Coupling Characteristics Of Methane-carbon Dioxide Reforming Thermochemical Recovery Of Flue Gas Waste Heat

Among the main raw materials of fossil fuels,the proportion of natural gas is increasing year by year.The main component is the main greenhouse gas methane,and carbon dioxide is also excessively emitted with the increase in natural gas utilization,leading to the greenhouse effect.Nowadays,the waste heat emission in the chemical process has not yet achieved the purpose of saving energy in terms of economy and utilization rate.Therefore,this paper proposes a coupled system using methane-carbon dioxide reforming reaction for waste heat recovery.By studying the optimal conditions of methane-carbon dioxide reforming reaction,the optimal energy matching relationship between methane combustion and methane-carbon dioxide reforming coupled system is calculated and analyzed.To achieve the maximum use of energy.Methane and carbon dioxide are typical greenhouse gases as well as important carbon-containing resources.Combining the two can save energy while eliminating the greenhouse effect.Compared with waste heat boilers,it is also adaptable,has high recovery efficiency,and can reduce a certain amount.The advantage of the amount of carbon emissions.Firstly,select the reaction temperature of the methane-carbon dioxide reforming reaction by thermodynamic method,and then use Aspen Plus to simulate and analyze the feasibility of the methane-carbon dioxide reforming system,and use single factor variables to find the optimal reaction temperature and reaction of the methane-carbon dioxide reforming reaction.The pressure and intake air ratio are verified by experiments to verify whether the simulation changes in the methane-carbon dioxide reforming reaction are correct.Finally,the coupling of the methane-carbon dioxide reforming reaction and methane combustion is calculated by calculating the reaction heat and thermochemical energy storage efficiency.The system performs heat matching calculation and obtains the best energy matching relationship of the system.The specific conclusions are as follows:1.The spontaneous reaction temperature of the methane-carbon dioxide reforming reaction is above 641°C.In the side reaction,the reverse water gas shift reaction can eliminate carbon deposits.The spontaneous reaction temperature is above 555°C.The carbon monoxide disproportionation reaction will produce carbon deposits.The spontaneous reaction temperature is below 700°C.In summary,it is concluded that the optimal temperature for the methane-carbon dioxide reforming reaction is above 700°C.2.The results obtained by Aspen Plus simulation:low pressure is beneficial for the methane-carbon dioxide reforming reaction to proceed in the positive direction,the smaller the amount of reactant methane,the greater the methane conversion rate,while the change trend of the carbon dioxide conversion rate is opposite;this system is reacting When the pressure is 1 atm,the reaction temperature is 900?,and the CO₂/CH₄ value is 3,the methane conversion rate reaches 99.94%.3.Under the conditions of a pressure of 1atm,a total inlet flow of 200ml/min,a temperature of 850?and a CH₄:CO₂:N₂=1:1:0.5,the conversion rates of methane and carbon dioxide reached 97.63%and 98.21%,respectively,hydrogen and carbon monoxide The selectivity of the gas also reached 94.42%and 97.89%,respectively.The H₂/CO value of the synthesis gas increased with the increase of temperature.4.When the temperature of the methane-carbon dioxide reforming reaction is higher than 850?,the reaction heat tends to be stable when CH₄/CO₂=1/3,reaching 275.5 k Jmol-1.It can be concluded that the temperature increase is beneficial to the reaction before 850?The law of heat increase.When the pressure of the methane-carbon dioxide reforming waste heat recovery system is 1atm,the temperature is 850?,and the CO₂/CH₄ value is 3,the heat conversion rate is 131.16%.At 1atm,850?,and CH₄/CO₂=1/3,the methane-carbon dioxide reforming reaction recovery system can reach the maximum exhaust gas thermochemical recovery,and the exhaust gas heat discharged by the system at this time is52.62k J/mol.The research results of this paper provide a theoretical basis for the actual process of the coupled system of methane-carbon dioxide reforming waste heat recovery in the future,and have a certain guiding role.