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00608 Large-scale synthesis of artificial zeolite from coal fly ash with a small charge of alkaline solution
04 By-products related to fuels and 150:C, Ge extraction yields were k e p t at similar levels, while reducing the content of impurities, the water/fly ash ratio and extraction time. The e x p e r i m e n t a l data point out the influence of chloride, calcium and sulfide dissolutions on the Ge extraction.
06•00608 Large-scale synthesis of artificial zeolite from coal fly ash with a small charge of alkaline solution Moriyama, R. et al. Fuel, 2005, 84, (12 137, 1455 1461. A new process for converting coal fly ash to an artificial zeolite is described. The process is comprised of a h i g h - t e m p e r a t u r e operation and water removal d u r i n g the operation. Suitable operation p a r a m e t e r s of the process were investigated using a test unit, and the optimal conditions were found to be 2.5 3.5 mol/dm3 of N a O H and 0.88 1.10 dm3/kg of liquid/solid, sodium hydroxide charge from 2.2 to 3.9 mol/kgCFA. The zeolites obtained from a pilot plant had a higher cation exchangeable capacity than those from the test unit and were c o m p a r a b l e to zeolites p r e p a r e d using a conventional method.
06•00609 Latent heat thermal energy storage tanks for space heating of buildings: Comparison between calculations and experiments H a m a d a , Y. and Fukai, J. Energy Conversion and Management, 2005, 46, (207, 3221 3235. L a t e n t heat t h e r m a l energy storage tanks, where carbon fibre brushes are inserted to improve the heat transfer rates in the phase change materials, are installed in an air conditioning system of a building as a space heating resource. The m e a s u r e d outlet fluid t e m p e r a t u r e s are c o m p a r e d with the n u m e r i c a l ones predicted by a previously developed t h r e e - d i m e n s i o n a l heat transfer model. The preliminary n u m e r i c a l results had unallowable prediction errors, which probably resulted from poor contact between the brushes and the heat transfer tubes due to an installation problem of the brushes. However, the n u m e r i c a l results predicted by a corrected m o d e l agree well with the e x p e r i m e n t a l ones under various operating conditions. The effect of the brushes on the t h e r m a l outputs of the tanks is then investigated using the corrected model. The result shows that the brushes contribute to saving space and reducing the cost of the tanks.
06•00610 Mechanistic prediction of ash deposition in a pilot-scale test facility Rushdi, A. et al. Fuel, 2005, 84, (107, 1246 1258. A mechanistic approach has been used for assessing the ash deposition tendency and has been used for predicting the ash deposition behaviour of A u s t r a l i a n b i t u m i n o u s coals in a pilot-scale test furnace. The detailed analysis of m i n e r a l m a t t e r in coal d e t e r m i n e d by Q E M S C A N analytical technique was incorporated into an ash formation model to estimate the character of ash particles. The detailed chemical composition and particle size distribution data of ash particles from the ash formation m o d e l were incorporated into a c o m p u t a t i o n a l fluid dynamics (CFD) code to get the arrival rate and retention ability of each ash particle onto the heat transfer surfaces. The C F D code along with the ash character from the ash formation m o d e l was able to simulate trends in ash deposition along the furnace length similar to those in the test furnace. The approach was also able to distinguish coals with high ash deposition potential from low ash deposition problems and the results agreed with those in test furnace.
06•00611 Microwave-assisted zeolite synthesis from coal fly ash in hydrothermal process Inada, M. et al. Fuel, 2005, 84, (12 137, 1482 1486. Coal fly ashes, which include much a m o u n t of silica and alumina, can be converted into zeolite by h y d r o t h e r m a l alkaline treatment. In the present work, the effect of microwave irradiation on the zeolite formation was investigated with emphasis on the change in yield of zeolite during the reaction. The fly ash was mixed with 2 M N a O H solution and h e a t e d by oil bath or microwave for 2 h. Zeolite Na-P1 formed after the conventional t r e a t m e n t using oil bath, but no zeolitic product was obtained by microwave heating. W h e n microwave was applied in the course of h y d r o t h e r m a l treatment, zeolitization was p r o m o t e d by the early-stage irradiation. This is due to the stimulated dissolution of SiO2 and A1203 from coal fly ash. On the other hand, the microwave irradiation in the middle to later stage r e t a r d e d the crystallization of zeolite. The microwave is effective to produce the zeolite from coal fly ash in a short period by control of irradiation schedule in the early stage.
06•00612 Mineral matter-organic matter association characterisation by QEMSCAN and applications in coal utilisation Liu, Y. et al. Fuel, 2005, 84, (107, 1259 1267. The association of m i n e r a l m a t t e r with organic matter is extremely i m p o r t a n t for coal utilization process such as pf coal combustion. With the d e v e l o p m e n t of advanced analytical instruments such as Q E M S CAN, it is now possible to measure directly the mineral matter organic m a t t e r association on a particle-by-particle basis. The m i n e r a l matter
94
Fuel and Energy Abstracts
March 2006
and m i n e r a l organic associations of a suite of fourteen CCSD coal b a n k coals (as pf) have been d e t e r m i n e d by Q E M S C A N . A n interface program was developed to m a k e Q E M S C A N data compatible with the C C S E M - b a s e d ash formation model developed previously in CCSD. Size and chemistry of flyash was predicted by a partial coalescence submodel for included m i n e r a l grains, and a f r a g m e n t a t i o n sub-model for excluded mineral grains, respectively. The size and chemistry of predicted flyash was estimated on a particle-by-particle basis, and was used to r a n k the ash effect on heat transfer reduction for all the CCSD coals using the C C S E M - b a s e d model, in which coal property, furnace geometry and operational conditions have been t a k e n into account. O t h e r applications and further developments of the technique are also outlined.
06/00613 carbons
On the determination of surface areas in activated
Stoeckli, F. and Centeno, T. A. Carbon, 2005, 43, (67, 1184 1190. The paper examines the validity of two a p p r o a c h e s frequently used to d e t e r m i n e surface areas in activated carbons, namely the B E T m e t h o d and the use of immersion calorimetry. The study is based on 21 wellcharacterized carbons, whose external and microporous surface areas, Se and Sin1, have been determined by a variety of independent techniques. It appears clearly that SBET and the real surface area Sin1 + Se are in agreement only for carbons with average pore widths Lo a r o u n d 0.8 1.1 nm. Beyond, SBET increases rapidly and SBET Se is practically the monolayer equivalent of the micropore volume ~{'o. This confirms that a characterization of surface properties based on SBET is, a priori, not reliable. The study of the enthalpy of immersion of the carbons into benzene at 293 K, based on D u b i n i n ' s theory, shows that -~iH consists of three contributions, namely from the interactions with the micropore walls ( 0.136 J m 2 7, t h e ' e x t e r n a l surface ( 0.114 J m 27, and from the volume of liquid found between the surface layers in the micropores ( 141 J c m 37. It appears that for carbons where Lo > 1 nm, the real surface area cannot be determined in a reliable way from the enthalpy of immersion and a specific heat of wetting alone.
06•00614 Physico-chemical characteristics of European pulverized coal combustion fly ashes Moreno, N. et al. Fuel, 2005, 84, (117, 1351 1363. Fly ashes sourced from E u r o p e a n pulverized coal b u r n i n g power plants (from Spain, The Netherlands, Italy and Greece) were characterized in terms of their chemical composition, mineralogy and physical properties. The a m o u n t and composition of the glass present in the ashes were also determined. The materials analysed have very different compositions and were selected with a view to d e t e r m i n i n g their suitability for different applications and for further studies on applications. The results were c o m p a r e d to the literature to d e t e r m i n e their similarities to U K coal fly ashes. Chemical analysis has enabled the categorization of the ashes based on their oxide contents. Devitrification of the glass phase has been effected using suitable heat t r e a t m e n t s and crystal phases formed are used as an indicator of glass reactivity. Based on leaching tests, certain ashes were identified as having limitations for some further uses due to the relatively high levels of leachable trace elements. A wide range of physical properties such as density were observed and these are related to factors such as mineralogical content and particle morphology.
06•00615
Pitch/coke wetting behaviour
Rocha, V. G. et al. Fuel, 2005, 84, (12 137, 1550 1556. The m e c h a n i s m s of pitch/coke interactions at the mixing stage were studied by a spreading drop test, using a bed of calcined p e t r o l e u m coke as substrate. For this purpose, three p e t r o l e u m pitches and a binder coal tar pitch, which was selected as a reference, were used. The results show that pitch wetting behaviour is related to both pitch surface tension and pitch viscosity. Low values of surface tension and viscosity are required for the pitch to spread and p e n e t r a t e into the coke bed at t e m p e r a t u r e s below 160:C. The non-wetting behaviour observed in some p e t r o l e u m pitches was ascribed to oxidation processes, as d e m o n s t r a t e d by the fact that the non-wetting pitch behaviour can be improved by using an inert a t m o s p h e r e and/or increasing the heating rate d u r i n g the spreading drop test. A d d i t i o n ally, the use of blends of wetting and non-wetting pitches and the addition of active surface agents contributes significantly to modifying the wetting behaviour of non-wetting pitches. F r o m the results obtained, a relationship between surface t e n s i o n ~ i s c o s i t y and pitch wetting behaviour was established.
06•00616 Preparation and characterization of composite electrodes of coconut-shell-based activated carbon and hydrous ruthenium oxide for supercapacitors Dandekar, M. S. et al. Journal o f Power Sources, 2005, 141, (1), 198 203. The relationship between the structure-specific capacitance (F g 1) of a composite electrode consisting of activated coconut-shell carbon and hydrous r u t h e n i u m oxide (RuO~(OH)v) has been evaluated by
06•00608 Large-scale synthesis of artificial zeolite from coal fly ash with a small charge of alkaline solution Moriyama, R. et al. Fuel, 2005, 84, (12 137, 1455 1461. A new process for converting coal fly ash to an artificial zeolite is described. The process is comprised of a h i g h - t e m p e r a t u r e operation and water removal d u r i n g the operation. Suitable operation p a r a m e t e r s of the process were investigated using a test unit, and the optimal conditions were found to be 2.5 3.5 mol/dm3 of N a O H and 0.88 1.10 dm3/kg of liquid/solid, sodium hydroxide charge from 2.2 to 3.9 mol/kgCFA. The zeolites obtained from a pilot plant had a higher cation exchangeable capacity than those from the test unit and were c o m p a r a b l e to zeolites p r e p a r e d using a conventional method.
06•00609 Latent heat thermal energy storage tanks for space heating of buildings: Comparison between calculations and experiments H a m a d a , Y. and Fukai, J. Energy Conversion and Management, 2005, 46, (207, 3221 3235. L a t e n t heat t h e r m a l energy storage tanks, where carbon fibre brushes are inserted to improve the heat transfer rates in the phase change materials, are installed in an air conditioning system of a building as a space heating resource. The m e a s u r e d outlet fluid t e m p e r a t u r e s are c o m p a r e d with the n u m e r i c a l ones predicted by a previously developed t h r e e - d i m e n s i o n a l heat transfer model. The preliminary n u m e r i c a l results had unallowable prediction errors, which probably resulted from poor contact between the brushes and the heat transfer tubes due to an installation problem of the brushes. However, the n u m e r i c a l results predicted by a corrected m o d e l agree well with the e x p e r i m e n t a l ones under various operating conditions. The effect of the brushes on the t h e r m a l outputs of the tanks is then investigated using the corrected model. The result shows that the brushes contribute to saving space and reducing the cost of the tanks.
06•00610 Mechanistic prediction of ash deposition in a pilot-scale test facility Rushdi, A. et al. Fuel, 2005, 84, (107, 1246 1258. A mechanistic approach has been used for assessing the ash deposition tendency and has been used for predicting the ash deposition behaviour of A u s t r a l i a n b i t u m i n o u s coals in a pilot-scale test furnace. The detailed analysis of m i n e r a l m a t t e r in coal d e t e r m i n e d by Q E M S C A N analytical technique was incorporated into an ash formation model to estimate the character of ash particles. The detailed chemical composition and particle size distribution data of ash particles from the ash formation m o d e l were incorporated into a c o m p u t a t i o n a l fluid dynamics (CFD) code to get the arrival rate and retention ability of each ash particle onto the heat transfer surfaces. The C F D code along with the ash character from the ash formation m o d e l was able to simulate trends in ash deposition along the furnace length similar to those in the test furnace. The approach was also able to distinguish coals with high ash deposition potential from low ash deposition problems and the results agreed with those in test furnace.
06•00611 Microwave-assisted zeolite synthesis from coal fly ash in hydrothermal process Inada, M. et al. Fuel, 2005, 84, (12 137, 1482 1486. Coal fly ashes, which include much a m o u n t of silica and alumina, can be converted into zeolite by h y d r o t h e r m a l alkaline treatment. In the present work, the effect of microwave irradiation on the zeolite formation was investigated with emphasis on the change in yield of zeolite during the reaction. The fly ash was mixed with 2 M N a O H solution and h e a t e d by oil bath or microwave for 2 h. Zeolite Na-P1 formed after the conventional t r e a t m e n t using oil bath, but no zeolitic product was obtained by microwave heating. W h e n microwave was applied in the course of h y d r o t h e r m a l treatment, zeolitization was p r o m o t e d by the early-stage irradiation. This is due to the stimulated dissolution of SiO2 and A1203 from coal fly ash. On the other hand, the microwave irradiation in the middle to later stage r e t a r d e d the crystallization of zeolite. The microwave is effective to produce the zeolite from coal fly ash in a short period by control of irradiation schedule in the early stage.
06•00612 Mineral matter-organic matter association characterisation by QEMSCAN and applications in coal utilisation Liu, Y. et al. Fuel, 2005, 84, (107, 1259 1267. The association of m i n e r a l m a t t e r with organic matter is extremely i m p o r t a n t for coal utilization process such as pf coal combustion. With the d e v e l o p m e n t of advanced analytical instruments such as Q E M S CAN, it is now possible to measure directly the mineral matter organic m a t t e r association on a particle-by-particle basis. The m i n e r a l matter
94
Fuel and Energy Abstracts
March 2006
and m i n e r a l organic associations of a suite of fourteen CCSD coal b a n k coals (as pf) have been d e t e r m i n e d by Q E M S C A N . A n interface program was developed to m a k e Q E M S C A N data compatible with the C C S E M - b a s e d ash formation model developed previously in CCSD. Size and chemistry of flyash was predicted by a partial coalescence submodel for included m i n e r a l grains, and a f r a g m e n t a t i o n sub-model for excluded mineral grains, respectively. The size and chemistry of predicted flyash was estimated on a particle-by-particle basis, and was used to r a n k the ash effect on heat transfer reduction for all the CCSD coals using the C C S E M - b a s e d model, in which coal property, furnace geometry and operational conditions have been t a k e n into account. O t h e r applications and further developments of the technique are also outlined.
06/00613 carbons
On the determination of surface areas in activated
Stoeckli, F. and Centeno, T. A. Carbon, 2005, 43, (67, 1184 1190. The paper examines the validity of two a p p r o a c h e s frequently used to d e t e r m i n e surface areas in activated carbons, namely the B E T m e t h o d and the use of immersion calorimetry. The study is based on 21 wellcharacterized carbons, whose external and microporous surface areas, Se and Sin1, have been determined by a variety of independent techniques. It appears clearly that SBET and the real surface area Sin1 + Se are in agreement only for carbons with average pore widths Lo a r o u n d 0.8 1.1 nm. Beyond, SBET increases rapidly and SBET Se is practically the monolayer equivalent of the micropore volume ~{'o. This confirms that a characterization of surface properties based on SBET is, a priori, not reliable. The study of the enthalpy of immersion of the carbons into benzene at 293 K, based on D u b i n i n ' s theory, shows that -~iH consists of three contributions, namely from the interactions with the micropore walls ( 0.136 J m 2 7, t h e ' e x t e r n a l surface ( 0.114 J m 27, and from the volume of liquid found between the surface layers in the micropores ( 141 J c m 37. It appears that for carbons where Lo > 1 nm, the real surface area cannot be determined in a reliable way from the enthalpy of immersion and a specific heat of wetting alone.
06•00614 Physico-chemical characteristics of European pulverized coal combustion fly ashes Moreno, N. et al. Fuel, 2005, 84, (117, 1351 1363. Fly ashes sourced from E u r o p e a n pulverized coal b u r n i n g power plants (from Spain, The Netherlands, Italy and Greece) were characterized in terms of their chemical composition, mineralogy and physical properties. The a m o u n t and composition of the glass present in the ashes were also determined. The materials analysed have very different compositions and were selected with a view to d e t e r m i n i n g their suitability for different applications and for further studies on applications. The results were c o m p a r e d to the literature to d e t e r m i n e their similarities to U K coal fly ashes. Chemical analysis has enabled the categorization of the ashes based on their oxide contents. Devitrification of the glass phase has been effected using suitable heat t r e a t m e n t s and crystal phases formed are used as an indicator of glass reactivity. Based on leaching tests, certain ashes were identified as having limitations for some further uses due to the relatively high levels of leachable trace elements. A wide range of physical properties such as density were observed and these are related to factors such as mineralogical content and particle morphology.
06•00615
Pitch/coke wetting behaviour
Rocha, V. G. et al. Fuel, 2005, 84, (12 137, 1550 1556. The m e c h a n i s m s of pitch/coke interactions at the mixing stage were studied by a spreading drop test, using a bed of calcined p e t r o l e u m coke as substrate. For this purpose, three p e t r o l e u m pitches and a binder coal tar pitch, which was selected as a reference, were used. The results show that pitch wetting behaviour is related to both pitch surface tension and pitch viscosity. Low values of surface tension and viscosity are required for the pitch to spread and p e n e t r a t e into the coke bed at t e m p e r a t u r e s below 160:C. The non-wetting behaviour observed in some p e t r o l e u m pitches was ascribed to oxidation processes, as d e m o n s t r a t e d by the fact that the non-wetting pitch behaviour can be improved by using an inert a t m o s p h e r e and/or increasing the heating rate d u r i n g the spreading drop test. A d d i t i o n ally, the use of blends of wetting and non-wetting pitches and the addition of active surface agents contributes significantly to modifying the wetting behaviour of non-wetting pitches. F r o m the results obtained, a relationship between surface t e n s i o n ~ i s c o s i t y and pitch wetting behaviour was established.
06•00616 Preparation and characterization of composite electrodes of coconut-shell-based activated carbon and hydrous ruthenium oxide for supercapacitors Dandekar, M. S. et al. Journal o f Power Sources, 2005, 141, (1), 198 203. The relationship between the structure-specific capacitance (F g 1) of a composite electrode consisting of activated coconut-shell carbon and hydrous r u t h e n i u m oxide (RuO~(OH)v) has been evaluated by