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Is coal desulphurisation worthwhile? Evidence from the market
0 7 So/id fuels (derived solid fuels) Design of cost-effective coal washery effluent 02/00775 treatment plant for clean environment Ghose, M.K. J. SC;. Id. Res., 2001, 60, (I), 40-47. Coal washery effluents contain large amounts of suspended solids and high COD values and they create serious pollution problem of water in which they are discharged. The solids in suspension are colloidal in nature and possess high coking value. Thus in addition to water pollution and siltation on the river bed, good quality coking coal is being lost. It shows the ineffectiveness of the present effluent treatment system. One large coal washery has been surveyed and the characteristics of the effluent have been evaluated. Treatability study for the removal of suspended solids has been conducted. The effectiveness of the use of different conventional and synthetic polymeric flocculates for the removal of suspended solids has been evaluated. Studies also involved the identification of a suitable flocculant and development of a methodology for the effective removal of suspended solids from the effluent. A treatment scheme has been suggested which will make it feasible to design a cost-effective treatment plant for coal washery and the supernatant liquid can be recycled or safely discharged without causing surface water pollution. It would maintain the acceptable balance between environmental management and sustainable development of coal washeries in the region. 02/00776 Is coal desulphurisation worthwhile? Evidence from the market Braden, J.B. c/ (II. Energy Policy, 2001, 29, (3). 217-225. The paper develops a forward-looking way to estimate the economic benefits of research and development on coal desulphurization. The methodology makes use of survey-based techniques pioneered in environmental economics. The empirical results illustrate the difficulty of configuring desulphurized coal to meet the requirements of existing electricity generating plants. In addition to estimating the returns to investment in coal desulphurization, the contributions of the paper are in extending survey-based valuation to meet the needs of R&D investors for intelligence about the prospective value of their investments and using robust estimation techniques to reduce the influence of outliers. Perpectives of a hydrogen energy economy. Part 02lOO777 1: Techniques and systems for hydrogen production Dreier, T. and Wagner, U. BWK. Brmnsr.. Wc~cmme.Kruf,, 2000, 52, (12) 41-46. (In German) This paper outlines the perspectives of a Hr energy economy. The technical systems to produce H2 are presented, starting with the steam reforming process of light hydrocarbons with water to achieve H1 and CO?. Other sources for Hz were the partial oxidation of heavy restdues from refineries, the gasification of coal, electrolysis of water, thermal the sulfur-iodine process, solar-driven decomposition of water, thermochemical processes, photosynthetic processes, and biological processes. The digital deposit cadaster of lignite for Saxony 02/00778 Jakel, M. et cl/. Z. Gcol. Wis,s., 2000, 28, (l/2), 291-302. (In German) Saxony (Germany) owns significant resources of lignite which were extensively explored and mined in the past. Production in Saxony fell from 125 million tons in 1990 to 16 million tons in 1998 with no hope of a speedy recovery. From 18 open pit mines in 1989, three or four will remain after 1999. Therefore, it seemed reasonable to document the state of knowledge about the lignite occurrences in Saxony and make it available for government planning purposes to protect those deposits which could become mineable again in a more distant future. The Saxony State Agency for Environment and Geology eventually contracted among other consultants the CEOS Engineering Company to set up a lignite deposit information system based on a jointly designed conception. The data source is mainly from a lignite reconnaissance and prospecting program of the 1980s. Building the ‘lignite deposit register’ went along with re-design and re-assessment of all resources outside those three major coalfields in which active mining will continue. In Saxony I8 seam complexes occur within II4 coalfields, which again, in accordance with reserve classification, are subdivided into 768 panels. For each panel the lignite register informs about contours of seams and coalfields (designed at a 1:50000 scale); classification and vol. of resources/reserves; coal quality data; hydrogeology and geotechnology properties, Factual data and geometry data are linked by a seven-digit identification mark. The software is Access for the data base and ArcInfoiArcView for geometry.
Derived solid fuels 02/00779 Characteristics of chars prepared from various pulverized coals at different temperatures by using droptube furnace Lu, L. et crl. Energy fir&, 2000, 14, (4) 8699876. Char samples were prepared from five Australian black coals at different temperatures using a well-characterized drop-tube furnace. The characteristics of resultant chars and their parent coals were determined by such techniques as chemical analysis, X-ray diffraction, field emission SEM, and the newly developed focused ion beam miller. Some conventional particle analytical techniques were also used. The atomic structure, physical structure, and chemistry of chars were investigated as a function of pyrolysis conditions including pyrolysis temperature and coal type. Pyrolysis temperature is one of the key parameters influencing the char atomic structure. In general, the chars become more ordered and condensed with increasing pyrolysis temperature. This could be seen in their crystallite size (Ltt), aromaticity (fa), and interlayer spacing (dn&d,). After being treated at lzOpC, the Lt , value increased from 5.9-6.5 A for raw coals to 7.810 A for the chars, and f, increased from 58-72% for ray coals to 7.882% for chars, Meanwhile donz decreased from 3.5-3.59 A for raw coals to 3.46-3.53 A forechars, and d, decreased upon charring from 4.725.01 to 4.33-4.74 A. The char atomic structure is also dependent on coal type. However, the strong dependence on volatile matter observed for raw coals is diminished for the chars. Although all chars, except chars from coal AC-5, have similar spherical morphologies and surface areas, chars from different coals demonstrate extremely different pore structure. Some chars are very porous and light, while the others are solid and dense. The chemical analysis of chars shows that the atomic ratios H/C and O/C significantly decrease with increasing pyrolysis temperature. At pyrolysis temperatures of 1200°C or greater, all the obtained chars have similar H/C and O/C ratios regardless of their origins. The decrease in H/C ratio is in agreement with the disappearance of -, band and increasing aromaticity, which were observed in char XRD spectra with increasing pyrolysis temperature. 02100780 Characterization of porosity in cokes by image analysis Rorvik, S. ef (I/. L~ghr Mel. f Wrrrren&/e, PA, L’. S.), 2001, 603-609. A fully automatic method for image analysis of porosity of cokes has been developed. The method outputs a continuous pore size distribution from I LLrn to 10 mm, and will therefore cover a larger range than mercury porosimetry. The method measures only pores inside the coke grains; voids between coke grains in the sample are ignored. A selection of calcined combined cokes in different fraction sizes has been analysed. There are considerable differences in the pore size distributions of the different cokes. 02/00781 Co-carbonization of coking coal with different waste plastics Li, D. et crl. Ron/& Hrtuslte Xurhao, 2001, 29, (I), l9--23. Using log atmospheric fixed-bed reactor, thermo-balance and polarized optical microscope, the influence of adding different waste plastics such as waste HDPE, LDPE, PP and PS on the product distribution, optical properties of coke and the thermogravimetric behaviour of a coking coal was studied. The result showed that the difference in the decomposition range and peak temperature between TC and waste plastics determined the extent of synergism between them. The addition of these four waste plastics has no obvious effect on the coke yield of TC coal. When HDPE, LDPE or PP was added into TC, the tar yield of pure TC increased and the water yields decreased. However, for waste PS, the case was just the opposite. HDPE, LDPE and PS increased the volume percentage of anisotropy, while PP did not affect the optical textures of resultant coke. 02lOO782 Coke deactivation of PdlH-mordenite catalysts used for C&/C, hydroisomerization Li, C.L. rr rrl. Appl. Curd., A, 2000, 199, (2), 211-220. Coke formation in Cs/Cs alkane isomerization on a Pd/H-Mordenite catalyst discharged from a pilot reactor was studied. XRD, EPR, MASNMR, FTIR, TGA and TPO were applied for the characterization of the coke and coked catalysts. The coke content, chemical composition, structure and nature depended on time-onstream and section of catalyst bed. The coke content increased from 3.0 wt% in the top section, to 4.1 wt% in the central section and 6.2 wt% in the bottom of the catalyst bed. The C/H ratio of the corresponding coke increased from 1 : 1.12 to I : 0.55 to 1 : 0.35, which significantly affects the catalytic behaviour and regeneration of the catalysts. The selectivity to 2,2dimethylbutane in hexane isomerization decreased from 19% for fresh catalyst, to 10% and 8.3% for coked catalyst in the central and outlet section, respectively. As time-onstream increased, coke initially formed on Pd and then moved to acidic sites in the support where polyaromatic Fuel and Energy Abstracts
March 2002
95
Derived solid fuels 02/00779 Characteristics of chars prepared from various pulverized coals at different temperatures by using droptube furnace Lu, L. et crl. Energy fir&, 2000, 14, (4) 8699876. Char samples were prepared from five Australian black coals at different temperatures using a well-characterized drop-tube furnace. The characteristics of resultant chars and their parent coals were determined by such techniques as chemical analysis, X-ray diffraction, field emission SEM, and the newly developed focused ion beam miller. Some conventional particle analytical techniques were also used. The atomic structure, physical structure, and chemistry of chars were investigated as a function of pyrolysis conditions including pyrolysis temperature and coal type. Pyrolysis temperature is one of the key parameters influencing the char atomic structure. In general, the chars become more ordered and condensed with increasing pyrolysis temperature. This could be seen in their crystallite size (Ltt), aromaticity (fa), and interlayer spacing (dn&d,). After being treated at lzOpC, the Lt , value increased from 5.9-6.5 A for raw coals to 7.810 A for the chars, and f, increased from 58-72% for ray coals to 7.882% for chars, Meanwhile donz decreased from 3.5-3.59 A for raw coals to 3.46-3.53 A forechars, and d, decreased upon charring from 4.725.01 to 4.33-4.74 A. The char atomic structure is also dependent on coal type. However, the strong dependence on volatile matter observed for raw coals is diminished for the chars. Although all chars, except chars from coal AC-5, have similar spherical morphologies and surface areas, chars from different coals demonstrate extremely different pore structure. Some chars are very porous and light, while the others are solid and dense. The chemical analysis of chars shows that the atomic ratios H/C and O/C significantly decrease with increasing pyrolysis temperature. At pyrolysis temperatures of 1200°C or greater, all the obtained chars have similar H/C and O/C ratios regardless of their origins. The decrease in H/C ratio is in agreement with the disappearance of -, band and increasing aromaticity, which were observed in char XRD spectra with increasing pyrolysis temperature. 02100780 Characterization of porosity in cokes by image analysis Rorvik, S. ef (I/. L~ghr Mel. f Wrrrren&/e, PA, L’. S.), 2001, 603-609. A fully automatic method for image analysis of porosity of cokes has been developed. The method outputs a continuous pore size distribution from I LLrn to 10 mm, and will therefore cover a larger range than mercury porosimetry. The method measures only pores inside the coke grains; voids between coke grains in the sample are ignored. A selection of calcined combined cokes in different fraction sizes has been analysed. There are considerable differences in the pore size distributions of the different cokes. 02/00781 Co-carbonization of coking coal with different waste plastics Li, D. et crl. Ron/& Hrtuslte Xurhao, 2001, 29, (I), l9--23. Using log atmospheric fixed-bed reactor, thermo-balance and polarized optical microscope, the influence of adding different waste plastics such as waste HDPE, LDPE, PP and PS on the product distribution, optical properties of coke and the thermogravimetric behaviour of a coking coal was studied. The result showed that the difference in the decomposition range and peak temperature between TC and waste plastics determined the extent of synergism between them. The addition of these four waste plastics has no obvious effect on the coke yield of TC coal. When HDPE, LDPE or PP was added into TC, the tar yield of pure TC increased and the water yields decreased. However, for waste PS, the case was just the opposite. HDPE, LDPE and PS increased the volume percentage of anisotropy, while PP did not affect the optical textures of resultant coke. 02lOO782 Coke deactivation of PdlH-mordenite catalysts used for C&/C, hydroisomerization Li, C.L. rr rrl. Appl. Curd., A, 2000, 199, (2), 211-220. Coke formation in Cs/Cs alkane isomerization on a Pd/H-Mordenite catalyst discharged from a pilot reactor was studied. XRD, EPR, MASNMR, FTIR, TGA and TPO were applied for the characterization of the coke and coked catalysts. The coke content, chemical composition, structure and nature depended on time-onstream and section of catalyst bed. The coke content increased from 3.0 wt% in the top section, to 4.1 wt% in the central section and 6.2 wt% in the bottom of the catalyst bed. The C/H ratio of the corresponding coke increased from 1 : 1.12 to I : 0.55 to 1 : 0.35, which significantly affects the catalytic behaviour and regeneration of the catalysts. The selectivity to 2,2dimethylbutane in hexane isomerization decreased from 19% for fresh catalyst, to 10% and 8.3% for coked catalyst in the central and outlet section, respectively. As time-onstream increased, coke initially formed on Pd and then moved to acidic sites in the support where polyaromatic Fuel and Energy Abstracts
March 2002
95