Process for removing pollutants in oil and gas field wastewater by coupling electron beam irradiation with bentonite

Abstract

The invention discloses a process for removing pollutants in oil and gas field wastewater by coupling electron beam irradiation with bentonite, which comprises the following steps: when the concentration of oil substances in the oil and gas field wastewater is less than or equal to a first concentration, adding quantitative bentonite into the oil and gas field wastewater, and then carrying out electron beam irradiation treatment, after treatment, standing for a period of time, and removing oil substances in the oil and gas field wastewater; and when the concentration of the oil substances is between the first concentration and the second concentration, firstly carrying out electron beam irradiation treatment, then adding bentonite into the treated solution, carrying out electron beam irradiation again, and standing for a period of time after treatment, so that the oil substances in the oil and gas field wastewater are removed. The process is simple to operate, and the oil substances have the advantages of good treatment effect, short treatment time and low treatment cost.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a process for removing pollutants in oil and gas field wastewater by electron beam irradiation coupled with bentonite. Background Art

[0002] The produced water produced during the production process of offshore oil and gas fields contains a lot of oil substances, which will block the spread of oxygen in the air and water environment, causing hypoxia in the water body and affecting the normal metabolic activities of microorganisms in the water body. Therefore, direct discharge of offshore oil and gas field wastewater without treatment will cause serious damage to the marine ecological environment. How to effectively remove oil substances in offshore oil and gas field wastewater is a major difficulty in the field of industrial wastewater treatment.

[0003] Common treatment processes for oil in oil and gas field wastewater include cyclone filtration technology, air flotation technology, fiber coalescence separation technology and membrane separation technology. Cyclone filtration is a technology that combines filtration with centrifugal separation to achieve separation of oil, water and sand. Air flotation is a technology that introduces air into the treated water to produce a large number of tiny bubbles, so that oil substances and bubbles are adsorbed, thereby achieving rapid separation and removal of oil substances. Fiber coalescence separation technology is a technology that coalesces small oil droplets into large oil droplets and then strengthens sedimentation separation. Due to the characteristics of their own processes, these technologies can only remove part of the oil. Membrane separation technology achieves oil-water separation through pore size interception, and the removal effect is better. However, the membrane is prone to clogging, which increases the frequency of membrane backwashing, reduces the service life of the membrane, and increases the treatment cost. How to economically and efficiently treat oil in oil and gas field wastewater is a problem that needs to be solved urgently. Summary of the invention

[0004] In view of the complex water quality of offshore oil and gas field wastewater and the difficulty in removing oil substances, the present invention utilizes electron beam irradiation technology and the interaction between bentonite and oil substances to innovatively propose a process for removing pollutants in oil and gas field wastewater by coupling electron beam irradiation with bentonite.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] A process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite, the process comprising:

[0007] When the concentration of oil substances in oil and gas field wastewater is less than or equal to the first concentration, a quantitative bentonite is added to the oil and gas field wastewater, and then electron beam irradiation treatment is carried out. After standing for a period of time after treatment, the oil substances in the oil and gas field wastewater are removed; when the concentration of oil substances is greater than the first concentration and less than or equal to the second concentration, electron beam irradiation treatment is first carried out, and then bentonite is added to the treated solution, and electron beam irradiation is carried out again. After standing for a period of time after treatment, the oil substances in the oil and gas field wastewater are removed, and the second concentration is greater than the first concentration.

[0008] Optionally, the first concentration is 100 mg / L and the second concentration is 1000 mg / L.

[0009] Optionally, when the concentration of oil substances in oil and gas field wastewater is less than or equal to 100 mg / L, the dosage of bentonite is between 0.5-2 g / L; when the concentration of oil substances in oil and gas field wastewater is greater than 100 mg / L and less than or equal to 1000 mg / L, the dosage of bentonite is between 2-15 g / L.

[0010] Optionally, when the concentration of oil substances in oil and gas field wastewater is less than or equal to 100 mg / L, the electron beam irradiation dose is 1-2 kGy; when the concentration of oil substances in oil and gas field wastewater is greater than 100 mg / L and less than or equal to 1000 mg / L, the electron beam irradiation dose is between 5-30 kGy.

[0011] Optionally, when the concentration of oil substances in oil and gas field wastewater is less than or equal to 100 mg / L, the standing time is 30 minutes; when the concentration of oil substances is greater than 100 mg / L and less than or equal to 1000 mg / L, the standing time is 60 minutes.

[0012] Optionally, the electron beam irradiation is generated by a high energy electron accelerator having an energy between 1-5 MeV.

[0013] Optionally, the energy of the high energy electron accelerator is 2.5 MeV.

[0014] Optionally, the bentonite is sodium bentonite.

[0015] In summary, the technical effects and advantages of the present invention are as follows: the present invention provides a process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite, which makes full use of the interaction between electron beam irradiation, bentonite and oil substances to enhance the removal of oil substances in offshore oil and gas field wastewater. On the one hand, when electron beam irradiation acts on oil substances in offshore oil and gas field wastewater, macromolecular oil substances will be converted into small molecular oil substances. On the other hand, when electron beam irradiation acts on bentonite, copper ions will be released from bentonite, and the hydrogen peroxide produced during the copper ion activation irradiation process will further strengthen the decomposition of small molecular oil substances. At the same time, due to the small interlayer spacing of bentonite, small molecular oil substances are easily fixed in the bentonite structure after entering the bentonite. Through the synergistic effect of the above three processes, the complete removal of oil substances in offshore oil and gas field wastewater can be achieved. The method is simple in process operation, has the advantages of good treatment effect, short treatment time and low treatment cost for oil substances in offshore oil and gas field wastewater, and shows a wide range of application prospects in the field of oil substance treatment in offshore oil and gas field wastewater. DETAILED DESCRIPTION

[0016] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the present invention and its application or use. Based on the embodiments of the present invention, any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts falls within the scope of protection of the present invention. And all other embodiments obtained by ordinary technicians in this field without carrying out creative work are within the scope of protection of the present invention.

[0017] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the prior art in the art can be used. The reagents and other instruments used without indicating the manufacturer are all conventional reagent products that can be obtained commercially. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the specification of the present invention.

[0018] In the description of the present invention, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0019] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] Electron beam irradiation is a new type of chemical oxidation technology. Compared with conventional chemical oxidation technology, electron beam irradiation process has the advantages of strong treatment capacity, high efficiency and no need to add chemical substances. The principle of electron beam irradiation wastewater treatment includes direct action (energy deposition) and indirect action (exciting water molecules to produce active particles). In practical applications, the mechanism of action of electron beam irradiation wastewater treatment is mainly indirect action. Due to the complex water quality of offshore oil and gas field wastewater, the irradiation dose required for electron beam irradiation alone to treat offshore oil and gas field wastewater is relatively high, resulting in a significant increase in treatment costs. Electron beam irradiation technology has been applied to the treatment of actual printing and dyeing wastewater and coking wastewater. Long-term monitoring data show that electron beam irradiation has certain comparative advantages in treatment effect and treatment cost. How to effectively reduce the dose required for electron beam irradiation to treat oil substances in offshore oil and gas field wastewater and improve the treatment effect is the key to whether electron beam irradiation technology can be applied to offshore oil and gas field wastewater.

[0021] Bentonite has unique structural characteristics and good ion exchange properties. my country has abundant bentonite reserves and is cheap. It is a common water treatment agent in the field of industrial wastewater treatment. At present, there are few studies on the use of bentonite to treat oil substances in water. Ren Ruichen et al.'s research shows that calcium-based bentonite can remove oil substances in water, but the amount of calcium-based bentonite is very high (≥20g / L), and the maximum removal rate is less than 80%.

[0022] In response to the above problems, the present invention utilizes the interaction among electron beam irradiation, bentonite and oil substances to enhance the removal of oil substances in offshore oil and gas field wastewater, thereby achieving the goal of reducing the electron beam irradiation dose and the amount of bentonite added while improving the effective removal of oil substances in offshore oil and gas field wastewater.

[0023] The present application proposes a process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite, the process comprising:

[0024] When the concentration of oil in the oil and gas field wastewater is less than or equal to the first concentration, a certain amount of bentonite is added to the oil and gas field wastewater, and then electron beam irradiation treatment is performed. After standing for a period of time after treatment, the oil in the oil and gas field wastewater is removed; when the concentration of oil is greater than the first concentration and less than or equal to the second concentration, electron beam irradiation treatment is first performed, and then bentonite is added to the treated solution, and electron beam irradiation is performed again. After standing for a period of time after treatment, the oil in the oil and gas field wastewater is removed, and the first concentration is less than the second concentration. Among them, the first concentration is 100 mg / L and the second concentration is 1000 mg / L.

[0025] The dosage of bentonite is related to the content of oil in offshore oil and gas field wastewater. When the concentration of oil in oil and gas field wastewater is less than or equal to 100 mg / L, the dosage of bentonite is between 0.5-2 g / L; when the concentration of oil in oil and gas field wastewater is greater than 100 mg / L and less than or equal to 1000 mg / L, the dosage of bentonite is between 2-15 g / L.

[0026] Optionally, the electron beam irradiation dose is related to the content of oil substances in offshore oil and gas field wastewater. When the concentration of oil substances in oil and gas field wastewater is less than or equal to 100 mg / L, the electron beam irradiation dose is 1-2 kGy; when the concentration of oil substances in oil and gas field wastewater is greater than 100 mg / L and less than or equal to 1000 mg / L, the electron beam irradiation dose is between 5-30 kGy.

[0027] Optionally, when the concentration of oil substances in oil and gas field wastewater is less than or equal to 100 mg / L, the standing time is 30 minutes; when the concentration of oil substances is greater than 100 mg / L and less than or equal to 1000 mg / L, the standing time is 60 minutes.

[0028] Optionally, the electron beam irradiation is generated by a high energy electron accelerator having an energy between 1-5 MeV.

[0029] Optionally, the energy of the high energy electron accelerator is 2.5 MeV.

[0030] Optionally, the bentonite is sodium bentonite, which is a commercially available product.

[0031] In summary, the present application provides a process for removing pollutants from oil and gas field wastewater by coupling electron beam irradiation with bentonite, which makes full use of the interaction between electron beam irradiation, bentonite and oil substances to enhance the removal of oil substances in offshore oil and gas field wastewater. On the one hand, when electron beam irradiation acts on oil substances in offshore oil and gas field wastewater, macromolecular oil substances will be converted into small molecule oil substances. On the other hand, when electron beam irradiation acts on bentonite, copper ions will be released from bentonite, and the hydrogen peroxide produced during the copper ion activation irradiation process will further strengthen the decomposition of small molecule oil substances. At the same time, due to the small interlayer spacing of bentonite, small molecule oil substances are easily fixed in the bentonite structure after entering the bentonite. Through the synergistic effect of the above three processes, the complete removal of oil substances in offshore oil and gas field wastewater can be achieved. The method is simple in process operation, has the advantages of good treatment effect, short treatment time and low treatment cost for oil substances in offshore oil and gas field wastewater, and has shown a wide range of application prospects in the field of oil substance treatment in offshore oil and gas field wastewater.

[0032] Example 1

[0033] The COD of wastewater from an oil and gas field in a certain place is 1510mg / L, the concentration of oil substances is 97mg / L, and the pH of the wastewater is 7.1. Electron beam irradiation coupled with bentonite is used to treat the prepared wastewater. The bentonite dosage is 1.5g / L, the irradiation dose is 1.5kGy, and after standing for 30 minutes after irradiation treatment, the concentration of oil substances in the produced water is measured to be 3.8mg / L.

[0034] Example 2

[0035] The COD (chemical oxygen demand) of the wastewater from an oil and gas field in a certain place is 1935mg / L, the concentration of oil substances is 82mg / L, and the pH of the wastewater is 7.2. Electron beam irradiation coupled with bentonite is used to treat the prepared wastewater. The bentonite dosage is 2g / L, the irradiation dose is 1.5kGy, and after standing for 30 minutes after irradiation treatment, it is measured that the oil substances in the produced water are completely removed.

[0036] Example 3

[0037] The COD of the wastewater from an oil and gas field in a certain place is 1735mg / L, the concentration of oil substances is 317mg / L, and the pH of the wastewater is 7.2. The prepared wastewater is treated by electron beam irradiation coupled with bentonite. First, the prepared wastewater is treated by electron beam irradiation with an irradiation dose of 5kGy. After irradiation, 5g / L bentonite is added, and then the electron beam irradiation is used again with an irradiation dose of 10kGy. After standing for 60min after treatment, the concentration of oil substances in the wastewater is measured to be 47mg / L. When the bentonite dosage is 10g / L, the second irradiation dose is 15kGy, and after standing for 60min after treatment, it is measured that the oil substances in the wastewater are completely removed.

[0038] Example 4

[0039] The COD of the wastewater from an oil and gas field in a certain place is 11265mg / L, the concentration of oil substances is 914mg / L, and the pH of the wastewater is 7.4. Electron beam irradiation coupled with bentonite is used to treat the prepared wastewater. First, the prepared wastewater is treated with electron beam irradiation, with an irradiation dose of 10kGy. After irradiation treatment, 10g / L bentonite is added, and then electron beam irradiation is used again, with an irradiation dose of 10kGy. After standing for 60min after treatment, the concentration of oil substances in the wastewater is measured to be 272mg / L. When the bentonite dosage is 15g / L, the second irradiation dose is 20kGy, and after standing for 60min after treatment, it is measured that the oil substances in the wastewater are completely removed.

[0040] Example 5

[0041] As shown in Table 1, the COD of wastewater from an oil and gas field in a certain place is 1935 mg / L, the concentration of oil substances is 82 mg / L, and the pH of the wastewater is 7.2. Electron beam irradiation coupled with bentonite is used to treat the produced water. When the bentonite dosage is 1 g / L and the irradiation dose is 1 kGy, the concentration of copper ions dissolved in the water is 7.7 mg / L. When the bentonite dosage is 1.5 g / L, the concentration of copper ions dissolved in the water is 9.4 mg / L. When the bentonite dosage is 2 g / L, the concentration of copper ions dissolved in the water is 15.3 mg / L, which proves that electron beam irradiation technology can dissolve copper ions in bentonite. This part of copper ions will promote the activation and decomposition of hydrogen peroxide formed in situ during the electron beam irradiation process, increase the concentration of oxidative active species in the system, and thus enhance the removal of oil substances in the produced water.

[0042] Table 1 Concentration of copper ions dissolved from PFS during electron beam irradiation under different conditions

[0043]

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0045] For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily required by the present invention.

[0046] The above is a detailed introduction to a method for effectively removing oil substances from offshore oil and gas field wastewater provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite, characterized in that: The process comprises: When the concentration of oil substances in oil and gas field wastewater is less than or equal to the first concentration, a quantitative bentonite is added to the oil and gas field wastewater, and then electron beam irradiation treatment is carried out. After standing for a period of time after treatment, the oil substances in the oil and gas field wastewater are removed; when the concentration of oil substances is greater than the first concentration and less than or equal to the second concentration, electron beam irradiation treatment is first carried out, and then bentonite is added to the treated solution, and electron beam irradiation is carried out again. After standing for a period of time after treatment, the oil substances in the oil and gas field wastewater are removed, and the second concentration is greater than the first concentration.

2. The process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite according to claim 1 is characterized in that: The first concentration is 100 mg / L, and the second concentration is 1000 mg / L.

3. The process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite according to claim 2 is characterized in that: When the concentration of oil in oil and gas field wastewater is less than or equal to 100 mg / L, the dosage of bentonite is between 0.5-2 g / L; when the concentration of oil in oil and gas field wastewater is greater than 100 mg / L and less than or equal to 1000 mg / L, the dosage of bentonite is between 2-15 g / L.

4. The process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite according to claim 2 is characterized in that: When the concentration of oil in oil and gas field wastewater is less than or equal to 100 mg / L, the electron beam irradiation dose is 1-2 kGy; when the concentration of oil in oil and gas field wastewater is greater than 100 mg / L and less than or equal to 1000 mg / L, the electron beam irradiation dose is between 5-30 kGy.

5. The process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite according to claim 2 is characterized in that: When the concentration of oil substances in oil and gas field wastewater is less than or equal to 100 mg / L, the standing time is 30 minutes; when the concentration of oil substances is greater than 100 mg / L and less than or equal to 1000 mg / L, the standing time is 60 minutes.

6. The process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite according to claim 1 is characterized in that: Electron beam irradiation is produced by a high-energy electron accelerator with an energy ranging from 1-5 MeV.

7. The process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite according to claim 6 is characterized in that: The energy of the high-energy electron accelerator is 2.5 MeV.

8. The process for removing pollutants from oil and gas field wastewater by electron beam irradiation coupled with bentonite according to claim 1, characterized in that: The bentonite is sodium bentonite.

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