CN115215413A - Pretreatment method for polymer-containing wastewater - Google Patents

Pretreatment method for polymer-containing wastewater Download PDF

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Publication number
CN115215413A
CN115215413A CN202210645838.0A CN202210645838A CN115215413A CN 115215413 A CN115215413 A CN 115215413A CN 202210645838 A CN202210645838 A CN 202210645838A CN 115215413 A CN115215413 A CN 115215413A
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Prior art keywords
polymer
containing wastewater
electrochemical device
electrochemical
water
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CN202210645838.0A
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Chinese (zh)
Inventor
雷太平
谢陈鑫
钱光磊
张程蕾
赵慧
任春燕
李旗
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Tianjin Zhengda Science & Technology Co ltd
CNOOC Tianjin Chemical Research and Design Institute Co Ltd
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Tianjin Zhengda Science & Technology Co ltd
CNOOC Tianjin Chemical Research and Design Institute Co Ltd
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Priority to CN202210645838.0A priority Critical patent/CN115215413A/en
Publication of CN115215413A publication Critical patent/CN115215413A/en
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/46Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/24Treatment of water, waste water, or sewage by flotation
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/30Organic compounds
    • C02F2101/32Hydrocarbons, e.g. oil
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/30Organic compounds
    • C02F2101/38Organic compounds containing nitrogen
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00Controlling or monitoring parameters in water treatment
    • C02F2209/08Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00Controlling or monitoring parameters in water treatment
    • C02F2209/10Solids, e.g. total solids [TS], total suspended solids [TSS] or volatile solids [VS]

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Water Supply & Treatment (AREA)
  • Environmental & Geological Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Health & Medical Sciences (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

The invention discloses a pretreatment method of polymer-containing wastewater, which comprises the following steps: introducing the polymer-containing wastewater into an electrochemical device for electrochemical reaction, and carrying out water-sewage separation on the polymer-containing wastewater treated by the electrochemical device through an air flotation process. By adopting the combined method of electrochemical coagulation breaking and air flotation, the invention realizes effective destruction to the polymer, reduces the treatment difficulty caused by the influence of the polymer, realizes effective removal to the oil content and suspended matters, and can partially remove COD. According to the actual use requirement, the method can be used for reinjection after treatment or as a pre-pretreatment process of standard treatment, solves the problems of high polymer content, high viscosity, high oil-water separation difficulty and the like of the polymer-containing wastewater, and provides a method for quickly and effectively breaking a chain, removing oil and removing suspended matters.

Description

Pretreatment method for polymer-containing wastewater
Technical Field
The invention relates to a wastewater pretreatment method, in particular to a pretreatment method of polymer-containing wastewater generated in the process of oilfield exploitation.
Background
With the increase of the difficulty of crude oil extraction, new oil extraction technologies are widely used in various oil fields. Wherein the polymer flooding technology is a commonly used and effective oil production technology. With the use of polymer flooding technology, environmental problems also come along, for example, the produced water of an oil field contains a large amount of polymers such as polyacrylamide, an active agent and the like, and the viscosity of the waste water is high, so that the difficulty of oil-water separation is high, and the difficulty of waste water treatment is correspondingly increased.
At present, the treatment of polymer-containing wastewater usually adopts physical, pyrolysis, biodegradation, chemical oxidation, ultrasonic treatment and other treatment methods, and the oil-water separation difficulty is high due to the characteristics of high polymer content, high viscosity and the like of the polymer-containing wastewater, so that the methods have the problems of unsatisfactory treatment effect, high energy consumption, poor biological tolerance, long treatment time, difficult control of reaction conditions and the like in the treatment process, thereby restricting the rapid and effective treatment of the polymer-containing wastewater.
Disclosure of Invention
In order to overcome the defects of non-ideal treatment effect, long treatment time, difficult control of conditions and the like in the prior art, the invention provides the pretreatment method of the polymer-containing wastewater, which can realize the polymerization breaking effect on the polymer-containing wastewater quickly, stably and efficiently and realize the effective separation of oil, water and slag water, thereby laying a good foundation for reinjection application or standard treatment.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a method for pretreating polymer-containing wastewater, comprising the following steps:
1) Introducing the polymer-containing wastewater into an electrochemical device for electrochemical reaction;
2) Carrying out water and sewage separation on the polymer-containing wastewater treated by the electrochemical device through an air floatation process;
the electrochemical device is an electrochemical reactor which is formed by fixing cathodes and anodes in a reaction device in an alternating arrangement mode and arranging adjacent cathode and anode polar plates at a distance of 3-15 mm;
the air floatation process is a dissolved air floatation process and is used for oil-water separation and residue-water separation.
In the method, the anode of the electrochemical device adopts a titanium-based coating electrode, and the coating is iridium, tin or lead and oxides thereof; the cathode adopts the same type of anode electrode or graphite electrode or stainless steel electrode.
In the method of the present invention, it is preferable that the current density during the operation of the electrochemical device is 100 to 300A/m 2 And the polymer-containing wastewater stays in the electrochemical device for 3-20min during working.
Further preferably, the dissolved air pressure of the air floatation process is controlled to be 0.2-0.3MPa, the rising speed of the water flow in the contact area is 10-20mm/s, the retention time of the contact area is 60-90s, the rising speed of the water flow in the separation area is 1-3mm/s, and the retention time of the separation area is 5-10min.
The polymer-containing wastewater has the oil content of 50-250mg/L, the suspended matter content of 50-350mg/L and the COD content of 1000-3500mg/L.
The invention utilizes the electric field action of the electrochemical device and strong oxidizing groups generated in the electrochemical process to carry out chain scission and polymerization breaking on the polymer-containing wastewater, destroys the stable state of the polymer-containing wastewater and lays a good foundation for realizing effective water and sewage separation of the polymer-containing wastewater. The wastewater after electrochemical treatment can be effectively subjected to oil-water separation and residue-water separation by an air floatation process. The pretreatment method of the polymer-containing wastewater can be used for reinjection after treatment or as a pretreatment process for standard discharge.
The invention has the beneficial effects that:
1. the breaking and gathering efficiency is high. The invention adopts an electrochemical pretreatment method, realizes the chain breaking effect on the polymer in the wastewater under the combined action of an electric field and a strong oxidizing group, destroys the stability of the water body and lays a good foundation for the subsequent treatment means.
2. The treatment process is short. The invention adopts the flow of electrochemical reaction and air flotation separation to realize effective damage to the medium polymer in the wastewater, ensures that the air flotation process can effectively realize effective removal of oil content and suspended matters, and has the characteristic of short treatment flow.
3. The pretreatment effect is good. By adopting the method to treat polymer-containing wastewater, the effluent oil content and the suspended solid content (SS) can meet the relevant requirements of 'water injection quality recommendation index of clastic rock oil reservoir and analysis method SY/T5329-94' in the middle oil industry standard. Meanwhile, partial COD can be removed, and if the wastewater meets the discharge standard, the polymer-containing wastewater treated by the method can well meet the water inlet requirement of the conventional wastewater treatment system, and the treatment pressure of the system is reduced.
The electrochemical treatment method is developed in a targeted manner aiming at the characteristics of polymer-containing wastewater, the polymer in the wastewater can be effectively damaged by adjusting electrochemical operation parameters, the viscosity and the stability of a water body are reduced, the water-sewage separation is effectively realized, and the purpose of primarily purifying water quality is achieved or the electrochemical treatment method is used as a pretreatment method for standard treatment.
Drawings
Figure 1 is a schematic view of the principle and arrangement of an electrochemical device according to the present invention,
in the figure: 1 an electrochemical device housing; 2 an anode; 3, a cathode; 4 an anode electrode connector; 5 a cathode electrode connector; 6 connecting the anode of the power supply externally; 7 connecting the cathode of the power supply; 8, a water inlet; 9 water outlet; a represents a plate pitch
Detailed Description
The technical solutions and advantages of the present invention will be further described with reference to the following embodiments and accompanying drawings.
Example 1:
the initial water quality of certain polymer-containing wastewater in the Suizhong oil field is shown in Table 1.
TABLE 1
Item Oil content mg/L SSmg/L CODmg/L
Quality of raw water 153.6 284.3 2790
As shown in fig. 1, the electrochemical device includes an electrochemical device housing 1; the electrochemical device shell 1 is provided with a water inlet 8 and a water outlet 9 of the device, an anode group formed by connecting 5 anodes 2 through an anode electrode connector 4 and a cathode group formed by connecting a cathode 3 through a cathode electrode connector 5 are arranged in the device, wherein the cathodes and the anodes are fixed in the reaction device in an alternative arrangement mode, and the distance between adjacent cathode and anode polar plates is 3-15 mm; the anode group is provided with an external power supply anode 6; the cathode group is provided with an external power supply cathode 7. The anode of the electrochemical device adopts a titanium-based stannic oxide coating electrode, and the cathode adopts a stainless steel electrode. The structural form of the electrochemical device based on the principle can be set to be rectangular or circular, and the arrangement mode can adopt a vertical mode or a horizontal mode.
Introducing polymer-containing wastewater into an electrochemical device, setting the distance between polar plates to be 6mm and the current density to be 120A/m 2 The electrochemical reaction time is 12min, the effluent of the electrochemical device adopts air flotation separation, the dissolved air pressure is 0.3MPa, the rising speed of the water flow in the contact area is 15mm/s, the retention time of the contact area is 80s, the rising speed of the water flow in the separation area is 2mm/s, and the retention time of the separation area is 8min.
After the treatment by the method, the removal rate of the oil content reaches 93 percent, the removal rate of SS reaches 96.9 percent, and the removal rate of COD is 23.1 percent. The effluent quality analysis is shown in table 2.
TABLE 2
Item Oil content mg/L SSmg/L CODmg/L
Water outlet result 10.7 8.8 2145
Removal rate 93.0% 96.9% 23.1%
Example 2:
the polymer-containing wastewater in the Xinjiang oil field has high viscosity of the suspension and very stable system. The initial water quality is shown in Table 3.
TABLE 3
Item Oil content mg/L SSmg/L CODmg/L
Results from raw water 205.8 345.6 3145
The anode of the electrochemical device adopts a titanium-based lead dioxide coating electrode, and the cathode adopts a graphite electrode.
Introducing polymer-containing wastewater into an electrochemical device, wherein the distance between polar plates is 6mm, and the current density is set to be 160A/m 2 The electrochemical reaction time is 16min, the water discharged from the electrochemical device is separated by air flotation, the dissolved air pressure is 0.3MPa, the rising speed of the water flow in the contact area is 10mm/s, the retention time of the contact area is 90s, the rising speed of the water flow in the separation area is 1mm/s, and the retention time of the separation area is 10min.
After the treatment by the method, the removal rate of the oil content reaches 93.3 percent, the removal rate of SS reaches 94.4 percent, and the removal rate of COD is 22.1 percent. The effluent quality analysis is shown in table 4.
TABLE 4
Item Oil content mg/L SSmg/L CODmg/L
Water outlet result 13.8 19.3 2450
Removal rate 93.3% 94.4% 22.1%
Example 3:
the initial water quality of a certain polymer-containing wastewater in Daqing oil field is shown in Table 5.
TABLE 5
Item Oil content mg/L SSmg/L CODmg/L
Results from raw water 95.2 188.4 1850
The anode of the electrochemical device adopts a titanium-based iridium oxide coating electrode, and the cathode adopts the same electrode as the anode.
Introducing polymer-containing wastewater into an electrochemical device, wherein the distance between polar plates is 6mm, and the current density is set to be 300A/m 2 The electrochemical reaction time is 3min, the effluent of the electrochemical device adopts air flotation separation, the effluent of the electrochemical device carries out air flotation separation, and the pressure of dissolved air is0.2MPa, the rising speed of the water flow in the contact zone is 20mm/s, the retention time of the contact zone is 60s, the rising speed of the water flow in the separation zone is 3mm/s, and the retention time of the separation zone is 5min.
After the treatment by the method, the removal rate of oil content reaches 94.3%, the removal rate of SS reaches 97%, and the removal rate of COD is 26.8%. The effluent quality analysis is shown in table 6.
TABLE 6
Item Oil content mg/L SSmg/L CODmg/L
Water outlet result 5.4 5.6 1355
Removal rate of 94.3% 97.0% 26.8%
The above embodiments are specific examples in the practical process, and do not limit the technical scope of the present invention, so any minor modifications, structural modifications or arrangement modifications, etc. made to the method of the present invention still belong to the technical scope of the present invention.

Claims (5)

1. The pretreatment method of the polymer-containing wastewater is characterized by comprising the following steps:
1) Introducing the polymer-containing wastewater into an electrochemical device for electrochemical reaction;
2) The polymer-containing wastewater treated by the electrochemical device is subjected to water and sewage separation by an air flotation process.
The cathode and the anode of the electrochemical device are fixed in the reaction device in an alternating arrangement mode, and the adjacent cathode and anode polar plates are arranged in a mode of 3-15mm in distance to form the electrochemical reactor;
the air floatation process is a dissolved air floatation process and is used for oil-water separation and residue-water separation.
2. The method of claim 1, wherein the pretreatment of the polymer-containing wastewater comprises: the anode of the electrochemical device adopts a titanium-based coating electrode, and the coating is iridium, tin or lead and oxides thereof; the cathode adopts the same type of electrode as the anode or a graphite electrode or a stainless steel electrode.
3. The method for pretreating polymer-containing wastewater according to claim 1, wherein: the current density of the electrochemical device in the working process is 100-300A/m 2 And the polymer-containing wastewater stays in the electrochemical device for 3-20min during working.
4. The method of claim 1, wherein the pretreatment of the polymer-containing wastewater comprises: the air floatation process controls the dissolved air pressure to be 0.2-0.3MPa, the rising speed of water flow in a contact area to be 10-20mm/s, the retention time of the contact area to be 60-90s, the rising speed of the water flow in a separation area to be 1-3mm/s, and the retention time of the separation area to be 5-10min.
5. The method for pretreating polymer-containing wastewater according to claim 1, wherein: the polymer-containing wastewater has oil content of 50-250mg/L, suspended matter content of 50-350mg/L and COD content of 1000-3500mg/L.
CN202210645838.0A 2022-06-12 2022-06-12 Pretreatment method for polymer-containing wastewater Pending CN115215413A (en)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101050040A (en) * 2007-05-14 2007-10-10 北京科技大学 Apparatus for treating sewage containing oil, and processing technique
CN101602531A (en) * 2009-07-16 2009-12-16 华南理工大学 A kind of electrochemical method of oil removal of wastewater produced in oil extraction by polymer flooding displacement
CN102336491A (en) * 2010-07-14 2012-02-01 北京纬纶华业环保科技股份有限公司 Advanced treatment and recycling method for polymer-bearing oil extraction waste water
WO2017067161A1 (en) * 2015-10-20 2017-04-27 波鹰(厦门)科技有限公司 Treatment device and method for oil extraction wastewater
CN107226578A (en) * 2016-03-24 2017-10-03 长江三星能源科技股份有限公司 One kind is used for offshore oilfield polymer-bearing waste-water reinjection treatment method
CN111072190A (en) * 2020-01-03 2020-04-28 浙江钰烯腐蚀控制股份有限公司 Electrocatalytic oxidation and air flotation coalescence treatment process method and equipment for oil-containing sewage
CN111196652A (en) * 2019-09-19 2020-05-26 河南中原石油助剂有限公司 Oil control and mud reduction treatment method and system for oilfield produced water

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101050040A (en) * 2007-05-14 2007-10-10 北京科技大学 Apparatus for treating sewage containing oil, and processing technique
CN101602531A (en) * 2009-07-16 2009-12-16 华南理工大学 A kind of electrochemical method of oil removal of wastewater produced in oil extraction by polymer flooding displacement
CN102336491A (en) * 2010-07-14 2012-02-01 北京纬纶华业环保科技股份有限公司 Advanced treatment and recycling method for polymer-bearing oil extraction waste water
WO2017067161A1 (en) * 2015-10-20 2017-04-27 波鹰(厦门)科技有限公司 Treatment device and method for oil extraction wastewater
CN107226578A (en) * 2016-03-24 2017-10-03 长江三星能源科技股份有限公司 One kind is used for offshore oilfield polymer-bearing waste-water reinjection treatment method
CN111196652A (en) * 2019-09-19 2020-05-26 河南中原石油助剂有限公司 Oil control and mud reduction treatment method and system for oilfield produced water
CN111072190A (en) * 2020-01-03 2020-04-28 浙江钰烯腐蚀控制股份有限公司 Electrocatalytic oxidation and air flotation coalescence treatment process method and equipment for oil-containing sewage

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
郭书海: "《污染土壤电动修复原理与技术》", 中国环境出版社, pages: 69 *

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