CN102974600A - Periodic-dosing oil-gas-liquid three-phase extraction device and method thereof for repairing petroleum-contaminated soil - Google Patents

Abstract

The invention discloses a periodic dosing oil-gas-liquid three-phase extraction device and a method for repairing oil-polluted soil, which belong to the technical field of in-situ restoration of oil-polluted environments. The operation of the periodic dosing system in this device is to use an air compressor to perform pneumatic shock cracking around the gas cracking/dosing well for 3 hours under the condition of a pressure of 0.2-0.7 MPa to increase the porosity of the surrounding soil, and then inject nutrients And surfactant drugs are periodically injected into the injection well to promote the growth of local microorganisms in the soil, promote the dispersion and solubilization of pollutants on soil particles, and facilitate the degradation of petroleum pollutants. The device and method of the present invention make full and effective use of the added drugs, save the cost of drugs, and periodically add drugs to facilitate the full interaction between the drugs and petroleum hydrocarbon pollutants, improve the efficiency of the repair system, and increase the total volume of petroleum pollutants in the soil. Up to 20%-40%, the suction rate increased by 50%-65%.

Description

Periodically dosing oil-gas-liquid three-phase extraction device and method for repairing oil-contaminated soil

technical field

The invention belongs to the technical field of in-situ remediation of petroleum-polluted environments, and in particular relates to a periodic dosing oil-gas-liquid three-phase extraction device and a method for remediating petroleum-contaminated soil.

Background technique

In the past few decades, restricted by various factors such as economic and technological conditions in the historical period and people's awareness level, while petroleum companies have made great contributions to the country, they have also brought a series of environmental problems: Waste water in the process of oil and gas extraction The discharge of pollutants such as waste gas, ground crude oil, and waste gas drilling fluid into the environment will affect the water body, atmosphere, soil and ecological environment. With the wide application of petroleum resources, petroleum pollution in the environment is becoming more and more serious. During the process of oil production, storage, transportation, refining, processing, and use, there will also be spillage and discharge of petroleum hydrocarbons, causing serious oil pollution to the water and soil around oil fields and petrochemical plants. The total oil production in the world today is about 2.2 billion tons per year, of which 1.75 billion tons are produced by land oil fields. In the world, 8 million tons enter the environment every year, and in China, nearly 600,000 tons enter the environment every year, polluting soil, groundwater, rivers and oceans, and adding 1x10 ⁵ tons of polluted soil every year.

Since the 1980s, soil oil pollution has become an environmental issue of widespread concern around the world. The restoration methods that emerged at the historic moment mainly include physical methods, chemical methods and biological methods. Generally speaking, the early methods of treating oil-contaminated soil are mainly traditional physical (steam method, air pumping method, organic solvent method, hydraulic flushing method) and chemical methods (oxidation method, heat treatment method). The effect is quick, but there are disadvantages such as secondary pollution and high treatment costs, which are not conducive to wide application. Bioremediation is a new technology that uses artificial biology to intervene in the purification ability of soil ecosystem with the in-depth research on the dynamic purification ability of soil ecosystem itself, especially the addition of biosurfactant or biosurfactant-producing bacteria can The repair time is greatly shortened, the repair efficiency is improved, and good environmental friendliness can be maintained. It has the advantages of complete degradation of pollutants, no secondary pollution, simple operation and low overall cost, applicable to different types of (in-situ/ex-situ) restoration methods, and the ability to restore the ecosystem and beautify the environment at the same time. And become the latest and fastest-growing governance technology. So far, the improvement of oil-contaminated soil through bioremediation technology is considered to be the most vital and representative technology. As an environmentally friendly technology, it has become a hot spot in international scientific research.

According to the analysis, the so-called bioremediation of contaminated soil refers to the use of plants, microorganisms and other organisms to remove or degrade the pollutants existing in the soil into harmless substances, so that the concentration of pollutants in the soil can be reduced to an acceptable level. Developed countries attach great importance to bioremediation technology, and have invested a lot of money in the research and application of soil pollution restoration. A large number of research institutions and commercial companies are engaged in the research of this technology. Germany invested about 6 billion US dollars in soil purification in 1995, and the United States invested more than 10 billion US dollars in soil remediation in the 1990s. Their research has proved that bioremediation technology that uses biological decomposition of toxic and harmful substances is an effective way to treat large-scale polluted areas. a valuable method.

In soil remediation, water solubility is an important factor affecting the removal of pollutants. Many pollutants are highly hydrophobic substances. The general water washing repair speed is slow and the efficiency is low. In recent years, people have added various additives to enhance repair. As a result, these additives can promote the dispersion and solubilization of pollutants on soil particles, thereby achieving the effect of shortening the time and improving the removal rate of pollutants.

Contents of the invention

The purpose of the present invention is to provide a periodic dosing oil-gas-liquid three-phase extraction device.

The purpose of the present invention is also to provide a method for remediating oil-contaminated soil based on a three-phase oil-gas-liquid extraction device with periodic dosing.

A periodic dosing oil-gas-liquid three-phase extraction device, which is composed of a periodic dosing system and an oil-gas-liquid three-phase extraction system. In the periodic dosing system, the air compressor 1 and the periodic dosing device 2 are respectively It is connected with the control system 3, the air compressor 1 is connected with the gas cracking pipe 4, the periodic dosing device 2 is connected with the dosing pipe 5, and the gas splitting pipe 4 and the dosing pipe 5 are respectively connected with the gas cracking/dosing well 6; In the oil-gas-liquid three-phase extraction system, the suction pump 7 is connected to the gas-liquid separation device 8 and the suction pipe 18 respectively, and the gas-liquid separation device 8 is connected to the liquid ring pump 9 and the delivery pump 12 respectively, and the liquid ring pump 9, gas treatment The device 10 and the gas recovery device 11 are connected in sequence, the delivery pump 12 is connected with the water-oil separation device 13, the water-oil separation device 13 is connected with the oil phase recovery device 14 and the water phase treatment device 15 respectively, and the water phase treatment device 15 is connected with the water phase return The irrigation device 16 is connected, and the suction pipe 18 is connected with the suction well 17 .

The method for remediating oil-contaminated soil based on the above-mentioned periodical dosing oil-gas-liquid three-phase extraction device comprises the following steps:

1) Use the air compressor 1 to perform pneumatic shock cracking around the gas cracking/dosing well 6 for 3 hours at a pressure of 0.2-0.7 MPa;

2) Turn on the periodic dosing device 2 to inject nutrients and surfactants into the gas cracking/dosing well 6, dosing for 9 hours, and then stop gas cracking and dosing for 12 hours, this operation is a cycle;

3) At the same time as dosing, start the suction pump 7 to pump the petroleum pollutants to the ground surface through the suction pipe 18 in the suction well 17, and then enter the gas-liquid separation device 8; the separated gas phase is passed into the gas processing device 10 for treatment. After passing through the gas recovery device 11 or discharge; the separated liquid phase is passed into the water-oil separation device 13 to be separated into an oil phase and a water phase, the oil phase is passed into the oil phase recovery device 14 for processing, and the water phase is passed into the water phase processing device 15 for processing and then enters the water phase Recharging device 16;

4) When the oil-gas-liquid three-phase extraction system is turned on, repeat steps 1) and 2) for periodic dosing, and monitor the pH, COD, and petroleum hydrocarbon content of the suction well exudate in real time. When the pH value is 6- 9. Stop dosing when the COD is less than 100mg/L and the petroleum hydrocarbon content is less than 10mg/L.

Step 2) The nutritional elements are composed of nitrogen, phosphorus and trace elements, wherein the addition intensity of nitrogen and phosphorus is: the weight ratio of the carbon content of pollutants in the soil to nitrogen and phosphorus elements C:N:P is 100 : (4-7): (0.8-1.3); the trace elements in the nutrients are magnesium, iron, calcium, copper, cobalt, manganese, zinc, boron, molybdenum and selenium, and the weight ratio of the trace elements of carbon is 1: ( ^{10-8-10-3 )} .

The surfactant described in step 2) is a conventional surfactant, and its mass is 0.005-0.02 of the total mass of petroleum pollutants in the soil.

The beneficial effects of the present invention are: 1) Periodic dosing during the suction process greatly improves the degradability of petroleum pollutants and heavy metals in the soil; 2) The suction and separation of the water-oil mixture are integrated, and the equipment Compact structure, simple operation and high reliability; 3) The removal rate of petroleum hydrocarbon organic pollutants is above 95%, and the one-time repair effect is good; 4) The repair cycle is short, the repair time is reduced by 10%-25%, and no secondary secondary pollution; 5) The total suction volume of the post-treatment system after adding NLBS is increased by 20%-40%, and the suction rate is increased by 50%-65%; The oil pollution caused by the production of , chemical products, etc. has a good treatment effect, and the invention has broad market prospects.

Description of drawings

Figure 1 is a schematic diagram of a periodic dosing oil-gas-liquid three-phase extraction device;

In the figure, 1-air compressor, 2-periodically dosing device, 3-control system, 4-gas cracking tube, 5-dosing tube, 6-gas cracking/dosing well, 7-suction pump, 8 -Gas-liquid separation device, 9-liquid ring pump, 10-gas treatment device, 11-gas recovery, 12-transport pump, 13-water oil separation device, 14-oil phase recovery device, 15-water phase treatment device, 16 -Aqueous phase recharge device, 17-suction well, 18-suction pipe.

Fig. 2 Comparison results of the total suction volume of the extraction system after no drug addition and periodic drug addition.

Fig. 3 The comparison results of the suction rate of the extraction system after no dosing and periodic dosing.

Detailed ways

Below in conjunction with accompanying drawing and specific example the present invention will be further described:

The periodic dosing oil-gas-liquid three-phase extraction device shown in Figure 1 is composed of a periodic dosing system and an oil-gas-liquid three-phase extraction system. In the periodic dosing system, the air compressor 1 and the periodic dosing system The medicine device 2 is connected with the control system 3 respectively, the air compressor 1 is connected with the air cracking pipe 4, the periodic dosing device 2 is connected with the medicine feeding pipe 5, and the air splitting pipe 4 and the medicine feeding pipe 5 are respectively connected with the gas cracking/dosing pipe The well 6 is connected; the suction pump 7 in the oil-gas-liquid three-phase extraction system is connected with the gas-liquid separation device 8 and the suction pipe 18 respectively, and the gas-liquid separation device 8 is connected with the liquid ring pump 9 and the delivery pump 12 respectively, and the liquid ring pump 9. The gas treatment device 10 and the gas recovery device 11 are connected in sequence, the delivery pump 12 is connected with the water-oil separation device 13, the water-oil separation device 13 is connected with the oil phase recovery device 14 and the water phase treatment device 15 respectively, and the water phase treatment device 15 It is connected with the water phase refilling device 16 , and the suction pipe 18 is connected with the suction well 17 .

Figure 2 and Figure 3 respectively reflect the comparison of the total suction volume and suction rate of the extraction system before and after adding the periodic dosing system in the pilot test. It can be seen that the removal rate and The suction efficiency is significantly improved, in which the total suction volume can be increased by 20% - 40%, and the suction rate can be increased by 50% - 65%.

In 2010, a set of the above-mentioned periodic dosing oil-gas-liquid three-phase extraction device was established in Liaohe Oilfield, Panjin City, Liaoning Province, and the above-mentioned device was used to repair oil-contaminated soil in situ. The steps are as follows.

1) Use the air compressor 1 to perform pneumatic shock cracking around the gas cracking/dosing well 6 for 3 hours at a pressure of 0.2-0.7 MPa;

2) Turn on the periodic dosing device 2 to inject nutrients and surfactants into the gas cracking/dosing well 6, dosing for 9 hours, and then stop gas cracking and dosing for 12 hours, this operation is a cycle;

3) At the same time as dosing, start the suction pump 7 to pump the petroleum pollutants to the ground surface through the suction pipe 18 in the suction well 17, and then enter the gas-liquid separation device 8; the separated gas phase is passed into the gas processing device 10 for treatment. After passing through the gas recovery device 11 or discharge; the separated liquid phase is passed into the water-oil separation device 13 to be separated into an oil phase and a water phase, the oil phase is passed into the oil phase recovery device 14 for processing, and the water phase is passed into the water phase processing device 15 for processing and then enters the water phase Recharging device 16;

4) When the oil-gas-liquid three-phase extraction system is turned on, repeat steps 1) and 2) for periodic dosing, and monitor the pH, COD, and petroleum hydrocarbon content of the suction well exudate in real time. When the pH value is 6- 9. Stop dosing when the COD is less than 100mg/L and the petroleum hydrocarbon content is less than 10mg/L.

Step 2) The nutritional elements are composed of nitrogen, phosphorus and trace elements, wherein the addition intensity of nitrogen and phosphorus is: the weight ratio of the carbon content of pollutants in the soil to nitrogen and phosphorus elements C:N:P is 100 : (4-7): (0.8-1.3); the trace elements in the nutrients are magnesium, iron, calcium, copper, cobalt, manganese, zinc, boron, molybdenum and selenium, and the weight ratio of the trace elements of carbon is 1: ( ^{10-8-10-3 )} .

The surfactant described in step 2) is a conventional surfactant, and its mass is 0.005-0.02 of the total mass of petroleum pollutants in the soil.

Claims (4)

1. dosing oil-gas-liquid three-phase extraction device periodically, it is characterized in that, this device is comprised of periodicity medicine system and oil-gas-liquid three-phase extraction system, periodically medicine system Air compressor (1) links to each other with control system (3) respectively with periodicity chemicals dosing plant (2), air compressor (1) links to each other with gas checking pipe (4), periodically chemicals dosing plant (2) links to each other with chemical feed pipe (5), and gas checking pipe (4) links to each other with gas checking/dosing well (6) respectively with chemical feed pipe (5); Suction pump (7) links to each other with suction tube (18) with gas-liquid separation device (8) respectively in the oil-gas-liquid three-phase extraction system, gas-liquid separation device (8) links to each other with delivery pump (12) with liquid rotary pump (9) respectively, liquid rotary pump (9), gas treatment equipment (10), gas concentration unit (11) links to each other successively, delivery pump (12) links to each other with water oil separating device (13), water oil separating device (13) links to each other with water treating apparatus (15) with oil phase retracting device (14) respectively, water treating apparatus (15) links to each other with water backflow device (16), and suction tube (18) links to each other with suction well (17).

2. based on the method for periodicity dosing oil-gas-liquid three-phase extraction device remedying oil-polluted soils claimed in claim 1, it is characterized in that, comprise the steps:

1) be under the 0.2-0.7MPa gas checking/dosing well (6) to be carried out the pneumatic 3h that shatters on every side with air compressor (1) at pressure;

2) open periodicity chemicals dosing plant (2) nutrient and surfactant are injected in gas checking/dosing well (6), dosing 9h,, then stopping gas checking and dosing 12h, this is operating as a cycle;

3) dosing is opened suction pump (7) and by the suction tube (18) in the suction well (17) petroleum pollution is drawn into ground surface simultaneously, enters gas-liquid separation device (8); Isolated gas phase passes into gas treatment equipment (10), passes through gas concentration unit (11) or discharging after processing; Isolated liquid phase passes into water oil separating device (13) and is separated into oil phase and water, and oil phase passes into oil phase retracting device (14) and processes, and water passes into water treating apparatus (15) and processes the laggard water backflow device (16) that enters;

4) when opening oil-gas-liquid three-phase extraction system, repeating step 1) and 2) carry out the periodicity dosing, pH, COD, the petroleum hydrocarbon content of Real-Time Monitoring suction well diffusate are when the pH value is 6-9, COD is less than 100mg/L, and petroleum hydrocarbon content stops dosing during less than 10mg/L.

3. according to the method for right 2 described remedying oil-polluted soils, it is characterized in that, step 2) described nutrient is comprised of nitrogen, P elements and trace element, and wherein nitrogen, phosphorus add intensity and is: the weight ratio C:N:P of the carbon element content of the pollutant in the soil and nitrogen, P elements is 100:(4-7): (0.8-1.3); Trace element in the nutrient is magnesium, iron, calcium, copper, cobalt, manganese, zinc, boron, molybdenum and selenium, and carbon is 1:(10 with the weight ratio of trace element ^-8-10 ^-3).

4. according to the method for right 2 described remedying oil-polluted soils, it is characterized in that step 2) described surfactant is conventional surfactants, its quality is the 0.005-0.02 of soil PetroChina Company Limited. pollutant gross mass.

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