Owing to the vulnerability of Invar to moisture in the membranes of LNG tanker cargo tank construction platforms(CTCPs),an energy-efficient ventilation system is needed to maintain a suitable thermal-moisture environm...Owing to the vulnerability of Invar to moisture in the membranes of LNG tanker cargo tank construction platforms(CTCPs),an energy-efficient ventilation system is needed to maintain a suitable thermal-moisture environment and a healthy workplace.However,the optimal distribution of supply and return devices that would guarantee worker satisfaction,air quality,and energy efficiency is unclear.Therefore,we conducted numerical simulations to determine the worker satisfaction indices(temperature,relative humidity,and carbon monoxide concentration satisfactions),air quality index(contaminant-removal efficiency),and energy efficiency index(heat-removal efficiency)with supply vane angles ranging from-75°to 0°and two return vent positions(the bottom return vent and the top return vent).The analytic hierarchy process(AHP)entropy weight method was employed to determine the optimal supply vane angle and return vent position for three design targets by considering these indices simultaneously.The results indicated that,with a supply angle of-45°and a bottom return vent,worker satisfaction and air quality were prioritized.Furthermore,a high energy performance of the ventilation system was achieved with a-15°supply angle and a bottom return vent.Moreover,a comprehensive graph of supply vane angles at both return heights,which could provide a reference for optimizing the ventilation system in LNG-CTCPs,is described.展开更多
As the largest inland river basin of China,the Tarim River Basin(TRB),known for its various natural resources and fragile environment,has an increased risk of ecological crisis due to the intensive exploitation and ut...As the largest inland river basin of China,the Tarim River Basin(TRB),known for its various natural resources and fragile environment,has an increased risk of ecological crisis due to the intensive exploitation and utilization of water and land resources.Since the Ecological Water Diversion Project(EWDP),which was implemented in 2001 to save endangered desert vegetation,there has been growing evidence of ecological improvement in local regions,but few studies have performed a comprehensive ecological vulnerability assessment of the whole TRB.This study established an evaluation framework integrating the analytic hierarchy process(AHP)and entropy method to estimate the ecological vulnerability of the TRB covering climatic,ecological,and socioeconomic indicators during 2000-2017.Based on the geographical detector model,the importance of ten driving factors on the spatial-temporal variations of ecological vulnerability was explored.The results showed that the ecosystem of the TRB was fragile,with more than half of the area(57.27%)dominated by very heavy and heavy grades of ecological vulnerability,and 28.40%of the area had potential and light grades of ecological vulnerability.The light grade of ecological vulnerability was distributed in the northern regions(Aksu River and Weigan River catchments)and western regions(Kashgar River and Yarkant River catchments),while the heavy grade was located in the southern regions(Kunlun Mountains and Qarqan River catchments)and the Mainstream catchment.The ecosystems in the western and northern regions were less vulnerable than those in the southern and eastern regions.From 2000 to 2017,the overall improvement in ecological vulnerability in the whole TRB showed that the areas with great ecological improvement increased by 46.11%,while the areas with ecological degradation decreased by 9.64%.The vegetation cover and potential evapotranspiration(PET)were the obvious driving factors,explaining 57.56% and 21.55%of the changes in ecological vulnerability across the TRB,respectively.In terms of ecological vulnerability grade changes,obvious spatial differences were observed in the upper,middle,and lower reaches of the TRB due to the different vegetation and hydrothermal conditions.The alpine source region of the TRB showed obvious ecological improvement due to increased precipitation and temperature,but the alpine meadow of the Kaidu River catchment in the Middle Tianshan Mountains experienced degradation associated with overgrazing and local drought.The improved agricultural management technologies had positive effects on farmland ecological improvement,while the desert vegetation in oasis-desert ecotones showed a decreasing trend as a result of cropland reclamation and intensive drought.The desert riparian vegetation in the lower reaches of the Tarim River was greatly improved due to the implementation of the EWDP,which has been active for tens of years.These results provide comprehensive knowledge about ecological processes and mechanisms in the whole TRB and help to develop environmental restoration measures based on different ecological vulnerability grades in each sub-catchment.展开更多
This study aims at determining the optimal CO2 separation technology for Chinese refineries, based on current available technologies, by the method of comprehensive evaluation. Firstly, according to the characteristic...This study aims at determining the optimal CO2 separation technology for Chinese refineries, based on current available technologies, by the method of comprehensive evaluation. Firstly, according to the characteristics of flue gas from Chinese refineries, three feasible CO2 separation technologies are selected. These are pressure swing adsorption （PSA）, chemical absorption （CA）, and membrane absorption （MA）. Secondly, an economic assessment of these three techniques is carried out in accordance with cash flow analysis. The results show that these three techniques all have economic feasibility and the PSA technique is the best. Finally, to further optimize the three techniques, a two-level fuzzy comprehensive evaluation model is established, including economic, technological, and environmental factors. Considering all the factors, PSA is optimal for Chinese refineries, followed by CA and MA. Therefore, to reduce Chinese refineries carbon emission, it is suggested that CO2 should be captured from off-gases using PSA.展开更多
基金This research described in this paper was supported by the Science and Technology Program of Jiangsu Province(No.BY2016073-10).
文摘Owing to the vulnerability of Invar to moisture in the membranes of LNG tanker cargo tank construction platforms(CTCPs),an energy-efficient ventilation system is needed to maintain a suitable thermal-moisture environment and a healthy workplace.However,the optimal distribution of supply and return devices that would guarantee worker satisfaction,air quality,and energy efficiency is unclear.Therefore,we conducted numerical simulations to determine the worker satisfaction indices(temperature,relative humidity,and carbon monoxide concentration satisfactions),air quality index(contaminant-removal efficiency),and energy efficiency index(heat-removal efficiency)with supply vane angles ranging from-75°to 0°and two return vent positions(the bottom return vent and the top return vent).The analytic hierarchy process(AHP)entropy weight method was employed to determine the optimal supply vane angle and return vent position for three design targets by considering these indices simultaneously.The results indicated that,with a supply angle of-45°and a bottom return vent,worker satisfaction and air quality were prioritized.Furthermore,a high energy performance of the ventilation system was achieved with a-15°supply angle and a bottom return vent.Moreover,a comprehensive graph of supply vane angles at both return heights,which could provide a reference for optimizing the ventilation system in LNG-CTCPs,is described.
基金This research was supported by the National Key Research and Development Plan of China(2017YFB0504204)the CAS Interdisciplinary Innovation Team(JCTD-2019-20)+1 种基金the Tianshan Innovation Team(2020D14016)the National Natural Science Foundation of China(U2003201).
文摘As the largest inland river basin of China,the Tarim River Basin(TRB),known for its various natural resources and fragile environment,has an increased risk of ecological crisis due to the intensive exploitation and utilization of water and land resources.Since the Ecological Water Diversion Project(EWDP),which was implemented in 2001 to save endangered desert vegetation,there has been growing evidence of ecological improvement in local regions,but few studies have performed a comprehensive ecological vulnerability assessment of the whole TRB.This study established an evaluation framework integrating the analytic hierarchy process(AHP)and entropy method to estimate the ecological vulnerability of the TRB covering climatic,ecological,and socioeconomic indicators during 2000-2017.Based on the geographical detector model,the importance of ten driving factors on the spatial-temporal variations of ecological vulnerability was explored.The results showed that the ecosystem of the TRB was fragile,with more than half of the area(57.27%)dominated by very heavy and heavy grades of ecological vulnerability,and 28.40%of the area had potential and light grades of ecological vulnerability.The light grade of ecological vulnerability was distributed in the northern regions(Aksu River and Weigan River catchments)and western regions(Kashgar River and Yarkant River catchments),while the heavy grade was located in the southern regions(Kunlun Mountains and Qarqan River catchments)and the Mainstream catchment.The ecosystems in the western and northern regions were less vulnerable than those in the southern and eastern regions.From 2000 to 2017,the overall improvement in ecological vulnerability in the whole TRB showed that the areas with great ecological improvement increased by 46.11%,while the areas with ecological degradation decreased by 9.64%.The vegetation cover and potential evapotranspiration(PET)were the obvious driving factors,explaining 57.56% and 21.55%of the changes in ecological vulnerability across the TRB,respectively.In terms of ecological vulnerability grade changes,obvious spatial differences were observed in the upper,middle,and lower reaches of the TRB due to the different vegetation and hydrothermal conditions.The alpine source region of the TRB showed obvious ecological improvement due to increased precipitation and temperature,but the alpine meadow of the Kaidu River catchment in the Middle Tianshan Mountains experienced degradation associated with overgrazing and local drought.The improved agricultural management technologies had positive effects on farmland ecological improvement,while the desert vegetation in oasis-desert ecotones showed a decreasing trend as a result of cropland reclamation and intensive drought.The desert riparian vegetation in the lower reaches of the Tarim River was greatly improved due to the implementation of the EWDP,which has been active for tens of years.These results provide comprehensive knowledge about ecological processes and mechanisms in the whole TRB and help to develop environmental restoration measures based on different ecological vulnerability grades in each sub-catchment.
基金the China University of Petroleum Foundationthe Research Institute of Safety and Environment TechnologyChina National Petroleum Corporation
文摘This study aims at determining the optimal CO2 separation technology for Chinese refineries, based on current available technologies, by the method of comprehensive evaluation. Firstly, according to the characteristics of flue gas from Chinese refineries, three feasible CO2 separation technologies are selected. These are pressure swing adsorption （PSA）, chemical absorption （CA）, and membrane absorption （MA）. Secondly, an economic assessment of these three techniques is carried out in accordance with cash flow analysis. The results show that these three techniques all have economic feasibility and the PSA technique is the best. Finally, to further optimize the three techniques, a two-level fuzzy comprehensive evaluation model is established, including economic, technological, and environmental factors. Considering all the factors, PSA is optimal for Chinese refineries, followed by CA and MA. Therefore, to reduce Chinese refineries carbon emission, it is suggested that CO2 should be captured from off-gases using PSA.
