Ethylene cracking process is the core production process in ethylene industry,and is paid more attention to reduce high energy consumption.Because of the interdependent relationships between multi-flow allocation and ...Ethylene cracking process is the core production process in ethylene industry,and is paid more attention to reduce high energy consumption.Because of the interdependent relationships between multi-flow allocation and multi-parameter setting in cracking process,it is difficult to find the overall energy efficiency scheduling for the purpose of saving energy.The traditional scheduling solutions with optimal economic benefit are not applicable for energy efficiency scheduling issue due to the neglecting of recycle and lost energy,as well as critical operation parameters as coil outlet pressure(COP)and dilution ratio.In addition,the scheduling solutions mostly regard each cracking furnace as an elementary unit,regardless of the coordinated operation of internal dual radiation chambers(DRC).Therefore,to improve energy utilization and production operation,a novel energy efficiency scheduling solution for ethylene cracking process is proposed in this paper.Specifically,steam heat recycle and exhaust heat loss are considered in cracking process based on 6 types of extreme learning machine(ELM)based cracking models incorporating DRC operation and three operation parameters as coil outlet temperature(COT),COP,and dilution ratio according to semi-mechanism analysis.Then to provide long-term decision-making basis for energy efficiency scheduling,overall energy efficiency indexes,including overall output per unit net energy input(OONE),output-input ratio per unit net energy input(ORNE),exhaust gas heat loss ratio(EGHL),are designed based on input-output analysis in terms of material and energy flows.Finally,a multiobjective evolutionary algorithm based on decomposition(MOEA/D)is employed to solve the formulated multi-objective mixed-integer nonlinear programming(MOMINLP)model.The validities of the proposed scheduling solution are illustrated through a case study.The scheduling results demonstrate that an optimal balance between multi-flow allocation,multi-parameter setting,and DRC coordinated operation is reached,which achieves 3.37%and 2.63%decreases in net energy input for same product output and conversion ratio,as well as the 1.56%decrease in energy loss ratio.展开更多
目的比较青春发育期体重正常和肥胖儿童青少年身体成分、非脂肪组织指数（fat-free mass index，FFMI）和脂肪组织指数（fat mass index，FMI）及其随年龄变化趋势和性别差异。方法选择7～15岁体重正常和肥胖儿童356名，每组各性别、年...目的比较青春发育期体重正常和肥胖儿童青少年身体成分、非脂肪组织指数（fat-free mass index，FFMI）和脂肪组织指数（fat mass index，FMI）及其随年龄变化趋势和性别差异。方法选择7～15岁体重正常和肥胖儿童356名，每组各性别、年龄约10名，采用DEXA法测定身体成分，根据公式FFMI（kg·m^-2）=非脂肪组织（FFM）（kg）／身高（m）^2，FMI（kg·m^-2）=脂肪组织（FM）（kg）／身高（m）^2计算FFMI和FMI。结果各年龄组男、女生肥胖儿童身体成分中脂肪组织和去脂肪组织的实测值均高于体重正常儿童（P〈0．05）。7～15岁肥胖儿童FFMI和FMI均随年龄增长而增加，并高于同性别、同年龄组体重正常儿童，差异有统计学意义（P〈0．05）。结论肥胖儿童脂肪组织、去脂肪组织含量、FFMI、FMI，与体重正常儿童存在差异，男女间差异明显；FFMI和FMI是肥胖儿童的体重管理中值得应用的监测指标。展开更多
基金supported by the High-tech Research and Development Program of China(2014AA041802)。
文摘Ethylene cracking process is the core production process in ethylene industry,and is paid more attention to reduce high energy consumption.Because of the interdependent relationships between multi-flow allocation and multi-parameter setting in cracking process,it is difficult to find the overall energy efficiency scheduling for the purpose of saving energy.The traditional scheduling solutions with optimal economic benefit are not applicable for energy efficiency scheduling issue due to the neglecting of recycle and lost energy,as well as critical operation parameters as coil outlet pressure(COP)and dilution ratio.In addition,the scheduling solutions mostly regard each cracking furnace as an elementary unit,regardless of the coordinated operation of internal dual radiation chambers(DRC).Therefore,to improve energy utilization and production operation,a novel energy efficiency scheduling solution for ethylene cracking process is proposed in this paper.Specifically,steam heat recycle and exhaust heat loss are considered in cracking process based on 6 types of extreme learning machine(ELM)based cracking models incorporating DRC operation and three operation parameters as coil outlet temperature(COT),COP,and dilution ratio according to semi-mechanism analysis.Then to provide long-term decision-making basis for energy efficiency scheduling,overall energy efficiency indexes,including overall output per unit net energy input(OONE),output-input ratio per unit net energy input(ORNE),exhaust gas heat loss ratio(EGHL),are designed based on input-output analysis in terms of material and energy flows.Finally,a multiobjective evolutionary algorithm based on decomposition(MOEA/D)is employed to solve the formulated multi-objective mixed-integer nonlinear programming(MOMINLP)model.The validities of the proposed scheduling solution are illustrated through a case study.The scheduling results demonstrate that an optimal balance between multi-flow allocation,multi-parameter setting,and DRC coordinated operation is reached,which achieves 3.37%and 2.63%decreases in net energy input for same product output and conversion ratio,as well as the 1.56%decrease in energy loss ratio.
文摘目的比较青春发育期体重正常和肥胖儿童青少年身体成分、非脂肪组织指数（fat-free mass index，FFMI）和脂肪组织指数（fat mass index，FMI）及其随年龄变化趋势和性别差异。方法选择7～15岁体重正常和肥胖儿童356名，每组各性别、年龄约10名，采用DEXA法测定身体成分，根据公式FFMI（kg·m^-2）=非脂肪组织（FFM）（kg）／身高（m）^2，FMI（kg·m^-2）=脂肪组织（FM）（kg）／身高（m）^2计算FFMI和FMI。结果各年龄组男、女生肥胖儿童身体成分中脂肪组织和去脂肪组织的实测值均高于体重正常儿童（P〈0．05）。7～15岁肥胖儿童FFMI和FMI均随年龄增长而增加，并高于同性别、同年龄组体重正常儿童，差异有统计学意义（P〈0．05）。结论肥胖儿童脂肪组织、去脂肪组织含量、FFMI、FMI，与体重正常儿童存在差异，男女间差异明显；FFMI和FMI是肥胖儿童的体重管理中值得应用的监测指标。
