Mathematical models of steady-state biofilteration are discussed. The theoretical results are much useful for the design of biofilters. This model is based on the system of non-linear reaction/diffusion equations cont...Mathematical models of steady-state biofilteration are discussed. The theoretical results are much useful for the design of biofilters. This model is based on the system of non-linear reaction/diffusion equations contains a non-linear term related to Monod kinetics, Andrews kinetics, interactive model from Monod kinetics and Andrews kinetics. Analytical expression of concentration of VOC (Volatile organic compounds) and oxygen are derived by solving the system of non-linear equations using Adomian decomposition method (ADM) method. Our analytical results are also compared with the simulation results. Satisfactory agreement is noted.展开更多
Based on use of multi-dimensional models,this investigation simulates the performance of a proton exchange membrane fuel cell by varying the channel pattern.In the one-dimensional model,the porosity of the gas diffusi...Based on use of multi-dimensional models,this investigation simulates the performance of a proton exchange membrane fuel cell by varying the channel pattern.In the one-dimensional model,the porosity of the gas diffusion layer is 0.3.The model reveals the water vapor distribution of the fuel cell and demonstrates that the amount of water vapor increases linearly with the reduction reaction adjacent to the gas channel and the gas diffusion layer.Secondly,four novel tapered gas channels are simulated by a two-dimensional model.The model considers the distributions of oxygen,the pressure drop,the amount of water vapor distribution and the polarization curves.The results indicate that as the channel depth decreases,the oxygen in the tapered gas channel can be accel-erated and forced into the gas diffusion layer to improve the cell performance.The three-dimensional model is employed to simulate the phenomenon associated with four novel tapered gas channels.The results also show that the best performance is realized in the least tapered gas channel.Finally,an experimentally determined mechanism is found to be consistent with the results of the simulation.展开更多
船用燃油成本一直都在航次成本中占有较大的比重,加强对船用燃油价格波动的监控和预测是航运企业加强经营成本控制和管理的重要手段。以新加坡市场船用燃油IFO380cst作为研究对象,利用ARMA(1,1)模型对其价格收益率进行回归拟合,通过GARC...船用燃油成本一直都在航次成本中占有较大的比重,加强对船用燃油价格波动的监控和预测是航运企业加强经营成本控制和管理的重要手段。以新加坡市场船用燃油IFO380cst作为研究对象,利用ARMA(1,1)模型对其价格收益率进行回归拟合,通过GARCH模型消除了序列存在的异方差性,并利用GARCH-M模型和TARCH模型对其进行进一步研究,发现对于新加坡市场船用燃油IFO380cst而言,不存在ARCH in mean效应和杠杆效应。展开更多
在燃煤电站整合氧热法生产电石的技术工艺路线中,电石反应器串接在锅炉炉膛前,采用干燥煤粉、石灰粉和氧气作为反应原料,反应副产物烟气和含未燃碳的飞灰送入锅炉炉膛放热并燃烧,回收其热能与化学能。基于热力学原理构建化学反应的热平...在燃煤电站整合氧热法生产电石的技术工艺路线中,电石反应器串接在锅炉炉膛前,采用干燥煤粉、石灰粉和氧气作为反应原料,反应副产物烟气和含未燃碳的飞灰送入锅炉炉膛放热并燃烧,回收其热能与化学能。基于热力学原理构建化学反应的热平衡模型,计算产出电石纯度、原料耗量和电耗、能量的利用和回收情况,并探讨变换反应原料对上述参数的影响。结果表明:煤粉氧热法产出的电石纯度为65.97%,每生产1t Ca C2,消耗煤粉1747.08kg,石灰粉980.5kg,氧气1285.25m3,电耗554.28k W·h;提高氧气纯度,各量变化十分微小,而制氧电耗大幅上升,采用不同煤种,各量的变化比较显著。论证了燃煤电站氧热法联产电石工艺的可行性,并为实际生产中原料的选取提供了理论指导。展开更多
文摘Mathematical models of steady-state biofilteration are discussed. The theoretical results are much useful for the design of biofilters. This model is based on the system of non-linear reaction/diffusion equations contains a non-linear term related to Monod kinetics, Andrews kinetics, interactive model from Monod kinetics and Andrews kinetics. Analytical expression of concentration of VOC (Volatile organic compounds) and oxygen are derived by solving the system of non-linear equations using Adomian decomposition method (ADM) method. Our analytical results are also compared with the simulation results. Satisfactory agreement is noted.
基金Supported by the National Science Council (NSC 97-222-E-009-067)
文摘Based on use of multi-dimensional models,this investigation simulates the performance of a proton exchange membrane fuel cell by varying the channel pattern.In the one-dimensional model,the porosity of the gas diffusion layer is 0.3.The model reveals the water vapor distribution of the fuel cell and demonstrates that the amount of water vapor increases linearly with the reduction reaction adjacent to the gas channel and the gas diffusion layer.Secondly,four novel tapered gas channels are simulated by a two-dimensional model.The model considers the distributions of oxygen,the pressure drop,the amount of water vapor distribution and the polarization curves.The results indicate that as the channel depth decreases,the oxygen in the tapered gas channel can be accel-erated and forced into the gas diffusion layer to improve the cell performance.The three-dimensional model is employed to simulate the phenomenon associated with four novel tapered gas channels.The results also show that the best performance is realized in the least tapered gas channel.Finally,an experimentally determined mechanism is found to be consistent with the results of the simulation.
文摘船用燃油成本一直都在航次成本中占有较大的比重,加强对船用燃油价格波动的监控和预测是航运企业加强经营成本控制和管理的重要手段。以新加坡市场船用燃油IFO380cst作为研究对象,利用ARMA(1,1)模型对其价格收益率进行回归拟合,通过GARCH模型消除了序列存在的异方差性,并利用GARCH-M模型和TARCH模型对其进行进一步研究,发现对于新加坡市场船用燃油IFO380cst而言,不存在ARCH in mean效应和杠杆效应。
文摘在燃煤电站整合氧热法生产电石的技术工艺路线中,电石反应器串接在锅炉炉膛前,采用干燥煤粉、石灰粉和氧气作为反应原料,反应副产物烟气和含未燃碳的飞灰送入锅炉炉膛放热并燃烧,回收其热能与化学能。基于热力学原理构建化学反应的热平衡模型,计算产出电石纯度、原料耗量和电耗、能量的利用和回收情况,并探讨变换反应原料对上述参数的影响。结果表明:煤粉氧热法产出的电石纯度为65.97%,每生产1t Ca C2,消耗煤粉1747.08kg,石灰粉980.5kg,氧气1285.25m3,电耗554.28k W·h;提高氧气纯度,各量变化十分微小,而制氧电耗大幅上升,采用不同煤种,各量的变化比较显著。论证了燃煤电站氧热法联产电石工艺的可行性,并为实际生产中原料的选取提供了理论指导。
