Soil remediation process and equipment based on ex-situ chemical heating thermal desorption method

Abstract

The invention relates to a soil remediation process and equipment based on an ex-situ chemical heating thermal desorption method, and relates to the technical field of contaminated soil remediation, the soil remediation process comprises the following steps: 1, adding a chemical remediation reagent into soil; 2, pretreatment is conducted, specifically, the soil added with the chemical remediation reagent is stirred and preheated; 3, thermal desorption is conducted, specifically, the preheated soil is heated and desorbed, pollutants in the soil are gasified to generate pollution gas, and the pollution gas is separated from the soil; and 4, air cooling is conducted, specifically, cooling air is introduced into the soil obtained after thermal desorption, the soil is cooled, hot air is generated after the soil is cooled through the cooling air, and the hot air is separated from the soil. According to the soil remediation process, a chemical remediation technology and a thermal desorption remediation technology are organically combined, so that the separation amount of pollutants in the soil is increased, and the remediation effect of the soil is improved.

Description

Technical Field

[0001] The present application relates to the technical field of contaminated soil remediation, and in particular to a soil remediation process and equipment based on an ex situ chemical heating thermal desorption method. Background Art

[0002] At present, soil remediation is a complex process that aims to restore the normal function of contaminated soil. This process involves a variety of technologies and methods, mainly including physical, chemical and biological remediation technologies. Among them, the use of physical remediation technology and chemical remediation technology is more common. Physical remediation technology mainly removes or separates pollutants from the soil through physical processes, such as soil removal, thermal desorption, soil vapor extraction, mechanical ventilation, etc.; chemical remediation technology mainly removes or reduces pollutants in the soil by adding chemical substances to the soil through chemical reactions, including soil solidification, stabilization, leaching, oxidation-reduction, etc.

[0003] At present, chemical remediation technology mainly uses injection or agitator stirring to mix chemical reagents into the contaminated soil, but this method is only applicable to soils with good permeability. For clay soils with poor permeability, the remediation agent is difficult to diffuse, and the pollutants and the remediation agent are not in sufficient contact, resulting in a poor remediation effect. Summary of the invention

[0004] The present application provides a soil remediation process and equipment based on an ex situ chemical heating thermal desorption method, the purpose of which is to solve the problem of insufficient contact between chemical agents and soil in existing chemical remediation technologies and to improve the soil remediation effect.

[0005] In the first aspect, the present application provides a soil remediation process based on ex situ chemical heating thermal desorption method using the following technical solutions: A soil remediation process based on an ex situ chemical heating thermal desorption method comprises the following steps: a first step, adding a chemical remediation agent to the soil; a second step, pretreatment, stirring and preheating the soil to which the chemical remediation agent is added; a third step, thermal desorption, heating and desorbing the preheated soil to gasify pollutants in the soil to generate polluted gas, and separating the polluted gas from the soil; a fourth step, air cooling, introducing cooling air into the soil after thermal desorption to cool the soil, and generating hot air after the cooling air cools the soil, and the hot air is separated from the soil.

[0006] By adopting the above technical scheme, the contaminated soil is sequentially added with chemical remediation reagents, pretreated, thermally desorbed and cooled, wherein the chemical remediation reagents realize the chemical remediation of the soil; pretreatment, thermal desorption and cooling realize the thermal desorption remediation of the soil. Since the soil needs to be fully stirred in the pretreatment, thermal desorption and cooling stages, this can continuously increase the contact degree between the chemical reagents and the soil, and increase the effect of the chemical remediation technology; and the timely addition of chemical remediation can also speed up the gasification rate of pollutants, thereby improving the effect of thermal desorption remediation technology, which realizes the organic combination of soil chemical remediation technology and thermal desorption remediation technology. Chemical remediation technology and thermal desorption remediation technology complement each other, thereby increasing the separation amount of pollutants in the soil, and thus improving the soil remediation effect. Therefore, the soil remediation process can increase the mixing uniformity of chemical remediation agents and soil, and can increase the separation amount of pollutants in the soil, thereby increasing the soil remediation effect.

[0007] Optionally, the method further includes the following steps: In the fifth step, the polluted gas separated in the third step is mixed with the hot air separated in the fourth step, and the mixed gas is used for preheating the soil in the second step.

[0008] By adopting the above technical solution, since both the polluted gas and the hot air contain relatively high temperatures, the polluted gas and the hot air are directly mixed into a mixed gas with a relatively high temperature, and the mixed gas is used for preheating the soil to enable heat reflux, thereby reducing heat waste.

[0009] Optionally, the following steps are also included: In the fifth step, the polluted gas separated in the third step is heat exchanged with the hot air separated in the fourth step, and the temperatures of the polluted gas and the hot air are adjusted to be the same. The polluted gas and the hot air after the heat exchange are independently used for preheating the soil in the second step.

[0010] By adopting the above technical solution, since the hot air and the polluted gas have different compositions, in order to facilitate the subsequent purification treatment, the hot air and the polluted gas need to be used independently for preheating the soil, and in order to make the preheating of the soil uniform, the temperature of the polluted gas and the hot air is adjusted to be consistent through heat exchange. Such a step setting enables the polluted gas and the hot air to preheat the soil independently, so that the polluted gas and the hot air maintain independence during the preheating process, which provides convenience for the subsequent purification treatment.

[0011] Optionally, the fourth step also includes the following steps: cooling water cooling, cooling the soil by heat exchange with cooling water.

[0012] By adopting the above technical solution, since the air cooling speed is slow, when the concentration of polluted gas and smoke in the hot air reaches a certain level, the cooling water is started to cool down. At this time, the cooling water cooperates with the cooling air to accelerate the cooling of the soil.

[0013] Optionally, the fifth step also includes the following steps: exchanging heat between the cooling water after cooling the soil and the polluted gas separated in the third step and the hot air separated in the fourth step, adjusting the temperatures of the cooling water, the polluted gas and the hot air to the same, and independently using the cooling water, the polluted gas and the hot air after the heat exchange for preheating the soil in the second step.

[0014] By adopting the above technical solution, since cooling water has a large specific heat capacity, it will absorb more heat during the soil cooling process, so cooling water is used to preheat the soil. In order to ensure the uniformity of soil preheating, it is necessary to exchange heat among the three heating media so that the temperatures of cooling water, polluted gas and hot air are adjusted to the same.

[0015] Such a step setting further increases the heat recovery and reduces unnecessary energy loss.

[0016] Optionally, the fifth step also includes the following steps: after the cooling water preheats the soil in the second step, it flows back to the fourth step for heat exchange cooling of the soil.

[0017] By adopting the above technical solution, after the cooling water preheats the soil, the temperature of the cooling water will decrease. At this time, the cooling water can be reused in the cooling step to perform heat exchange cooling on the soil, which realizes the recycling of cooling water and reduces the consumption of cooling water.

[0018] In the second aspect, the present application provides a soil remediation device based on ex situ chemical heating thermal desorption method, which adopts the following technical solution: A soil remediation device based on an ex situ chemical heating thermal desorption method comprises a reagent adding device, a pretreatment device, a thermal desorption device and a cooling device, wherein the pretreatment device, the thermal desorption device and the cooling device are connected in sequence, and the reagent adding device is connected to the pretreatment device; further comprising a heat exchanger, wherein the pretreatment device, the thermal desorption device and the cooling device are all connected to the heat exchanger; further comprising a storage device, wherein the storage device is connected to the pretreatment device.

[0019] By adopting the above technical solution, firstly, the pretreatment equipment, the thermal desorption equipment and the cooling equipment are connected in sequence, so that the soil will undergo pretreatment, thermal analysis and cooling in sequence, thereby meeting the thermal desorption technical requirements of soil remediation.

[0020] Secondly, since the pretreatment equipment is connected to the reagent adding equipment, chemical remediation reagents can be added to the soil during the pretreatment stage. Since the soil is stirred during the pretreatment, thermal analysis and cooling stages, the mixing uniformity of the chemical remediation reagent and the soil can be increased, thereby improving the remediation effect of the chemical remediation reagent on the soil.

[0021] On this basis, the heat exchanger is set up, and the medium with higher temperature generated in the thermal desorption equipment and the cooling equipment flows into the heat exchanger for heat exchange, and then the medium after the heat exchange is completed flows into the pretreatment equipment, which can realize the preheating function of the soil in the pretreatment stage, and the medium after heating will flow into the storage equipment for on-site storage.

[0022] This achieves the combination of chemical remediation and thermal desorption remediation of the soil, so that the chemical remediation technology and thermal desorption remediation technology complement each other, thereby increasing the separation amount of pollutants in the soil, thereby improving the soil remediation effect.

[0023] Optionally, the pretreatment equipment includes a mixing tank and a soil turning mechanism, the mixing tank is arranged in a vertical direction, and a feed port is opened on the side wall of the mixing tank; the pharmaceutical adding equipment is connected to the mixing tank; a stirring mechanism for stirring the soil is arranged in the mixing tank; the soil turning mechanism includes a conveying pipe, the conveying pipe is vertically arranged on the outside of the mixing tank, a feed pipe is arranged at the lower end of the conveying pipe, and a return pipe is arranged at the upper end of the conveying pipe, and the feed pipe and the return pipe are both inclined in the vertical direction; the upper end of the feed pipe is connected to the bottom of the mixing tank, and the lower end of the feed pipe is connected to the mixing tank; the upper end of the return pipe is connected to the conveying pipe, and the lower end of the return pipe is connected to the mixing tank; a vertical feeder for conveying soil in the vertical direction is arranged in the conveying pipe.

[0024] By adopting the above technical solution, the mixing tank is used to contain soil, and the stirring mechanism is used to stir the soil, which satisfies the stirring function in the soil pretreatment stage. On this basis, a soil turning mechanism is arranged on the outside of the mixing tank. The feed pipe in the soil turning mechanism can guide the soil at the bottom of the mixing tank into the conveying pipe. Under the action of the vertical feeder in the conveying pipe, the soil will be vertically lifted along the conveying pipe, and then finally flow back from the return pipe to the top of the soil in the mixing tank, thus realizing the function of soil turning. The cooperation between the stirring mechanism and the soil turning mechanism can increase the stirring effect of the soil in the mixing tank.

[0025] Optionally, a discharge pipe is also provided at the upper end of the conveying pipe. The discharge pipe is inclined in the vertical direction, the upper end of the discharge pipe is connected to the conveying pipe, and the lower end of the discharge pipe is connected to the thermal desorption equipment; a closing component for closing or opening the discharge pipe is provided in the discharge pipe.

[0026] By adopting the above technical solution, the setting of the feed pipe realizes the transportation of soil between the conveying pipe and the thermal desorption device, thereby connecting the pretreatment device with the thermal desorption device, which can realize the transportation of soil between different devices. The setting of the closed component can control the opening and closing of the feed pipe, and then by controlling the closed component, the transportation of soil between the pretreatment device and the thermal desorption device can be controlled.

[0027] Optionally, the stirring mechanism includes a stirring main pipe and a plurality of stirring plates, the stirring main pipe is vertically arranged in the mixing tank, the upper end of the stirring main pipe is rotatably connected to the mixing tank, and the stirring main pipe is provided with a stirring driving member for driving the stirring main pipe to rotate; the stirring plates are arranged in a vertical direction, and a plurality of the stirring plates are arranged in sequence at intervals along the circumference of the stirring main pipe, and the stirring plates are connected to the outer wall of the stirring main pipe, a medicine cavity is opened in the stirring plate, a plurality of nozzles are arranged on the outside of the stirring plate, and the nozzles and the stirring main pipe are both connected to the medicine cavity; the stirring main pipe is connected to the medicine adding device.

[0028] By adopting the above technical solution, the stirring mechanism can achieve the function of stirring the soil through the coordinated setting of the stirring main pipe and a number of stirring plates. Secondly, the coordinated setting of the stirring main pipe, the stirring cavity in the stirring plate and the nozzle outside the stirring plate can achieve the addition of chemical repair agents. Therefore, the stirring mechanism has the function of stirring and adding chemical repair agents, which can improve the uniformity of mixing the chemical repair agents and the soil. In summary, the present application includes at least one of the following beneficial technical effects: 1. The soil remediation process of the present application organically combines chemical remediation technology and thermal desorption remediation technology, thereby increasing the separation amount of pollutants in the soil and further improving the soil remediation effect.

[0029] 2. The soil remediation process of the present application uses the recirculation of polluted gases, hot air and cooling water to preheat the soil, which can achieve heat recovery, thereby reducing unnecessary energy consumption and solving energy problems.

[0030] 3. The soil remediation equipment of the present application realizes chemical remediation and thermal desorption remediation of the soil through the combination of agent adding equipment, pretreatment equipment, thermal desorption equipment and cooling equipment. At the same time, the pretreatment equipment, thermal desorption equipment and cooling equipment can increase the uniformity of the mixing of chemical remediation agents and soil during normal operation, which can further realize the organic structure of chemical remediation technology and thermal desorption remediation technology and improve the soil remediation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the soil remediation process of Example 1 of the present application.

[0032] Figure 2 It is a schematic diagram of the overall structure of the soil remediation equipment of Example 4 of the present application.

[0033] Figure 3 It is a schematic diagram of the overall structure of the pretreatment equipment, thermal desorption equipment and cooling equipment of Example 4 of the present application.

[0034] Figure 4 It is a schematic cross-sectional structure diagram of the pretreatment equipment, thermal desorption equipment and cooling equipment of Example 4 of the present application.

[0035] Figure 5 It is a schematic diagram of the overall structure of the pretreatment equipment of Example 4 of the present application.

[0036] Figure 6 It is a schematic diagram of the overall structure of the stirring mechanism of Example 4 of the present application.

[0037] Figure 7 It is a schematic diagram of the overall structure of the closed component of this application.

[0038] In the figure, 1, pretreatment equipment; 11, mixing tank; 111, feed port; 112, first air outlet pipe; 12, stirring mechanism; 121, stirring main pipe; 122, stirring drive member; 123, stirring plate; 1231, reagent cavity; 1232, nozzle; 124, connecting pipe; 13, soil turning mechanism; 131, conveying pipe; 132, feed pipe; 133, return pipe; 134, vertical feeder; 135, feed pipe; 136, closing assembly; 1361, driving spindle; 1362, closing drive member; 1363, closing plate; 14, preheating Mechanism; 141, first spiral tube; 142, second spiral tube; 2, thermal desorption equipment; 21, heating tank; 22, desorption tank; 221, polluted air pipe; 222, first stirring member; 23, first conveying mechanism; 3, cooling equipment; 31, cooling tank; 311, second stirring member; 312, cooling air pipe; 313, hot air pipe; 32, second conveying mechanism; 33, water cooling tank; 331, water inlet pipe; 332, water outlet pipe; 4, reagent adding equipment; 5, heat exchanger; 61, first storage tank; 62, second storage tank; 63, third storage tank. DETAILED DESCRIPTION

[0039] The following is combined with Figure 1 -Attached Figure 7 , further details of this application are given.

[0040] Example 1: A soil remediation process based on ex situ chemical heating thermal desorption method, referring to Figure 1 , including the following steps: The first step is to add chemical remediation agents to the soil and preliminarily stir the soil to allow the chemical remediation agents to fully contact the soil.

[0041] Specifically, chemical remediation agents are selected according to the actual pollution situation. Chemical remediation agents can be a combination of one or more of catalysts, cosolvents, oxidants, reductants, acid-base regulators, stabilizers, surfactants or chelating agents. Among them, catalysts are used to accelerate the decomposition and transformation of non-humans under heating conditions, thereby improving the efficiency of thermal desorption; cosolvents can help some non-volatile pollutants to vaporize at lower temperatures, thereby improving the removal degree of pollutants; oxidants can promote the oxidation of pollutants at high temperatures, increase the volatility of pollutants or convert them into a more easily handled form; reductants can effectively remove some pollutants that require reducing conditions to be effectively removed; acid-base regulators are used to adjust the pH of the soil, change the chemical form of pollutants, and make pollutants more easily volatilized under thermal desorption; stabilizers can improve the stability of the chemical form of pollutants, so that pollutants do not undergo chemical reactions and are directly vaporized; surfactants can help change the surface characteristics of some pollutants and increase the dispersibility of pollutants in the gas phase; chelating agents can combine with pollutants to form stable compounds, thereby increasing volatility during the thermal desorption process.

[0042] The second step is pretreatment, in which the soil with added chemical reagents is pretreated.

[0043] Specifically, the soil is stirred and preheated.

[0044] On the one hand, the stirring setting can ensure sufficient contact between the soil and the chemical remediation reagent; on the other hand, stirring can increase the uniformity of soil heating; in addition, the combination of preheating and stirring can adjust the moisture content and particle size of the soil to meet the requirements of subsequent thermal desorption.

[0045] The third step is thermal desorption, which is to perform thermal desorption on the soil after pretreatment.

[0046] Specifically, the soil is sent to the corresponding thermal desorption equipment, the soil is stirred and heated, the pollutants in the soil are gasified, thereby generating polluted gas, and the polluted gas is separated from the soil and discharged. Most of the pollutants in the soil can be separated by thermal desorption.

[0047] The fourth step is air cooling, which is used to cool the soil after thermal desorption.

[0048] Specifically, the soil is stirred and cooling air is introduced into the soil, so that the cooling air fully contacts the soil and exchanges heat, thereby cooling the soil. In this process, the cooling air generates hot air after cooling the soil, and the hot air is separated from the soil and discharged.

[0049] When cooling air is passed into the soil, the polluted gas remaining in the soil will be carried by the cooling air and separated from the soil, thereby reducing the residual pollutants in the soil and further reducing the possibility of secondary pollution.

[0050] When cooling air is passed into the soil, due to the high temperature of the soil, the organic matter in the soil will produce a micro-combustion reaction after coming into contact with the cooling air. The high-temperature flue gas produced by the micro-combustion will be carried by the hot air after heat exchange and separated from the soil, which can further achieve the desorption and desorption of pollutants in the soil, thereby reducing the residual pollutants in the soil.

[0051] The fifth step is heat reflux, which returns the heat of the polluted gas and the hot air to the soil in the second step to achieve preheating of the soil in the second step.

[0052] The specific steps include: S1, gas mixing: mixing the polluted gas separated in the third step with the hot air separated in the fourth step; S2, gas reflow: The mixed gas is used for soil preheating in the second step.

[0053] Specifically, since the temperatures of polluted gas and hot air are both high, both can be used to preheat the soil, which can achieve heat recovery and reduce energy waste. However, the temperatures of polluted gas and hot air are different. In order to make the soil preheated evenly, the polluted gas and hot air are mixed, and the temperature of the mixed gas is uniform, which can make the soil preheated evenly.

[0054] After the mixed gas has preheated the soil, the mixed gas is sent to a storage device for storage or to a condensation device or exhaust gas treatment device for exhaust gas treatment to ensure that the mixed gas is harmlessly treated.

[0055] The implementation principle of the embodiment of the present application is: adding chemical remediation reagents to the contaminated soil, pretreatment, thermal desorption and cooling in sequence, wherein the chemical remediation reagent realizes chemical remediation of the soil; pretreatment, thermal desorption and cooling realize thermal desorption remediation of the soil.

[0056] Since the soil needs to be fully stirred during the pretreatment, thermal desorption and cooling stages, the contact between chemical reagents and soil can be continuously increased, thereby increasing the effect of chemical remediation technology. The addition of chemical remediation agents can also speed up the gasification rate of pollutants, thereby improving the effect of thermal desorption remediation technology. This realizes the organic combination of soil chemical remediation technology and thermal desorption remediation technology. Chemical remediation technology and thermal desorption remediation technology complement each other, thereby increasing the separation amount of pollutants in the soil and thus improving the soil remediation effect.

[0057] Example 2: A soil remediation process based on ex situ chemical heating thermal desorption method. The difference between this example and Example 1 is that the fifth step includes the following steps: S1. Gas heat exchange: The polluted gas separated in the third step is heat exchanged with the hot air separated in the fourth step, and the temperatures of the polluted gas and the hot air are adjusted to be the same or similar.

[0058] S2. Gas reflux: The polluted gas and hot air after heat exchange are used independently for preheating the soil in the second step.

[0059] Specifically, since the components of the polluted gas and the hot air are different, the subsequent purification methods of the polluted gas and the hot air are different. Directly mixing the polluted gas and the hot air is not convenient for subsequent purification treatment, so the polluted gas and the hot air are exchanged through heat exchange, so that when the soil is preheated in the second step, the temperatures of the polluted gas and the hot air can be the same or similar, thereby improving the uniformity of soil preheating in the second step.

[0060] After the polluted gas and the hot air have completed preheating the soil in the second step, the polluted air and the hot air are stored independently of each other or purified independently of each other.

[0061] The implementation principle of the embodiment of the present application is: to achieve heat exchange between polluted gas and hot air by means of heat exchange, so that the polluted gas and hot air can preheat the soil independently of each other, so that the polluted gas and hot air maintain independence during the preheating process, which provides convenience for subsequent purification treatment.

[0062] Example 3: A soil remediation process based on ex situ chemical heating thermal desorption. The difference between this example and Example 2 is that the fourth step also includes the following steps: cooling water cooling, cooling the soil by heat exchange with cooling water.

[0063] Specifically, cooling water is passed into the pipe, and the pipe is in contact with the soil. At this time, the cooling water exchanges heat with the soil to achieve rapid cooling of the soil.

[0064] When the cooling air cools the soil, the hot air after heat exchange will carry the residual pollutant gas and the smoke produced by the micro-combustion reaction away from the soil. When it is detected that the concentration of pollutant gas and smoke in the hot air after heat exchange is low or there is no pollutant gas and smoke, the cooling water is started to cool down. The cooling water and cooling air cooperate with each other to accelerate the cooling speed of the soil.

[0065] The fifth step includes the following steps: S1, gas heat exchange and gas-liquid heat exchange: heat exchange the cooling water after heat exchange cooling, the polluted gas separated in the third step and the hot air separated in the fourth step, and adjust the temperatures of the cooling water, the polluted gas and the hot air to the same or similar levels; S2. Gas-liquid reflux: The cooling water, polluted gas and hot air after heat exchange are independently used for preheating the soil in the second step.

[0066] S3, liquid reflow: After the cooling water in step S2 preheats the soil in the second step, the cooling water exchanges heat with the soil, the cooling water temperature decreases, and the cooled cooling water is recirculated to the fourth step for heat exchange cooling of the soil.

[0067] The implementation principle of the embodiment of the present application is: in the fourth step, cooling water cooling is added, and the cooling water cooperates with the cooling air to increase the cooling rate of the soil. In the fifth step, after the cooling water exchanges heat with the polluted gas and the hot air, the cooling water can preheat the soil in the second step, and after the preheating is completed, the cooling water can be used to cool the soil in the fourth step, which realizes the recycling of cooling water. Therefore, the setting of cooling water not only improves the cooling efficiency of the soil, but also increases the sustainability of the entire process through the recycling of energy and resources.

[0068] Example 4, a soil remediation device based on ex situ chemical heating thermal desorption method, referring to Figure 2 and Figure 3 , including: pretreatment equipment 1, thermal desorption equipment 2 and cooling equipment 3, which are connected in sequence. This enables the soil to be pretreated, thermally desorbed and cooled in sequence, which can meet the requirements of the soil remediation process based on the ex situ chemical heating thermal desorption method.

[0069] Reference Figure 3 and Figure 4 The pretreatment equipment 1 includes a mixing tank 11, a stirring mechanism 12 and a soil turning mechanism 13.

[0070] Reference Figure 3 and Figure 4The mixing tank 11 is arranged in the vertical direction, the stirring mechanism 12 is arranged in the mixing tank 11, a feed port 111 is provided on the side wall of the mixing tank 11, a first air outlet pipe 112 is provided at the upper end of the mixing tank 11, and the first air outlet pipe 112 is connected to the upper end of the mixing tank 11, and a reagent adding device 4 is also provided on the mixing tank 11. Soil is added into the mixing tank 11 through the feed port 111, and then a chemical remediation agent is added into the soil through the reagent adding device 4, and the stirring mechanism 12 can stir the soil and the chemical remediation agent in the mixing tank 11, so that the soil and the chemical remediation agent can be fully contacted, and the first air outlet pipe 112 can discharge the water vapor generated by preheating and the gas generated by the reaction of the chemical remediation agent and the pollutant.

[0071] Reference Figure 5 and Figure 6 The stirring mechanism 12 includes a stirring main pipe 121, which is arranged in a vertical direction. The upper end of the stirring main pipe 121 is rotatably connected to the mixing tank 11. The stirring main pipe 121 is connected to a stirring driving member 122, and the stirring driving member 122 adopts a motor or a gear transmission structure driven by a motor.

[0072] Reference Figure 5 and Figure 6 The reagent adding device 4 is disposed on the stirring main pipe 121 , and the reagent adding device 4 is in communication with the stirring main pipe 121 . The reagent adding device 4 can inject the chemical repair reagent into the stirring main pipe 121 .

[0073] Reference Figure 4 and Figure 6 The stirring mechanism 12 further includes a plurality of stirring plates 123, which are located in the mixing tank 11. The plurality of stirring plates 123 are arranged in the vertical direction, and the plurality of stirring plates 123 are evenly spaced along the circumference of the stirring main pipe 121. A medicine cavity 1231 is provided in the stirring plate 123, and a plurality of nozzles 1232 are arranged outside the stirring plate 123, and the nozzles 1232 are connected to the medicine cavity 1231. A connecting pipe 124 is arranged between the stirring plate 123 and the stirring main pipe 121, and the two ends of the connecting pipe 124 are respectively connected to the stirring main pipe 121 and the corresponding medicine cavity 1231.

[0074] Reference Figure 4 and Figure 6When the stirring driving member 122 drives the stirring main pipe 121 to rotate, the plurality of stirring plates 123 rotate around the stirring main pipe 121, thereby realizing the stirring function of the concrete in the mixing tank 11. During the stirring process, the agent adding device 4 injects the chemical repair agent into the stirring main pipe 121, which makes the chemical repair agent flow into the agent cavity 1231 in the corresponding stirring plate 123 under high pressure, and under high pressure, the chemical repair agent is sprayed out through the nozzle 1232 on the stirring plate 123, and then the corresponding chemical repair agent can be added to the soil. Therefore, the cooperation of the stirring mechanism 12 and the agent adding device 4 can add the chemical repair agent to the soil, stir the soil, and improve the mixing uniformity of the chemical repair agent and the soil.

[0075] Reference Figure 5 The preheating mechanism 14 includes a first heating tube group, which includes three first spiral tubes 141, and the three first spiral tubes 141 are all wound around the outside of the mixing tank 11. The heating medium is introduced into the three first spiral tubes 141, so that the soil in the mixing tank 11 can be preheated by heat exchange. Therefore, the soil can be pretreated by the cooperation of the first heating tube group and the stirring mechanism 12.

[0076] Reference Figure 4 and Figure 5 The soil turning mechanism 13 includes a conveying pipe 131, which is located outside the mixing tank 11 and arranged in a vertical direction. A feed pipe 132 is arranged at the lower end of the conveying pipe 131, which is located at the lower side of the mixing tank 11 and arranged obliquely in the vertical direction. The upper end of the feed pipe 132 is connected to the bottom of the mixing tank 11, and the lower end of the feed pipe 132 is connected to the conveying pipe 131. When the mixing tank 11 is loaded with soil, the soil will enter the conveying pipe 131 through the feed pipe 132 under the action of its own gravity. A return pipe 133 is also arranged at the upper end of the conveying pipe 131, which is arranged obliquely in the vertical direction, the upper end of the return pipe 133 is connected to the conveying pipe 131, and the lower end of the return pipe 133 is connected to the side wall of the mixing tank 11. A vertical feeder 134 is provided in the conveying pipe 131 . The vertical feeder 134 adopts a screw feeder or an elevator. The feed port 111 of the vertical feeder 134 is connected to the feed pipe 132 , and the discharge port of the vertical feeder 134 is connected to the return pipe 133 .

[0077] Reference Figure 4 and Figure 5In the coordinated arrangement of the vertical feeder 134, the feed pipe 132 and the return pipe 133, the soil in the mixing tank 11 will flow from the feed pipe 132 into the delivery pipe 131, and under the action of the vertical feeder 134, the soil will be lifted in the vertical direction, and then the soil will flow back from the return pipe 133 to the uppermost side of the soil in the mixing tank 11, which can realize the turning of the soil. Therefore, the coordination of the soil turning mechanism 13 and the stirring mechanism 12 can improve the stirring effect of the soil and improve the mixing uniformity of the soil and the chemical repair agent.

[0078] Reference Figure 5 The preheating mechanism 14 further includes a second heating tube group, which includes three second spiral tubes 142, and the three second spiral tubes 142 are wound around the outside of the conveying tube 131. The heating medium is introduced into the three second spiral tubes 142, so that the soil in the conveying tube 131 can be heated, thereby ensuring that the soil is heated evenly.

[0079] Reference Figure 4 and Figure 5 A feed pipe 135 is also provided at the upper end of the delivery pipe 131. The feed pipe 135 is tilted in the vertical direction. The upper end of the feed pipe 135 is connected to the delivery pipe 131, and the lower end of the feed pipe 135 is connected to the thermal desorption device 2. Therefore, under the transportation of the vertical feeder 134, the soil in the pretreatment device 1 will pass through the feed pipe 132, the delivery pipe 131 and the feed pipe 135 in sequence, and then enter the thermal desorption device 2 to achieve thermal desorption of the soil.

[0080] Reference Figure 3 and Figure 5 A sealing component 136 is provided in both the return pipe 133 and the discharge pipe 135 , and the sealing component 136 in the return pipe 133 and the sealing component 136 in the discharge pipe 135 have the same structure.

[0081] Reference Figure 5 and Figure 6 , this embodiment is described by taking the closing assembly 136 in the feeding tube 135 as an example: the closing assembly 136 includes a driving spindle 1361, the driving spindle 1361 is arranged in the horizontal direction, and the two ends of the driving spindle 1361 are respectively connected to the two inner side walls of the feeding tube 135 for rotation, and the driving spindle 1361 is coaxially connected with a closing driving member 1362, and the closing driving member 1362 adopts a motor. A plurality of closing plates 1363 are arranged on the outer side wall of the driving spindle 1361, and the plurality of closing plates 1363 are arranged in sequence along the circumference of the driving spindle 1361. Both sides of the closing plates 1363 in the length direction are slidably connected to the inner side walls corresponding to the feeding tube 135, and one side of the closing plates 1363 in the width direction is connected to the driving spindle 1361.

[0082] Reference Figure 4 and Figure 5The corresponding feed pipe 135 can be closed by the cooperation of the driving main shaft 1361 and the plurality of closing plates 1363. In particular, when the closing driving member 1362 stops, some soil will remain between the driving main shaft 1361 and the conveying pipe 131 along the length direction of the feed pipe 135. Therefore, the cooperation of this part of soil and the closing assembly 136 can further improve the sealing performance of the feed pipe 135. When the closing driving member 1362 drives the driving main shaft 1361 to rotate, the plurality of closing plates 1363 rotate to realize the conveying of soil, which enables the soil to be conveyed in the feed pipe 135.

[0083] Reference Figure 5 and Figure 6 , and then through the cooperation of the closing component 136 in the return pipe 133 and the closing component 136 in the discharge pipe 135, it is possible to choose to open the return pipe 133 or the discharge pipe 135, and then in the pretreatment stage, the discharge pipe 135 is closed and the return pipe 133 is opened, so as to realize the turning of the soil. When the pretreatment stage enters the thermal desorption stage, the return pipe 133 is closed and the discharge pipe 135 is opened, so that the soil can be transported from the pretreatment device 1 to the thermal desorption device 2 to realize the transportation of the soil.

[0084] Reference Figure 2 and Figure 3 The thermal desorption device 2 includes a heating tank 21, a desorption tank 22 is arranged in the heating tank 21, the heating tank 21 and the desorption tank 22 are both arranged vertically, and the inner wall of the heating tank 21 and the outer wall of the desorption tank 22 are arranged at intervals, and the inner wall of the heating tank 21 is provided with a plurality of heating elements, and the heating elements are electric heating wires or flame nozzles or other devices capable of heating the soil to a desired temperature. The lower end of the feed pipe 135 in the soil turning mechanism 13 is connected to the side wall of the desorption tank 22, and the upper end of the heating tank 21 is provided with a polluted air pipe 221, and the polluted air pipe 221 is connected to the upper end of the desorption tank 22.

[0085] The desorption tank 22 can contain soil, and the soil can be heated by the setting of the heating element 211, thereby achieving thermal desorption of the soil, while the polluted gas pipe 221 can discharge the polluted gas separated by thermal desorption.

[0086] Reference Figure 4 A first stirring member 222 is also provided in the desorption tank 22. The first stirring member 222 is a spiral blade. The spiral blade is vertically arranged in the desorption tank 22. The upper end of the spiral blade is rotatably connected to the upper side wall of the desorption tank 22. The upper end of the spiral blade is coaxially connected to a driving motor. When the driving motor drives the spiral blade to rotate, the spiral blade can turn over the soil in the desorption tank 22, thereby improving the uniformity of heating of the soil.

[0087] Reference Figure 3 and Figure 4A first conveying mechanism 23 is also provided outside the heating tank 21. The first conveying mechanism 23 has the same structure as the soil turning mechanism 13. The feeding pipe 132 of the first conveying mechanism 23 is connected to the lower end of the heating tank 21, and the feeding pipe 135 of the first conveying mechanism 23 is connected to the cooling device 3. The first conveying mechanism 23 can realize the turning of the soil in the desorption tank 22 and can also transport the soil in the thermal desorption device 2 to the cooling device 3.

[0088] Reference Figure 3 and Figure 4 The cooling device 3 includes a cooling tank 31, which is arranged in the vertical direction. The feed pipe 135 of the first conveying mechanism 23 is connected to the side wall of the cooling tank 31. A second conveying mechanism 32 is arranged outside the cooling tank 31. The second conveying mechanism 32 has the same structure as the soil turning mechanism 13. The feed pipe 132 of the second conveying mechanism 32 is connected to the lower end of the cooling tank 31. The second conveying mechanism 32 can turn the soil in the cooling tank 31 and can also convey the cooled soil out of the cooling tank 31.

[0089] Reference Figure 3 and Figure 4 A water cooling tank 33 is sleeved on the outer side of the cooling tank 31, and the inner wall of the water cooling tank 33 is spaced apart from the inner wall of the cooling tank 31. A water inlet pipe 331 and a water outlet pipe 332 are provided on the water cooling tank 33, and both the water inlet pipe 331 and the water outlet pipe 332 are connected to the water cooling tank 33. Cooling water is introduced into the space between the water cooling tank 33 and the cooling tank 31 through the water inlet pipe 331, and is discharged from the water cooling tank 33 through the water outlet pipe 332 after the cooling water cools the soil.

[0090] Reference Figure 3 and Figure 4 A second stirring member 311 is provided in the cooling tank 31 , and the first stirring member 222 has the same structure as the second stirring member 311 , which can achieve uniform cooling of the soil in the cooling tank 31 .

[0091] Reference Figure 3 and Figure 4 The cooling tank 31 is also provided with a cooling air pipe 312 and a hot air pipe 313. One end of the cooling air pipe 312 is connected to the side wall of the cooling tank 31, and the other end of the cooling air pipe 312 is connected to an air supply member, which is an air compressor or an air tank. One end of the hot air pipe 313 is connected to the upper end of the cooling tank 31.

[0092] Cooling air is injected into the soil in the cooling tank 31 through the cooling air pipe 312, so that the cooling air and the soil exchange heat to achieve soil cooling, and the cooling air is converted into hot air and separated from the soil; the hot air carries the polluted gas remaining in the soil out of the soil; in addition, the cooling air contacts the organic matter in the soil, the organic matter produces a micro-combustion reaction, and the smoke generated by the micro-combustion reaction is carried out of the soil by the hot air. And the hot air carries the polluted gas and the smoke out of the cooling tank 31 through the hot air pipe 313.

[0093] Reference Figure 2 and Figure 3 The soil remediation equipment also includes a heat exchanger 5, and the polluted gas pipe 221, the hot air pipe 313 and the water outlet pipe 332 are all connected to the heat exchanger 5, wherein the polluted gas, hot air and cooling water exchange heat in the heat exchanger 5, and the polluted gas, hot air and cooling water flow relatively independently, then the heat exchanger 5 can adjust the temperature of the polluted gas, hot air and cooling water to the same or similar.

[0094] Reference Figure 2 and Figure 5 The heat exchanger 5 is connected to the preheating mechanism 14. Specifically, the water inlet ends of the third first spiral tube 141 and the three second spiral tubes 142 are all connected to the heat exchanger 5. Therefore, the polluted gas, hot air and cooling water are all sent to the corresponding first spiral tube 141 and second spiral tube 142, which can realize the preheating of the soil in the pretreatment device 1.

[0095] Reference Figure 2 and Figure 5 The outlet ends of the first spiral tube 141 and the second spiral tube 142 into which the cooling water is introduced are connected to the water inlet pipe 331. Therefore, the cooling water after the expected heating will flow back to the cooling device 3, thereby achieving the cooling of the soil. Such an arrangement can achieve the recycling of cooling water.

[0096] Reference Figure 2 The soil remediation equipment further includes a storage device, which includes a first storage tank 61, a second storage tank 62 and a third storage tank 63. The first storage tank 61 is connected to the first gas outlet pipe 112, the second storage tank 62 is connected to the polluted gas pipe 221, and the third storage tank 63 is connected to the hot air pipe 313. The storage device is configured to store various gases generated.

[0097] The implementation principle of the embodiment of the present application is: after the soil is sent to the pretreatment equipment 1, the soil will pass through the pretreatment equipment 1, the thermal desorption equipment 2 and the cooling equipment 3 in sequence. During this process, chemical remediation reagents will be added to the soil, and then the soil will be stirred and preheated, thermally desorbed and cooled in sequence, thereby realizing the separation of pollutants in the soil and realizing the soil remediation function.

[0098] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A soil remediation process based on ex situ chemical heating thermal desorption method, characterized in that: The following steps are involved: The first step is to add chemical remediation agents to the soil; The second step is pretreatment, where the soil with chemical remediation agents is stirred and preheated; The third step is thermal desorption, where the preheated soil is heated for desorption, the pollutants in the soil are vaporized to produce polluted gas, and the polluted gas is separated from the soil; The fourth step is air cooling, in which cooling air is introduced into the soil after thermal desorption to cool the soil. After the cooling air cools the soil, hot air is generated, and the hot air is separated from the soil.

2. A soil remediation process based on ex situ chemical heating thermal desorption method according to claim 1, characterized in that: The following steps are also included: In the fifth step, the polluted gas separated in the third step is mixed with the hot air separated in the fourth step, and the mixed gas is used for preheating the soil in the second step.

3. The soil remediation process based on ex situ chemical heating thermal desorption method according to claim 1 is characterized in that: The following steps are also included: In the fifth step, the polluted gas separated in the third step is heat exchanged with the hot air separated in the fourth step, and the temperatures of the polluted gas and the hot air are adjusted to be the same. The polluted gas and the hot air after the heat exchange are independently used for preheating the soil in the second step.

4. A soil remediation process based on ex situ chemical heating thermal desorption method according to claim 3, characterized in that: The fourth step also includes the following steps: cooling water cooling, cooling the soil by heat exchange with cooling water.

5. A soil remediation process based on ex situ chemical heating thermal desorption method according to claim 4, characterized in that: The fifth step also includes the following steps: exchanging heat between the cooling water after cooling the soil and the polluted gas separated in the third step and the hot air separated in the fourth step, adjusting the temperatures of the cooling water, the polluted gas and the hot air to the same, and independently using the cooling water, the polluted gas and the hot air after the heat exchange for preheating the soil in the second step.

6. A soil remediation process based on ex situ chemical heating thermal desorption method according to claim 5, characterized in that: The fifth step also includes the following steps: after the cooling water preheats the soil in the second step, it flows back to the fourth step for heat exchange cooling of the soil.

7. A soil remediation device based on ex situ chemical heating thermal desorption method, characterized in that: include: A reagent adding device (4), a pretreatment device (1), a thermal desorption device (2) and a cooling device (3), wherein the pretreatment device (1), the thermal desorption device (2) and the cooling device (3) are connected in sequence, and the reagent adding device (4) is connected to the pretreatment device (1); It also includes a heat exchanger (5), and the pretreatment device (1), the thermal desorption device (2) and the cooling device (3) are all connected to the heat exchanger (5); It also includes a storage device (6), wherein the storage device (6) is connected to the pretreatment device (1).

8. The soil remediation equipment based on ex situ chemical heating thermal desorption method according to claim 7 is characterized in that: The pretreatment equipment (1) comprises a mixing tank (11) and a soil turning mechanism (13); the mixing tank (11) is arranged in a vertical direction, and a feed port (111) is provided on a side wall of the mixing tank (11); the reagent adding device (4) is connected to the mixing tank (11); and a stirring mechanism (12) for stirring the soil is provided in the mixing tank (11); The soil turning mechanism (13) comprises a conveying pipe (131), the conveying pipe (131) being vertically arranged outside the mixing tank (11), a feeding pipe (132) being arranged at the lower end of the conveying pipe (131), and a return pipe (133) being arranged at the upper end of the conveying pipe (131), the feeding pipe (132) and the return pipe (133) being arranged obliquely in the vertical direction; The upper end of the feed pipe (132) is in communication with the bottom of the mixing tank (11), and the lower end of the feed pipe (132) is in communication with the mixing tank (11); The upper end of the return pipe (133) is in communication with the delivery pipe (131), and the lower end of the return pipe (133) is in communication with the mixing tank (11); A vertical feeder (134) for conveying soil in a vertical direction is arranged in the conveying pipe (131).

9. The soil remediation equipment based on ex situ chemical heating thermal desorption method according to claim 8 is characterized in that: A discharge pipe (135) is also provided at the upper end of the delivery pipe (131). The discharge pipe (135) is arranged obliquely in the vertical direction. The upper end of the discharge pipe (135) is connected to the delivery pipe (131), and the lower end of the discharge pipe (135) is connected to the thermal desorption device (2). A sealing component (136) for closing or opening the discharge pipe (135) is provided in the discharge pipe (135).

10. The soil remediation equipment based on ex situ chemical heating thermal desorption method according to claim 8, characterized in that: The stirring mechanism (12) comprises a stirring main pipe (121) and a plurality of stirring plates (123); the stirring main pipe (121) is vertically arranged in the mixing tank (11); the upper end of the stirring main pipe (121) is rotatably connected to the mixing tank (11); and a stirring driving member (122) for driving the stirring main pipe (121) to rotate is arranged on the stirring main pipe (121); The stirring plate (123) is arranged in a vertical direction, and a plurality of the stirring plates (123) are arranged in sequence and spaced apart along the circumference of the stirring main pipe (121), and the stirring plate (123) is connected to the outer wall of the stirring main pipe (121), a medicine cavity (1231) is provided in the stirring plate (123), a plurality of nozzles (1232) are arranged outside the stirring plate (123), and the nozzles (1232) and the stirring main pipe (121) are both in communication with the medicine cavity (1231); The stirring main pipe (121) is in communication with the drug adding device (4).

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