A monitoring device and method for thickness and temperature of refractory brick layer

Abstract

The present invention discloses a monitoring device and method for the thickness and temperature of a refractory brick layer. The monitoring device for the thickness of the refractory brick layer includes a measuring component connected to a furnace body to be monitored, and also includes a calculation module I, a calculation module II and a calculation module III; the furnace body to be monitored is a gasification furnace, which includes a liquid slag layer, a refractory brick layer and a metal wall from the inside to the outside, and the refractory brick layer includes a fire-facing brick layer, a backing brick layer and an insulating brick layer from the inside to the outside; the calculation module I is used to calculate the thickness of the liquid slag layer through the mass conservation equation of the liquid slag layer flow heat transfer process; the calculation module II is used to calculate the heat flux density passing through the metal wall; the calculation module III is used to obtain the thickness of the fire-facing brick layer, the backing brick layer and the insulating brick layer. The monitoring device and method provided by the present invention can accurately monitor the thickness of the refractory brick layer by analyzing the slag flow and heat transfer process.

Description

Technical Field

[0001] The invention relates to a device and method for monitoring the thickness and temperature of a refractory brick layer. Background Art

[0002] Coal gasification technology is one of the key technologies for clean and efficient utilization of coal and other carbon-containing materials today. It is the main way to convert primary energy into clean secondary energy and chemical products. This technology is mainly used in synthetic ammonia, synthetic methanol, refinery hydrogen production, blast furnace reduction ironmaking chemical metallurgical industry and combined cycle power generation equipment. The development of coal gasification technology has gone through fixed bed gasification technology (represented by Lurgi technology and Saiding gasification technology), fluidized bed gasification technology (represented by HTW and Ugas technology) and entrained bed gasification technology (represented by Texaco, Shell, multi-nozzle, HT-L, SE technology). With the technical demand for large-scale energy safe, clean and efficient conversion, entrained bed coal gasification technology with high gasification temperature and pressure, large load, and wide range of coal adaptability has become the main direction of coal gasification technology development and industrial application.

[0003] In the entrained-bed coal gasification technology, an efficient and reliable gasifier is the key and core equipment of the entire technology. The entrained-bed gasifier is a multiphase complex reactor with harsh conditions, high temperature and high pressure (4.0-6.5MPa, ~1300℃). Existing detection methods cannot accurately and long-term monitor it, making it in a "black box" operation state for a long time. According to the thermal insulation lining structure of the gasifier, it can be divided into refractory brick lined gasifiers (such as: multi-nozzle gasifier, GE gasifier, first-generation Tsinghua furnace, multi-element slurry gasifier) ​​and water-cooled wall lined gasifiers (such as: Aerospace furnace, Shell furnace, second-generation Tsinghua furnace, GSP furnace), etc. The coal gasification technology using water-coal slurry as raw material generally uses a refractory brick lined gasifier, and the gasification technology using pulverized coal as raw material generally uses a water-cooled wall lined gasifier. The water-coal slurry refractory brick lining gasification technology is widely used in the coal chemical industry due to its advantages such as short process flow, simple gasifier structure, low heat loss, and high chemical energy conversion rate. It accounts for about 65% of my country's modern coal gasification technology. The thickness of the refractory brick layer is one of the key parameters of the gasifier structure. During the operation of the gasifier, the refractory bricks are gradually corroded and thinned under the erosion of high-temperature slag. When the thickness of the refractory brick layer is less than a certain critical value, its thermal insulation effect is greatly reduced, and the metal shell of the gasifier is overheated, which directly affects the safety of the metal shell of the gasifier. Therefore, it is urgent to develop a system and method that can monitor the temperature and thickness of the refractory brick layer of the gasifier online. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defect that the temperature and thickness of the refractory brick layer in the high-temperature and high-pressure gasification furnace cannot be directly measured in the prior art, and to provide a monitoring device and method for the thickness and temperature of the refractory brick layer. The monitoring device and method provided by the present invention can accurately monitor the thickness of the refractory brick layer by analyzing the slag flow and heat transfer process on the inner wall of the gasification furnace, providing certain guidance for industrial operations.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A monitoring device for the thickness of a refractory brick layer, comprising a measuring component connected to a furnace body to be monitored, the monitoring device further comprising a calculation module I, a calculation module II and a calculation module III;

[0007] The measuring component is used to measure the parameters required by the calculation module I, the calculation module II and the calculation module III when running calculations;

[0008] The furnace body to be monitored is a gasification furnace, which includes a liquid slag layer, a refractory brick layer and a metal wall from the inside to the outside, and the refractory brick layer includes a fire-facing brick layer, a backing brick layer and an insulation brick layer from the inside to the outside;

[0009] The calculation module I is used to calculate the thickness of the liquid slag layer by using the mass conservation equation of the flow and heat transfer process of the liquid slag layer;

[0010] The calculation module II is used to calculate the heat flux density passing through the metal wall;

[0011] The calculation module III is used to substitute the heat flux density passing through the metal wall and the thickness of the slag layer into the heat flux density equation of "passing through the fire-facing brick layer, passing through the backing brick layer and passing through the insulation brick layer" established based on the law of energy conservation, and obtain the thickness of the fire-facing brick layer, the backing brick layer and the insulation brick layer respectively. The sum of the thickness of the fire-facing brick layer, the thickness of the backing brick layer and the insulation brick layer is the thickness of the refractory brick layer;

[0012] The calculation module I is electrically connected to the calculation module III for transmitting the calculated thickness of the liquid slag layer to the calculation module III; the calculation module II is electrically connected to the calculation module III for transmitting the calculated heat flux density passing through the metal wall to the calculation module III.

[0013] The present invention predicts the thickness of the refractory brick layer and the thickness of each layer in the gasifier by analyzing the slag flow and heat transfer process of the liquid slag layer in the gasifier based on atmospheric convection heat exchange, ambient temperature, the temperature of the outer wall of the metal wall and the temperature in the furnace of the gasifier. The high-temperature gas in the furnace of the gasifier transfers heat to the inner wall of the gasifier through radiation heat transfer and convection heat transfer, and the slag is deposited on the inner wall of the gasifier to form a liquid slag layer. After the inner wall of the gasifier absorbs the incoming heat and the heat substituted by the slag deposition, it transfers the heat to the refractory brick layer and the metal wall in turn based on heat conduction, and finally transfers it to the atmosphere. The temperature rise of the atmosphere is related to the heat conduction, the slag deposition, and the thickness of the liquid slag layer. Therefore, by measuring the temperature rise of the atmosphere, a slag deposition flow and heat transfer model on the inner wall of the gasifier is established to infer the thickness of the refractory brick layer. In the present invention, the slag of the liquid slag layer needs to be in liquid state and cooperate with the above three different calculation modules in the present invention to achieve real-time and accurate measurement of the thickness of the refractory brick layer.

[0014] In the present invention, those skilled in the art know that the measuring component can be reasonably set according to the parameters required in the calculation process of the calculation module I, the calculation module II and the calculation module III.

[0015] For example, in the process of calculating the thickness of the liquid slag layer in the calculation module I, it is necessary to know the amount of slag deposited on the inner wall surface of the gasifier, and accordingly a flow meter for measuring the amount of slag is required. Those skilled in the art know that the amount of dry coal entering the gasifier is generally obtained through a coal slurry flow meter or a coal powder flow meter, and then the slag amount is calculated in combination with the ash content in the coal measured by an ash meter.

[0016] For example, when the calculation module II calculates the heat flux density of the outer wall surface of the metal wall, it needs to know the temperature of the outer wall surface of the metal wall and the ambient temperature, so the temperature measuring component 1 is required to measure the temperature of the outer wall surface of the metal wall, and the temperature measuring component 2 is required to measure the ambient temperature close to the outer wall surface of the metal wall. The temperature measuring component 1 or the temperature measuring component 2 can be a thermocouple, and the thermocouple is, for example, an infrared thermometer. The number of the temperature measuring components 2 is, for example, 3.

[0017] For example, when the calculation module III calculates the thickness of the refractory brick layer, it needs to know the gas temperature near the inner wall surface in the furnace of the gasifier, so it is necessary to set a plurality of temperature measuring components 3 in the furnace to measure the temperature in the furnace. The temperature measuring components in the furnace are, for example, 2 to 6 to measure the temperature from top to bottom in the furnace, and the temperature measuring components can be thermocouples.

[0018] In the present invention, the calculation method of the calculation module 1 is preferably as follows:

[0019] Assuming that 70wt.% of the coal added to the gasifier is produced after the gasification reaction and is deposited on the inner wall surface of the fire-facing brick layer to form the liquid slag layer, and is evenly distributed, and the slag flow in the liquid slag layer satisfies the Newtonian fluid flow, the mass conservation calculation formula established for the flow heat transfer process of the liquid slag layer is shown in equation ①:

[0020]

[0021] In equation ①, δ s,i It refers to the thickness of the liquid slag layer, in m; ρ s is the density of the slag in the liquid slag layer; m in,j is the amount of slag deposited on the inner wall of the gasifier, in kg, and its value is m in,j = coal quantity × ash content × 70%; L i is the equivalent circumference of the straight section of the cylinder in the gasifier, in m; x is the displacement of the particle in the liquid slag layer; i is the coordinate identifier of the position of the point, j is the coordinate range from the top of the gasifier to the i-th point, and the physical meaning is that the amount of slag at the i-th point is the sum of all deposited particles from the top to the i-th point;

[0022] v i (x) is the velocity distribution function in the slag layer, which is obtained by the momentum equation ②:

[0023] The boundary condition of equation ② is

[0024] In equation ②, η s is the dynamic viscosity of the liquid slag layer, v is the velocity of slag flow, g is the gravitational acceleration, β is the inclination angle of slag flowing on the inner wall of the gasifier, ρ s It refers to the density of slag in the slag layer, and τ is the shear force of the inner wall surface of the gasifier.

[0025] Among them, those skilled in the art know that the gasifier body includes a dome and a straight section of the cylinder matched with the dome.

[0026] The equivalent circumference of the straight section of the cylinder in the gasifier can be calculated according to the conventional method in the art, generally using the formula L = π (D - δ s -x) is calculated, where D is the inner diameter of the gasifier, due to (δ s -x) is very small relative to D, only 10 times its magnitude -3 , so the calculation formula of L can be simplified to L = πD.

[0027] Among them, ρ sThe value of refers to the conventional value in the art, such as 2500 kg / m 3 .

[0028] Among them, τ is related to the structure and operating state of the gasifier, and can generally be approximated as τ = 0.0303ρ g u0 2 ρ g It refers to the density of the synthesis gas in the gasifier, u0 2 It refers to the surface velocity of the liquid slag layer. Those skilled in the art know that the g Calculated based on gasifier type, temperature and pressure.

[0029] Among them, η s It is the basic physical property data of slag, which needs to be obtained through analysis and testing. Its value is related to the temperature distribution in the slag layer and can be obtained through the viscosity-temperature characteristic curve of the slag and the temperature distribution in the slag layer.

[0030] In the present invention, in the calculation module II, the calculation formula for calculating the heat flux density of the outer wall surface heat transfer of the metal wall is preferably as follows:

[0031] q out,i =2πΔzr0(T m,i -T air )h air,i ③

[0032] T m,i is the temperature of the outer wall of the metal wall, T air is the ambient temperature, h air,i is the convective heat transfer coefficient between the outer wall of the metal wall and the atmosphere, △z is the height of the fire-facing brick layer, r0 is the radius of the gasifier, and the radius of the gasifier refers to the distance from the outer wall of the metal wall to the central axis of the gasifier; the height of the fire-facing brick layer is generally the height assuming that the bricks in the fire-facing brick layer are not misaligned up and down.

[0033] In equation ③, h air According to formula ④, it is calculated as follows:

[0034]

[0035] In equation ④, h conv is the natural convection constant, and c is the constant of the metal wall.

[0036] Among them, T m,i It is generally measured by a thermocouple arranged on the outer wall surface of the metal wall of the gasifier. The thermocouple is generally an infrared thermometer, or a surface thermocouple, preferably an infrared thermometer.

[0037] Among them, Tair Generally, the heat flux is calculated based on natural convection heat transfer by setting a plurality of ambient temperature thermocouples on the outer wall of the metal wall. The number of the ambient temperature thermocouples is, for example, 3, to obtain an average value.

[0038] Among them, h conv It can be obtained by taking values ​​and making corrections according to the actual situation on site, and is generally calculated by the following equation ④-1:

[0039] In equation ④-1, L is the height of the straight section of the cylinder in the gasifier. conv Preferably 2.55W / m 2 ·K.

[0040] Wherein, in equation ④, the c is preferably 4.06W / m 2 ·K 4 .

[0041] In the present invention, in the calculation module III, the calculation formula is preferably as follows:

[0042]

[0043] In equation ⑤, q ref,i =q out,i , T g,i is the gas temperature near the inner wall surface in the furnace of the gasifier, measured by the thermocouple in the gasifier; T m,i is the temperature of the outer surface of the metal wall; g,i The value of is the same as the value of the interface temperature between the liquid slag layer and the gas.

[0044] r3=r2-δ r,1 ,r4=r3-δ r,2 ,r5=r4-δ r,3 ,r6=r5-δ s,i ; r5 is the inner diameter of the fire-facing brick layer, r6 is the inner diameter of the liquid slag layer, r4 is the inner diameter of the backing brick layer, and r3 is the inner diameter of the insulation brick layer;

[0045] k r,1 ,k r,2 ,k r,3 ,k s,i The thermal conductivity of the insulating brick layer, the thermal conductivity of the backing brick layer, the thermal conductivity of the fire-facing brick layer and the thermal conductivity of the liquid slag layer are obtained by querying the physical property parameters;

[0046] δ r,1 ,δ r,2 ,δ r,3 and δs,i They are respectively the thickness of the insulation brick layer, the thickness of the backing brick layer, the thickness of the fire-facing brick layer and the thickness of the slag layer; wherein the thickness of the insulation brick layer and the backing brick layer are both constant values.

[0047] In the present invention, the monitoring device for the thickness of the refractory brick layer preferably also includes a computing terminal to realize real-time online calculation of the thickness of the refractory brick layer, which is used for the calculation of the computing module I, the computing module II and the computing module III.

[0048] The computing terminal is, for example, a computer or a programmable controller.

[0049] In the present invention, a refractory wool layer is preferably further provided between the metal wall and the insulating brick layer to achieve more accurate measurement.

[0050] When the refractory wool layer is also included, the monitoring device of the present invention can also calculate the thickness of the refractory wool layer and the metal wall by substituting the following formula into the equation ⑤:

[0051] r0=r m ,r1=r0-δ m ,r2=r1-δ r,c , wherein r2 is the inner diameter of the refractory wool layer, r1 is the inner diameter of the metal wall, and r0 is the radius of the gasifier;

[0052] k m , k r,c are the thermal conductivity of the metal wall and the thermal conductivity of the refractory wool layer, respectively, which are obtained by querying the physical property parameters, where k r,1 =k r,c , k r,0 =k m ;

[0053] δ m , δ r,c are the thickness of the metal wall and the thickness of the refractory wool layer respectively. The thickness of the metal wall and the refractory wool layer are constant values.

[0054] The present invention also provides a device for monitoring the temperature of a refractory brick layer, which comprises the device for monitoring the thickness of the refractory brick layer and a calculation module IV, wherein the calculation module IV is used to establish the following energy conservation equation:

[0055] q out，i ×A m =q ref1 ×A r1 =q ref2 ×A r2 =q ref3 ×A r3=q refs ×A s ⑥

[0056] In equation ⑥, q out,i ,q ref1 ,q ref2 ,q ref3 ,q refs A refers to the heat flux density passing through the metal wall, the insulating brick layer, the backing brick layer, the fire-facing bricks and the liquid slag layer respectively; m , A r1 , A r2 , A r3 , A s They respectively refer to the radial heat transfer area of ​​the metal wall, the radial heat transfer area of ​​the insulation brick layer, the radial heat transfer area of ​​the backing brick layer, the radial heat transfer area of ​​the fire-facing brick layer and the radial heat transfer area of ​​the liquid slag layer;

[0057] The calculation module III is electrically connected to the calculation module IV, and is used to transmit the thickness of the refractory brick layer in the calculation module III to the calculation module IV.

[0058] In the present invention, the device for monitoring the temperature of the refractory brick layer preferably also includes a computing terminal to achieve real-time online calculation of the temperature of the refractory brick layer for calculation in the computing module IV.

[0059] The computing terminal is, for example, a computer or a programmable controller.

[0060] In the present invention, when a refractory wool layer is included between the metal wall and the insulation brick layer, the temperature of the refractory wool layer is determined by q out,i ×A m =q refc ×A rc The equation is calculated, q refc Refers to the heat flux density passing through the refractory wool layer, A rc Refers to the radial heat transfer area of ​​the refractory wool layer.

[0061] The present invention also provides a method for monitoring the thickness of a refractory brick layer, which comprises the following steps: a heat transfer process of a gasifier is carried out from the inside to the outside in sequence between a slag layer, a refractory brick layer, a metal wall and the atmosphere;

[0062] The refractory bricks include fire-facing bricks, backing bricks and insulation bricks from the inside to the outside;

[0063] The steps for calculating the thickness of the refractory brick layer are as follows:

[0064] Step (1), assuming that 70wt.% of the coal added to the gasifier is deposited on the inner wall of the fire-facing brick layer after gasification reaction to form the slag layer, and the slag flow in the slag layer satisfies the Newtonian fluid flow. The mass conservation equation ① is established for the flow and heat transfer process of the slag layer, and the thickness of the slag layer is obtained:

[0065]

[0066] In equation ①, δ s,i It refers to the thickness of the liquid slag layer, in m; ρ s is the density of the slag in the liquid slag layer; m in,j is the amount of slag deposited on the inner wall of the gasifier, in kg, and its value is m in,j = coal quantity × ash content × 70%; L i is the equivalent circumference of the straight section of the cylinder in the gasifier, in m; x is the displacement of the particle in the liquid slag layer; i is the coordinate identifier of the position of the point, j is the coordinate range from the top of the gasifier to the i-th point, and the physical meaning is that the amount of slag at the i-th point is the sum of all deposited particles from the top to the i-th point;

[0067] v i (x) is the velocity distribution function in the slag layer, which is obtained by the momentum equation ②:

[0068] The boundary condition of equation ② is

[0069] In equation ②, η s is the dynamic viscosity of the liquid slag layer, v is the velocity of slag flow, g is the gravitational acceleration, β is the inclination angle of slag flowing on the inner wall surface of the gasifier, ρ s It refers to the density of the slag in the liquid slag layer, τ is the shear force on the inner wall of the gasifier;

[0070] Step (2), calculating the heat flux density passing through the metal wall:

[0071] q out,i =2πΔzr0(T m,i -T air )h air,i ③

[0072] T m,i is the temperature of the outer wall of the metal wall, T air is the ambient temperature, h air,i is the convective heat transfer coefficient between the outer wall of the metal wall and the atmosphere, △z is the height of the fire-facing brick layer; the height of the fire-facing brick layer is generally the height assuming that the bricks in the fire-facing brick layer are not misaligned up and down.

[0073] In equation ③, h air According to formula ④, it is calculated as follows:

[0074]

[0075] In equation ④, T m,i is the temperature of the outer wall of the metal wall, T air is the ambient temperature, h air,i is the convective heat transfer coefficient between the outer wall of the metal wall and the atmosphere, h conv is the natural convection constant, c is the constant of the metal wall;

[0076] Step (3): convert the q calculated in step (2) into ref,i Substitute into equation ⑤, and q ref,i =q out,i , calculate r j :

[0077]

[0078] Among them, T g,i is the gas temperature near the inner wall surface in the furnace of the gasifier, measured by the thermocouple in the gasifier; T m,i is the temperature of the outer surface of the metal wall; g,i The value of is the same as the value of the interface temperature between the slag layer and the gas;

[0079] According to equation ⑤, r j Substitute into the following formula to calculate the thickness of each layer:

[0080] r2=r1-δ r,c ,r3=r2-δ r,1 ,r4=r3-δ r,2 ,r5=r4-δ r,3 ,r6=r5-δ s,i ; r5 is the inner diameter of the fire-facing brick layer, r6 is the inner diameter of the liquid slag layer, r4 is the inner diameter of the backing brick layer, and r3 is the inner diameter of the insulation brick layer;

[0081] k r,1 ,k r,2 ,k r,3 ,k s,i The thermal conductivity of the insulating brick layer, the thermal conductivity of the backing brick layer, the thermal conductivity of the fire-facing brick layer and the thermal conductivity of the slag layer are obtained by querying the physical property parameters;

[0082] δ r,1 ,δ r,2 ,δ r,3and δ s,i are respectively the thickness of the heat-insulating brick layer, the thickness of the backing brick layer, the thickness of the fire-facing brick layer and the thickness of the liquid slag layer; wherein the thickness of the heat-insulating brick layer and the backing brick layer are both constant values;

[0083] Solve equations ①~⑤ together to find δ r,1 , δ r,2 and δ r,3 , and the sum of them can be used to calculate the thickness of the refractory brick layer.

[0084] In the present invention, the temperature of the slag in the liquid slag layer is preferably above 1300°C.

[0085] In the present invention, the equivalent circumference of the straight section of the cylinder in the gasifier can be calculated according to the conventional method in the art, generally using the formula L = π (D-δ s -x) is calculated, where D is the inner diameter of the gasifier, due to (δ s -x) is very small relative to D, only 10 times its magnitude -3 , so the calculation formula of L can be simplified to L = πD.

[0086] In the present invention, the inner diameter of the fire-facing brick layer generally refers to the distance from the axis of the gasifier to the outermost layer of the fire-facing bricks. r4 is the inner diameter of the backing brick layer, r3 is the inner diameter of the insulation brick layer, r2 is the inner diameter of the refractory wool layer, and r1 is the inner diameter of the metal wall, which have the same meaning as the inner diameter of the fire-facing brick layer.

[0087] In the present invention, in equations ① and ②, ρ s The value of can be conventional in the art, for example, 2500 kg / m 3 .

[0088] In the present invention, τ is related to the structure and operation state of the gasifier, and can generally be approximated as τ = 0.0303ρ g u0 2 ρ g It refers to the density of the synthesis gas in the gasifier, u0 2 It refers to the surface velocity of the liquid slag layer. Those skilled in the art know that the g Calculated based on gasifier type, temperature and pressure.

[0089] In the present invention, in equation ②, η s It is the basic physical property data of slag, which needs to be obtained through analysis and testing. Its value is related to the temperature distribution in the slag layer and can be obtained through the viscosity-temperature characteristic curve of the slag and the temperature distribution in the slag layer.

[0090] In the present invention, in equation ③ and equation ④, T m,iIt is generally measured by a thermocouple arranged on the outer wall surface of the metal wall of the gasifier. The thermocouple is generally an infrared thermometer, or a surface thermocouple, preferably an infrared thermometer.

[0091] In the present invention, in equation ③ and equation ④, T air Generally, the heat flux is calculated based on natural convection heat transfer by setting a plurality of ambient temperature thermocouples on the outer wall of the metal wall. The number of the ambient temperature thermocouples is, for example, 3, to obtain an average value.

[0092] In the present invention, those skilled in the art know that h in equation ④ conv It can be obtained by taking values ​​and making corrections according to the actual situation on site, and is generally calculated by the following equation ④-1:

[0093]

[0094] In equation ④-1, L is the height of the straight section of the cylinder in the gasifier.

[0095] Among them, the h conv Preferably 2.55W / m 2 ·K.

[0096] In the present invention, in equation ④, the c is preferably 4.06W / m 2 ·K 4 .

[0097] In the present invention, when a refractory wool layer is further included between the metal wall and the insulating brick layer, the monitoring method can also calculate the thickness of the refractory wool layer by substituting the following formula into equation ⑤:

[0098] r0=r m ,r1=r0-δ m ,r2=r1-δ r,c , wherein r2 is the inner diameter of the refractory wool layer, r1 is the inner diameter of the metal wall, and r0 is the radius of the gasifier, and the radius of the gasifier refers to the distance from the outer wall surface of the metal wall to the central axis of the gasifier;

[0099] k m , k r,c are the thermal conductivity of the metal wall and the thermal conductivity of the refractory wool layer, respectively, which are obtained by querying the physical property parameters, where k r,1 =k r,c , k r,0 =k m ;

[0100] δ m , δ r,care the thickness of the metal wall and the thickness of the refractory wool layer respectively. The thickness of the metal wall and the refractory wool layer are constant values.

[0101] The present invention also provides a method for monitoring the temperature of a refractory brick layer. According to the thickness value of the refractory brick layer obtained by the above-mentioned online monitoring method for the thickness of the refractory brick layer, an energy conservation equation ⑥ is established:

[0102] q out，i ×A m =q ref1 ×A r1 =q ref2 ×A r2 =q ref3 ×A r3 =q refs ×A s ⑥

[0103] q out,i ,q ref1 ,q ref2 ,q ref3 ,q refs A refers to the heat flux density passing through the metal wall, the heat flux density of the insulation brick layer, the heat flux density of the backing brick layer, the heat flux density of the fire-facing bricks and the heat flux density of the slag layer respectively; m , A r1 , A r2 , A r3 , A s They respectively refer to the radial heat transfer area of ​​the metal wall, the radial heat transfer area of ​​the insulating brick layer, the radial heat transfer area of ​​the backing brick layer, the radial heat transfer area of ​​the fire surface brick layer and the radial heat transfer area of ​​the slag layer; the temperature of the refractory brick layer can be obtained.

[0104] In the present invention, when a refractory wool layer is included between the metal wall and the insulating brick layer, the temperature of the refractory wool layer can be measured by q out,i ×A m =q refc ×A rc The equation is calculated, qr efc Refers to the heat flux density passing through the refractory wool layer, A rc Refers to the radial heat transfer area of ​​the refractory wool layer.

[0105] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0106] The positive progressive effect of the present invention is that the method provided by the present invention monitors the temperature and thickness of the refractory brick layer based on the heat transfer principle; specifically, by analyzing the slag flow and heat transfer process on the inner wall of the gasifier, the thickness of the refractory brick layer in the gasifier and the temperature of each layer of bricks are predicted based on atmospheric convection heat exchange, thereby providing guidance for gasification operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0107] Figure 1 This is a schematic diagram of the structure of the gasifier in Example 1.

[0108] Figure 2 This is a schematic diagram of the slag flow and heat transfer principle in the gasifier in Example 1.

[0109] Figure 3 This is a schematic diagram of the structure of the refractory brick layer monitoring device in Example 1.

[0110] Figure 4 This is a flow chart of the calculation principle in Example 1.

[0111] Figure 5 This is the temperature distribution of the outer surface of the metal wall obtained by real-time measurement in Example 1.

[0112] Figure 6 The gas temperature distribution near the inner wall surface in the furnace of the gasifier obtained by real-time measurement in Example 1.

[0113] Figure 7 It is the thickness of the fire-facing brick layer measured in real time in the embodiment.

[0114] Reference numerals:

[0115] Figure 1 , 1-outer surface of the metal wall; 2-infrared thermometer;

[0116] Figure 2 , 11-liquid slag layer; 12-fire facing brick layer; 13-backing brick layer; 14-insulating brick layer; 15-refractory wool layer; 16-metal wall; and the radial direction of the furnace body is set to x, and the axial direction of the furnace body is set to z. DETAILED DESCRIPTION

[0117] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0118] Example 1

[0119] The structural schematic diagram of the gasifier in this embodiment is as follows Figure 1 As shown, Figure 11 is the outer wall of the metal wall, and 2 is an infrared thermometer. In this embodiment, the operating pressure of the refractory brick-lined gasifier is 6.5 MPa, the temperature is 1300°C, the radius (outer diameter) of the gasifier is 1.7 m, the height of the refractory brick head of the gasifier is 1.7 m, and the height of the straight section of the cylinder is 8.3 m (i.e. Figure 5 , Figure 6 and Figure 7 The gasifier height in the horizontal axis). The rated coal slurry flow rate is 27.4 kg / s, the coal slurry concentration is 60%, and the ash content of the coal fluctuates between 6.8% and 12%. During the calculation process, it is necessary to find the physical property data of the refractory brick layer and the air property data, as shown in Table 1 below.

[0120] Table 1

[0121] parameter value parameter value - - <![CDATA[r0 r m mm]]> 3200 <![CDATA[η s (T)Pa·s]]> <![CDATA[η(T)=1.41×10 8 and -0.011T ]]> <![CDATA[δ m mm,k m W / m·K]]> 100,17 <![CDATA[ρ s kg / m 3 ]]> 2500 <![CDATA[δ c mm,k c W / m·K]]> 19,0.9 CJ / kg·K 1670 <![CDATA[δ r,1 mm,k r,1 W / m·K]]> 230,4.0 <![CDATA[k s (T)W / m·K]]> <![CDATA[k s (T)=0.176e 0.0014T ]]> <![CDATA[δ r,2 mm,k r,2 W / m·K]]> 200,4.1 - - <![CDATA[δ r,3 mm,k r,3 W / m·K]]> 80,0.9

[0122] like Figure 2 Shown is a schematic diagram of slag flow and heat transfer in the gasifier in Example 1. Figure 2 11 is the slag layer; 12 is the fire-facing brick layer; 13 is the backing brick layer; 14 is the insulation brick layer; 15 is the refractory wool layer; 16 is the metal wall; and the radial direction of the furnace body is set to x, and the axial direction of the furnace body is set to z; the solid arrow in the vertical direction represents the flow direction of the slag. Figure 2 It can be seen that the entire heat transfer process is carried out between the liquid slag layer 11, the fire-facing brick layer 12, the backing brick layer 13, the insulation brick layer 14, the refractory wool layer 15, the metal wall 16 and the atmosphere, and the thermal resistance of heat transfer includes the slag layer, refractory brick layer, refractory wool layer, metal wall, and atmospheric convection heat transfer. The high-temperature gas in the furnace transfers heat to the wall through radiation heat transfer and convection heat transfer, and the slag is deposited on the wall to form a liquid liquid slag layer. After the wall absorbs the incoming heat and the heat brought in by the slag deposition, it transfers the heat to the refractory brick layer, refractory wool layer and metal wall in turn based on heat conduction, and finally transfers it to the atmosphere. The temperature rise of the atmosphere is related to parameters such as heat conduction, slag deposition, and slag thickness. Therefore, by measuring the temperature rise of the atmosphere and establishing a wall slag deposition flow and heat transfer model, the thickness of the refractory brick layer δ can be inferred. r,3 .

[0123] The monitoring device for the thickness of the refractory brick layer in this embodiment includes a gasifier and a monitoring module, such as Figure 3The diagram shows the structure of the monitoring module, which includes a calculation module I, a calculation module II and a calculation module III; the calculation module I is used to calculate the thickness of the slag layer through the mass conservation equation of the flow heat transfer process of the liquid slag layer; the calculation module II is used to calculate the heat flux density passing through the metal wall; the calculation module III is used to calculate the thickness of the fire-facing brick layer, the thickness of the backing brick layer and the thickness of the insulation brick layer through the energy conservation calculation established by the heat flux density passing through the metal wall and the heat flux density of "passing through the fire-facing brick layer, passing through the backing brick layer and passing through the insulation brick layer", that is, the thickness of the refractory brick layer; the calculation module I is electrically connected to the calculation module III, and is used to transmit the calculated thickness of the slag layer to the calculation module III; the calculation module II is electrically connected to the calculation module III, and is used to transmit the calculated heat flux density passing through the metal wall to the calculation module III.

[0124] The present embodiment also provides a device for monitoring the temperature of the refractory brick layer, which obtains the temperature of each layer by solving the energy conservation equation between the various layer structures of the gasifier. The device includes a device for monitoring the thickness of the refractory brick layer and a calculation module IV. The calculation module III is electrically connected to the calculation module IV for transmitting the thickness of the refractory brick layer in the calculation module III to the calculation module IV.

[0125] (1) The calculation formula of calculation module I is as follows:

[0126] Assuming that 70wt.% of the slag generated by the gasification reaction of the coal added to the gasifier is deposited on the inner wall of the fire-facing brick layer to form a liquid slag layer, and the distribution is uniform, and the slag flow process satisfies the Newtonian fluid flow, then the mass conservation equation for the slag flow and heat transfer process in the liquid slag layer is established①:

[0127]

[0128] In equation (1), δ s,i It refers to the thickness of the liquid slag layer, in m, and is the first variable to be solved in this embodiment; ρ s is the density of the slag in the liquid slag layer; m in,j is the amount of slag deposited on the wall of the gasifier, in kg, and its value is m in,j = coal quantity entering the furnace × ash content × 70%. Specifically, the dry basis coal quantity entering the gasifier is obtained through a coal slurry or coal powder flow meter, and the slag content in the furnace is calculated in combination with the ash content in the coal; L i is the equivalent circumference of the straight section of the cylinder in the gasifier, in meters, using the formula L = π (D-δ s -x) is calculated, where D is the inner diameter of the gasifier. s -x) is very small relative to D, only 10 times its magnitude -3 , so L iThe calculation formula can be simplified to L i =πD to process; v i (x) is the velocity distribution function in the slag layer, which can be obtained by the momentum equation ②:

[0129] The slag flow velocity equation is:

[0130] The boundary condition of equation ② is

[0131] In equation ②, η s is the dynamic viscosity of the liquid slag layer, v is the velocity of slag flow, g is the gravity acceleration, β is the inclination angle of slag flow on the inner wall of the gasifier, ρ s It refers to the density of the slag in the liquid slag layer, τ is the shear force on the inner wall of the gasifier; η s It is the viscosity distribution in the liquid slag layer, which is the basic physical property data of the slag. It needs to be obtained through analysis and testing. Its value is related to the temperature distribution in the liquid slag layer. It can be obtained through the viscosity-temperature characteristic curve of the slag and the temperature distribution in the liquid slag layer. τ=0.0303ρ g u0 2 ρ g It means that the density of the synthesis gas in the gasifier is calculated according to the type, temperature and pressure of the gasifier, u0 2 Refers to the surface velocity of the liquid slag layer.

[0132] (2) The calculation formula of calculation module II is as follows:

[0133] q out,i =2πΔzr0(T m,i -T air )h air,i ③

[0134] In equation ③, h air is the convective heat transfer coefficient between the outer surface of the metal wall and the atmosphere; it can be calculated according to equation ④:

[0135]

[0136] Among them, T m,i is the temperature of the outer wall of the metal wall, which is measured by setting a wall temperature measuring thermocouple on the outer wall of the metal wall. The thermocouple is an infrared thermometer, such as Figure 5 The figure shows the temperature distribution of the outer surface of the metal wall obtained by real-time measurement, that is, Figure 5 The vertical axis indicates the measured gasifier wall temperature. Figure 5 ( Figure 6 or Figure 7The different curves in ) represent the cumulative usage time of the refractory brick layer of the gasifier. The starting point of time calculation is the beginning of new bricklaying of the refractory brick layer. air is the ambient temperature, measured by setting three ambient temperature thermocouples in the air space outside the metal wall; h conv 2.55W / m 2 K, c are model constants, and their value is 4.06W / m 2 ·K 4 .

[0137] (3) The calculation formula of calculation module III is as follows:

[0138]

[0139] Among them, T g,i is the gas temperature near the inner wall surface in the furnace of the gasifier, measured by the thermocouple in the gasifier, such as Figure 6 The figure shows the gas temperature distribution near the inner wall of the furnace of the gasifier obtained by real-time measurement, that is, Figure 6 The predicted temperature near the wall of the gasifier is marked on the vertical axis;

[0140] r0=r m ,r1=r0-δ m ,r2=r1-δ r,c ,r3=r2-δ r,1 ,r4=r3-δ r,2 ,r5=r4-δ r,3 ,r6=r5-δ s,i ;

[0141] r5 is the inner diameter of the fire-facing brick layer, r6 is the inner diameter of the liquid slag layer, r4 is the inner diameter of the backing brick layer, r3 is the inner diameter of the insulation brick layer, r2 is the inner diameter of the refractory wool layer, r1 is the inner diameter of the metal wall, and r0 is the radius of the gasifier. The radius of the gasifier refers to the distance from the outer wall of the metal wall to the central axis of the gasifier.

[0142] k m , k r,c , k r,1 ,k r,2 ,k r,3 ,k s,i They are the thermal conductivity of the metal wall, the thermal conductivity of the refractory wool layer, the thermal conductivity of the insulation brick layer, the thermal conductivity of the backing brick layer, the thermal conductivity of the fire-facing brick layer and the thermal conductivity of the liquid slag layer, which are obtained by querying the physical property parameters. r,1 =k r,c , k r,0 =k m ;

[0143] δ m, δ r,c , δ r,1 ,δ r,2 ,δ r,3 , and δ s,i They are the thickness of the metal wall, the thickness of the refractory wool layer, the thickness of the insulation brick layer, the thickness of the backing brick layer, the thickness of the fire-facing brick layer and the thickness of the liquid slag layer. The thicknesses of the metal wall, the refractory wool layer, the insulation brick layer and the backing brick layer are constant values.

[0144] By solving equations ① to ⑤ together, the thickness of the insulating brick layer, the backing brick layer and the fire-facing brick layer can be calculated based on the outer wall temperature of the metal wall, the ambient temperature, the gas temperature near the inner wall in the furnace of the gasifier, the ash content and flow rate in the coal, the structural parameters and physical properties of the gasifier. The thickness of the refractory brick layer can be obtained by summing them up.

[0145] (4) The temperature of the refractory brick layer is calculated using the energy conservation equation.

[0146] From the above analysis, it can be seen that the heat transfer from the gasifier to the atmosphere (i.e., the heat loss of the outer wall surface of the metal wall of the gasifier) ​​is related to the gasifier temperature and the thickness of the liquid slag layer; the thickness of the liquid slag layer is related to the slag deposition amount on the one hand, and the temperature distribution in the liquid slag layer on the other hand.

[0147] Therefore, the temperature of the refractory brick layer can be calculated by substituting the thickness of the refractory brick layer calculated above into the following equation:

[0148] q out,i ×A m =q refc ×A rc =q ref1 ×A r1 =q ref2 ×A r2 =q ref3 ×A r3 =q refs ×A s ⑥

[0149] In equation ⑥, q out,i ,q refc ,q ref1 ,q ref2 ,q ref3 ,q refs A refers to the heat flux density passing through the metal wall, refractory wool layer, insulation brick layer, backing brick layer, fire facing brick and liquid slag layer respectively; m , A rc , A r1 , A r2 , A r3 , A sThey refer to the radial heat transfer areas of the metal wall, refractory wool layer, insulation brick layer, backing brick layer, fire-facing brick layer and liquid slag layer respectively.

[0150] like Figure 4 The figure shows the calculation principle flow chart of this embodiment. This embodiment measures and calculates the temperature of the outer wall of the metal wall, the temperature of the furnace in the gasifier, the velocity parameter of the slag flow and the thickness of the liquid slag layer, and respectively establishes the flow equation and the heat balance equation for the slag flow and heat transfer process, and uses the iteration method to solve the thickness of the refractory brick layer. Figure 7 The figure shows the thickness of the fire-facing brick layer measured in real time in this embodiment. It can be seen from the figure that the method of this embodiment can measure the thickness of the fire-facing brick layer in real time and accurately, and then obtain the thickness of the refractory brick layer in real time.

[0151] The monitoring device also includes a measuring component and a computing terminal. The measuring component includes a flow meter and an ash meter for measuring the amount of slag, which respectively measure the dry basis coal amount in the gasifier and the ash content in the coal. The measuring component also includes a plurality of temperature measuring components for measuring the temperature T of the outer wall surface of the metal wall. m,i 、Ambient temperature T air and the gas temperature T near the inner wall of the furnace of the gasifier g,i .

[0152] The calculation terminal is a computer or programmable controller, which measures the outer surface temperature T of the coal slurry or coal powder flow and the metal wall measured by the instrument. m,i 、Ambient temperature T air , the gas temperature near the inner wall of the gasifier furnace T g,i The data are transmitted to the computing terminal; equations ① to ⑥ are calculated on the terminal to obtain the temperature and thickness of the refractory brick layer in the gasifier in real time online.

Claims

1. A device for monitoring the thickness of a refractory brick layer, characterized in that: It includes a measuring component connected to the furnace body to be monitored, and the monitoring device also includes a calculation module I, a calculation module II and a calculation module III; The measuring component is used to measure the parameters required by the calculation module I, the calculation module II and the calculation module III when running calculations; The furnace body to be monitored is a gasification furnace, which includes a liquid slag layer, a refractory brick layer and a metal wall from the inside to the outside, and the refractory brick layer includes a fire-facing brick layer, a backing brick layer and an insulating brick layer from the inside to the outside; the calculation module I is used to calculate the thickness of the liquid slag layer through the mass conservation equation of the flow heat transfer process of the liquid slag layer; The calculation formula of the calculation module I is as follows: 70wt.% of the coal added to the gasifier after gasification reaction is deposited on the inner wall of the fire-facing brick layer to form the liquid slag layer, and is evenly distributed. The slag flow in the liquid slag layer satisfies the Newtonian fluid flow. The mass conservation calculation formula established for the flow heat transfer process of the liquid slag layer is shown in equation ①: In equation ①, δ s,i It refers to the thickness of the liquid slag layer, in m; ρ s is the density of the slag in the liquid slag layer; m in,j is the amount of slag deposited on the inner wall of the gasifier, in kg / s, and its value is m in,j = coal quantity × ash content × 70%; L i is the equivalent circumference of the straight section of the cylinder in the gasifier, in m; x is the displacement of the particle in the liquid slag layer; i is the coordinate identifier of the position of the point, j is the coordinate range from the top of the gasifier to the i-th point, and the physical meaning is that the amount of slag at the i-th point is the sum of all deposited particles from the top to the i-th point; v i (x) is the velocity distribution function in the liquid slag layer, which is obtained by the momentum equation ②: ②, the boundary condition of equation ② is In equation ②, η s is the dynamic viscosity of the liquid slag layer, v is the velocity of slag flow, g is the gravitational acceleration, β is the inclination angle of slag flowing on the inner wall of the gasifier, ρ s It refers to the density of slag in the liquid slag layer, τ is the shear force on the inner wall of the gasifier; The calculation module II is used to calculate the heat flux density passing through the metal wall; The calculation formula of the calculation module II is as follows: q out,i =2πΔzr0(T m,i -T air )h air,i ③ T m,i is the temperature of the outer wall of the metal wall, T air is the ambient temperature, h air,i is the convection heat transfer coefficient between the outer wall of the metal wall and the atmosphere, △z is the height of the fire-facing brick layer, r0 is the radius of the gasifier, and the radius of the gasifier refers to the distance from the outer wall of the metal wall to the central axis of the gasifier; In equation ③, h air According to formula ④, it is calculated as follows: In equation ④, h conv is the natural convection constant, c is the constant of the metal wall; The calculation module III is used to substitute the heat flux density passing through the metal wall and the thickness of the liquid slag layer into the heat flux density equation of "passing through the fire-facing brick layer, passing through the backing brick layer and passing through the insulation brick layer" established based on the law of energy conservation, and obtain the thickness of the fire-facing brick layer, the thickness of the backing brick layer and the thickness of the insulation brick layer respectively. The sum of the thickness of the fire-facing brick layer, the thickness of the backing brick layer and the thickness of the insulation brick layer is the thickness of the refractory brick layer; In the calculation module III, the calculation formula is as follows: In equation ⑤, q ref,i =q out,i , T g,i is the gas temperature near the inner wall surface in the furnace of the gasifier; r3=r2-δ r,1 ,r4=r3-δ r,2 ,r5=r4-δ r,3 ,r6=r5-δ s,i ; r5 is the inner diameter of the fire-facing brick layer, r6 is the inner diameter of the liquid slag layer, r4 is the inner diameter of the backing brick layer, and r3 is the inner diameter of the insulation brick layer; k r,1 ,k r,2 ,k r,3 ,k s,i The thermal conductivity of the insulating brick layer, the thermal conductivity of the backing brick layer, the thermal conductivity of the fire-facing brick layer and the thermal conductivity of the liquid slag layer are obtained by querying the physical property parameters; δ r,1 ,δ r,2 ,δ r,3 and δ s,i are respectively the thickness of the heat-insulating brick layer, the thickness of the backing brick layer, the thickness of the fire-facing brick layer and the thickness of the liquid slag layer; The calculation module I is electrically connected to the calculation module III for transmitting the calculated thickness of the liquid slag layer to the calculation module III; the calculation module II is electrically connected to the calculation module III for transmitting the calculated heat flux density passing through the metal wall to the calculation module III.

2. The device for monitoring the thickness of the refractory brick layer according to claim 1, characterized in that: ρ s 2500kg / m 3 .

3. The device for monitoring the thickness of the refractory brick layer according to claim 1, characterized in that: τ=0.0303ρ g u0 2 ; ρ g It refers to the density of the synthesis gas in the gasifier, u0 2 It refers to the surface velocity of the liquid slag layer.

4. The device for monitoring the thickness of the refractory brick layer according to claim 1, characterized in that: η s It is determined by the viscosity-temperature characteristic curve of the slag and the temperature distribution in the liquid slag layer.

5. The device for monitoring the thickness of the refractory brick layer according to claim 1, characterized in that: h conv Calculated by the following equation ④-1: In equation ④-1, L is the height of the straight section of the cylinder in the gasifier.

6. The device for monitoring the thickness of the refractory brick layer according to claim 5, characterized in that: The h conv 2.55W / m 2 ·K.

7. The device for monitoring the thickness of the refractory brick layer according to claim 5, characterized in that: The c in equation ④ is 4.06W / m 2 ·K 4 .

8. The device for monitoring the thickness of the refractory brick layer according to claim 7, characterized in that: The measuring component includes a flow meter and an ash meter, and the flow meter is a coal slurry flow meter or a coal powder flow meter; And / or, the measuring component includes temperature measuring component 1, temperature measuring component 2 and temperature measuring component 3; The temperature measuring component 1 is used to measure the temperature T of the outer wall surface of the metal wall m,i ; The temperature measuring component 2 is used to measure the ambient temperature T of the outer wall surface close to the metal wall. air ; The temperature measuring component 3 is used to measure the gas temperature T near the inner wall surface in the furnace of the gasifier. g,i ; And / or, a refractory wool layer is further included between the insulation brick layer and the metal wall; the monitoring device further includes calculating the thickness of the refractory wool layer and the metal wall by substituting the following formula into equation ⑤: r0=r m ,r1=r0-δ m ,r2=r1-δ r,c , wherein r2 is the inner diameter of the refractory wool layer, r1 is the inner diameter of the metal wall, and r0 is the radius of the gasifier; k m , k r,c are the thermal conductivity of the metal wall and the thermal conductivity of the refractory wool layer, respectively, which are obtained by querying the physical property parameters, where k r,1 =k r,c , k r,0 =k m ; δ m , δ r,c They are respectively the thickness of the metal wall and the thickness of the refractory wool layer.

9. The device for monitoring the thickness of the refractory brick layer according to claim 8, characterized in that: The temperature measuring component 1, the temperature measuring component 2 or the temperature measuring component 3 is a thermocouple.

10. The device for monitoring the thickness of the refractory brick layer according to claim 9, characterized in that: The thermocouple is an infrared thermometer.

11. A device for monitoring the temperature of a refractory brick layer, characterized in that: It comprises a monitoring device for the thickness of the refractory brick layer as claimed in any one of claims 1 to 10 and a calculation module IV, wherein the calculation module IV is used to establish the energy conservation equation as described below: q out，i ×A m =q ref,1 ×A r1 =q ref,2 ×A r2 =q ref,3 ×A r3 =q ref,s ×A s ⑥ In equation ⑥, q out,i ,q ref,1 ,q ref,2 ,q ref,3 ,q ref,s A refers to the heat flux density passing through the metal wall, the heat flux density of the insulation brick layer, the heat flux density of the backing brick layer, the heat flux density of the fire facing bricks and the heat flux density of the liquid slag layer respectively; m , A r1 , A r2 , A r3 , A s They respectively refer to the radial heat transfer area of ​​the metal wall, the radial heat transfer area of ​​the insulation brick layer, the radial heat transfer area of ​​the backing brick layer, the radial heat transfer area of ​​the fire-facing brick layer and the radial heat transfer area of ​​the liquid slag layer; The calculation module III is electrically connected to the calculation module IV, and is used to transmit the thickness of the refractory brick layer in the calculation module III to the calculation module IV.

12. A method for monitoring the thickness of a refractory brick layer, characterized in that: The method comprises the following steps: the heat transfer process of the gasifier is carried out from the inside to the outside in sequence between the liquid slag layer, the refractory brick layer, the metal wall and the atmosphere; The refractory brick layer includes a fire-facing brick layer, a backing brick layer and a heat-insulating brick layer from the inside to the outside; The steps for calculating the thickness of the refractory brick layer are as follows: Step (1), 70wt.% of the coal added to the gasifier is deposited on the inner wall of the fire-facing brick layer to form the liquid slag layer, and the distribution is uniform. The slag flow in the liquid slag layer satisfies the Newtonian fluid flow. The mass conservation equation ① is established for the flow and heat transfer process of the liquid slag layer, and the thickness of the liquid slag layer is obtained: In equation ①, δ s,i It refers to the thickness of the liquid slag layer, in m; ρ s is the density of the slag in the liquid slag layer; m in,j is the amount of slag deposited on the inner wall of the gasifier, in kg, and its value is m in,j = coal quantity × ash content × 70%; L i is the equivalent circumference of the straight section of the cylinder in the gasifier, in m; x is the displacement of the particle in the liquid slag layer; v i (x) is the velocity distribution function in the liquid slag layer, which is obtained by the momentum equation ②: The boundary condition of equation ② is In equation ②, η s is the dynamic viscosity of the liquid slag layer, v is the velocity of slag flow, g is the gravitational acceleration, β is the inclination angle of slag flowing on the inner wall surface of the gasifier, ρ s It refers to the density of the slag in the liquid slag layer, τ is the shear force on the inner wall of the gasifier; Step (2), calculating the heat flux density passing through the metal wall: T m,i is the temperature of the outer wall of the metal wall, T air is the ambient temperature, h air,i is the convection heat transfer coefficient between the outer wall of the metal wall and the atmosphere, △z is the height of the brick layer facing the fire; In equation ③, h air According to formula ④, it is calculated as follows: In equation ④, h conv is the natural convection constant, c is the constant of the metal wall; Step (3): convert the q calculated in step (2) into out,i Substitute into equation ⑤, and q ref,i =q out,i , calculate r j : Among them, T g,i is the gas temperature near the inner wall surface in the furnace of the gasifier; According to equation ⑤, r j Substitute into the following formula to calculate the thickness of each layer: r2=r1-δ r,c ,r3=r2-δ r,1 ,r4=r3-δ r,2 ,r5=r4-δ r,3 ,r6=r5-δ s,i ; r5 is the inner diameter of the fire-facing brick layer, r6 is the inner diameter of the liquid slag layer, r4 is the inner diameter of the backing brick layer, and r3 is the inner diameter of the insulation brick layer; k r,1 ,k r,2 ,k r,3 ,k s,i The thermal conductivity of the insulating brick layer, the thermal conductivity of the backing brick layer, the thermal conductivity of the fire-facing brick layer and the thermal conductivity of the liquid slag layer are obtained by querying the physical property parameters; δ r,1 ,δ r,2 ,δ r,3 and δ s,i are respectively the thickness of the heat-insulating brick layer, the thickness of the backing brick layer, the thickness of the fire-facing brick layer and the thickness of the liquid slag layer; Solve equations ①~⑤ together to find δ r,1 ,δ r,2 and δ r,3 , and the sum of them can be used to calculate the thickness of the refractory brick layer.

13. The method for monitoring the thickness of a refractory brick layer according to claim 12, characterized in that: The temperature of the slag in the liquid slag layer is above 1300°C; and / or, s The value is 2500kg / m 3 ; and / or, τ = 0.0303ρ g u0 2 ; ρ g It refers to the density of the synthesis gas in the gasifier, u0 2 refers to the surface velocity of the liquid slag layer; and / or, s It is determined by the viscosity-temperature characteristic curve of the slag and the temperature distribution in the liquid slag layer.

14. The method for monitoring the thickness of a refractory brick layer according to claim 12, characterized in that: T m,i The temperature is measured by a thermocouple arranged on the outer wall surface of the metal wall of the gasifier; the thermocouple adopts an infrared thermometer; And / or, in equation ③ and equation ④, T air By setting a plurality of ambient temperature thermocouples on the outer wall surface of the metal wall, when calculating the heat flux, it is calculated according to the natural convection heat transfer; and / or, h in equation ④ conv The value is taken and corrected according to the actual situation on site, and calculated by the following equation ④-1: In equation ④-1, L is the height of the straight section of the cylinder in the gasifier; And / or, equation ④, the c is 4.06W / m 2 ·K 4 ; And / or, a refractory wool layer is further included between the metal wall and the insulation brick layer, and the monitoring method further includes calculating the thickness of the refractory wool layer by substituting the following formula into equation ⑤: r0=r m ,r1=r0-δ m ,r2=r1-δ r,c , wherein r2 is the inner diameter of the refractory wool layer, r1 is the inner diameter of the metal wall, and r0 is the radius of the gasifier, and the radius of the gasifier refers to the distance from the outer wall surface of the metal wall to the central axis of the gasifier; k m , k r,c are the thermal conductivity of the metal wall and the thermal conductivity of the refractory wool layer, respectively, which are obtained by querying the physical property parameters, where k r,1 =k r,c , k r,0 =k m ; δ m , δ r,c They are respectively the thickness of the metal wall and the thickness of the refractory wool layer.

15. The method for monitoring the thickness of a refractory brick layer according to claim 14, characterized in that: The number of the ambient temperature thermocouples is 2 to 6.

16. The method for monitoring the thickness of a refractory brick layer according to claim 14, characterized in that: The number of the ambient temperature thermocouples is 3.

17. The method for monitoring the thickness of a refractory brick layer according to claim 14, characterized in that: The h conv 2.55W / m 2 ·K.

18. A method for monitoring the temperature of a refractory brick layer, characterized in that: The thickness of the refractory brick layer calculated according to the monitoring method for the thickness of the refractory brick layer according to any one of claims 12 to 17 is used to establish the energy conservation equation shown below to obtain the temperature of the refractory brick layer: q out，i ×A m =q ref,1 ×A r1 =q ref,2 ×A r2 =q ref,3 ×A r3 =q ref,s ×A s ⑥ q out,i ,q ref,1 ,q ref,2 ,q ref,3 ,q ref,s A refers to the heat flux density passing through the metal wall, the insulating brick layer, the backing brick layer, the fire-facing bricks and the liquid slag layer respectively; m , A r1 , A r2 , A r3 , A s They respectively refer to the radial heat transfer area of ​​the metal wall, the radial heat transfer area of ​​the insulating brick layer, the radial heat transfer area of ​​the backing brick layer, the radial heat transfer area of ​​the fire surface brick layer and the radial heat transfer area of ​​the liquid slag layer, that is, the temperature of the refractory brick layer.

19. The method for monitoring the temperature of a refractory brick layer according to claim 18, characterized in that: A refractory wool layer is included between the metal wall and the insulation brick layer. The temperature of the refractory wool layer is determined by q out,i ×A m =q refc ×A rc The equation is calculated, q refc Refers to the heat flux density passing through the refractory wool layer, A rc It refers to the radial heat transfer area of ​​the refractory wool layer.

Images