In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured resid...In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured residuals cannot isolate complex faults.This paper presents a multi-level strategy for complex fault isolation.An extraction procedure is employed to reduce the complex faults to simple ones and assign them to several levels.On each level,faults are isolated by their different responses in the structured residuals.Each residual is obtained insensitive to one fault but more sensitive to others.The faults on different levels are verified to have different residual responses and will not be confused.An entire incidence matrix containing residual response characteristics of all faults is obtained,based on which faults can be isolated.The proposed method is applied in the Tennessee Eastman process example,and the effectiveness and advantage are demonstrated.展开更多
This paper presents thermodynamic evaluations of the agriculture residual-to-SNG process by thermochemical conversion, which mainly consists of the interconnected fluidized beds, hot gas cleaning, fluidized bed methan...This paper presents thermodynamic evaluations of the agriculture residual-to-SNG process by thermochemical conversion, which mainly consists of the interconnected fluidized beds, hot gas cleaning, fluidized bed methanation reactor and Selexol absorption unit. The process was modeled using Aspen Plus soft-ware. The process performances, i.e., CH4 content in SNG~ higher heating value and yield of SNGexergy efficiencies with and without heat recovery, unit power consumption, were evaluated firstly. The results indicate that when the other parameters remain unchanged, the steam-to-biomass ratio at carbon boundary point is the optimal value for the process. Im proving the preheating temperatures of air and gasifying agent is beneficial for the SNG yield and exergy effi ciencies. Due to the effects of COz removal efficiency, there are two optimization objectives for the SNG produc tion process： （I） to maximize CH4 content in SNC or （II） to maximize SNG yield. Further, the comparison among different feedstocks indicates that the decreasing order of SNG yield is： corn stalk 〉 wheat straw 〉 rice straw. The evaluation on the potential of agriculture-based SNG shows that the potential annual production of agriculture re sidual-based SNG could be between 555 108 - 611 108 m3 with utilization of 100% of the available unexplored resources. The agriculture residual-based SNG could play a significant role on solving the big shortfall of China＇s natural gas supply in future.展开更多
基金Supported by the National Natural Science Foundation of China(60574047)the National High Technology Research and Development Program of China(2007AA04Z168,2009AA04Z154)the Research Fund for the Doctoral Program of Higher Education in China(20050335018)
文摘In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured residuals cannot isolate complex faults.This paper presents a multi-level strategy for complex fault isolation.An extraction procedure is employed to reduce the complex faults to simple ones and assign them to several levels.On each level,faults are isolated by their different responses in the structured residuals.Each residual is obtained insensitive to one fault but more sensitive to others.The faults on different levels are verified to have different residual responses and will not be confused.An entire incidence matrix containing residual response characteristics of all faults is obtained,based on which faults can be isolated.The proposed method is applied in the Tennessee Eastman process example,and the effectiveness and advantage are demonstrated.
基金supported by the Special Fund for Major State Basic Research Projects of China (2010CB732206, 2013CB228106)the Scientific Research Foundation of Graduate School of Southeast University (YBJJ1219)
文摘This paper presents thermodynamic evaluations of the agriculture residual-to-SNG process by thermochemical conversion, which mainly consists of the interconnected fluidized beds, hot gas cleaning, fluidized bed methanation reactor and Selexol absorption unit. The process was modeled using Aspen Plus soft-ware. The process performances, i.e., CH4 content in SNG~ higher heating value and yield of SNGexergy efficiencies with and without heat recovery, unit power consumption, were evaluated firstly. The results indicate that when the other parameters remain unchanged, the steam-to-biomass ratio at carbon boundary point is the optimal value for the process. Im proving the preheating temperatures of air and gasifying agent is beneficial for the SNG yield and exergy effi ciencies. Due to the effects of COz removal efficiency, there are two optimization objectives for the SNG produc tion process： （I） to maximize CH4 content in SNC or （II） to maximize SNG yield. Further, the comparison among different feedstocks indicates that the decreasing order of SNG yield is： corn stalk 〉 wheat straw 〉 rice straw. The evaluation on the potential of agriculture-based SNG shows that the potential annual production of agriculture re sidual-based SNG could be between 555 108 - 611 108 m3 with utilization of 100% of the available unexplored resources. The agriculture residual-based SNG could play a significant role on solving the big shortfall of China＇s natural gas supply in future.
