Heat conduction reinforced in-situ aeration system for treating groundwater pollution and use method thereof

Abstract

The invention relates to the technical field of underground water treatment, in particular to a heat conduction reinforced in-situ aeration system for treating underground water pollution, which comprises a hot water circulation and hot steam generation system, a heat conduction pipe and an aeration well, the system comprises an underground cavity used for containing water, a chemical adding system used for injecting chemicals into the water-containing layer, and an extraction system used for extracting gas in the underground cavity and purifying the gas, and hot steam is injected into the pollution plume, so that the temperature around the pollution plume is increased, pollutant diffusion and the gas-liquid mass transfer rate are increased, the remediation range is expanded, and the air disturbance (AS) remediation efficiency is improved. The hot steam also forms an airflow barrier on the outer side of the pollution plume to separate the pollution plume from the outside, so that the migration and diffusion of pollutants are avoided; and hot water is introduced into the heat conducting pipe, so that the temperature of underground water is increased, the volatilization efficiency is improved, and the utilization rate of heated water is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of groundwater treatment, in particular to an in-situ aeration system for treating groundwater pollution by heat conduction enhancement, and also to a method for using the in-situ aeration system for treating groundwater pollution by heat conduction enhancement. Background Art

[0002] Groundwater pollution air disturbance remediation technology (AS) is an in-situ remediation technology for removing volatile organic compounds from groundwater and soil. Pollutants are removed mainly from the following three aspects: stripping soluble volatile organic pollutants; accelerating the volatilization of adsorbed organic matter under the groundwater table; and causing aerobic biodegradation of volatile and adsorbed organic pollutants.

[0003] Thermal steam remediation technology is mainly used to treat groundwater contaminated by organic pollutants. For example, the removal effect of petrochemical contaminated sites contaminated by organic pollutants such as benzene and toluene is obvious. Organic pollutants are volatile. After hot steam is injected into the ground, heat exchange will occur with groundwater, increasing their volatilization rate and separating them from groundwater. At present, there are many cases of using hot steam to remediate groundwater at home and abroad. For example, a project in Shanghai used hot steam enhanced remediation technology to treat 25,000 cubic meters of groundwater contaminated by oil. However, if only hot steam is used for remediation, the impact range is small, the temperature fluctuation range is large, the remediation time is long, and the heat energy is wasted in the process of producing hot steam, which increases the cost. How to efficiently use thermal energy to enhance air disturbance (AS) remediation technology, shorten the remediation time and improve the remediation efficiency still needs further research. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in order to overcome the problem of how to efficiently utilize thermal energy to enhance air disturbance (AS) remediation technology in the prior art, shorten the remediation time, and improve the remediation efficiency, which still needs further research, a heat conduction enhanced in-situ aeration system for treating groundwater pollution is provided.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a heat conduction enhanced in-situ aeration system for treating groundwater pollution, comprising:

[0006] A hot water circulation and hot steam generation system, comprising a water storage tank, a steam boiler, a gas-liquid separator, a heat conducting pipe and an aeration well, wherein the water storage tank is used to provide water to the steam boiler, the output end of the water storage tank is connected to the input end of the steam boiler, the steam boiler is used to heat water, the output end of the steam boiler is connected to the gas-liquid separator, the steam output end of the gas-liquid separator is connected to the input end of the aeration well, the hot water output end of the gas-liquid separator is connected to the input end of the heat conducting pipe, the output end of the heat conducting pipe is connected to the water storage tank, the gas-liquid separator is used to separate hot water and steam, the aeration well extends to the contaminated plume of the aquifer in the underground cavity, and the aeration well is used to spray hot steam into the aquifer In the pollution plume, the heat pipe passes through the pollution plume of the underground aquifer. The heat pipe is used to exchange heat with the pollution plume. By injecting hot steam into the pollution plume, the temperature around the pollution plume is increased, the diffusion of pollutants and the gas-liquid mass transfer rate are accelerated, the repair range is expanded, and the air disturbance (AS) repair efficiency is improved. The hot steam also forms an airflow barrier on the outside of the pollution plume to separate the pollution plume from the outside and avoid the migration and diffusion of pollutants. By introducing hot water into the heat pipe, the temperature of the groundwater is increased, the volatilization efficiency is improved, and the utilization rate of the heated water is improved. The cooled hot water is returned to the water storage tank through the pipeline as a supplementary water source and reused to form a water cycle.

[0007] A dosing system for injecting chemicals into the aquifer,

[0008] and an extraction system for extracting gas from the underground cavity and purifying the gas.

[0009] In order to solve the problem of low steam ejection range of the aeration well, the aeration well is further provided with aeration heads spaced apart along the axis direction thereof, and a liquid level sensor is arranged on the water storage tank.

[0010] The hot water circulation and hot steam generation system further comprises a water inlet pump, the output end of the water inlet pump is connected to the input end of the water storage tank, and the input end of the water inlet pump is connected to the output end of the heat conduction pipe.

[0011] In order to solve the problem of how to arrange the dosing system, the dosing system further includes a drug injection well, a dosing pump and a drug storage box. The bottom of the drug injection well is deep in the aquifer, and a drug outlet hole is opened on the drug injection well. The output end of the drug reaction box is connected to the input end of the dosing pump, and the output end of the dosing pump is connected to the input end of the drug injection well. The addition of drugs can ensure efficient removal of pollutants, while reducing energy consumption and saving costs; or injecting activating agents (persulfate) or surfactants (sodium dodecylbenzene sulfonate) into the formation to achieve chemical and physical synergistic remediation of pollutants and improve the pollutant removal rate.

[0012] In order to solve the problem of how to arrange the extraction system, the extraction system further includes a pumping well, a pumping pump, a reagent reaction box and an activated carbon adsorption tank. The lower end of the pumping well extends into the underground cavity and is higher than the liquid level of the aquifer. The output end of the pumping well is connected to the input end of the pumping pump, the output end of the pumping pump is connected to the input end of the reagent reaction box, and the output end of the reagent reaction box is connected to the input end of the activated carbon adsorption tank. The polluted gas is treated and discharged after meeting the standards.

[0013] The aeration system further includes a monitoring system, which includes a monitoring well. The monitoring well extends into the aquifer and is provided with water inlet holes spaced along its axial direction. The monitoring well is used to detect the concentration distribution of pollutants and reagents.

[0014] A method for using a heat conduction enhanced in-situ aeration system for treating groundwater pollution comprises the following steps:

[0015] The water in the water storage tank is supplied to the steam boiler, which heats the water to 100°C and transmits the heated water to the gas-liquid separator, which separates the heated water into hot steam and hot water. The hot steam is sprayed into the pollution plume of the aquifer in the underground cavity through the aeration well, so that the volatile and semi-volatile pollutants in the pollution plume enter the gas, and the hot water exchanges heat with the pollution plume in the aquifer through the heat pipe and returns to the water storage tank again, forming a water cycle;

[0016] The dosing system uses a dosing pump to transfer the reagents in the reagent storage tank to the reagent injection well, and the reagent injection well injects the reagents into the contaminated plume. The ratio of ethanol, water and benzene at the azeotropic point is 23:23:54, and the formation temperature is 5°C higher than the boiling point of the pollutants at the azeotropic point.

[0017] The vacuum pump of the extraction system is started to extract polluted gas through the vacuum well and input the polluted gas into the reagent reaction box. After being processed in the reagent reaction box, the polluted gas is input into the activated carbon adsorption tank.

[0018] The monitoring wells in the monitoring system extract water from the aquifer and detect the concentration distribution of pollutants and pharmaceuticals.

[0019] The beneficial effects of the present invention are as follows: a hot water circulation and hot steam generating system provided by the present invention increases the temperature around the pollution plume by injecting hot steam into the pollution plume, accelerates the diffusion of pollutants and the gas-liquid mass transfer rate, expands the repair range, and improves the air disturbance (AS) repair efficiency. The hot steam also forms an airflow barrier on the outside of the pollution plume to separate the pollution plume from the outside and avoid the migration and diffusion of pollutants. By introducing hot water into the heat conduction pipe, the temperature of the groundwater is increased, the volatilization efficiency is improved, and the utilization rate of the heated water is improved. The cooled hot water is returned to the water storage tank through the pipeline as a supplementary water source and is reused to form a water cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0021] Figure 1 It is a schematic diagram of the structure of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the hot water circulation and hot steam generation system of the present invention;

[0023] Figure 3 It is a structural schematic diagram of the dosing system of the present invention;

[0024] Figure 4 It is a schematic diagram of the structure of the extraction system of the present invention.

[0025] In the figure: 1, hot water circulation and hot steam generation system, 11, water storage tank, 111, liquid level sensor, 12, steam boiler, 13, gas-liquid separator, 14, heat transfer pipe, 15, aeration well, 151, aeration head, 16, water inlet pump;

[0026] 2. Dosing system, 21. Drug injection well, 211. Drug outlet, 22. Dosing pump, 23. Drug storage tank;

[0027] 3. Extraction system, 31. Air extraction well, 32. Air extraction pump, 33. Reagent reaction box, 34. Activated carbon adsorption tank;

[0028] 4. Monitoring system, 41. Monitoring wells;

[0029] 5. Aquifer, 51. Pollution plume. DETAILED DESCRIPTION

[0030] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0031] like Figure 1 The present invention is a schematic structural diagram of an in-situ aeration system for treating groundwater contamination by heat conduction enhancement, comprising:

[0032] like Figure 1 , 2As shown, the hot water circulation and hot steam generation system 1 includes a water storage tank 11, a steam boiler 12, a gas-liquid separator 13, a heat pipe 14 and an aeration well 15. The water storage tank 11 is used to provide water to the steam boiler 12. The output end of the water storage tank 11 is connected to the input end of the steam boiler 12. The steam boiler 12 is used to heat water. The output end of the steam boiler 12 is connected to the gas-liquid separator 13. The steam output end of the gas-liquid separator 13 is connected to the input end of the aeration well 15. The hot water output end of the gas-liquid separator 13 is connected to the input end of the heat pipe 14. The output end of the heat conducting pipe 14 is connected to the water storage tank 11, the gas-liquid separator 13 is used to separate hot water and steam, the aeration well 15 extends to the pollution plume 51 of the aquifer 5 in the underground cavity, the aeration well 15 is used to spray hot steam into the pollution plume 51 of the aquifer 5, the heat conducting pipe 14 passes through the pollution plume 51 of the underground aquifer 5, and the heat conducting pipe 14 is used to exchange heat with the pollution plume 51; the aeration well 15 is provided with aeration heads 151 spaced apart along the axial direction thereof, and the water storage tank 11 is provided with a liquid level sensor 111.

[0033] Through the design of the heat pipe 14, hot water passes through the pollution plume 51 and exchanges heat with the pollution plume 51, which is beneficial for the groundwater to quickly rise to the preset temperature, realize the efficient removal of volatile and semi-volatile organic pollutants, shorten the repair time, and flow back to the water storage tank 11. The residual heat of the hot water can increase the initial temperature of the water heated by the steam boiler 12, reduce its energy consumption, and improve the utilization rate of water. The hot water in the heat pipe 14 increases the temperature of the pollution plume, accelerates the volatilization efficiency of semi-volatile organic pollutants, improves the air disturbance (AS) repair efficiency, and expands the air disturbance (AS) repair range.

[0034] The aeration well 15 is arranged around the pollution plume 51 , and the hot steam ejected from the aeration well 15 forms an airflow barrier around the pollution plume 6 , isolating the pollution plume 6 from the outside world and preventing the migration and diffusion of pollutants.

[0035] A pressure regulating valve, a gas flow meter and a pressure sensor are also installed between the gas-liquid separation device 13 and the aeration head 151 to keep the gas pressure at the outlet of the aeration head 14 stable.

[0036] The hot steam contacts the pollutants and increases the formation temperature, accelerating the diffusion of pollutants and the gas-liquid mass transfer rate.

[0037] The hot water circulation and hot steam generation system 1 includes a water inlet pump 16, the output end of the water inlet pump 16 is connected to the input end of the water storage tank 11, the input end of the water inlet pump 16 is connected to the output end of the heat pipe 14, and the input end of the water inlet pump 16 is also connected to a water source, which can be the water consumed in the water storage tank 11.

[0038] like Figure 1 , 3As shown, the dosing system 2 is used to inject the agent into the aquifer 5. The dosing system 2 includes a agent injection well 21, a dosing pump 22 and a agent storage box 23. The bottom of the agent injection well 21 is deep in the aquifer 5. A drug outlet hole 211 is opened on the agent injection well 21. The output end of the agent reaction box 33 is connected to the input end of the dosing pump 22, and the output end of the dosing pump 22 is connected to the input end of the agent injection well 21. The agent can improve the degradation efficiency of organic pollutants and reduce the generation of secondary pollutants.

[0039] The reagents include azeotropic reagents (such as ethanol, n-hexanol, etc.) and activating reagents (persulfate) or surfactants (sodium dodecylbenzene sulfonate). The azeotropic reagents (such as ethanol, n-hexanol, etc.) are injected into the formation through the reagent injection well 21. The boiling point of the pollutants is reduced by adding reagents such as ethanol or n-hexanol, and the formation temperature design parameters are reduced. While ensuring the efficient removal of pollutants, energy consumption is reduced and costs are saved; the activating agent or surfactant can achieve chemical and physical synergistic remediation of pollutants, improve the removal rate of pollutants, use the thermal energy of hot steam and hot water to thermally activate persulfate, accelerate the degradation rate of organic pollutants, improve the air disturbance (AS) remediation efficiency, and do not produce secondary pollution.

[0040] Principle of the agent: Thermally activated persulfate produces sulfate radicals, which have a high reduction potential of 2.6V, only slightly lower than hydroxyl radicals (2.9V), but are more stable than hydroxyl radicals in water. In addition, sulfate radicals exhibit a non-selective oxidation mode and can quickly decompose a variety of organic pollutants in water. Agent selection can be used separately or in series according to specific circumstances.

[0041] like Figure 1 , 4 As shown, the extraction system 3 is used to extract the gas in the underground cavity and purify the gas; the extraction system 3 includes a suction well 31, a suction pump 32, a reagent reaction box 33 and an activated carbon adsorption tank 34. The lower end of the suction well 31 extends into the underground cavity and is higher than the liquid level of the aquifer 5. The output end of the suction well 31 is connected to the input end of the suction pump 32, the output end of the suction pump 32 is connected to the input end of the reagent reaction box 33, and the output end of the reagent reaction box 33 is connected to the input end of the activated carbon adsorption tank 34. The polluted gas is treated and discharged after meeting the standards. The reagent reaction box 33 is equipped with substances that react with pollutants so that the pollutants are converted into harmless substances through chemical reactions. The activated carbon adsorption tank 34 is provided with activated carbon for adsorbing harmful substances in the gas.

[0042] like Figure 1As shown, the aeration system also includes a monitoring system 4, which includes a monitoring well 41. The monitoring well 41 extends into the aquifer 5. The monitoring well 41 is provided with water inlet holes spaced along its axial direction. The monitoring well 41 is used to detect the concentration distribution of pollutants and reagents. By monitoring the water of the pollution plume 51, the type of pollutant can be detected, and the corresponding reactants are prepared according to the type of pollutant to react chemically with the pollutant to generate non-polluting substances; by detecting the concentration of the reagent, the reagent content is controlled, thereby adjusting the surface tension or viscosity of the groundwater.

[0043] A method for using a heat conduction enhanced in-situ aeration system for treating groundwater pollution comprises the following steps:

[0044] The water in the water storage tank 11 is supplied to the steam boiler 12. The steam boiler 12 heats the water to 100° C. and transmits the heated water to the gas-liquid separator 13. The gas-liquid separator 13 separates the heated water into hot steam and hot water. The hot steam is sprayed into the pollution plume 51 of the aquifer 5 in the underground cavity through the aeration well 15, so that the volatile and semi-volatile pollutants in the pollution plume 51 enter the gas. The hot water exchanges heat with the pollution plume 51 in the aquifer 5 through the heat pipe 14 and returns to the water storage tank 11 again, forming a water cycle.

[0045] The dosing system 2 inputs the agent in the agent storage box 23 into the agent injection well 21 through the dosing pump 22. The agent injection well 21 injects the agent into the pollution plume 51. At the azeotropic point, the ratio of ethanol, water and benzene is 23:23:54. At this time, the boiling points of the three are the lowest. As the remediation proceeds, the ratio of ethanol-water-benzene changes, and the boiling point temperature also increases. Benzene acts as an azeotropic agent. The azeotropic point is the position where ethanol, benzene and water are miscible. It is not only for the benzene-ethanol-water system, but also for the toluene-ethanol-water system. The formation temperature is 5°C higher than the boiling point of the pollutant at the azeotropic point. The ratio of ethanol-water-ethyl acetate is 9:8:83. The azeotropic boiling point of ethanol-water-ethyl acetate is 70.2°C. The formation is mainly a groundwater benzene contaminated area. It is ensured that when the agent is not optimally miscible, the temperature can reach the benzene-water azeotropic point of 63.3°C. Through the temperature change of the area and the change of the ratio of components in the agent mixing area, different pollutants in the water body can be synergistically removed to improve the cleaning efficiency.

[0046] The vacuum pump 32 of the extraction system 3 is started to extract the polluted gas through the vacuum well 31 and input the polluted gas into the reagent reaction box 33. After being processed by the reagent reaction box 33, the polluted gas is input into the activated carbon adsorption tank 34.

[0047] The monitoring well 41 in the monitoring system 4 extracts water from the aquifer 5 and detects the concentration distribution of pollutants and chemicals.

[0048] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A heat conduction enhanced in-situ aeration system for treating groundwater pollution, characterized in that: include: A hot water circulation and hot steam generation system (1) comprises a water storage tank (11), a steam boiler (12), a gas-liquid separator (13), a heat conducting pipe (14) and an aeration well (15), wherein the water storage tank (11) is used to provide water to the steam boiler (12), the output end of the water storage tank (11) is connected to the input end of the steam boiler (12), the steam boiler (12) is used to heat water, the output end of the steam boiler (12) is connected to the gas-liquid separator (13), the steam output end of the gas-liquid separator (13) is connected to the input end of the aeration well (15), and the hot water output of the gas-liquid separator (13) is connected to the input end of the aeration well (15). The end of the heat-conducting pipe (14) is connected to the input end of the heat-conducting pipe (14), the output end of the heat-conducting pipe (14) is connected to the water storage tank (11), the gas-liquid separator (13) is used to separate hot water and steam, the aeration well (15) extends into the pollution plume (51) of the aquifer (5) in the underground cavity, and the aeration well (15) is arranged around the pollution plume (51), the aeration well (15) is used to spray hot steam into the pollution plume (51) of the aquifer (5), the heat-conducting pipe (14) passes through the pollution plume (51) of the underground aquifer (5), and the heat-conducting pipe (14) is used to perform heat exchange with the pollution plume (51); A dosing system (2) for injecting a pharmaceutical agent into an aquifer (5), And an extraction system (3) for extracting gas from the underground cavity and purifying the gas.

2. The heat conduction enhanced in-situ aeration system for treating groundwater pollution according to claim 1, characterized in that: The aeration well (15) is provided with aeration heads (151) spaced apart along the axial direction thereof, and the water storage tank (11) is provided with a liquid level sensor (111).

3. The heat conduction enhanced in-situ aeration system for treating groundwater pollution according to claim 1, characterized in that: The hot water circulation and hot steam generation system (1) comprises a water inlet pump (16), the output end of the water inlet pump (16) is connected to the input end of the water storage tank (11), and the input end of the water inlet pump (16) is connected to the output end of the heat conduction pipe (14).

4. The heat conduction enhanced in-situ aeration system for treating groundwater pollution according to claim 1, characterized in that: The dosing system (2) comprises a drug injection well (21), a drug dosing pump (22) and a drug storage box (23); the bottom of the drug injection well (21) is deep in the aquifer (5); a drug outlet hole (211) is provided on the drug injection well (21); the output end of the drug reaction box (33) is connected to the input end of the drug dosing pump (22); and the output end of the drug dosing pump (22) is connected to the input end of the drug injection well (21).

5. The heat conduction enhanced in-situ aeration system for treating groundwater pollution according to claim 1, characterized in that: The extraction system (3) comprises an air extraction well (31), an air extraction pump (32), a reagent reaction box (33) and an activated carbon adsorption tank (34); the lower end of the air extraction well (31) extends into an underground cavity and is higher than the liquid level of the aquifer (5); the output end of the air extraction well (31) is connected to the input end of the air extraction pump (32); the output end of the air extraction pump (32) is connected to the input end of the reagent reaction box (33); and the output end of the reagent reaction box (33) is connected to the input end of the activated carbon adsorption tank (34).

6. The heat conduction enhanced in-situ aeration system for treating groundwater pollution according to claim 1, characterized in that: The aeration system also includes a monitoring system (4), wherein the monitoring system (4) includes a monitoring well (41), wherein the monitoring well (41) extends into the aquifer (5), wherein the monitoring well (41) is provided with water inlet holes spaced apart along its axial direction, and wherein the monitoring well (41) is used to detect the concentration distribution of pollutants and reagents.

7. A method for using the heat conduction enhanced in-situ aeration system for treating groundwater pollution according to any one of claims 1 to 6, characterized in that: The following steps are involved: The water in the water storage tank (11) is supplied to the steam boiler (12), the steam boiler (12) heats the water to 100° C. and transmits the heated water to the gas-liquid separator (13), the gas-liquid separator (13) separates the heated water into hot steam and hot water, wherein the hot steam is sprayed into the pollution plume (51) of the aquifer (5) in the underground cavity through the aeration well (15), so that the volatile and semi-volatile pollutants in the pollution plume (51) enter the gas, and the hot water exchanges heat with the pollution plume (51) in the aquifer (5) through the heat conduction pipe (14) and returns to the water storage tank (11) again, forming a water cycle; The dosing system (2) inputs the agent in the agent storage box (23) into the agent injection well (21) through the dosing pump (22), and the agent injection well (21) injects the agent into the contaminated plume (51), and the formation temperature is 5°C higher than the boiling point of the pollutant at the azeotropic point; The air pump (32) of the extraction system (3) is started to extract polluted gas through the air extraction well (31) and input the polluted gas into the reagent reaction box (33), and then input the polluted gas into the activated carbon adsorption tank (34) after being processed by the reagent reaction box (33); The monitoring well (41) in the monitoring system (4) extracts water from the aquifer (5) and detects the concentration distribution of pollutants and reagents.

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