采用热重分析法对锡林浩特相同粒度褐煤煤粉热解特性进行了热分析研究。根据实验数据,计算了燃烧反应速度峰值所对应的温度。褐煤粒度相同时,升温速率对最大重量损失速率的影响很大,随着升温速率的增加,TG曲线明显出现陡度减小,最大重...采用热重分析法对锡林浩特相同粒度褐煤煤粉热解特性进行了热分析研究。根据实验数据,计算了燃烧反应速度峰值所对应的温度。褐煤粒度相同时,升温速率对最大重量损失速率的影响很大,随着升温速率的增加,TG曲线明显出现陡度减小,最大重量损失速率增大,并且峰值温度有增加的趋势,挥发分析出明显提前,热解结束时间也明显提前,即热解反应更加容易发生;DTG峰值向高温区偏移。从实验数据得到煤热解的活化能分布值显示,锡林浩特褐煤活化能随着失重率的升高而增大,活化能处于230~500 k J/mol范围。展开更多
Currently,waste disposal has been highlighted strategically all over the world.Solid recovered fuel(SRF)with a high calorific value is manufactured from municipal solid waste(MSW).Thermogravimetric Fourier transform i...Currently,waste disposal has been highlighted strategically all over the world.Solid recovered fuel(SRF)with a high calorific value is manufactured from municipal solid waste(MSW).Thermogravimetric Fourier transform infrared spectroscopy(TG-FTIR)and distributed activation energy model(DAEM)were utilized to study the pyrolysis of the individual components and their mixture(i.e.SRF),which were obtained from a MSW incineration power plant.The best operating conditions were defined by comparing the effect of heating rates and flow rates of sweep gas.The gaseous products and functional groups in the pyrolysis of each component and their mixture were researched.Additionally,a direct search method was presented to obtain the DAEM kinetic parameters.DAEM equations for volatile products were given to describe pyrolysis of SRF.The model prediction results are consistent with the experimental results.The kinetic data will provide a basis for gas composition regulation from theoretical modeling.展开更多
Silicon-containing aryl acetylene resin(PSA)is a new type of high-temperature resistant resin with excellent oxidation resistance,whereas antioxidant reaction mechanism of PSA resin under ultra-high temperatures still...Silicon-containing aryl acetylene resin(PSA)is a new type of high-temperature resistant resin with excellent oxidation resistance,whereas antioxidant reaction mechanism of PSA resin under ultra-high temperatures still remains unclear.Herein,the oxidation behavior and mechanisms of PSA resin are systematically investigated combining kinetic analysis and Reax FF molecular dynamics(MD)simulations.Thermogravimetric analysis indicates that the oxidation process of PSA resin undergoes two main steps:oxidative mass gain and oxidative degradation.The distributed activation energy model(DAEM)is employed for describing oxidation processes and the best-fit one is obtained using genetic algorithms and differential evolution.DAEM model demonstrates that the oxidative weight gain stage is dominated by two virtual reactants and the oxidative degradation stage consists of three virtual reactants.Correspondingly,the observation of MD reaction pathways indicates that oxygen oxidation of unsaturated structures occurs in the initial stage,which results in the formation of PSA resin oxides.Furthermore,cracked pieces react with O_(2)to generate CO and other chemicals in the second step.The resin matrix's great antioxidation resilience is illustrated by the formation of SiO_(2).The analysis based on MD simulations exhibits an efficient computational proof with the experiments and DAEM methods.Based on the results,a two-stage reaction mechanism is proposed,which provides important theoretical support for the subsequent study of the oxidation behavior of silica-based resins.展开更多
The pyrolysis behaviors of Qingdao vacuum residue(QD-VR)and its SARA(saturates,aromatics,reins,and asphaltenes)fractions were evaluated by thermo-gravimetric with mass spectrometer(TG-MS).The pyrolysis kinetics were d...The pyrolysis behaviors of Qingdao vacuum residue(QD-VR)and its SARA(saturates,aromatics,reins,and asphaltenes)fractions were evaluated by thermo-gravimetric with mass spectrometer(TG-MS).The pyrolysis kinetics were determined by Friedman,one-parallel and four-parallel distributed activation energy model(DAEM),respectively.The results indicated that the pyrolysis behavior of QD-VR was similar to that of aromatics.For saturates,the release of H_(2),CH_(4),CO,and CO_(2) occurred in 80-400℃,while the temperature range for QD-VR and other fractions is 200-800℃.The average activation energy(Ea)via Friedman method was 179.72 kJ/mol and increased with the conversion ratio.One-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of the single SARA fractions,while four-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of heavy oil.Furthermore,comparing the weighted E_(a) from one-parallel(227.64 kJ/mol)and four-parallel Gaussian DAEM(204.63 kJ/mol),the results suggested that during pyrolysis process of heavy oil,there was an interaction between the SARA fractions,which could reduce the E_(a) of heavy oil pyrolysis.Specifically,during heavy oil pyrolysis,resins and asphaltenes could increase the E_(a) of saturates and aromatics,while saturates and aromatics could decrease the E_(a) of resins and asphaltenes.展开更多
文摘采用热重分析法对锡林浩特相同粒度褐煤煤粉热解特性进行了热分析研究。根据实验数据,计算了燃烧反应速度峰值所对应的温度。褐煤粒度相同时,升温速率对最大重量损失速率的影响很大,随着升温速率的增加,TG曲线明显出现陡度减小,最大重量损失速率增大,并且峰值温度有增加的趋势,挥发分析出明显提前,热解结束时间也明显提前,即热解反应更加容易发生;DTG峰值向高温区偏移。从实验数据得到煤热解的活化能分布值显示,锡林浩特褐煤活化能随着失重率的升高而增大,活化能处于230~500 k J/mol范围。
基金This research is supported by the National Key Research and Development Program of China(2018YFC1901302,2018YFF0215001,2017YFC0703100)the Innovative Research Groups of the National Natural Science Foundation of China(51621005)+1 种基金the National Natural Science Foundation of China(51676172)the Fundamental Research Funds for the Central Universities(No.2018FZA4010,2016FZA4010).
文摘Currently,waste disposal has been highlighted strategically all over the world.Solid recovered fuel(SRF)with a high calorific value is manufactured from municipal solid waste(MSW).Thermogravimetric Fourier transform infrared spectroscopy(TG-FTIR)and distributed activation energy model(DAEM)were utilized to study the pyrolysis of the individual components and their mixture(i.e.SRF),which were obtained from a MSW incineration power plant.The best operating conditions were defined by comparing the effect of heating rates and flow rates of sweep gas.The gaseous products and functional groups in the pyrolysis of each component and their mixture were researched.Additionally,a direct search method was presented to obtain the DAEM kinetic parameters.DAEM equations for volatile products were given to describe pyrolysis of SRF.The model prediction results are consistent with the experimental results.The kinetic data will provide a basis for gas composition regulation from theoretical modeling.
基金financially supported by National Natural Science Foundation of China(22008073,22078100,21878091)Shanghai Sailing Program(20YF1410600)。
文摘Silicon-containing aryl acetylene resin(PSA)is a new type of high-temperature resistant resin with excellent oxidation resistance,whereas antioxidant reaction mechanism of PSA resin under ultra-high temperatures still remains unclear.Herein,the oxidation behavior and mechanisms of PSA resin are systematically investigated combining kinetic analysis and Reax FF molecular dynamics(MD)simulations.Thermogravimetric analysis indicates that the oxidation process of PSA resin undergoes two main steps:oxidative mass gain and oxidative degradation.The distributed activation energy model(DAEM)is employed for describing oxidation processes and the best-fit one is obtained using genetic algorithms and differential evolution.DAEM model demonstrates that the oxidative weight gain stage is dominated by two virtual reactants and the oxidative degradation stage consists of three virtual reactants.Correspondingly,the observation of MD reaction pathways indicates that oxygen oxidation of unsaturated structures occurs in the initial stage,which results in the formation of PSA resin oxides.Furthermore,cracked pieces react with O_(2)to generate CO and other chemicals in the second step.The resin matrix's great antioxidation resilience is illustrated by the formation of SiO_(2).The analysis based on MD simulations exhibits an efficient computational proof with the experiments and DAEM methods.Based on the results,a two-stage reaction mechanism is proposed,which provides important theoretical support for the subsequent study of the oxidation behavior of silica-based resins.
基金the financial support of the National Natural Science Foundation(22278423,U1862107)Science Foundation of China University of Petroleum,Beijing(2462021QNXZ007).
文摘The pyrolysis behaviors of Qingdao vacuum residue(QD-VR)and its SARA(saturates,aromatics,reins,and asphaltenes)fractions were evaluated by thermo-gravimetric with mass spectrometer(TG-MS).The pyrolysis kinetics were determined by Friedman,one-parallel and four-parallel distributed activation energy model(DAEM),respectively.The results indicated that the pyrolysis behavior of QD-VR was similar to that of aromatics.For saturates,the release of H_(2),CH_(4),CO,and CO_(2) occurred in 80-400℃,while the temperature range for QD-VR and other fractions is 200-800℃.The average activation energy(Ea)via Friedman method was 179.72 kJ/mol and increased with the conversion ratio.One-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of the single SARA fractions,while four-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of heavy oil.Furthermore,comparing the weighted E_(a) from one-parallel(227.64 kJ/mol)and four-parallel Gaussian DAEM(204.63 kJ/mol),the results suggested that during pyrolysis process of heavy oil,there was an interaction between the SARA fractions,which could reduce the E_(a) of heavy oil pyrolysis.Specifically,during heavy oil pyrolysis,resins and asphaltenes could increase the E_(a) of saturates and aromatics,while saturates and aromatics could decrease the E_(a) of resins and asphaltenes.
