The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refri...The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refrigeration cycle operating with a hydrocarbon refrigerant. The hydrocarbon refrigerants considered are propane(R290), butane(R600), isobutane(R600a), and propylene(R1270). A computer program written in FORTRAN is developed to compute parameters for characteristic points of the cycles and the system's performance, which is determined and analyzed using numerical solutions for the refrigerant condensation temperature, temperature in tank, and temperature difference in the cascade condenser. Results show that R600 a gives the best performance, followed by(in order) R600, R290, and R1270. Furthermore, it is found that an increase in tank temperature improves system performance but that an increase in refrigerant condensation temperature causes deterioration. In addition, it is found that running the system at a low temperature difference in the cascade condenser is advantageous.展开更多
On the basis of the records of strong seismic events taking place in soft carbonate sediments, a new seismic sequence system of vibrational liquefaction is established, which consists of a series of units, such as esc...On the basis of the records of strong seismic events taking place in soft carbonate sediments, a new seismic sequence system of vibrational liquefaction is established, which consists of a series of units, such as escaped structure of micrite veins and liquefied deformation formed in the period of seismic liquefaction, land subsidence structure after liquefaction, tsunamic hummocky and turbidite produced by seismic events, This sequence is a generalization and summation of field observation in vast areas, which shows the whole process of a strong seismic event and provides an unified theoretical explanation. The pattern of the seismic sequence by vibrational liquefaction provides one of correlation standards for geologists in the field to discriminate events in carbonate sequences. Based on the pattern of seismic sequence, the authors first advance a new conception of the Palaeo-Tanlu (Tancheng-Lujiang) Zone and discuss primarily its geological significations.展开更多
BOG是储存在LNG罐时自然蒸发产生的气体(Boil Off Gas),一般利用氮气对BOG进行冷凝,然后将冷凝后的LNG重新回流输送到储罐中。本文选择以氮气为制冷剂采用逆布雷顿循环对BOG液化进行研究,分别对参与液化循环的设备进行建模并模拟了两种...BOG是储存在LNG罐时自然蒸发产生的气体(Boil Off Gas),一般利用氮气对BOG进行冷凝,然后将冷凝后的LNG重新回流输送到储罐中。本文选择以氮气为制冷剂采用逆布雷顿循环对BOG液化进行研究,分别对参与液化循环的设备进行建模并模拟了两种不同工况下的循环。通过计算分别给出BOG在不同温度时所对应的性能参数;通过改变氮气入口压力来分析不同液化循环的效率(COP),得出当减小氮气入口压力并控制氮气流速时整个液化循环的效率会提高,得出的结果对项目运行中BOG液化的成本控制有实际的借鉴意义。展开更多
文摘The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refrigeration cycle operating with a hydrocarbon refrigerant. The hydrocarbon refrigerants considered are propane(R290), butane(R600), isobutane(R600a), and propylene(R1270). A computer program written in FORTRAN is developed to compute parameters for characteristic points of the cycles and the system's performance, which is determined and analyzed using numerical solutions for the refrigerant condensation temperature, temperature in tank, and temperature difference in the cascade condenser. Results show that R600 a gives the best performance, followed by(in order) R600, R290, and R1270. Furthermore, it is found that an increase in tank temperature improves system performance but that an increase in refrigerant condensation temperature causes deterioration. In addition, it is found that running the system at a low temperature difference in the cascade condenser is advantageous.
基金A part of the results of the Project cosponsored by the Natural Scienee Fundation of China(49070127)the Chinese Academy of Geological Sciences(B8901)
文摘On the basis of the records of strong seismic events taking place in soft carbonate sediments, a new seismic sequence system of vibrational liquefaction is established, which consists of a series of units, such as escaped structure of micrite veins and liquefied deformation formed in the period of seismic liquefaction, land subsidence structure after liquefaction, tsunamic hummocky and turbidite produced by seismic events, This sequence is a generalization and summation of field observation in vast areas, which shows the whole process of a strong seismic event and provides an unified theoretical explanation. The pattern of the seismic sequence by vibrational liquefaction provides one of correlation standards for geologists in the field to discriminate events in carbonate sequences. Based on the pattern of seismic sequence, the authors first advance a new conception of the Palaeo-Tanlu (Tancheng-Lujiang) Zone and discuss primarily its geological significations.
文摘BOG是储存在LNG罐时自然蒸发产生的气体(Boil Off Gas),一般利用氮气对BOG进行冷凝,然后将冷凝后的LNG重新回流输送到储罐中。本文选择以氮气为制冷剂采用逆布雷顿循环对BOG液化进行研究,分别对参与液化循环的设备进行建模并模拟了两种不同工况下的循环。通过计算分别给出BOG在不同温度时所对应的性能参数;通过改变氮气入口压力来分析不同液化循环的效率(COP),得出当减小氮气入口压力并控制氮气流速时整个液化循环的效率会提高,得出的结果对项目运行中BOG液化的成本控制有实际的借鉴意义。
