Under the Paris agreement, China has committed to reducing CO_2 emissions by 60%–65% per unit of GDP by 2030.Since CO_2 emissions from coal-fired power plants currently account for over 30% of the total carbon emissi...Under the Paris agreement, China has committed to reducing CO_2 emissions by 60%–65% per unit of GDP by 2030.Since CO_2 emissions from coal-fired power plants currently account for over 30% of the total carbon emissions in China, it will be necessary to mitigate at least some of these emissions to achieve this goal. Studies by the International Energy Agency(IEA) indicate CCS technology has the potential to contribute 14% of global emission reductions, followed by 40% of higher energy efficiency and 35% of renewable energy, which is considered as the most promising technology to significantly reduce carbon emissions for current coal-fired power plants.Moreover, the announcement of a Chinese national carbon trading market in late 2017 signals an opportunity for the commercial deployment of CO_2 capture technologies.Currently, the only commercially demonstrated technology for post-combustion CO_2 capture technology from power plants is solvent-based absorption. While commercially viable, the costs of deploying this technology are high. This has motivated efforts to develop more affordable alternatives, including advanced solvents, membranes,and sorbent capture systems. Of these approaches, advanced solvents have received the most attention in terms of research and demonstration. In contrast, sorbent capture technology has less attention, despite its potential for much lower energy consumption due to the absence of water in the sorbent. This paper reviews recent progress in the development of sorbent materials modified by amine functionalities with an emphasis on material characterization methods and the effects of operating conditions on performance. The main problems and challenges that need to be overcome to improve the competitiveness of sorbent-based capture technologies are discussed.展开更多
Lithium metal has a high theoretical capacity of 3860 mAh g^-1 and a low electrochemical potential(-3.04 V vs.H2/H^+).Hence,using a lithium anode significantly improves the energy density of a secondary battery.Howeve...Lithium metal has a high theoretical capacity of 3860 mAh g^-1 and a low electrochemical potential(-3.04 V vs.H2/H^+).Hence,using a lithium anode significantly improves the energy density of a secondary battery.However,the lithium dendrites generated on the lithium anode during the platingdissolution process significantly reduce its cycling life and safety.Here,we provide a simple method for lithium anode protection,by applying a free-standing porous carbon film with a high specific surface area to reduce the local current density and obtain a homogenous ion distribution.The protected lithium anode has a long cycle life over 1000 h when cycled at 3 mA cm^-2 with a lithium capacity of 2.5 mAh cm^-2.Moreover,the deposited lithium has a smoother surface than Li anode without carbon protection.This study will promote the wide application of Li-metal-based batteries with high safety levels.展开更多
Abstract Here,we provide a status update of an integrated gasification fuel cell(IGFC)power-generation system being developed at the National Institute of Clean-and-Low-Carbon in China at the megawatt thermal(MWth)sca...Abstract Here,we provide a status update of an integrated gasification fuel cell(IGFC)power-generation system being developed at the National Institute of Clean-and-Low-Carbon in China at the megawatt thermal(MWth)scale.This system is designed to use coal as fuel to produce syngas as a first step,similar to that employed for the integrated gasification combined cycle.Subsequently,the solid-oxide fuel-cell(SOFC)system is used to convert chemical energy to electricity directly through an electrochemical reaction without combustion.This system leads to higher efficiency as compared with that from a traditional coal-fired power plant.The unreacted fuel in the SOFC system is transported to an oxygencombustor to be converted to steam and carbon dioxide(CO_(2)).Through a heat-recovery system,the steam is condensed and removed,and CO_(2) is enriched and captured for sequestration or utilization.Comprehensive economic analyses for a typical IGFC system was performed and the results were compared with those for a supercritical pulverized coal-fired power plant.The SOFC stacks selected for IGFC development were tested and qualified under hydrogen and simulated coal syngas fuel.Experimental results using SOFC stacks and thermodynamic analyses indicated that the control of hydrogen/CO ratio of syngas and steam/CO ratio is important to avoid carbon deposition with the fuel pipe.A 20-kW SOFC unit is under development with design power output of 20 kW and DC efficiency of 50.41%.A 100 kW-level subsystem will consist of 6920-kW power-generation units,and the MWth IGFC system will consist of 59100 kWlevel subsystems.展开更多
Given the dominant share of coal in China’s energy-generation mix and the fact that>50% of the power plants in the country are currently<15 years old,efforts to significantly reduce China’s CO_(2) footprint wi...Given the dominant share of coal in China’s energy-generation mix and the fact that>50% of the power plants in the country are currently<15 years old,efforts to significantly reduce China’s CO_(2) footprint will require the deployment of CO_(2) capture across at least part of its fleet of coal-fired power plants.CO_(2)-capture technology is reaching commercial maturity,but it is still necessary to adapt the technology to regional conditions,such as power-plant design and flexible operation in the China context.Slipstream facilities provide valuable field data to support the commercialization of CO_(2) capture.We have built a slipstream facility at Jiangyou power plant in Sichuan that will allow us to explore China-relevant issues,especially flexible operation,over the next few years.We plan to share our results with the broader CO_(2)-capture and CO_(2)-storage(CCS)community to accelerate the deployment of CCS in China.This paper describes the design of the slipstream facility and presents results from our steady-state qualification tests using a well-studied benchmark solvent:30% wt monoethanolamine(MEA).The results from our MEA tests compare favorably to results reported from other slipstream-test facilities around the world,allowing us to commission our system and establish a reference baseline for future studies.展开更多
CO_(2)capture,utilization and storage(CCUS)is recognized as a uniquely important option in global efforts to control anthropogenic greenhouse-gas(GHG)emissions.Despite significant progress globally in advancing the ma...CO_(2)capture,utilization and storage(CCUS)is recognized as a uniquely important option in global efforts to control anthropogenic greenhouse-gas(GHG)emissions.Despite significant progress globally in advancing the maturity of the various component technologies and their assembly into full-chain demonstrations,a gap remains on the path to widespread deployment in many countries.In this paper,we focus on the importance of business models adapted to the unique technical features and sociopolitical drivers in different regions as a necessary component of commercial scale-up and how lessons might be shared across borders.We identify three archetypes for CCUS development-resource recovery,green growth and low-carbon grids-each with different near-term issues that,if addressed,will enhance the prospect of successful commercial deployment.These archetypes provide a framing mechanism that can help to translate experience in one region or context to other locations by clarifying the most important technical issues and policy requirements.Going forward,the archetype framework also provides guidance on how different regions can converge on the most effective use of CCUS as part of global deep-decarbonization efforts over the long term.展开更多
Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims....Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims.We illustrate the point using examples from public transit.Although the fuelling energy requirements of public fleets represent a small fraction of the eventual total demand across the transportation sector,the predictable and long-term nature of the refuelling profiles can reduce the financing risk.With appropriate coordination across the energy supply chain,near-term investments can be used to support scale-up of wider efforts to decarbonize the transportation sector and electric grid.We present two examples from California-one related to overnight power for battery electric bus charging and the other related to medium-scale supply chains for zero-carbon hydrogen production-to illustrate how this might be achieved.展开更多
The cost of delivered H2 using the liquid-distribution pathway will approach$4.3-8.0/kg in the USA and 26-52 RMB/kg in China by around 2030,assuming large-scale adoption.Historically,hydrogen as an industrial gas and ...The cost of delivered H2 using the liquid-distribution pathway will approach$4.3-8.0/kg in the USA and 26-52 RMB/kg in China by around 2030,assuming large-scale adoption.Historically,hydrogen as an industrial gas and a chemical feedstock has enjoyed a long and successful history.However,it has been slow to take off as an energy carrier for transportation,despite its benefits in energy diversity,security and environmental stewardship.A key reason for this lack of progress is that the cost is currently too high to displace petroleum-based fuels.This paper reviews the prospects for hydrogen as an energy carrier for transportation,clarifies the current drivers for cost in the USA and China,and shows the potential for a liquid-hydrogen supply chain to reduce the costs of delivered H2.Technical and economic trade-offs between individual steps in the supply chain(viz.production,transportation,refuelling)are examined and used to show that liquid-H2(LH2)distribution approaches offer a path to reducing the delivery cost of H2 to the point at which it could be competitive with gasoline and diesel fuel.展开更多
Membrane-based separation technologies have the potential to lower the cost of post-combustion CO_(2) capture from power-plant flue gases through reduced energy and capital costs relative to conventional solvent appro...Membrane-based separation technologies have the potential to lower the cost of post-combustion CO_(2) capture from power-plant flue gases through reduced energy and capital costs relative to conventional solvent approaches.Studies have shown promise under controlled conditions,but there is a need for data on performance and reliability under field conditions.Coal-fired power plants in China operate in a dynamic manner,with increases and decreases in output causing changes in flue-gas composition.In this paper,we describe the first field test of a membrane-based post-combustion CO_(2)-capture system connected to a dynamically operating power plant in China.We report the performance of a Membrane Technology Research,Inc.(MTR)Polaris^(TM) membrane-based capture system over a range of plant operating loads ranging from 54%to 84%and conducted an operational stability test over a 168-h period during which the power plant was operating at an average load of 55%,but ramped as high as 79%and as low as 55%.Our results confirm the ability of a membrane capture system to operate effectively over a wide range of host-plant operating conditions,but also identity several issues related to plant integration,system control and resilience in the face of host-plant upsets that require attention as membrane separation systems move towards commercial use.展开更多
基金Supported by the National Key Research and Development Program of China(2017YFB0603301)
文摘Under the Paris agreement, China has committed to reducing CO_2 emissions by 60%–65% per unit of GDP by 2030.Since CO_2 emissions from coal-fired power plants currently account for over 30% of the total carbon emissions in China, it will be necessary to mitigate at least some of these emissions to achieve this goal. Studies by the International Energy Agency(IEA) indicate CCS technology has the potential to contribute 14% of global emission reductions, followed by 40% of higher energy efficiency and 35% of renewable energy, which is considered as the most promising technology to significantly reduce carbon emissions for current coal-fired power plants.Moreover, the announcement of a Chinese national carbon trading market in late 2017 signals an opportunity for the commercial deployment of CO_2 capture technologies.Currently, the only commercially demonstrated technology for post-combustion CO_2 capture technology from power plants is solvent-based absorption. While commercially viable, the costs of deploying this technology are high. This has motivated efforts to develop more affordable alternatives, including advanced solvents, membranes,and sorbent capture systems. Of these approaches, advanced solvents have received the most attention in terms of research and demonstration. In contrast, sorbent capture technology has less attention, despite its potential for much lower energy consumption due to the absence of water in the sorbent. This paper reviews recent progress in the development of sorbent materials modified by amine functionalities with an emphasis on material characterization methods and the effects of operating conditions on performance. The main problems and challenges that need to be overcome to improve the competitiveness of sorbent-based capture technologies are discussed.
文摘Lithium metal has a high theoretical capacity of 3860 mAh g^-1 and a low electrochemical potential(-3.04 V vs.H2/H^+).Hence,using a lithium anode significantly improves the energy density of a secondary battery.However,the lithium dendrites generated on the lithium anode during the platingdissolution process significantly reduce its cycling life and safety.Here,we provide a simple method for lithium anode protection,by applying a free-standing porous carbon film with a high specific surface area to reduce the local current density and obtain a homogenous ion distribution.The protected lithium anode has a long cycle life over 1000 h when cycled at 3 mA cm^-2 with a lithium capacity of 2.5 mAh cm^-2.Moreover,the deposited lithium has a smoother surface than Li anode without carbon protection.This study will promote the wide application of Li-metal-based batteries with high safety levels.
基金The authors thank the Ministry of Science and Technology of the People’s Republic of China for financial support under contract of 2017YEB061900。
文摘Abstract Here,we provide a status update of an integrated gasification fuel cell(IGFC)power-generation system being developed at the National Institute of Clean-and-Low-Carbon in China at the megawatt thermal(MWth)scale.This system is designed to use coal as fuel to produce syngas as a first step,similar to that employed for the integrated gasification combined cycle.Subsequently,the solid-oxide fuel-cell(SOFC)system is used to convert chemical energy to electricity directly through an electrochemical reaction without combustion.This system leads to higher efficiency as compared with that from a traditional coal-fired power plant.The unreacted fuel in the SOFC system is transported to an oxygencombustor to be converted to steam and carbon dioxide(CO_(2)).Through a heat-recovery system,the steam is condensed and removed,and CO_(2) is enriched and captured for sequestration or utilization.Comprehensive economic analyses for a typical IGFC system was performed and the results were compared with those for a supercritical pulverized coal-fired power plant.The SOFC stacks selected for IGFC development were tested and qualified under hydrogen and simulated coal syngas fuel.Experimental results using SOFC stacks and thermodynamic analyses indicated that the control of hydrogen/CO ratio of syngas and steam/CO ratio is important to avoid carbon deposition with the fuel pipe.A 20-kW SOFC unit is under development with design power output of 20 kW and DC efficiency of 50.41%.A 100 kW-level subsystem will consist of 6920-kW power-generation units,and the MWth IGFC system will consist of 59100 kWlevel subsystems.
文摘Given the dominant share of coal in China’s energy-generation mix and the fact that>50% of the power plants in the country are currently<15 years old,efforts to significantly reduce China’s CO_(2) footprint will require the deployment of CO_(2) capture across at least part of its fleet of coal-fired power plants.CO_(2)-capture technology is reaching commercial maturity,but it is still necessary to adapt the technology to regional conditions,such as power-plant design and flexible operation in the China context.Slipstream facilities provide valuable field data to support the commercialization of CO_(2) capture.We have built a slipstream facility at Jiangyou power plant in Sichuan that will allow us to explore China-relevant issues,especially flexible operation,over the next few years.We plan to share our results with the broader CO_(2)-capture and CO_(2)-storage(CCS)community to accelerate the deployment of CCS in China.This paper describes the design of the slipstream facility and presents results from our steady-state qualification tests using a well-studied benchmark solvent:30% wt monoethanolamine(MEA).The results from our MEA tests compare favorably to results reported from other slipstream-test facilities around the world,allowing us to commission our system and establish a reference baseline for future studies.
文摘CO_(2)capture,utilization and storage(CCUS)is recognized as a uniquely important option in global efforts to control anthropogenic greenhouse-gas(GHG)emissions.Despite significant progress globally in advancing the maturity of the various component technologies and their assembly into full-chain demonstrations,a gap remains on the path to widespread deployment in many countries.In this paper,we focus on the importance of business models adapted to the unique technical features and sociopolitical drivers in different regions as a necessary component of commercial scale-up and how lessons might be shared across borders.We identify three archetypes for CCUS development-resource recovery,green growth and low-carbon grids-each with different near-term issues that,if addressed,will enhance the prospect of successful commercial deployment.These archetypes provide a framing mechanism that can help to translate experience in one region or context to other locations by clarifying the most important technical issues and policy requirements.Going forward,the archetype framework also provides guidance on how different regions can converge on the most effective use of CCUS as part of global deep-decarbonization efforts over the long term.
文摘Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims.We illustrate the point using examples from public transit.Although the fuelling energy requirements of public fleets represent a small fraction of the eventual total demand across the transportation sector,the predictable and long-term nature of the refuelling profiles can reduce the financing risk.With appropriate coordination across the energy supply chain,near-term investments can be used to support scale-up of wider efforts to decarbonize the transportation sector and electric grid.We present two examples from California-one related to overnight power for battery electric bus charging and the other related to medium-scale supply chains for zero-carbon hydrogen production-to illustrate how this might be achieved.
文摘The cost of delivered H2 using the liquid-distribution pathway will approach$4.3-8.0/kg in the USA and 26-52 RMB/kg in China by around 2030,assuming large-scale adoption.Historically,hydrogen as an industrial gas and a chemical feedstock has enjoyed a long and successful history.However,it has been slow to take off as an energy carrier for transportation,despite its benefits in energy diversity,security and environmental stewardship.A key reason for this lack of progress is that the cost is currently too high to displace petroleum-based fuels.This paper reviews the prospects for hydrogen as an energy carrier for transportation,clarifies the current drivers for cost in the USA and China,and shows the potential for a liquid-hydrogen supply chain to reduce the costs of delivered H2.Technical and economic trade-offs between individual steps in the supply chain(viz.production,transportation,refuelling)are examined and used to show that liquid-H2(LH2)distribution approaches offer a path to reducing the delivery cost of H2 to the point at which it could be competitive with gasoline and diesel fuel.
基金This work is financially supported by the National Key R&D Program of China(2017YFB0603301).
文摘Membrane-based separation technologies have the potential to lower the cost of post-combustion CO_(2) capture from power-plant flue gases through reduced energy and capital costs relative to conventional solvent approaches.Studies have shown promise under controlled conditions,but there is a need for data on performance and reliability under field conditions.Coal-fired power plants in China operate in a dynamic manner,with increases and decreases in output causing changes in flue-gas composition.In this paper,we describe the first field test of a membrane-based post-combustion CO_(2)-capture system connected to a dynamically operating power plant in China.We report the performance of a Membrane Technology Research,Inc.(MTR)Polaris^(TM) membrane-based capture system over a range of plant operating loads ranging from 54%to 84%and conducted an operational stability test over a 168-h period during which the power plant was operating at an average load of 55%,but ramped as high as 79%and as low as 55%.Our results confirm the ability of a membrane capture system to operate effectively over a wide range of host-plant operating conditions,but also identity several issues related to plant integration,system control and resilience in the face of host-plant upsets that require attention as membrane separation systems move towards commercial use.
