This paper focuses on the mixed-refrigerant refrigeration process flows which are applied in the cryogenic separation section of ethylene plant. Based on a 120 kt/a ethylene plant which employs a sequence separation p...This paper focuses on the mixed-refrigerant refrigeration process flows which are applied in the cryogenic separation section of ethylene plant. Based on a 120 kt/a ethylene plant which employs a sequence separation process flow and lowpressure demethanization system, the energy consumption of three refrigeration process flows（typical cascade refrigeration, binary refrigeration and tertiary refrigeration） was calculated by means of the ASPEN PLUS simulation software. An optimized mixed-refrigerant composition which achieved the minimum energy consumption of refrigeration systems was found out and the exergy loss was analyzed and compared. Results indicated that the energy consumption of typical cascade refrigeration and binary refrigeration systems was almost equal and that of tertiary refrigeration system was higher than the other two systems. Based on the current situation of production, the suggestions on production optimization and refrigeration process flow selection were put forward.展开更多
To better improve the emergency communication and location-based services of disaster information reporting network for serious natural response and relieL disaster emergency the national natural disaster reduction ap...To better improve the emergency communication and location-based services of disaster information reporting network for serious natural response and relieL disaster emergency the national natural disaster reduction application platform based on BeiDou navigation satellite system is constructed. The administrative distributed platform is integrated with BeiDou positioning and multiple communication ways so as to achieve main disaster reduction application services, including disaster information acquisition and monitoring, emergency relief for trapped people, on-site emergency relief command service, relief supplies＇ transportation monitoring, and disaster information publishing service. By the platform, serious disaster information reporting time may be reduced to one hour and the emergency decision-making information service for serious natural disasters can be effectively improved, and it will be helpful to provide technical references for the industrial application and promotion of BeiDou inte- grated disaster reduction.展开更多
To analyze and reduce the impact of Machine-to-Machine (M2M) Devices (MDs) on the traditional Human-to-Human (H2H) users for the blending scenario, where both M2M and H2H services coexist in the current Universal Mobi...To analyze and reduce the impact of Machine-to-Machine (M2M) Devices (MDs) on the traditional Human-to-Human (H2H) users for the blending scenario, where both M2M and H2H services coexist in the current Universal Mobile Telecommunication System (UMTS) and perform the Random Access (RA) procedure simultaneously, a comprehensive RA analysis model of RA is proposed in this paper. Further, a power ramping strategy based on the logarithm for M2M is proposed. The efficiency of both the existing and proposed scheme is assessed through a simulation across several metrics, including average target power, throughput, blocking probability, and delay statistics. Numerical results show that the proposed algorithm can ensure a minimal impact on H2H communication while maintaining the throughput of the M2M communication. Meanwhile, because of its low energy consumption, this algorithm has a significant guide value for real-world applications.展开更多
文摘This paper focuses on the mixed-refrigerant refrigeration process flows which are applied in the cryogenic separation section of ethylene plant. Based on a 120 kt/a ethylene plant which employs a sequence separation process flow and lowpressure demethanization system, the energy consumption of three refrigeration process flows（typical cascade refrigeration, binary refrigeration and tertiary refrigeration） was calculated by means of the ASPEN PLUS simulation software. An optimized mixed-refrigerant composition which achieved the minimum energy consumption of refrigeration systems was found out and the exergy loss was analyzed and compared. Results indicated that the energy consumption of typical cascade refrigeration and binary refrigeration systems was almost equal and that of tertiary refrigeration system was higher than the other two systems. Based on the current situation of production, the suggestions on production optimization and refrigeration process flow selection were put forward.
基金supported by National Bei Dou Special Project and National Science & Technology planning project of China (Grant No. 2014BAK12B04)
文摘To better improve the emergency communication and location-based services of disaster information reporting network for serious natural response and relieL disaster emergency the national natural disaster reduction application platform based on BeiDou navigation satellite system is constructed. The administrative distributed platform is integrated with BeiDou positioning and multiple communication ways so as to achieve main disaster reduction application services, including disaster information acquisition and monitoring, emergency relief for trapped people, on-site emergency relief command service, relief supplies＇ transportation monitoring, and disaster information publishing service. By the platform, serious disaster information reporting time may be reduced to one hour and the emergency decision-making information service for serious natural disasters can be effectively improved, and it will be helpful to provide technical references for the industrial application and promotion of BeiDou inte- grated disaster reduction.
基金supported in part by the National Natural Science Foundation of Chinaunder Grants No.60971125, No.61121001Major National S&T Project under Grant No. 2012ZX03005010 the project under Grant No.201105
文摘To analyze and reduce the impact of Machine-to-Machine (M2M) Devices (MDs) on the traditional Human-to-Human (H2H) users for the blending scenario, where both M2M and H2H services coexist in the current Universal Mobile Telecommunication System (UMTS) and perform the Random Access (RA) procedure simultaneously, a comprehensive RA analysis model of RA is proposed in this paper. Further, a power ramping strategy based on the logarithm for M2M is proposed. The efficiency of both the existing and proposed scheme is assessed through a simulation across several metrics, including average target power, throughput, blocking probability, and delay statistics. Numerical results show that the proposed algorithm can ensure a minimal impact on H2H communication while maintaining the throughput of the M2M communication. Meanwhile, because of its low energy consumption, this algorithm has a significant guide value for real-world applications.
