A control method for oil sludge heap smoldering disposal

Abstract

The application discloses a control method of oil sludge pile type smoldering disposal, controls a smoldering process of a smoldering self-maintenance disposal system, determines a control stage and a control parameter of the smoldering process after fuel parameters are acquired, controls in a smoldering ignition stage so that the fuel can be quickly ignited and enters the smoldering stage faster, controls in a smoldering self-maintenance stage so that the smoldering process is in a highest combustion efficiency or a most economical working condition, or corresponding parameters are selected according to specific working conditions to consider the efficiency and the cost, and the treatment effect of the smoldering process of the oil sludge is ensured.

Description

Technical Field

[0001] This invention relates to the field of oil smoldering control technology, and specifically to a control method for oil smoldering disposal in a pile. Background Technology

[0002] Oily sludge, a typical byproduct of the petroleum industry, has attracted significant attention in environmental engineering due to its complex composition and difficult treatment. Common oily sludge treatment technologies include physical separation, thermal conversion, biological treatment, solidification and landfill, solvent extraction, and incineration. However, all these technologies have their own limitations. The smoldering method for treating oily sludge offers several advantages: firstly, it demonstrates significant energy self-sufficiency, reducing dependence on external heat sources through energy transfer and conversion during combustion wave propagation; secondly, it improves pollutant control, as the unique gas-solid mass transfer conditions in the combustion zone effectively suppress harmful gases easily generated during conventional incineration; and thirdly, it improves the environmental compatibility of the treated residue, showing greater stability in key indicators such as leaching toxicity. Therefore, the use of smoldering technology for oily sludge treatment is gradually being adopted. However, existing smoldering technologies still suffer from low fuel efficiency, long combustion times, and high costs. This invention provides a control method for smoldering oily sludge pile disposal to address these problems. Summary of the Invention

[0003] This invention provides a control method for the smoldering disposal of oil sludge piles, which controls the smoldering process to keep it under the most suitable operating conditions.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] A method for controlling smoldering in oil sludge piles includes the following steps:

[0006] S1, Fuel Mixing: Mix oil sludge and quartz sand according to a set ratio to form fuel;

[0007] S2, Parameter Acquisition: Acquire various parameters of the fuel and determine the control parameters of the smoldering process based on the fuel parameters;

[0008] S3, Preparation before ignition: Place the mixed fuel in the smoldering chamber to form a fuel pile, and set a temperature measuring point in the fuel pile;

[0009] S4, Ignition and Combustion: The bottom of the fuel pile is heated in a gradient to ignite it, and the temperature change of the fuel pile is monitored in real time. Once the bottom of the fuel pile is ignited, gas is supplied from the bottom of the fuel pile to keep it burning.

[0010] S5, Smoldering Self-Sustaining: After successful ignition, ignition is stopped and smoldering enters self-sustaining mode. At the same time, the gas supply is adjusted to control smoldering, so that combustion is always at the highest combustion efficiency to achieve the shortest combustion time, or the most economical gas supply is adopted to achieve the lowest cost.

[0011] S6, End of Smoldering: After the smoldering ends through real-time temperature monitoring, gas supply is stopped. After the fuel pile has completely cooled and extinguished, the waste from the combustion is cleaned up, completing one smoldering process.

[0012] In step S2, various parameters of the fuel are collected and tested, and the ignition layer thickness, make-up air point, and make-up air speed are determined based on the fuel parameters.

[0013] Furthermore, the ignition layer thickness is the ignition thickness achieved in step S4 when the bottom of the fuel pile is ignited by gradient heating with fuel gas, and is determined by the following formula:

[0014] ,

[0015] The thickness of the ignition layer is ,

[0016] In the formula,

[0017] x0: Smoldering front position, i.e., the position of the exothermic front or the position where the material just reaches the ignition point. Its value is the minimum smoldering thickness, in meters.

[0018] x S Location of the hot spot in the combustion zone, or the location of the peak smoldering temperature, in meters (m).

[0019] q v ，， Heat release rate per unit volume of material, kJ / (m³) 3 ·s);

[0020] ρ m Material density, kg / m³ 3 ;

[0021] C m Specific heat capacity of the material, kJ / (kg·℃);

[0022] U s : Smoldering peak propagation speed, m / s;

[0023] T0: Ignition temperature, also known as flash point temperature, is the temperature at the smoldering front when the flame is turned off, in °C.

[0024] T S Peak smoldering temperature, °C;

[0025] q ， : Conductive heat flux density at x0, kJ / (m2 ·s).

[0026] Furthermore, when x is measured S Once the temperature at the point reaches the ignition point To, it is considered that the bottom of the fuel pile is ignited. The moment when air is introduced into the smoldering body for makeup air is called the makeup air point. The makeup air rate at the makeup air point is determined by the following formula:

[0027] ,

[0028] The air supply point should be selected slightly below U. max The make-up air velocity is used for make-up air supply, and U in the formula s Take U smax Perform calculations.

[0029] In the formula,

[0030] U max Air velocity U when air is introduced g The maximum value, m / s;

[0031] U g : Air velocity when air is introduced, m / s;

[0032] ρ g Air density, kg / m³ 3 ;

[0033] c g Specific heat capacity of air, kJ / (kg·℃);

[0034] Y O2 The mass fraction of oxygen in the air, dimensionless, and this value is a constant;

[0035] Q O Heat (kJ) released per unit (kg) of oxygen consumed;

[0036] The proportion of air in the voids of a smoldering body, dimensionless;

[0037] U0: The total theoretical air velocity required for the complete smoldering oxidation of major elements such as C, H, N, and S under a given mass of oil sludge material, in m / s.

[0038] Furthermore, in step S5, when the temperature at x0 reaches the ignition point To as measured in real time, a smoldering front is formed in the fuel pile, and ignition is successful. Then, ignition is stopped.

[0039] Furthermore, in step S5, the shortest combustion time is achieved when combustion is consistently at its highest efficiency, meaning the fuel maintains its maximum smoldering rate U. smaxCombustion can achieve the shortest combustion time. To ensure that combustion remains at its highest efficiency, the airflow velocity U needs to be controlled. g To take control;

[0040] Inlet air velocity , when U min <U g When U < U0, U s With U g Increases as U increases; when U0≤U g <U max At that time, U s With U g Increase and decrease; when U g When U = 0, the smoldering body has the maximum exothermic heat flux q. ， At this point, the maximum smoldering velocity U is reached. smax ;

[0041] U min 、U0、U smax The calculation formula is as follows:

[0042] ,

[0043] ,

[0044] ,

[0045] In the formula,

[0046] U min Air velocity U when air is introduced g The minimum value, m / s;

[0047] U smax Theoretical maximum smoldering velocity, m / s;

[0048] k: Thermal conductivity coefficient of sludge, kJ / (m·s·℃);

[0049] q loss Heat loss during smoldering process, kJ / (m³) 2 ·s);

[0050] : The distance between the smoldering front and the smoldering peak temperature surface, in meters;

[0051] V2: The amount of oxygen required to burn 1 kg of oil sludge, in m 3 ;

[0052] T e Temperature at infinity from the furnace bottom, i.e., ambient temperature, in °C;

[0053] Q enHeat absorbed per unit mass of material, kJ / kg;

[0054] m0: Mass of all oil sludge in the smoldering pile, kg;

[0055] A: Base area of ​​the smoldering pile, in m² 2 ;

[0056] Y: Volume fraction of oxygen in the air, dimensionless, this value is a constant;

[0057] H: Height of smoldering material or the height of the interval from smoldering to spontaneous extinguishing, in meters;

[0058] Smoldering time, seconds.

[0059] Furthermore, in step S5, the energy consumption for air supply comes from the power consumption E of the blower. f Power consumption E f For E f The minimum operating time is the most economical condition, E f Determined by the following formula:

[0060] ,

[0061] ,

[0062] ,

[0063] In the formula,

[0064] P: Fan power, kW;

[0065] U g The range of values ​​for is (U min, U max ), calculate in (U min, U max E within the range f min, the air velocity at this time is U g ， U g ， The most economical operating condition is when air is being supplied.

[0066] Furthermore, the maximum smoldering velocity U smax It is related to the water content and oil content of the fuel; the higher the oil content, the better the U... smax The larger the size, the lower the moisture content, U smax The larger.

[0067] Furthermore, the maximum smoldering velocity U smaxIt is also related to the fuel particle size. The smaller the fuel particle size, the more difficult it is for air to pass through. However, the larger the fuel particle size, the lower the surface combustion efficiency and the longer the total combustion time. The appropriate fuel particle size can be selected through combustion experiments.

[0068] Furthermore, in step S6, when air is supplied at the theoretical air velocity U0, if the temperature at the top of the fuel pile no longer rises or begins to fall, it is considered that smoldering has ended.

[0069] The beneficial effects of this invention are as follows:

[0070] Based on the inherent parameters of the oil sludge fuel, the parameters that affect the combustion process during smoldering are obtained. Then, by controlling these parameters, the smoldering process is controlled, so that the smoldering process is at the highest combustion efficiency or the most economical condition. Alternatively, appropriate parameters can be selected according to the specific operating conditions to balance efficiency and cost, thus ensuring the treatment effect of smoldering in treating oil sludge. Attached Figure Description

[0071] Figure 1 This is a schematic diagram of the flow steps of the control method of the present invention;

[0072] Figure 2 This is a schematic diagram of the internal structure of the fuel pile during the smoldering process of the present invention;

[0073] Figure 3 This is a schematic diagram of the structure of the self-sustaining smoldering disposal system for the pile-type combustion of the present invention. Detailed Implementation

[0074] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0075] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0076] This invention relates to the control of the smoldering process in the treatment of oily sludge using a stack-type smoldering self-sustaining disposal system. There are generally two treatment methods for oily sludge: one is to maintain combustion at maximum efficiency after ignition to shorten treatment time, primarily used for rapid treatment of large quantities of oily sludge; the other is to control the airflow rate after ignition, ensuring the air supply equipment operates at its optimal condition while meeting smoldering requirements. This method offers the lowest cost and is suitable for energy-efficient treatment of small quantities of oily sludge.

[0077] The smoldering process includes the ignition stage, the smoldering stage, and the end and extinguishing of smoldering. Controlling the ignition stage allows the fuel to be ignited quickly and enter the smoldering stage more rapidly. Controlling the smoldering stage to keep it at the highest combustion efficiency or the most economical operating condition is achieved by controlling the airflow rate. When the oil content of the oily sludge decreases to the target value after combustion, it indicates that the smoldering has ended. Then, external means are used to extinguish the smoldering body, thus ending the smoldering process.

[0078] like Figure 1 , 2 As shown in Figure 3, this invention controls the smoldering process of a self-sustaining smoldering disposal system. The device for achieving smoldering in the self-sustaining smoldering disposal system is a smoldering chamber, which includes a smoldering chamber 1, a stack plate 2, an air supply structure 3, an ignition structure 4, and thermometers 5. The stack plate 2 is placed on the bottom plate of the smoldering chamber 1, and the fuel is placed on the stack plate 2. The air supply structure 3 and the ignition structure 4 are located below the stack plate 2. The ignition structure 4 is used to ignite the fuel, and the air supply structure 3 is used to supply air, so that the combustion is maintained at the highest combustion efficiency or the most economical condition. The thermometers 5 are horizontally spaced in the smoldering chamber 1 to monitor the temperature inside the fuel in real time.

[0079] Ignition structure 4 is horizontally and evenly arranged below stack plate 2, with ignition heads evenly spaced 250mm apart. It uses gas ignition. The air supply structure 3 includes a blower and an air supply pipe. The air supply pipe is horizontally and evenly arranged below ignition structure 4. The air supply pipe has openings around its perimeter at 500mm intervals, with a diameter of 10mm.

[0080] The thermometers 5 are arranged in an upper and lower layer, with each layer consisting of multiple horizontally arranged thermometers 5. They are used to monitor the temperature at various heights inside the fuel pile in real time, thereby determining the combustion height and degree, and then adjusting the air supply structure 3 to control the smoldering process.

[0081] like Figure 1 , 2 As shown, a method for controlling smoldering in oil sludge piles includes the following steps:

[0082] S1, Fuel Mixing: Mix oil sludge and quartz sand according to a set ratio to form fuel with a calorific value of 8500KJ / kg;

[0083] S2, Parameter Acquisition: Acquire various parameters of the fuel and determine the control parameters of the smoldering process based on the fuel parameters;

[0084] The control parameters include ignition layer thickness, air supply point, and air supply speed. Ignition layer thickness affects the efficiency of smoldering after the fuel is ignited. When an appropriate ignition layer thickness is used, the fuel in the ignition layer can enter the smoldering stage more quickly after being ignited, and the smoldering can reach the maximum combustion efficiency more quickly. Air supply point and air supply speed affect the ignition of the fuel. Appropriate air supply point and air supply speed can ignite the fuel in the ignition layer more quickly and stably, and enable it to ignite the fuel above more quickly, thereby entering the smoldering self-sustaining state more quickly.

[0085] S3, Preparation before ignition: Place the mixed fuel in the smoldering chamber to form a fuel pile, and set a temperature measuring point in the fuel pile;

[0086] S4, Ignition and Combustion: The bottom of the fuel pile is heated in a gradient to ignite it, and the temperature change of the fuel pile is monitored in real time. Once the bottom of the fuel pile is ignited, gas is supplied from the bottom of the fuel pile to keep it burning.

[0087] S5, Smoldering Self-Sustaining: After the formation of a smoldering front in the fuel pile is detected by real-time temperature monitoring, ignition is stopped and smoldering enters self-sustaining mode. At the same time, the gas supply is adjusted to control the smoldering, so that the combustion is always at the highest combustion efficiency to achieve the shortest combustion time, or the most economical gas supply is adopted to achieve the lowest cost.

[0088] S6, End of Smoldering: After the smoldering ends through real-time temperature monitoring, gas supply is stopped. After the fuel pile has completely cooled and extinguished, the waste from the combustion is cleaned up, completing one smoldering process.

[0089] like Figure 2 As shown, further, the ignition layer thickness is the ignition thickness in step S4 when the bottom of the fuel pile is ignited by gradient heating with gas, and is determined by the following formula:

[0090] ,

[0091] The thickness of the ignition layer is ,

[0092] In the formula,

[0093] x0: Smoldering front position, i.e., the position of the exothermic front or the position where the material just reaches the ignition point. Its value is the minimum smoldering thickness, in meters.

[0094] xS Location of the hot spot in the combustion zone, or the location of the peak smoldering temperature, in meters (m).

[0095] q v ，， Heat release rate per unit volume of material, kJ / (m³) 3 This value (·s) was obtained by thermogravimetric analysis and differential scanning calorimetry (TG-DSC), and the heat release rate was measured under constant ignition temperature conditions.

[0096] ρ m Material density, kg / m³ 3 This value is the density, obtained through experimental measurement;

[0097] C m Specific heat capacity of the material, kJ / (kg·℃), this value is obtained by thermogravimetric analysis and differential scanning calorimetry (TG-DSC);

[0098] U s : Smoldering peak propagation speed, i.e., actual smoldering speed, m / s. This value is calculated by the ratio of the straight-line distance between two adjacent thermocouples to the time difference between them reaching the peak temperature.

[0099] T0: Ignition temperature, also known as the flash point temperature, is the temperature at the smoldering front when the flame is turned off, in °C. This value is obtained by measuring a thermocouple.

[0100] T S : Smoldering peak temperature, °C, this value is obtained by thermocouple measurement;

[0101] q ， : Conductive heat flux density at x0, kJ / (m 2 (·s), this value is obtained by taking sludge samples and measuring them using a heat flow meter.

[0102] Furthermore, at x0, x S A thermometer 5 is installed at the location and 15cm above x0 for real-time temperature monitoring.

[0103] Furthermore, when x is measured S Once the temperature at the point reaches the ignition point To, the ignition layer at the bottom of the fuel pile is considered to be ignited. The moment when air is introduced into the smoldering body after the ignition layer at the bottom of the fuel pile is ignited is called the air supply point. Air is supplied to the ignition layer at the air supply point at the air supply speed, which intensifies the combustion of fuel in the ignition layer, accelerates the heat release, and can ignite the fuel above it, thus initiating the smoldering process.

[0104] The air supply velocity at the air supply point is determined by the following formula:

[0105] ,

[0106] At the air replenishment point, U... max The make-up air velocity is used for make-up air supply, and U in the formula s Take U smax Perform calculations.

[0107] In the formula,

[0108] U max Air velocity U when air is introduced g The maximum value, m / s, is obtained through theoretical calculations;

[0109] U g : Air velocity when air is introduced, m / s;

[0110] ρ g Air density, kg / m³ 3 This value is a constant;

[0111] c g Specific heat capacity of air, kJ / (kg·℃), this value is a constant;

[0112] Y O2 The mass fraction of oxygen in the air, dimensionless, and this value is a constant;

[0113] Q O : The amount of heat (kJ) released per unit (kg) of oxygen consumed, which is measured by thermogravimetric analysis and differential scanning calorimetry (TG-DSC).

[0114] The air content in the smoldering body voids is dimensionless. This value is determined by taking undisturbed samples within the bed and calculating the pressure drop.

[0115] U0: The total theoretical air velocity required for the complete smoldering oxidation of major elements such as C, H, N, and S under a certain mass of oil sludge material, in m / s. This value is calculated based on the proportion of various elements in the fuel.

[0116] Furthermore, when the temperature at x0 reaches the ignition point To, a smoldering front is formed in the fuel pile, and ignition is considered successful. That is, the fuel in the combustion zone will spontaneously ignite the fuel in the unburned zone above, and smoldering will enter a self-sustaining mode, burning the entire fuel pile completely from bottom to top. At this time, the ignition structure is turned off, ignition stops, and the fuel enters the smoldering self-sustaining state.

[0117] Furthermore, in step S5, during the smoldering process, the combustion efficiency can only be adjusted by controlling the airflow velocity, and there exists a minimum value U for the introduced airflow velocity. min Air velocity less than U minAt that time, insufficient oxygen supply and insufficient heat for combustion prevent smoldering from continuing, leading to extinguishing the flame. The air velocity is greater than U. min Afterward, smoldering can sustain combustion. As the air velocity increases, oxygen supply and heat release reach equilibrium at the theoretical air velocity U0, at which point smoldering reaches its highest combustion efficiency. Then, as the air velocity continues to increase, excess oxygen and higher wind speeds carry away combustion heat, causing fuel cooling and a decrease in combustion efficiency. When the heat carried away by the air velocity exceeds 10% of the released heat, insufficient heat transfer to the fuel leads to smoldering extinguishing. At this point, the incoming air velocity reaches its maximum value U. max Therefore, the airflow velocity needs to be U min and U max between.

[0118] Furthermore, in step S5, the shortest combustion time is achieved when combustion is consistently at its highest efficiency, meaning the fuel maintains its maximum smoldering rate U. smax Combustion can achieve the shortest combustion time. To ensure that combustion remains at its highest efficiency, the airflow velocity U needs to be controlled. g To take control.

[0119] Inlet air velocity , when U min <U g When U < U0, U s With U g Increases as U increases; when U0≤U g <U max At that time, U s With U g Increase and decrease; when U g When U = 0, the smoldering body has the maximum exothermic heat flux q. ， At this point, the maximum smoldering velocity U is reached. smax .

[0120] U min 、U0、U smax The calculation formula is as follows:

[0121] ,

[0122] ,

[0123] ,

[0124] In the formula,

[0125] U min Air velocity U when air is introduced g The minimum value, m / s, is obtained through theoretical calculation;

[0126] Usmax Theoretical maximum smoldering velocity, m / s, is obtained through theoretical derivation;

[0127] k: Thermal conductivity coefficient of oily sludge, kJ / (m·s·℃), this value is obtained by taking undisturbed soil of the filler and measuring it with a heat flow meter;

[0128] q loss Heat loss during smoldering process, kJ / (m³) 2 This value (·s) is derived from the heat loss of the reactor structure and the heat loss of the air.

[0129] : The distance between the smoldering front and the smoldering peak temperature surface, in meters. This value is obtained by measuring the spacing of the thermocouples.

[0130] V2: The amount of oxygen required to burn 1 kg of oil sludge, in m 3 This value was obtained through elemental analysis and calculation.

[0131] T e : Temperature at infinity from the furnace bottom, i.e., ambient temperature, °C, which is obtained by measuring an ambient thermometer;

[0132] Q en Heat absorbed per unit mass of material, kJ / kg, is obtained by thermogravimetric analysis and differential scanning calorimetry (TG-DSC).

[0133] m0: The total mass of oil sludge in the smoldering pile, in kg, which is obtained by weighing.

[0134] A: Base area of ​​the smoldering pile, in m² 2 This value was obtained through measurement and calculation;

[0135] Y: Volume fraction of oxygen in the air, dimensionless, this value is a constant;

[0136] H: Height of smoldering material or the height of the interval from smoldering to natural extinction, in meters (m). This value is obtained through measurement.

[0137] Smoldering time, which is the time required for the combustible material to burn completely, in seconds. This value is measured by timing.

[0138] Furthermore, in step S5, the energy consumption for air supply comes from the power consumption E of the blower. f Power consumption E f For E f The minimum operating time is the most economical condition, E f Determined by the following formula:

[0139] ,

[0140] ,

[0141] ,

[0142] In the formula,

[0143] P: Fan power, kW;

[0144] U g The range of values ​​for is (U min, U max ), calculate in (U min, U max E within the range f min, the air velocity at this time is U g ， U g ， The most economical operating condition is when air is being supplied.

[0145] In practical applications, the airflow velocity U at which combustion is always at its highest combustion efficiency is... g =U0 and the incoming air velocity U under the most economical operating condition g ， As an airflow velocity control range, the incoming airflow velocity should be controlled between U0 and U... g ， between.

[0146] Furthermore, in step S6, when air is supplied at the theoretical air flow rate U0, if the temperature at the top of the fuel pile no longer rises or begins to fall, it is considered that the oil content of the fuel is below 3‰, and the smoldering is considered to have ended. The end of smoldering is verified by changing the air flow rate. That is, if the temperature at the top of the fuel pile remains in a state of no longer rising or beginning to fall when the air flow rate is changed again, the smoldering is considered to have ended. After confirming that the smoldering has ended, the fuel is extinguished by means such as spraying or accelerating ventilation, the smoldering is extinguished, and the entire smoldering process ends.

[0147] Furthermore, the temperature measurement point during ignition testing is set at x S At x0 and x0, respectively, we can confirm successful ignition and successful entry into smoldering mode.

[0148] Furthermore, the maximum smoldering velocity U smax It is related to the water content and oil content of the fuel. The higher the oil content, the more heat is released during combustion, and the higher the peak combustion temperature. Therefore, U smax The larger the size, the lower the water content, and the less heat is absorbed during water evaporation, which also makes U... smax The larger.

[0149] Furthermore, the maximum smoldering velocity U smaxIt is also related to fuel particle size. The smaller the fuel particle size, the more difficult it is for air to pass through. However, the larger the fuel particle size, the lower the surface combustion efficiency and the longer the total combustion time. A suitable fuel particle size is selected through combustion experiments. Specifically, combustion experiments with fuels of different particle sizes are conducted in a muffle furnace to obtain the complete combustion time for different particle sizes, thus obtaining the combustion rate of fuels with different particle sizes. In specific selection, a combustion rate higher than the maximum smoldering rate U is chosen. smax The fuel particle size.

[0150] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for controlling smoldering in oil sludge piles, characterized in that, Includes the following steps: S1, Fuel Mixing: Mix oil sludge and quartz sand according to a set ratio to form fuel; S2, Parameter Acquisition: Acquire various parameters of the fuel and determine the control parameters of the smoldering process based on the fuel parameters; S3, Preparation before ignition: Place the mixed fuel in the smoldering chamber to form a fuel pile, and set a temperature measuring point in the fuel pile; S4, Ignition and Combustion: The bottom of the fuel pile is heated in a gradient to ignite it, and the temperature change of the fuel pile is monitored in real time. Once the bottom of the fuel pile is ignited, gas is supplied from the bottom of the fuel pile to keep it burning. S5, Smoldering Self-Sustaining: After successful ignition, ignition is stopped and smoldering enters self-sustaining mode. At the same time, the gas supply is adjusted to control smoldering, so that combustion is always at the highest combustion efficiency to achieve the shortest combustion time, or the most economical gas supply is adopted to achieve the lowest cost. S6, End of smoldering: After the smoldering ends through real-time temperature monitoring, gas supply is stopped. After the fuel pile has completely cooled and extinguished, the waste after combustion is cleaned up, completing one smoldering process. In step S2, various parameters of the fuel are collected and tested, and the ignition layer thickness, make-up air point, and make-up air speed are determined based on the fuel parameters. The ignition layer thickness is the ignition thickness during step S4 when the bottom of the fuel pile is ignited by gradient heating of the fuel gas, and is determined by the following formula: ， The thickness of the ignition layer is 2*( ), In the formula, : Smoldering front position, i.e., the position of the exothermic front or the position where the material just reaches the ignition point, its value is the minimum smoldering thickness, m; Location of the hot spot in the combustion zone, or the location of the peak smoldering temperature, in meters (m). Heat release rate per unit volume of material, kJ / (m³) 3 ·s); Material density, kg / m³ 3 ; Specific heat capacity of the material, kJ / (kg·℃); : Smoldering peak propagation speed, m / s; Ignition temperature, also known as flash point, is the temperature at the smoldering front when the flame is turned off, in °C. Peak smoldering temperature, °C; : Conductive heat flux density at the point, kJ / (m 2 ·s).

2. The control method for smoldering disposal of oil sludge piles according to claim 1, characterized in that: When measured Once the temperature at the point reaches the ignition point To, it is considered that the bottom of the fuel pile is ignited. The moment when air is introduced into the smoldering body for makeup air is called the makeup air point. The makeup air rate at the makeup air point is determined by the following formula: ， The air supply point should be selected slightly below... The make-up air velocity is used for make-up air supply, and in the formula... Pick Perform calculations. In the formula, Airflow velocity when air is introduced The maximum value, m / s; : Air velocity when air is introduced, m / s; Air density, kg / m³ 3 ; Specific heat capacity of air, kJ / (kg·℃); The mass fraction of oxygen in the air, dimensionless, and this value is a constant; Heat (kJ) released per unit (kg) of oxygen consumed; The proportion of air in the voids of a smoldering body, dimensionless; Given a fixed mass of oil sludge, the total theoretical air velocity required for the complete smoldering oxidation of the main elements C, H, N, and S is given in m / s.

3. The control method for smoldering oil sludge pile disposal according to claim 1, characterized in that: In step S5, the temperature is measured in real time. When the temperature at the point reaches the ignition point To, a smoldering front forms on the fuel pile, ignition is successful, and then ignition is stopped.

4. The control method for smoldering oil sludge pile disposal according to claim 1, characterized in that: In step S5, the shortest combustion time is achieved when combustion is consistently at its highest efficiency, meaning the fuel maintains its maximum smoldering rate. Combustion will achieve the shortest combustion time. To ensure that combustion remains at its highest efficiency, the airflow velocity needs to be controlled. To take control; Inlet air velocity ,when < < hour, along with Increase and increase; when ≤ < hour, along with Increase and decrease; when At that time, the smoldering body has the maximum exothermic heat flux. At this point, the maximum smoldering rate is reached. ; , , The calculation formula is as follows: ， ， ， In the formula, Airflow velocity when air is introduced The minimum value, m / s; Theoretical maximum smoldering velocity, m / s; : Thermal conductivity of sludge, kJ / (m·s·℃); Heat loss during smoldering process, kJ / ( ·s); : The distance between the smoldering front and the smoldering peak temperature surface, in meters; The amount of oxygen required to burn 1 kg of oil sludge, in m 3 ; Temperature at infinity from the furnace bottom, i.e., ambient temperature, in °C; Heat absorbed per unit mass of material, kJ / kg; Mass of all oil sludge in the smoldering pile, kg; : Base area of ​​smoldering pile, m 2 ; : Volume fraction of oxygen in the air, dimensionless, this value is a constant; : Height of smoldering material or the height of the interval from smoldering to spontaneous extinguishing, in meters; Smoldering time, seconds.

5. The control method for smoldering disposal of oil sludge piles according to claim 4, characterized in that: In step S5, the energy consumption for air supply comes from the power consumption of the blower. Power consumption for This is the most economical operating condition. Determined by the following formula: ， ， ， In the formula, Fan power, Kw; The range of values ​​is Calculate Within range The air velocity at this time is ,use The most economical operating condition is when air is being supplied.

6. The method for controlling smoldering in oil sludge piles according to claim 4, characterized in that: Maximum smoldering speed It is related to the water content and oil content of the fuel; the higher the oil content, the better. The larger the size, the lower the moisture content. The larger.

7. The control method for smoldering disposal of oil sludge piles according to claim 4, characterized in that: Maximum smoldering speed It is also related to the fuel particle size. The smaller the fuel particle size, the more difficult it is for air to pass through. However, the larger the fuel particle size, the lower the surface combustion efficiency and the longer the total combustion time. The appropriate fuel particle size can be selected through combustion experiments.

8. The control method for smoldering disposal of oil sludge piles according to claim 1, characterized in that: In step S6, based on the theoretical airflow velocity When air is supplied, if the temperature at the top of the fuel pile no longer rises or begins to drop, it is considered that smoldering has ended.

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