System and method for treating salt-containing organic wastewater

Abstract

The application discloses a treatment system and method for salt-containing organic wastewater. The treatment system for the salt-containing organic wastewater comprises a one-effect evaporation system, a two-effect evaporation system and a three-effect evaporation system. The salt-containing organic wastewater at normal temperature is first preheated by an organic wastewater preheater before entering the one-effect evaporator. In the one-effect evaporator, the gas-water mixture is subjected to flash evaporation in a one-effect gas-liquid separation tank, the gas phase enters the two-effect evaporator for continuous treatment. The gas phase generated in the two-effect evaporation system enters the three-effect evaporator for continuous treatment. The gas phase generated in the three-effect gas-liquid separation tank enters the three-effect evaporation condenser, and the high-salinity concentrated liquid after concentration enters a centrifugal machine for treatment. During the evaporation process of the organic wastewater, the light phase and the heavy phase organic matter can be effectively separated and recovered after the machine matter is concentrated, and no organic colloid wrapping material is formed, so that the adhesion and scaling phenomenon of the organic colloid is avoided, and the smooth and efficient operation of production can be ensured.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment technology, and specifically relates to a treatment system and method for saline organic wastewater. Background Technology

[0002] Currently, various industrial production sectors, including chemical, biological, pharmaceutical, petrochemical, papermaking, and food processing, discharge large quantities of saline, high-COD (Chemical Oxygen Demand) organic wastewater. This wastewater not only contains high concentrations of organic pollutants but also large amounts of calcium, magnesium, sodium, chloride, sulfate, and nitrate ions. Treating saline wastewater is challenging and requires sophisticated equipment and processes.

[0003] The most common treatment process currently involves evaporation and concentration to crystallize and separate salts from the wastewater. The resulting condensate has a high COD content and can be further treated to meet discharge standards. During evaporation and concentration, most of the high-concentration organic matter forms a supersaturated solution as the water content decreases, thus precipitating out. Organic matter less dense than water, such as oils and fatty acids, becomes a lighter phase and floats on the surface; organic matter denser than water forms a suspension in the concentrate. The mixture and encapsulation of various organic substances form hydrophobic colloidal substances, which easily adhere to the inner walls of evaporation equipment, forming scale and greatly reducing the operating efficiency of the evaporation equipment. They also cause blockages on the inner walls of the heat exchange tubes of the evaporator, reducing the heating area, decreasing the evaporation rate of wastewater, and increasing steam consumption. The high boiling point of organic colloids prevents them from entering the evaporation condensate system with the gas phase, instead remaining in the by-product salts, increasing the impurity content of the by-products and reducing their quality and added value. Higher system complexity and increased concentration of organic matter can lead to fluctuations in evaporation rates, and even cause explosive boiling. Although explosive boiling is short-lived, it generates mist that carries salts into the gas phase, which then enters the condensate, making subsequent condensate treatment difficult. In severe cases, it can inhibit the growth and reproduction of bacteria in the biological system, paralyzing the wastewater biological treatment system. Furthermore, the high proportion of mother liquor in the evaporation system, along with its high COD and salt content, makes it difficult to treat effectively. Returning it to the wastewater inlet will inevitably create a vicious cycle, increasing the treatment burden of the entire system. The organic components in organic wastewater are mostly main products or byproducts of the treatment process. Current processes do not recover these organic components, resulting in waste of organic products, environmental pollution, and increased production costs. Furthermore, current processes have low levels of automation, poor accuracy, and high labor intensity. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a treatment system and method for saline organic wastewater, so as to avoid the adhesion and scaling of organic colloids, prevent scaling and clogging of heat exchange equipment, and ensure stable and efficient operation of production.

[0005] To solve the above technical problems, according to one aspect of the present invention, a treatment system for saline organic wastewater is provided, comprising:

[0006] —An organic wastewater preheater is used to preheat saline organic wastewater at room temperature to a set temperature; the organic wastewater preheater is equipped with an organic wastewater hot material outlet end;

[0007] —A single-effect evaporator, which has a top port and a bottom port. The hot material outlet of the organic wastewater is connected to the top port of the single-effect evaporator. The bottom port of the single-effect evaporator is connected to the single-effect evaporation circulation pump through the inlet pipe of the single-effect evaporation circulation pump. The top port of the single-effect evaporator is connected to the single-effect evaporation circulation pump through the outlet pipe of the single-effect evaporation circulation pump. The shell side of the single-effect evaporator is connected to the heating steam feed pipe. Fresh heating steam is input through the heating steam feed pipe to heat the single-effect evaporator. The lower side wall of the single-effect evaporator is connected to the single-effect gas-liquid separator through the single-effect gas-liquid connecting pipe. The outlet pipe of the single-effect evaporation circulation pump is connected to the single-effect discharge filter pre-pipe. The single-effect discharge filter pre-pipe is connected to the inlet of the single-effect precision filter. The outlet of the single-effect precision filter is connected to the second-effect gas-liquid separator through the single-effect discharge filter post-pipe.

[0008] —A first-effect gas-liquid separator, with a first-effect oil phase discharge collection funnel installed in the middle of the first-effect gas-liquid separator. The first-effect oil phase discharge collection funnel is connected to the first-effect oil-water separator through the first-effect oil-water discharge pipe. The top of the first-effect gas-liquid separator is connected to the gas phase inlet of the second-effect evaporator through the first-effect evaporation gas phase pipe.

[0009] —A single-effect oil-water separator, which includes a single-effect oil-water liquid seal pipe and a single-effect oil-water separator heating steam distributor; the single-effect oil-water discharge pipe is connected to the top of the single-effect oil-water liquid seal pipe, and the single-effect oil-water separator heating steam distributor is connected to the single-effect oil-water separator heating steam main pipe through a single-effect oil-water separator heating steam branch pipe; the side wall of the single-effect oil-water separator is connected to the oil phase recovery section through a single-effect oil phase discharge pipe;

[0010] —A double-effect evaporator, which has a top port and a bottom port. The bottom port of the double-effect evaporator is connected to the double-effect evaporation circulation pump through the inlet pipe of the double-effect evaporation circulation pump, and the top port of the double-effect evaporator is connected to the double-effect evaporation circulation pump through the outlet pipe of the double-effect evaporation circulation pump. The lower side wall of the double-effect evaporator is connected to the double-effect gas-liquid separator through the double-effect gas-liquid connecting pipe. The outlet pipe of the double-effect evaporation circulation pump is connected to the double-effect discharge filter pre-pipe, which is connected to the inlet end of the double-effect precision filter. The outlet end of the double-effect precision filter is connected to the triple-effect gas-liquid separator through the double-effect discharge filter post-pipe.

[0011] —A double-effect gas-liquid separator, with a double-effect oil phase discharge collection funnel in the middle of the double-effect gas-liquid separator. The double-effect oil phase discharge collection funnel is connected to the double-effect oil-water separator through the double-effect oil-water discharge pipe. The top of the double-effect gas-liquid separator is connected to the gas phase inlet of the triple-effect evaporation heater through the double-effect evaporation gas phase pipe.

[0012] —A double-effect oil-water separator, which includes a double-effect oil-water liquid seal pipe and a double-effect oil-water separator heating steam distributor; the double-effect oil-water discharge pipe is connected to the top of the double-effect oil-water liquid seal pipe, and the double-effect oil-water separator heating steam distributor is connected to the double-effect oil-water separator heating steam main pipe through a double-effect oil-water separator heating steam branch pipe; the side wall of the double-effect oil-water separator is connected to the oil phase recovery section through a double-effect oil phase discharge pipe;

[0013] —A triple-effect evaporator heater; the top port of the triple-effect evaporator heater is connected to a triple-effect gas-liquid separator, and the bottom port of the triple-effect evaporator heater is connected to a triple-effect evaporator circulation pump.

[0014] —A triple-effect gas-liquid separator. The bottom port of the triple-effect gas-liquid separator is connected to the triple-effect evaporation circulation pump through a triple-effect evaporation circulation pipe. The top port of the triple-effect gas-liquid separator is connected to the triple-effect evaporation condenser through a triple-effect evaporation vapor phase pipe. The triple-effect evaporation circulation pipe is connected to the centrifuge through a triple-effect discharge pipe.

[0015] Furthermore, the bottom of the shell side of the first-effect evaporator is connected to the organic wastewater preheater via a first-effect condensate pipe.

[0016] Furthermore, the bottom of the shell side of the second-effect evaporator is connected to the bottom of the shell side of the third-effect evaporator via a second-effect condensate pipe.

[0017] Furthermore, the pre-filter pipe of the first-effect discharge filter is connected to the inlet end of the first-effect standby filter, and the outlet end of the first-effect standby filter is connected to the second-effect gas-liquid separator.

[0018] Furthermore, the pre-filter pipe of the second-effect discharge filter is connected to the inlet end of the second-effect standby filter, and the outlet end of the second-effect standby filter is connected to the third-effect gas-liquid separator.

[0019] Furthermore, the bottom port of the first-effect gas-liquid separator is connected to the inlet pipe of the first-effect evaporation circulation pump through the liquid phase circulation inclined pipe of the first-effect gas-liquid separator; the bottom port of the second-effect gas-liquid separator is connected to the inlet pipe of the second-effect evaporation circulation pump through the liquid phase circulation inclined pipe of the second-effect gas-liquid separator.

[0020] Furthermore, the bottom of the first-effect oil-water separator is connected to the inlet pipe of the first-effect evaporation circulation pump via the water phase recovery pipe of the first-effect oil-water separator; the bottom of the second-effect oil-water separator is connected to the inlet pipe of the second-effect evaporation circulation pump via the water phase recovery pipe of the second-effect oil-water separator.

[0021] Furthermore, a heating steam control valve for the first-effect oil-water separator is installed on the heating steam branch pipe, and an oil phase temperature sensor for the first-effect oil-water separator is installed on the first-effect oil-water separator. The oil phase temperature sensor for the first-effect oil-water separator is connected to the heating steam control valve for the first-effect oil-water separator.

[0022] Furthermore, a heating steam control valve for the second-effect oil-water separator is installed on the heating steam branch pipe, and a second-effect oil phase temperature sensor is installed on the second-effect oil-water separator, which is connected to the heating steam control valve for the second-effect oil-water separator.

[0023] According to another aspect of the present invention, a method for treating saline organic wastewater is provided. Using the treatment system described above, the saline organic wastewater at room temperature passes through an organic wastewater preheater before entering the first-effect evaporator, raising its temperature to a set value, and then enters the first-effect evaporator from the top. Fresh heating steam is used to heat the first-effect evaporator. In the first-effect evaporator, a first-effect evaporation circulation pump is used to force-circulate and heat the wastewater. The gas-water mixture enters the first-effect gas-liquid separator through the first-effect gas-liquid connecting pipe for flash evaporation. The oil-water mixture is collected by the first-effect oil phase discharge collection funnel and flows into the first-effect oil-water separator for further sedimentation and stratification. The oil phase flows out through the first-effect oil phase discharge pipe, and the gas phase generated in the first-effect gas-liquid separator enters the second-effect evaporator through the first-effect evaporation gas phase pipe for further treatment.

[0024] In the double-effect evaporation system, the concentrated liquid from the first-effect evaporator enters the second-effect gas-liquid separator after passing through a precision filter. It is then subjected to forced circulation heating using a second-effect evaporation circulation pump. The gas-liquid mixture enters the second-effect gas-liquid separator through the second-effect gas-liquid connecting pipe for flash evaporation. The oil-water mixture is collected by the second-effect oil phase discharge collection funnel and flows into the second-effect oil-water separator for further sedimentation and stratification. The oil phase flows out through the second-effect oil phase discharge pipe, and the gas phase generated in the second-effect gas-liquid separator enters the third-effect evaporator through the second-effect evaporation gas phase pipe for further processing.

[0025] In a triple-effect evaporation system, the concentrate from the double-effect evaporator enters the triple-effect gas-liquid separator after passing through a precision filter. The triple-effect evaporation circulation pump is used for forced circulation heating. The gas-liquid mixture enters the triple-effect gas-liquid separator for flash evaporation. The gas phase generated in the triple-effect gas-liquid separator enters the triple-effect evaporation condenser through the triple-effect evaporation gas phase pipe. The cooling medium of the triple-effect evaporation condenser is circulating cooling water. The concentrated high-salinity concentrate enters a centrifuge for processing.

[0026] Compared with the prior art, the present invention has the following technical effects:

[0027] (1) In this invention, during the evaporation of organic wastewater, after the organic matter is concentrated, both the light and heavy phases of organic matter are effectively separated and recovered, without forming organic colloidal coatings. This avoids the adhesion and scaling of organic colloids, preventing scaling and clogging of heat exchange equipment. It ensures stable and efficient production operation without the need for passive shutdowns or maintenance. Since there is no increase in fouling thermal resistance or decrease in heat transfer coefficient, it has the advantages of larger wastewater evaporation, lower steam consumption, and lower operating costs compared to existing processes.

[0028] (2) The COD content of the condensate produced by this invention is very low, avoiding boiling over and mist entrainment. The COD content of the condensate is so low that it can be directly discharged in compliance with standards or reused in the production system as production water, which greatly reduces production costs and wastewater discharge. Due to the early interception and separation of organic matter, the produced by-product salt is white in color, high in purity, and low in impurities, and has broad market prospects.

[0029] (3) The present invention utilizes the waste heat of the first-effect steam condensate to heat the low-temperature organic wastewater, saving the subsequent steam consumption; the second-effect steam condensate is used to heat the shell side of the third-effect evaporator, further recovering the waste heat of the second-effect steam condensate and saving the subsequent steam consumption.

[0030] (4) The proportion of mother liquor in the evaporation system of the present invention is low, less than 2%, and the COD and salt content are low, which can be well diluted in the system without increasing the operating burden of the entire system.

[0031] (5) The interlocking effect of the liquid level sensor, temperature sensor and automatic control valve is scientifically and rationally utilized to control key parameters, realizing the automated control of separation operation and greatly reducing the intensity of manual labor. Attached Figure Description

[0032] Figure 1 This is a flowchart of the treatment system and method for saline organic wastewater provided by the present invention.

[0033] In the diagram, 1-Organic wastewater cold feed pipe, 2-Organic wastewater preheater, 3-Organic wastewater hot feed pipe, 4-Organic wastewater temperature remote transmission instrument, 5-Organic wastewater feed flow meter, 6-First-effect evaporator, 7-Heating steam feed pipe, 8-Heating steam pressure remote transmission instrument, 9-First-effect condensate pipe, 10-First-effect condensate reuse pipe, 11-First-effect gas-liquid connecting pipe, 12-First-effect gas-liquid separator, 13-First-effect gas-liquid separator sight glass, 14-First-effect gas-liquid separator vacuum sensor, 15-First-effect gas-liquid separator temperature sensor, 16-First-effect gas-liquid separator liquid phase circulation inclined tube, 17-First-effect evaporation circulation pump inlet pipe, 18-First-effect evaporation circulation pump, 19-First-effect evaporation circulation pump outlet pressure gauge, 20-First-effect evaporation circulation flow meter. 21-First-Effect Oil Phase Discharge Collection Funnel, 22-First-Effect Oil-Water Discharge Pipe, 23-First-Effect Oil-Water Liquid Seal Pipe, 24-First-Effect Oil-Water Separator, 25-First-Effect Oil-Water Separator Vent Pipe, 26-First-Effect Oil-Water Separator Sight Glass, 27-First-Effect Oil Phase Discharge Pipe, 28-First-Effect Oil Phase Temperature Sensor, 29-First-Effect Oil-Water Separator Heating Steam Control Valve, 30-First-Effect Oil-Water Separator Heating Steam Distributor, 31-First-Effect Oil-Water Separator Heating Steam Branch Pipe, 32-First-Effect Oil-Water Separator Heating Steam Main Pipe, 33-First-Effect Oil-Water Separator Water Phase Recovery Pipe, 34-First-Effect Oil-Water Separator Liquid Level Remote Controller, 35-First-Effect Oil-Water Separator Water Phase Recovery Control Valve, 36-First-Effect Discharge Filter Pre-Pipe, 37-First-Effect Precision Filter Differential Pressure Gauge, 3 8-Precision filter for first-effect, 39-Standard filter for first-effect, 40-Differential pressure gauge for standby filter for first-effect, 41-Post-filter discharge pipe for first-effect, 42-Vacuum phase pipe for first-effect, 43-Second-effect evaporator, 44-Gas-liquid connecting pipe for second-effect, 45-Gas-liquid separator for second-effect, 46-Sight glass for second-effect, 47-Vacuum sensor for second-effect, 48-Temperature sensor for second-effect, 49-Liquid phase circulation inclined tube for second-effect, 50-Inlet pipe for second-effect, 51-Evaporator circulation pump for second-effect, 52-Outlet pressure gauge for second-effect, 53-Flow meter for second-effect, 54-Oil phase discharge collection funnel for second-effect, 55-Oil-water discharge pipe for second-effect, 56-Oil-water liquid seal pipe for second-effect, 57-Oil-water... 58-Double-effect oil-water separator vent pipe; 59-Double-effect oil-water separator sight glass; 60-Double-effect oil phase discharge pipe; 61-Double-effect oil phase temperature sensor; 62-Double-effect oil-water separator heating steam control valve; 63-Double-effect oil-water separator heating steam distributor; 64-Double-effect oil-water separator heating steam branch pipe; 65-Double-effect oil-water separator heating steam main pipe; 66-Double-effect oil-water separator water phase recovery pipe; 67-Double-effect oil-water separator liquid level remote control instrument; 68-Double-effect oil-water separator water phase recovery control valve; 69-Double-effect discharge filter pre-pipe; 70-Double-effect precision filter differential pressure gauge; 71-Double-effect precision filter; 72-Double-effect spare filter; 73-Double-effect spare filter differential pressure gauge; 74-Double-effect discharge filter post-pipe.75-Double-effect evaporator vapor phase pipe; 76-Triple-effect evaporator heater; 77-Double-effect condensate pipe; 78-Triple-effect evaporator circulating pump; 79-Triple-effect evaporator circulating pipe; 80-Process condensate reuse pipe; 81-Triple-effect discharge pipe; 82-Triple-effect discharge flow meter; 83-Triple-effect discharge control valve; 84-Triple-effect evaporator separator temperature display; 85-Triple-effect evaporator separator sight glass; 86-Triple-effect gas-liquid separator; 87-Triple-effect gas-liquid separator vacuum sensor; 88-Triple-effect evaporator vapor phase pipe; 89-Triple-effect evaporator condenser; 90-Triple-effect non-condensable gas; 91-Circulating water return pipe; 92-Circulating water supply pipe; 93-Process condensate reuse pipe. Detailed Implementation

[0034] This embodiment addresses the effective separation and recovery of liquid and solid organic matter precipitated during the evaporation and concentration process of organic wastewater containing ions such as calcium, magnesium, sodium, chloride, sulfate, and nitrate. The direct benefit is the ability to recover organic by-products into the production system, thus "turning waste into treasure."

[0035] The saline organic wastewater treatment system provided in this embodiment, such as Figure 1 As shown, it includes a single-effect evaporation system, a double-effect evaporation system, and a triple-effect evaporation system.

[0036] The single-effect evaporation system mainly consists of an organic wastewater preheater 2, a single-effect evaporator 6, a single-effect gas-liquid separator 12, and a single-effect oil-water separator 24.

[0037] The organic wastewater cooling pipe 1 is used to input saline organic wastewater into the system. The organic wastewater preheater 2 is equipped with an organic wastewater inlet and an organic wastewater hot material outlet, with the organic wastewater inlet connected to the organic wastewater cooling pipe 1. The organic wastewater preheater 2 is used to preheat the room-temperature saline organic wastewater to a set temperature.

[0038] The single-effect evaporator 6 has a top port and a bottom port. The organic wastewater hot material outlet of the organic wastewater preheater 2 is connected to the top port of the single-effect evaporator 6 through the organic wastewater hot material pipe 3. The preheated organic wastewater hot material is input into the single-effect evaporator 6 from the top port. The organic wastewater hot material pipe 3 is equipped with an organic wastewater temperature remote transmission instrument 4 and an organic wastewater feed flow meter 5.

[0039] The bottom of the first-effect evaporator 6 is connected to the organic wastewater preheater 2 via a first-effect condensate pipe 9. The steam condensate generated in the first-effect evaporator 6 first enters the organic wastewater preheater 2 for waste heat utilization, and then enters the condensate recycling system through the first-effect condensate recycling pipe 10.

[0040] The shell side of the first-effect evaporator 6 is connected to the heating steam feed pipe 7, through which fresh heating steam is input to heat the first-effect evaporator 6. A heating steam pressure remote transmission instrument 8 is installed on the heating steam feed pipe 7.

[0041] The bottom port of the first-effect evaporator 6 is connected to the first-effect evaporation circulation pump 18 via the inlet pipe 17, and the top port of the first-effect evaporator 6 is connected to the first-effect evaporation circulation pump 18 via the outlet pipe. A pressure gauge 19 and a flow meter 20 are installed on the outlet pipe of the first-effect evaporation circulation pump. The lower side wall of the first-effect evaporator 6 is connected to the first-effect gas-liquid separator 12 via a gas-liquid connecting pipe 11.

[0042] The wastewater is forcibly circulated and heated using the aforementioned single-effect evaporation circulation pump 18. The resulting gas-water mixture enters the single-effect gas-liquid separator 12 for flash evaporation.

[0043] The outlet pipe of the first-effect evaporation circulating pump is connected to the first-effect pre-filter pipe 36, which is connected to the inlet end of the first-effect precision filter 38. The outlet end of the first-effect precision filter 38 is connected to the second-effect gas-liquid separator 45 via the first-effect post-filter pipe 41. Additionally, the first-effect pre-filter pipe 36 is also connected to the inlet end of the first-effect standby filter 39, and the outlet end of the first-effect standby filter 39 is connected to the second-effect gas-liquid separator 45. A first-effect precision filter differential pressure gauge 37 is installed on the first-effect precision filter 38, and a first-effect standby filter differential pressure gauge 40 is installed on the first-effect standby filter 39.

[0044] The liquid from the first-effect evaporation must first pass through two precision filters. These two precision filters are one for backup and one for use, ensuring that production does not need to be interrupted during the cleaning of the filter cake. The differential pressure gauge of the precision filter is used to determine the resistance of the filter cake in the filter. The larger the amount of filter cake, the greater the differential pressure. When the differential pressure reaches the set value, the backup filter needs to be switched and the filtered filter cake is recycled to the front-end process. The organic wastewater from the first-effect evaporation after passing through the precision filter enters the second-effect gas-liquid separator 45.

[0045] A first-effect oil phase discharge collection funnel 21 is provided in the middle of the first-effect gas-liquid separator 12. The first-effect oil phase discharge collection funnel 21 is connected to the first-effect oil-water separator 24 through the first-effect oil-water discharge pipe 22.

[0046] The top of the first-effect gas-liquid separator 12 is connected to the gas phase inlet of the second-effect evaporator 43 via the first-effect evaporation gas phase pipe 42. The gas flashed out in the first-effect gas-liquid separator 12 enters the shell side of the second-effect evaporator 43 to continue heating the material. The bottom port of the first-effect gas-liquid separator 12 is connected to the inlet pipe 17 of the first-effect evaporation circulation pump via the first-effect gas-liquid separator liquid phase circulation inclined pipe 16. The unflashed liquid phase continues to circulate, heat, and concentrate.

[0047] The first-effect gas-liquid separator 12 is equipped with a sight glass 13, a vacuum sensor 14, and a temperature sensor 15. The outlet pipe of the first-effect evaporation circulation pump is equipped with an outlet pressure gauge 19 and a flow meter 20.

[0048] The first-effect oil-water separator 24 is equipped with a first-effect oil-water liquid seal pipe 23 and a first-effect oil-water separator heating steam distributor 30. The first-effect oil-water discharge pipe 22 is connected to the top of the first-effect oil-water liquid seal pipe 23, and the first-effect oil-water separator heating steam distributor 30 is connected to the first-effect oil-water separator heating steam main pipe 32 through the first-effect oil-water separator heating steam branch pipe 31; the side wall of the first-effect oil-water separator 24 is connected to the oil phase recovery section through the first-effect oil phase discharge pipe 27.

[0049] A heating steam control valve 29 for the first-effect oil-water separator is installed on the heating steam branch pipe 31, and an oil phase temperature sensor 28 for the first-effect oil-water separator 24 is installed on the first-effect oil-water separator 24. The temperature in the first-effect oil-water separator 24 can be controlled to be maintained at the set value through the interlocking action of the oil phase temperature sensor 28 and the heating steam control valve 29.

[0050] The bottom of the first-effect oil-water separator 24 is connected to the inlet pipe 17 of the first-effect evaporation circulation pump via the first-effect oil-water separator water phase recovery pipe 33 to continue circulating heating and concentration. The first-effect oil-water separator water phase recovery pipe 33 is equipped with a first-effect oil-water separator water phase recovery control valve 35, and a first-effect oil-water separator liquid level remote control instrument 34 is also provided.

[0051] The single-effect oil-water separator 24 is equipped with a single-effect oil-water separator vent pipe 25 and a single-effect oil-water separator sight glass 26.

[0052] The double-effect evaporation system mainly consists of a double-effect evaporator 42, a double-effect gas-liquid separator 45, and a double-effect oil-water separator 57.

[0053] The double-effect evaporator 43 has a top port and a bottom port. The bottom port of the double-effect evaporator 43 is connected to the double-effect evaporation circulation pump 51 through the inlet pipe 50 of the double-effect evaporation circulation pump, and the top port of the double-effect evaporator 43 is connected to the double-effect evaporation circulation pump 51 through the outlet pipe of the double-effect evaporation circulation pump. The lower side wall of the double-effect evaporator 43 is connected to the double-effect gas-liquid separator 45 through the double-effect gas-liquid connecting pipe 44.

[0054] The wastewater is further circulated and heated by the double-effect evaporation circulation pump 51. The gas-water mixture generated after heating enters the double-effect gas-liquid separator 45 for flash evaporation.

[0055] The bottom of the shell side of the second-effect evaporator 43 is connected to the bottom of the shell side of the third-effect evaporator 76 via a second-effect condensate pipe 77. The condensate from the second-effect evaporator 43 flows directly into the third-effect evaporator heater 76, which allows for further recovery of waste heat.

[0056] The top of the first-effect gas-liquid separator 12 is connected to the gas phase inlet of the second-effect evaporator 43 via the first-effect evaporation gas phase pipe 42. Unlike the first-effect evaporator 6, the second-effect evaporator 43 uses secondary exhaust steam generated from the first-effect evaporation as the heating medium, rather than fresh steam, so that the heat of the secondary exhaust steam can be fully utilized.

[0057] The outlet pipe of the second-effect evaporator circulating pump is connected to the pre-filter pipe 69 of the second-effect evaporator. The pre-filter pipe 69 is connected to the inlet end of the second-effect precision filter 71. The outlet end of the second-effect precision filter 71 is connected to the third-effect gas-liquid separator 76 via the post-filter pipe 74. Additionally, the pre-filter pipe 69 is also connected to the inlet end of the second-effect standby filter 72. The outlet end of the standby filter 72 is connected to the third-effect gas-liquid separator 71. A differential pressure gauge 70 is installed on the second-effect precision filter 71, and a differential pressure gauge 73 is installed on the standby filter 72.

[0058] The liquid from the second-effect evaporation also needs to pass through two precision filters, one for backup and one for use. After passing through the precision filters, the organic wastewater from the second-effect evaporation enters the third-effect gas-liquid separator 71.

[0059] A double-effect oil phase discharge collection funnel 54 is provided in the middle of the double-effect gas-liquid separator 45. The double-effect oil phase discharge collection funnel 54 is connected to the double-effect oil-water separator 57 through the double-effect oil-water discharge pipe 55.

[0060] The top of the double-effect gas-liquid separator 45 is connected to the gas phase inlet of the triple-effect evaporator heater 76 via a double-effect evaporation gas phase pipe 75. The gas flashed out of the double-effect gas-liquid separator 45 enters the shell side of the triple-effect evaporator 76 to continue heating the material. The bottom port of the double-effect gas-liquid separator 45 is connected to the inlet pipe of the double-effect evaporation circulation pump via a double-effect gas-liquid separator liquid phase circulation inclined pipe 49, and the unflashed liquid phase continues to circulate, heat, and concentrate.

[0061] The double-effect gas-liquid separator 45 is equipped with a sight glass 46, a vacuum sensor 47, and a temperature sensor 48. The outlet pipe of the double-effect evaporation circulation pump is equipped with an outlet pressure gauge 52 and a flow meter 53.

[0062] The double-effect oil-water separator 57 is equipped with a double-effect oil-water liquid seal pipe 56 and a double-effect oil-water separator heating steam distributor 63. The double-effect oil-water discharge pipe 55 is connected to the top of the double-effect oil-water liquid seal pipe 56, and the double-effect oil-water separator heating steam distributor 63 is connected to the double-effect oil-water separator heating steam main pipe 65 through the double-effect oil-water separator heating steam branch pipe 64; the side wall of the double-effect oil-water separator 57 is connected to the oil phase recovery section through the double-effect oil phase discharge pipe 60.

[0063] A heating steam control valve 62 is installed on the heating steam branch pipe 64 of the double-effect oil-water separator, and a double-effect oil phase temperature sensor 61 is installed on the double-effect oil-water separator 57. The double-effect oil phase temperature sensor 61 is connected to the heating steam control valve 62. Through the interlocking action of the double-effect oil phase temperature sensor 61 and the heating steam control valve 62, the temperature in the double-effect oil-water separator 57 can be controlled to maintain at the set value.

[0064] The bottom of the double-effect oil-water separator 57 is connected to the inlet pipe of the double-effect evaporation circulation pump 51 via the water phase recovery pipe 66, continuing to circulate, heat, and concentrate the material. The water phase recovery pipe 66 is equipped with a water phase recovery control valve 68 and a remote level controller 67.

[0065] The double-effect oil-water separator 57 is equipped with a double-effect oil-water separator vent pipe 58 and a double-effect oil-water separator sight glass 59.

[0066] The triple-effect evaporation system mainly consists of a triple-effect evaporation heater 76 and a triple-effect gas-liquid separator 86.

[0067] The top port of the triple-effect evaporator heater 76 is connected to the triple-effect gas-liquid separator 86, and the bottom port of the triple-effect evaporator heater 76 is connected to the triple-effect evaporation circulation pump 78.

[0068] The bottom port of the triple-effect gas-liquid separator 86 is connected to the triple-effect evaporation circulation pump 78 through the triple-effect evaporation circulation pipe 79, the top port of the triple-effect gas-liquid separator 86 is connected to the triple-effect evaporation condenser 89 through the triple-effect evaporation vapor phase pipe 88, and the triple-effect evaporation circulation pipe 79 is connected to the centrifuge through the triple-effect discharge pipe 81.

[0069] The triple-effect discharge pipe 81 is equipped with a triple-effect discharge flow meter 82 and a triple-effect discharge control valve 83. The discharge flow rate is controlled by the interlocking action of the triple-effect discharge flow meter 82 and the triple-effect discharge control valve 83.

[0070] The triple-effect gas-liquid separator 86 is equipped with a triple-effect evaporator temperature display 84, a triple-effect evaporator sight glass 85, and a triple-effect gas-liquid separator vacuum sensor 87. The triple-effect evaporator condenser 89 is connected to the circulating water return pipe 91 and the circulating water supply pipe 92.

[0071] The operating principle of a triple-effect evaporation system is largely the same as that of a single-effect or double-effect evaporation system. However, in a triple-effect evaporation system, salt has already precipitated out, so an oil-water separator and filter are no longer required. The concentrated evaporation liquid directly enters a centrifuge through the triple-effect discharge pipe 81 for solid-liquid separation, yielding the byproduct salt. The gas phase flashed from the triple-effect gas-liquid separator 86 directly enters the triple-effect evaporator condenser 89 to become process condensate, which is then reused in the production system or discharged in compliance with standards. The uncondensed non-condensable gas 90 from the triple-effect evaporator condenser 89 enters the vacuum system, and the condensate from the triple-effect evaporator heater 76 is directly reused in the process system or discharged in compliance with standards.

[0072] Based on the treatment system provided in the above embodiments, this embodiment provides a method for treating saline organic wastewater.

[0073] In the first-effect evaporation system, the saline organic wastewater at room temperature passes through the organic wastewater preheater 2 before entering the first-effect evaporator 6. The temperature is raised to the set value before entering the first-effect evaporator 6 from the top. Fresh heating steam is used to heat the first-effect evaporator 6. In the first-effect evaporator 6, the wastewater is forcibly circulated and heated by the first-effect evaporation circulation pump 18. The gas-water mixture enters the first-effect gas-liquid separator 12 through the first-effect gas-liquid connecting pipe for flash evaporation. The oil-water mixture is collected by the first-effect oil phase discharge collection funnel 21 and flows into the first-effect oil-water separator 24 for further sedimentation and stratification. The oil phase flows out through the first-effect oil phase discharge pipe, and the gas phase generated in the first-effect gas-liquid separator 12 enters the second-effect evaporator 43 through the first-effect evaporation gas phase pipe for further treatment.

[0074] In the double-effect evaporation system, the concentrate from the first-effect evaporator 6 enters the second-effect gas-liquid separator 45 after passing through a precision filter. When the differential pressure gauge of the precision filter reaches the set value, it needs to be switched to the standby precision filter operation. The filter bag of the filter with high differential pressure needs to be replaced. The second-effect evaporation circulation pump 51 is used for forced circulation heating. The gas-liquid mixture enters the second-effect gas-liquid separator 45 through the second-effect gas-liquid connecting pipe for flash evaporation. The oil-water mixture is collected by the second-effect oil phase discharge collection funnel 54 and flows into the second-effect oil-water separator 57 for further sedimentation and stratification. The oil phase flows out through the second-effect oil phase discharge pipe. The gas phase generated in the second-effect gas-liquid separator 45 enters the third-effect evaporation heater 76 through the second-effect evaporation gas phase pipe for further processing.

[0075] In the triple-effect evaporation system, the concentrate from the double-effect evaporator 43 enters the triple-effect gas-liquid separator 86 after passing through a precision filter. When the differential pressure gauge of the precision filter reaches the set value, it needs to be switched to the standby precision filter operation. The filter bag of the filter with high differential pressure needs to be replaced. The triple-effect evaporation circulation pump 78 is used for forced circulation heating. The gas-liquid mixture enters the triple-effect gas-liquid separator 86 for flash evaporation. The gas phase generated in the triple-effect gas-liquid separator 86 enters the triple-effect evaporation condenser 89 through the triple-effect evaporation gas phase pipe. After condensation, it is recycled as process water. The cooling medium of the triple-effect evaporation condenser 89 is circulating cooling water. The high-salinity concentrate after concentration enters the centrifuge for processing.

[0076] The scope of protection claimed by this invention is not limited to the specific embodiments described above. For those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A system for treating a salt-containing organic wastewater, characterized by comprising: The application relates to a waste water treatment device, which comprises the following parts: an organic waste water preheater for preheating normal temperature salt-containing organic waste water to a set temperature, wherein an organic waste water hot material outlet end is arranged on the organic waste water preheater; a one-effect evaporator, which has a top port and a bottom port, wherein the organic waste water hot material outlet end is connected to the top port of the one-effect evaporator, the bottom port of the one-effect evaporator is connected to a one-effect evaporation circulating pump through a one-effect evaporation circulating pump inlet pipe, and the top port of the one-effect evaporator is connected to the one-effect evaporation circulating pump through a one-effect evaporation circulating pump outlet pipe; a heating steam feeding pipe is connected to the shell side of the one-effect evaporator, fresh heating steam is input into the one-effect evaporator through the heating steam feeding pipe to heat the one-effect evaporator; a one-effect gas-liquid communication pipe is connected to a one-effect gas-liquid separation tank through the lower side wall of the one-effect evaporator; a one-effect material filtering front pipe is connected to the outlet pipe of the one-effect evaporation circulating pump, the inlet end of a one-effect precision filter is connected to the one-effect material filtering front pipe, and the outlet end of the one-effect precision filter is connected to a two-effect gas-liquid separation tank through a one-effect material filtering rear pipe; the one-effect gas-liquid separation tank, which is provided with a one-effect oil phase material collecting funnel in the middle part, and the one-effect oil phase material collecting funnel is connected to a one-effect oil-water separator through a one-effect oil-water material outlet pipe; the top of the one-effect gas-liquid separation tank is connected to the gas phase inlet end of a two-effect evaporator through a one-effect evaporation gas phase pipe; the one-effect oil-water separator, which is provided with a one-effect oil-water liquid seal pipe and a one-effect oil-water separator heating steam distributor; the top end of the one-effect oil-water material outlet pipe is connected to the one-effect oil-water liquid seal pipe, the one-effect oil-water separator heating steam distributor is connected to a one-effect oil-water separator heating steam main pipe through a one-effect oil-water separator heating steam branch pipe, and the side wall of the one-effect oil-water separator is connected to an oil phase recovery section through a one-effect oil phase material outlet pipe; a two-effect evaporator, which has a top port and a bottom port, wherein the bottom port of the two-effect evaporator is connected to a two-effect evaporation circulating pump through a two-effect evaporation circulating pump inlet pipe, and the top port of the two-effect evaporator is connected to the two-effect evaporation circulating pump through a two-effect evaporation circulating pump outlet pipe; a two-effect gas-liquid communication pipe is connected to a two-effect gas-liquid separation tank through the lower side wall of the two-effect evaporator; a two-effect material filtering front pipe is connected to the outlet pipe of the two-effect evaporation circulating pump, the inlet end of a two-effect precision filter is connected to the two-effect material filtering front pipe, and the outlet end of the two-effect precision filter is connected to a three-effect gas-liquid separation tank through a two-effect material filtering rear pipe; the two-effect gas-liquid separation tank, which is provided with a two-effect oil phase material collecting funnel in the middle part, and the two-effect oil phase material collecting funnel is connected to a two-effect oil-water separator through a two-effect oil-water material outlet pipe; the top of the two-effect gas-liquid separation tank is connected to the gas phase inlet end of a three-effect evaporation heater through a two-effect evaporation gas phase pipe; the two-effect oil-water separator, which is provided with a two-effect oil-water liquid seal pipe and a two-effect oil-water separator heating steam distributor; the top end of the two-effect oil-water material outlet pipe is connected to the two-effect oil-water liquid seal pipe, the two-effect oil-water separator heating steam distributor is connected to a two-effect oil-water separator heating steam main pipe through a two-effect oil-water separator heating steam branch pipe, and the side wall of the two-effect oil-water separator is connected to an oil phase recovery section through a two-effect oil phase material outlet pipe. --- The top port of the three-effect evaporation heater is connected to the three-effect gas-liquid separation tank, and the bottom port of the three-effect evaporation heater is connected to the three-effect evaporation circulating pump, --- The bottom port of the three-effect gas-liquid separation tank is connected to the three-effect evaporation circulating pump through a three-effect evaporation circulating pipeline, the top port of the three-effect gas-liquid separation tank is connected to the three-effect evaporation condenser through a three-effect evaporation gas phase pipeline, and the three-effect evaporation circulating pipeline is connected to the centrifuge through a three-effect discharge pipeline.

2. The system for treatment of salt-laden organic wastewater as claimed in claim 1 wherein: The bottom of the shell side of the first-effect evaporator is connected to the organic wastewater preheater through a first-effect condensate pipeline.

3. The system for treating salt-laden organic wastewater of claim 1, wherein: The bottom of the shell side of the second-effect evaporator is connected to the bottom of the shell side of the third-effect evaporator through a second-effect condensate pipeline.

4. The system for treatment of salt-laden organic wastewater as claimed in claim 1 wherein: The first-effect discharge filter front pipe is connected to the inlet end of the first-effect standby filter, and the outlet end of the first-effect standby filter is connected to the second-effect gas-liquid separation tank.

5. The system for treatment of salt-laden organic wastewater as claimed in claim 1 wherein: The second-effect discharge filter front pipe is connected to the inlet end of the second-effect standby filter, and the outlet end of the second-effect standby filter is connected to the third-effect gas-liquid separation tank.

6. The system for treatment of salt-laden organic wastewater as claimed in claim 1 wherein: The bottom port of the first-effect gas-liquid separation tank is connected to the inlet pipe of the first-effect evaporation circulating pump through a first-effect gas-liquid separation tank liquid phase circulating inclined pipe; the bottom port of the second-effect gas-liquid separation tank is connected to the inlet pipe of the second-effect evaporation circulating pump through a second-effect gas-liquid separation tank liquid phase circulating inclined pipe.

7. The system for treatment of salt-laden organic wastewater as claimed in claim 1 wherein: The bottom of the first-effect oil-water separator is connected to the inlet pipe of the first-effect evaporation circulating pump through a first-effect oil-water separator water phase recovery pipe; the bottom of the second-effect oil-water separator is connected to the inlet pipe of the second-effect evaporation circulating pump through a second-effect oil-water separator water phase recovery pipe.

8. The system for treatment of salt-laden organic wastewater as claimed in claim 1 wherein: A first-effect oil-water separator heating steam control valve is arranged on the first-effect oil-water separator heating steam branch pipe, and a first-effect oil phase temperature sensor is arranged on the first-effect oil-water separator, which is connected to the first-effect oil-water separator heating steam control valve.

9. The system for treatment of salt-laden organic wastewater as claimed in claim 1 wherein: A second-effect oil-water separator heating steam control valve is arranged on the second-effect oil-water separator heating steam branch pipe, and a second-effect oil phase temperature sensor is arranged on the second-effect oil-water separator, which is connected to the second-effect oil-water separator heating steam control valve.

10. A method for treating a salt-containing organic wastewater, characterized by: The processing system of any one of claims 1-9, Before entering the first-effect evaporator, the normal-temperature salt-containing organic wastewater is first passed through the organic wastewater preheater, the temperature is raised to a set value, and then enters the first-effect evaporator from the top; fresh heating steam is used to heat the first-effect evaporator; in the first-effect evaporator, a first-effect evaporation circulating pump is used to forcibly circulate and heat the wastewater, the gas-water mixture enters the first-effect gas-liquid separation tank through a first-effect gas-liquid communication pipe for flashing, the oil-water mixed phase is collected by a first-effect oil phase discharge collection funnel, flows into a first-effect oil-water separator for further settlement and stratification, the oil phase flows out through a first-effect oil phase discharge pipe, and the gas phase generated in the first-effect gas-liquid separation tank enters the second-effect evaporator through a first-effect evaporation gas phase pipe for further treatment; In the two-effect evaporation system, the concentrated liquid from the one-effect evaporator enters the two-effect gas-liquid separation tank after passing through the precision filter, and is heated by forced circulation using the two-effect evaporation circulating pump. The gas-water mixture enters the two-effect gas-liquid separation tank through the two-effect gas-liquid communication pipe for flash evaporation. The oil-water mixture is collected by the two-effect oil phase outlet collection funnel, flows into the two-effect oil-water separator for further settlement and stratification, and the oil phase flows out through the two-effect oil phase outlet pipe. The gas phase generated in the two-effect gas-liquid separation tank enters the three-effect evaporator through the two-effect evaporation gas phase pipe for further treatment. In the three-effect evaporation system, the concentrated liquid from the two-effect evaporator enters the three-effect gas-liquid separation tank after passing through the precision filter, and is heated by forced circulation using the three-effect evaporation circulating pump. The gas-water mixture enters the three-effect gas-liquid separation tank for flash evaporation. The gas phase generated in the three-effect gas-liquid separation tank enters the three-effect evaporation condenser through the three-effect evaporation gas phase pipe. The cooling medium of the three-effect evaporation condenser is circulating cooling water. The high-salinity concentrated liquid after concentration enters the centrifuge for treatment.

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