Chemical-looping gasification （CLG） is a novel process for syngas generation from solid fuels, sharing the same basic principles as chemical-looping combustion （CLC）. It also uses oxygen carriers （mainly metal ox...Chemical-looping gasification （CLG） is a novel process for syngas generation from solid fuels, sharing the same basic principles as chemical-looping combustion （CLC）. It also uses oxygen carriers （mainly metal oxide and calcium sulfate） to transfer heat and oxygen to the fuel. In this paper, the primary investigation into the CLG process with CaSO4 as oxygen carrier was carried out by thermodynamic analysis and experiments in the tube reactor. Sulfur-contained gas emission was mainly H2S rather than SO2 in the CLG process, showing some different features from the CLC. The mass and heat balance of CLG processes were calculated thermodynamically to determinate the auto-thermal operating conditions with different CaSO4/C and steam/C molar ratios. It was found that the CaSO4/C molar ratio should be higher than 0.2 to reach auto-thermal balance. The effect of temperature on the reactions between oxygen carrier and coal was investigated based on Gibbs free energy minimum method and ex- perimental results. It indicated that high temperature favored the CLG process in the fuel reactor and part of syngas was consumed to compensate for auto-thermal system.展开更多
The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs )over the last two decades are reviewed. The criteria for the application of materials as interconnects ar...The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs )over the last two decades are reviewed. The criteria for the application of materials as interconnects are highlighted. Interconnects based on lanthanum chromite ceramics demonstrate many inherent drawbacks and therefore are only useful for SOFCs operating around 1000℃. The advance in the research of anode-supported flat SOFCs facilitates the replacement of ceramic interconnects with metallic ones due to their significantly lowered working temperature. Besides, interconnects made of metals or alloys offer many advantages as compared to their ceramic counterpart. The oxidation response and thermal expansion behaviors of various prospective metallic interconnects are examined and evaluated. The minimization of contact resistance to achieve desired and reliable stack performance during their projected lifetime still remains a highly challenging issue with metallic interconnects. Inexpensive coating materials and techniques may play a key role in promoting the commercialization of SOFC stack whose interconnects are constructed of some current commercially available alloys. Alternatively, development of new metallic materials that are capable of forming stable oxide scales with sluggish growth rate and sufficient electrical conductivity is called for.展开更多
Bionics （the imitation or abstraction of the ＂inventions＂ of nature） and, to an even greater extent, syn- thetic biology, will be as relevant to engineering development and industry as the silicon chip was over th...Bionics （the imitation or abstraction of the ＂inventions＂ of nature） and, to an even greater extent, syn- thetic biology, will be as relevant to engineering development and industry as the silicon chip was over the last 50 years. Chemical industries already use so-called ＂white biotechnology＂ for new processes, new raw materials, and more sustainable use of resources. Synthetic biology is also used for the devel- opment of second-generation biofuels and for harvesting the sun＇s energy with the help of tailor-made microorganisms or biometrically designed catalysts. The market potential for bionics in medicine, en- gineering processes, and DNA storage is huge. ＂Moonshot＂ projects are already aggressively focusing on diseases and new materials, and a US-led competition is currently underway with the aim of creating a thousand new molecules. This article describes a timeline that starts with current projects and then moves on to code engineering projects and their implications, artificial DNA, signaling molecules, and biological circuitry. Beyond these projects, one of the next frontiers in bionics is the design of synthetic metabolisms that include artificial food chains and foods, and the bioengineering of raw materials; all of which will lead to new insights into biological principles. Bioengineering will be an innovation motor just as digitalization is today. This article discusses pertinent examples of bioengineering, particularly the use of alternative carbon-based biofuels and the techniques and perils of cell modification. Big data, analytics, and massive storage are important factors in this next frontier. Although synthetic biology will be as pervasive and transformative in the next 50 years as digitization and the Intemet are today, its ap- plications and impacts are still in nascent stages. This article provides a general taxonomy in which the development of bioengineering is classified in five stages （DNA analysis, bio-circuits, minimal genomes, protocells, xenobiology） from the familiar to the unknown, with implications for safety and security, in- dustrial development, and the development of bioengineering and biotechnology as an interdisciplinary field. Ethical issues and the importance of a public debate about the consequences of bionics and syn- thetic biology are discussed.展开更多
In this study, a coal gasification model is developed based on nine simultaneous reactions. For given gasification temperature and pressure, the air/fuel and water vapor/fuel ratio are optimized for maximum H2/CO rati...In this study, a coal gasification model is developed based on nine simultaneous reactions. For given gasification temperature and pressure, the air/fuel and water vapor/fuel ratio are optimized for maximum H2/CO ratio by parametric study. Furthermore, the cold gas efficiency and higher heating value of the synthesis gas produced are computed for each case. Optimum locations of investigated parameters are also searched for maximizing cold gas efficiency and higher heating value of the synthesis gas.展开更多
基金Supported by the National~ Natural Science Foundation of China （20876079）, the Natural Science Funds for Distinguished Young Scholar in Shandong Province （JQ200904）, and Shandong Province Key Technologies Research and Development Program of China （2008GG 10006010, 2009GG 10007001）.
文摘Chemical-looping gasification （CLG） is a novel process for syngas generation from solid fuels, sharing the same basic principles as chemical-looping combustion （CLC）. It also uses oxygen carriers （mainly metal oxide and calcium sulfate） to transfer heat and oxygen to the fuel. In this paper, the primary investigation into the CLG process with CaSO4 as oxygen carrier was carried out by thermodynamic analysis and experiments in the tube reactor. Sulfur-contained gas emission was mainly H2S rather than SO2 in the CLG process, showing some different features from the CLC. The mass and heat balance of CLG processes were calculated thermodynamically to determinate the auto-thermal operating conditions with different CaSO4/C and steam/C molar ratios. It was found that the CaSO4/C molar ratio should be higher than 0.2 to reach auto-thermal balance. The effect of temperature on the reactions between oxygen carrier and coal was investigated based on Gibbs free energy minimum method and ex- perimental results. It indicated that high temperature favored the CLG process in the fuel reactor and part of syngas was consumed to compensate for auto-thermal system.
文摘The various stages and progress in the development of interconnect materials for solid oxide fuel cells (SOFCs )over the last two decades are reviewed. The criteria for the application of materials as interconnects are highlighted. Interconnects based on lanthanum chromite ceramics demonstrate many inherent drawbacks and therefore are only useful for SOFCs operating around 1000℃. The advance in the research of anode-supported flat SOFCs facilitates the replacement of ceramic interconnects with metallic ones due to their significantly lowered working temperature. Besides, interconnects made of metals or alloys offer many advantages as compared to their ceramic counterpart. The oxidation response and thermal expansion behaviors of various prospective metallic interconnects are examined and evaluated. The minimization of contact resistance to achieve desired and reliable stack performance during their projected lifetime still remains a highly challenging issue with metallic interconnects. Inexpensive coating materials and techniques may play a key role in promoting the commercialization of SOFC stack whose interconnects are constructed of some current commercially available alloys. Alternatively, development of new metallic materials that are capable of forming stable oxide scales with sluggish growth rate and sufficient electrical conductivity is called for.
文摘Bionics （the imitation or abstraction of the ＂inventions＂ of nature） and, to an even greater extent, syn- thetic biology, will be as relevant to engineering development and industry as the silicon chip was over the last 50 years. Chemical industries already use so-called ＂white biotechnology＂ for new processes, new raw materials, and more sustainable use of resources. Synthetic biology is also used for the devel- opment of second-generation biofuels and for harvesting the sun＇s energy with the help of tailor-made microorganisms or biometrically designed catalysts. The market potential for bionics in medicine, en- gineering processes, and DNA storage is huge. ＂Moonshot＂ projects are already aggressively focusing on diseases and new materials, and a US-led competition is currently underway with the aim of creating a thousand new molecules. This article describes a timeline that starts with current projects and then moves on to code engineering projects and their implications, artificial DNA, signaling molecules, and biological circuitry. Beyond these projects, one of the next frontiers in bionics is the design of synthetic metabolisms that include artificial food chains and foods, and the bioengineering of raw materials; all of which will lead to new insights into biological principles. Bioengineering will be an innovation motor just as digitalization is today. This article discusses pertinent examples of bioengineering, particularly the use of alternative carbon-based biofuels and the techniques and perils of cell modification. Big data, analytics, and massive storage are important factors in this next frontier. Although synthetic biology will be as pervasive and transformative in the next 50 years as digitization and the Intemet are today, its ap- plications and impacts are still in nascent stages. This article provides a general taxonomy in which the development of bioengineering is classified in five stages （DNA analysis, bio-circuits, minimal genomes, protocells, xenobiology） from the familiar to the unknown, with implications for safety and security, in- dustrial development, and the development of bioengineering and biotechnology as an interdisciplinary field. Ethical issues and the importance of a public debate about the consequences of bionics and syn- thetic biology are discussed.
文摘In this study, a coal gasification model is developed based on nine simultaneous reactions. For given gasification temperature and pressure, the air/fuel and water vapor/fuel ratio are optimized for maximum H2/CO ratio by parametric study. Furthermore, the cold gas efficiency and higher heating value of the synthesis gas produced are computed for each case. Optimum locations of investigated parameters are also searched for maximizing cold gas efficiency and higher heating value of the synthesis gas.
