In-situ thermal conduction type pollution soil layering differential gas heating method and application thereof

Abstract

The application discloses an in-situ heat conduction type contaminated soil layering differential gas heating method and application thereof, which comprises the following steps: 1) determining the plot characteristics of a region to be heated; 2) extending the plot to be heated vertically and generalizing layering; 3) determining the heating target temperature of each layer of soil; 4) determining the heating period; 5) determining the heating influence range of a single heating device in the temperature rising section; 6) calculating the power input of a single heating device in each layer of soil unit depth; 7) arranging longitudinal in-situ heating devices in the region to be heated in the contaminated soil, and determining the number of turns of the spiral of the spiral flue gas inner tube in each layer of soil depth according to the power input of a single heating device in each layer of soil unit depth; and 8) heating. The application can flexibly and pertinently realize the differential heating requirements of different depth soil layers, realizes accurate heating, and saves energy.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of contaminated soil and groundwater remediation, and particularly relates to an in-situ thermal conduction type contaminated soil layering differential gas heating method and application thereof. BACKGROUND

[0002] For soil contaminated by organic pollutants, especially soil contaminated by polycyclic aromatic hydrocarbons, pesticides, petroleum hydrocarbons and other pollutants that are difficult to handle by traditional remediation processes, in-situ thermal desorption technology is widely used in in-situ treatment technology due to its good treatment effect, strong site adaptability and other advantages. At present, the mainstream in-situ thermal desorption technologies on the market include in-situ resistance heating, in-situ thermal conduction-electric heating, in-situ thermal conduction-gas heating and in-situ steam heating.

[0003] Among them, in-situ resistance heating and in-situ steam heating are limited by factors such as soil moisture content, electrical conductivity, soil homogeneity and soil permeability, and are less applicable to site types, and have a low application proportion. In-situ thermal conduction heating is the mainstream technology for in-situ heating at the present stage.

[0004] In-situ thermal conduction heating is to build a heating well in the soil, heat the casing of the heating well by arranging an electric heating rod or passing in the flue gas after combustion in the heating well, and continuously deliver heat to the surrounding soil through heat radiation of the heated casing, so as to heat the surrounding soil. According to the different energy supply situations, it can be divided into in-situ thermal conduction-electric heating and in-situ thermal conduction-gas heating. The in-situ conduction heating method is less affected by the physical and chemical properties of the soil, and has wider adaptability. However, due to the arrangement of the flue gas heating passage in the heating well, there are some problems in the in-situ thermal conduction heating:

[0005] The heating well used in the in-situ thermal conduction-gas heating process is composed of inner and outer casings, the flue gas after combustion is input from the inner casing and is led out from the interlayer of the inner and outer casings by a blower, and the heating of the inner and outer casings by the flue gas realizes the heating of the surrounding soil. In the current process, the inner and outer casings are vertically and parallelly arranged, which causes the flow path of the flue gas in the casing to be limited only by the depth of the heating well or the length of the inner casing. If the heating power needs to be improved, only the heat quantity and the gas temperature can be increased, which results in low heat utilization rate of the flue gas after combustion and increased cost. In addition, the path of the flue gas passing through the inner and outer casings is basically the same along the vertical direction of the heating well, and it is also impossible to realize the differential heating requirement of different depth soil layers. SUMMARY

[0006] The purpose of the present application is to provide an in-situ thermal conduction type contaminated soil layering differential gas heating method based on the above problems, which can flexibly and specifically realize the differential heating requirement of different depth soil layers, realize accurate heating and save energy. The purpose of the present application is realized by the following technical scheme:

[0007] An in-situ thermal conduction type contaminated soil layering differential gas heating method, comprising the following steps:

[0008] Step one: determine the plot characteristics of the area to be heated: the plot characteristics include plot pollution characteristics, soil layer soil characteristics and hydrogeological characteristics;

[0009] Step two: according to the plot characteristics, the plot to be heated is vertically generalized;

[0010] Step three: according to the characteristics of each layer of the plot, determine the heating target temperature of each layer of soil;

[0011] Step four: according to the overall construction period requirement, and comprehensively considering the plot characteristics of each layer, determine the heating period, the heating period includes the heating time, the constant temperature time and the cooling time;

[0012] Step five: according to the stratum soil characteristics of each layer of soil, determine the heating influence range of a single heating device in the heating section;

[0013] Step six: according to the results determined in steps two to five, calculate the power input of a single heating device in each layer of soil unit depth;

[0014] Step seven: set up longitudinal in-situ heating devices in the contaminated soil area to be heated, the in-situ heating device includes a heating well, a burner and a burner nozzle arranged above the heating well, and a spiral flue gas inner pipe arranged in the heating well, the spiral flue gas inner pipe is composed of a plurality of spirals arranged longitudinally, the upper and lower ports of the spiral flue gas inner pipe are respectively connected with a combustion flue gas inner pipe and a combustion flue gas outer exhaust pipe, and the combustion flue gas inner pipe is connected with the burner nozzle; according to the power input of a single heating device in each layer of soil unit depth determined in step six, determine the number of spirals in each layer of soil depth of the spiral flue gas inner pipe;

[0015] Step eight: use the heating device of step seven, heat according to the power determined in step six and the heating period determined in step four.

[0016] In step one, the plot pollution characteristics include the type of pollutants, the saturated vapor pressure of pollutants, the boiling point of pollutants, the spatial distribution range of pollutants and the concentration of pollutants; the stratum soil characteristics include soil category, soil water content, soil particle density, soil porosity, soil particle heat capacity, soil initial temperature, soil air permeability, soil thermal conductivity and soil temperature coefficient; the hydrogeological characteristics include groundwater depth, aquifer thickness, hydraulic gradient, soil permeability coefficient and groundwater flow rate.

[0017] Further optimization, in step six, when setting the final temperature T cWhen the temperature is greater than 100℃, the power input of each layer of soil per unit depth is calculated by formula (1):

[0018]

[0019] In the formula, β represents the average power input per unit depth of a single heating device, W·m -1 ; t b represents the time required for water in the soil to completely vaporize, day; t c2 represents the time required for the soil to be heated from 100℃ to the target temperature, day; A represents the range of influence of the thermal radiation of a single heating device, m 2 ; p s represents the density of soil particles, g·m -3 ; C s represents the heat capacity of soil particles, W·day·g -1 ·℃ -1 ; θ represents the porosity of the soil; p w represents the density of water, g·m -3 ; C w represents the heat capacity of water, W·day·g -1 ·℃ -1 ; δ represents the saturation of water in the soil; T b represents the boiling point of water, ℃; T a represents the temperature of the soil before heating, ℃; T c represents the final temperature of the soil, ℃; h w represents the heat of vaporization of water, with the unit being W·day·g –1 .

[0020] In step six, when the final temperature T c of the soil heating is less than or equal to 100℃, the power input of each layer of soil per unit depth is calculated by formula (2):

[0021]

[0022] In the formula, σ is a value between 0 and 1, representing the proportion of water evaporation under the condition that the heating temperature is less than 100℃, t c1 represents the time required for the soil to be heated to the target temperature, day.

[0023] Further, the method for determining the number of spirals in step seven is shown in formula (3) and formula (4):

[0024]

[0025] N = V i / V0 (4)

[0026] In the formula, hi m is the depth of the i-th layer, m; β i W is the power input in the unit depth of the i-th layer of soil, W·m -1 ; ρ y ρ is the density of the flue gas after combustion, g / m 3 ;

[0027] T1 is the temperature at the outlet of the burner, ℃;

[0028] T2 is the temperature of the flue gas after passing through the i-th layer of soil; ℃;

[0029] T0 is the initial temperature before the gas and air mixture is combusted, ℃;

[0030] Cp is the average specific heat of the flue gas temperature from T0 to T1, j / g·℃;

[0031] Cp is the average specific heat of the flue gas temperature from T0 to T2, j / g·℃;

[0032] V i is the volume of flue gas required to heat the soil per unit time h i depth of soil, m 3 ;

[0033] V0 is the volume of a single spiral inner tube, m 3 ;

[0034] N is the number of spirals of the i-th layer of soil heating device spiral flue gas inner tube.

[0035] Further optimization, in step six, the in-situ heating device further comprises a gas supply device, a flue gas centralized discharge device and a temperature control system, the gas supply device is connected with the burner through a gas supply pipeline; the flue gas centralized discharge device is connected with the flue gas exhaust pipe through the flue gas discharge pipeline; the temperature control system is connected with the temperature sensor arranged in the contaminated soil at different depths, the temperature control system receives the signal of the temperature sensor and sends the signal to the gas supply device to control the output of the gas.

[0036] The heating method described in the application is applied to the auxiliary heating of organic contaminated soil pollutant extraction.

[0037] Further, the required heat of the contaminated soil in the vertical different horizontal layers is different.

[0038] The advantages and beneficial effects of the application are:

[0039] The present application can adopt targeted and different heating schemes according to different pollutant types, spatial distribution, soil, and hydrogeological conditions in contaminated soil remediation, realize different heating temperature at different depths, and is beneficial to precise depth heating, can effectively save energy and reduce carbon emissions under the premise of ensuring heating effect.

[0040] The present application adjusts the pitch of the spiral in the longitudinal direction to change the heating power of the heating device per unit depth, so as to better adapt to the different heating needs at different depths.

[0041] The present application detects the heating temperature of different strata soil by burying temperature sensors of different depths in the soil around the heating well, realizes precise heating with fixed depth and power, greatly improves the precision of heating temperature at different depths and different strata, and improves the efficiency of construction. BRIEF DESCRIPTION OF DRAWINGS

[0042] The present application will be further described below in combination with the drawings and examples.

[0043] Figure 1 It is the operation flowchart in Example 1.

[0044] Figure 2 It is the structure schematic diagram of the heating device in Example 1.

[0045] Figure 3 It is the specific application scene schematic diagram of the heating method in Example 2.

[0046] Figure 4 It is the heating cycle schematic diagram.

[0047] Figure 5 It is the structure schematic diagram of the in-situ heating device in Example 3.

[0048] Figure 6 It is the structure schematic diagram of the in-situ heating device in Example 4.

[0049] 11, burner; 12, burner nozzle; 13, spiral flue gas inner pipe; 141, combustion flue gas inner guide pipe; 142, combustion flue gas outer exhaust pipe; 143, pipeline connector; 15, heating well outer sleeve pipe; 16, heating well flange cover piece; 21, in-situ multi-phase extraction well; 22, open screen section; 23, solid pipe section; 24, multi-phase extraction well wellhead; 25, liquid phase extraction pipeline; 26, submersible pump; 31, gas supply device; 32, flue gas centralized exhaust device; 33, temperature control system; 341, gas supply pipeline; 342, flue gas exhaust pipeline; 35, temperature sensor; 36, thermocouple; 37, temperature sensor lead wire; 38, thermocouple connected to the spiral flue gas inner pipe; 4, tail water and tail gas treatment system; 51, horizontal barrier layer; 52, vertical barrier wall. S-1, upper layer; S-2, middle layer; S-3, lower layer. RD represents the heating section. DETAILED DESCRIPTION

[0050] Example 1

[0051] A method for in-situ thermal conductive contaminated soil layering differentiation gas heating, as shown in FIG. 1, comprises the following steps: Figure 1

[0052] Step one: determine the plot characteristics of the area to be heated: the plot characteristics include plot pollution characteristics, soil layer soil characteristics, and hydrogeological characteristics; the plot pollution characteristics include the type of pollutants, the saturated vapor pressure of pollutants, the boiling point of pollutants, the spatial distribution range of pollutants, and the concentration of pollutants; the soil layer soil characteristics include soil category, soil water content, soil particle density, soil porosity, soil particle heat capacity, soil initial temperature, soil permeability, soil thermal conductivity, and soil temperature coefficient; the hydrogeological characteristics include groundwater depth, aquifer thickness, hydraulic gradient, soil permeability coefficient, and groundwater flow rate. In this embodiment, the vertical distribution of pollutants is uniform, and the pollutants are petroleum hydrocarbons, PAHs with part of the boiling point below 250°C, semi-volatile, and the upper and lower layers of soil have little difference in properties, and the central soil has poor thermal conductivity.

[0053] Step two: generalize the vertical layering of the plot to be heated according to the plot characteristics; this embodiment is divided into three layers.

[0054] Step three: determine the heating target temperature of each layer of soil according to the plot characteristics of each layer; the heating interval is 120-220°C according to the properties of the type of pollutants, and the heating target temperatures of the upper layer, the middle layer, and the lower layer are determined to be 125°C, 200°C, and 150°C, respectively, according to the soil layer and hydrogeological characteristics.

[0055] Step four: determine the heating period according to the overall project duration requirement and taking into account the plot characteristics of each layer, the heating period includes the warming-up time, the constant temperature time, and the cooling-down time.

[0056] Step five: calculate the heating influence range A of a single heating device in the warming-up section according to the soil layer characteristics (temperature coefficient) of each layer of soil.

[0057] Step six: calculate the power input of a single heating device in each layer of soil per unit depth according to the results determined in steps two to five.

[0058] Because the target temperature is higher than 100°C, formula (1) is used to calculate the power input per unit depth of each layer of soil.

[0059] ​Step seven: set longitudinal in-situ heating devices in the contaminated soil area to be heated, the in-situ heating device comprises a heating well, a burner 11 and a burner nozzle 12 arranged above the heating well, and a spiral flue gas inner tube 13 arranged in the heating well, the spiral flue gas inner tube 13 is composed of a plurality of spirals arranged longitudinally, the upper and lower ports of the spiral flue gas inner tube 13 are respectively connected with a combustion flue gas inner pipe 141 and a combustion flue gas outer exhaust pipe 142, the combustion flue gas inner pipe 141 is connected with the burner nozzle 12; the number of turns and the spacing of the spirals of the spiral flue gas inner tube 13 in each layer of soil are determined according to the power input of each heating device in the unit depth of each layer of soil determined in step six; and the calculation is performed according to formula (3) and formula (4).

[0060] Step eight: using the heating device of step seven, heating is performed according to the heating power determined in step six and the heating period determined in step four.

[0061] Example 2

[0062] An in-situ heat conduction type contaminated soil layered differential gas heating method, comprising the following steps:

[0063] Step one: determine the plot characteristics of the area to be heated: the plot characteristics include plot pollution characteristics, soil layer soil characteristics, and hydrogeological characteristics; the plot pollution characteristics include the types of pollutants, the saturated vapor pressure of pollutants, the boiling point of pollutants, the spatial distribution range of pollutants, and the concentration of pollutants; the soil layer soil characteristics include soil category, soil water content, soil particle density, soil porosity, soil particle heat capacity, soil initial temperature, soil air permeability, soil thermal conductivity, and soil temperature conductivity coefficient; the hydrogeological characteristics include groundwater depth, aquifer thickness, hydraulic gradient, soil permeability coefficient, and groundwater flow rate. In this embodiment, the vertical distribution of pollutants is divided into three parts: the upper layer is mainly benzene series, chlorinated hydrocarbons and other VOCs, which are easy to volatilize; the middle layer is mainly petroleum hydrocarbons and part of PAHs with boiling points below 250℃, which are semi-volatile; the lower layer is mainly pesticides with boiling points above 250℃, which are relatively difficult to volatilize; the soil properties are uniformly distributed vertically. The properties of the pollutants are shown in Table 1:

[0064] Table 1

[0065] No. Contaminant category Volatile characteristic Heating zone 1 Benzene series, chlorinated hydrocarbons, etc. VOCs Easily volatile 60-120℃ 2 Petroleum hydrocarbons, PAHs with part of boiling point below 250°C Semi-volatile 120-220℃ 3 PAHs with boiling point above 250°C, PCBs, pesticides Less volatile 220-350℃

[0066] Step two: generalize and layer the plot to be heated vertically according to the plot characteristics; this embodiment is divided into three layers.

[0067] Step three: determine the heating target temperature of each layer of soil according to the plot characteristics of each layer; the heating target temperatures of the upper layer, the middle layer and the lower layer are respectively determined as 90℃, 150℃ and 300℃.

[0068] Step four: according to the overall construction period requirements, and taking into account the characteristics of each layer of land, determine the heating cycle, which contains the heating time, constant temperature time and cooling time.

[0069] Step five: according to the stratum soil characteristics (temperature coefficient) of each layer of soil, calculate the heating influence range A of a single heating device in the heating section.

[0070] Step six: according to the results determined in steps two to five, calculate the power input of a single heating device in each layer of soil per unit depth.

[0071] Because the target temperature of the middle and lower layers is higher than 100℃, the power input per unit depth of soil is calculated by formula (1); while the target temperature of the upper layer is lower than 100℃, the power input per unit depth of soil is calculated by formula (2); the heating cycle is shown in Figure 4 .

[0072] Step seven: set up longitudinal in-situ heating devices in the contaminated soil area to be heated, as shown in Figure 3 , the in-situ heating device includes a heating well, a burner 11 and a burner nozzle 12 arranged above the heating well, and a spiral flue gas inner tube 13 arranged in the heating well, which is composed of a plurality of spirals arranged longitudinally, the upper and lower ports of the spiral flue gas inner tube 13 are respectively connected with a combustion flue gas inner duct 141 and a combustion flue gas outer exhaust pipe 142, and the combustion flue gas inner duct 141 is connected with the burner nozzle 12; according to the power input of a single heating device per unit depth of soil in each layer of soil determined in step six, the number of turns and the pitch of the spiral flue gas inner tube 13 in each layer of soil are determined, which are calculated according to formula (3) and formula (4).

[0073] The in-situ heating device also includes a gas supply device 31, a flue gas concentration discharge device 32 and a temperature control system 33, the gas supply device 31 is connected with the burner 11 through a gas supply pipeline 341, the flue gas concentration discharge device 32 is connected with the flue gas outer exhaust pipe 142 through the flue gas discharge pipeline 342; the temperature control system 33 is connected with the temperature sensor 35 arranged in the contaminated soil at different depths, the temperature control system 33 receives the signal of the temperature sensor 35 and sends a signal to the gas supply device 31 to control the output of the gas. The connection points of each layer of the spiral flue gas inner tube 13 are provided with temperature sensors (the thermocouple 38 connected on the spiral flue gas inner tube is part of the temperature sensor) connected with the temperature control system 33.

[0074] Step eight: use the heating device of step seven, according to the heating power determined in step six and the heating cycle determined in step four to heat.

[0075] The embodiment is applied to auxiliary heating of organic contaminated soil pollutant extraction, and required heat of different vertical layers in the contaminated soil is different, and specific use states are as shown in Figure 3 A horizontal barrier layer 51 and a vertical barrier wall 52 are arranged at an edge of an in-situ heating area, an in-situ heating device is arranged in a middle part of the in-situ heating area, the in-situ heating device is arranged in a triangular or hexagonal shape, and an in-situ multi-phase extraction device (including an in-situ multi-phase extraction well 21, an open screen section 22, a solid pipe section 23, a multi-phase extraction well head 24, a liquid phase extraction pipeline 25, and a submersible pump 26) is arranged in a middle part of the in-situ heating device, and the in-situ multi-phase extraction device is connected to a tail water and tail gas treatment device 4.

[0076] Embodiment 3

[0077] An in-situ heat conduction type contaminated soil layering differential gas heating method has the same operation steps as those of embodiment 1, only because the target temperature determined in step three is different, the power input in a unit depth of each layer of soil determined in step six is different, and the spiral distribution of the heating device in step seven is different, as shown in Figure 5 The uppermost section is provided with 0 spirals, and is a non-heating area.

[0078] Embodiment 4

[0079] An in-situ heat conduction type contaminated soil layering differential gas heating method has the same operation steps as those of embodiment 1, only because the target temperature determined in step three is different, the power input in a unit depth of each layer of soil determined in step six is different, and the spiral distribution of the heating device in step seven is different, as shown in Figure 6 The middle section is provided with 0 spirals, and is a non-heating area.

[0080] Finally, it should be noted that the above merely serves to illustrate the technical solutions of the present application and not to limit, and although the present application has been described in detail with reference to the preferred arrangement, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for in-situ thermal conductive contaminated soil layering and differential gas heating, characterized in that: The method comprises the following steps: Step one: determining the plot characteristics of the region to be heated: the plot characteristics include plot pollution characteristics, soil layer soil characteristics, and hydrogeological characteristics; Step two: according to the plot characteristics, the region to be heated is vertically generalized and layered; Step three: according to the plot characteristics of each layer, the heating target temperature of each layer of soil is determined; Step four: according to the overall construction period requirement, and comprehensively considering the plot characteristics of each layer, the heating period is determined, which includes the heating-up time, the constant-temperature time, and the cooling-down time; Step five: according to the soil layer soil characteristics of each layer of soil, the heating influence range of a single heating device in the heating-up section is determined; Step six: according to the results determined in steps two to five, the power input of a single heating device in each layer of soil unit depth is calculated; When setting the final temperature T of soil heating c For a temperature greater than 100°C, the power input in the unit depth of each layer of soil is calculated using equation (1): where: β represents the average power input per unit depth of the individual heating device, W-m -1 ; t b represents the time required for complete vaporization of water in the soil, day; t c2 represents the time required for heating the soil from 100°C to the target temperature, day; A represents the range of influence of the thermal radiation of the individual heating device, m 2 ; p s represents the density of the soil particles, g-m -3 ; C s represents the heat capacity of the soil particles, W-day-g -1 ·°C -1 ; θ represents the porosity of the soil; p w represents the density of water, g-m -3 ; C w represents the heat capacity of water, W-day-g -1 ·°C -1 ; δ represents the degree of saturation of the soil with water; T b represents the boiling point of water, °C; T a represents the temperature of the soil before heating, °C; T c represents the final temperature of the soil, °C; h w represents the heat of vaporization of water, in W-day-g –1 ; When the final temperature T of the soil heating is set c When the final temperature T of the soil heating is set c When the final temperature T of the soil heating is set c When the final temperature T of the soil heating is set c When the final temperature T of the soil heating is set c When the final temperature T of the soil heating is set < In the formula, σ is a number from 0 to 1, representing the proportion of water evaporation under the condition that the heating temperature is lower than 100°C, t c1 represents the time required for soil heating to a target temperature, day; Step seven: a longitudinal in-situ heating device is arranged in the region to be heated in the contaminated soil, the in-situ heating device comprises a heating well, a burner and a burner nozzle arranged above the heating well, and a spiral flue gas inner pipe arranged in the heating well, the spiral flue gas inner pipe is composed of a plurality of spirals arranged longitudinally, the upper and lower ports of the spiral flue gas inner pipe are respectively connected with a combustion flue gas inner conduit and a combustion flue gas outer exhaust pipe, the combustion flue gas inner conduit is connected with the burner nozzle; the number of spirals of the spiral flue gas inner pipe in each layer of soil depth is determined according to the power input of a single heating device in each layer of soil unit depth determined in step six; the determination method of the number of spirals is shown in formula (3) and formula (4): N = V i / V0 (4) wherein: h i is the depth of the i-th layer, m; β i W / m2 -1 ; p y p is the density of the flue gas after combustion, g / m 3 ; T1 is the burner outlet temperature, °C; T2 is the temperature of flue gas after passing through the i-th layer of soil; ℃; T0 is the initial temperature before the mixed combustion of fuel gas and air; ℃; Cp, average specific heat for the flue gas temperature change from T0 to T1, j / g-°C; Cp is the average specific heat of the flue gas during the change from T0 to T2, j / g-°C; V i For a unit of time h i Volume of flue gas required for deep soil heating, m 3 ; V0 is the volume of the single inner spiral tube, m 3 ; N is the number of spirals of the spiral flue gas inner pipe of the i-th layer of soil heating device; Step eight: the heating device of step seven is used to heat according to the power determined in step six and the heating period determined in step four.

2. The in-situ thermal conductive contaminated soil layering differential gas heating method according to claim 1, characterized in that: In step one, the plot pollution characteristics include the types of pollutants, the saturated vapor pressure of pollutants, the boiling point of pollutants, the spatial distribution range of pollutants, and the concentration of pollutants; the soil layer soil characteristics include the soil category, the soil water content, the soil particle density, the soil porosity, the heat capacity of soil particles, the initial temperature of soil, the soil permeability, the soil thermal conductivity, and the soil temperature coefficient; the hydrogeological characteristics include the groundwater depth, the aquifer thickness, the hydraulic gradient, the soil permeability coefficient, and the groundwater flow rate.

3. The in-situ thermal conductive soil pollution stratification differentiated gas heating method according to claim 1, characterized in that: In step seven, the in-situ heating device further comprises a fuel gas supply device, a flue gas centralized discharge device, and a temperature control system, the fuel gas supply device is connected with the burner through a fuel gas supply pipeline; the flue gas centralized discharge device is connected with the flue gas exhaust pipe through a flue gas discharge pipeline; the temperature control system is connected with temperature sensors arranged in the contaminated soil at different depths, receives signals from the temperature sensors, and sends signals to the fuel gas supply device to control the output of fuel gas.

4. Use of the heating method according to claim 1, characterized in that: The application is applied to the auxiliary heating of organic contaminated soil pollutant extraction.

5. Use of the heating method according to claim 4, characterized in that: The required heat is different in different vertical layers of the contaminated soil.

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