The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
M C Zhang - One of the best experts on this subject based on the ideXlab platform.
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Mass Transfer Coefficients for the Combustion of a Char Particle in O2/CO2
Energy & Fuels, 2009Co-Authors: M C ZhangAbstract:As contrasted with the Conventional Coal combustion, there are higher O2 and CO2 contents in the oxy-fuel combustion. At higher temperature, Stefan flow, due to strong nonequimolar counter-diffusion of the gas component, occurs at the surface of char and has significant effects on the char combustion. But Stefan flow is often neglected in the study of Conventional Coal combustion. In this work, two correction factors to the case of neglecting the Stefan flow are presented for the mass transfer coefficients related to the oxidation reaction, 2C + O2 → 2CO, and the reduction reaction, C + CO2 → 2CO, respectively. According to the discussions for various limiting combustion conditions, it can be seen that the correction to the mass transfer of the reduction reaction is notable, comparing to that of oxidation reaction. The correction to reduction reaction can be up to 74%, depending on the combustion rate ratio of two reactions and the ambient CO2 content. The correction to oxidation reaction also depends on ...
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mass transfer coefficients for the combustion of a char particle in o2 co2
Energy & Fuels, 2009Co-Authors: Juan Yu, M C ZhangAbstract:As contrasted with the Conventional Coal combustion, there are higher O2 and CO2 contents in the oxy-fuel combustion. At higher temperature, Stefan flow, due to strong nonequimolar counter-diffusion of the gas component, occurs at the surface of char and has significant effects on the char combustion. But Stefan flow is often neglected in the study of Conventional Coal combustion. In this work, two correction factors to the case of neglecting the Stefan flow are presented for the mass transfer coefficients related to the oxidation reaction, 2C + O2 → 2CO, and the reduction reaction, C + CO2 → 2CO, respectively. According to the discussions for various limiting combustion conditions, it can be seen that the correction to the mass transfer of the reduction reaction is notable, comparing to that of oxidation reaction. The correction to reduction reaction can be up to 74%, depending on the combustion rate ratio of two reactions and the ambient CO2 content. The correction to oxidation reaction also depends on ...
Rui Zhang - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic and economic analysis of a Coal staged conversion utilization polygeneration system
Energy technology, 2015Co-Authors: Rui ZhangAbstract:Coal polygeneration systems are recognized as promising technologies for efficient and clean Coal utilization. In previous Coal polygeneration systems, Coal was only used as a feedstock for gasification. The value difference between diverse constituents of Coal is neglected. Based on an idea to utilize the different constituents of Coal separately, a Coal staged conversion utilization polygeneration system is proposed. In this system, pyrolysis gas and tar are first extracted through Coal pyrolysis followed by char extraction. The tar is used for fuel-oil production through tar hydrogenation. The char is gasified to produce syngas. Pyrolysis gas and syngas are mixed together to produce methanol and electricity. Process simulation of this system was established by using Aspen Plus. For comparison, a Conventional Coal polygeneration system based on entrained flow gasification technology and Fischer–Tropsch synthesis technology has also been established by using Aspen Plus. Simulation results indicate that the thermal efficiency and internal rate of return of the Coal staged conversion utilization polygeneration system are higher, whereas the total capital investment and discounted payback period are lower than those of the Conventional Coal polygeneration system. The thermal efficiency of Coal staged conversion utilization polygeneration can reach 51.16 % (lower heating value).
Chuanxin Yang - One of the best experts on this subject based on the ideXlab platform.
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A novel approach to improving load flexibility of Coal-fired power plant by integrating high temperature thermal energy storage through additional thermodynamic cycle
Applied Thermal Engineering, 2020Co-Authors: Ruifeng Cao, Yufeng Guo, Weiwei Bao, Zhang Zhongbin, Chuanxin YangAbstract:Abstract This work presents a novel approach to improving the load flexibility of Coal-fired power plant by integrating high temperature thermal energy storage (HTTES) through additional thermodynamic cycle. It aims to investigate the feasibility of introducing an HTTES-aided additional cycle into the steam-water cycle of Conventional Coal-fired power plant and to test how a high round-trip efficiency can be achieved with the HTTES integration. The thermal system and operation mode of an HTTES-aided Coal-fired power plant were described. The performance evaluation model was built and its performance was discussed based on a 600 MW subcritical Coal-fired power plant model. The results show that the proposed approach is feasible to improve the load flexibility of the Conventional Coal-fired power plant. An additional net power can be obtained while the original unit works at its rated condition. The initial steam pressure of the additional cycle is the determining factor for the round-trip efficiency and a round-trip efficiency of 44.18% can be obtained. This work is expected to provide a detailed reference on the use of HTTES system to improve the load flexibility of Coal-fired power plants and further to relieve the serious problem of the curtailment for fluctuating renewable power generation in China.
James C Hower - One of the best experts on this subject based on the ideXlab platform.
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relationships between noble metals as potential Coal combustion products and Conventional Coal properties
Fuel, 2018Co-Authors: Chehreh S Chelgani, James C HowerAbstract:Abstract Increasing Coal consumption has generated million tons of ash and caused various environmental issues. Exploring statistical relationships between concentrations of valuable metals in Coal and other Coal properties may have several benefits for their commercial extraction as byproducts. This investigation studied relationships between Conventional Coal concentrations and concentration of noble metals for a wide range (708 samples) of eastern Kentucky Coal samples (EKCS) by statistical methods. The results indicate that there are significant positive Pearson correlations (r) > 0.90 among all noble metals (Au, Pt, Pd, Ru and Rh) except for Ag (r
Eric Hu - One of the best experts on this subject based on the ideXlab platform.
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multi point and multi level solar integration into a Conventional Coal fired power plant
Energy & Fuels, 2010Co-Authors: Yongping Yang, Akira Nishimura, Abbas Z Kouzani, Eric HuAbstract:Solar-aided power generation (SAPG) is capable of integrating solar thermal energy into a Conventional thermal power plant, at multi-points and multi-levels, to replace parts of steam extractions in the regenerative Rankine cycle. The integration assists the power plant to reduce Coal (gas) consumption and pollution emission or to increase power output. The overall efficiencies of the SAPG plants with different solar replacements of extraction steam have been studied in this paper. The results indicate that the solar thermal to electricity conversion efficiencies of the SAPG system are higher than those of a solar-alone power plant with the same temperature level of solar input. The efficiency with solar input at 330 °C can be as high as 45% theoretically in a SAPG plant. Even the low-temperature solar heat at about 85 °C can be used in the SAPG system to heat the lower temperature feedwater, and the solar to electricity efficiency is nearly 10%. However, the low-temperature heat resource is very hard to be used for power generation in other types of solar power plants. Therefore, the SAPG plant is one of the most efficient ways for solar thermal power generation.