CN109111002B

CN109111002B - Shale gas effluent treatment plant based on MVR technique

Info

Publication number: CN109111002B
Application number: CN201810935673.4A
Authority: CN
Inventors: 汪锐; 潘志成; 陈婷婷; 彭玉梅; 陈科西; 邱恋; 徐国建
Original assignee: Chengdu Keda Environmental Protection Industry Technology Research Institute Co ltd
Current assignee: Chengdu Keda Environmental Protection Industry Technology Research Institute Co ltd
Priority date: 2018-08-16
Filing date: 2018-08-16
Publication date: 2021-03-12
Anticipated expiration: 2038-08-16
Also published as: CN109111002A

Abstract

The invention discloses a shale gas wastewater treatment device based on an MVR (mechanical vapor recompression) technology, which belongs to the technical field of shale gas wastewater treatment and comprises a wastewater collection tank, an oil separation tank, a coagulating oxidation sedimentation tank, an artificial infiltration tank, a clear water temporary storage tank, a filtering device and an MVR distillation treatment device which are sequentially communicated according to a wastewater treatment sequence; the oil separation tank comprises a tank body, lifting devices symmetrically arranged on two sides of the inner wall of the tank body and an oil liquid collecting device arranged between the lifting devices; the oil liquid collecting device comprises a shell, an adsorption bucket, an air suction pump, an oil suction pump, a conveying device, a floating trigger device, a microprocessor and a driving motor; the floating trigger device comprises a device body, a sliding cavity, a floating block, a top block and a pressure-sensitive sensor. The MVR technology is introduced to treat the shale gas wastewater, the treatment effect is good, oil can be synchronously removed along with the rise of the sewage water surface, and impurities in the shale gas wastewater can be effectively filtered.

Description

Shale gas effluent treatment plant based on MVR technique

Technical Field

The invention relates to the technical field of shale gas wastewater treatment, in particular to a shale gas wastewater treatment device based on an MVR (mechanical vapor recompression) technology.

Background

Shale gas is natural gas extracted from shale layers, the main body of the shale gas is located in dark shale or high-carbon shale, the shale gas is natural gas which exists in shale, high-carbon shale, shale and silty rock interlayer in a free state or a free state on the main body of the natural gas in cracks, pores and other reservoir spaces in a free phase state (about 50%) at various stages of organic origin, the shale gas exists on the surfaces of kerogen, clay particles and pores in an adsorption state (about 50%), and the shale gas is stored in kerogen, asphaltene and petroleum in a dissolving state in a very small amount. The shale gas exploitation technology mainly comprises a horizontal well technology, a multi-layer fracturing technology, a clean water fracturing technology and a repeated fracturing technology. In the treatment of the shale gas wastewater, the MVR technology is less applied, the MVR is a short name of a mechanical vapor recompression (mechanical vapor recompression) technology, secondary vapor generated by an evaporation system and energy thereof are utilized, work is performed by compressing the secondary vapor through a vapor compressor, the enthalpy of the secondary vapor is improved, the secondary vapor is guided into a cooling tower, and cooling water of the cooling tower is circulated to preheat materials. The circulation provides heat energy for the evaporation system, thereby reducing the requirement on external energy.

The main pollutants of the wastewater generated in the shale gas exploitation process are oil components, but when polymer is adopted for oil displacement or fracturing, the produced water or fracturing flowback fluid contains a large amount of polymers, so that the viscosity of the wastewater is greatly improved, and a large amount of flocculation solid matters are formed because fine oil drops are wrapped by a large amount of high-molecular polymer inclusion capsules, so that the large amount of quick elimination and cleaning are difficult to realize and the emission or reuse standard is reached; impurities and the like are inevitably present in the generated wastewater, and if the impurities are not treated, the treatment effect and efficiency of the wastewater are influenced; the treatment effect of the existing oil separation tank on the surface of the wastewater cannot be better collected.

The prior art is as follows: in a patent document with a patent number of CN201710033367.7 in the Chinese invention patent, a shale gas wastewater treatment method is disclosed, which comprises the following steps: step 1, separating oil from water in the shale gas wastewater; step 2, performing Fenton reaction on the sewage after the waste oil is separated, adding a coagulant for precipitation, filtering and drying precipitated solid floc, and allowing filtered supernatant to enter the next step; and 3, after the liquid in the step 2 is subjected to artificial percolation, sequentially filtering the liquid by a walnut shell filter and a modified fiber ball filter, wherein the artificial percolation is that the liquid sequentially passes through filter layers with different particle sizes. The shale gas wastewater treatment system comprises a wastewater collection tank, an oil separation tank, a coagulating, oxidizing and precipitating tank, an artificial infiltration tank, a clear water temporary storage tank, a walnut shell filter and a modified fiber ball filter which are sequentially connected. The invention effectively reduces the concentration of flocculate in the sewage, the treated wastewater meets the national relevant environmental protection requirements, can be directly discharged outwards or recycled for shale gas mining water, and has obvious environmental protection effect and economic benefit. However, the water body treated by the method has poor water quality, and can only be used for secondary water developed by shale gas or water with the same water quality requirement, so that the treated water has less use.

Disclosure of Invention

The invention aims to provide a shale gas wastewater treatment device based on MVR technology, which realizes the functions of collecting impurities and automatically cleaning oil, and has the effects of automatically rising along with the rise of the water surface of sewage and effectively treating and utilizing the sewage.

The invention is realized by the following technical scheme:

a shale gas wastewater treatment device based on MVR technology comprises a wastewater collection tank, an oil separation tank, a coagulating, oxidizing and precipitating tank, an artificial infiltration tank, a clear water temporary storage tank, a filtering device and an MVR distillation treatment device which are sequentially communicated according to a wastewater treatment sequence; the oil separation tank comprises a tank body, lifting devices symmetrically arranged on two sides of the inner wall of the tank body and an oil liquid collecting device arranged between the lifting devices, and the lifting devices drive the oil liquid collecting device to move up and down; the oil liquid collecting device comprises a shell, an adsorption bucket, an air suction pump, an oil suction pump, a conveying device, a floating triggering device, a microprocessor and a driving motor, wherein fixed supports are symmetrically arranged at two ends of the bottom of the shell, the conveying device is arranged on the fixed supports, a plurality of oil scraping plates are arranged on a conveying belt of the conveying device, and the driving motor for driving the conveying device to rotate is arranged in the shell; an adsorption hopper with a downward hopper opening is arranged between the fixed supports, the top end of the adsorption hopper is communicated with an oil suction cavity arranged in the shell through a suction pipe, an air suction pump communicated with the oil suction cavity through an air inlet is arranged in the shell on one side of the oil suction cavity, and a filter cover is arranged on the air inlet of the air suction pump; an oil suction pump is arranged on the shell, an oil suction port of the oil suction pump is communicated with the oil suction cavity through an oil suction pipe, and an oil outlet of the oil suction pump is connected with an oil outlet pipe extending out of the oil separating tank; the floating trigger device comprises a device body which is vertically arranged at the bottom of the shell and is hollow inside, a sliding cavity arranged inside the lower end of the device body, a floating block which is arranged in the sliding cavity in a sliding mode and a pressure-sensitive sensor embedded in the top end of the device body, wherein an opening communicated with the sliding cavity is formed in the bottom of the device body, and a top block which is matched with the detection end of the pressure-sensitive sensor is vertically arranged at the top of the floating block; the microprocessor is arranged in the shell and is respectively connected with the pressure-sensitive sensor, the driving motor, the lifting device, the oil suction pump and the air suction pump.

In order to better realize the invention, an impurity collecting device is arranged in the wastewater collecting tank, the impurity collecting device comprises a bucket-shaped filtering grid, a collecting frame, an electric push rod, a water pump and an opening and closing cover, the filtering grid is arranged on the inner wall of the wastewater collecting tank, the bottom of the filtering grid is communicated with the collecting frame arranged at the bottom of the wastewater collecting tank, one side of the top of the collecting frame is hinged with one end of the opening and closing cover, and the other end of the opening and closing cover is hinged with the electric push rod arranged on the inner wall of the collecting frame; one side of the bottom of the collecting frame is provided with a water outlet, the water outlet is communicated with the upper end of the waste water collecting tank through a water pump, and a filter screen is arranged at the water outlet.

In order to better realize the invention, the MVR distillation treatment device comprises a condensation preheater, a pressure pump, an evaporation chamber, a return pipe, a vapor compressor, a T-shaped pipe, a screw pump and a condensation water pump, wherein the filtering device is connected with the condensation preheater through the pressure pump, the left end of the condensation preheater is connected with the evaporation chamber through a pipeline, the top of the evaporation chamber is provided with the return pipe, the other end of the return pipe, which is far away from the evaporation chamber, is connected with the vapor compressor, the left end of the vapor compressor is provided with the T-shaped pipe, and the left end of the T-shaped pipe is connected to the right side wall of the evaporation chamber; the bottom of evaporation chamber has the screw pump through the pipe connection, the output of screw pump has crystal thick liquid recovery tank through the pipe connection, the top at the condensation preheater is connected to the bottom of T type pipe, condensation preheater's bottom has the collection box through the pipe connection, the right-hand member of collection box is provided with the vacuum pump, there is the water storage tank bottom of collection box through the pipe connection.

In order to better implement the invention, further, the lifting device is a lifting conveyor belt or a lifting rope.

In order to better realize the invention, the system further comprises a master controller, wherein the master controller is respectively connected with the microprocessor, the electric push rod, the water pump, the condensation preheater, the booster pump, the evaporation chamber, the steam compressor and the screw pump.

In order to better realize the invention, a slag discharge port communicated with the collecting frame is further arranged at the bottom of the wastewater collecting tank, and an opening and closing valve is arranged on the slag discharge port.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) according to the invention, the shale gas wastewater can be effectively treated through the wastewater collection tank, the oil separation tank, the coagulating oxidation sedimentation tank, the artificial infiltration tank, the filtering device and the MVR distillation treatment device which are sequentially communicated according to the wastewater treatment sequence, and the shale gas wastewater can be used in various aspects, such as domestic water, irrigation water, cleaning water and the like, when a water body with better water quality can be obtained through the MVR distillation treatment device.

(2) According to the invention, the oil collecting device and the lifting device are arranged in the oil separating tank, the oil collecting device can detect whether the water surface rises through the floating triggering device, and can rise along with the rising of the water surface under the driving of the lifting device; meanwhile, the oil on the surface of the sewage is effectively collected and discharged through the conveying device, the oil scraping plate, the adsorption bucket, the oil suction cavity, the air suction pump and the oil suction pump, and the device is efficient and practical.

(3) According to the invention, by arranging the impurity collecting device, not only can the shale gas wastewater be filtered, but also the filtered impurities can be automatically collected, the sewage in the collecting frame can be prevented from being discharged along with the impurities, a circulation is formed, the collecting effect is good, and the structure is simple and practical.

Drawings

FIG. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic structural view of an oil collecting device of the oil-separating tank of the present invention;

fig. 3 is a schematic structural diagram of the floating trigger device of the present invention.

Wherein: 1-a wastewater collection tank; 11-a filter grid; 12-opening and closing the cover; 13-a collection frame; 14-an electric push rod; 15-a slag discharge port; 16-a filter screen; 2-oil separation tank; 21-a lifting device; 211-a lifting mechanism; 212-a drive mechanism; 22-oil collection means; 221-a housing; 222-a microprocessor; 223-driving the motor; 224-an oil suction pump; 225-oil suction chamber; 226-a filter cage; 227-air pump; 228-floating trigger device; 2281 — a pressure sensitive sensor; 2282 — a device body; 2283-top piece; 2284-floating block; 229-a transfer device; 2210-oil scraper; 2211-oil outlet pipe; 3-a coagulating, oxidizing and precipitating tank; 4-artificial infiltration pond; 5-temporary storage pool of clear water; 6-a filtration device; 7-MVR distillation treatment device; 71-an evaporation chamber; 72-screw pump; 73-a return pipe; a 74-T shaped tube; 75-a vapor compressor; 76-a condensation preheater; 77-a recovery box; 78-vacuum pump; 79-pressure pump; 8-water storage tank; 9-crystal mush recovery tank.

Detailed Description

With reference to the attached drawings 1-3, a shale gas wastewater treatment device based on MVR technology comprises a wastewater collection tank 1, an oil separation tank 2, a coagulation oxidation sedimentation tank 3, an artificial infiltration tank 4, a clear water temporary storage tank 5, a filtering device 6 and an MVR distillation treatment device 7 which are sequentially communicated according to a wastewater treatment sequence; the oil separation tank 2 comprises a tank body, lifting devices 21 symmetrically arranged on two sides of the inner wall of the tank body and an oil liquid collecting device 22 arranged between the lifting devices 21, wherein the lifting devices 21 drive the oil liquid collecting device 22 to move up and down; the oil liquid collecting device 22 comprises a shell 221, an adsorption bucket, an air suction pump 227, an oil suction pump 224, a conveying device 229, a floating triggering device 228, a microprocessor 222 and a driving motor 223, wherein fixed supports are symmetrically arranged at two ends of the bottom of the shell 221, the conveying device 229 is arranged on the fixed supports, a plurality of oil scraping plates 2210 are arranged on a conveying belt of the conveying device 229, and the driving motor 223 for driving the conveying device 229 to rotate is arranged in the shell 221; an adsorption bucket with a downward bucket opening is arranged between the fixed brackets, the top end of the adsorption bucket is communicated with an oil suction cavity 225 arranged in the shell 221 through a suction pipe, an air suction pump 227 communicated with the oil suction cavity 225 through an air inlet is arranged in the shell 221 on one side of the oil suction cavity 225, and a filter cover 226 is arranged on the air inlet of the air suction pump 227; an oil suction pump 224 is arranged on the shell 221, an oil suction port of the oil suction pump 224 is communicated with the oil suction cavity 225 through an oil suction pipe, and an oil outlet of the oil suction pump 224 is connected with an oil outlet pipe 2211 extending out of the oil separation tank 2; the floating trigger device 228 comprises a device body 2282 which is vertically arranged at the bottom of the shell 221 and is hollow inside, a sliding cavity arranged inside the lower end of the device body 2282, a floating block 2284 which is slidably arranged in the sliding cavity, and a pressure-sensitive sensor 2281 which is embedded in the top end of the device body 2282, wherein an opening communicated with the sliding cavity is arranged at the bottom of the device body 2282, and a top block 2283 which is matched with the detection end of the pressure-sensitive sensor 2281 is vertically arranged at the top of the floating block 2284; the microprocessor 222 is disposed in the housing 221 and is connected to the pressure sensor 2281, the driving motor 223, the lifting device 21, the oil suction pump 224, and the air suction pump 227.

Because a large amount of oil substances exist in the shale gas wastewater discharged by mining, and the flocculate and the oil substances float on the surface of the sewage, the oil substances on the surface of the sewage are removed through the oil separation tank 2; when the sewage continuously enters the oil-separating tank 2, the depth of the sewage is continuously increased, when the surface of the sewage contacts the floating block 2284 of the floating trigger device 228, the floating block 2284 moves upwards in the sliding cavity at the lower end of the device body 2282 along with the rise of the water surface, the top block 2283 on the floating block 2284 contacts the pressure-sensitive sensor 2281, the pressure-sensitive sensor 2281 transmits the detected information to the microprocessor 222, the microprocessor 222 sends a rise starting signal to the lifting device 21, the lifting devices 21 on the two sides rise synchronously, the oil collecting device 22 between the two sides is driven to rise by a certain height and collect the oil, when the height of the sewage rises again and the rising information is detected by the floating block 2284 and the pressure-sensitive sensor 2281, the oil collecting device 22 is lifted by a certain distance through the lifting device 21 again, and the certain distance is the distance between the upper oil scraping plate and the lower oil scraping plate on the transmission device, therefore, the oil liquid collection and the collection of a small amount of flocculate can be carried out while the height of the sewage water surface is continuously raised; the driving motor 223 in the housing 221 drives the conveyer 229 to rotate, the conveyer 229 is preferably a conveyer belt type conveyer, which makes the oil scraping plates 2210 on the conveyer 229 rotate and scrape oil, the rotating directions of the conveyer 229 at both ends are opposite, so that the oil and flocculate at both sides can be scraped to the middle by the oil scraping plates 2210 at both ends and sucked into the oil suction cavity 225 through the adsorption buckets communicated with the oil suction cavity 225, the oil suction cavity 225 generates adsorption force in the oil suction cavity 225 through the suction pump 227, the oil and flocculate in the oil suction cavity 225 are sucked out through the oil suction pipe of the oil suction pump 224 and discharged through the oil outlet 2211, thereby realizing the collection and treatment of the oil and little flocculate on the surface of the sewage; simple structure, it is practical convenient, along with the rising of sewage surface of water and automatic collection fluid, flocculation thing that can be automatic.

Further, as a preference of different embodiments, an impurity collecting device is arranged in the wastewater collecting tank 1, the impurity collecting device includes a bucket-shaped filtering grille 11, a collecting frame 13, an electric push rod 14, a water pump and an opening and closing cover 12, the filtering grille 11 is arranged on the inner wall of the wastewater collecting tank 1, the bottom of the filtering grille 11 is communicated with the collecting frame 13 arranged at the bottom of the wastewater collecting tank 1, one side of the top of the collecting frame 13 is hinged with one end of the opening and closing cover 12, and the other end of the opening and closing cover 12 is hinged with the electric push rod 14 arranged on the inner wall of the collecting frame 13; a water outlet is formed in one side of the bottom of the collecting frame 13 and communicated with the upper end of the waste water collecting tank 1 through a water pump, and a filter screen 16 is arranged at the water outlet.

The sewage discharged during exploitation when the shale gas is used as the wastewater, wherein impurities are inevitably present; when sewage enters the wastewater collection tank 1, the wastewater is filtered through the filtering grids 11, the filtering grids 11 can filter impurities, and the impurities generated by filtering can be gathered at the bottom of the filtering grids 11 through the bucket-shaped filtering grids 11; when impurities are gathered to a certain amount, the electric push rod 14 drives the opening and closing cover 12 to be opened, so that the impurities on the cover body fall down into the collecting frame 13 to be collected, and then the electric push rod 14 drives the hinged opening and closing cover 12 to close the opening and closing cover 12; the wastewater in the collecting frame 13 is pumped into the wastewater collecting tank 1 again through a water pump for filtering; the opening interval of the cover closing cover can be detected through the weight of accumulated impurities through a pressure sensor, and when the detected pressure reaches the preset upper pressure limit, the electric push rod 14 is started to open and close the opening and closing cover 12; meanwhile, the opening and closing of the opening and closing cover 12 can be timed through a timer, and the opening and closing actions are carried out at intervals, so that the impurities gathered at the bottom of the filter grille 11 are collected; simple structure, can be automatic collect filterable impurity, it is practical convenient.

Further, as a preference of different embodiments, the MVR distillation processing device 7 includes a condensation preheater 76, a pressure pump 79, an evaporation chamber 71, a return pipe 73, a vapor compressor 75, a T-shaped pipe 74, a screw pump 72 and a condensate pump, the filtering device 6 is connected with the condensation preheater 76 through the pressure pump 79, the left end of the condensation preheater 76 is connected with the evaporation chamber 71 through a pipeline, the top of the evaporation chamber 71 is provided with the return pipe 73, the other end of the return pipe 73 away from the evaporation chamber 71 is connected with the vapor compressor 75, the left end of the vapor compressor 75 is provided with the T-shaped pipe 74, and the left end of the T-shaped pipe 74 is connected to the right side wall of the evaporation chamber 71; the bottom of evaporation chamber 71 has screw pump 72 through the pipe connection, the output of screw pump 72 has magma recovery tank 9 through the pipe connection, the bottom of T type pipe 74 is connected at the top of condensation pre-heater 76, the bottom of condensation pre-heater 76 has collection box 77 through the pipe connection, the right-hand member of collection box 77 is provided with vacuum pump 78, the bottom of collection box 77 has water storage tank 8 through the pipe connection.

The sewage filtered by the filtering device 6 is pressurized by a pressurizing pump 79, so that the sewage has enough kinetic energy to enter a condensing preheater 76, the condensing preheater 76 preheats the entered sewage, the heated sewage enters an evaporation chamber 71 to be evaporated and crystallized, crystal slurry in the evaporation chamber 71 enters a screw pump 72 through a pipeline, the crystal slurry in the evaporation chamber 71 enters a crystal slurry recovery tank 9 to be uniformly collected, water vapor in the evaporation chamber 71 enters a vapor compressor 75 through a return pipe 73, the vapor can be condensed to enter a T-shaped pipe 74, distilled water in the compressed vapor enters the condensing preheater 76 through the T-shaped pipe 74, other gases in the compressed vapor enter the evaporation chamber 71 through the T-shaped pipe 74, the distilled water entering the condensing preheater 76 enters a recovery tank 77 through a pipeline, the recovery tank 77 is in a negative pressure state through a vacuum pump 78, the distilled water can enter the recovery tank 77, the water in the recovery tank 77 flows into the water storage tank 8 for storage, and the water in the water outlet tank has higher purity and can be used as a multi-aspect water source.

Further, as a preference of different embodiments, the lifting device 21 is a lifting conveyor belt or a lifting rope.

The lifting device 21 can adopt different lifting mechanisms 211, so that the oil collecting device 22 can be lifted up and down, and the driving mechanism 212 of the lifting device 21 is arranged at the top of the oil separating tank 2.

Further, as a preference of different embodiments, the system further comprises a general controller, and the general controller is respectively connected with the microprocessor 222, the electric push rod 14, the water pump, the condensation preheater 76, the booster pump 79, the evaporation chamber 71, the vapor compressor 75 and the screw pump 72.

The main controller respectively controls the microprocessor 222, the electric push rod 14, the water pump, the condensation preheater 76, the booster pump 79, the evaporation chamber 71, the vapor compressor 75 and the screw pump 72; the master controller adopts a PLC controller.

Further, as the optimization of different embodiments, the bottom of the wastewater collection tank 1 is provided with a slag discharge port 15 communicated with the collection frame 13, and the slag discharge port 15 is provided with an opening and closing valve.

The working process of the invention is as follows:

shale gas waste water is collected in getting into the waste water collecting pit through the inlet tube, control impurity collection device through total controller, and filter the collection with impurity through impurity collection device to the waste water that gets into, handle, waste water after filtering then flows into in the oil separating jar 2 in the waste water collecting tank 1, through elevating gear 21 in the oil separating jar 2, fluid collection device 22 is to the fluid on waste water surface, the flocculation thing is collected, waste oil through such oil-water separation mode separation can be retrieved and is sent to the oil refinery as the raw materials, waste water after oil-water separation then gets into in the coagulating oxidation sedimentation tank 3, mainly handle the flocculation thing, utilize the fenton reaction to go on. The Fenton reaction is to add ferrous sulfate (FeSO 4) and hydrogen peroxide (H2O 2) into the wastewater, and to utilize the principle that the ferrous sulfate and the hydrogen peroxide have strong oxidizability after being mixed, a great amount of organic compounds such as carboxylic acid, alcohol, ester and the like in the shale gas wastewater are oxidized and degraded into inorganic substances. After the Fenton reaction is finished, the flocculate is settled and dried, the dried solid can be buried or treated by other treatments, a drying tank can be arranged for storing the flocculate, and penetrating fluid of the drying tank can be recycled to the waste water collecting tank. After the Fenton reaction, the artificial infiltration pond 4 is used for filtering flocculates, and because the quantity of polymers used in the exploitation process of the shale gas is large, in the Fenton reaction, ferric iron salt obtained after ferrous sulfate is oxidized also exists in a flocculate state, so that the density of the flocculates is further increased, and although partial flocculates are precipitated after the Fenton reaction is finished, a large number of non-adhesive small-particle suspended flocculates still exist in sewage in the actual operation process; the artificial infiltration tank 4 is used for filtering flocculate, the infiltration process is a process for separating out solid in a solid-liquid mixture, and most of the flocculate is collected; after the artificial infiltration is finished, the sewage enters a clear water temporary storage pool 5 for convenient temporary storage; the water body in the clear water temporary storage pool 5 enters a filtering device 6 through a pipeline for filtering, a quartz sand filtering layer and an active carbon filtering layer are arranged in the filtering device 6, and the water body is filtered through the two filtering layers; the water body filtered by the filtering device 6 enters the MVR distillation treatment device 7 to be treated, so that the water body with higher purity is obtained, the shale gas wastewater is effectively treated, and the shale gas wastewater can be used for various aspects such as domestic water, flushing water and the like.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.

Claims

1. The utility model provides a shale gas effluent treatment plant based on MVR technique which characterized in that: comprises a wastewater collecting tank (1), an oil separating tank (2), a coagulating oxidation sedimentation tank (3), an artificial infiltration tank (4), a clear water temporary storage tank (5), a filtering device (6) and an MVR distillation treatment device (7) which are sequentially communicated according to a wastewater treatment sequence; the oil separation tank (2) comprises a tank body, lifting devices (21) symmetrically arranged on two sides of the inner wall of the tank body and oil liquid collecting devices (22) arranged between the lifting devices (21), wherein the lifting devices (21) drive the oil liquid collecting devices (22) to move up and down; the oil liquid collecting device (22) comprises a shell (221), an adsorption bucket, an air suction pump (227), an oil suction pump (224), a conveying device (229), a floating triggering device (228), a microprocessor (222) and a driving motor (223), wherein two ends of the bottom of the shell (221) are symmetrically provided with fixing supports, the fixing supports are provided with the conveying device (229), a conveying belt of the conveying device (229) is provided with a plurality of oil scraping plates (2210), and the shell (221) is internally provided with the driving motor (223) for driving the conveying device (229) to rotate; an adsorption bucket with a downward bucket opening is arranged between the fixed supports, the top end of the adsorption bucket is communicated with an oil suction cavity (225) arranged in the shell (221) through a suction pipe, an air suction pump (227) communicated with the oil suction cavity (225) through an air inlet is arranged in the shell (221) on one side of the oil suction cavity (225), and a filter cover (226) is arranged on the air inlet of the air suction pump (227); an oil suction pump (224) is arranged on the shell (221), an oil suction port of the oil suction pump (224) is communicated with the oil suction cavity (225) through an oil suction pipe, and an oil outlet of the oil suction pump (224) is connected with an oil outlet pipe (2211) extending out of the oil separation tank (2); the floating trigger device (228) comprises a device body (2282) which is vertically arranged at the bottom of the shell (221) and is hollow inside, a sliding cavity arranged inside the lower end of the device body (2282), a floating block (2284) which is arranged in the sliding cavity in a sliding mode, and a pressure-sensitive sensor (2281) which is embedded in the top end of the device body (2282), wherein an opening communicated with the sliding cavity is formed in the bottom of the device body (2282), and a top block (2283) which is matched with the detection end of the pressure-sensitive sensor (2281) is vertically arranged at the top of the floating block (2284); the microprocessor (222) is arranged in the shell (221) and is respectively connected with the pressure-sensitive sensor (2281), the driving motor (223), the lifting device (21), the oil suction pump (224) and the air suction pump (227).

2. The shale gas wastewater treatment device based on MVR technology of claim 1, characterized in that: the waste water collecting tank (1) is internally provided with an impurity collecting device, the impurity collecting device comprises a bucket-shaped filtering grid (11), a collecting frame (13), an electric push rod (14), a water pump and an opening and closing cover (12), the filtering grid (11) is arranged on the inner wall of the waste water collecting tank (1), the bottom of the filtering grid (11) is communicated with the collecting frame (13) arranged at the bottom of the waste water collecting tank (1), one side of the top of the collecting frame (13) is hinged with one end of the opening and closing cover (12), and the other end of the opening and closing cover (12) is hinged with the electric push rod (14) arranged on the inner wall of the collecting frame (13); one side of the bottom of the collecting frame (13) is provided with a water outlet, the water outlet is communicated with the upper end of the waste water collecting tank (1) through a water pump, and a filter screen (16) is arranged at the position of the water outlet.

3. The shale gas wastewater treatment device based on MVR technology of claim 2, characterized in that: the MVR distillation treatment device (7) comprises a condensation preheater (76), a pressure pump (79), an evaporation chamber (71), a return pipe (73), a vapor compressor (75), a T-shaped pipe (74), a screw pump (72) and a condensate pump, wherein the filtering device (6) is connected with the condensation preheater (76) through the pressure pump (79), the left end of the condensation preheater (76) is connected with the evaporation chamber (71) through a pipeline, the return pipe (73) is arranged at the top of the evaporation chamber (71), the other end, far away from the evaporation chamber (71), of the return pipe (73) is connected with the vapor compressor (75), the T-shaped pipe (74) is arranged at the left end of the vapor compressor (75), and the left end of the T-shaped pipe (74) is connected to the right side wall of the evaporation chamber (71); the bottom of evaporation chamber (71) has screw pump (72) through the pipe connection, the output of screw pump (72) has magma recovery tank (9) through the pipe connection, the top at condensation preheater (76) is connected to the bottom of T type pipe (74), there is collection box (77) bottom through the pipe connection of condensation preheater (76), the right-hand member of collection box (77) is provided with vacuum pump (78), there is water storage tank (8) bottom through the pipe connection of collection box (77).

4. The shale gas wastewater treatment device based on MVR technology of claim 3, characterized in that: the system also comprises a master controller, wherein the master controller is respectively connected with the microprocessor (222), the electric push rod (14), the water pump, the condensation preheater (76), the booster pump (79), the evaporation chamber (71), the vapor compressor (75) and the screw pump (72).

5. The shale gas wastewater treatment device based on MVR technology of claim 1, characterized in that: the lifting device (21) is a lifting transmission belt or a lifting rope.

6. The shale gas wastewater treatment device based on MVR technology of claim 2, characterized in that: waste water collection tank (1) bottom is equipped with row's cinder notch (15) with collection frame (13) intercommunication, be equipped with the open and close valve on row cinder notch (15).