Concept for a competitive coal fired integrated gasification combined cycle power plant

Concept for a competitive coal fired integrated gasification combined cycle power plant

06 Electrical power supply and utilization (scientifk, technical) X-ray photo electron spectroscopy, and Auger electron spectroscopy. The sputtered fi...

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06 Electrical power supply and utilization (scientifk, technical) X-ray photo electron spectroscopy, and Auger electron spectroscopy. The sputtered film was annealed at different temperatures. This paper also presents the results obtained on the microstructure, chemistry and the thermal stability of the diffusion barrier layer.

due to the repeated change in lattice volume is the most important failure mode in these materials. Spine1 dissolution plays a second major role.

Design optimization and integration of nickel/ Haynes-25 AMTEC cells into radioisotope power systems

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Characterization of reaction in lithium-ion cells by calorimetry and staircase voltage, step coulometry

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Saito, Y. ef al. J. Power Sources, 1999, 81-82, 913-917. In order to characterize the reaction mechanism of lithium-ion cells during charge and discharge, two experimental methods, calorimetry and staircase voltage step coulometry, are examined. As a result of calorimetry during charge and discharge, the influence of previous treatment applied to the cell is observed in the heat generation behaviour. The staircase voltage step coulometry provides kinetic information of the rate determining step in the cell reaction. It is found that there is a slow-rate reaction besides the main cell reaction during charge and discharge. It is suggested that the irreversibility of the slowrate reaction causes the voltage hysteresis between charge and discharge. The cell reaction mechanism is discussed, mainly focusing on the reaction at the hard carbon anode used in the test cell.

W/W302 Concept for a competitive coal fired integrated gasification combined cycle power plant Campbell, P. E. er al. Fuel, 2000, 79, (9) 1031-1040. The design efficiency for a state-of-the-art supercritical coal fired pulverised fuel (p.f.) power plant (e.g. Nordjyllandsvaerket) is quoted at 47%, comoared to 43% for the most advanced existing coal-based integrated gasification combined cycle (IGCC) plants (e.g. Buggenum and Puertollano). Of course, power plant design engineers have the experience of thousands of p.f. plants to guide them, compared with a mere handful of IGCC plants. There are also climatic and feedstock reasons why the above comparison is not a fair one. However, there is no doubt that for the environmentally friendly IGCC plants to penetrate the coal based power generation market it is necessary to demonstrate improved efficiency, reduced costs and increased availability. A number of techno-economic studies have been undertaken to see what is possible for IGCC, starting from the situation at Puertollano in Spain. These studies firstly remove the differences caused by the feedstock and the climatic conditions and then go on to look at an advanced IGCC concept that has been developed based on materials, components and processes that are available now. With the advanced IGCC concept it has been shown that the efficiency can be improved to over 50%, with an investment of less than eurolOOO/kWe. Future development work on IGCC would be more profitably directed towards reducing capital costs and improving occupancy rather than efficiency improvements.

El-Genk, M. S. and Tournier, J. M. Energy _. Comers. Manage., 2000.41, (15), 1703-1728. A number of nickel/Haynes-25, vapour anode, multi-tube alkali metal thermal-to-electric conversion (AMTBC) cell designs, similar to the pluto/express series cells, were developed and optimized for improved performance. Optimization calculations investigated the effects of changing the number and length of the sodium beta-alumina solid electrolyte (BASE) tubes, the cell length and the condenser temperature on the cell’s electric power output, conversion efficiency, temperature margin and the temperatures of the BASE brazes and the -evaporator. Various options of integrating the high performance nickel/Haynes-25 cells with usPuOz general purpose heat source (GPHS) modules, into the electric power system’s configuration proposed by advanced modular power systems, were explored for satisfying an end of mission (EOM) electric power requirement of 130 W. at 28 V dc for lo- to 15-year space missions. The power systems’ integration options explored included changing the number of GPHS modules and the number of AMTEC cells in the generator and using either fresh or aged usPuOz fuel in the GPHS modules.

Divalent cation incorporated Lir,++4g #zfr+x) (M = NiO,&o~.~~): viable cathode materials for rechargeable lithium-i’on batteries 00100306

Chang, C-C. er al. J. Power Sources, 2000, 89, (l), 56-63. A new class of divalent cation incorporated materials, Li t+xjNia,7s_ Coo.&fg,Oz(i +x). corresponding to Li(Nio.7sCoo.2s)l-yMg, 6 2 Cv =x1 (1 + x)), have been successfully synthesized and electrochemically characterized. Good cyclability, high voltage durability (up to 4.4 V during charging) and high capacity (> 150 mA h/g) are the main characteristics of this class of materials. The successful introduction of the divalent cations alone on the transition metal sites hems to attain these characteristics while also maintaining a large nominal capacity of the material without the interference of the aliovalent cations on the Li sites. Good cycling behaviour at high voltages is probably due to the prevention of overcharging of the material caused by the overoxidation of the transition metal as well as the presence of divalent cations on the transition metal site. The presence of the overoxidized transition metal as well as divalent cations on the transition metal site not only increases the cycling voltage but also enhances the phase stability of the materials during cycling.

Effect of electrode arameters on charge performance of a lead-acid ce PI

00100307 W/W303 Current status of MCFC R&D program at NED0 Nakayama, T. et al. Proc. - Elecrrochem. Sot., 1999, 99-20, 2-13. The NED0 and MCFC Research Association is the main group to undertake the develooment of molten carbonated fuel cells. A 1 MWclass plant is operating at Kawagoe site for the purpose of verifying MCFC power generation system. The final aim of the program is to operate- the system under ~the pressure of 5 atm with-45% thermal efficiency. The 1000 kW stacks are composed of two co-flow type 250 kW stacks and two cross-flow type 250 kW stacks. The test of 1 MW olant will be carried out for x5000 hours. The 200 kW internal deforming stack is being tested in Amagasaki from June 1999 to March 2000. Broad-ranging research has also been carried out to extend fuel cell life and utilize fuel produced by gasification in the future.

De radation mechanisms in doped spinets of LiMo.05MnI.r,5 8 , (M = Li, B, Al, Co, and Ni) for Li secondary batteries Lee, J. H. et al. J. Power Sources, 2000, 89, (1) 7-14. W/W304

Spine1 lithium manganese oxides with a nominal composition of LiMo.asMnr.ss04 (M = Mn, Li, Al, Co, Ni, or B) are prepared and their degradation mechanisms encountered in lithium secondary cells are investigated. Among the degradation mechanisms proposed in previous reports, those arising either from cation mixing or from the formation of oxygen-deficient spinels are negligible in these materials, but a certain amount of spine1 dissolution is observed. X-ray diffraction (XRD) analysis indicates that the spine1 lattice experiences an appreciable change in volume during charge-discharge cycling. The extent of this change depends on the nature of dopant. Compared to the undoped spine& the lattice expansion/contraction according to Li+ insertion/removal is more significant in the B-doped spine], but it is smaller in the case of Ni-, Co-, Al-, or Li-doped spinels. Spinels experiencing a smaller volume change maintain their structural integrity, even after prolonged cell cycling, such that there is a better capacity retention. In the B-doped spinel, however, the spine1 lattice is largely collapsed and new phases are formed after cell cycling. This results in poor cycleability. It is proposed that the structural breakdown

Kim, S. C. and Hong, W. H. J. Power Sources. 2000, 89, (l), 15-28. The charge characteristics of a lead-acid cell are observed by using a numerical simulation. The effect of various parameters, such as the concentration exponent of charge reaction, morphology parameter and limiting current density, on the cell voltage during charge has been investigated by including the dissolution-precipitation mechanism of the neeative electrode. As the chareinn current densitv is increased. the conceitration gradient is increase; &e to the high’resistance of the electrolyte migration, especially at the interface between the positive electrode and the reservoir.

OOIOO306 Effect of gelling on the impedance parameters of PblPbSO, electrode in maintenance-free lead-acid batteries Vinod, M. P. and Vijayamohanan, K. J. Power Sources, 2000, 89, (l), 88-92. The impedance parameters of Pb/PbS04 electrode in 4.8 M sulfuric acid have been measured potentiostatically under open-circuit conditions over a wide range of frequencies (lo-’ to lo4 Hz) under both deep-discharged (state-of-charge, SoC = 0) and fully charged (SoC = 1) conditions. Immobilization of the electrolyte by adding sodium silicate (5 g/l) on the impedance of Pb/PbS04 electrode shows significant difference in comparison with the flooded system. Four equivalent circuits have been formulated for overcharged and deepdischarged electrodes in gelled and flooded electrolytes, respectively. Impedance parameters are calculated using a phenomenological model, which indicates that in the case of gelled electrolytes, the electrochemical reactions are mass-transfer controlled, in contrast to the flooded electrolyte cells, where the process is known to be chargetransfer controlled. The study provides a non-destructive investigation of the effect of gelling on the electrical performance of sealed maintenance-free lead-acid batteries.

Effects of temperature and partial pressure of COz/Oa on corrosion behaviour of stainless-steel in molten LilNa carbonate salt 00/00309

Lim, T-H. et al. J. Power Sources, 2000, 89, (l), l-6. Fuel and Energy Abstracts

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