This paper presents the thermodynamic performance analysis and comparison of four kinds of advanced pressurized fluidized bed combustion combined cycle (APFBC-CC) system schemes, two based on pressurized fluidized bed...This paper presents the thermodynamic performance analysis and comparison of four kinds of advanced pressurized fluidized bed combustion combined cycle (APFBC-CC) system schemes, two based on pressurized fluidized bed (PFB) combustion and the other two based on atmospheric circulating fluidized bed (CFB) combustion. The results show that the first scheme avoids high temperature gas filter, but has the lower cycle efficiency and syngas heating value. The second scheme can gain the highest cycle efficiency, however it is better to now lower the filter operating temperature. The third and fourth schemes, based on CFB, have lower efficiencies than the second one. But the fourth one, with preheating air/steam for gasification, can obtain the highest heating value of syngas and gain higher efficiency than the third one.展开更多
Thermally regenerative electrochemical cycle(TREC)is a novel and effective heat-to-electricity technology for harvesting low-grade heat.Currently,reported TREC analyses have been based on the Stirling cycle of ideal i...Thermally regenerative electrochemical cycle(TREC)is a novel and effective heat-to-electricity technology for harvesting low-grade heat.Currently,reported TREC analyses have been based on the Stirling cycle of ideal infinite heat source and infinite time for heat transfer.However,this will lead to inaccuracy when the scenario deviates from the ideal case.In this study,a systematic thermodynamic analysis on TREC is performed to address this problem.Based on different heat transfer situations,the description of thermodynamic processes and the corresponding mathematical models are established.At the same time,the TREC system,with the solar collector as the high-temperature heat source and the environment as the low-temperature heat source,is employed as a case.And the study delved into discrepancies arising from incongruences between the practical operational process and the traditional ideal analytical methodologies,along with an investigation of the different thermal environment impact on system performance.The findings suggest that the finite analysis method should be used when the actual operating time of the system is shorter than the desired equilibrium period.On the contrary,the use of the infinite analysis method,in this case,produces an error,the magnitude of which is directly related to the operating time,whereas when the time reaches 80%of the equilibrium time the error can be controlled to less than 2%.The influence of the heat source on the operating phase of the system is mainly in the temperature equilibrium and the rate of temperature equilibrium.This effect is proportional to the thermal capacitance and is also positively related to the system performance.Therefore,to improve system performance,it is recommended that a high-temperature heat source with a high ratio of thermal capacitance to system thermal capacitance should be selected and that the response time should slightly exceed the system equilibrium duration.展开更多
A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the ...A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.展开更多
A resourceability on nuclear fuel cycle by transmutation of fission products in the spent fuel of nuclear reactors is discussed in this paper to investigate the feasibility of ＂creation and utilization＂ of Apr6s ORI...A resourceability on nuclear fuel cycle by transmutation of fission products in the spent fuel of nuclear reactors is discussed in this paper to investigate the feasibility of ＂creation and utilization＂ of Apr6s ORIENT from Adv.-ORIENT cycle, in which chemical ＂separation and utilization＂ of nuclear rare metals （platinum group metals, Mo, Tc, rare earth, etc.） has been proposed since FY2006. Apr6s ORIENT research program was newly initiated in FY2011 for nuclear transmutation of fission products into stable or short-lived highly-valuable elements. In the resourceability of rare earth metals from fission products, non-radioactive Nd and Dy can be created from Pr and Tb, respectively, by transmutation. Especially, the Dy creation has relatively high feasibility of about 10-20 %/y in creation rate. A proper moderation of neutrons in blanket of fast reactors may be required to provide a high creation rate of La from Ba. In light platinum group metals, non-radioactive Ru can be created from Tc by transmutation, of which creation rate is about 4-5 %/y in blanket of fast reactors. Pd created from Rh is almost non-radioactively depending on the isotope fraction of 107pd. Rh creation from Ru is not feasible under the neutron irradiation of typical nuclear reactors.展开更多
文摘This paper presents the thermodynamic performance analysis and comparison of four kinds of advanced pressurized fluidized bed combustion combined cycle (APFBC-CC) system schemes, two based on pressurized fluidized bed (PFB) combustion and the other two based on atmospheric circulating fluidized bed (CFB) combustion. The results show that the first scheme avoids high temperature gas filter, but has the lower cycle efficiency and syngas heating value. The second scheme can gain the highest cycle efficiency, however it is better to now lower the filter operating temperature. The third and fourth schemes, based on CFB, have lower efficiencies than the second one. But the fourth one, with preheating air/steam for gasification, can obtain the highest heating value of syngas and gain higher efficiency than the third one.
基金the financial support received from the National Nature Science Foundation of China(NSFC)project(Grant 52276216)the Anhui Provincial Nature Science Foundation project(Grant 2108085UD03)。
文摘Thermally regenerative electrochemical cycle(TREC)is a novel and effective heat-to-electricity technology for harvesting low-grade heat.Currently,reported TREC analyses have been based on the Stirling cycle of ideal infinite heat source and infinite time for heat transfer.However,this will lead to inaccuracy when the scenario deviates from the ideal case.In this study,a systematic thermodynamic analysis on TREC is performed to address this problem.Based on different heat transfer situations,the description of thermodynamic processes and the corresponding mathematical models are established.At the same time,the TREC system,with the solar collector as the high-temperature heat source and the environment as the low-temperature heat source,is employed as a case.And the study delved into discrepancies arising from incongruences between the practical operational process and the traditional ideal analytical methodologies,along with an investigation of the different thermal environment impact on system performance.The findings suggest that the finite analysis method should be used when the actual operating time of the system is shorter than the desired equilibrium period.On the contrary,the use of the infinite analysis method,in this case,produces an error,the magnitude of which is directly related to the operating time,whereas when the time reaches 80%of the equilibrium time the error can be controlled to less than 2%.The influence of the heat source on the operating phase of the system is mainly in the temperature equilibrium and the rate of temperature equilibrium.This effect is proportional to the thermal capacitance and is also positively related to the system performance.Therefore,to improve system performance,it is recommended that a high-temperature heat source with a high ratio of thermal capacitance to system thermal capacitance should be selected and that the response time should slightly exceed the system equilibrium duration.
基金supported by the State Key Laboratory of Coal Resources and Sate Mining,China University of Mining and Technology (No.SKLCRSM13X07)the National Natural Science Foundation of China (No.51174195)+1 种基金Chinese National Programs for Fundamental Research and Development (No.2013CB227900)the Fundamental Research Funds for the Central Universities (No.2014XT01)
文摘A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.
文摘A resourceability on nuclear fuel cycle by transmutation of fission products in the spent fuel of nuclear reactors is discussed in this paper to investigate the feasibility of ＂creation and utilization＂ of Apr6s ORIENT from Adv.-ORIENT cycle, in which chemical ＂separation and utilization＂ of nuclear rare metals （platinum group metals, Mo, Tc, rare earth, etc.） has been proposed since FY2006. Apr6s ORIENT research program was newly initiated in FY2011 for nuclear transmutation of fission products into stable or short-lived highly-valuable elements. In the resourceability of rare earth metals from fission products, non-radioactive Nd and Dy can be created from Pr and Tb, respectively, by transmutation. Especially, the Dy creation has relatively high feasibility of about 10-20 %/y in creation rate. A proper moderation of neutrons in blanket of fast reactors may be required to provide a high creation rate of La from Ba. In light platinum group metals, non-radioactive Ru can be created from Tc by transmutation, of which creation rate is about 4-5 %/y in blanket of fast reactors. Pd created from Rh is almost non-radioactively depending on the isotope fraction of 107pd. Rh creation from Ru is not feasible under the neutron irradiation of typical nuclear reactors.
