; the first air inlet is connected to the second heat exchange device, and the first air outlet is connected to the second heat exchange device; the second heat exchange device is provided with a second liquid inlet, a second liquid outlet, a second air inlet and a second air outlet, and the second liquid inlet is connected to the fourth heat exchange device; the second liquid outlet is connected to the third heat exchange device, and the third heat exchange device is connected to the fourth heat exchange device; the second air inlet is connected to the first air outlet of the first heat exchange device, and the second air outlet is connected to the first air inlet of the first heat exchange device.

[0007] In an optional embodiment, the black water regulating device is provided with a first black water inlet, a first black water outlet and a mud outlet; the first black water inlet is connected to the liquid outlet of the flash evaporation equipment; the first black water outlet is connected to the first liquid inlet of the first heat exchange device; and the mud outlet is connected to the mud storage device.

[0008] In an optional embodiment, the black water regulating device is also provided with a liquid inlet; the liquid inlet is connected to at least one of an acid and alkali reagent tank and / or a flocculant tank; inside the black water regulating device, a first spraying device is connected to the corresponding position of the liquid inlet.

[0009] In an optional embodiment, the mud storage device is provided with a first mud inlet, a second mud inlet and a mud outlet; the first mud inlet is connected to the mud outlet of the black water regulating device; the second mud inlet is connected to the first heat exchange device; and the mud outlet is connected to the drying equipment.

[0010] In an optional embodiment, the drying equipment is provided with a first feed port, a second feed port and a discharge port; the first feed port is connected to the steam compressor; the second feed port is connected to the mud discharge port of the mud storage device; the discharge port is connected to the collection device for recovering liquid or solid materials.

[0011] In an optional embodiment, a first demisting device is arranged between the first air outlet and the first liquid inlet of the first heat exchange device; a second spraying device is arranged inside the first heat exchange device at a position corresponding to the first liquid inlet; the first heat exchange device also has a first mud outlet, and the first mud outlet is connected to the second mud inlet of the mud storage device.

[0012] In an optional embodiment, a black water circulation device is arranged between the black water regulating device and the first heat exchange device; the black water circulation device is provided with a second black water inlet, a third black water inlet and a second black water outlet; the second black water inlet is connected to the first black water outlet of the black water regulating device; the third black water inlet is connected to the third heat exchange device; and the second black water outlet is connected to the first liquid inlet of the first heat exchange device.

[0013] In an optional embodiment, a second demisting device is provided between the second air outlet and the second liquid inlet of the second heat exchange device; and a third spraying device is provided inside the second heat exchange device at a position corresponding to the second liquid inlet.

[0014] In an optional embodiment, the third heat exchange device is provided with a third liquid inlet, a third liquid outlet, a fourth liquid inlet and a fourth liquid outlet; the third liquid inlet is connected to the first liquid outlet of the first heat exchange device; the third liquid outlet is connected to the third black water inlet of the black water circulation device; the fourth liquid inlet is connected to the second liquid outlet of the second heat exchange device; the fourth liquid outlet is connected to the fourth heat exchange device; and a water outlet is provided between the fourth liquid outlet and the fourth heat exchange device.

[0015] In an optional embodiment, the fourth heat exchange device is provided with a fifth liquid inlet, a fifth liquid outlet, a cold medium inlet and a hot medium outlet; the fifth liquid inlet is connected to the fourth liquid outlet of the third heat exchange device; the fifth liquid outlet is connected to the second liquid inlet of the second heat exchange device; and the cold medium inlet is connected to a cooling device.

[0016] The beneficial effects of the embodiments of the utility model are:

[0017] The black water purification system provided by the embodiment of the utility model comprises a first treatment system and a second treatment system; the first treatment system comprises a flash evaporation device, a black water regulating device, a mud storage device, a steam compressor and a drying device; the second treatment system comprises a first heat exchange device, a second heat exchange device, a third heat exchange device and a fourth heat exchange device; the first treatment system and the second treatment system are operated jointly, and the high-hardness solid particles contained in the black water are recovered in the form of filter cakes, and the filter cakes can be used as building materials, thereby reducing solid waste and making rational use of resources; in addition, the purification system can not only recover the waste heat in the black water, but also recover the moisture in the black water, thereby reducing the amount of sewage discharged in the process production process, and the obtained clean water has a higher quality and can be used for process water replenishment, and the collected heat can be connected to the heating pipeline network to realize the dual recovery of heat and clean water. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a coal gasification black water purification system provided in an embodiment of the utility model.

[0020] Icons: 10-black water purification system; 100-first treatment system; 101-inlet of black water to be treated; 103-liquid outlet; 105-gas outlet; 107-pressure regulating member; 109-steam compressor; 111-black water regulating device; 113-first black water inlet; 115-first black water outlet; 117-mud outlet; 119-liquid inlet; 120-first spraying device; 121-acid and alkali reagent storage device; 123-flocculant storage device; 13 0-mud storage device; 131-first mud inlet; 133-second mud inlet; 135-mud outlet; 140-drying equipment; 141-first feed inlet; 143-second feed inlet; 145-first outlet; 147-second outlet; 200-second treatment system; 300-black water circulation system; 301-first heat exchange device; 303-first air outlet; 305-first liquid inlet; 307-first liquid outlet; 309-first air inlet; 311-first First mud outlet; 312-first circulation pump; 313-first demisting device; 315-second spraying device; 317-second circulation pump; 320-black water circulation device; 321-second black water outlet; 323-second black water inlet; 325-third black water inlet; 330-third heat exchange device; 331-third liquid inlet; 333-third liquid outlet; 335-fourth liquid outlet; 337-fourth liquid inlet; 339-third circulation pump; 341-fourth circulation pump ; 343-fifth circulation pump; 345-sixth circulation pump; 400-purified water circulation system; 401-second heat exchange device; 403-second air outlet; 405-second liquid inlet; 407-second liquid outlet; 409-second air inlet; 411-second demisting device; 413-third spraying device; 420-fourth heat exchange device; 421-hot medium outlet; 423-cold medium inlet; 425-water inlet; 427-fifth liquid inlet; 429-fifth liquid outlet. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. 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.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply 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 utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0025] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description 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 communication 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.

[0027] First embodiment

[0028] Please refer to Figure 1 This embodiment provides a black water purification system 10, which includes a first treatment system 100 and a second treatment system 200; the first treatment system 100 includes a flash evaporation device, a black water regulating device 111, a mud storage device 130, a steam compressor 109 and a drying device 140.

[0029] It should be noted that the black water treated by the purification system in this embodiment mainly comes from the solid-liquid mixture with coal slag formed in the coal gasification system, that is, coal gasification black water, whose temperature is higher than 80°C. After flash evaporation by the flash evaporation equipment, the temperature of the black water is still above 70°C, containing a large amount of process waste heat. In other embodiments of the utility model, the purification system can also treat other industrial wastewater, for example, wastewater generated by industries such as petroleum and metallurgy.

[0030] The flash evaporation equipment is provided with a water inlet 101 for black water to be treated, an air outlet 105 and a liquid outlet 103; the air outlet 105 is connected to the drying equipment 140 via a steam compressor 109; the liquid outlet 103 is connected to the black water regulating device 111; the black water regulating device 111 is connected to the mud storage device 130, and the mud storage device 130 is connected to the drying equipment 140.

[0031] It should be noted that the flash evaporation equipment used in the utility model is a vacuum flash evaporation tank, which mainly performs flash evaporation on coal gasification black water to obtain black water condensate and steam. The specifications and models of the flash evaporation tank can be reasonably selected according to the actual amount of black water to be processed.

[0032] Specifically, coal gasification black water enters the flash evaporation equipment from the black water inlet 101 to be treated to produce black water condensate and steam, wherein the steam is output from the gas outlet 105, and is sent to the steam compressor 109 for treatment after being treated by the pressure regulating component 107 to obtain steam condensate and second steam; the steam condensate and the second steam are transported from the first feed port 141 to the drying equipment 140 for treatment.

[0033] It should be noted that the first feed port 141 is provided with pipes for transmitting steam condensate and second steam respectively, wherein the steam condensate is discharged from the second discharge port 147 of the drying equipment 140; the second steam transfers heat to the mud material in the drying equipment 140 for drying, and the obtained filter cake is discharged from the first discharge port 145, and the filter cake can be used as building materials.

[0034] The drying device 140 is equipped with a condenser (not shown in the figure). The exhaust steam generated by drying the mud is heat-exchanged with the outside air in the condenser of the drying device 140 to obtain drying exhaust steam condensate; the drying exhaust steam condensate is discharged from the second discharge port 147. It should be noted that the steam condensate and the drying exhaust steam condensate are used as clean water and can be used as process water. In other embodiments of the utility model, the filter cake and clean water can be reasonably used according to actual needs.

[0035] It should be noted that the pressure regulating member 107 provided on the steam delivery pipeline is used to monitor and facilitate operators to adjust the steam pressure from the flash evaporation equipment in real time to avoid damage to the steam compressor 109 due to excessive pressure.

[0036] Furthermore, the filter cake and purified water are output from the discharge port of the drying device 140. In this embodiment, two discharge ports are provided, namely the first discharge port 145 and the second discharge port 147. A suitable discharge port can be selected according to the actually connected collection device to collect the filter cake or purified water.

[0037] The black water condensate is output from the liquid outlet 103 , enters the black water regulating device 111 through the first black water inlet 113 , and is regulated in the black water regulating device 111 .

[0038] It should be noted that after the flash evaporation treatment of the coal gasification black water, the black water condensate will still be mixed with insoluble substances such as solid coal slag, and it needs to be subjected to sedimentation treatment after entering the black water regulating device 111, otherwise it will cause blockage to the subsequent equipment, affect the production, damage the equipment and increase the investment cost; the black water condensate also contains acidic substances such as hydrogen sulfide, and weak alkaline ions such as ammonium ions. In order to avoid the black water condensate from causing harm to the environment after it is finally discharged, it needs to be subjected to acid-base balance treatment.

[0039] Furthermore, at least one of the acid-base reagent and / or flocculant is sprayed into the black water regulating device 111 from the liquid inlet 119 of the black water regulating device 111 through the first spraying device 120, and the black water condensate is subjected to sedimentation treatment to obtain black water supernatant and black water sediment.

[0040] Specifically, the acid-base reagents are in the acid-base reagent storage device 121, and the flocculants are in the flocculant storage device 123. The materials of the acid-base reagent storage device 121 and the flocculant storage device 123 need to be reasonably selected according to the properties of the actual reagents placed.

[0041] Furthermore, the flocculant is selected from at least one of a polyaluminum sulfate solution and a polyaluminum chloride solution; the provision of the first spray device 120 increases the contact area between the drug and the black water condensate, and can efficiently perform acid-base adjustment and sedimentation treatment on the black water condensate; the addition of the flocculant can accelerate the sedimentation rate of insoluble matter, flocs or suspended matter in the black water condensate, preliminarily filter out impurities in the black water, and finally exist in the form of precipitation, thereby improving the cleanliness of the supernatant in the black water adjustment device 111; the acid-base balance agent can be reasonably adjusted according to the actual pH of the black water condensate. In this embodiment, a strong base sodium hydroxide solution is used to adjust the acid-base balance. In other embodiments of the utility model, strong alkaline substances such as potassium hydroxide and barium hydroxide can be selected according to actual conditions.

[0042] The black water sediment is output from the mud outlet 117, enters the mud storage device 130 through the first mud inlet 131 of the mud storage device 130 for storage, and the mud in the mud storage device 130 is output from the mud outlet 135 and enters the drying device 140 through the second feed inlet 143 of the drying device 140 for drying treatment to obtain filter cake and purified water, wherein the filter cake can be used as building materials, and the purified water can be used as process water. In other embodiments of the utility model, the filter cake and purified water can be reasonably used according to actual needs.

[0043] The black water supernatant is output from the first black water outlet 115, and is pumped into the black water circulation device 320 from the second black water inlet 323 through the action of the second circulation pump 317. The black water in the black water circulation device 320 is output from the second black water outlet 321, and enters the first heat exchange device 301 through the first liquid inlet 305 of the first heat exchange device 301.

[0044] Furthermore, the first liquid inlet 305 is arranged at the upper part of the first heat exchange device 301, so as to facilitate the heat exchange between the added black water and the cold dry air entering from the first air inlet 309 of the first heat exchange device 301 to obtain hot wet air and condensed black water, wherein the first air inlet 309 is arranged at the bottom of the first heat exchange device 301, and the condensed black water has process waste heat.

[0045] Furthermore, inside the first heat exchange device 301, a second spray device 315 is arranged corresponding to the first liquid inlet 305; a first demisting device 313 is arranged between the first air outlet 303 of the first heat exchange device 301 and the first liquid inlet 305; the second spray device 315 is arranged to accelerate the heat exchange efficiency between black water and cold dry air; the first demisting device 313 is arranged to reduce the amount of droplets entrained in the hot and humid air.

[0046] It should be noted that the black water treated by the first heat exchange device 301 is added from the black water circulation device 320 , and a small amount of insoluble matter may be mixed therein. The condensed black water is collected at the bottom of the first heat exchange device 301 .

[0047] The hot and humid air is output from the first air outlet 303 of the first heat exchange device 301, and is pumped into the second heat exchange device 401 from the second air inlet 409 of the second heat exchange device 401 through the fifth circulation pump 343, so as to be heat exchanged with the cold clean water coming in from the second liquid inlet 405 to obtain cold dry air and condensed water, wherein the second air inlet 409 is arranged at the bottom of the second heat exchange device 401, and the condensed water has a lower temperature.

[0048] The condensed black water with a relatively high temperature is collected at the bottom of the first heat exchange device 301, wherein the supernatant of the condensed black water is output from the first liquid outlet 307, and enters the third heat exchange device 330 from the third liquid inlet 331 via the third circulation pump 339; the sediment of the condensed black water is output from the first mud outlet 311 of the first heat exchange device 301, and is pumped into the mud storage device 130 from the second mud inlet 133 of the mud storage device 130 via the first circulation pump 312, mixed with the black water sediment input from the black water regulating device 111, and enters the drying device through the second feed port 143 for drying treatment.

[0049] The cold dry gas is output from the second air outlet 403 of the second heat exchange device 401, and is pumped into the first heat exchange device 301 from the first air inlet 309 of the first heat exchange device 301 through the sixth circulation pump 345 for heat exchange treatment. The cold dry gas enters from the bottom and hot black water is sprayed from the top to increase the contact area between water and gas and improve the heat exchange efficiency.

[0050] It should be noted that a second demisting device 411 is provided between the second air outlet 403 and the second liquid inlet 405 of the second heat exchange device 401; a third spraying device 413 is provided inside the second heat exchange device 401 at a position corresponding to the second liquid inlet 405. The third spraying device 413 is provided to accelerate the heat exchange efficiency between the cooled clean water and the hot humid air; the second demisting device 411 is provided to reduce the amount of liquid droplets entrained in the cold dry air.

[0051] The condensed water with a relatively low temperature is collected at the bottom of the second heat exchange device 401 , and is pumped into the third heat exchange device 330 from the second liquid outlet 407 at the bottom of the second heat exchange device 401 through the fourth liquid inlet 337 via the fourth circulation pump 341 .

[0052] After the condensed black water with a higher temperature and the condensed water with a lower temperature are fully heat exchanged in the third heat exchange device 330, low-temperature black water and high-temperature purified water are obtained. The low-temperature black water is output from the third liquid outlet 333, enters the black water circulation device 320 through the third black water inlet 325, mixes with the black water in the black water regulating device 111, and enters the first heat exchange device 301 together to form a black water circulation system 300. The high-temperature purified water is output from the fourth liquid outlet 335, and enters the fourth heat exchange device 420 through the fifth liquid inlet 427.

[0053] In this embodiment, a water inlet 425 is provided between the fourth liquid outlet 335 and the fourth heat exchange device 420 , and the water inlet 425 can be used to connect heat-using equipment, such as a heating network, household water, process water, etc.

[0054] The fourth heat exchange device 420 is provided with a fifth liquid inlet 427, a fifth liquid outlet 429, a cold medium inlet 423 and a hot medium outlet 421. The fifth liquid inlet 427 is connected to the fourth liquid outlet 335 of the third heat exchange device 330; the cold medium inlet 423 is connected to a cooling device for cooling the clean water entering the fourth heat exchange device 420, and then the cooled clean water is output through the fifth liquid outlet 429, enters the second heat exchange device 401 from the second liquid inlet 405, is sprayed from the third spray device 413, and performs heat exchange with the hot and humid air coming in from the second air inlet 409, thereby forming a clean water circulation system 400.

[0055] It should be noted that the hot humid air is condensed in the second heat exchange device 401, and the obtained condensed water is of high quality, which is similar to distilled water and can be used for process water replenishment.

[0056] After the low-temperature purified water is heat-exchanged in the fourth heat exchange device 420, the obtained high-temperature purified water is output through the heat medium outlet 421, and the heat medium can be used to connect heat-using equipment, such as heating pipe networks, household water, process water, etc.

[0057] It should be noted that the first to fourth heat exchangers in the present invention are all anti-corrosion and anti-scaling heat exchangers, which can effectively reduce the operation and maintenance costs. Among them, the first heat exchanger 301 and the second heat exchanger 401 are heat exchange towers, and the third heat exchanger 330 is a high-efficiency plate heat exchanger. In other embodiments of the present invention, a shell-and-tube heat exchanger or a shell-and-tube heat exchanger can be selected according to actual needs.

[0058] Please refer to Figure 1 The working principle of the black water purification system 10 provided by the utility model is as follows:

[0059] The black water to be treated is sequentially treated by the flash evaporation device to obtain black water condensate and steam, wherein the steam is treated by the steam compressor 109 and the drying device 140; the black water condensate is treated by the black water regulating device 111 to obtain the black water supernatant and black water sediment, and the black water sediment is treated by the mud storage device 130 and the drying device 140; in addition, the sediment of the condensed black water in the first heat exchange device 301 is treated by the mud storage device 130 and the drying device 140, and the above forms a treatment system for solid materials and insoluble substances mixed in the black water. The black water supernatant passes through the black water circulation device 320, the first heat exchange device 301, the third heat exchange device 330 and the black water circulation device 320 to form a black water circulation system 300. The clean water passes through the fourth heat exchange device 420, the second heat exchange device 401, the third heat exchange device 330 and the fourth heat exchange device 420 to form a clean water circulation system 400.

[0060] In summary, the blackwater purification system 10 provided in the embodiment of the utility model reduces solid waste while making rational use of resources under the joint treatment of the first treatment system 100 and the second treatment system 200. The purification system can not only recover the waste heat in the black water, but also recover the moisture in the black water, thereby reducing the amount of sewage discharged in the process production process. The obtained clean water is of high quality and can be used for process water replenishment. The collected heat can be connected to the heating pipeline network to achieve dual recovery of heat and clean water.

[0061] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A black water purification system, characterized in that: The purification system includes a first treatment system and a second treatment system; The first treatment system includes a flash evaporation device, a black water conditioning device, a mud storage device, a steam compressor and a drying device; The flash evaporation equipment is provided with a water inlet, a gas outlet and a liquid outlet for black water to be treated; the gas outlet is connected to the drying equipment via the steam compressor; the liquid outlet is connected to the black water regulating device; the black water regulating device is connected to the mud storage device, and the mud storage device is connected to the drying equipment; The second processing system includes a first heat exchange device, a second heat exchange device, a third heat exchange device, and a fourth heat exchange device; The first heat exchange device is provided with a first liquid inlet, a first liquid outlet, a first air inlet and a first air outlet, and the first liquid inlet is connected to the black water regulating device; the first liquid outlet is connected to the third heat exchange device, and the third heat exchange device is connected to the first heat exchange device; the first air inlet is connected to the second heat exchange device, and the first air outlet is connected to the second heat exchange device; The second heat exchange device is provided with a second liquid inlet, a second liquid outlet, a second air inlet and a second air outlet, the second liquid inlet is connected to the fourth heat exchange device; the second liquid outlet is connected to the third heat exchange device, and the third heat exchange device is connected to the fourth heat exchange device; the second air inlet is connected to the first air outlet of the first heat exchange device, and the second air outlet is connected to the first air inlet of the first heat exchange device.

2. The black water purification system according to claim 1, characterized in that: The black water regulating device is provided with a first black water inlet, a first black water outlet and a mud outlet; The first black water inlet is communicated with the liquid outlet of the flash evaporation device; the first black water outlet is communicated with the first liquid inlet of the first heat exchange device; and the mud outlet is communicated with the mud storage device.

3. The black water purification system according to claim 2, characterized in that: The black water regulating device is also provided with a liquid inlet; the liquid inlet is connected to at least one of an acid-base reagent tank and / or a flocculant tank; Inside the black water regulating device, a first spraying device is connected to a position corresponding to the liquid inlet.

4. The black water purification system according to claim 2, characterized in that: The mud storage device is provided with a first mud inlet, a second mud inlet and a mud outlet; The first mud inlet is communicated with the mud outlet of the black water regulating device; the second mud inlet is communicated with the first heat exchange device; and the mud outlet is communicated with the drying equipment.

5. The black water purification system according to claim 4, characterized in that: The drying equipment is provided with a first feed inlet, a second feed inlet and a discharge outlet; The first feed port is communicated with the steam compressor; the second feed port is communicated with the mud outlet of the mud storage device; the outlet is communicated with a collecting device for recovering liquid materials or solid materials.

6. The black water purification system according to claim 4, characterized in that: A first demisting device is provided between the first air outlet of the first heat exchange device and the first liquid inlet; a second spraying device is provided inside the first heat exchange device at a position corresponding to the first liquid inlet; The first heat exchange device is further provided with a first mud outlet, and the first mud outlet is communicated with the second mud inlet of the mud storage device.

7. The black water purification system according to claim 1, characterized in that: A black water circulation device is provided between the black water regulating device and the first heat exchange device; the black water circulation device is provided with a second black water inlet, a third black water inlet and a second black water outlet; The second black water inlet is connected to the first black water outlet of the black water regulating device; the third black water inlet is connected to the third heat exchange device; the second black water outlet is connected to the first liquid inlet of the first heat exchange device.

8. The black water purification system according to claim 1, characterized in that: A second demisting device is arranged between the second air outlet and the second liquid inlet of the second heat exchange device; and a third spraying device is arranged inside the second heat exchange device at a position corresponding to the second liquid inlet.

9. The black water purification system according to claim 7, characterized in that: The third heat exchange device is provided with a third liquid inlet, a third liquid outlet, a fourth liquid inlet and a fourth liquid outlet; The third liquid inlet is communicated with the first liquid outlet of the first heat exchange device; the third liquid outlet is communicated with the third black water inlet of the black water circulation device; the fourth liquid inlet is communicated with the second liquid outlet of the second heat exchange device; the fourth liquid outlet is communicated with the fourth heat exchange device; A water outlet is provided between the fourth liquid outlet and the fourth heat exchange device.

10. The black water purification system according to claim 9, characterized in that: The fourth heat exchange device is provided with a fifth liquid inlet, a fifth liquid outlet, a cold medium inlet and a hot medium outlet; The fifth liquid inlet is connected to the fourth liquid outlet of the third heat exchange device; the fifth liquid outlet is connected to the second liquid inlet of the second heat exchange device; and the cold medium inlet is connected to a cooling device.

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