Method for simplifying combustion mechanism of sludge pyrolysis gas and gas turbine system for verifying method

Abstract

The invention relates to a combustion mechanism simplification method of sludge pyrolysis gas and a gas turbine system for verifying the method, and provides a mechanism simplification method suitable for combustion, which combines a DRGEP method and a DRGPFA method, improves the numerical calculation precision in the combustion process of a gas turbine, and improves the combustion efficiency of the gas turbine. On the basis of ensuring the calculation precision, the component and element reaction number is reduced, the numerical calculation precision in the process of simulating the combustion of the sludge pyrolysis gas of the gas turbine and the numerical calculation efficiency in the working process are improved, the numerical simulation requirement can be ensured, and application can be conveniently carried out; meanwhile, the sludge pyrolysis gas is sprayed into the gas turbine to be combusted, the wet sludge is dried through high-temperature flue gas exhausted by the gas turbine, the energy utilization efficiency is effectively improved through high availability and reliability of combustion of the sludge pyrolysis gas serving as fuel, and the municipal sludge is effectively and harmlessly treated.

Description

Technical Field

[0001] The invention belongs to the technical field of simulation of sludge combustion, and in particular relates to a method for simplifying the combustion mechanism of sludge pyrolysis gas and a gas turbine system for verifying the method. Background Art

[0002] A gas turbine is an efficient and clean rotary power output device that converts the chemical energy of fuel into mechanical energy through combustion. In the combustion chamber of a gas turbine, the mixing, ignition and combustion process of the fuel is a very complex collision and compound process. The choice of fuel is crucial to the stability and efficiency of combustion in the gas turbine. At present, the field of gas turbine technology is focusing on the combustion system of gas turbines, carrying out research on flexible fuel low-pollution combustion technology, and solving a series of scientific problems related to combustion, including the selection of flexible fuels, the principle of flexible fuel flame stabilization and combustion oscillation control technology, the mechanism and control technology of flexible fuel NOx generation, and digital hydrogen fuel combustion chamber modeling and simulation; as well as mastering new combustion technologies and methods, to provide theoretical support for the realization of flexible fuel low-pollution combustion of advanced gas turbines. As a kind of biomass energy, the annual output of sewage sludge in countries around the world is increasing, so innovative and sustainable waste management solutions are needed. How to effectively and harmlessly treat urban sludge is a matter of great concern to domestic and foreign experts. The disposal of urban sludge mainly adopts landfill, composting, incineration, anaerobic digestion and other methods, but they all have certain limitations.

[0003] In order to improve the numerical calculation accuracy of the gas turbine combustion process, it is necessary to use the combustion reaction kinetic model of the fuel when numerically calculating the combustion process of the fuel in the gas turbine combustion chamber. In the exploration of the fuel combustion mechanism, multiple components and a large number of elementary reactions are involved, and there is a problem of low calculation efficiency. The extremely simplified one-step or two-step empirical combustion model cannot guarantee the accuracy of the calculation due to insufficient description of the combustion process. Therefore, the simplification of the combustion mechanism has become an important research direction in the field of combustion. At present, there are many ways to simplify complex reaction mechanisms. In addition, in complex kinetic models, the relative importance of each species is difficult to determine, and sensitivity analysis is required. Sensitivity analysis can effectively improve our understanding of the importance of chemical reaction processes in combustion models, and help determine the critical paths of the reaction processes in combustion models and the sensitivity of each reactant. At present, many studies have accurately predicted and analyzed the combustion behavior of fuels from a macroscopic perspective.

[0004] There are many methods to simplify the mechanism, but the simplified mechanism is single, and the simplified chemical reaction mechanism cannot meet the needs of numerical simulation. In addition, the combustion kinetics reaction of the gas turbine is incomplete during the simulation process. Therefore, it is necessary to propose a simplified mechanism method for fuel combustion in the gas turbine to analyze the fuel combustion mechanism. And the selection of fuel in the gas turbine needs to be further explored to meet the needs of carbon emissions. Summary of the invention

[0005] The purpose of the present invention is to solve at least one of the above-mentioned problems and to provide a method for simplifying the combustion mechanism of sludge pyrolysis gas and a gas turbine system for verifying the method, so as to solve the problem that the exhaust gas emitted by fuel combustion in the gas turbine in the prior art cannot meet the carbon emission requirements, and the problem that the gas turbine combustion kinetics reaction is incomplete in the process of simulating sludge pyrolysis gas combustion. By proposing a simplified mechanism method suitable for combustion, the numerical calculation accuracy and the numerical calculation efficiency of the working process in the process of simulating gas turbine combustion sludge pyrolysis gas are improved, which can not only meet the numerical simulation requirements but also be convenient for application. At the same time, sludge pyrolysis gas is used as gas turbine fuel, which realizes effective and harmless treatment of urban sludge and improves energy utilization efficiency.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a method for simplifying the fuel combustion mechanism applicable to a gas turbine, combining the DRGEP method with the DRGPFA method, comprising the following steps:

[0008] S1: Select the combustion model and its detailed reaction mechanism according to the fuel characteristics;

[0009] S2: The reaction mechanism was simplified using the DRGEP method to obtain simplified mechanism A;

[0010] S3: simplifying the simplified mechanism A using the DRGPFA method to obtain a simplified mechanism B;

[0011] S4: Perform sensitivity analysis on the simplified mechanism B;

[0012] S5: Verify the effectiveness of the simplified mechanism B. If it meets the requirements, output the simplified mechanism B. If it does not meet the requirements, optimize the detailed reaction mechanism and the simplified parameters of the DRGEP method and then re-execute step S2.

[0013] Furthermore, in step S1, the detailed reaction mechanism is a mechanism that is widely used and verified by a large number of experiments, or a chemical reaction mechanism that has been verified by experiments and is constructed in order to simulate and analyze the chemical composition in the actual fuel combustion process.

[0014] Furthermore, in step S1, the combustion model is selected from the PSR model in Chemkin.

[0015] Furthermore, in step S1, the detailed reaction mechanism is selected from the GRI-Mech3.0 mechanism for simulating methane combustion and the combustion mechanism for exploring the components in pyrolysis oil and pyrolysis gas.

[0016] In a specific embodiment, the combustion mechanism used to explore the components in pyrolysis oil and pyrolysis gas is selected from the pyrolysis oil and gas combustion elementary reaction mechanism in Appendix B2 of the paper [Sun Yunan. Research on the migration characteristics of mercury in the process of co-pyrolysis / incineration of sludge and garbage and product utilization [D]. Tianjin University, 2020. DOI: 10.27356 / d.cnki.gtjdu.2020.000433.].

[0017] Furthermore, in step S2, the DRGEP method is used to identify unimportant components and reactions in the detailed reaction mechanism of the fuel, and ultimately the elementary reactions that have a certain influence on the characteristic quantity of fuel combustion are obtained, thereby forming a simplified mechanism A of the gas turbine fuel.

[0018] In a specific embodiment, in step S2, CO, NO, N2O and HCl are set as key components, and the DRGEP method is used to identify unimportant components and reactions in the detailed reaction mechanism of the fuel. The error threshold of the simplification process is 20%, and finally the elementary reactions that have a certain influence on the fuel combustion characteristic quantity are obtained, thereby forming a simplified mechanism A of the gas turbine fuel.

[0019] Furthermore, in step S2, the DRGEP method is further improved based on the simplification principle of the direct relationship graph method (DRG), and simplifies according to the overall impact of all components on each reaction path, starting from the target component, searching to find the most important reaction path of each component, specifically:

[0020] The normalized contribution r of component A to the generation rate of component B is used AB To study the coupling relationship between component A and component B, the “R” value is used to determine the components stored in the mechanism. The “R” value also takes into account other components that can be obtained from these components through direct or indirect coupling, where r AB The formula with the "R" value is:

[0021]

[0022] In formula (1), P A and C A are the generation rate and consumption rate of component A, ν A,i is the stoichiometric coefficient of A, ω i is the production rate, δi B The value of is 1 (the ith elementary reaction contains B) or 0. By presetting a series of important components and threshold ε, ε is compared with r AB The size of r AB When ε < ε, it means that the effect of component B on A can be ignored. Removing B from the mechanism will not cause a large error in A, and the corresponding components and reactions can be removed. AB When ≥ε, it means that the contribution of B to A is large enough, and removing B from the mechanism will cause a large error in the prediction of A, and the path relationship will be retained; in formula (2), S is the set of all possible paths from component A to B, r ij is the product of the weight chains along A under a given reaction path.

[0023] Furthermore, in step S3, the DRGPFA method is used to select important reaction paths using the production flux and consumption flux between reactions, so that the mechanism of the fuel in the model is simplified to the greatest extent, and a simplified mechanism B of the gas turbine fuel is obtained.

[0024] Further, in step S3, the DRGPFA method is a new simplified method that combines the formation of DRG and the path flux method (PFA). The basic principle of this method is to replace the absolute reaction rate with the production flux and the consumption flux to identify the important reaction pathways, wherein the production flux P A With consumption flux C A The formula is (A represents substance A):

[0025]

[0026] In formula (3) and formula (4), ν A,i is the stoichiometric coefficient of A, ω i is the production rate.

[0027] In a specific embodiment, in step S3, CO, NO, N2O and HCl are set as key components, and the DRGPFA method is used to select important reaction paths using the production flux and consumption flux between reactions, so that the mechanism in the fuel in the model is simplified to the greatest extent, and the error threshold of the simplification process is 20%, thereby obtaining a simplified mechanism B of the gas turbine fuel.

[0028] Furthermore, in step S3, the components in the fuel are identified, screened, and eliminated by the DRGEP+DRGPFA simplification method to simplify the model to the greatest extent and obtain a simplified mechanism B of the gas turbine fuel.

[0029] Furthermore, in step S4, the simplified mechanism B is analyzed by a sensitivity analysis method to obtain elementary reactions that have a certain influence on the combustion characteristic quantity.

[0030] Furthermore, in step S4, the sensitivity analysis method can deeply analyze the specific reactions that occur during the combustion of the gas turbine fuel and the reactions that have a greater impact on the combustion process. The larger the value of the sensitivity coefficient, the greater the impact on the combustion process.

[0031] In a specific embodiment, by screening reactions whose absolute values ​​of sensitivity coefficients are within the sensitivity coefficient range, the specific reactions occurring during the combustion process and the reactions that have a greater impact on the combustion process are obtained. The sensitivity coefficient range is specifically: CO>0.015, NO>0.2, N2O>0.25, HCl>0.01.

[0032] Furthermore, in step S5, the validity verification is specifically as follows: comparative analysis is performed between the calculation results of the mechanism before simplification and the numerical calculation results of the simplified mechanism B. If the error is within 15%, it meets the requirements; if the error exceeds the set range (15%), it does not meet the requirements.

[0033] Furthermore, in step S5, the detailed mechanism is a combustion mechanism selected from the reaction mechanisms of existing specific experiments, and this simplified mechanism has been verified in experiments.

[0034] Further, in step S5, the method for optimizing the detailed reaction mechanism includes: adjusting the pre-exponential factor of the elementary reaction based on the sensitivity coefficients of different reactions obtained by sensitivity analysis;

[0035] The method for adjusting the simplified parameters of the DRGEP method includes: adjusting the error threshold of the simplification process.

[0036] The second technical solution of the present invention is to provide a gas turbine system for burning sludge pyrolysis gas, including a sludge drying subsystem, a pyrolysis gasification furnace, a gas turbine, and a generator;

[0037] The sludge drying subsystem performs graded drying treatment on the sludge. The dried sludge is transported to a pyrolysis gasification furnace for pyrolysis. The generated sludge pyrolysis gas is transported to a gas turbine for combustion. The heat energy is converted into electrical energy in a generator. The high-temperature flue gas emitted by the gas turbine provides a heat source for the sludge drying subsystem to dry the sludge.

[0038] Furthermore, the furnace temperature in the pyrolysis gasification furnace is 250°C-650°C, preferably 600°C, and the excess air coefficient is 0.2-0.6, preferably 0.2. Controlling the furnace temperature and oxygen intake can fully pyrolyze the organic components in the sludge.

[0039] Furthermore, natural gas and air are introduced into the gas turbine to burn together with the sludge pyrolysis gas. The sludge pyrolysis gasification can effectively destroy and kill pathogens, and the organic components in the sludge are converted into combustible gas, high calorific value fuel oil and part of the fixed carbon, and the remaining part is converted into residue, with obvious volume reduction effect.

[0040] Furthermore, when the sludge pyrolysis gas in the gas turbine reaches the combustion condition of the gas turbine as fuel, the delivery of air and natural gas is stopped, and the sludge pyrolysis gas is used to drive the gas turbine to generate electricity, thereby realizing the utilization of sludge energy resources, meeting the energy-saving and emission-reduction requirements of sludge treatment, and further improving energy utilization.

[0041] Furthermore, the sludge drying subsystem includes a sludge supply device, a drying device I, a gas-solid separation device I, a drying device II, and a gas-solid separation device II;

[0042] The sludge supply device inputs the sludge into the drying device I for drying, the dried sludge is separated from the flue gas, water vapor and some volatile gases in the gas-solid separation device I, the sludge is transported to the drying device II for secondary drying, the sludge after the secondary drying is separated from the flue gas, water vapor and some volatile gases again in the gas-solid separation device II, and the sludge after the secondary drying enters the pyrolysis gasification furnace for pyrolysis.

[0043] Furthermore, the gas turbine system also includes a flue gas purification device and an induced draft fan. The gas output ends of the gas-solid separation device I and the gas-solid separation device II are both connected to the flue gas purification device. The dried flue gas, water vapor and some volatile gases are purified in the flue gas purification device and then discharged into the atmosphere through the induced draft fan.

[0044] Furthermore, the high-temperature flue gas discharged by the gas turbine is transported to the drying device I and the waste heat utilization system, serving as heat sources for the drying device I and the drying device II, respectively.

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] 1. The simulation process combines two simplified methods (DRGEP+DRGPFA) to simplify the combustion reaction mechanism of the fuel in the gas turbine, identify, screen and eliminate unimportant components in the fuel, simplify the model to the greatest extent, obtain the simplified fuel mechanism, and minimize the error between the results of the simplified mechanism and the results of the detailed reaction mechanism, thereby improving the numerical calculation accuracy of the gas turbine combustion process and avoiding the phenomenon of inaccurate deletion of components and elementary reactions in the simplification process of the traditional single method.

[0047] 2. Through sensitivity analysis, the fuel combustion process is deeply explored to obtain the elementary reactions that have a greater impact on combustion and the degree of influence of these reactions on combustion emission pollutants. The present invention can make adjustments during the process of simplifying the mechanism model to ensure the reliability and accuracy of the model to the greatest extent, and effectively improve the efficiency of numerical calculation of combustion using chemical reaction mechanism coupled computational fluid model.

[0048] 3. Use sludge as energy for gas turbines. During the sludge drying process, volatile gases are treated by flue gas purification devices. After drying, the sludge is significantly reduced and stabilized, effectively avoiding groundwater pollution and environmental problems caused by sludge landfill and land use. Sludge pyrolysis kills microorganisms and produces usable resources. The exhaust gas emitted by the gas turbine is further recycled and used for sludge drying. The whole process not only solves the harmless treatment of sludge, but also reduces pollution emissions, achieving green and environmental protection.

[0049] 4. Using sludge pyrolysis gas as fuel during the combustion of gas turbines can not only achieve harmless, reduced, stabilized and resourceful treatment of sludge, but also use sludge as a flexible fuel to achieve low-pollution combustion technology for gas turbines. During the sludge drying process, volatile gases are treated by flue gas purification devices. Sludge pyrolysis and gasification can effectively destroy and kill pathogens. The organic components in the sludge are converted into combustible gas, high calorific value fuel oil and part of the fixed carbon, and the remaining part is converted into residue, with obvious volume reduction effect.

[0050] 5. The use of sludge pyrolysis gas to drive gas turbine power generation realizes the utilization of sludge energy resources, meets the energy conservation and emission reduction requirements of sludge treatment, and further improves energy utilization. The waste heat of gas turbine flue gas is used as the heat source for sludge drying, realizing energy cascade utilization, high thermal efficiency, saving fuel costs for sludge drying, realizing the recycling of working fluids, reducing duplicate construction, and having good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Simplified mechanistic flow diagram for gas turbine fuel combustion.

[0052] Figure 2 Schematic diagram of the gas turbine structure for burning sludge pyrolysis gas.

[0053] Figure 3 This is the simulation result of CO concentration emitted from pyrolysis gas of sludge combustion in gas turbine.

[0054] Figure 4 This is the simulation result of NO concentration emitted from pyrolysis gas of sludge combustion in gas turbine.

[0055] Figure 5 This is the simulation result of N2O concentration emitted from pyrolysis gas of sludge combustion in gas turbine.

[0056] Figure 6 This is the simulation result of HCl concentration emitted from pyrolysis gas of sludge combustion in gas turbine.

[0057] In the figure: 1-sludge supply device; 2-drying device I; 3-gas-solid separation device I; 4-drying device II; 5-gas-solid separation device II; 6-flue gas purification device; 7-induced draft fan; 8-pyrolysis gasification furnace; 9-gas turbine; 10-waste heat utilization system; 11-generator. DETAILED DESCRIPTION

[0058] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0059] See also Figure 1 The implementation method of the simplified combustion mechanism of sludge pyrolysis gas is described. A simplified fuel combustion mechanism method suitable for gas turbines combines the DRGEP and DRGPFA methods, including the following steps:

[0060] S1: Select the combustion model and its detailed reaction mechanism according to the fuel characteristics;

[0061] S2: The reaction mechanism was simplified using the DRGEP method to obtain simplified mechanism A;

[0062] S3: simplifying the simplified mechanism A using the DRGPFA method to obtain a simplified mechanism B;

[0063] S4: Perform sensitivity analysis on the simplified mechanism B;

[0064] S5: Verify the effectiveness of the simplified mechanism B. If it meets the requirements, output the simplified mechanism B. If it does not meet the requirements, optimize the detailed reaction mechanism and the simplified parameters of the DRGEP method and then re-execute step S2.

[0065] In step S1, the detailed reaction mechanism is a mechanism that is widely used and verified by a large number of experiments, or a chemical reaction mechanism that has been verified by experiments and is constructed in order to simulate and analyze the chemical composition in the actual fuel combustion process.

[0066] In step S1, the combustion model is selected from the PSR model in Chemkin.

[0067] In step S1, the detailed reaction mechanism is selected from the GRI-Mech3.0 mechanism for simulating methane combustion and the combustion mechanism for exploring the components in pyrolysis oil and pyrolysis gas.

[0068] The combustion mechanism used to explore the components in pyrolysis oil and pyrolysis gas is selected from the pyrolysis oil and gas combustion elementary reaction mechanism in Appendix B2 of the paper [Sun Yunan. Research on the migration characteristics of mercury in the process of co-pyrolysis / incineration of sludge and garbage and product utilization [D]. Tianjin University, 2020. DOI: 10.27356 / d.cnki.gtjdu.2020.000433.].

[0069] In step S2, the detailed mechanism model file of fuel combustion is imported into the Chemkin reactor for simplification.

[0070] In step S2, the DRGEP method is used to identify unimportant components and reactions in the detailed mechanism of the fuel, and finally the elementary reactions that have a certain influence on the characteristic quantity of fuel combustion are obtained, thereby forming a simplified mechanism A of the gas turbine fuel.

[0071] In step S2, CO, NO, N2O and HCl are set as key components, and the DRGEP method is used to identify unimportant components and reactions in the detailed reaction mechanism of the fuel. The error threshold of the simplification process is 20%, and finally the elementary reactions that have a certain influence on the characteristic quantity of fuel combustion are obtained, thereby forming a simplified mechanism A of the gas turbine fuel.

[0072] In step S2, the DRGEP method is further improved based on the simplification principle of the direct relationship graph method (DRG), and simplifies according to the overall impact of all components on each reaction path, starting from the target component, and finding the most important reaction path of each component, specifically:

[0073] The normalized contribution r of component A to the generation rate of component B is used AB To study the coupling relationship between component A and component B, the “R” value is used to determine the components stored in the mechanism. The “R” value also takes into account other components that can be obtained from these components through direct or indirect coupling, where r AB The formula with the "R" value is:

[0074]

[0075] In formula (1), P A and C A are the generation rate and consumption rate of component A, ν A,i is the stoichiometric coefficient of A, ω i is the production rate, δ i B The value of is 1 (the ith elementary reaction contains B) or 0. By presetting a series of important components and threshold ε, ε is compared with r AB The size of r ABWhen ε < ε, it means that the effect of component B on A can be ignored. Removing B from the mechanism will not cause a large error in A, and the corresponding components and reactions can be removed. AB When ≥ε, it means that the contribution of B to A is large enough, and removing B from the mechanism will cause a large error in the prediction of A, and the path relationship will be retained; in formula (2), S is the set of all possible paths from component A to B, r ij is the product of the weight chains along A under a given reaction path.

[0076] In step S3, the DRGPFA method is used to select important reaction paths using the production flux and consumption flux between reactions, so that the mechanism of the fuel in the model is simplified to the greatest extent, and a simplified mechanism B of the gas turbine fuel is obtained.

[0077] In step S3, the DRGPFA method is a new simplified method that combines the formation of DRG and the path flux method (PFA). The basic principle of this method is to replace the absolute reaction rate with the production flux and the consumption flux to identify the important reaction pathways, wherein the production flux P A With consumption flux C A The formula is (A represents substance A):

[0078]

[0079] In formula (3) and formula (4), ν A,i is the stoichiometric coefficient of A, ω i is the production rate.

[0080] In step S3, CO, NO, N2O and HCl are set as key components. The DRGPFA method is used to select important reaction paths using the production flux and consumption flux between reactions, so that the mechanism of the fuel in the model is simplified to the greatest extent. The error threshold of the simplification process is 20%, and the simplified mechanism B of the gas turbine fuel is obtained.

[0081] In step S3, the components in the fuel are identified, screened, and eliminated by the DRGEP+DRGPFA simplification method to simplify the model to the greatest extent and obtain a simplified mechanism B of the gas turbine fuel.

[0082] In step S4, the simplified mechanism B is analyzed by a sensitivity analysis method to obtain elementary reactions that have a certain influence on the combustion characteristic quantity.

[0083] In step S4, the sensitivity analysis method can deeply analyze the specific reactions that occur during the combustion process of the gas turbine fuel and the reactions that have a greater impact on the combustion process.

[0084] By screening the reactions whose absolute values ​​of the sensitivity coefficients are within the sensitivity coefficient range, the specific reactions that occur in the combustion process and the reactions that have a greater impact on the combustion process are obtained. The specific sensitivity coefficient range is: CO>0.015, NO>0.2, N2O>0.25, HCl>0.01.

[0085] In step S5, the effectiveness verification is specifically: comparative analysis is performed using the test data and the numerical calculation results of the simplified mechanism B. If the error is within 15%, it meets the requirements; if the error exceeds the set range (15%), it does not meet the requirements.

[0086] The detailed mechanism is a combustion mechanism selected from the reaction mechanisms of existing specific experiments, and this simplified mechanism has been verified in experiments, so the results of the simplified mechanism are consistent with those of the detailed mechanism and can be used in practical applications.

[0087] In step S5, the method for optimizing the detailed reaction mechanism includes: adjusting the pre-exponential factor of the elementary reaction based on the sensitivity coefficients of different reactions obtained by sensitivity analysis;

[0088] The method for adjusting the simplified parameters of the DRGEP method includes: adjusting the error threshold of the simplification process.

[0089] See also Figure 2 The embodiment of the gas turbine system for burning sludge pyrolysis gas for verifying the simplified combustion mechanism method of sludge pyrolysis gas according to claim 1 is described.

[0090] A gas turbine system for burning sludge pyrolysis gas, comprising a sludge drying subsystem, a pyrolysis gasification furnace 8, a gas turbine 9, a waste heat utilization system 10, a generator 11, and a flue gas purification device 6 and an induced draft fan 7;

[0091] The sludge drying subsystem comprises a sludge supply device 1, a drying device I 2, a gas-solid separation device I 3, a drying device II 4, and a gas-solid separation device II 5;

[0092] The sludge drying subsystem performs graded drying treatment on the sludge. The dried sludge is transported to the pyrolysis gasification furnace 8 for pyrolysis. The generated sludge pyrolysis gas is transported to the gas turbine 9 for combustion. The heat energy is converted into electrical energy in the generator 11. The high-temperature flue gas discharged by the gas turbine 9 provides a heat source for the sludge drying subsystem to dry the sludge.

[0093] The output end of the pyrolysis gasification furnace is connected to the input end of the gas turbine, the exhaust port of the gas turbine is connected to the heat source input end of the drying device I 2 and the waste heat utilization system 10 respectively, and the output end of the waste heat utilization system 10 is connected to the heat source input end of the drying device II 4;

[0094] The sludge input end of the drying device I 2 is connected to the sludge supply device 1, the output end of the drying device I 2 is connected to the input end of the gas-solid separation device I 3, the sludge output end of the gas-solid separation device I 3 is connected to the sludge input end of the drying device II 4, the output end of the drying device II 4 is connected to the input end of the gas-solid separation device II 5, the sludge output end of the gas-solid separation device II 5 is connected to the input end of the pyrolysis gasification furnace, and the gas output ends of the gas-solid separation device I 3 and the gas-solid separation device II 5 are both connected to the flue gas purification device 6;

[0095] The gas turbine 9 transports the high-temperature flue gas to the drying device I 2 and the waste heat utilization system 10, and the waste heat utilization system 10 transfers the heat to the drying device II 4, that is, the gas turbine 9 transports the discharged high-temperature flue gas to the drying device I 2 and the drying device II 4 to provide a heat source;

[0096] The sludge supply device 1 inputs the sludge into the drying device I 2 for drying. The dried sludge is separated from the flue gas, water vapor and some volatile gases in the gas-solid separation device I 3. The sludge is transported to the drying device II 4 for secondary drying. The secondary dried sludge is separated from the flue gas, water vapor and some volatile gases again in the gas-solid separation device II 5. The secondary dried sludge enters the pyrolysis gasification furnace 8 for pyrolysis.

[0097] The input end of the flue gas purification device 6 is connected to the gas output ends of the gas-solid separation device I 3 and the gas-solid separation device II 5. The dried flue gas, water vapor and volatile gas are purified in the flue gas purification device 6 and then discharged into the atmosphere through the induced draft fan 7.

[0098] When the pyrolysis gasification furnace pyrolyzes the sludge, the furnace temperature in the pyrolysis gasification furnace is 250°C-650°C, preferably 600°C, and the excess air coefficient is 0.2-0.6, preferably 0.2. Controlling the furnace temperature and oxygen intake can fully pyrolyze the organic components in the sludge.

[0099] Natural gas and air are also introduced into the gas turbine to burn together with the sludge pyrolysis gas. The sludge pyrolysis gasification can effectively destroy and kill pathogens, and the organic components in the sludge are converted into combustible gas, high calorific value fuel oil and part of the fixed carbon, and the remaining part is converted into residue, with obvious volume reduction effect.

[0100] When the sludge pyrolysis gas in the gas turbine reaches the combustion condition of the gas turbine as fuel, the delivery of air and natural gas is stopped, and the sludge pyrolysis gas is used to drive the gas turbine to generate electricity, thereby realizing the utilization of sludge energy resources, meeting the energy-saving and emission-reduction requirements of sludge treatment, and further improving energy utilization.

[0101] After the sludge is pyrolyzed in the pyrolysis gasifier 8, the obtained sludge pyrolysis gas is introduced into the gas turbine 9 and burned together with air and natural gas. The energy generated drives the generator 11 to do work, and the discharged high-temperature flue gas is output for reuse.

[0102] Combination Figure 2 To further illustrate this embodiment, the gas turbine 9 is introduced with air and natural gas, which are burned together with the sludge pyrolysis gas. The heat energy generated by the combustion drives the generator 11 to generate electricity. The high-temperature flue gas discharged after work is output to the drying device 12 and the waste heat utilization system 10, providing a heat source for sludge drying so as to recover the heat of the high-temperature flue gas. The flue gas waste heat of the gas turbine is used as a heat source for sludge drying, realizing energy cascade utilization, with high thermal efficiency, and saving the fuel cost of sludge drying.

[0103] The sludge is transported from the sludge supply device 1 to the drying device I 2, where the sludge is dried by heat exchange with the high-temperature flue gas, and the products are transported to the gas-solid separation device I 3 together. The water vapor, other volatile gases and the flue gas after heat exchange generated by the drying are separated and sent to the flue gas purification device 6 for treatment. The separated dried sludge enters the drying device II 4 for secondary drying. The heat source of the drying device II 4 is provided by the waste heat utilization system 10. The sludge is secondary dried in the drying device II 4. The water vapor, other volatile gases and the flue gas after heat exchange in the product after the secondary drying are separated by the gas-solid separation device II 5 and sent to the flue gas purification device 6 for treatment. The sludge after secondary drying is transported to the pyrolysis gasification furnace 8 for pyrolysis;

[0104] The sludge in the pyrolysis gasifier 8 is pyrolyzed into sludge pyrolysis gas, which enters the gas turbine 9 to burn and generate electricity, and the discharged high-temperature flue gas enters a new cycle.

[0105] Example 1

[0106] Combination Figure 1-Figure 6 The combustion mechanism simplification method of the present invention is further described:

[0107] S1: When the gas turbine uses sludge pyrolysis gas as fuel, the combustion mechanism with verified effectiveness is selected from the existing reaction mechanisms, which are the GRI-Mech3.0 mechanism mainly used to simulate methane combustion and the combustion mechanism used to explore the components in pyrolysis oil and pyrolysis gas. The two mechanisms are selected to consider the components more comprehensively. The two mechanisms are coupled as the detailed chemical reaction mechanism of sludge, and the chemical reaction kinetics is combined with other physical processes such as flow, heat transfer, and mass transfer to simulate the actual chemical process, so that the research on sludge combustion is more comprehensive. The detailed chemical reaction mechanism has a total of 75 components and 463 elementary reactions.

[0108] S2: The DRGEP method was used to simplify the detailed reaction mechanism. CO, NO, N2O and HCl were set as key components. The error threshold of the simplification process was 20%, and a simplified mechanism A with 39 components and 238 elementary reactions was obtained.

[0109] S3: The DRGPFA method was then used to further simplify the mechanism, setting CO, NO, N2O and HCl as key components with an error threshold of 20% for the simplification process, resulting in a simplified mechanism B consisting of 36 components and 208 elementary reactions.

[0110] S4: Use sensitivity analysis to determine the elementary reactions in simplified mechanism B that have the greatest impact on combustion temperature, and analyze the reactions that have the greatest impact on sludge during combustion.

[0111] By screening the reactions whose absolute values ​​of the sensitivity coefficients are within the sensitivity coefficient range, the specific reactions that occur in the combustion process and the reactions that have a greater impact on the combustion process are obtained. The specific sensitivity coefficient range is: CO>0.015, NO>0.2, N2O>0.25, HCl>0.01.

[0112] Through sensitivity analysis, it was found that in the simplified mechanism simulation of DRGEP+DRGPFA, the reactions OH+H2=H2O+H and H+O2=O+OH had significant effects on CO, NO, N2O, and HCl. In the combustion reaction, highly active free radicals, especially those in the form of -H and -OH groups, play a vital role in breaking molecular chemical bonds and promoting the combustion process. The simplified mechanism using the DRGEP+DRGPF method reduces the effect of the N element component on CO and retains the related reactions containing C elements that are sensitive to CO. The reactions with large sensitivity coefficients to NO in simplified mechanism B are NH2+NO=N2+H2O and NH2+NO=NNH+OH. The sensitivity coefficient of the sensitive reaction H+O2=O+OH to HCl remains at the maximum value.

[0113] S5: Verify the effectiveness of the simplified mechanism B: Compare and analyze the calculation results of the mechanism before simplification with the numerical calculation results of the simplified mechanism B.

[0114] Comparative Example 1

[0115] S1: When the gas turbine uses sludge pyrolysis gas as fuel, the combustion mechanisms that have been verified to be effective are selected from the existing reaction mechanisms, namely the GRI-Mech3.0 mechanism mainly used to simulate methane combustion, and the combustion mechanism used to explore the components in pyrolysis oil and pyrolysis gas. The two mechanisms are selected to consider the components more comprehensively. The two mechanisms are coupled as the detailed chemical reaction mechanism of sludge, which makes the study of sludge combustion more comprehensive. The detailed chemical reaction mechanism has a total of 75 components and 463 elementary reactions.

[0116] S2: The DRGEP method was used to simplify the detailed reaction mechanism, and a simplified mechanism M of 39 components and 238 elementary reactions was obtained.

[0117] S3: Verify the effectiveness of the simplified mechanism M: perform a comparative analysis between the calculation results of the mechanism before simplification and the numerical calculation results of the simplified mechanism M.

[0118] The effectiveness verification results of Example 1 and Comparative Example 1 are shown in Figure 3-Figure 6 As shown:

[0119] See also Figure 3 It can be seen that the CO concentration of the combustion emission pollutants after the simplified mechanism decreases with increasing temperature. Compared with the DRGEP method, the CO concentration of the DRGEP+DRGPFA method is slightly lower during the temperature increase, with a difference of about 10% from the DRGEP method, which is closer to the detailed mechanism simulation value, indicating that the simplified mechanism of the DRGEP+DRGPFA method can improve the calculation efficiency and make the simulation results more accurate.

[0120] See also Figure 4 and Figure 5 It can be seen that the concentration change trends and results of NO and N2O simulated by the DRGEP method and the DRGEP+DRGPFA method are basically consistent, and the difference with the results of the detailed mechanism simulation is less than 10%, indicating that the two simplified methods have little effect on the concentration results. Therefore, using the DRGEP+DRGPFA method to simulate not only reduces elementary reactions but also maintains a higher accuracy of the simulation.

[0121] See also Figure 6 It can be seen that for HCl concentration, the results obtained by the two simplified methods are exactly the same and consistent with the detailed mechanism.

[0122] Therefore, comparative analysis shows that the simplified mechanism simulation results of DRGEP+DRGPFA are very consistent with the detailed mechanism simulation results, indicating that the present invention is suitable for the simplified combustion mechanism method of gas turbines. The combustion mechanism simplification method of the present invention simplifies the sludge pyrolysis gas combustion mechanism, reduces elementary reactions, shortens the simulation time, and improves calculation efficiency. At the same time, the obtained results are basically consistent with the simulation results of the unsimplified mechanism (i.e., detailed mechanism). This shows that the simplified method of the present invention improves the numerical calculation accuracy and the numerical calculation efficiency of the working process in the simulation process of gas turbine combustion sludge pyrolysis gas, which can not only meet the numerical simulation requirements but also can be easily applied.

[0123] Compared with the DRGEP simplified method, the DRGEP+DRGPFA simplified method of the present invention further reduces the components and elementary reactions in the mechanism and improves the calculation efficiency. The results show that, compared with the DRGEP method, the simulation results of the present invention are closer to the simulation results of the detailed mechanism, indicating that the simplified method of the present invention can improve the calculation efficiency while making the simulation results more accurate.

[0124] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for simplifying the combustion mechanism of sludge pyrolysis gas, characterized in that: Combining DRGEP with DRGPFA method includes the following steps: S1: Select the combustion model and its detailed reaction mechanism according to the fuel characteristics; S2: The reaction mechanism was simplified using the DRGEP method to obtain simplified mechanism A; S3: simplifying the simplified mechanism A using the DRGPFA method to obtain a simplified mechanism B; S4: Perform sensitivity analysis on the simplified mechanism B; S5: Verify the effectiveness of the simplified mechanism B. If it meets the requirements, output the simplified mechanism B. If it does not meet the requirements, optimize the detailed reaction mechanism and the simplified parameters of the DRGEP method and then re-execute step S2.

2. The method for simplifying the combustion mechanism of sludge pyrolysis gas according to claim 1, characterized in that: In step S1, the combustion model is a Chemkin PSR model.

3. The method for simplifying the combustion mechanism of sludge pyrolysis gas according to claim 1, characterized in that: In step S1, the detailed reaction mechanism is selected from the GRI-Mech3.0 mechanism for simulating methane combustion and the combustion mechanism for exploring the components in pyrolysis oil and pyrolysis gas.

4. The method for simplifying the combustion mechanism of sludge pyrolysis gas according to claim 1, characterized in that: The effectiveness verification in step S5 is specifically: comparative analysis is performed using the test data and the numerical calculation results of the simplified mechanism B. If the error is within 15%, it meets the requirements; if the error exceeds 15%, it does not meet the requirements.

5. The method for simplifying the combustion mechanism of sludge pyrolysis gas according to claim 4, characterized in that: The method for optimizing the detailed reaction mechanism in step S5 includes: adjusting the pre-exponential factor of the elementary reaction based on the sensitivity coefficients of different reactions obtained by sensitivity analysis; The method for adjusting the simplified parameters of the DRGEP method includes: adjusting the error threshold of the simplification process.

6. A gas turbine system for burning sludge pyrolysis gas for verifying the simplified combustion mechanism method of sludge pyrolysis gas according to claim 1, characterized in that: It includes a sludge drying subsystem, a pyrolysis gasification furnace (8), a gas turbine (9), and a generator (11); The sludge drying subsystem performs graded drying treatment on the sludge. The dried sludge is transported to a pyrolysis gasification furnace (8) for pyrolysis. The generated sludge pyrolysis gas is transported to a gas turbine (9) for combustion. The heat energy is converted into electrical energy in a generator (11). The high-temperature flue gas emitted by the gas turbine (9) provides a heat source for the sludge drying subsystem to dry the sludge.

7. A gas turbine system for burning sludge pyrolysis gas according to claim 6, characterized in that: The furnace temperature in the pyrolysis gasification furnace (8) is 250°C-650°C, and the oxygen intake is 0.2-0.

6.

8. The gas turbine system for burning sludge pyrolysis gas according to claim 6, characterized in that: The sludge drying subsystem comprises a sludge supply device (1), a drying device I (2), a gas-solid separation device I (3), a drying device II (4), and a gas-solid separation device II (5); The sludge supply device (1) inputs the sludge into the drying device I (2) for drying. The dried sludge is separated from flue gas, water vapor and some volatile gases in the gas-solid separation device I (3). The sludge is transported to the drying device II (4) for secondary drying. The secondary dried sludge is separated from flue gas, water vapor and some volatile gases again in the gas-solid separation device II (5). The secondary dried sludge enters the pyrolysis gasification furnace (8) for pyrolysis.

9. A gas turbine system for burning sludge pyrolysis gas according to claim 8, characterized in that: The gas output ends of the gas-solid separation device I (3) and the gas-solid separation device II (5) are both connected to the flue gas purification device (6); the dried flue gas, water vapor and some volatile gases are purified in the flue gas purification device (6) and then discharged into the atmosphere through the induced draft fan (7).

10. The gas turbine system for burning sludge pyrolysis gas according to claim 6, characterized in that: The high-temperature flue gas discharged by the gas turbine (9) is transported to the drying device I (2) and the waste heat utilization system (10), and serves as heat sources for the drying device I (2) and the drying device II (4), respectively.

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