Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power gen...Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.展开更多
In recent years, introduction of alternative energy sources such as solar energy is expected. Solar heat energy utilization systems are rapidly gaining acceptance as one of the best solutions to be an alternative ener...In recent years, introduction of alternative energy sources such as solar energy is expected. Solar heat energy utilization systems are rapidly gaining acceptance as one of the best solutions to be an alternative energy source. However, thermal energy collection is influenced by solar radiation and weather conditions. In order to control a solar heat energy utilization system as accurate as possible, it requires method of solar radiation estimation. This paper proposes the forecast technique of a thermal energy collection of solar heat energy utilization system based on solar radiation forecasting at one-day-ahead 24-hour thermal energy collection by using three different NN models. The proposed technique with application of NN is trained by weather data based on tree-based model, and tested according to forecast day. Since tree-based-model classifies a meteorological data exactly, NN will train a solar radiation with smoothly. The validity of the proposed technique is confirmed by computer simulations by use of actual meteorological data.展开更多
Two schemes（scheme Ⅰ and scheme Ⅱ）for designing a district cooling system（DCS）utilizing cold energy of liquefied natural gas（LNG）are presented.In scheme Ⅰ,LNG cold energy is used to produce ice,and then ice i...Two schemes（scheme Ⅰ and scheme Ⅱ）for designing a district cooling system（DCS）utilizing cold energy of liquefied natural gas（LNG）are presented.In scheme Ⅰ,LNG cold energy is used to produce ice,and then ice is transported to the central cooling plant of the DCS.In scheme Ⅱ,return water from the DCS is directly chilled by LNG cold energy,and the chilled water is then sent back to the central plant.The heat transportation loss is the main negative impact in the DCS and is emphatically analyzed when evaluating the efficiency of each scheme.The results show that the DCS utilizing LNG cold energy is feasible and valuable.The cooling supply distance of scheme Ⅱ is limited within 13 km while scheme Ⅰ has no distance limit.When the distance is between 6 and 13 km,scheme Ⅱ is more practical and effective.Contrarily,scheme Ⅰ has a better economic performance when the distance is shorter than 6 km or longer than 13 km.展开更多
This paper makes a study of some technical and engineering aspects by using C2 ＋ hydrocarbon separation facility at Guangdong Dapeng liquefied natural gas （GDLNG） terminal. In the C2＋ hydrocarbon extraction proces...This paper makes a study of some technical and engineering aspects by using C2 ＋ hydrocarbon separation facility at Guangdong Dapeng liquefied natural gas （GDLNG） terminal. In the C2＋ hydrocarbon extraction process, the cold energy contained in LNG will be utilized. In order to ensure the optimum operating conditions of the temlinal and C2 ＋ hydrocarbon extraction facility by optimizing the current operating processes of the terminal, the C2 ＋ hydrocarbon extraction facility construction plan is proposed. We conducted numerous calculations and simulations using such specific analysis software as PRO II 〈 version 7.0 〉. Additionally available flow data are used to verify the cyclic send-out rates from the terminal, thus establishing the current and future projected load factors. This study is intended to make sure that GDLNG can continue to supply gas via the pipeline system safely without interruptions and most significantly solves the effects of flow fluctuations at the terminal gasification send-out facility on the hydrocarbons extraction, ensuring optimum pipeline operations and ensuring safe and effective means for such C2＋ hydrocarbons extraction process as well. At the same time, the terminal is also in the optimum operation condition. This is very significant to the terminal safety operation and the energy conservation and emission reduction.展开更多
This paper took a 100,000 DWT LNG fuel powered ship as the research object.Based on the idea of"temperature matching,cascade utilization"and combined with the application conditions of the ship,a horizontal ...This paper took a 100,000 DWT LNG fuel powered ship as the research object.Based on the idea of"temperature matching,cascade utilization"and combined with the application conditions of the ship,a horizontal three-level nested Rankine cycle full-generation system which combined the high-temperature waste heat of the main engine flue gas with the low-temperature cold energy of LNG was proposed in this paper.Furthermore,based on the analysis and selection of the parameters which had high sensitivity to the system performance,the parameters of the proposed system were optimized by using the genetic algorithm.After optimization,the exergy efficiency of the marine LNG gasification cold energy cascade utilization power generation system can reach 48.06%,and the thermal efficiency can reach 35.56%.In addition,this paper took LNG net power generation as the performance index,and compared it with the typical LNG cold energy utilization power generation system in this field.The results showed that the unit mass flow LNG power generation of the system proposed in this paper was the largest,reaching 457.41 k W.展开更多
In this paper, the efficient utilization of liquefied natural gas(LNG) vaporization cold energy in offshore liquefied natural gas floating storage regasification unit(FSRU) is studied. On the basis of considering diff...In this paper, the efficient utilization of liquefied natural gas(LNG) vaporization cold energy in offshore liquefied natural gas floating storage regasification unit(FSRU) is studied. On the basis of considering different boil-off gas(BOG) practical treatment processes, a cascade comprehensive utilization scheme of cold energy of LNG based on the longitudinal three-stage organic Rankine cycle power generation and the low-grade cold energy used to frozen seawater desalination was proposed. Through the comparative analysis of the effects of the pure working fluid and eight mixed working fluids on the performance of the new system, the combination scheme of system mixed working fluid with the highest exergy efficiency of the system was determined. Then, the genetic algorithm was used to optimize the parameters of the new system. After optimization, the net output power of the LNG cold energy comprehensive utilization system proposed in this paper was 5186 kW, and the exergy efficiency is 30.6%. Considering the power generation and freshwater revenue, the annual economic benefit of the system operating is 18.71 million CNY.展开更多
基金the Science and Technology Foundation of Shaanxi Province (No.2002K08-G9).
文摘Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.
文摘In recent years, introduction of alternative energy sources such as solar energy is expected. Solar heat energy utilization systems are rapidly gaining acceptance as one of the best solutions to be an alternative energy source. However, thermal energy collection is influenced by solar radiation and weather conditions. In order to control a solar heat energy utilization system as accurate as possible, it requires method of solar radiation estimation. This paper proposes the forecast technique of a thermal energy collection of solar heat energy utilization system based on solar radiation forecasting at one-day-ahead 24-hour thermal energy collection by using three different NN models. The proposed technique with application of NN is trained by weather data based on tree-based model, and tested according to forecast day. Since tree-based-model classifies a meteorological data exactly, NN will train a solar radiation with smoothly. The validity of the proposed technique is confirmed by computer simulations by use of actual meteorological data.
文摘Two schemes（scheme Ⅰ and scheme Ⅱ）for designing a district cooling system（DCS）utilizing cold energy of liquefied natural gas（LNG）are presented.In scheme Ⅰ,LNG cold energy is used to produce ice,and then ice is transported to the central cooling plant of the DCS.In scheme Ⅱ,return water from the DCS is directly chilled by LNG cold energy,and the chilled water is then sent back to the central plant.The heat transportation loss is the main negative impact in the DCS and is emphatically analyzed when evaluating the efficiency of each scheme.The results show that the DCS utilizing LNG cold energy is feasible and valuable.The cooling supply distance of scheme Ⅱ is limited within 13 km while scheme Ⅰ has no distance limit.When the distance is between 6 and 13 km,scheme Ⅱ is more practical and effective.Contrarily,scheme Ⅰ has a better economic performance when the distance is shorter than 6 km or longer than 13 km.
文摘This paper makes a study of some technical and engineering aspects by using C2 ＋ hydrocarbon separation facility at Guangdong Dapeng liquefied natural gas （GDLNG） terminal. In the C2＋ hydrocarbon extraction process, the cold energy contained in LNG will be utilized. In order to ensure the optimum operating conditions of the temlinal and C2 ＋ hydrocarbon extraction facility by optimizing the current operating processes of the terminal, the C2 ＋ hydrocarbon extraction facility construction plan is proposed. We conducted numerous calculations and simulations using such specific analysis software as PRO II 〈 version 7.0 〉. Additionally available flow data are used to verify the cyclic send-out rates from the terminal, thus establishing the current and future projected load factors. This study is intended to make sure that GDLNG can continue to supply gas via the pipeline system safely without interruptions and most significantly solves the effects of flow fluctuations at the terminal gasification send-out facility on the hydrocarbons extraction, ensuring optimum pipeline operations and ensuring safe and effective means for such C2＋ hydrocarbons extraction process as well. At the same time, the terminal is also in the optimum operation condition. This is very significant to the terminal safety operation and the energy conservation and emission reduction.
文摘This paper took a 100,000 DWT LNG fuel powered ship as the research object.Based on the idea of"temperature matching,cascade utilization"and combined with the application conditions of the ship,a horizontal three-level nested Rankine cycle full-generation system which combined the high-temperature waste heat of the main engine flue gas with the low-temperature cold energy of LNG was proposed in this paper.Furthermore,based on the analysis and selection of the parameters which had high sensitivity to the system performance,the parameters of the proposed system were optimized by using the genetic algorithm.After optimization,the exergy efficiency of the marine LNG gasification cold energy cascade utilization power generation system can reach 48.06%,and the thermal efficiency can reach 35.56%.In addition,this paper took LNG net power generation as the performance index,and compared it with the typical LNG cold energy utilization power generation system in this field.The results showed that the unit mass flow LNG power generation of the system proposed in this paper was the largest,reaching 457.41 k W.
基金supported by special project of R&D and industrialization of Marine equipment of national development and reform commission of China(National Development and Reform Commission High Technology[2015]No.1409)。
文摘In this paper, the efficient utilization of liquefied natural gas(LNG) vaporization cold energy in offshore liquefied natural gas floating storage regasification unit(FSRU) is studied. On the basis of considering different boil-off gas(BOG) practical treatment processes, a cascade comprehensive utilization scheme of cold energy of LNG based on the longitudinal three-stage organic Rankine cycle power generation and the low-grade cold energy used to frozen seawater desalination was proposed. Through the comparative analysis of the effects of the pure working fluid and eight mixed working fluids on the performance of the new system, the combination scheme of system mixed working fluid with the highest exergy efficiency of the system was determined. Then, the genetic algorithm was used to optimize the parameters of the new system. After optimization, the net output power of the LNG cold energy comprehensive utilization system proposed in this paper was 5186 kW, and the exergy efficiency is 30.6%. Considering the power generation and freshwater revenue, the annual economic benefit of the system operating is 18.71 million CNY.
