Oil refining sewage treatment system and method

Abstract

The invention provides an oil refining sewage treatment system and method, and belongs to the field of sewage treatment. The system comprises an oil removal pretreatment unit, a biochemical treatment unit and a deep treatment unit which are sequentially connected according to the water flow running direction, the oil removal pretreatment unit comprises an adjusting buffer tank, a cyclone flotation separation tank and an MPE separator which are connected in sequence; the biochemical treatment unit comprises an anoxic fluidized bed reactor, an aerobic fluidized bed reactor and a settling tank which are connected in sequence; the advanced treatment unit comprises a high-position coagulation reaction tank, a high-efficiency quicksand filter and a catalytic ozonation reactor which are connected in sequence. According to the invention, the oil refining sewage is treated in a device and closed manner, the occupied area is saved, and the on-site peculiar smell is reduced; the short-process and low-cost treatment of the oil refining sewage is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a refinery sewage treatment system and method. Background Art

[0002] At present, the main treatment method for refinery wastewater is centralized mixing, that is, the oily wastewater, sulfur-containing wastewater, purified water after stripping pretreatment, production wastewater and domestic wastewater discharged from various production units are mixed and discharged after being treated to meet the standards through a combined oil separation-flotation-biochemical process. However, with the increasingly deteriorating properties of crude oil processed by refining and chemical companies and the increasingly stringent requirements for wastewater reuse due to water shortages, this centralized sewage mixing treatment method and treatment process have exposed more and more problems.

[0003] First, the proportion of high-sulfur and high-acid crude oil mining and processing is increasing year by year, which has led to an increase in the concentration of emulsified oil, difficult-to-degrade organic pollutants, sulfides, ammonia nitrogen and inorganic salts in the wastewater generated during the oil processing process, especially the electro-desalting wastewater with obvious emulsification and high salt content, oil products containing alkali, sulfur and phenol, liquefied petroleum gas, dry gas or dry gas refined alkali washing waste alkali liquid, and oil tank area cut water with high content of petroleum and organic pollutants. Although the total amount of these three types of wastewater is not large and accounts for a small proportion of the total wastewater discharge of the enterprise, the total amount of pollutants accounts for a large proportion of the total amount of pollutants in the enterprise due to the high concentration of pollutants. In addition, the wastewater has a high degree of emulsification and poor biodegradability, which frequently impacts the oil removal effect of the oil separator of the sewage treatment plant, the first-level flotation oil removal unit and the stability of the biochemical treatment unit, which has seriously threatened the stable compliance treatment and comprehensive qualification rate of the wastewater of the oil refinery.

[0004] Secondly, with the increasing shortage of water resources, it is necessary to deeply treat refinery wastewater and reuse it as circulating water, industrial water or boiler feed water. However, the inorganic salt and biodegradable COD content in the wastewater is difficult to meet the index requirements for water reuse. Reverse osmosis, electrodialysis and other methods are further used to remove inorganic salts and reduce conductivity. However, this process is difficult to apply on a large scale due to the high investment and operating costs, which has caused a great bottleneck for the green and sustainable development of the refinery industry. Therefore, the development of efficient, energy-saving, device-based and automated treatment processes and equipment has become the main trend in the development of refinery wastewater treatment. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and provide a refinery wastewater treatment system and method, so as to realize the equipment-based and closed treatment of refinery wastewater, save floor space, reduce on-site odor, and achieve the effluent water quality reaching the advanced level in the industry.

[0006] The present invention is achieved through the following technical solutions:

[0007] In a first aspect of the present invention, there is provided a refinery wastewater treatment system, which comprises an oil removal pretreatment unit, a biochemical treatment unit and a deep treatment unit connected in sequence according to the direction of water flow;

[0008] The oil removal pretreatment unit includes a regulating buffer tank, a cyclone flotation separation tank and an MPE separator connected in sequence;

[0009] The biochemical treatment unit includes an anoxic fluidized bed reactor, an aerobic fluidized bed reactor and a settling tank connected in sequence;

[0010] The deep treatment unit includes a high-level coagulation reaction tank, a high-efficiency quicksand filter and an ozone catalytic oxidation reactor which are connected in sequence.

[0011] A further improvement of the present invention is:

[0012] A micro-bubble generator is also connected between the regulating buffer tank and the cyclone flotation separation tank, and a water inlet pump is provided on the pipeline connecting the water outlet of the regulating buffer tank and the water inlet of the micro-bubble generator.

[0013] A further improvement of the present invention is:

[0014] The anoxic fluidized bed reactor comprises an anoxic reactor body, an anoxic water inlet, a nitrate liquid return port and a sludge return port are arranged at the lower part of the side wall of the anoxic reactor body, and a liquid outlet is arranged at the upper part of the side wall; and / or,

[0015] A guide tube is arranged in the anoxic reactor body, and a submersible flow propeller is installed in the guide tube to fully mix the sewage, the return sludge and the return nitrate liquid.

[0016] A further improvement of the present invention is:

[0017] The aerobic fluidized bed reactor comprises an aerobic reactor body, wherein the lower part of the side wall of the aerobic reactor body is provided with an aerobic water inlet, and the upper part is provided with a water outlet overflow port; and / or,

[0018] A plurality of aerobic inner cylinders are arranged in the aerobic reactor body, and fillers are arranged in the aerobic inner cylinders. A plurality of microporous aerators are arranged under each aerobic inner cylinder, and the microporous aerators are connected to an aeration fan located outside the aerobic reactor body through a pipeline.

[0019] A further improvement of the present invention is:

[0020] A spray water annular pipe is arranged at the upper part of the aerobic reactor body, and a plurality of small holes are evenly arranged at the bottom of the spray water annular pipe;

[0021] A plurality of spray water pipes are arranged on the top of the aerobic reactor body, and the spray water annular pipe and the spray water pipes are both connected to an external water pipe for defoaming the liquid surface.

[0022] A further improvement of the present invention is:

[0023] A degassing tank is further connected between the aerobic fluidized bed reactor and the settling tank; and / or,

[0024] The degassing tank comprises a degassing tank body, a water inlet is arranged at the upper part of the side wall of the degassing tank body, an overflow outlet is arranged at the side opposite to the water inlet, and the position of the overflow outlet is lower than the position of the water inlet; and / or,

[0025] A nitrate liquid outlet is arranged at the bottom of the degassing tank body, and the nitrate liquid outlet is communicated with the nitrate liquid outlet on the anoxic reactor body through a pipeline, and a nitrate liquid reflux pump is arranged on the pipeline.

[0026] A further improvement of the present invention is:

[0027] The settling tank comprises a settling tank body, a central tube is arranged at the upper part of the settling tank body, a water inlet pipe is connected to the upper side wall of the central tube, and the other end of the water inlet pipe passes through the settling tank body and is connected to the overflow outlet of the degassing tank; and / or,

[0028] An overflow weir is arranged on the upper part of the side wall of the settling tank body, the overflow weir is located above the water inlet pipe, and the overflow weir is connected to a water outlet main pipe; and / or,

[0029] A mud hopper is provided in the body of the sedimentation tank below the reflector, and a mud discharge port is provided at the bottom of the mud hopper. The mud discharge port is connected to the mud return port on the anoxic reactor body through a mud return pump.

[0030] A further improvement of the present invention is:

[0031] A reflector is provided in the sedimentation tank body near the bottom end of the central tube, and the reflector is in a conical structure; and / or,

[0032] An inclined tube assembly is arranged in the sedimentation tank body with the cylinder as the center. The inclined tube assembly is located below the water inlet pipe. The inclined tube assembly includes a multi-layer inclined tube combination arranged in the sedimentation tank body and centered on the central cylinder. Each layer of the inclined tube combination includes multiple inclined tubes. The multiple inclined tubes are evenly arranged along the circumference and form the same angle with the central axis.

[0033] A further improvement of the present invention is:

[0034] The ozone catalytic oxidation reactor comprises a reactor body, the upper part of the side wall of the reactor body is connected with a water inlet pipeline and a water outlet overflow weir, and the water outlet overflow weir is located below the water inlet pipeline; and / or,

[0035] An inner cylinder is arranged in the reactor body, the inner cylinder is filled with a catalyst, a water spraying structure is arranged in the reactor body and above the inner cylinder, and the water spraying structure is connected to a water inlet pipeline; and / or,

[0036] An ozone distributor is arranged at the bottom of the inner cylinder, and the ozone distributor is connected to an ozone generator arranged outside the reactor body through a pipeline.

[0037] The second aspect of the present invention provides a method for treating refinery wastewater, wherein the refinery wastewater is treated by using the refinery wastewater treatment device.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The invention provides a new process flow for oil refinery wastewater with a short process and device, and its specific advantages include:

[0040] a. Realize the equipment-based and closed treatment of refinery wastewater, save floor space and reduce on-site odor;

[0041] b. Realize short-process and low-cost treatment of refinery wastewater;

[0042] c. The effluent quality is stable and meets the standards, COD <30mg / L, TN <12mg / L, TP <0.5mg / L, ammonia nitrogen <5mg / L, petroleum <3mg / L, suspended solids <10mg / L, reaching the advanced level in the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a structural diagram of a refinery wastewater treatment system in an embodiment of the present invention;

[0044] Figure 2 is a schematic structural diagram of an anoxic fluidized bed reactor according to an embodiment of the present invention;

[0045] Figure 3 is a schematic structural diagram of an aerobic fluidized bed reactor in an embodiment of the present invention;

[0046] Figure 4 It is a schematic diagram of the structure of a settling tank in an embodiment of the present invention;

[0047] Figure 5 Schematic diagram of the structure of the ozone catalytic oxidation reactor in an embodiment of the present invention.

[0048] In the figure, 1, regulating buffer tank, 2, microbubble generator, 3, cyclone flotation separation tank, 4, three-phase separation tank, 5, MPE separator, 6, anoxic fluidized bed reactor, 601, anoxic reactor body, 602, anoxic water inlet, 603, nitrate liquid reflux port, 604, sludge reflux port, 605, liquid outlet, 606, guide tube, 607, submersible flow pusher, 7, aerobic fluidized bed reactor, 701, aerobic reactor body, 702, aerobic water inlet, 703, water outlet overflow port, 704, spray water annular pipe, 705, aerobic inner cylinder, 706, microporous aerator, 707, aeration pipe port, 708, filler, 709, spray water pipe, 8, aeration Air blower, 9. Nitrate liquid reflux pump, 10. Degassing tank, 11. Sedimentation tank, 1101. Sedimentation tank body, 1102. Center pipe, 1103. Water inlet pipe, 1104. Reflection plate, 1105. Inclined tube assembly, 1106. Overflow weir, 1107. Mud bucket, 12. Sludge reflux pump, 13. High-level coagulation reaction tank, 14. High-efficiency quicksand filter, 15. Ozone water inlet tank, 16. Ozone catalytic oxidation reactor, 1601. Reactor body, 1602. Water inlet pipeline, 1603. Outlet overflow weir, 1604. Inner cylinder, 1605. Spray water distribution structure, 1606. Ozone distributor, 17. Ozone generator, 18. Ozone tail gas destroyer. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0050] [Example 1]

[0051] like Figure 1 As shown, this embodiment provides a refinery wastewater treatment system, which includes an oil removal pretreatment unit, a biochemical treatment unit and a deep treatment unit connected in sequence according to the direction of water flow;

[0052] The oil removal pretreatment unit comprises a regulating buffer tank 1, a cyclone flotation separation tank 3 and an MPE separator 5 which are connected in sequence;

[0053] The biochemical treatment unit includes an anoxic fluidized bed reactor 6, an aerobic fluidized bed reactor 7 and a settling tank 11 which are connected in sequence;

[0054] The deep treatment unit includes a high-level coagulation reaction tank 13, a high-efficiency quicksand filter 14 and an ozone catalytic oxidation reactor 16 which are connected in sequence.

[0055] The wastewater from the oil refinery, after being adjusted and evenly placed in the adjustment buffer tank 1, enters the cyclone flotation separation tank 3 and the MPE separator 5 in sequence to remove most of the petroleum in the wastewater and meet the oil content requirements of the subsequent biochemical treatment unit; the wastewater after oil removal enters the biochemical treatment unit, and passes through the anoxic fluidized bed reactor 6 and the aerobic fluidized bed reactor 7 in sequence to remove most of the organic matter, ammonia and nitrogen, and total nitrogen in the water; the effluent of the biochemical treatment unit enters the high-level coagulation reaction tank 13 and the high-efficiency quicksand filter 14 of the deep treatment unit, on the one hand to remove the residual particulate matter in the wastewater and reduce the consumption of ozone in the subsequent process, on the other hand to remove the total phosphorus in the wastewater, and the sand filtered effluent enters the ozone catalytic oxidation reactor 16 to further remove the difficult-to-degrade organic matter in the wastewater and ensure that the COD of the effluent meets the standard.

[0056] [Example 2]

[0057] The oil removal pretreatment unit comprises a regulating buffer tank 1, a cyclone flotation separation tank 3 and an MPE separator 5 which are connected in sequence.

[0058] Among them, a microbubble generator 2 is also connected between the regulating buffer tank 1 and the cyclone flotation separation tank 3. A water inlet pump is provided on the pipeline connecting the water outlet of the regulating buffer tank 1 and the water inlet of the microbubble generator 2. The water inlet pump lifts the regulated and evenly placed sewage in the regulating buffer tank 1 to the microbubble generator 2. The oily sewage first quickly dissolves gas in the microbubble generator 2, so that the oily sewage and microbubbles are fully mixed to form an "oil droplet-bubble adhesion body". The oily sewage containing a large amount of "oil droplet-bubble adhesion bodies" enters the cyclone flotation separation tank 3 in a tangential direction. In the process, a weak cyclone is formed; due to the large difference in gas-liquid density, the relatively low cyclone centrifugal force can make the "oil droplet-bubble adhesion body" quickly converge near the axis line of the cyclone flotation separation tank 3. Under the dual effects of buoyancy and centrifugal force, the "oil droplet-bubble adhesion body" continuously floats up, forming a floating slag layer on the upper part of the liquid surface, and is discharged from the oil discharge port on the upper part of the tank body. The gas in the upper gas phase space in the tank body is discharged from the exhaust port together with the "oil droplet-bubble adhesion body" out of the tank, and the water phase moves to the bottom of the tank and is discharged from the drain port at the bottom of the tank body into the MPE separator 5.

[0059] The oil discharge port of the cyclone flotation separation tank 3 is connected to a three-phase separation tank 4. After the oily wastewater is treated by the cyclone flotation separation tank 1, the discharged oil phase will also carry some water and gas. The oil phase needs to enter the three-phase separation tank 4 for further separation, and finally achieve the three-phase separation of scum, water and gas. The scum and gas separated by the three-phase separation tank 4 will be directly discharged for subsequent treatment, and the water phase will first be discharged into the regional pit or sump by gravity flow, and then lifted to the regulating buffer tank 1 by a pump; the discharge port of the cyclone flotation separation tank 3 is connected to the MPE separator 5 through a pipeline.

[0060] Before the oily wastewater enters the cyclone flotation separation tank 1, PAC and PAM are added to the pipeline in sequence. According to the influent water volume and water quality, the addition concentration of PAM is 3-8ppm, and the addition concentration of PAC is 80-120ppm. The residence time of the oily wastewater in the cyclone flotation separation tank is 15-30min.

[0061] Among them, the regulating buffer tank 1, the microbubble generator 2, the cyclone flotation separation tank 3 and the three-phase separation tank 4 all adopt existing technical equipment, which will not be described in detail here.

[0062] [Example 3]

[0063] The MPE separator 5 is a cylindrical vertical container with upper and lower circular heads. The MPE separator 5 is filled with MPE particle beds and CFC fiber modules in sequence from top to bottom.

[0064] MPE particles are a type of high temperature resistant and corrosion resistant granular medium with better hydrophilicity or lipophilicity. Its bed is composed of two different hydrophilic and hydrophobic MPE particles, one of which is lipophilic and hydrophobic particles, and the other is hydrophilic and lipophobic particles, taking into account both oil removal and solid removal. The technical core of MPE oil removal lies in agglomeration, that is, using physical methods to turn small oil droplets into large oil droplets and separate them under the action of gravity. The principle is to let the oily wastewater pass through the hydrophilic and lipophilic MPE particle bed from top to bottom. The emulsified oil droplets with smaller particle size in the water collide, adhere, aggregate, fuse, grow on the surface of a single lipophilic and hydrophobic particle and between multiple lipophilic and hydrophobic particles, and are finally released. The separation of viscous suspended matter and solid particle impurities by MPE particles mainly relies on the adsorption and interception effect of the bed. For example, when colloid particles and insoluble salts flow through the MPE bed, they are intercepted on the upper surface because their particle size is larger than the bed gap. When impurities with smaller particle sizes pass through the medium bed, they will be adsorbed by the MPE particles with tiny pores on the surface, or adsorbed by the more viscous oil layer or oil bed, and finally separated together with the oil phase.

[0065] The basic principle of the CFC fiber module is the rapid aggregation and separation induced by the precursor oil film of finely dispersed oil on the surface of the oleophilic fiber, and the polar force demulsification of the emulsified oil at the intersection of the hydrophilic / hydrophobic heterogeneous fibers.

[0066] The residence time of the oily wastewater in the MPE separator 5 is 5 to 15 minutes.

[0067] The water quality of the sewage after being treated by the oil removal pretreatment unit of the present invention is shown in Table 1.

[0068] Table 1 Sewage quality after treatment by oil removal pretreatment unit

[0069]

[0070] The oil removal pretreatment unit adopts cyclone flotation + coalescence oil removal method. Compared with the traditional oil separation + flotation process, on the one hand, it improves the removal efficiency of emulsified oil and can also remove dispersed oil in sewage. On the other hand, the grease trap is replaced by an installed cyclone flotation equipment, which reduces the footprint, improves the sealing level, and reduces the odor on site.

[0071] [Example 4]

[0072] The biochemical treatment unit includes an anoxic fluidized bed reactor 6, an aerobic fluidized bed reactor 7 and a settling tank 11 connected in sequence. The biochemical treatment unit uses an A / O fluidized bed reactor. Compared with the traditional A / O activated sludge method, a) the volume load of the pollutants in the reaction is increased; b) the vertical reactor replaces the traditional biochemical reaction tank, which reduces the land occupation, improves the sealing level, and reduces the odor on site.

[0073] The principle of sewage treatment by the anoxic fluidized bed reactor 6 and the aerobic fluidized bed reactor 7 is an A / O process combining the activated sludge process and the biofilm process. Denitrification is carried out in the anoxic fluidized bed reactor 6, and nitrification is carried out in the aerobic fluidized bed reactor 7 to remove ammonia nitrogen and COD.

[0074] like Figure 2 As shown, the anoxic fluidized bed reactor 6 includes an anoxic reactor body 601, an anoxic water inlet 602, a nitrate liquid return port 603 and a sludge return port 604 are arranged at the lower part of the side wall of the anoxic reactor body 601, a liquid outlet 605 is arranged at the upper part of the side wall, and the liquid outlet 605 is an overflow outlet. A guide tube 606 is arranged in the anoxic reactor body 601, and a submersible flow propeller 607 is installed in the guide tube 606 to fully mix the sewage, the return sludge and the return nitrate liquid. The sewage, the return sludge and the return nitrate liquid all enter from the lower part of the side wall of the anoxic reactor body 601, and the effluent overflows from the upper liquid outlet 605 into the aerobic fluidized bed reactor 7. The top of the anoxic reactor body 601 is provided with a waste gas port for waste gas collection.

[0075] Anoxic fluidized bed reactor 6 single unit processing scale 200m 3 / h, hydraulic retention time 3-6h, nitrate nitrogen volume load 0.3-0.55kgNOx / m 3 d. The anoxic fluidized bed reactor equipment is equipped with dissolved oxygen concentration and pH monitoring instruments to control the dissolved oxygen to be lower than 0.5 mg / L and the pH to be between 6.8-7.8.

[0076] [Example 5]

[0077] like Figure 3As shown, the aerobic fluidized bed reactor 7 is a cylindrical container, comprising an aerobic reactor body 701, an aerobic water inlet 702 is provided at the lower part of the side wall of the aerobic reactor body 701, and a water outlet overflow port 703 is provided at the upper part;

[0078] A plurality of aerobic inner cylinders 705 are arranged in the aerobic reactor body 701. The aerobic inner cylinders 705 are internally through-fired and vertically arranged in the aerobic reactor body 701. The aerobic inner cylinders 705 are about 9 meters high. A plurality of microporous aerators 706 are arranged below each aerobic inner cylinder 705. Preferably, 19 microporous aerators 706 are symmetrically arranged in each aerobic inner cylinder 705 to provide oxygen required for aerobic operation through aeration and provide power for fluidizing the filler.

[0079] A plurality of aeration pipe openings 707, preferably 6, are evenly provided on the lower side wall of the aerobic reactor body 701. The microporous aerator 706 is connected to one end of the aeration pipe, and the other end of the aeration pipe passes through the aeration pipe opening 707 and extends out of the aerobic reactor body 701 and is connected to the aeration fan 8 through a pipeline.

[0080] A filler 708 is arranged in the aerobic inner cylinder 705 . The filler 708 is a suspended filler and will be suspended in water under aeration conditions. Filters are provided at the bottom and top of the aerobic inner cylinder 705 to prevent the filler 708 from falling out of the aerobic inner cylinder 705 .

[0081] A spray water annular pipe 704 is arranged at the upper inner part of the aerobic reactor body 701, and a plurality of small holes are evenly opened at the bottom of the spray water annular pipe 704. A plurality of spray water pipes 709, preferably 4, are arranged at the top of the aerobic reactor body 701. The spray water annular pipe 704 and the spray water pipe 709 are both connected to an external water pipe for defoaming the liquid surface.

[0082] The top of the aerobic reactor body 701 is provided with an exhaust port for exhaust gas collection, and a filler loading and unloading port is also provided for loading and unloading fillers.

[0083] The liquid outlet 605 of the anoxic fluidized bed reactor 6 is connected to the aerobic water inlet 702 of the aerobic fluidized bed reactor 7 through a pipeline, and a sodium carbonate dosing point is provided on the pipeline to supplement the alkalinity required for the nitrification reaction.

[0084] Aerobic fluidized bed reactor: single unit processing scale 200m 3 / h, hydraulic retention time 10h, with suspended filler. COD volume load 0.9-1.3kgCOD / m 3 d, ammonia nitrogen volume load 0.12-0.21kgNH 3 / m 3d, sludge concentration 1500-2500mg / L, nitrate liquid return ratio 300-500%, activated sludge return ratio 40-60%. The anoxic fluidized bed reactor equipment is equipped with dissolved oxygen concentration, pH and temperature monitoring instruments to control the dissolved oxygen to not less than 2.0mg / L, pH between 7.5-8.5, and temperature not higher than 40℃.

[0085] The height of the anoxic reactor body is not less than 12 meters, and the height of the aerobic reactor body is not less than 11 meters. Because of the gravity flow liquid level control, during normal operation, the liquid level depths of the anoxic fluidized bed reactor and the aerobic fluidized bed reactor are stabilized at 12 meters and 11 meters respectively to improve the efficiency of the biochemical reaction. The depth of the general water tank structure in the existing sewage treatment plant does not exceed 7 meters. The present invention increases the bottom pressure by increasing the liquid level depth, enhances the gas-liquid mass transfer, and improves the efficiency of the biochemical reaction.

[0086] The refinery wastewater is treated in the oil removal pretreatment unit and then enters the anoxic fluidized bed reactor 6 and the aerobic fluidized bed reactor 7 for treatment. The effluent quality is shown in Table 2.

[0087] Table 2

[0088]

[0089] [Example 6]

[0090] like Figure 1 As shown, a degassing tank 10 is also connected between the aerobic fluidized bed reactor 7 and the sedimentation tank 11. Because the aerobic fluidized bed reactor 7 is used upstream, and the air aeration head of the aerobic fluidized bed reactor 7 is located relatively deep, the soda-water mixing effect is good, and the small bubbles dissolved in the water will affect the subsequent mud-water separation. Therefore, before the sludge is settled, the degassing tank 10 is set to release the small bubbles dissolved in the water.

[0091] The degassing tank 10 comprises a degassing tank body, a water inlet is arranged on the upper part of the side wall of the degassing tank body, an overflow outlet is arranged on the side wall opposite to the water inlet, the position of the overflow outlet is lower than the position of the water inlet, a water inlet pipe is connected to the water inlet, one end of the water inlet pipe is located outside the degassing tank body, and the other end extends into the degassing tank body and is a 90° elbow with an opening downward to prevent water from short-flowing from the overflow outlet on the other side; a nitrate liquid flow outlet is arranged at the bottom of the degassing tank body, the nitrate liquid flow outlet is connected to the nitrate liquid flow outlet 603 on the anoxic reactor body 601 through a pipeline, and a nitrate liquid reflux pump 9 is arranged on the pipeline, part of the sewage is lifted and refluxed into the anoxic fluidized bed reactor 6 by the nitrate liquid reflux pump 9, and the remaining sewage flows to the downstream sedimentation tank 11 by gravity from the overflow outlet, and a waste gas outlet is arranged at the top of the degassing tank 10 for waste gas collection.

[0092] The sewage stays in the degassing tank 10 for about 2-6 minutes.

[0093] [Example 7]

[0094] like Figure 4 As shown, the settling tank 11 includes a settling tank body 1101, and a central tube 1102 is arranged at the upper part of the settling tank body 1101. The central tube 1102 is composed of a hollow cylinder at the upper part and a hollow horn cylinder at the lower part, which is small at the upper part and large at the lower part. A water inlet pipe 1103 is connected to the side wall of the hollow cylinder at the upper part of the central tube 1102. The other end of the water inlet pipe 1103 passes through the outside of the settling tank body 1101 and is connected to the overflow outlet of the degassing tank 10. A water inlet pipe 1103 is arranged near the bottom end of the central tube 1102 in the settling tank body 1101. There is a reflecting plate 1104, which has a conical structure. An inclined tube assembly 1105 is arranged in the sedimentation tank body 1101 with the central tube 1102 as the center. The inclined tube assembly 1105 is located below the water inlet pipe 1103. An overflow weir 1106 is arranged on the upper part of the side wall of the sedimentation tank body 1101. The overflow weir 1106 is located above the water inlet pipe 1103. The overflow weir 1106 is connected to the water outlet main pipe. A mud bucket 1107 is arranged in the sedimentation tank body 1101 below the reflecting plate 1104.

[0095] The inclined tube assembly 1105 includes a multi-layer inclined tube combination arranged in the sedimentation tank body and centered on the central tube 1102. Each layer of the inclined tube combination includes multiple inclined tubes. The multiple inclined tubes are evenly arranged along the circumference and form the same angle with the central axis. That is to say, the central axes of the inclined tubes on the same layer are located on the same busbar of the cone.

[0096] The sewage treated by the degassing tank 10 enters the central tube 1102 of the sedimentation tank 11 through the water inlet pipe 1103. When the inlet water flows downward along the central tube 1102 and contacts the reflector 1104, the sewage and suspended matter in the water will change the direction of movement due to the conical structure of the reflector 1104. Due to the density difference, the suspended matter with high density is more likely to slide down along the surface of the reflector 1104 to the mud bucket 1107, which is beneficial to the solid-liquid separation, and the sewage will pass through the inclined tube assembly 1105 upward. The setting of the inclined tube assembly 1105 increases the surface load of the sedimentation tank 11. The sewage passing through the inclined tube assembly 1105 overflows and enters the main outlet pipe, while the particulate matter settles downward along the inner wall of the inclined tube assembly 1105 to the mud bucket 1107 of the sedimentation tank 11.

[0097] A sludge pipe port is provided at the bottom of the mud hopper 1107, and the sludge pipe port is connected to the sludge return port 604 on the anoxic reactor body 601 through the sludge return pump 12. After being degassed by the degassing tank 10, the sewage enters the sedimentation tank 11 for mud and water separation. After separation, the sewage enters the downstream treatment facility, and the sludge is returned to the anoxic fluidized bed reactor 6, and the remaining sludge is discharged. A waste gas port is provided on the top of the sedimentation tank body 1101 for waste gas collection.

[0098] The residence time of the sedimentation tank 11 is 2 hours, and the surface hydraulic load is 2.0m 3 / m 2 h.

[0099] [Example 8]

[0100] The deep treatment unit includes a high-level coagulation reaction tank 13, a high-efficiency quicksand filter 14 and an ozone catalytic oxidation reactor 16 connected in sequence. The deep treatment part adopts coagulation, sand filtration + ozone catalytic oxidation, a) ozone catalytic oxidation ensures the stability of effluent COD; b) the quicksand filter replaces the traditional sand filter tank, and the ozone catalytic oxidation reactor replaces the traditional ozone catalytic oxidation reaction tank, which reduces the land occupation, improves the sealing level, and reduces the odor on site.

[0101] The high-level coagulation reaction tank 13 includes a body, a water inlet is arranged at the bottom of the side wall of the body, a water outlet is arranged at the upper part of the side wall of the body opposite to the water inlet, and a stirrer is installed in the body. When sewage enters the high-level coagulation reaction tank, a coagulant (usually PAC) is added to the reaction tank through a dosing pump, and a coagulation reaction occurs with the help of the stirrer, reacting with suspended matter and phosphate in the sewage to form flocculent precipitation. Coagulation time: 6-10min, dosage: 20mg / L PAC solution (Al 2 O 3 concentration is 20%).

[0102] The high-efficiency quicksand filter 14 adopts existing technical equipment, which will not be described in detail here. The sewage enters the high-efficiency quicksand filter 14 from the bottom, flows upward through the filter bed, and the impurities in the sewage are continuously intercepted and adsorbed. The filtrate finally overflows from the top of the filter and is sent to the downstream ozone catalytic oxidation reactor 16 through a pipeline.

[0103] [Example 9]

[0104] like Figure 5 As shown, the ozone catalytic oxidation reactor 16 includes a reactor body 1601, and the upper part of the side wall of the reactor body 1601 is connected with a water inlet pipeline 1602 and a water outlet overflow weir 1603, and the water outlet overflow weir 1603 is located below the water inlet pipeline 1602;

[0105] An inner cylinder 1604 is arranged in the reactor body 1601, and a catalyst is filled in the inner cylinder 1604. A spray water distribution structure 1605 is arranged in the reactor body 1601 and above the inner cylinder. The spray water distribution structure 1605 is connected to the water inlet pipeline 1602, wherein the spray water distribution structure 1605 is an annular tube, and a plurality of evenly distributed nozzles with downward nozzles are arranged on the annular tube;

[0106] An ozone distributor 1606 is provided at the bottom of the inner cylinder 1604, and the ozone distributor 1606 is connected to the ozone generator 17 provided outside the reactor body 1602 through a pipeline. The ozone distributor 1606 includes an ozone tube, and the ozone tube is provided with a plurality of ozone injection ports that are evenly distributed and face upward.

[0107] The sewage enters the spray water distribution structure 1605 from the water inlet pipe 1602, and the water is evenly distributed through the spray water distribution structure 1605, and enters the inner cylinder 1604, where it comes into contact with the ozone entering the inner cylinder 1604 from the bottom under the action of the catalyst and undergoes an oxidation reaction. The sewage passes through the inner cylinder 1604 from top to bottom, and then passes through the gap between the reactor body 1601 and the inner cylinder 1604 from bottom to top, and finally overflows from the upper outlet overflow weir 1603.

[0108] An exhaust port is provided at the top of the reactor body 1601, and the ozone that does not participate in the reaction enters the downstream ozone tail gas destroyer 18 through the exhaust gas pipeline.

[0109] The upper and / or lower part of the side wall of the reactor body 1601 is provided with a catalyst loading and unloading port.

[0110] An ozone water inlet tank 15 is also provided between the high-efficiency quicksand filter 14 and the ozone catalytic oxidation reactor 16. From the height point of view, the water outlet from the high-efficiency quicksand filter 14 cannot flow to the ozone catalytic oxidation reactor 16 by itself and needs to be lifted by a pump. Therefore, an ozone water inlet tank 15 is provided to temporarily store the water outlet from the high-efficiency quicksand filter 14 and lift it into the ozone catalytic oxidation reactor 16 by an ozone water inlet pump.

[0111] [Example 10]

[0112] This embodiment also provides a method for treating refinery wastewater, which uses the refinery wastewater treatment device described in Examples 1-9 to treat the refinery wastewater.

[0113] The method of the present invention is suitable for the short-process and device-based treatment process of refinery wastewater, with a treatment capacity of 400m 3 / h, influent COD<800mg / L, ammonia nitrogen<100mg / L, TN<150mg / L, suspended solids<300mg / L, petroleum<600mg / L, TP<5mg / L, and effluent meets the expected effect.

[0114] Compared with the prior art, under the condition that the water quality of influent and effluent is the same, the area occupied by the refinery wastewater treatment system of the present invention is significantly reduced. The anoxic fluidized bed reactor of the present invention occupies about 180m 2 The aerobic fluidized bed reactor and degassing tank together occupy about 600m 2 The sedimentation tank covers an area of ​​about 320m 2 The ozone catalytic oxidation reactor occupies an area of ​​about 90m2 .

[0115] In the prior art, the anoxic pool occupies an area of ​​about 600m 2 The aerobic pool covers an area of ​​about 1200m 2 The sedimentation tank covers an area of ​​about 620m 2 The ozone catalytic oxidation reaction pool covers an area of ​​140m 2 .

[0116] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0117] In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0118] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A refinery wastewater treatment system, characterized in that: According to the direction of water flow, it includes an oil removal pretreatment unit, a biochemical treatment unit and a deep treatment unit connected in sequence; The oil removal pretreatment unit comprises a regulating buffer tank, a cyclone flotation separation tank and an MPE separator connected in sequence; The biochemical treatment unit comprises an anoxic fluidized bed reactor, an aerobic fluidized bed reactor and a settling tank which are connected in sequence; The deep treatment unit comprises a high-level coagulation reaction tank, a high-efficiency quicksand filter and an ozone catalytic oxidation reactor which are connected in sequence.

2. The refinery wastewater treatment system according to claim 1, characterized in that: A micro-bubble generator is also connected between the regulating buffer tank and the cyclone flotation separation tank, and a water inlet pump is provided on the pipeline connecting the water outlet of the regulating buffer tank and the water inlet of the micro-bubble generator.

3. The refinery wastewater treatment system according to claim 2, characterized in that: The anoxic fluidized bed reactor comprises an anoxic reactor body, an anoxic water inlet, a nitrate liquid return port and a sludge return port are arranged at the lower part of the side wall of the anoxic reactor body, and a liquid outlet is arranged at the upper part of the side wall; and / or, A guide tube is arranged in the anoxic reactor body, and a submersible flow propeller is installed in the guide tube to fully mix the sewage, the return sludge and the return nitrate liquid.

4. The refinery wastewater treatment system according to claim 3, characterized in that: The aerobic fluidized bed reactor comprises an aerobic reactor body, wherein the lower part of the side wall of the aerobic reactor body is provided with an aerobic water inlet, and the upper part is provided with a water outlet overflow port; and / or, A plurality of aerobic inner cylinders are arranged in the aerobic reactor body, and fillers are arranged in the aerobic inner cylinders. A plurality of microporous aerators are arranged under each aerobic inner cylinder, and the microporous aerators are connected to an aeration fan located outside the aerobic reactor body through a pipeline.

5. The refinery wastewater treatment system according to claim 4, characterized in that: A spray water annular pipe is arranged at the upper part of the aerobic reactor body, and a plurality of small holes are evenly arranged at the bottom of the spray water annular pipe; A plurality of spray water pipes are arranged on the top of the aerobic reactor body, and the spray water annular pipe and the spray water pipes are both connected to an external water pipe for defoaming the liquid surface.

6. The refinery wastewater treatment system according to claim 5, characterized in that: A degassing tank is further connected between the aerobic fluidized bed reactor and the settling tank; and / or, The degassing tank comprises a degassing tank body, a water inlet is arranged at the upper part of the side wall of the degassing tank body, an overflow outlet is arranged at the side opposite to the water inlet, and the position of the overflow outlet is lower than the position of the water inlet; and / or, A nitrate liquid outlet is arranged at the bottom of the degassing tank body, and the nitrate liquid outlet is communicated with the nitrate liquid outlet on the anoxic reactor body through a pipeline, and a nitrate liquid reflux pump is arranged on the pipeline.

7. The refinery wastewater treatment system according to claim 6, characterized in that: The settling tank comprises a settling tank body, a central tube is arranged at the upper part of the settling tank body, a water inlet pipe is connected to the upper side wall of the central tube, and the other end of the water inlet pipe passes through the settling tank body and is connected to the overflow outlet of the degassing tank; and / or, An overflow weir is arranged on the upper part of the side wall of the settling tank body, the overflow weir is located above the water inlet pipe, and the overflow weir is connected to a water outlet main pipe; and / or, A mud hopper is provided in the body of the sedimentation tank below the reflector, and a mud discharge port is provided at the bottom of the mud hopper. The mud discharge port is connected to the mud return port on the anoxic reactor body through a mud return pump.

8. The refinery wastewater treatment system according to claim 7, characterized in that: A reflector is provided in the sedimentation tank body near the bottom end of the central tube, and the reflector is in a conical structure; and / or, An inclined tube assembly is arranged in the sedimentation tank body with the cylinder as the center. The inclined tube assembly is located below the water inlet pipe. The inclined tube assembly includes a multi-layer inclined tube combination arranged in the sedimentation tank body and centered on the central cylinder. Each layer of the inclined tube combination includes multiple inclined tubes. The multiple inclined tubes are evenly arranged along the circumference and form the same angle with the central axis.

9. The refinery wastewater treatment system according to claim 8, characterized in that: The ozone catalytic oxidation reactor comprises a reactor body, the upper part of the side wall of the reactor body is connected with a water inlet pipeline and a water outlet overflow weir, and the water outlet overflow weir is located below the water inlet pipeline; and / or, An inner cylinder is arranged in the reactor body, the inner cylinder is filled with a catalyst, a water spraying structure is arranged in the reactor body and above the inner cylinder, and the water spraying structure is connected to a water inlet pipeline; and / or, An ozone distributor is arranged at the bottom of the inner cylinder, and the ozone distributor is connected to an ozone generator arranged outside the reactor body through a pipeline.

10. A method for treating refinery wastewater, characterized in that: The refinery wastewater is treated by using the refinery wastewater treatment device as described in any one of claims 1 to 9.

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