Heat transfer and temperature evolution in overburden fracture and ground fissures are one of the essential topics for the identification of ground fissures via unmanned aerial vehicle(UAV) infrared imager. In this st...Heat transfer and temperature evolution in overburden fracture and ground fissures are one of the essential topics for the identification of ground fissures via unmanned aerial vehicle(UAV) infrared imager. In this study, discrete element software UDEC was employed to investigate the overburden fracture field under different mining conditions. Multiphysics software COMSOL were employed to investigate heat transfer and temperature evolution of overburden fracture and ground fissures under the influence of mining condition, fissure depth, fissure width, and month alternation. The UAV infrared field measurements also provided a calibration for numerical simulation. The results showed that for ground fissures connected to underground goaf(Fissure Ⅰ), the temperature difference increased with larger mining height and shallow buried depth. In addition, Fissure Ⅰ located in the boundary of the goaf have a greater temperature difference and is easier to be identified than fissures located above the mining goaf. For ground fissures having no connection to underground goaf(Fissure Ⅱ), the heat transfer is affected by the internal resistance of the overlying strata fracture when the depth of Fissure Ⅱ is greater than10 m, the temperature of Fissure Ⅱ gradually equals to the ground temperature as the fissures’ depth increases, and the fissures are difficult to be identified. The identification effect is most obvious for fissures larger than 16 cm under the same depth. In spring and summer, UAV infrared identification of mining fissures should be carried out during nighttime. This study provides the basis for the optimal time and season for the UAV infrared identification of different types of mining ground fissures.展开更多
In recent years,renewable energy has taken on an increasingly important role as a result of the depletion of traditional fossil fuels and the pressure of climate change.Due to the advantages of clean energy production...In recent years,renewable energy has taken on an increasingly important role as a result of the depletion of traditional fossil fuels and the pressure of climate change.Due to the advantages of clean energy production and wide availability,research on renewable energy has increased worldwide.We collected data from the Web of Science and the Derwent Innovations Index to analyze research trends in the field of renewable energy.It was found that the number of research achievements in this field has developed rapidly worldwide since 2005.The United States ranks first in the quantity and quality of literature and fourth in the number of authorized patents.China ranks second and first regarding the quantity of literature and authorized patents,respectively.Biomass energy,wind energy,and solar energy are trending research topics in various stages of development.China has maintained close cooperation with the United States,the United Kingdom,Australia,and other countries.展开更多
A trinomial tree model based on a real options approach was developed to evaluate the investment decisions on carbon capture,utilization,and storage(CCUS)retrofitted to the three main types of thermal power plants in ...A trinomial tree model based on a real options approach was developed to evaluate the investment decisions on carbon capture,utilization,and storage(CCUS)retrofitted to the three main types of thermal power plants in China under the same power generation and CO2 emissions levels.The plant types included pulverized coal(PC),integrated gasification combined cycle(IGCC),and natural gas combined cycle(NGCC)plants.We take into account a subsidy policy consistent with the 45Q tax credit of the U.S.,as well as uncertainty factors,such as carbon price,technological progress,CO_(2) geological storage paths,oil price,and electricity price.The results showed that the investment benefit of ordinary NGCC power plants is 93.04 million USD.This provides greater economic advantages than the other two plant types as their investment benefit is negative if the captured CO_(2) was used for enhanced water recovery(EWR),even if 45Q subsidies are provided.Compared with NGCC+CCUS power plants,PC+CCUS and IGCC+CCUS power plants have more advantages in terms of economic benefits and emission reduction.The 45Q subsidy policy reduced the critical carbon price,which determines the decision to invest or not,by 30.14 USDt^(-1) for the PC and IGCC power plants and by 15.24 USDt^(-1) for the NGCC power plants.Nevertheless,only when the subsidy reaches at least 71.84 USDt^(-1) and the period limit is canceled can all three types of power plants be motivated to invest in CCUS and used the capture CO_(2) for EWR.Overall,the government should focus on the application of CCUS in coal-fired power plants(in addition to developing gas power generation),especially when CO_(2) is used for enhanced oil recovery(EOR).The government could introduce fiscal policies,such as 45Q or stronger,to stimulate CCUS technology development in China.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52225402 and U1910206).
文摘Heat transfer and temperature evolution in overburden fracture and ground fissures are one of the essential topics for the identification of ground fissures via unmanned aerial vehicle(UAV) infrared imager. In this study, discrete element software UDEC was employed to investigate the overburden fracture field under different mining conditions. Multiphysics software COMSOL were employed to investigate heat transfer and temperature evolution of overburden fracture and ground fissures under the influence of mining condition, fissure depth, fissure width, and month alternation. The UAV infrared field measurements also provided a calibration for numerical simulation. The results showed that for ground fissures connected to underground goaf(Fissure Ⅰ), the temperature difference increased with larger mining height and shallow buried depth. In addition, Fissure Ⅰ located in the boundary of the goaf have a greater temperature difference and is easier to be identified than fissures located above the mining goaf. For ground fissures having no connection to underground goaf(Fissure Ⅱ), the heat transfer is affected by the internal resistance of the overlying strata fracture when the depth of Fissure Ⅱ is greater than10 m, the temperature of Fissure Ⅱ gradually equals to the ground temperature as the fissures’ depth increases, and the fissures are difficult to be identified. The identification effect is most obvious for fissures larger than 16 cm under the same depth. In spring and summer, UAV infrared identification of mining fissures should be carried out during nighttime. This study provides the basis for the optimal time and season for the UAV infrared identification of different types of mining ground fissures.
基金National Natural Science Foundation of China under Grant(no.71874193,71503249,71203008,71904014)the Asia-Pacific Network for Global Change Research(no.CBA2018-02MY-Fan)+1 种基金Young Elite Scientists Sponsorship Program by CAST(no.2016QNRC001),Beijing Excellent Talent Program(no.2015000020124G122)the Open Research Project of State Key Laboratory of Coal Resources and Safe Mining(China University of Mining and Technology)(no.SKLCRSM19KFA14).
文摘In recent years,renewable energy has taken on an increasingly important role as a result of the depletion of traditional fossil fuels and the pressure of climate change.Due to the advantages of clean energy production and wide availability,research on renewable energy has increased worldwide.We collected data from the Web of Science and the Derwent Innovations Index to analyze research trends in the field of renewable energy.It was found that the number of research achievements in this field has developed rapidly worldwide since 2005.The United States ranks first in the quantity and quality of literature and fourth in the number of authorized patents.China ranks second and first regarding the quantity of literature and authorized patents,respectively.Biomass energy,wind energy,and solar energy are trending research topics in various stages of development.China has maintained close cooperation with the United States,the United Kingdom,Australia,and other countries.
基金the financial support of National Natural Science Foundation of China(71874193,71503249,71203008,71904014)the Asia-Pacific Network for Global Change Research(CBA2018-02MY-Fan)+2 种基金Huo Yingdong Education Foundation(171072)the Fundamental Research Funds for the Central Universities(Nos.2020YJSNY01,2020SKNY01)the Open Research Project of State Key Laboratory of Coal Resources and Safe Mining(China University of Mining and Technology,SKLCRSM19KFA14).
文摘A trinomial tree model based on a real options approach was developed to evaluate the investment decisions on carbon capture,utilization,and storage(CCUS)retrofitted to the three main types of thermal power plants in China under the same power generation and CO2 emissions levels.The plant types included pulverized coal(PC),integrated gasification combined cycle(IGCC),and natural gas combined cycle(NGCC)plants.We take into account a subsidy policy consistent with the 45Q tax credit of the U.S.,as well as uncertainty factors,such as carbon price,technological progress,CO_(2) geological storage paths,oil price,and electricity price.The results showed that the investment benefit of ordinary NGCC power plants is 93.04 million USD.This provides greater economic advantages than the other two plant types as their investment benefit is negative if the captured CO_(2) was used for enhanced water recovery(EWR),even if 45Q subsidies are provided.Compared with NGCC+CCUS power plants,PC+CCUS and IGCC+CCUS power plants have more advantages in terms of economic benefits and emission reduction.The 45Q subsidy policy reduced the critical carbon price,which determines the decision to invest or not,by 30.14 USDt^(-1) for the PC and IGCC power plants and by 15.24 USDt^(-1) for the NGCC power plants.Nevertheless,only when the subsidy reaches at least 71.84 USDt^(-1) and the period limit is canceled can all three types of power plants be motivated to invest in CCUS and used the capture CO_(2) for EWR.Overall,the government should focus on the application of CCUS in coal-fired power plants(in addition to developing gas power generation),especially when CO_(2) is used for enhanced oil recovery(EOR).The government could introduce fiscal policies,such as 45Q or stronger,to stimulate CCUS technology development in China.
