Treatment system for comprehensive waste liquid of oil field

Abstract

The utility model provides a treatment system for comprehensive waste liquid of an oil field. The treatment system comprises a waste liquid regulating tank, a demulsification coagulation pry, a primary mud-water separation pry, an intermediate water tank, an iron-carbon micro-electrolysis reaction pry, a Fenton coagulation pry, a secondary mud-water separation pry, a primary biochemical pry, an inclined plate precipitation pry, a secondary biochemical pry, an activated carbon adsorption pry and a produced water collecting tank, and a water outlet of the produced water collecting tank is respectively connected with the secondary biochemical pry and the activated carbon adsorption pry through pipelines. According to the petrochemical wastewater treatment device, four processes of iron-carbon micro-electrolysis, Fenton advanced oxidation, primary biochemical treatment and secondary biochemical treatment are combined, so that petrochemical wastewater with higher COD (Chemical Oxygen Demand) index can be treated; and skid-mounted equipment is adopted, so that the device is convenient to move, and the petroleum slurry wastewater can be conveniently treated by adopting a service mode.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of waste liquid treatment, especially relate to a treatment system of oilfield comprehensive waste liquid. BACKGROUND

[0002] With the continuous deepening of oilfield development, the oilfield comprehensive waste liquid includes oily sludge generated in crude oil exploitation and treatment, high-alkaline waste liquid generated in crude oil equipment cleaning, and chemical waste liquid generated in chemical production. The wastewater has high pH value, high COD, high colority, high solid content and high odor, and is extremely difficult to treat. The influence on the environment is increasingly valued, and the waste liquid treatment situation is increasingly severe. With the more stringent requirements of the state on environmental protection, in order to meet the requirements of oilfield development on water quality, from the perspective of environmental protection and oilfield production management, waste liquid comprehensive treatment and recycling should be realized, harmless treatment of oilfield waste liquid should be realized, and the treated waste liquid should be put into the pipe network system and then treated, so as to achieve the purpose of environmental protection.

[0003] However, the composition of the chemical waste liquid is very complex at present, because different demulsifiers, stabilizers and floatation agents are added in the oilfield exploitation process and the crude oil processing process, the water quality is unstable, the organic matter is difficult to treat, and the salinity and toxic element content are very high.

[0004] The biological treatment method has the characteristics of convenient operation, high economic benefit and no secondary pollution. CONTENT OF THE UTILITY MODEL

[0005] Therefore, the utility model aims at providing a treatment system of oilfield comprehensive waste liquid. Firstly, demulsification is carried out on the wastewater through physical and chemical action, the biodegradability of the wastewater is improved through advanced oxidation, finally, the salt-tolerant bacteria strains with high-efficiency degradation of organic matter are separated through the changes of the microbial species and the colony structure of the biochemical system, so that the COD, suspended solids and pH value of the treated waste liquid can meet the requirements of external drainage.

[0006] In order to achieve the above purpose, the technical scheme of the utility model is as follows:

[0007] A treatment system of oilfield comprehensive waste liquid, comprising a waste liquid adjusting tank, a demulsification and coagulation pry, a first sludge-water separation pry, an intermediate tank, an iron-carbon micro-electrolysis reaction pry, a Fenton coagulation pry, a second sludge-water separation pry, a first biochemical pry, an inclined plate sedimentation pry, a second biochemical pry, an activated carbon adsorption pry and a water production collection tank.

[0008] The effluent regulating tank is connected with the inlet of the demulsification coagulation sled, the outlet of the demulsification coagulation sled is connected with the inlet of the primary sludge-water separation sled, the outlet of the primary sludge-water separation sled is connected with the inlet of the intermediate water tank, the outlet of the intermediate water tank is connected with the inlet of the iron-carbon micro-electrolysis reaction sled, the outlet of the iron-carbon micro-electrolysis reaction sled is connected with the inlet of the Fenton coagulation sled, the outlet of the Fenton coagulation sled is connected with the inlet of the secondary sludge-water separation sled, the outlet of the secondary sludge-water separation sled is connected with the inlet of the primary biochemical sled, the outlet of the primary biochemical sled is connected with the inlet of the inclined plate sedimentation sled, the outlet of the inclined plate sedimentation sled is connected with the inlet of the secondary biochemical sled, the outlet of the secondary biochemical sled is connected with the inlet of the activated carbon adsorption sled, and the outlet of the activated carbon adsorption sled is connected with the inlet of the water production collection tank.

[0009] Further, the outlet of the water production collection tank is connected with the secondary biochemical sled and the activated carbon adsorption sled respectively through pipelines.

[0010] Further, the concentrated sludge separated by the inclined plate sedimentation sled is returned to the primary biochemical sled.

[0011] Further, the physical and chemical dosing sled is connected with the demulsification coagulation sled, the primary sludge-water separation sled, the iron-carbon micro-electrolysis reaction sled, the Fenton coagulation sled, the secondary sludge-water separation sled, the primary biochemical sled and the secondary biochemical sled respectively.

[0012] Further, the primary biochemical sled comprises a primary biochemical regulating tank, an ABR anaerobic reactor and a contact oxidation tank.

[0013] Further, the secondary biochemical sled comprises a secondary biochemical regulating tank, an anoxic tank and an MBR tank.

[0014] Further, the demulsification coagulation sled comprises a demulsification coagulation reactor, a lifting pump, a stirrer, a PLC control cabinet and instruments, and the instruments include an online pH meter and an online liquid level meter.

[0015] Further, the iron-carbon micro-electrolysis reaction sled comprises two iron-carbon reactors and two stirring fans.

[0016] Further, the Fenton coagulation sled comprises a Fenton coagulation reactor, a lifting pump, a stirrer, a PLC control cabinet and instruments, and the instruments include an online pH meter and an online liquid level meter.

[0017] Further, the primary biochemical sled is connected with a primary biochemical fan sled.

[0018] Further, the secondary biochemical sled is connected with a secondary biochemical fan sled.

[0019] MBR also called membrane bio-reactor.

[0020] Compared with the prior art, the oil field comprehensive waste liquid treatment system has the following advantages:

[0021] The four processes of iron-carbon micro-electrolysis, Fenton advanced oxidation, primary and secondary biochemical treatment are combined, so that petrochemical wastewater with high COD index can be treated.

[0022] The pry-mounted equipment is convenient to move, and can be used to treat oil slurry wastewater in a service mode. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The accompanying drawings should not be construed as an inappropriate limitation to the present application. In the drawings:

[0024] Figure 1 The structure diagram of the oil field comprehensive waste liquid treatment system according to the embodiments of the present application.

[0025] Explanation of reference signs:

[0026] 1-waste liquid conditioning tank, 2-demulsification and coagulation pry, 3-primary sludge-water separation pry, 4-intermediate water tank, 5-iron-carbon micro-electrolysis reaction pry, 6-Fenton coagulation pry, 7-secondary sludge-water separation pry, 8-primary biochemical pry, 9-inclined plate sedimentation pry, 10-secondary biochemical pry, 11-activated carbon adsorption pry, and 12-water production collection tank. DETAILED DESCRIPTION

[0027] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0028] In the description of the utility model, it is necessary to understand that the orientation or positional relation indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or positional relation shown based on the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0029] In the description of the utility model, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood through specific circumstances.

[0030] The utility model will be described in detail below with reference to the drawings and in combination with embodiments.

[0031] A kind of oilfield comprehensive waste liquid processing system, including waste liquid regulating pool 1, demulsification coagulation pry 2, primary sludge-water separation pry 3, intermediate water pool 4, iron-carbon micro-electrolysis reaction pry 5, fenton coagulation pry 6, secondary sludge-water separation pry 7, primary biochemical pry 8, inclined plate sedimentation pry 9, secondary biochemical pry 10, activated carbon adsorption pry 11, water production collection tank 12;

[0032] The effluent regulating tank 1 is connected with the water inlet of the demulsification coagulation sled 2, the water outlet of the demulsification coagulation sled 2 is connected with the water inlet of the primary sludge-water separation sled 3, the water outlet of the primary sludge-water separation sled 3 is connected with the water inlet of the intermediate water tank 4, the water outlet of the intermediate water tank 4 is connected with the water inlet of the iron-carbon micro-electrolysis reaction sled 5, the water outlet of the iron-carbon micro-electrolysis reaction sled 5 is connected with the water inlet of the Fenton coagulation sled 6, the water outlet of the Fenton coagulation sled 6 is connected with the water inlet of the secondary sludge-water separation sled 7, the water outlet of the secondary sludge-water separation sled 7 is connected with the water inlet of the primary biochemical sled 8, the water outlet of the primary biochemical sled 8 is connected with the water inlet of the inclined plate sedimentation sled 9, the water outlet of the inclined plate sedimentation sled 9 is connected with the water inlet of the secondary biochemical sled 10, the water outlet of the secondary biochemical sled 10 is connected with the water inlet of the activated carbon adsorption sled 11, and the water outlet of the activated carbon adsorption sled 11 is connected with the water inlet of the produced water collecting tank 12.

[0033] The water outlet of the produced water collecting tank 12 is connected with the secondary biochemical sled 10 and the activated carbon adsorption sled 11 through pipelines.

[0034] The physical and chemical dosing sled is connected with the demulsification coagulation sled 2, the primary sludge-water separation sled 3, the iron-carbon micro-electrolysis reaction sled 5, the Fenton coagulation sled 6, the secondary sludge-water separation sled 7, the primary biochemical sled 8 and the secondary biochemical sled 10 respectively.

[0035] The effluent regulating tank 1 comprises a stirrer and a self-suction centrifugal pump, and the chemical waste liquid is collected and the water quality and quantity are adjusted. When the water quantity in the effluent regulating tank 1 reaches a certain volume, the production waste water is intermittently improved and treated. The improved waste water is transported to the demulsification coagulation sled 2 for physical and chemical pretreatment. The stirrer is arranged in the effluent regulating tank 1 to prevent solid deposition and to fully mix the waste water.

[0036] The demulsification coagulation sled 2 comprises a demulsification coagulation reactor, a lifting pump, a stirrer, a PLC control cabinet and instruments, and the instruments comprise an online pH meter and an online liquid level meter. The demulsification coagulation sled 2 has the functions of demulsification, pH adjustment, coagulation, flocculation, mixed liquid collection and filtrate collection, and comprises a stirrer, a lifting pump, an online pH meter, an online liquid level, and a carbon steel reactor with an internal glass steel anticorrosion layer. Each reaction unit has a hydraulic retention time of 1 h. By adding a demulsifier, the tiny oil droplets in the oil-in-water emulsion in the chemical waste liquid are released to achieve the effect of demulsification.

[0037] The primary sludge-water separation pry 3 contains a high-pressure diaphragm plate-and-frame filter press, a squeezing system and a sludge conveying system. Since the solid content in the waste liquid is high, in order to reduce the solid-phase load of the subsequent water treatment unit and ensure the good operation of the subsequent process, most of the solid phase is made into a mud cake and transported out through the primary sludge-water separation pry 3, and the liquid phase enters the intermediate water pool for further treatment.

[0038] The intermediate water pool 4 is self-flowed into the intermediate water pool 4 after the pretreatment of the chemical waste liquid. Acid is added to adjust the pH of the wastewater to 3. The intermediate water pool 4 is made of carbon steel, and a liquid level meter is arranged in the pool body to adjust the liquid level height of the pool body.

[0039] The iron-carbon micro-electrolysis reaction pry 5 contains two iron-carbon reactors and two stirring fans, and each iron-carbon reactor needs to be filled with 8 tons of iron-carbon filler. The iron-carbon micro-electrolysis is aimed at the treatment of organic matter with high concentration, high toxicity, high color and difficult biodegradation, which can greatly reduce the color and COD of the wastewater and improve the B / C ratio, i.e. the biodegradability of the wastewater.

[0040] The Fenton coagulation pry 6 contains a Fenton coagulation reactor, a lifting pump, a stirrer, a PLC control cabinet and instruments, the instruments include an online pH meter and an online liquid level meter, the reactor is made of carbon steel and internally lined with glass fiber reinforced plastic for corrosion protection, and the hydraulic retention time of each reaction unit is 1 hour.

[0041] After the treatment of the iron-carbon micro-electrolysis reaction pry 6, a large amount of Fe 2+ ions exist in the water, dilute hydrochloric acid is added to adjust the pH of the water to be acidic, and an appropriate amount of H2O2 is added to generate a Fenton reaction. Combined with the iron-carbon micro-electrolysis technology, the Fe 2+ generated by the iron-carbon micro-electrolysis reaction is efficiently utilized to improve the treatment effect and further improve the biodegradability of the wastewater.

[0042] The secondary sludge-water separation pry 7 includes a high-pressure diaphragm plate-and-frame filter press, a squeezing system and a sludge conveying system. The water from the high-pressure diaphragm plate-and-frame filter press is adjusted to neutral and then enters the primary biochemical pry 8.

[0043] The primary biochemical pry 8 includes a primary biochemical conditioning tank, an ABR anaerobic reactor and a contact oxidation tank. The external structure is a carbon steel structure, and the internal structure is glass fiber reinforced plastic for corrosion prevention. The primary biochemical pry 8 also includes a lifting pump, a submersible mixer, a mixed liquid reflux pump, an aeration system and a filler system. The sewage first enters the primary biochemical conditioning tank, is uniformly and quantitatively adjusted, and then is pumped into the ABR anaerobic reactor and then into the contact oxidation tank. The metabolic action of anaerobic microorganisms is used to decompose complex macromolecules and insoluble organic matter into small molecules and soluble organic matter, and finally convert them into methane and carbon dioxide. Then, high-molecular composite fillers are arranged in the aerobic tank to increase the number of microorganisms in the reaction tank, so as to remove most of the COD, ammonia nitrogen and total phosphorus in the wastewater. The pH of the aerobic tank needs to be controlled at 7-8 during the reaction process, so a certain amount of alkali needs to be added. The primary biochemical pry 8 is connected to the primary biochemical fan pry.

[0044] The inclined plate sedimentation pry 9 includes an inclined plate sedimentation tank, a sludge reflux pump and an inclined plate filler. The inclined plate sedimentation tank is used for separating sludge and water. The separated wastewater enters the secondary biochemical pry 10, and a part of the concentrated sludge is refluxed to the contact oxidation tank of the primary biochemical pry 8 to maintain the sludge concentration of the entire biochemical treatment in a relatively stable state.

[0045] The secondary biochemical pry 10 includes a secondary biochemical conditioning tank, an anoxic tank and an MBR tank, and also includes a lifting pump, a mixed liquid reflux pump, an aeration system and an MBR system.

[0046] An anoxic tank is arranged at the front end of the MBR process to perform deep microbial degradation and complete separation of sludge and water mixture. At the same time, two-stage biochemical treatment is realized in the entire biochemical system, and better denitrification and phosphorus removal treatment is performed. The MBR process first removes biodegradable organic pollutants in water by using activated sludge, and then separates the purified water and activated sludge by using a membrane. The MBR process is a new type of sewage treatment process combining high-efficiency membrane separation technology with traditional activated sludge method. The core is to use a membrane assembly to intercept the activated sludge and macromolecular organic matter in the biochemical reaction tank, thereby eliminating the secondary sedimentation tank, increasing the sludge concentration, and enabling the hydraulic retention time (HRT) and the sludge retention time (SRT) to be controlled separately. This process combines the advantages of membrane treatment technology and biological treatment technology, significantly improves the water quality, and the pH of the aerobic tank needs to be controlled at 7-8 during the reaction process, so a certain amount of alkali needs to be added. The secondary biochemical pry is connected to the secondary biochemical fan pry.

[0047] The activated carbon adsorption pry 11 is a carbon steel structure, lined with glass steel for corrosion resistance, containing quartz sand and activated carbon filter material, backwash system, wastewater after activated carbon adsorption pry can be further decolorized, while reducing COD. The activated carbon filter uses activated carbon as the filter medium. Due to its large specific surface area and abundant microporous structure, it can effectively adsorb pollutants in water. Due to the mutual adsorption force between molecules, when a molecule is captured into the activated carbon inner pore by the inner pore of the activated carbon, more molecules will be continuously attracted due to the mutual attraction between molecules until the activated carbon inner pore is filled. Under certain pressure, the MBR effluent passes through a certain thickness of granular or non-granular activated carbon, effectively retaining and removing suspended solids, organic matter, color, odor and part of the heavy metal ions in the water, and finally achieving the effect of reducing water turbidity and purifying water quality. A kind of high-efficiency filtration equipment.

[0048] The water production collection tank 12, the wastewater treated by the activated carbon adsorption pry 11 enters the water production collection tank 12. The water production collection tank 12 is made of PE material, with a volume of 20m 3 . The built-in static pressure liquid level meter.

[0049] The oilfield chemical waste liquid has the characteristics of high COD concentration, poor biodegradability and high suspended solids. The pretreatment is adjusted by the waste liquid adjusting tank 1, then enters the demulsification and coagulation pry 2, adds demulsifier and coagulant for demulsification and coagulation, and then solid-liquid separation is carried out by the first sludge-water separation pry 3. The solid phase is made into mud cake and transported out, and the liquid phase enters the intermediate water tank 4. After adding acid to adjust the pH value in the intermediate water tank 4, it enters the iron-carbon micro-electrolysis reaction pry 5 and the Fenton coagulation pry 6. By using the principle of metal corrosion, iron filings and inert carbon particles form a micro-electrolysis loop in the wastewater, which helps to remove color and odor, improve biodegradability, and add Fenton reagent in the reaction for Fenton reaction. The hydroxyl radicals with strong oxidizing property generated by the reaction can oxidize large molecular organic matter in the wastewater into small molecular state, further improving the biodegradability of the wastewater and improving the subsequent biochemical treatment effect. Then, the secondary sludge-water separation pry 7 is used for separation, and the separated mud phase is made into mud cake and transported out. The liquid phase is subjected to biochemical treatment, and the biochemical section is subjected to the process mode of the first biochemical pry 8, the inclined plate sedimentation pry 9 and the second biochemical pry 10. By suspending the high polymer combined filler in the aerobic tank, the amount of microorganisms is increased, the biochemical treatment efficiency is improved, and the sludge concentration and sludge backflow are carried out by the inclined plate sedimentation tank. An anoxic tank is arranged at the front end of the MBR process section to form two-stage biochemical treatment and improve the system denitrification and nitrogen removal function. Finally, the activated carbon adsorption filter is used, and the effluent enters the water production collection tank 12. The COD, pH, suspended solids and other indicators of the wastewater treated by biochemical and fine filtration can meet the requirements of external drainage.

[0050] The water quality of the oilfield comprehensive waste liquid before and after treatment in the embodiment is shown in Tables 1 and 2.

[0051] Table 1 Influent water quality

[0052]

[0053] Table 2 effluent water quality

[0054]

[0055] Oilfield comprehensive wastewater treatment after the requirements to achieve GB8978-1996 "Integrated Wastewater Discharge Standard" first level standard.

[0056] The above only for the preferred embodiments of the present application, and not to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application, should be included within the scope of the present application.

Claims

1. A system for the treatment of oilfield composite waste fluids, characterized by: The waste liquid adjusting tank (1), the demulsification and coagulation skid (2), the first sludge-water separation skid (3), the intermediate water tank (4), the iron-carbon micro-electrolysis reaction skid (5), the Fenton coagulation skid (6), the second sludge-water separation skid (7), the first biochemical skid (8), the inclined plate sedimentation skid (9), the second biochemical skid (10), the activated carbon adsorption skid (11), and the water production collection tank (12) are sequentially connected. The water outlet of the waste liquid adjusting tank (1) is connected with the water inlet of the demulsification and coagulation skid (2), the water outlet of the demulsification and coagulation skid (2) is connected with the water inlet of the first sludge-water separation skid (3), the water outlet of the first sludge-water separation skid (3) is connected with the water inlet of the intermediate water tank (4), the water outlet of the intermediate water tank (4) is connected with the water inlet of the iron-carbon micro-electrolysis reaction skid (5), the water outlet of the iron-carbon micro-electrolysis reaction skid (5) is connected with the water inlet of the Fenton coagulation skid (6), the water outlet of the Fenton coagulation skid (6) is connected with the water inlet of the second sludge-water separation skid (7), the water outlet of the second sludge-water separation skid (7) is connected with the water inlet of the first biochemical skid (8), the water outlet of the first biochemical skid (8) is connected with the water inlet of the inclined plate sedimentation skid (9), the water outlet of the inclined plate sedimentation skid (9) is connected with the water inlet of the second biochemical skid (10), the water outlet of the second biochemical skid (10) is connected with the water inlet of the activated carbon adsorption skid (11), and the water outlet of the activated carbon adsorption skid (11) is connected with the water inlet of the water production collection tank (12).

2. The treatment system for oilfield integrated waste streams of claim 1, wherein: The water outlet of the water production collection tank (12) is connected with the second biochemical skid (10) and the activated carbon adsorption skid (11) through pipelines.

3. The treatment system for oilfield integrated waste streams of claim 1, wherein: The concentrated sludge separated by the inclined plate sedimentation skid (9) is backflowed to the first biochemical skid (8).

4. The treatment system for oilfield integrated waste streams of claim 1, wherein: The physical and chemical dosing skid is connected with the demulsification and coagulation skid (2), the first sludge-water separation skid (3), the iron-carbon micro-electrolysis reaction skid (5), the Fenton coagulation skid (6), the second sludge-water separation skid (7), the first biochemical skid (8), and the second biochemical skid (10).

5. The treatment system for oilfield integrated waste streams of claim 1, wherein: The first biochemical skid (8) comprises a first biochemical adjusting tank, an ABR anaerobic reactor, and a contact oxidation tank.

6. The treatment system for oilfield integrated waste streams of claim 1, wherein: The second biochemical skid (10) comprises a second biochemical adjusting tank, an anoxic tank, and an MBR tank.

7. The treatment system for oilfield integrated waste streams of claim 1, wherein: The demulsification and coagulation skid (2) comprises a demulsification and coagulation reactor, a lifting pump, a stirrer, a PLC control cabinet, and instruments, and the instruments comprise an online pH meter and an online liquid level meter.

8. The treatment system for oilfield integrated waste streams of claim 1, wherein: The iron-carbon micro-electrolysis reaction skid (5) comprises two iron-carbon reactors and two stirring fans.

9. The treatment system for oilfield integrated waste streams of claim 1, wherein: The Fenton coagulation skid (6) comprises a Fenton coagulation reactor, a lifting pump, a stirrer, a PLC control cabinet, and instruments, and the instruments comprise an online pH meter and an online liquid level meter.

10. The treatment system for oilfield integrated waste streams of claim 1, wherein: The first biochemical skid (8) is connected with a first biochemical fan skid, and the second biochemical skid (10) is connected with a second biochemical fan skid.

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