A calculation and analysis method for dry desulfurization in pulverized coal furnaces

Abstract

A computational analysis method for in-furnace dry desulfurization in pulverized coal furnaces, involving pulverized coal boiler tail gas purification, is presented. 1) Model partitioning is established: Based on the geometric dimensions and computational accuracy of an industrial-grade pulverized coal furnace, the furnace is divided from bottom to top into n series reaction chambers. 2) Model feed parameters include coal quality analysis data, coal feed rate, air feed rate, desulfurizer composition and Ca / S ratio, desulfurizer-carrier gas ratio, and desulfurizer feed position. 3) A furnace combustion process model is established. This method combines an industrial-grade air-staged combustion pulverized coal furnace model with three sulfur conversion models based on sulfur release, calcium carbonate decomposition and sintering, and sulfur capture. Actual industrial operating parameters are used as model input parameters, and the established model is solved to determine the desulfurization efficiency of in-furnace dry desulfurization. This method can also be used to study the effects of calcium-based desulfurizer composition, Ca / S ratio, and furnace feed position on the desulfurization effect, providing a reference for the design of in-furnace desulfurization in air-staged combustion pulverized coal furnaces.

Description

Technical Field

[0001] The present invention relates to the field of tail gas purification of pulverized coal boilers, and in particular to a calculation and analysis method applicable to dry desulfurization in pulverized coal boilers, which obtains the influence of operating parameter changes on dry desulfurization of pulverized coal boilers by solving a mathematical model. Background Art

[0002] Sulfur dioxide is one of the main atmospheric pollutants. As national environmental protection standards increase, SO2 emissions in flue gases must be lowered. In-furnace dry desulfurization captures SO2 within the furnace. Compared to wet desulfurization, this eliminates the need for large equipment such as desulfurization towers and spray dryers, making it easier to apply to existing boilers.

[0003] In-furnace dry desulfurization, a calcium-based desulfurizer is injected into a specific area within the furnace. Rapid calcination generates CaO, which then reacts with SO₂ and O₂ to form CaSO₄. This reaction is a complex, high-temperature, rapid, heterogeneous reaction. The sulfation process is influenced by factors such as reaction temperature, SO₂ concentration, adsorbent composition, particle size, and the structure of the newly formed CaO. Desulfurizer sintering and calcium sulfate decomposition occur in high-temperature areas within the furnace, impacting overall desulfurization efficiency. Parameters such as desulfurizer composition, Ca / S ratio, and desulfurizer feed location require optimized design during dry desulfurization. Adjusting dry desulfurization parameters during industrial boiler operation can pose significant safety risks and economic pressures. Simulation offers an efficient and safe alternative. Suhas et al. (Suhas K. Mahuli et al. Combined calcination, sintering and sulfation model for CaCO3-SO2 reaction. AIChE J., 1999, 45(2): 367-382.) established a single-particle CaO reaction model based on the grain-subgrain concept, taking into account the accompanying calcination, sintering and sulfation reactions. Based on this, the present invention combines the flow and stress characteristics in a pulverized coal furnace to establish a mathematical model for the calcium-based desulfurization process in a pulverized coal furnace, realizing the calculation of desulfurization efficiency under different parameters such as desulfurizer composition, Ca / S ratio, and desulfurizer feed position. Summary of the Invention

[0004] The purpose of the present invention is to provide a calculation and analysis method suitable for dry desulfurization in a pulverized coal furnace, which obtains the influence of different components of desulfurizer, Ca / S ratio, feed position in the furnace, etc. on the desulfurization efficiency by solving a set of differential equations, thereby providing a reference for the design of dry desulfurization in a pulverized coal furnace.

[0005] The present invention comprises the following steps:

[0006] (1) Establish model partitions: Based on the geometric dimensions and calculation accuracy of the industrial-grade pulverized coal furnace, the pulverized coal furnace is divided from bottom to top into n series reaction chamber areas;

[0007] (2) Feed parameters in the model: coal quality analysis data, coal feed rate, air feed rate, desulfurizer composition and Ca / S ratio, desulfurizer carrier gas ratio, and desulfurizer feed position;

[0008] (3) Establishing the combustion process model in the furnace: The combustion in the furnace includes the carbon combustion model and the gas phase combustion;

[0009] Among them, the carbon combustion model adopts the shrinking core model, and the combustion rate is as follows:

[0010]

[0011] Where: R C,j,i represents the combustion rate of coke in the feed coal of the jth reaction chamber in the i-th reaction chamber, kg / s, R C,i represents the total coke combustion rate in the i-th reaction chamber, kg / s;

[0012] The combustion rate of gas phase combustion is as follows:

[0013] R g,i =n i ∑ r v g,r R r,i

[0014] R g,i represents the reaction rate of component g in the first reaction chamber, kmol / (m 3 ·s), where g includes 11 substances such as O2, N2, NH3, NO, CH4, C2H4, CO2, H2O, SO2, H2S, and COS, and n i Indicates the amount of substance in the flue gas in the i-th reaction chamber, kmol, v g,r Represents the stoichiometric coefficient of component g in chemical reaction r, R r,i represents the reaction rate of chemical reaction r in chamber i, 1 / (m 3 s);

[0015] (4) Establishing a sulfur conversion model: The dry desulfurization reaction in the furnace includes the decomposition and sintering reaction of calcium carbonate, the sulfation reaction of calcium oxide, and the decomposition and reduction reaction of calcium sulfate;

[0016] The rate at which calcium carbonate decomposes is as follows:

[0017]

[0018] Where R Ca,i represents the decomposition rate of calcium carbonate in the reaction chamber of layer i, kg / (m 3 ·s), k Ca,i represents the rate constant of calcium carbonate calcination in the i-th layer reaction chamber, m / s, ρCa Represents the density of calcium carbonate, kg / m 3 , represents the mass concentration of calcium carbonate in the reaction chamber of layer i, kg / m 3 , Represents the specific surface area of ​​calcium carbonate, m 2 / kg, P e represents the equilibrium decomposition pressure of calcium carbonate, kPa, represents the partial pressure of carbon dioxide in the reaction chamber of layer i, kPa;

[0019] The rate of the calcium oxide sulfation reaction is as follows:

[0020]

[0021]

[0022] logr G0,j =-23.33+nlogT g,i

[0023] Where R S1,j,i represents the reaction rate of calcium oxide entering or generated in the j-layer reaction chamber in the i-layer reaction chamber, kmol / (m 3 ·s), k s represents the calcium oxide sulfation reaction rate constant, m 4 / (kmol·s), r G,j,i represents the radius of the calcium oxide particles entering or generated in the j-th layer reaction chamber in the i-th layer reaction chamber after partial sulfation, m, r G0,j represents the initial radius of the calcium oxide particles entering or generated in the j-th layer reaction chamber, m, c CaO,i represents the molar concentration of calcium oxide in the reaction chamber of layer i, kmol / m 3 , represents the concentration of sulfur dioxide in the reaction chamber of layer i, kmol / m 3 , z represents the molar volume ratio of calcium sulfate to calcium oxide, which is 3.09, r c,j,i represents the radius of the calcium oxide that enters or is generated in the jth layer reaction chamber and remains unreacted in the ith layer. m and n represent the effects of high-temperature sintering, and their values ​​are affected by the type of calcium carbonate.

[0024] The decomposition and reduction reaction rates of calcium sulfate are as follows:

[0025]

[0026]

[0027] Where R S2,j,irepresents the decomposition rate of calcium sulfate generated in the j-layer reaction chamber in the i-layer, kmol / (m 3 ·s), R S3,j,i represents the reduction rate of calcium sulfate generated in the j-layer reaction chamber in the i-layer, kmol / (m 3 s), represents the molar concentration of calcium sulfate in the reaction chamber of layer i, kmol / m 3 , k d represents the calcium sulfate decomposition reaction rate constant, m / s, k r represents the calcium sulfate reduction reaction rate constant, m 4 / (kmol·s);

[0028] The SO2 reaction rate in the reaction chamber of layer i is as follows:

[0029]

[0030] Where, represents the reaction rate of sulfur dioxide in the i-th layer reaction chamber, kmol / (m 3 ·s), R S,i represents the sulfur dioxide generation rate of the gas phase homogeneous reaction in layer i, kmol / (m 3 s);

[0031] (5) Basic conservation equations: Based on the full mixed flow model, the mass conservation and energy conservation differential equations of each component in each reaction chamber are established;

[0032] The solid phase mass conservation equation is:

[0033]

[0034] Where V i Represents the volume of the reaction chamber at layer i, m 3 , c s,j,i Represents the mass concentration of solid s entering layer j in layer i, kg / m 3 , where solid s represents coke, ash, calcium oxide, calcium sulfate and calcium carbonate, F s,i Represents the mass of solid s entering the i-th layer, kg / s, Q i Represents the volume flow rate at the outlet of layer i, m 3 / s;R s,i Represents the reaction rate of the solid s in layer i, kg / (m 3 s);

[0035] The gas phase mass conservation equation is:

[0036]

[0037] Where xg,i represents the volume fraction of the gas g in the i-th layer, F g,i represents the molar amount of the feed gas component g in the i-th layer, kmol / s, N i represents the molar flow rate of the gas at the outlet of layer i, kmol / s, R g,i represents the reaction rate of the gas component g in layer i, kmol / (m 3 s);

[0038] The energy conservation equation is:

[0039]

[0040] Where c n,i represents the concentration of component n in layer i, kmol / m 3 , n includes gas components and solid components, C pn ,i represents the specific heat capacity of component n in layer i, kJ / (kmol·K), Q h,in,i Represents the energy of the feed in layer i, kJ / s, Q h,i Represents the energy flowing from layer i to layer i+1, kJ / s, Q R,i Represents the energy released by the chemical reaction at layer i, kJ / s, Q ra,i Represents the energy of radiation heat transfer from layer i to adjacent reactors and water-cooled walls, kJ / s, Q w,i represents the heat loss energy of the i-th layer, kJ / s;

[0041] (6) Model solution: The differential equations can be solved by programming or using Matlab to output the dry desulfurization efficiency in the furnace;

[0042] The calculation equation for desulfurization efficiency is:

[0043]

[0044] Where η S Represents the desulfurization efficiency, Represents the concentration of SO2 at the outlet of the model without adding desulfurizer when the reference oxygen content is 6%, mg / Nm 3 , Represents the concentration of SO2 at the outlet of the model after adding desulfurizer when the reference oxygen content is 6%, mg / Nm 3 .

[0045] In step (1), the reaction chamber is assumed to be a fully mixed flow reactor, and based on the reaction rate of each component in each reaction chamber, the mass conservation and energy conservation equations of each reaction chamber are established.

[0046] In step (2), the desulfurizer components are mainly CaCO3 and CaO, and the carrier gas ratio is 0.3 to 5; the parameters such as the desulfurizer components, Ca / S ratio, and the desulfurizer feed position can be adjusted. After adjustment, it is only necessary to repeat steps (2) to (6) to obtain the desulfurization efficiency under different parameters.

[0047] The beneficial effects of the present invention are as follows: the present invention establishes a calculation model for dry desulfurization in a pulverized coal furnace, uses actual industrial operating parameters as model input parameters, and solves the established model to calculate the desulfurization efficiency of the dry desulfurization in the furnace. This method can also be used to study the influence of calcium-based desulfurizer components, Ca / S ratio, furnace feed position, etc. on the desulfurization effect. The provided method can provide a reference basis for the design of desulfurization in an air-staged combustion pulverized coal furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of the partitioning of an air-staged combustion pulverized coal furnace.

[0049] Figure 2 It is a schematic flow diagram of the present invention.

[0050] Figure 3 The present invention calculates the effects of different Ca / S ratios and feed positions on the desulfurization efficiency in the furnace. DETAILED DESCRIPTION

[0051] The present invention will be further described with reference to the following embodiments and accompanying drawings.

[0052] The present invention provides a calculation method for dry desulfurization in a pulverized coal furnace, which can predict the desulfurization efficiency of a calcium-based desulfurizer in the furnace and provide a reference for the design of dry desulfurization in the furnace.

[0053] Pulverized coal furnace Figure 1 The furnace is divided into n reaction chambers from bottom to top, as shown. Each reaction chamber is considered a fully mixed-flow reactor, with the value of n determined by the furnace structure and calculation accuracy. The air-staged combustion system uses multi-stage feeding. After the pulverized coal and desulfurizer are introduced into the furnace, they are transported upward with the flue gas from bottom to top.

[0054] The process of the present invention is as follows Figure 2 As shown, the present invention is introduced below with reference to an example of an industrial-grade four-corner circular cut air-staged combustion pulverized coal furnace.

[0055] A pulverized coal-fired boiler, manufactured by Shanghai Boiler Plant, features ultra-high pressure, high temperature, four-corner tangential firing, natural circulation, a single furnace, no reheat, balanced ventilation, solid slag removal, and a "П"-type drum layout. Its main steam flow rate at rated load is 670 t / h. The raw coal is ground and dried in five medium-speed pulverizers and then fed by primary air to 20 direct current burners distributed throughout the furnace. The boiler utilizes balanced ventilation and a two-stage sectional air system, with 56 burners arranged on 14 levels.

[0056] Step 1: In this embodiment, the model is divided into 19 reaction chambers connected in series according to the furnace structure and calculation accuracy.

[0057] Step 2: Input feed parameters. Coal quality analysis data, coal feed rates for each reaction chamber, and air feed rates are shown in Tables 1 and 2, respectively. The desulfurizer is composed of 90% CaCO₃ and 10% CaO by mass, with an average particle size of 50 μm. The desulfurizer-carrier gas ratio is 0.5, and the Ca / S ratio is 0.5. The desulfurizer is introduced into the 16th reaction chamber.

[0058] Table 1 Coal quality analysis data

[0059]

[0060] Table 2 Coal and air inlet to the reaction chamber

[0061]

[0062] Step 3: Combustion in the furnace includes the carbon combustion model and gas phase combustion. The carbon combustion adopts the shrinking core model, and the combustion rate is shown in the following equation:

[0063]

[0064] Where: R C,j,i represents the combustion rate of coke in the coal entering the jth reaction chamber in the i-th reaction chamber, kg / s, R C,i Represents the total coke combustion rate in the i-th reaction chamber, kg / s.

[0065] The gas phase combustion rate is calculated according to the following equation:

[0066] R g,i =n i ∑ r v g,r R r,i

[0067] R g,i represents the reaction rate of component g in the first reaction chamber, kmol / (m 3 ·s), where g includes 11 substances such as O2, N2, NH3, NO, CH4, C2H4, CO2, H2O, SO2, H2S, and COS, and n i Indicates the amount of substance in the flue gas in the i-th reaction chamber, kmol, v g,r Represents the stoichiometric coefficient of component g in chemical reaction r, R r,i represents the reaction rate of chemical reaction r in chamber i, 1 / (m 3 ·s).

[0068] Step 4: The dry desulfurization reaction in the furnace includes the decomposition and sintering reaction of calcium carbonate, the sulfation reaction of calcium oxide, and the decomposition and reduction reaction of calcium sulfate. Its model is described according to the reaction kinetic model.

[0069] The decomposition rate of calcium carbonate is calculated according to the following equation:

[0070]

[0071] Where R Ca,i represents the decomposition rate of calcium carbonate in the reaction chamber of layer i, kg / (m 3 ·s), k Ca,i represents the rate constant of calcium carbonate calcination in the i-th layer reaction chamber, m / s, ρ Ca Represents the density of calcium carbonate, kg / m 3 , represents the mass concentration of calcium carbonate in the reaction chamber of layer i, kg / m 3 , Represents the specific surface area of ​​calcium carbonate, m 2 / kg, P e represents the equilibrium decomposition pressure of calcium carbonate, kPa, Represents the partial pressure of carbon dioxide in the i-th layer reaction chamber, kPa.

[0072] The calcium oxide sulfation rate is calculated according to the following equation:

[0073]

[0074]

[0075] logr G0,j =-23.33+nlogT g,i

[0076] Where R S1,j,i represents the reaction rate of calcium oxide entering or generated in the j-layer reaction chamber in the i-layer reaction chamber, kmol / (m 3 ·s), k s represents the calcium oxide sulfation reaction rate constant, m 4 / (kmol·s), r G,j,i represents the radius of the calcium oxide particles entering or generated in the j-th layer reaction chamber in the i-th layer reaction chamber after partial sulfation, m, r G0,j represents the initial radius of the calcium oxide particles entering or generated in the j-th layer reaction chamber, m, c CaO,i represents the molar concentration of calcium oxide in the reaction chamber of layer i, kmol / m 3 , represents the concentration of sulfur dioxide in the reaction chamber of layer i, kmol / m 3, z represents the molar volume ratio of calcium sulfate to calcium oxide, which is 3.09, r c,j,i It represents the radius of the unreacted calcium oxide that enters or is generated in the j-th layer reaction chamber in the i-th layer, m, and n represent the influence of high-temperature sintering and are taken as 5.87.

[0077] The decomposition and reduction reaction rates of calcium sulfate are calculated according to the following equation:

[0078]

[0079]

[0080] Where R S2,j,i represents the decomposition rate of calcium sulfate generated in the j-layer reaction chamber in the i-layer, kmol / (m 3 ·s), R S3,j,i represents the reduction rate of calcium sulfate generated in the j-layer reaction chamber in the i-layer, kmol / (m 3 s), represents the molar concentration of calcium sulfate in the reaction chamber of layer i, kmol / m 3 , k d represents the calcium sulfate decomposition reaction rate constant, m / s, k r represents the calcium sulfate reduction reaction rate constant, m 4 / (kmol·s).

[0081] The SO2 reaction rate in the reaction chamber of layer i is calculated according to the following equation:

[0082]

[0083] Where, represents the reaction rate of sulfur dioxide in the i-th layer reaction chamber, kmol / (m 3 ·s), R S,i represents the sulfur dioxide generation rate of the gas phase homogeneous reaction in layer i, kmol / (m 3 ·s).

[0084] Step 5: Based on the full mixed flow model, establish a set of differential equations for mass conservation and energy conservation for each component in each reaction chamber.

[0085] The solid phase mass conservation equation is:

[0086]

[0087] Where V i Represents the volume of the reaction chamber at layer i, m 3 , c s,j,i Represents the mass concentration of solid s entering layer j in layer i, kg / m 3, where solid s represents coke, ash, calcium oxide, calcium sulfate and calcium carbonate, F s,i Represents the mass of solid s entering the i-th layer, kg / s, Q i Represents the volume flow rate at the outlet of layer i, m 3 / s. R s,i Represents the reaction rate of the solid s in layer i, kg / (m 3 ·s).

[0088] The gas phase mass conservation equation is:

[0089]

[0090] Where x g,i represents the volume fraction of the gas g in the i-th layer, F g,i represents the molar amount of the feed gas component g in the i-th layer, kmol / s, N i represents the molar flow rate of the gas at the outlet of layer i, kmol / s, R g,i represents the reaction rate of the gas component g in layer i, kmol / (m 3 ·s).

[0091] The energy conservation equation is:

[0092]

[0093] Where c n,i represents the concentration of component n in layer i, kmol / m 3 , n includes gas components and solid components, C pn,i represents the specific heat capacity of component n in layer i, kJ / (kmol·K), Q h,in,i Represents the energy of the feed in layer i, kJ / s, Q h,i Represents the energy flowing from layer i to layer i+1, kJ / s, Q R,i Represents the energy released by the chemical reaction at layer i, kJ / s, Q ra,i Represents the energy of radiation heat transfer from layer i to adjacent reactors and water-cooled walls, kJ / s, Q w,i Represents the heat loss energy of the i-th layer, kJ / s.

[0094] Step 6: Model solution. In this embodiment, Matlab is used to solve the differential equations and output the dry desulfurization efficiency in the furnace.

[0095] The calculation equation for desulfurization efficiency is:

[0096]

[0097] Where η S Represents the desulfurization efficiency, Represents the concentration of SO2 at the outlet of the model without adding desulfurizer when the reference oxygen content is 6%, mg / Nm 3 , Represents the concentration of SO2 at the outlet of the model after adding desulfurizer when the reference oxygen content is 6%, mg / Nm 3 .

[0098] Change the Ca / S ratio and the desulfurizer feed position in step 2, repeat steps 2 to 6, and obtain the desulfurization efficiency of the boiler with different Ca / S ratios and different desulfurizer feed positions. Figure 3 shown.

[0099] The present invention combines an industrial-grade air-staged combustion pulverized coal furnace model with three sulfur conversion models based on sulfur release, calcium carbonate decomposition and sintering, and sulfur capture. The desulfurization efficiency of in-furnace dry desulfurization can be calculated by using actual industrial operating parameters as model input parameters and solving the established model. The present invention can also be used to study the effects of calcium-based desulfurizer components, Ca / S ratio, in-furnace feed position, etc. on the desulfurization effect. The provided method can provide a reference basis for the in-furnace desulfurization design of air-staged combustion pulverized coal furnaces.

Claims

1. A calculation and analysis method for dry desulfurization in a pulverized coal furnace, characterized in that The following steps are involved: (1) Establishing model partitions: Based on the geometric dimensions and calculation accuracy of the industrial-grade pulverized coal furnace, the pulverized coal furnace is divided into n series reaction chambers from bottom to top; the reaction chambers are assumed to be fully mixed-flow reactors, and based on the reaction rates of the components in each reaction chamber, the mass conservation and energy conservation equations for each reaction chamber are established; (2) Feed parameters in the model: coal quality analysis data, coal feed rate, air feed rate, desulfurizer composition and Ca / S ratio, desulfurizer carrier gas ratio, and desulfurizer feed position; The desulfurizer components are CaCO3 and CaO, and the carrier gas ratio is 0.3-5; the desulfurizer components, Ca / S ratio, and desulfurizer feed position parameters can be adjusted, and after adjustment, steps (2) to (6) are repeated to obtain the desulfurization efficiency under different parameters; (3) Establishing the combustion process model in the furnace: The combustion in the furnace includes the carbon combustion model and the gas phase combustion; Among them, the carbon combustion model adopts the shrinking core model, and the combustion rate is as follows: Where: R C,j,i represents the combustion rate of coke in the feed coal of the jth reaction chamber in the i-th reaction chamber, kg / s, R C,i represents the total coke combustion rate in the i-th reaction chamber, kg / s; The combustion rate of gas phase combustion is as follows: R g,i =n i Σ r v g,r R r,i R g,i represents the reaction rate of component g in the i-th reaction chamber, kmol / (m 3 ·s), where g includes O2, N2, NH3, NO, CH4, C2H4, CO2, H2O, SO2, H2S, COS, and n i Indicates the amount of substance in the flue gas in the i-th reaction chamber, kmol, v g,r Represents the stoichiometric coefficient of component g in chemical reaction r, R r,i represents the reaction rate of chemical reaction r in chamber i, 1 / (m 3 s); (4) Establishing a sulfur conversion model: The dry desulfurization reaction in the furnace includes the decomposition and sintering reaction of calcium carbonate, the sulfation reaction of calcium oxide, and the decomposition and reduction reaction of calcium sulfate; The rate at which calcium carbonate decomposes is as follows: Where R Ca,i represents the decomposition rate of calcium carbonate in the reaction chamber of layer i, kg / (m 3 ·s), k Ca,i represents the rate constant of calcium carbonate calcination in the i-th layer reaction chamber, m / s, ρ Ca Represents the density of calcium carbonate, kg / m 3 , represents the mass concentration of calcium carbonate in the reaction chamber of layer i, kg / m 3 , Represents the specific surface area of ​​calcium carbonate, m 2 / kg, P e represents the equilibrium decomposition pressure of calcium carbonate, kPa, represents the partial pressure of carbon dioxide in the reaction chamber of layer i, kPa; The rate of the calcium oxide sulfation reaction is as follows: logr G0,j =-23.33+nlogT g,i Where R S1,j,i represents the reaction rate of calcium oxide entering or generated in the j-layer reaction chamber in the i-layer reaction chamber, kmol / (m 3 ·s), k s represents the calcium oxide sulfation reaction rate constant, m 4 / (kmol·s), r G,j,i represents the radius of the calcium oxide particles entering or generated in the j-th layer reaction chamber in the i-th layer reaction chamber after partial sulfation, m, r G0,j represents the initial radius of the calcium oxide particles entering or generated in the j-th layer reaction chamber, m, c CaO,i represents the molar concentration of calcium oxide in the reaction chamber of layer i, kmol / m 3 , represents the concentration of sulfur dioxide in the reaction chamber of layer i, kmol / m 3 , z represents the molar volume ratio of calcium sulfate to calcium oxide, which is 3.09, r c,j,i represents the radius of the calcium oxide that enters or is generated in the j-th layer reaction chamber and remains unreacted in the i-th layer. m and n represent the effects of high-temperature sintering, and their values ​​are affected by the type of calcium carbonate. The decomposition and reduction reaction rates of calcium sulfate are as follows: Where R S2,j,i represents the decomposition rate of calcium sulfate generated in the j-layer reaction chamber in the i-layer, kmol / (m 3 ·s), R S3,j,i represents the reduction rate of calcium sulfate generated in the j-layer reaction chamber in the i-layer, kmol / (m 3 s), represents the molar concentration of calcium sulfate in the reaction chamber of layer i, kmol / m 3 , k d represents the calcium sulfate decomposition reaction rate constant, m / s, k r represents the calcium sulfate reduction reaction rate constant, m 4 / (kmol·s); The SO2 reaction rate in the reaction chamber of layer i is as follows: Where, represents the reaction rate of sulfur dioxide in the i-th layer reaction chamber, kmol / (m 3 ·s), R S,i represents the sulfur dioxide generation rate of the gas phase homogeneous reaction in layer i, kmol / (m 3 s); (5) Basic conservation equations: Based on the full mixed flow model, the mass conservation and energy conservation differential equations of each component in each reaction chamber are established; The solid phase mass conservation equation is: Where V i Represents the volume of the reaction chamber at layer i, m 3 , c s,j,i Represents the mass concentration of solid s entering layer j in layer i, kg / m 3 , where solid s represents coke, ash, calcium oxide, calcium sulfate and calcium carbonate, F s,i Represents the mass of solid s entering the i-th layer, kg / s, Q i Represents the volume flow rate at the outlet of layer i, m 3 / s;R s,i Represents the reaction rate of the solid s in layer i, kg / (m 3 s); The gas phase mass conservation equation is: Where x g,i represents the volume fraction of the gas g in the i-th layer, F g,i represents the molar amount of the feed gas component g in the i-th layer, kmol / s, N i represents the molar flow rate of the gas at the outlet of layer i, kmol / s, R g,i represents the reaction rate of the gas component g in layer i, kmol / (m 3 s); The energy conservation equation is: Where c n,i represents the concentration of component n in layer i, kmol / m 3 , n includes gas components and solid components, C pn,i represents the specific heat capacity of component n in layer i, kJ / (kmol·K), Q h,in,i Represents the energy of the feed in layer i, kJ / s, Q h,i Represents the energy flowing from layer i to layer i+1, kJ / s, Q R,i Represents the energy released by the chemical reaction at layer i, kJ / s, Q ra,i Represents the energy of radiation heat transfer from layer i to adjacent reactors and water-cooled walls, kJ / s, Q w,i represents the heat loss energy of the i-th layer, kJ / s; (6) Model solution: Use programming or Matlab to solve the differential equations and output the dry desulfurization efficiency in the furnace; The desulfurization efficiency is as follows: Where η S Represents the desulfurization efficiency, Represents the concentration of SO2 at the outlet of the model without adding desulfurizer when the reference oxygen content is 6%, mg / Nm 3 , Represents the concentration of SO2 at the outlet of the model after adding desulfurizer when the reference oxygen content is 6%, mg / Nm 3 .

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