This work is focused on the performance prediction of pilot scale catalytic reverse flow reactors used for combustion of lean methane-air mixtures. An unsteady one-dimensional heterogeneous model for the reactor was e...This work is focused on the performance prediction of pilot scale catalytic reverse flow reactors used for combustion of lean methane-air mixtures. An unsteady one-dimensional heterogeneous model for the reactor was established to account for the influence of the reactor wall on the heat transfer. Results of the simulation indicate that feed concentration, switch time and compensatory temperature impose important influence on the performance of the reactor. The amount of the heat extracted from the mid-section of the reactor can be optimized via adjusting the parameters mentioned above. At the optimal operating conditions, Le. switching time of 400 s, feed concentration of 1% （by volume）, and insulation layer temperature of 343 K, the axial temperature of the reactor revealed a comparatively symmetrical ＂saddle＂ distribution, indicating a favorable operating status of the catalytic reverse flow reactor.展开更多
The control system of a catalytic flow reversal reactor （CFRR） for the mitigation of ventilation air methane was investigated. A one-dimensional heteroge- neous model with a logic-based controller was applied to sim...The control system of a catalytic flow reversal reactor （CFRR） for the mitigation of ventilation air methane was investigated. A one-dimensional heteroge- neous model with a logic-based controller was applied to simulate the CFRR. The simulation results indicated that the controller developed in this work performs well under normal conditions. Air dilution and auxiliary methane injection are effective to avoid the catalyst overheating and reaction extinction caused by prolonged rich and lean feed conditions, respectively. In contrast, the reactor is prone to lose control by adjusting the switching time solely. Air dilution exhibits the effects of two contradictory aspects on the operation of CFRR, i.e., cooling the bed and accumulating heat, though the former is in general more prominent. Lowering the reference temperature for flow reversal can decrease the bed temperature and benefit stable operation under rich methane feed condition.展开更多
The catalytic combustion of low concentration methane was systematically investigated in a pilot scale reverse flow reactor.The influences of cyclic period,the concentration of reactant and the space velocity on the o...The catalytic combustion of low concentration methane was systematically investigated in a pilot scale reverse flow reactor.The influences of cyclic period,the concentration of reactant and the space velocity on the operation performance of reactor were studied.The experimental results showed that,for the reverse flow reactor,cyclic period,the concentration of reactant and the space velocity were three important operation parameters that obviously affected the axial temperature profiles of reactor.It′s possible to maintain autothermal operation with high conversion of methane even though the methane concentration decreased to 0.5%.When the methane concentration was increased up to 0.8%,the highest temperature of catalyst bed was beyond 700 ℃.It suggests that the energy of the hot gas should be recovered and this reactive technology is able to be used in power production with low concentration methane.展开更多
This paper reviews the research progress in catalytic combustion technology with reversal flow for detoxicating the volatile organic compounds (VOCs) from industry waste gases. The applicable fields of this technology...This paper reviews the research progress in catalytic combustion technology with reversal flow for detoxicating the volatile organic compounds (VOCs) from industry waste gases. The applicable fields of this technology, the advantages over other technologies and its progresses in experimental investigation and modeling study are mainly introduced. Operation stability of the fixed_bed reactor with reversal flow and its improvement are briefly discussed, also.展开更多
基金Supported by the National High Technology Research and Development Program of China(2006AA030201)
文摘This work is focused on the performance prediction of pilot scale catalytic reverse flow reactors used for combustion of lean methane-air mixtures. An unsteady one-dimensional heterogeneous model for the reactor was established to account for the influence of the reactor wall on the heat transfer. Results of the simulation indicate that feed concentration, switch time and compensatory temperature impose important influence on the performance of the reactor. The amount of the heat extracted from the mid-section of the reactor can be optimized via adjusting the parameters mentioned above. At the optimal operating conditions, Le. switching time of 400 s, feed concentration of 1% （by volume）, and insulation layer temperature of 343 K, the axial temperature of the reactor revealed a comparatively symmetrical ＂saddle＂ distribution, indicating a favorable operating status of the catalytic reverse flow reactor.
文摘The control system of a catalytic flow reversal reactor （CFRR） for the mitigation of ventilation air methane was investigated. A one-dimensional heteroge- neous model with a logic-based controller was applied to simulate the CFRR. The simulation results indicated that the controller developed in this work performs well under normal conditions. Air dilution and auxiliary methane injection are effective to avoid the catalyst overheating and reaction extinction caused by prolonged rich and lean feed conditions, respectively. In contrast, the reactor is prone to lose control by adjusting the switching time solely. Air dilution exhibits the effects of two contradictory aspects on the operation of CFRR, i.e., cooling the bed and accumulating heat, though the former is in general more prominent. Lowering the reference temperature for flow reversal can decrease the bed temperature and benefit stable operation under rich methane feed condition.
文摘The catalytic combustion of low concentration methane was systematically investigated in a pilot scale reverse flow reactor.The influences of cyclic period,the concentration of reactant and the space velocity on the operation performance of reactor were studied.The experimental results showed that,for the reverse flow reactor,cyclic period,the concentration of reactant and the space velocity were three important operation parameters that obviously affected the axial temperature profiles of reactor.It′s possible to maintain autothermal operation with high conversion of methane even though the methane concentration decreased to 0.5%.When the methane concentration was increased up to 0.8%,the highest temperature of catalyst bed was beyond 700 ℃.It suggests that the energy of the hot gas should be recovered and this reactive technology is able to be used in power production with low concentration methane.
文摘This paper reviews the research progress in catalytic combustion technology with reversal flow for detoxicating the volatile organic compounds (VOCs) from industry waste gases. The applicable fields of this technology, the advantages over other technologies and its progresses in experimental investigation and modeling study are mainly introduced. Operation stability of the fixed_bed reactor with reversal flow and its improvement are briefly discussed, also.
