A prediction method for hydrogen halide in a high-temperature gasifier of multi-component organic waste

Abstract

The present invention relates to a method for predicting hydrogen halide in a high-temperature gasification furnace for multi-component organic waste. In view of the limitations of the traditional numerical simulation method of the gasifier, the method first performs physical modeling and meshes it, and then uses Fluent software to perform numerical simulation. In combination with the properties of multi-component organic waste and the characteristics of the gasification process, Finite‑Rate / Eddy‑Dissipation in the component transport model is selected as the combustion model, and the gasification process of the multi-component organic waste is reasonably simplified. Finally, the distribution cloud map of the amount of hydrogen halide gas generated in the gasifier is obtained through the post-processing of CFD‑Post, and the numerical distribution laws of indicators such as synthesis gas and temperature are also obtained. The present invention successfully simulates the reaction process in the high-temperature gasification furnace of multi-component organic waste by selecting a suitable model and reasonable assumptions. The prediction error of synthesis gas is within 2%, and the distribution law of hydrogen halide in the furnace that is difficult to measure in practice is obtained.

Description

Technical Field

[0001] The invention belongs to the fields of energy industry and chemical engineering, and in particular is a method for predicting hydrogen halide in a high-temperature gasification furnace of multi-component organic waste. Background Art

[0002] High-temperature gasification and melting furnaces mainly include Shell, GSP, Prenflo, Eagle and other gasifiers for dry coal powder feeding and Texaco, E-GAS, multi-nozzle opposed type and other gasifiers for water-coal slurry feeding, which mainly produce synthetic ammonia and CO, H 2 and other chemical products. In the traditional water-coal slurry gasification process, due to the low halogen content in coal, there are few predictive studies on the production of hydrogen halides. In recent years, the use of organic waste to replace part of the coal as the feed of the gasifier has become a research hotspot. On the one hand, it can achieve the harmless disposal and resource utilization of organic waste, and on the other hand, it also reduces the consumption of fossil fuels and achieves carbon emission reduction. Industrial organic waste mainly includes solid wastes such as distillation residues, waste activated carbon, waste catalysts, industrial sludge, waste tires, and waste printed circuit boards, and liquid wastes such as waste organic solvents and waste mineral oils. Because multi-component industrial organic waste contains organic halogen compounds such as organic fluorine and organic chlorine, as well as inorganic salts such as sodium fluoride and sodium chloride, its halogen content is usually dozens of times more than that of water-coal slurry. In the gasifier, the traditional water-coal slurry undergoes pyrolysis and gasification under high temperature conditions to generate CO, CO 2 , H 2 The main syngas is the inorganic matter, which will melt and solidify into glassy slag. The hydrogen halide produced by high-temperature gasification will cause acid corrosion to the refractory materials in the gasifier, thereby reducing the service life of the gasifier.

[0003] Since multi-component organic waste has the characteristics of high halogen content and contains a large amount of low-boiling, volatile and unstable organic matter, it will inevitably lose its organic matter quality and composition after drying at a certain temperature, so it is impossible to conduct conventional and accurate full element analysis and industrial analysis. In the actual production process, due to the large differences in the raw materials entering the furnace, the existing technology cannot accurately predict the generation and distribution of hydrogen halide gas in the furnace. Therefore, it is extremely important to explore a prediction method suitable for hydrogen halide gas in a high-temperature melting gasification furnace. The paper (Feng Yuheng, Research on the precipitation and removal mechanism of fluorine and chlorine gases during combustion and pyrolysis of hazardous chemical waste [D], Zhejiang University, 2014: 17-18) used TG-FTIR technology to conduct an experimental analysis of the thermal decomposition of hydrogen fluoride and hydrogen chloride gases from waste slag in the production of potassium dihydrogen phosphate. The release of hydrogen halide gas during the combustion of organic waste needs to be tested in a laboratory. The existing process focuses on the incinerator of organic hazardous waste, and lacks research on the release of hydrogen halide gas in the gasifier. The temperature in the gasifier is as high as 2000°C and the material residence time is less than 5s. The existing laboratory technology cannot measure the generation of hydrogen halide gas. In summary, neither factory field sampling nor laboratory tests can measure the hydrogen halide gas in the multi-component organic hazardous waste gasifier.

[0004] Computer simulation is also called numerical simulation. Generally speaking, it refers to using computers to conduct experiments and using computers as computing platforms to solve some engineering problems, physical problems, etc. The numerical simulation method can provide furnace temperature, pressure, product concentration, etc., which facilitates experimental research and industrial operation of gasifiers. The paper (Luan YT, Chyou YP, Wang T. Numerical analysis of gasification performance via finite-rate model in a cross-type two-stage gasifier [J]. International Journal of Heat & Mass Transfer, 2013, 57 (2): 558-566.) uses the Euler-Lagrange method to perform numerical simulation on a three-dimensional E-GAS water-coal slurry gasifier, mainly investigating the influence of the oxygen-coal ratio on the outlet synthesis gas temperature and the CO content in the synthesis gas. In CN105930585A, the inventors used the non-premixed combustion method in Fluent to complete the simulation of the flow field and temperature field of the Shell gasifier, providing complete data for the main synthesis gas in the Shell gasifier. The feed composition of the existing gasifier numerical simulation is coal or water-coal slurry.

[0005] The difficulty of predicting the hydrogen halide gas in the multi-component organic waste gasifier targeted by the present invention is:

[0006] (1) The system reaction with multi-component organic waste as feed is more complicated, and the components of multi-component organic waste include distillation residues, antibiotic residues, organic solvents and other organic wastes. The halogen content and type of the feed vary with the source of the organic waste, so it is necessary to explore a prediction method with wide applicability.

[0007] (2) The sources of multi-component organic waste are complex. How to reasonably simplify the model of the gasification process of multi-component organic waste so that the complex and changeable reactions can be summarized in a simple form?

[0008] (3) Traditional non-premixed combustion model: This model uses a probability density function model to solve, avoiding specific chemical reactions. It is no longer applicable to gasifier systems that need to determine the value of hydrogen halide, because halogen-containing materials cannot be added to the non-premixed combustion model, resulting in limitations in the method.

[0009] (4) The non-premixed combustion model is suitable for the finite rate chemical reaction model, while the combustion in the gasifier should be a rapid chemical reaction. The present invention selects the Finite-Rate / Eddy-Dissipation model in the component transport model. This model is selected as the finite rate chemical reaction model Finite-Rate at the initial stage of ignition, and the rapid chemical reaction model Eddy-Dissipation after stable combustion. The present invention is closer to the actual reaction process.

[0010] (5) Existing simulations of gasifiers mainly focus on synthesis gases such as CO, H 2 ,CO 2 ,N 2 The multi-component organic hazardous waste gasification process involved in the present invention has a high content of halogen elements. Compared with other gasifier simulation methods, the present invention focuses more on the prediction of hydrogen halide gas.

[0011] Through searching the prior art, no research was found on the gasification process using multi-component organic waste as raw material. When coal is used as the raw material for the gasification process, the precipitation of halogens is negligible. Compared with coal, multi-component organic waste has the characteristic of high halogen content, so it is necessary to measure the hydrogen halide gas produced by the halogen reaction. The existing technology can measure the value of the synthesis gas of the gasifier reaction, but it cannot measure the value of the hydrogen halide gas in the furnace. The existing gasifier simulation method is limited to the simulation of the synthesis gas of the gasifier, and lacks research on the simulation of hydrogen halide in the gasification process. Summary of the invention

[0012] In view of the above research background, the present invention provides a method for predicting hydrogen halide gas in a high-temperature gasifier for multi-component organic waste. The present invention comprises the following steps:

[0013] Step 1, measuring and collecting data during the operation of an actual multi-component organic waste high-temperature gasification furnace, wherein the measured data include the halogen content in the multi-component organic waste and the proportion of synthesis gas at the outlet of the gasifier, and the collected data include the size of the gasifier, the size of the gasifier nozzle, the pressure in the gasifier, the slurry flow rate, the oxygen flow rate, and the furnace wall temperature;

[0014] Step 2, using the gasifier size and nozzle size information collected in step 1 to establish a gasifier geometric model, divide the geometric model into structured grids and determine the calculation area;

[0015] Step 3, making assumptions about the high-temperature melt gasifier, simplifying the gasification reaction process of the multi-component organic waste into the reaction of the main average organic matter and the reaction of the halogen-containing organic matter; using the synthesis gas ratio measured in step 1 to infer the molecular weight of the main average organic matter; using the type of halogen in the multi-component organic waste measured in step 1 to determine the type of halogen selected for simulation;

[0016] Step 4, import the model of step 2 into Fluent, select the turbulence model, radiation model, energy model, discrete phase model and component transport model in the calculation model and set the calculation model parameters, set the chemical reaction equation and the molecular weight of the main average organic matter and halogen-containing organic matter assumed in step 3, and set the boundary conditions and solver;

[0017] Step 5, post-processing the data obtained after the Fluent calculation is completed to obtain a distribution cloud map of hydrogen halide in the gasifier.

[0018] As a preferred embodiment of the present invention, in step 1, the halogen content in the multi-component organic waste includes the content of fluorine, chlorine, bromine and iodine; the halogen content needs to be sampled multiple times to take the average value, and the synthesis gas needs to correspond one-to-one with the multi-component organic hazardous waste, and multiple samples need to be sampled to take the average value.

[0019] As a preferred embodiment of the present invention, in step 2, the specific steps for establishing the geometric model of the gasifier are: according to the structure and size of the high-temperature melting gasifier, the geometric model of the high-temperature melting gasifier is established in combination with the nozzle structure and taking into account the actual production situation; since the high-temperature melting gasifier is a central axis symmetrical structure, the geometric model is simplified to 1 / 4 of the whole for subsequent meshing.

[0020] As a preferred solution of the present invention, in step 2, the geometric model is structured meshed and the calculation area is determined. The specific steps are as follows:

[0021] 2.1) Select the furnace area of ​​the built 1 / 4 gasifier geometric model as the calculation area;

[0022] 2.2) Divide the computational domain into hexahedral structured grids to form an overall symmetrically distributed hexahedral structured grid, examine the grid quality and the number of grids, determine the number of grid nodes, and obtain a high-quality hexahedral structured grid;

[0023] 2.3) Define the solution domain, name the boundary conditions of the gasifier surface, and save the file.

[0024] As a preferred embodiment of the present invention, in step 2.3, the interior of the gasifier, the nozzle inlet plane and the gasifier outlet plane are defined as the solution domain; the naming of the boundary conditions of the gasifier surface is specifically: the nozzle inlet is named as the inlet, the gasifier outlet is named as the outlet, and the gasifier furnace wall is named as the wall.

[0025] As a preferred embodiment of the present invention, in step 3, the assumptions made for the gasifier include:

[0026] 3.1) Only the combustion process of combustible components is considered in the gasifier, and the influence of ash is not considered;

[0027] 3.2) The combustible components are simplified to the main average burning organic matter without halogen and the organic matter containing halogen;

[0028] 3.3) The main average combustion organic matter without halogen is expressed as hv_vol;

[0029] 3.4) Halogen-containing organic compounds are simplified to CH 2 X 2 ; Wherein X is selected from the halogen fluorine, chlorine, bromine, iodine, CH 2 X 2 The mass fraction of the assumed combustible component is obtained by converting the mass fraction of the halogen in the multi-component organic waste measured in step 1;

[0030] 3.5) The initial velocity and flow rate of fuel and oxidant are constant;

[0031] 3.6) The combustion gas products are simplified to CO, CO 2 , H 2 , H 2 O and HX.

[0032] As a preferred embodiment of the present invention, the specific steps of step 4 are as follows:

[0033] 4.1) Import the model in step 2 into Fluent;

[0034] 4.2) Select the steady-state solver based on pressure basis, select the turbulence model, radiation model, energy model, discrete phase model and component transport model in the calculation model and set the calculation model parameters. Among them, the component transport model selects the Finite-Rate / Eddy-Dissipation model

[0035] 4.3) Select the coal-hv-volatiles-air mixed material in the component transport model and add CH according to the actual situation of the factory. 2 X 2 , CO, H 2 , HX material and set material properties;

[0036] 4.4) The combustion reaction is simplified to the combustion of the main average organic matter without halogen and the organic matter containing halogen. The specific chemical reaction formula is:

[0037] hv_vol+2O 2 =aCO+bH 2 +cCO 2 +dH 2 O

[0038] CH 2 X 2 +O 2 =CO 2 +2HX

[0039] The values ​​of a, b, c, and d are the ratio coefficients of the synthesis gas CO and H measured in step 1. 2 , CO 2 , H 2 O ratio is calculated;

[0040] 4.5) Set the discrete phase injection source type to surface, the pyrolysis component is the assumed halogen-free main average combustion organic matter hv_vol, and modify the molecular weight of hv_vol;

[0041] 4.6) Set the boundary conditions of the physical model in Fluent according to the gasifier slurry flow, gasifier pressure, gasifier oxygen flow, gasifier inlet temperature, gasifier outlet temperature, and furnace wall temperature collected in step 1;

[0042] 4.7) After initialization, perform iterative calculations to obtain calculation result data.

[0043] As a preferred embodiment of the present invention, the halogen-free main average combustion organic matter hv_vol represents the mixed material, and the specific molecular weight of hv_vol is obtained based on the actual synthesis gas ratio and the chemical reaction formula specified above, and the molecular weight of hv_vol is modified in step 4.5).

[0044] As a preferred solution of the present invention, in step 4, the specific steps for setting boundary conditions for Fluent are: according to the gasifier slurry flow, gasifier pressure, gasifier oxygen flow, gasifier inlet temperature, gasifier outlet temperature, and furnace wall temperature collected in step 1, the boundary conditions of the physical model in Fluent are set to perform boundary constraints.

[0045] As a preferred embodiment of the present invention, in step 5, the post-processing method includes: outputting the Fluent simulation results as graphics or curves, and displaying the distribution of hydrogen halide gas, the distribution of synthesis gas and the distribution of temperature in the high-temperature melt gasifier through distribution cloud maps and data maps after post-processing.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) Multi-component organic wastes usually contain high levels of halogen elements. In the multi-component organic waste gasification process, the generation of hydrogen halide gas in the gasifier will cause serious corrosion to the furnace wall. However, existing methods cannot directly measure the generation of hydrogen halide gas in the gasifier. The present invention uses a numerical simulation method to provide a method flow of physical model, grid division, numerical simulation, and result post-processing, and successfully simulates the distribution and value of hydrogen halide gas that is difficult to measure in the multi-component organic waste gasification process, providing a theoretical basis for the production of multi-component organic waste gasification process, and providing a numerical basis for evaluating the corrosion of hydrogen halide to the gasifier wall, which is suitable for industrial application.

[0048] (2) The reaction of multi-component organic waste in the gasifier is complex. This paper reasonably simplifies the reaction of multi-component organic waste in the gasifier, simplifies the main reaction in the gasifier into a special combustion reaction of average organic matter, and selects the average organic matter as the hv_vol material in Fluent. It is not necessary to know its specific chemical formula. The molecular weight of the average organic matter can be obtained by using the chemical reaction formula using the actual measurable gasifier synthesis gas information. The secondary reaction is simplified to a combustion reaction of a main halogen-containing organic matter, and the main halogen-containing organic matter is represented by CH 2 X 2 Where X represents halogen, and its value is determined by the type of halogen measured in multi-component organic waste. This paper makes it possible to model the multi-component organic waste gasification process, which is difficult to model due to too many reactions, through reasonable simplification. The specific parameters used are all common parameters in the gasification furnace process, and the prediction of hydrogen halide gas in the multi-component organic waste gasifier is achieved in the simplest way.

[0049] (3) The SpaceClam software used in the gasifier modeling process of the present invention is suitable for axisymmetric models, making the physical modeling of the gasifier simpler and faster. The combustion model Finite-Rate / Eddy-Dissipation in Fluent used in the present invention can realize the autonomous modification of chemical reactions, so that the simplified content can be specifically implemented. Although the actual reaction of the multi-component organic waste gasification process is simplified, the main products of the gasifier, the synthesis gas CO and H 2 , CO 2 , H 2 The error between the predicted value and the actual value of O is within 2%, which verifies the accuracy of the simulation method. The present invention provides a simple, fast and industrially feasible method for predicting hydrogen halide in a high-temperature gasifier of multi-component organic waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is the physical structure model diagram of the high temperature gasifier;

[0051] Figure 2 Flowchart for ICEM CFD meshing;

[0052] Figure 3 Schematic diagram of structured grid division;

[0053] Figure 4 Set up a flowchart for Fluent;

[0054] Figure 5 It is the velocity vector diagram of the vertical section of the gasifier;

[0055] Figure 6 It is the temperature cloud diagram of the vertical section of the gasifier;

[0056] Figure 7 This is the CO molar mass cloud diagram of the vertical section of the gasifier;

[0057] Figure 8 H is the vertical section of the gasifier 2 Molar mass cloud diagram;

[0058] Fig. 9 Comparison chart of simulated value and actual value of syngas at gasifier outlet;

[0059] Fig.10 This is the molar mass cloud diagram of HCl in the vertical section of the gasifier. DETAILED DESCRIPTION

[0060] The present invention can provide a new method for predicting hydrogen halide gas in a high-temperature gasification furnace of multi-component organic waste, provide a basis for preventing and controlling hydrogen halide gas corrosion in industrial production, and provide a reference for the material proportioning of multi-component organic waste.

[0061] The present invention is further described below with reference to examples and drawings.

[0062] The example selected a multi-component organic waste high-temperature gasifier in a domestic factory. This factory mainly uses multi-component organic hazardous waste to produce clean energy such as hydrogen by cooperating with water-coal slurry gasification technology. The main halogen element contained in the material is Cl, which mainly produces HCl to corrode refractory bricks. The example shows the simulation of the distribution of HCl gas in this high-temperature melting gasifier. First, according to the actual size of the factory gasifier, the same physical model is established using SpaceClaim software, and according to the symmetry of the high-temperature melting gasifier, a 1 / 4 model is selected for subsequent modeling; ICEM CFD is used to divide the hexahedral structured grid and verify the grid quality and grid number, determine the number of nodes of the grid, and name the boundary conditions of the gasifier surface; and make reasonable assumptions about the gasifier to simplify the model; according to the characteristics of the high-temperature melting gasifier and the actual production situation of the factory, set appropriate control equations, model parameters and boundary conditions, set solver parameters, discretize the control equations and boundary conditions, calculate the initialization setting number of iterations, and solve the model. Finally, the Fluent simulation results are output as graphs or curves and post-processed using CFD-Post software. After post-processing, the distribution of HCl gas in the high-temperature melt gasifier and other basic physical quantities such as temperature synthesis gas can be intuitively understood through the data graph.

[0063] See also Figure 1 This paper takes a domestic Texaco high-temperature gasification melting furnace as an example. The furnace is 7300mm high and the inner diameter of the furnace body is 1430mm. The material water-coal slurry is mixed with oxygen and then sprayed out from the nozzle. The depth of the nozzle inserted into the furnace top is 800mm, and the inner diameter of the outlet is 400mm. The present invention uses Spaceclaim software to perform physical modeling of the gasification melting furnace. Figure 1 As shown in its vertical cross-section sketch, the gasifier inlet is composed of three concentric circles. The central inlet is the central oxygen channel, the second concentric circle is the inlet for the mixed material of multi-component organic waste and water-coal slurry, and the outermost concentric circle is the epoxy inlet.

[0064] See also Figure 2 The present invention uses ICEM CFD software to mesh the gasification and melting furnace. Due to the symmetry of the gasification furnace itself, selecting a 1 / 4 model for modeling can reduce the number of mesh divisions and the calculation time. In order to ensure the quality of the mesh and the symmetry of the result, the present invention uses a hexahedral structure mesh. The meshing method steps are as follows: open the ICEM software to import the physical model, then create blocks, split blocks, and associate blocks according to the model, set mesh parameters and encrypt the mesh near the vertical direction of the nozzle, generate a mesh and check the mesh quality, and finally save the mesh.

[0065] See also Figure 3This is a vertical cross-section of the gasifier after meshing. The mesh is a hexahedral structured mesh, and the mesh is reasonably encrypted near the vertical area of ​​the nozzle.

[0066] See also Figure 4 Set up a flowchart for Fluent. Fluent is responsible for solving the model, and its specific steps are:

[0067] (1) Import the divided mesh file into Fluent software and check the mesh quality. Make sure the units of the mesh are consistent with those in the computational domain.

[0068] (2) Select the pressure-based steady-state solver, select the computational model and set the computational model parameters, including activating the realizable K-epsilon turbulence model, the P1 radiation model, the energy model, the discrete phase model, and the Finite-Rate / Eddy-Dissipation in the component transport model.

[0069] (3) Select the coal-hv-volatiles-air mixed material in the component transport model and add CH according to the actual situation of the factory. 2 Cl 2 , CO, H 2 , HCl and other materials and set the material properties.

[0070] (4) The combustion reaction is simplified to the combustion of the main average organic matter without halogen and the organic matter containing halogen. The specific chemical reaction formula is:

[0071] hv_vol+2O 2 =aCO+bH 2 +cCO 2 +dH 2 O

[0072] CH 2 Cl 2 +O 2 =CO 2 +2HCl

[0073] The values ​​of a, b, c, and d are used as the ratio coefficients of the synthesis gas, which are determined by the synthesis gas CO, H 2 , CO 2 , H 2 O ratio is calculated. Wherein X is selected from the halogens fluorine, chlorine, bromine and iodine, and is selected based on the halogen species contained in the multi-component organic waste measured in step 1. In this example, the multi-component organic waste mainly contains high chlorine elements, so X is selected as Cl.

[0074] (5) Set the discrete phase injection source type to surface. The pyrolysis component hv_vol is the assumed average combustion organic matter. The specific molecular weight of hv_vol can be obtained based on the actual synthesis gas ratio and the specified chemical reaction formula, and the molecular weight of hv_vol can be modified.

[0075] (6) The step of defining boundary conditions is to set the boundary conditions of the physical model in Fluent according to the gasifier slurry flow, gasifier pressure, gasifier oxygen flow, gasifier inlet temperature, gasifier outlet temperature, and furnace wall temperature collected in step 1, and perform boundary constraints on it.

[0076] (7) After the initialization is set, iterative calculation is performed to obtain the basic physical quantities in the high-temperature melting gasifier, including the distribution of hydrogen halide gas.

[0077] See also Figure 5 This is the velocity vector diagram of the vertical section of the gasifier. The highest speed in the figure is the oxygen flow rate of 50m / s at the nozzle, and the feed oxygen is pure oxygen. Due to the violent mixing reaction of the materials in the vertical section of the gasifier, the speed slows down and diverges as the reaction proceeds. At the outlet of the gasifier, the materials converge due to the narrowing of the outlet, and the velocity gradient increases again. The front half of the gasifier is in a jet-like shape, which proves that the material reacts violently in this area, which means that the material utilization rate is high in this process.

[0078] See also Figure 6 This is the temperature cloud map of the vertical section of the gasifier. The multi-component organic hazardous waste mixture will undergo evaporation, pyrolysis, combustion, gasification and other processes due to the high temperature environment when entering the gasifier. It can be seen from the temperature cloud map that the combustion in the gasifier is in the form of flame. The temperature in the range of 0.5m-2m below the nozzle is as high as 3500-3700℃. Violent and rapid combustion reactions occur in this range. After leaving this range, the temperature shows a gradient decrease. This is because the materials and oxygen in the violent reaction zone are consumed too quickly, resulting in a gradual decrease in the combustion reaction in other areas, which is more inclined to radiation heat transfer. The furnace wall temperature of 1400℃ is consistent with the actual furnace wall temperature range of 1300-1400℃ measured by the factory thermocouple, which illustrates the accuracy of the temperature field simulation.

[0079] See also Figure 7 This is the CO molar mass cloud diagram of the vertical section of the gasifier. It can be seen from the figure that the concentration of CO is extremely low near the nozzle, but as the material is ejected downward, the molar mass concentration of CO decreases in a flame-like step-by-step manner, and the center of the flame is the highest concentration point. This is because the speed is highest at the nozzle, and the material and oxygen are not mixed sufficiently near the nozzle, resulting in a slow reaction. As the combustion flame temperature increases, it means that the reaction is more intense. The CO molar mass cloud diagram can reflect the intensity of the reaction between the material and oxygen, which is in line with the law of the temperature cloud diagram.

[0080] See also Figure 8H is the vertical section of the gasifier 2 Molar mass cloud diagram, showing H 2 The molar mass cloud diagram is similar to the molar mass of CO. This is because the main combustion material is set to average combustion of organic matter during the simulation. This method avoids too many complex chemical reactions. While ensuring the simulation accuracy, the calculation is easier to converge. The products of a total chemical reaction formula have similar distribution patterns, but the molar masses of their products are different. In industry, the concentration of syngas at the outlet is mainly examined.

[0081] See also Fig. 9 This is a comparison chart of the simulated value and actual value of the synthesis gas at the gasifier outlet. The synthesis gas at the gasifier outlet is the most important indicator of the gasifier. There are facilities for real-time monitoring in the process. By comparing the molar fractions of the simulated value and actual value of the synthesis gas at the gasifier outlet, the accuracy of the simulation can be judged. It can be seen from the figure that the error between the simulated value and the actual value is between 1-2%, so the accuracy of the method of the present invention can be judged.

[0082] See also Fig.10 This is the molar mass cloud diagram of HCl in the vertical section of the gasifier. It can be seen from the figure that the HCl concentration gradient is flame-like. In this process, the proportion of organic chlorine is 5% of the material mass fraction. At this time, the simulation results show that the HCl gas concentration can reach a maximum of 0.45 mol / m near the nozzle of the gasifier. 3 This is because the content of organic chlorine in the simulation only accounts for 5% of the total reactants, so the organic chlorine will react first. The central flame area is mainly due to the average combustion of organic matter. The HCl concentration at the furnace wall is 0.27-0.32 mol / m 3 In order to ensure the long-term stable operation of the gasifier, this value provides a reference for the corrosion of refractory bricks in the furnace.

[0083] It can be seen from the above examples that the method of the present invention is highly accurate in the process of high-temperature gasification furnace for multi-component organic waste from the perspective of temperature cloud map and outlet synthesis gas. It mainly provides a numerical simulation of hydrogen halide gas in a high-temperature gasification furnace, and can also obtain the most important temperature cloud map and synthesis gas information in the gasifier.

[0084] The present invention selects appropriate process parameters and test parameters, simplifies the complex reactions in the gasification reaction process of multi-component organic waste, and simulates the generation of hydrogen halide in the multi-component organic waste gasifier by using a computer numerical simulation method. The simplified model reflects the main reaction process in the gasifier, and the error between the synthetic gas simulation value and the experimental value is 2%, which verifies the accuracy of the prediction method. The patent provides a prediction method for hydrogen halide in a high-temperature gasifier of multi-component organic waste. The prediction method is simple and efficient, and the calculation efficiency is high. The value of hydrogen halide distribution in the high-temperature gasifier of multi-component organic waste provided by the patent provides a numerical basis for the factory to prevent and control the corrosion of refractory bricks of the gasifier, which is beneficial to improve the service life of the gasifier and thus improve the economic benefits of the factory.

Claims

1. A method for predicting hydrogen halides in a high-temperature gasifier for multi-component organic waste, the characteristics of which include Follow these steps: Step 1, measuring and collecting data during the operation of an actual multi-component organic waste high-temperature gasification furnace, wherein the measured data include the halogen content in the multi-component organic waste and the proportion of synthesis gas at the outlet of the gasifier, and the collected data include the size of the gasifier, the size of the gasifier nozzle, the pressure in the gasifier, the slurry flow rate, the oxygen flow rate, and the furnace wall temperature; Step 2, using the gasifier size, nozzle size, furnace pressure, slurry flow rate, oxygen flow rate, and furnace wall temperature parameters collected in step 1 to establish a gasifier geometric model, divide the geometric model into structured grids, and determine the calculation area; Step 3, a hypothesis is proposed for the high-temperature melt gasifier, and the gasification reaction process of the multi-component organic waste is simplified into the reaction of the main average organic matter and the reaction of the halogen-containing organic matter; the molecular weight of the main average organic matter is inferred by using the synthesis gas ratio measured in step 1; Using the types of halogens in the multi-component organic waste determined in step 1, determine the type of halogen selected for simulation; Assumptions made for the gasifier include: 3.1) Only the combustion process of combustible components is considered in the gasifier, and the influence of ash is not considered; 3.2) The combustible components are simplified to the main average burning organic matter without halogen and the organic matter containing halogen; 3.3) The main average combustion organic matter without halogen is expressed as hv_vol; 3.4) Halogen-containing organic matter is simplified to CH2X2; where X is selected from the halogens fluorine, chlorine, bromine, and iodine, and the mass fraction of CH2X2 in the assumed combustible component is obtained by converting the mass fraction of halogens in the multi-component organic waste measured in step 1; 3.5) The initial velocity and flow rate of fuel and oxidant are constant; 3.6) The combustion gas products are simplified to synthesis gas and HX consisting of CO, CO2, H2, H2O; Step 4, import the model of step 2 into Fluent, select the turbulence model, radiation model, energy model, discrete phase model and component transport model in the calculation model and set the calculation model parameters, set the chemical reaction equation and the molecular weight of the main average organic matter and halogen-containing organic matter assumed in step 3, and set the boundary conditions and solver; the specific steps of step 4 are as follows: 4.1) Import the model in step 2 into Fluent; 4.2) Select the steady-state solver based on pressure basis, select the turbulence model, radiation model, energy model, discrete phase model and component transport model in the calculation model and set the calculation model parameters. The component transport model selects the Finite-Rate / Eddy-Dissipation model; 4.3) Select the coal-hv-volatiles-air mixed material in the component transport model and add CH2X2, CO, H2, HX materials according to the actual situation of the factory and set the material properties; 4.4) The combustion reaction is simplified to the combustion of the main average organic matter without halogen and the organic matter containing halogen. The specific chemical reaction formula is: hv_vol+2O2=αCO+bH2+cCO2+dH2O CH2X2+O8=CO8+2HX The values ​​of a, b, c, and d are calculated as the ratio coefficients of the synthesis gas from the ratios of CO, H2, CO2, and H2O in the synthesis gas determined in step 1; 4.5) Set the discrete phase injection source type to surface, the pyrolysis component is the assumed halogen-free main average combustion organic matter hv_vol, and modify the molecular weight of hv_vol; 4.6) Set the boundary conditions of the physical model in Fluent according to the gasifier slurry flow, gasifier pressure, gasifier oxygen flow, gasifier inlet temperature, gasifier outlet temperature, and furnace wall temperature collected in step 1; 4.7) After initialization, perform iterative calculation to obtain calculation result data; Step 5, post-processing the data obtained after the Fluent calculation is completed to obtain a distribution cloud map of hydrogen halide in the gasifier.

2. The method for predicting hydrogen halide in a high-temperature gasification furnace for multi-component organic waste according to claim 1, characterized in that In step 1, the halogen content in the multi-component organic waste includes the content of fluorine, chlorine, bromine and iodine; the halogen content needs to be sampled multiple times to obtain the average value, and the synthesis gas needs to correspond to the multi-component organic hazardous waste one by one, and multiple samples need to be sampled to obtain the average value.

3. The method for predicting hydrogen halide in a high-temperature gasification furnace for multi-component organic waste according to claim 1, characterized in that In step 2, the specific steps for establishing the geometric model of the gasifier are: according to the structure and size of the high-temperature melting gasifier, the geometric model of the high-temperature melting gasifier is established in combination with the nozzle structure and taking into account the actual production situation; since the high-temperature melting gasifier is a central axis symmetrical structure, the geometric model is simplified to 1 / 4 of the whole for subsequent meshing.

4. The method for predicting hydrogen halide in a high-temperature gasifier of multi-component organic waste according to claim 1, characterized in that In step 2, the geometric model is structured and the calculation area is determined. The specific steps are as follows: 2.1) Select the furnace area of ​​the built 1 / 4 gasifier geometric model as the calculation area; 2.2) Divide the computational domain into hexahedral structured grids to form an overall symmetrically distributed hexahedral structured grid, examine the grid quality and the number of grids, determine the number of grid nodes, and obtain a high-quality hexahedral structured grid; 2.3) Define the solution domain, name the boundary conditions of the gasifier surface, and save the file.

5. The method for predicting hydrogen halide in a high-temperature gasification furnace for multi-component organic waste according to claim 4, characterized in that In step 2.3, the interior of the gasifier, the nozzle inlet plane, and the gasifier outlet plane are defined as the solution domain; the naming of the boundary conditions of the gasifier surface is specifically: the nozzle inlet is named as the inlet, the gasifier outlet is named as the outlet, and the gasifier furnace wall is named as the wall.

6. The method for predicting hydrogen halide gas in a high-temperature gasifier for multi-component organic waste according to claim 1, characterized in that: The main average combustion organic matter hv_vol without halogen represents the mixed material. The specific molecular weight of hv_vol is obtained according to the actual synthesis gas ratio and the chemical reaction formula specified above and the molecular weight of hv_vol is modified in step 4.5).

7. The method for predicting hydrogen halide gas in a high-temperature gasifier for multi-component organic waste according to claim 1, characterized in that In step 4, the specific steps for setting boundary conditions for Fluent are: according to the gasifier slurry flow, gasifier pressure, gasifier oxygen flow, gasifier inlet temperature, gasifier outlet temperature, and furnace wall temperature collected in step 1, the boundary conditions of the physical model in Fluent are set to perform boundary constraints.

8. The method for predicting hydrogen halide gas in a high-temperature gasifier for multi-component organic waste according to claim 1, characterized in that In step 5, the post-processing method includes: outputting the Fluent simulation results as graphics or curves, and displaying the hydrogen halide gas fractionation, synthesis gas distribution and temperature distribution in the high-temperature melt gasifier through distribution cloud maps and data maps after post-processing.

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