Organic wastewater energy-saving treatment system and method

Abstract

According to the organic wastewater energy-saving treatment system and method, in the system and method, organic matter in organic wastewater can be greatly reduced through oil separation treatment of the reservoir and filtration and coalescence separation treatment of the filtration coalescence device, and the purpose of recycling the organic matter is achieved; through multi-effect evaporation of the I-effect falling film evaporator, the II-effect falling film evaporator and the forced circulation evaporator, generated steam is recycled through the MVR compressor, cyclic utilization of secondary steam energy is achieved, and energy consumption is reduced; and the wastewater can be recycled through a multi-effect evaporation and resin adsorption treatment mode, and the recovery rate reaches 96%. The steam consumption for wastewater treatment can be reduced by 0.90 t / m < 3 >.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and relates to an energy-saving treatment system and method for organic wastewater. Background Art

[0002] Organic wastewater usually contains a large amount of organic matter such as anthraquinone, aromatic hydrocarbons, trioctyl phosphate, and salts such as aluminum oxide and potassium carbonate. Organic wastewater needs to be treated before it can be discharged or recycled.

[0003] At present, the treatment method for organic wastewater is usually direct incineration, which results in the organic matter in the organic wastewater cannot be recovered. At the same time, for organic wastewater with insufficient calorific value, it is necessary to use fuel to increase the calorific value before mixing and burning, resulting in energy waste. Summary of the invention

[0004] The purpose of the present invention is to provide an energy-saving treatment system and method for organic wastewater, so as to solve the problem of energy waste in the existing incineration treatment of organic wastewater.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present application provides an energy-saving treatment system for organic wastewater, comprising a water storage tank, a filtering and coalescing device, a first plate heat exchanger, a shell and tube heat exchanger, a first-effect falling film evaporator, a second-effect falling film evaporator and a forced circulation evaporator which are sequentially connected; the first-effect falling film evaporator, the second-effect falling film evaporator and the forced circulation evaporator are respectively connected to an MVR compressor, and the shell and tube heat exchanger, the first-effect falling film evaporator, the second-effect falling film evaporator and the forced circulation evaporator are also respectively connected to a condensate tank; the condensate tank is sequentially connected to a second plate heat exchanger and a resin adsorption device after heat exchange with the first plate heat exchanger.

[0006] Preferably, the filtering and coalescing device comprises a homogenizing tank, a filter and a coalescing separator connected to each other, the homogenizing tank is connected to the water reservoir, and the coalescing separator is connected to the first plate heat exchanger.

[0007] Preferably, the resin adsorption device includes three adsorption tanks, which adopt a two-in-series and one-in-standby operation mode.

[0008] The present application provides an energy-saving treatment method for organic wastewater, comprising: After separation of oil, homogenization, filtration and coalescence, the organic wastewater is preheated to 100-105℃ through two-stage heat exchange in the first plate heat exchanger and the shell and tube heat exchanger; The preheated organic wastewater is evaporated through the first effect falling film evaporator to separate secondary steam and wastewater, part of the wastewater is circulated to the first effect falling film evaporator for re-evaporation, and the other part of the wastewater enters the second effect falling film evaporator; The wastewater is evaporated by the II-effect falling film evaporator to separate secondary steam and secondary wastewater; The secondary wastewater is evaporated in a forced circulation evaporator to separate secondary steam and concentrated liquid, and the concentrated liquid is sent to an incinerator for incineration; The condensate generated by the heat exchange of the tube heat exchanger, the first effect falling film evaporator, the second effect falling film evaporator and the forced circulation evaporator exchanges heat with the first plate heat exchanger, then exchanges heat with the second plate heat exchanger, and is discharged into the resin adsorption device; The secondary steam evaporated from the I-effect falling film evaporator, the II-effect falling film evaporator and the forced circulation evaporator is compressed by the MVR compressor to increase the temperature and pressure, and then used as a heat source to provide heat for the I-effect falling film evaporator and the forced circulation evaporator.

[0009] Preferably, the secondary steam is heated to 118° C. and its pressure is increased to 0.15 MPa. Preferably, the heating temperature of the first-effect falling film evaporator is 118° C., the evaporation temperature is 109° C., and the separation factor is 0.35.

[0010] Preferably, the heating temperature of the II-effect falling film evaporator is 109° C., the evaporation temperature is 98° C., and the separation factor is 0.45.

[0011] Preferably, the heating temperature of the forced circulation evaporator is 118° C., the evaporation temperature is 98° C., and the separation factor is 0.48.

[0012] Preferably, in the organic wastewater, the phosphate content is 20-60 g / L, the anthraquinone content is ≤10 g / L, the aluminum chloride powder content is ≤0.15 g / L, the COD content is 2000-5000 mg / L, and the ammonia nitrogen content is ≤10 mg / L.

[0013] The present invention has the following beneficial effects: (1) Through the oil separation treatment of the water storage tank, the filtration and agglomeration separation treatment of the filtration and agglomeration device, the organic matter in the organic wastewater can be greatly reduced, achieving the purpose of recovering the organic matter.

[0014] (2) The steam generated by the multi-effect evaporation of the first-effect falling film evaporator, the second-effect falling film evaporator and the forced circulation evaporator is recovered through the MVR compressor to achieve the recycling of secondary steam energy and save energy consumption.

[0015] (3) Wastewater can be recycled through multi-effect evaporation and resin adsorption, with a recovery rate of up to 96%.

[0016] (4) The steam consumption for wastewater treatment in this application can be reduced by 0.90t / m 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of an energy-saving treatment system for organic wastewater provided in an embodiment of the present application; Symbols represent: 1-water storage tank, 2-filtration and coalescence device, 3-first plate heat exchanger, 4-tube heat exchanger, 5-Ⅰ effect falling film evaporator, 6-Ⅱ effect falling film evaporator, 7-forced circulation evaporator, 8-MVR compressor, 9-condensate tank, 10-second plate heat exchanger, 11-resin adsorption device. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further explained and illustrated by means of specific embodiments below.

[0019] Example 1 The embodiment of the present application provides an energy-saving treatment system for organic wastewater, which includes a water storage tank 1, a filtering and coalescing device 2, a first plate heat exchanger 3, a shell and tube heat exchanger 4, an effect I falling film evaporator 5, an effect II falling film evaporator 6 and a forced circulation evaporator 7 which are connected in sequence, and the effect I falling film evaporator 5, the effect II falling film evaporator 6 and the forced circulation evaporator 7 are respectively connected to an MVR compressor 8, and the shell and tube heat exchanger 4, the effect I falling film evaporator 5, the effect II falling film evaporator 6 and the forced circulation evaporator 7 are also respectively connected to a condensate tank 9; the condensate tank 9 is sequentially connected to a second plate heat exchanger 10 and a resin adsorption device 11 after heat exchange with the first plate heat exchanger 3, as shown in the attached Figure 1 shown.

[0020] Specifically, the water reservoir 1 is a component for separating organic matter and wastewater from the organic wastewater. In the water reservoir 1, the organic wastewater uses the density difference and gravity difference between the organic matter and the wastewater to separate the suspended oil droplets in the wastewater, the separated organic matter is recycled, and the separated wastewater is discharged into the filtering and coalescing device 2. In the present application, the oil content in the organic wastewater is first reduced by oil separation treatment in the water reservoir 1, and then filtered and coalesced to prevent the viscous oily organic matter from blocking the filtering and coalescing device 2.

[0021] In the filtering and coalescing device 2, the wastewater is sequentially homogenized, filtered and coalesced and separated, and the treated wastewater is discharged into the first plate heat exchanger 3. The filtering and coalescing device 2 in the embodiment of the present application comprises a homogenizing tank, a filter and a coalescing separator connected to each other, wherein the homogenizing tank is connected to the water reservoir 1, and the coalescing separator is connected to the first plate heat exchanger 3. After the wastewater is homogenized in the homogenizing tank, it is discharged into the filter, and the solid suspended matter in the wastewater is filtered out by the filter bag in the filter. After filtering the solid suspended matter, the wastewater is discharged into the coalescing separator for coalescing and separation treatment. The coalescing separator contains a coalescing filter element and a separation filter element, which utilizes the different affinities of the polarity of the two filter element materials to different liquids to capture and separate small oil droplets in the wastewater, thereby achieving further separation of organic matter and wastewater and reducing the concentration of organic matter in organic wastewater.

[0022] The wastewater separated by the coalescing separator is pressurized by the wastewater pump and discharged into the first plate heat exchanger 3. The temperature is raised to 95-100°C by heat exchange with the first plate heat exchanger 3 to achieve preliminary preheating of the wastewater. The preliminarily preheated wastewater is discharged into the tube heat exchanger 4. The temperature is raised to 100-105°C by heat exchange with the tube heat exchanger 4. The preheated wastewater is discharged into the first effect falling film evaporator 5 to achieve further preheating of the wastewater. The condensate generated during the preheating process of the wastewater by the tube heat exchanger 4 is discharged into the condensate tank 9. The non-condensable gases such as aromatic hydrocarbons and oxygen overflow from the tube heat exchanger 4 and are sent to the boiler for incineration to achieve energy recycling.

[0023] In the I-effect falling film evaporator 5, primary steam is introduced into the outer tube of the I-effect falling film evaporator 5, and the primary steam can heat the wastewater in the inner tube by heat exchange, thereby heating the wastewater. Among them, the heating temperature of the wastewater by the primary steam is 118°C, and the evaporation temperature of the wastewater is 109°C. Under the heat exchange of the primary steam, the wastewater boils, and the evaporated secondary steam will carry part of the droplets into the falling film evaporation chamber in the I-effect falling film evaporator 5, and then the falling film evaporation chamber will separate the secondary steam and the entrained droplets. After the droplets are mixed with the unevaporated wastewater, part of the wastewater is sent back to the top of the I-effect falling film evaporator 5 for reflux evaporation; the other part of the wastewater enters the II-effect falling film evaporator 6 from the bottom of the I-effect falling film evaporator 5. The primary steam condenses to form condensate during the heat exchange process of the wastewater, and the condensate is discharged into the condensate tank 9. Part of the secondary steam is discharged into the II effect falling film evaporator 6 as a heat source for heat exchange of the II effect falling film evaporator 6, and the other part is extracted by the MVR compressor 8.

[0024] In the embodiment of the present application, the heat load of the first effect falling film evaporator 5 is 6679kW, the heater type is a tubular heater, and the separator volume is 8.7m 3 , the separator separation factor is 0.35.

[0025] The II-effect falling film evaporator 6 is a component for further evaporating water vapor in the wastewater, wherein the heating temperature of the II-effect falling film evaporator 6 is 109°C and the evaporation temperature of the wastewater is 98°C. The process and principle of the II-effect falling film evaporator 6 on the wastewater are the same as those of the I-effect falling film evaporator 5, and will not be repeated here. Similar to the I-effect falling film evaporator 5, the II-effect falling film evaporator 6 discharges the condensate generated during the heat exchange of the wastewater into the condensate tank 9, and the secondary steam generated is extracted by the MVR compressor 8.

[0026] In the embodiment of the present application, the heat load of the II-effect falling film evaporator 6 is 6066kW, the heater type is a tubular heater, and the separator volume is 13.2m 3 , the separator separation factor is 0.45.

[0027] The wastewater after evaporation treatment by the II-effect falling film evaporator 6 is discharged into the forced circulation evaporator 7. After the temperature is raised to 118°C by the forced circulation evaporator 7, the wastewater is further evaporated and concentrated to form secondary steam and concentrated liquid. Among them, the evaporation temperature of the wastewater is 98°C. The concentrated liquid formed by evaporation enters the concentrated liquid tank and is transported to the waste liquid incinerator for incineration treatment by a tank truck. The condensate generated during the evaporation treatment of the wastewater by the forced circulation evaporator 7 is also discharged into the condensate tank 9, and the secondary steam generated is pumped away by the MVR compressor 8.

[0028] In the embodiment of the present application, the heat load of the forced circulation evaporator 7 is 6372 kW, the heater type is a tubular heater, and the separator volume is 13.2 m 3 , the separator separation factor is 0.48.

[0029] In the MVR compressor 8, the MVR compressor 8 uses electric drive to compress the secondary steam to increase the temperature, pressure and thermal enthalpy of the secondary steam and improve the steam quality. In the embodiment of the present application, the MVR compressor 8 increases the temperature of the secondary steam to 118°C and the pressure to 0.15MPa. The secondary steam after heating and pressurization is discharged into the I effect falling film evaporator 5 and the forced circulation evaporator 7 respectively to participate in heat exchange. As a result, a circulation loop of secondary steam is formed between the I effect falling film evaporator 5, the II effect falling film evaporator 6, the forced circulation evaporator 7 and the MVR compressor 8.

[0030] In the embodiment of the present application, except for the start-up, only a small amount of primary steam is used in the entire evaporation process of the wastewater, and the remaining steam used is all secondary steam recovered by the MVR compressor 8, which greatly reduces the energy input and realizes the recycling of secondary steam, saving costs.

[0031] The condensate generated during the heat exchange and evaporation of wastewater by the tube heat exchanger 4, the first effect falling film evaporator 5, the second effect falling film evaporator 6 and the forced circulation evaporator 7 is discharged into the condensate tank 9, and then enters the first plate heat exchanger 3 after being pressurized by the condensate pump to participate in the heat exchange and preheating treatment of the wastewater. The condensate after heat exchange is discharged into the resin adsorption device 11 after heat exchange treatment by the second plate heat exchanger 10.

[0032] In the resin adsorption device 11, after the resin adsorption device 11 adsorbs the condensate, it is discharged into the reclaimed water circulation system. The resin adsorption device 11 in the embodiment of the present application includes three adsorption tanks, which adopt a two-in-one standby operation mode. The two-in-one standby operation mode is a method of first using adsorption tank A and adsorption tank B in series for adsorption, wherein adsorption tank A is a primary adsorption tank and adsorption tank B is a secondary adsorption tank. When the COD of the effluent at the adsorption outlet of adsorption tank A exceeds the standard, it is switched to a mode in which adsorption tank B and adsorption tank C are connected in series. At this time, adsorption tank B is a primary adsorption tank and adsorption tank C is a secondary adsorption tank. Adsorption tank A is used for steam desorption treatment and then used as a standby, and continuous adsorption treatment is achieved in this cycle. In the embodiment of the present application, the COD standard of the effluent at the adsorption outlet of the adsorption tank is <60 mg / L. The effluent produced during the adsorption process of the resin adsorption device 11 enters the park and is used as circulating water replenishment to improve utilization.

[0033] Example 2 The present invention provides an energy-saving method for treating organic wastewater, which comprises: S01: After separation by oil separation, homogenization, filtration and agglomeration, the organic wastewater is preheated to 100-105℃ through two-stage heat exchange in the first plate heat exchanger and the shell and tube heat exchanger.

[0034] The organic wastewater in the embodiment of the present application includes 95.89% water, 1.61% organic matter and 2.5% other salts by mass fraction, wherein the organic matter includes 0.83% anthraquinone, 0.17% aromatic hydrocarbons, 0.61% trioctyl phosphate, and other salts include aluminum oxide, potassium carbonate and others. The water quality indicators of the organic wastewater are: pH 6-9, phosphate content 20-60g / L, anthraquinone content ≤10g / L, aluminum chloride powder content ≤0.15g / L, COD content 2000-5000mg / L, ammonia nitrogen content ≤10mg / L.

[0035] In the reservoir 1, the organic wastewater uses the density difference and gravity difference between organic matter and wastewater to separate the suspended oil droplets in the wastewater. The separated organic matter is recycled and reused, and the separated wastewater is discharged into the filtering and coalescing device 2. In the filtering and coalescing device 2, after the wastewater is homogenized, the solid suspended matter in the wastewater is filtered out by the filter bag in the filter. Then, the small oil droplets in the wastewater are captured and separated by the different affinity of the polarity of the two filter element materials in the coalescing separator to different liquids, so as to further separate the organic matter and wastewater and reduce the concentration of organic matter in the organic wastewater. The treated wastewater is discharged into the first plate heat exchanger 3.

[0036] The wastewater separated by the filtration and coalescence device 2 is pressurized by the wastewater pump and discharged into the first plate heat exchanger 3. The temperature is raised to 95-100°C by heat exchange with the first plate heat exchanger 3 to achieve preliminary preheating of the wastewater. The preliminarily preheated wastewater is discharged into the tube heat exchanger 4. The temperature is raised to 100-105°C by heat exchange with the tube heat exchanger 4, and the preheated wastewater is discharged into the first effect falling film evaporator 5. The condensate generated during the preheating process of the wastewater by the tube heat exchanger 4 is discharged into the condensate tank 9, and the non-condensable gases such as aromatic hydrocarbons and oxygen overflow from the tube heat exchanger 4 and are sent to the boiler for incineration to achieve energy recycling.

[0037] S02: The preheated organic wastewater is evaporated through the I-effect falling film evaporator to separate secondary steam and wastewater, part of the wastewater is circulated to the I-effect falling film evaporator for re-evaporation, and the other part of the wastewater enters the II-effect falling film evaporator.

[0038] The primary steam is introduced into the outer tube of the I-effect falling film evaporator 5, and the primary steam can heat the wastewater in the inner tube by heat exchange, wherein the heating temperature of the wastewater by the primary steam is 118°C, and the evaporation temperature of the wastewater is 109°C. Under the heat exchange of the primary steam, the wastewater boils, and the evaporated secondary steam will carry part of the droplets into the falling film evaporation chamber in the I-effect falling film evaporator 5, and then the falling film evaporation chamber will separate the secondary steam and the entrained droplets. After the droplets are mixed with the unevaporated wastewater, part of the wastewater is sent back to the top of the I-effect falling film evaporator 5 for reflux evaporation; the other part of the wastewater enters the II-effect falling film evaporator 6 from the bottom of the I-effect falling film evaporator 5. The primary steam condenses to form condensate during the heat exchange process of the wastewater, and the condensate is discharged into the condensate tank 9. The secondary steam part is discharged into the II-effect falling film evaporator 6 as the heat exchange heat source of the II-effect falling film evaporator 6, and the other part is extracted by the MVR compressor 8.

[0039] S03: The wastewater is evaporated through the II-effect falling film evaporator to separate secondary steam and secondary wastewater.

[0040] After the wastewater enters the II effect falling film evaporator 6, the secondary steam discharged from the I effect falling film evaporator 5 exchanges heat with the wastewater in the II effect falling film evaporator 6, wherein the heating temperature in the II effect falling film evaporator 6 is 109°C, the evaporation temperature is 98°C, and the separation factor is 0.45. After the heat exchange, the wastewater boils, and the evaporated secondary steam will carry part of the droplets into the falling film evaporation chamber in the II effect falling film evaporator 6, and then the falling film evaporation chamber will separate the secondary steam and the entrained droplets. The droplets are mixed with the unevaporated wastewater to form secondary wastewater, and part of the secondary wastewater is sent back to the top of the II effect falling film evaporator 6 for reflux evaporation; the other part of the secondary wastewater enters the forced circulation evaporator 7 from the bottom of the II effect falling film evaporator 6. The secondary steam discharged from the I effect falling film evaporator 5 condenses to form condensate during the heat exchange process with the wastewater, and the condensate is discharged into the condensate tank 9. The secondary steam is pumped away by the MVR compressor 8.

[0041] S04: The secondary wastewater is evaporated in a forced circulation evaporator to separate secondary steam and concentrated liquid, and the concentrated liquid is sent to an incinerator for incineration.

[0042] After the secondary wastewater is heated to 118°C by the forced circulation evaporator 7, it continues to evaporate and concentrate the wastewater to form secondary steam and concentrated liquid. The evaporation temperature of the wastewater is 98°C. The concentrated liquid formed by evaporation enters the concentrated liquid tank and is transported to the waste liquid incinerator for incineration by a tank truck. The condensate generated during the evaporation of the wastewater by the forced circulation evaporator 7 is also discharged into the condensate tank 9, and the secondary steam generated is pumped away by the MVR compressor 8.

[0043] S05: The condensate generated by the heat exchange of the shell and tube heat exchanger, the first effect falling film evaporator, the second effect falling film evaporator and the forced circulation evaporator is heat exchanged with the first plate heat exchanger, and then with the second plate heat exchanger to be discharged into the resin adsorption device.

[0044] The condensate generated during the heat exchange and evaporation of wastewater by the shell and tube heat exchanger 4, the first effect falling film evaporator 5, the second effect falling film evaporator 6 and the forced circulation evaporator 7 is discharged into the condensate tank 9, and then enters the first plate heat exchanger 3 after being pressurized by the condensate pump to participate in the heat exchange and preheating treatment of the wastewater. The condensate after heat exchange is discharged into the resin adsorption device 11 after heat exchange treatment by the second plate heat exchanger 10. The resin adsorption device 11 adsorbs the condensate and then discharges it into the reclaimed water circulation system. Among them, the water quality indicators of the effluent after treatment by the resin adsorption device 11 are: pH ≥ 6.5, COD content ≤ 60ppm, BOD content ≤ 0.3ppm, and ammonia nitrogen content ≤ 5ppm.

[0045] S06: The secondary steam evaporated from the I-effect falling film evaporator, the II-effect falling film evaporator and the forced circulation evaporator is compressed by the MVR compressor to increase the temperature and pressure, and then used as a heat source to provide heat for the I-effect falling film evaporator and the forced circulation evaporator.

[0046] In the MVR compressor 8, the MVR compressor 8 uses electric drive to compress the secondary steam evaporated from the first effect falling film evaporator, the second effect falling film evaporator and the forced circulation evaporator to increase the temperature, pressure and thermal enthalpy of the secondary steam. The secondary steam after temperature increase and pressurization is discharged into the first effect falling film evaporator 5 and the forced circulation evaporator 7 respectively to participate in heat exchange. Thus, a circulation loop of secondary steam is formed between the first effect falling film evaporator 5, the second effect falling film evaporator 6, the forced circulation evaporator 7 and the MVR compressor 8.

[0047] In the present application example, the steam consumption used to treat organic wastewater is reduced by 0.90t / m 3 . The organic wastewater treatment capacity is 15m 3 / h, and the annual operating time is 8000h. The annual steam saving is 108496t, and the electricity consumption increases by 3.5421 million kWh. Compared with the conventional wastewater treatment device, it saves 85.26kgce of energy per ton of wastewater.

[0048] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An energy-saving treatment system for organic wastewater, characterized in that: The invention comprises a water storage tank (1), a filtering and coalescing device (2), a first plate heat exchanger (3), a shell and tube heat exchanger (4), a first effect falling film evaporator (5), a second effect falling film evaporator (6) and a forced circulation evaporator (7) which are connected in sequence; the first effect falling film evaporator (5), the second effect falling film evaporator (6) and the forced circulation evaporator (7) are respectively connected to an MVR compressor (8), and the shell and tube heat exchanger (4), the first effect falling film evaporator (5), the second effect falling film evaporator (6) and the forced circulation evaporator (7) are also respectively connected to a condensate tank (9); the condensate tank (9) is connected to a second plate heat exchanger (10) and a resin adsorption device (11) in sequence after heat exchange with the first plate heat exchanger (3).

2. The energy-saving treatment system for organic wastewater according to claim 1 is characterized in that: The filtering and coalescing device (2) comprises a homogenizing tank, a filter and a coalescing separator which are connected to each other, the homogenizing tank being connected to the water reservoir (1), and the coalescing separator being connected to the first plate heat exchanger (3).

3. The organic wastewater energy-saving treatment system according to claim 1 is characterized in that: The resin adsorption device (11) comprises three adsorption tanks, which adopt a two-in-series and one-in-standby operation mode.

4. An energy-saving treatment method for organic wastewater, characterized in that: include: After separation of oil, homogenization, filtration and coalescence, the organic wastewater is preheated to 100-105℃ through two-stage heat exchange in the first plate heat exchanger and the shell and tube heat exchanger; The preheated organic wastewater is evaporated through the first effect falling film evaporator to separate secondary steam and wastewater, part of the wastewater is circulated to the first effect falling film evaporator for re-evaporation, and the other part of the wastewater enters the second effect falling film evaporator; The wastewater is evaporated by the II-effect falling film evaporator to separate secondary steam and secondary wastewater; The secondary wastewater is evaporated in a forced circulation evaporator to separate secondary steam and concentrated liquid, and the concentrated liquid is sent to an incinerator for incineration; The condensate generated by the heat exchange of the tube heat exchanger, the first effect falling film evaporator, the second effect falling film evaporator and the forced circulation evaporator exchanges heat with the first plate heat exchanger, then exchanges heat with the second plate heat exchanger, and is discharged into the resin adsorption device; The secondary steam evaporated from the I-effect falling film evaporator, the II-effect falling film evaporator and the forced circulation evaporator is compressed by the MVR compressor to increase the temperature and pressure, and then used as a heat source to provide heat for the I-effect falling film evaporator and the forced circulation evaporator.

5. The energy-saving treatment method for organic wastewater according to claim 4, characterized in that: The secondary steam is heated to 118° C. and its pressure is increased to 0.15 MPa.

6. The energy-saving treatment method for organic wastewater according to claim 4 is characterized in that: The heating temperature of the first effect falling film evaporator is 118°C, the evaporation temperature is 109°C, and the separation factor is 0.

35.

7. The energy-saving treatment method for organic wastewater according to claim 4, characterized in that: The heating temperature of the II-effect falling film evaporator is 109° C., the evaporation temperature is 98° C., and the separation factor is 0.

45.

8. The energy-saving treatment method for organic wastewater according to claim 4, characterized in that: The heating temperature of the forced circulation evaporator is 118° C., the evaporation temperature is 98° C., and the separation factor is 0.

48.

9. The energy-saving treatment method for organic wastewater according to claim 4, characterized in that: In the organic wastewater, the phosphate content is 20-60 g / L, the anthraquinone content is ≤10 g / L, the aluminum chloride powder content is ≤0.15 g / L, the COD content is 2000-5000 mg / L, and the ammonia nitrogen content is ≤10 mg / L.

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