- Email: [email protected]
00407 A regenerable copper-based sorbent for H2S removal from coal gases
04 Interfacial ’microstructures of intrabundle in as99100398 received carbon/carbon composites prepared by CVI Shi, R. et al. Carbon, 1998, 36, (9), 1331-1335. Using high-resolution electron microscopy a detailed study of the interfacial microstructures of the intrabundles in as-received carbon/carbon composites prepared by CVI was performed. Chosen for comparison were two kinds of carbon fibres, high strength carbon fibre T300 and high modulus carbon fibre T-50. It was discovered that the interface between the carbon fibre and carbon matrix is not simply a mechanical pinning structure formed by pyrolytic carbons directly contacting the rough carbon fibre surface. Instead, a transitional interfacial layer between the carbon fibres and the pyrolytic carbon matrix was observed which is referred to as induced microstructure. The graphitic degree and the crystallite size of the carbon fibre surface markedly affect the induced interfacial microstructures. The more regular and graphitic the carbon fibre surface, the more ordered and thicker the interface layer induced. Mathematical modeling of fluidized bed coal 99100399 gasifiers Yan, H.-M. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1997, 14, (8), 819. To simulate performance of bubbling fluidized-bed coal gasifiers of various scales a steady-state isothermal model has been developed. Building on the two-phase fluidization theory, the model considers a comprehensive chemical reaction scheme that would occur in coal gasification processes. A net flow term from the emulsion phase to the bubble phase is introduced into the conservation equation to consider the effect of excess gases generated due to heterogeneous reactions. Comparisons of predictions are favourable. The current model is capable of simulating pressurized fluidized-bed coal gasifiers. Comparisons of the performance of the current model with two models reported in the literature indicate that the current model achieves a better agreement with the experimental data. Furthermore, simulations also indicate (i) the water-gas shift reaction has little effect on the performance of the commercial scale gasifier but has a significant effect on the pilot-scale gasifiers; (ii) The contribution of char combustion to the overall carbon conversion is not as significant, and the contribution of char gasification to the overall carbon conversion is not as small, as previously claimed in the literature; (iii) only about 26-40% of oxygen consumed by char combustion reaction. Mathematical simulation of a two stage entrained 99/00400 flow coal gasifier Chen, C. et al. Proc. Annu. Int. Pittsburgh Coal Conf, 1997, 14, (2), 26-34. For a pressurized air blown entrained flow coal gasifier with recycle char a detailed simulation was developed. In the model, the coal devolatilization, volatile and char combustion, H,O-char and COz-char gasification, and gas phase shift reaction were taken into account both in the combustor and in the reductor in accordance with the actual process. The combustor was assumed to be a well-stirred reactor with uniform gas composition and gasparticle temperature (the flame temperature). The gas concentration profiles in the reductor were predicted by considering the gas and particle temperature distribution, which were calculated by a two-dimensional heat transfer model and a Monte-Carlo radiation sub-model. The model was applied to simulate the performance characteristics of the two gasifiers so far tested in Japan. The effects of air/coal ratio, coal and air partition between combustor and reductor on the gasifier performance, such as the carbon conversion, the cold gas efficiency and heating value of the product gas, were predicted well by the model. A method of predicting the rate of ash carry-over 99100401 from PFBC Oki, K. et al. Proc. Int. Conf. Fluid. Bed Cornbust., 1997, 14, (2), 715-721. A semi-empirical method has been developed to estimate amounts of coal/ limestone ash carry-over from PFBC in order to predict ash mass balance necessary for designing PFBC ash handling systems. Based on this method, a variety of data taken with our 4-MW PFBC and those reported in the Grimethorpe PFBC have been analysed. Inputs to the method are: (1) coal and limestone feed rates, coal and limestone ash characteristics, coal-ash and limestone particle size distributions: (2) fluidized bed conditions, and geometrical dimensions of the bed; and (3) conditions related to combustion performance such as combustion efficiency, sulfur retention, and the degree of limestone calcination. With those parameters and characteristics given, it is possible to estimate whether or not the bed ash should be withdrawn from the bed or extra limestone should be fed into the bed to maintain the bed inventory, thus keeping the bed height at a constant value during steady state operations. The method can also predict concentrations of the calcium related components and the coal ash in elutriated dust particles. Described is the underlying concept for the method and parameter estimation. investigation of Microscopic carbonaceous 99100402 reactors substances formed in coal liquefaction Okada, Y. et al. Nippon Enerugi Gakkaishi, 1998, 77, (S), 410-422. (In Japanese) Attention was given to coal particles and coal-derived materials that are Hated and/or carbonized in the liquefaction reactors for the purpose of revealing the progress of coal liquefaction at the reaction fields; and an evaluation was attempted using microscopic technique. On the basis of microscopic textures and optical properties, carbonaceous substances in
By-products
related fo fuels
withdrawing from reactor bottom could be classified into five categories that include vitroplast, mesophase/anisotropic semicoke, non-plastic and partially plastic coal particle, pyrolytic carbon like material and vitrinite remnant, and its microscopic compositions were clarified. Furthermore, the effects of operating conditions on the properties of carbonaceous substances from the principally reflectance of non-plastic coal particle were researched. Consequently, when the severity of operating conditions was raised, the properties of carbonaceous substances indicated that carbonization was superior to Hation under the atmosphere of initial liquefaction stage. As the reaction proceeded, Hation became to predominant over carbonization. At high concentration coal/solvent slurry, we confirmed that H availability tended to reduce for coal particles. However. this problem could be solved by an improvement in H donor ability of recycle solvent. 99100403 Oxidation of calcium sulfide in an advanced PFBC (pressurized fluidized-bed coal combustion) cycle-effect of O2 concentration and particle size on CaS oxidation Ninomiya, Y.et al. Proc. Int. Conf Fluid. Bed Combust, 1997, 14, (I), 387396. Obtained by sulfidation of limestone the oxidation reactivity of CaS samples was investigated by using a thermal analyser (TG-DTA). The experiments were conducted with different particle sizes of the sorbent samples from 0.2 to 0.88 mm at reaction temperatures of 900 to 1350” in atmospheres containing 1 to 21% of O2 in Nz. The complete conversion of CaS in the fine particles to CaO and CaS04 was achieved at 930” with a reaction time of -400 min under 1% O2 conditions. Dependent on 02 concentration and particle size under low oxidizing conditions were the apparent reaction rates of the CaS samples. On the other hand, the reaction scarcely occurred (with lower conversion) below 1050” for higher 02 conditions, because the outside shell of the sample became covered with a CaS04 product layer and the oxidation reaction ceased due to increasing intraparticle diffusion resistance to the reactant gas. However, above 1180”, CaS in the sample was essentially converted to CaO and CaS04 at all experimental conditions in this study. Ozone treatment of carbon fibre for reinforcing 99100404 cement Xuli, F. et al. Carbon, 1998, 36, (Y), 1337-1345. It was found that ozone treatment of isotropic-pitch-based carbon fibre increases the surface oxygen concentration and change surface oxygen from C-O to C=O, thereby causing the contact angle between fibre and water to be decreased to zero. As a result, the bond strength between fibre and cement paste was increased and the.tensile strength, modulus and ductility of carbon fibre reinforced cement paste were increased. Also increased was the degree of dispersion of fibres in mortar and the effectiveness of the fibres for reducing the drying shrinkage was improved. Thus, the strain sensing ability of carbon fibre reinforced mortar was improved in terms of increased gauge factor and better repeatability. 99100405 Prediction of environmental quality of byproducts of coal-fired power plants. Elemental composition and leaching Meij, R. Stud. Environ. Sci., 1997, 71, 31 l-325. The elemental compositions of various streams of coal-fired power plants in the Netherlands are well recorded. The information of these studies is used to calculate enrichment factors for the trace elements in ash, the vaporization percentage of minor and trace elements in flue gases, the degree of removal of gaseous minor and trace elements from flue gases in flue-gas desulfurization installations and the leaching percentage of the elements in ash. These relative parameters combined with trace-element analyses of the coals are used to predict the concentrations of trace elements in the ash, in the leachate and in the flue gases in the gaseous phase. 99lOO408 Preparation of conductive carbon-ceramic composites from coal tar pitch and ceramic monoliths AlcaAiz-Monge, J. et al. Carbon, 1998, 36, (718). 1003-1009. Using coal tar pitch and a ceramic already moulded as a monolith with a honeycomb structure conductive carbon ceramic composites have been prepared. The starting ceramic and the composites have been characterized by scanning electron microscopy, EDX, thermogravimetry and X-ray diffraction. Conductivity measurements and electrochemical behaviour have been also carried out. The results obtained reveal that the highest conductivities are obtained in those samples heated to the maximum temperature studied. Stability towards oxygen increases with treatment temperature, reaching the samples treated to 1273 K for 2 hours. Additionally, the composites exhibit a high electrochemical stability that makes these materials very promising to be used as electrodes and or as electrocatalysts support. 99100407 A regenerable copper-based sorbent for H2S removal from coal gases Abbasian, J. and Slimane, R. B. Ind. Eng. Chemical Res., 1998, 37, (7), 2775-2782. Reported in this paper is research conducted for the development of copper-based sorbents for hot coal gas desulfurization applications in the temperature range of 55&65O”C. A thermodynamic analysis is given to rationalize the selection of chromia (CrzO& and its potential superiority to
Fuel and Energy Abstracts
January 1999
39
05 Nuclear fuels (scientific, technical) alumina (A&03), for the stabilization of copper oxide (C&O) against complete reduction to elemental copper (Cu) upon exposure to a fuel gas in the indicated temperature range. The results of packed-bed experiments carried out for the determination of optimum operating conditions as well as the evaluation of the long-term durability and regenerability of a selected copper chromite sorbent are presented and discussed. The regenerable copper chromite sorbent developed, designated as CuCr-29, is capable of achieving less than 5 ppmv HZ5 concentration in the cleaned fuel gas. The optimum desulfurization temperature in terms of sorbent efficiency and utilization for this sorbent is determined to be about 600°C. With a diluted 02-N* gas mixture at 750°C sorbent regeneration ensured complete conversion of the copper sulfide to oxide without sulfate formation or reactivity deterioration in subsequent cycles.
Research 99190409 desulfurlration
progress
of
high
temperature
Li, F. et al. Meiran Zhuanhua, 1997, 20, (2), 44-48. (In Chinese) Research progress of high temperature desulfurization is reviewed, including the development of several attractive mixed-metal agents for high temperature coal-gas desulfurization, the significant potential importance of high temperature desulfurization, and several suggestions for carrying out research work on high temperature desulfurization in China.
On the simulation 99/00409 pulverized coal-fired furnaces
of
the
gas-solid
flow
In
FED, 1996, 236, (l), 239-244. of the two phase flow of gas and coal particles has been carried out by the computer code FLOREAN (for the threedimensional simulation of the flow field, the heat transfer and the chemical reactions in coal dust fired furnaces) which has been extended. Two ways have been realized to overcome the inaccuracies of the original program FLOREAN which treats both phases as a continuous phase in an Eulerian approach. One way is an Eulerian approach for the particles, where gas and particles are still regarded as a continuum in the momentum and mass balance, but in the energy balance, pyrolysis and char combustion the particles are a separate phase. Typical effects of the influence of the particle size on the coal combustion can be taken into account, if more than one size group is balanced. The other way is the expansion on a two-phase flow prediction based on a Lagrangean approach for the dispersed phase. There particle trajectories are calculated in a gas flow field in consideration of temperature and the composition of coal particles. Both phases are twoway-coupled. The two phase approach leads to an important application, which is the base for the prediction of slagging and fouling in coal dust fired furnaces. Fischer,
K. et al.
A more detailed prediction
99/w410
WOVEN
process for hot gas desulfurlzatlon
Peng, W. er al. Proc. Annu. 1~. Pirtsburgh Coal Conf., 1997, 14, (84), 1220. From 1993 the Beijing Research Institute of Coal Chemical has been The Smoven developing the Smovenprocess for hot gas desulfurization. process features sulfidation in an entrained bed, regeneration in low velocity fluidized bed or moving bed with oxygen and sorbent circulating control by gas stream. One set of small scale process development unit handling 15 m3/h of coal gas was built-up and operated. In the unit test, the regenerable metal oxide sorbent was applied for the sulfur-related components removal from coal gas, which is produced in a 100 mm in diameter fluidized bed gasifier at 5.50-650”. It was verified that regeneration directly by oxygen leads to higher concentrations of sulfur dioxide.
99lOQ413 Temperature control system for reformer in oil formation apparatus from waste plastic Hama, T. et al. Jpn. Kokai Tokkyo Koho JP 10 158,661 [98 158,661] (Cl. ClOGl/lO), 16 Jun 1998, Appl. 96/325,031,5 Dee 1996; 4 pp. (In Japanese) In this process, gas as waste plastic pyrolysis product is reformed to a low bp component. The reformer is placed on the main duct for flue gas discharged from pyrolysis furnace and uses the heat of the flue gas. Temperature control of the reformer is carried out by the following system: (1) placing a bypass line for at least a part of the flue gas in parallel to the main duct and (2) controlling flow of the flue gas to the main duct and/or the bypass line. The reformer is controlled to have appropriate temperature, so that conventional problems derived from over heat is prevented. The reformed gas is cooled to recover fuel oil. 99loo414 Trace mercury concentrations In coals and coalderived material determined by atomic absorption spectrophotometry Richaud, R. et al. Fuel, 1998, 77, (S), 359-368. During quantification the volatility of mercury can cause large errors when methods based on acid digestion are applied. In this study, mercury levels in coals have been determined by an atomic-absorption-based instrument hitherto not used with coals or coal-derived materials. The results have been compared with ‘certified’ values of reference materials. The range of solid and liquid samples studied included the Argonne Premium Coal samples and other coals, coal-derived products, biomass materials, sand and kaolin. The instrument gave correct mercury concentrations for certified reference materials. Samples of silver birch and forest residue contained similar concentrations of mercury as observed in coals; other biomass samples contained far smaller quantities of mercury. Thus, the use of biomass in power generation would not necessarily lead to any great reduction of mercury in emissions from power plant: careful selection appears necessary. Only 3% of the mercury of the original coal was detected in the filter cake (corresponding to undissolved coal and mineral matter) from a coal liquefaction pilot plant. Mercury in the original coal appears to have passed either to (i) gas formed during liquefaction or to (ii) the dissolved coal extract, possibly in the form of organometallic complexes. The presence of 0.15 ppm mercury in a coal tar pitch also suggests the organometallic retention of mercury in this fraction. From a gasification pilot plant, operating at about 930-96o”C, all solid residues have shown nearly negligible mercury, compared to the original coal, indicating that the bulk of the mercury in the feedstock was released into the product gas.
Transfer recirculated reactor
99/00415
process
in
multisolid
two-chamber
Goldman, Y. et al. HTD (Am. Sot. Mechanical Eng.), 1997, 352, (2). 231237. Experimentally investigated is the prepyrolysis of coal as a precursor to its utilization in a power plant or gas turbine. The pyrolyser, 800 mm in diameter and 1500 mm in height, consists of two concentric chambers. Coarse char particles are used like an inert medium (‘sand’ in the sequel). The char is heated in the outer chamber by an external source of heat, such as hot gases. The inner chamber is used for the pyrolysis process of fine coal powder (50 IL), that is fed into it. The heat required for the endothermic pyrolysis process is supplied by the circulating char. Cold tests conducted on the apparatus indicate that the parameters most influencing solid circulation between the chambers are: the aerosol nature of the flow, the sand seals area, and the superficial velocity. The tests show that the intensive recirculation process exists only under very limited range of flow conditions. Outside this range of conditions, sand ‘bridges’ are formed at the seals preventing proper operation. These bridges can be destroyed by strong fluidization at the inner chamber wall. Results of cold and hot tests, including parametric study of the pyrolyser performance, are presented.
Study on removal of organic sulfur compound by 99/cJ9411 modlfled activated carbon Fan, H. et al. Proc. Annu. Int. Pitrsburgh Coal Conf., 1997, 14, (3), 49-55. In this paper, the effects of water vapour and experimental temperature on removal of organic sulfur compounds by using modified activated carbon were studied. It was found that water vapour had a negative effect on removal of carbon disulfide by activated carbon impregnated with organic amine. The use of activated carbon impregnated with KzC03 for removal of carbonyl sulfide was also investigated over the temperature range 30-6o”C, the results show a favourable temperature existing at 40°C for carbonyl sulfide removal. Also offered in this paper are fixed-bed breakthrough curves for the adsorbent bed as mentioned above.
05
NUCLEAR
FUELS
Scientific, Technical Annealing of nuclear reactor pressure vessels Vassilaros,M. G. et al. Nuclear Engineering and Design, 1998, 181, (l-3).
99l00416
Sulfur measurement In refined llqulds using sulfur 99ioo412 chemllumlnescence Haydt, D. D. Proc. Annu. ISA Analysis Div. Symp., 1998, 31, 79-88. A sulfur chemiluminescence analyser has been developed to measure sulfur in refined liquids. The analyser is designed to provide on-line, real-time measurement. It employs a plunger type liquid injection valve to deliver a small amount of sample to the chemiluminescence detection system. All sulfur bearing compounds are measured as a single peak representing total sulfur. The analysis technique is valid due to the inherent equimolar response of the detection system. Analysis ranges have been measured in a variety of backgrounds including gasoline, diesel, kerosene, naphtha, alcohols. and various solvents.
40
Fuel and Energy Abstracts
January 1999
61-69. In the beltline of reactor pressure vessels (RPV) the neutron embrittlement that occurs can be managed by various techniques, but only thermal annealing can reverse the effects and result in a restoration of RPV beltline material toughness. The US Nuclear Regulatory Commission has recently revised the Code of Federal Regulations to include the use of thermal annealing of RPV for recovery of material toughness. The Annealing Rule. 10 CFR Part 50.66, has an associated Regulatory Guide 1.162 that describes the format and content of a thermal anneal report that must be submitted to the NRC prior to performing an anneal. This paper will describe the thermal annealing process including regulatory requirements in 10 CFR Part 50.66, techniques for predicting and measuring the toughness recovery,
By-products
related fo fuels
withdrawing from reactor bottom could be classified into five categories that include vitroplast, mesophase/anisotropic semicoke, non-plastic and partially plastic coal particle, pyrolytic carbon like material and vitrinite remnant, and its microscopic compositions were clarified. Furthermore, the effects of operating conditions on the properties of carbonaceous substances from the principally reflectance of non-plastic coal particle were researched. Consequently, when the severity of operating conditions was raised, the properties of carbonaceous substances indicated that carbonization was superior to Hation under the atmosphere of initial liquefaction stage. As the reaction proceeded, Hation became to predominant over carbonization. At high concentration coal/solvent slurry, we confirmed that H availability tended to reduce for coal particles. However. this problem could be solved by an improvement in H donor ability of recycle solvent. 99100403 Oxidation of calcium sulfide in an advanced PFBC (pressurized fluidized-bed coal combustion) cycle-effect of O2 concentration and particle size on CaS oxidation Ninomiya, Y.et al. Proc. Int. Conf Fluid. Bed Combust, 1997, 14, (I), 387396. Obtained by sulfidation of limestone the oxidation reactivity of CaS samples was investigated by using a thermal analyser (TG-DTA). The experiments were conducted with different particle sizes of the sorbent samples from 0.2 to 0.88 mm at reaction temperatures of 900 to 1350” in atmospheres containing 1 to 21% of O2 in Nz. The complete conversion of CaS in the fine particles to CaO and CaS04 was achieved at 930” with a reaction time of -400 min under 1% O2 conditions. Dependent on 02 concentration and particle size under low oxidizing conditions were the apparent reaction rates of the CaS samples. On the other hand, the reaction scarcely occurred (with lower conversion) below 1050” for higher 02 conditions, because the outside shell of the sample became covered with a CaS04 product layer and the oxidation reaction ceased due to increasing intraparticle diffusion resistance to the reactant gas. However, above 1180”, CaS in the sample was essentially converted to CaO and CaS04 at all experimental conditions in this study. Ozone treatment of carbon fibre for reinforcing 99100404 cement Xuli, F. et al. Carbon, 1998, 36, (Y), 1337-1345. It was found that ozone treatment of isotropic-pitch-based carbon fibre increases the surface oxygen concentration and change surface oxygen from C-O to C=O, thereby causing the contact angle between fibre and water to be decreased to zero. As a result, the bond strength between fibre and cement paste was increased and the.tensile strength, modulus and ductility of carbon fibre reinforced cement paste were increased. Also increased was the degree of dispersion of fibres in mortar and the effectiveness of the fibres for reducing the drying shrinkage was improved. Thus, the strain sensing ability of carbon fibre reinforced mortar was improved in terms of increased gauge factor and better repeatability. 99100405 Prediction of environmental quality of byproducts of coal-fired power plants. Elemental composition and leaching Meij, R. Stud. Environ. Sci., 1997, 71, 31 l-325. The elemental compositions of various streams of coal-fired power plants in the Netherlands are well recorded. The information of these studies is used to calculate enrichment factors for the trace elements in ash, the vaporization percentage of minor and trace elements in flue gases, the degree of removal of gaseous minor and trace elements from flue gases in flue-gas desulfurization installations and the leaching percentage of the elements in ash. These relative parameters combined with trace-element analyses of the coals are used to predict the concentrations of trace elements in the ash, in the leachate and in the flue gases in the gaseous phase. 99lOO408 Preparation of conductive carbon-ceramic composites from coal tar pitch and ceramic monoliths AlcaAiz-Monge, J. et al. Carbon, 1998, 36, (718). 1003-1009. Using coal tar pitch and a ceramic already moulded as a monolith with a honeycomb structure conductive carbon ceramic composites have been prepared. The starting ceramic and the composites have been characterized by scanning electron microscopy, EDX, thermogravimetry and X-ray diffraction. Conductivity measurements and electrochemical behaviour have been also carried out. The results obtained reveal that the highest conductivities are obtained in those samples heated to the maximum temperature studied. Stability towards oxygen increases with treatment temperature, reaching the samples treated to 1273 K for 2 hours. Additionally, the composites exhibit a high electrochemical stability that makes these materials very promising to be used as electrodes and or as electrocatalysts support. 99100407 A regenerable copper-based sorbent for H2S removal from coal gases Abbasian, J. and Slimane, R. B. Ind. Eng. Chemical Res., 1998, 37, (7), 2775-2782. Reported in this paper is research conducted for the development of copper-based sorbents for hot coal gas desulfurization applications in the temperature range of 55&65O”C. A thermodynamic analysis is given to rationalize the selection of chromia (CrzO& and its potential superiority to
Fuel and Energy Abstracts
January 1999
39
05 Nuclear fuels (scientific, technical) alumina (A&03), for the stabilization of copper oxide (C&O) against complete reduction to elemental copper (Cu) upon exposure to a fuel gas in the indicated temperature range. The results of packed-bed experiments carried out for the determination of optimum operating conditions as well as the evaluation of the long-term durability and regenerability of a selected copper chromite sorbent are presented and discussed. The regenerable copper chromite sorbent developed, designated as CuCr-29, is capable of achieving less than 5 ppmv HZ5 concentration in the cleaned fuel gas. The optimum desulfurization temperature in terms of sorbent efficiency and utilization for this sorbent is determined to be about 600°C. With a diluted 02-N* gas mixture at 750°C sorbent regeneration ensured complete conversion of the copper sulfide to oxide without sulfate formation or reactivity deterioration in subsequent cycles.
Research 99190409 desulfurlration
progress
of
high
temperature
Li, F. et al. Meiran Zhuanhua, 1997, 20, (2), 44-48. (In Chinese) Research progress of high temperature desulfurization is reviewed, including the development of several attractive mixed-metal agents for high temperature coal-gas desulfurization, the significant potential importance of high temperature desulfurization, and several suggestions for carrying out research work on high temperature desulfurization in China.
On the simulation 99/00409 pulverized coal-fired furnaces
of
the
gas-solid
flow
In
FED, 1996, 236, (l), 239-244. of the two phase flow of gas and coal particles has been carried out by the computer code FLOREAN (for the threedimensional simulation of the flow field, the heat transfer and the chemical reactions in coal dust fired furnaces) which has been extended. Two ways have been realized to overcome the inaccuracies of the original program FLOREAN which treats both phases as a continuous phase in an Eulerian approach. One way is an Eulerian approach for the particles, where gas and particles are still regarded as a continuum in the momentum and mass balance, but in the energy balance, pyrolysis and char combustion the particles are a separate phase. Typical effects of the influence of the particle size on the coal combustion can be taken into account, if more than one size group is balanced. The other way is the expansion on a two-phase flow prediction based on a Lagrangean approach for the dispersed phase. There particle trajectories are calculated in a gas flow field in consideration of temperature and the composition of coal particles. Both phases are twoway-coupled. The two phase approach leads to an important application, which is the base for the prediction of slagging and fouling in coal dust fired furnaces. Fischer,
K. et al.
A more detailed prediction
99/w410
WOVEN
process for hot gas desulfurlzatlon
Peng, W. er al. Proc. Annu. 1~. Pirtsburgh Coal Conf., 1997, 14, (84), 1220. From 1993 the Beijing Research Institute of Coal Chemical has been The Smoven developing the Smovenprocess for hot gas desulfurization. process features sulfidation in an entrained bed, regeneration in low velocity fluidized bed or moving bed with oxygen and sorbent circulating control by gas stream. One set of small scale process development unit handling 15 m3/h of coal gas was built-up and operated. In the unit test, the regenerable metal oxide sorbent was applied for the sulfur-related components removal from coal gas, which is produced in a 100 mm in diameter fluidized bed gasifier at 5.50-650”. It was verified that regeneration directly by oxygen leads to higher concentrations of sulfur dioxide.
99lOQ413 Temperature control system for reformer in oil formation apparatus from waste plastic Hama, T. et al. Jpn. Kokai Tokkyo Koho JP 10 158,661 [98 158,661] (Cl. ClOGl/lO), 16 Jun 1998, Appl. 96/325,031,5 Dee 1996; 4 pp. (In Japanese) In this process, gas as waste plastic pyrolysis product is reformed to a low bp component. The reformer is placed on the main duct for flue gas discharged from pyrolysis furnace and uses the heat of the flue gas. Temperature control of the reformer is carried out by the following system: (1) placing a bypass line for at least a part of the flue gas in parallel to the main duct and (2) controlling flow of the flue gas to the main duct and/or the bypass line. The reformer is controlled to have appropriate temperature, so that conventional problems derived from over heat is prevented. The reformed gas is cooled to recover fuel oil. 99loo414 Trace mercury concentrations In coals and coalderived material determined by atomic absorption spectrophotometry Richaud, R. et al. Fuel, 1998, 77, (S), 359-368. During quantification the volatility of mercury can cause large errors when methods based on acid digestion are applied. In this study, mercury levels in coals have been determined by an atomic-absorption-based instrument hitherto not used with coals or coal-derived materials. The results have been compared with ‘certified’ values of reference materials. The range of solid and liquid samples studied included the Argonne Premium Coal samples and other coals, coal-derived products, biomass materials, sand and kaolin. The instrument gave correct mercury concentrations for certified reference materials. Samples of silver birch and forest residue contained similar concentrations of mercury as observed in coals; other biomass samples contained far smaller quantities of mercury. Thus, the use of biomass in power generation would not necessarily lead to any great reduction of mercury in emissions from power plant: careful selection appears necessary. Only 3% of the mercury of the original coal was detected in the filter cake (corresponding to undissolved coal and mineral matter) from a coal liquefaction pilot plant. Mercury in the original coal appears to have passed either to (i) gas formed during liquefaction or to (ii) the dissolved coal extract, possibly in the form of organometallic complexes. The presence of 0.15 ppm mercury in a coal tar pitch also suggests the organometallic retention of mercury in this fraction. From a gasification pilot plant, operating at about 930-96o”C, all solid residues have shown nearly negligible mercury, compared to the original coal, indicating that the bulk of the mercury in the feedstock was released into the product gas.
Transfer recirculated reactor
99/00415
process
in
multisolid
two-chamber
Goldman, Y. et al. HTD (Am. Sot. Mechanical Eng.), 1997, 352, (2). 231237. Experimentally investigated is the prepyrolysis of coal as a precursor to its utilization in a power plant or gas turbine. The pyrolyser, 800 mm in diameter and 1500 mm in height, consists of two concentric chambers. Coarse char particles are used like an inert medium (‘sand’ in the sequel). The char is heated in the outer chamber by an external source of heat, such as hot gases. The inner chamber is used for the pyrolysis process of fine coal powder (50 IL), that is fed into it. The heat required for the endothermic pyrolysis process is supplied by the circulating char. Cold tests conducted on the apparatus indicate that the parameters most influencing solid circulation between the chambers are: the aerosol nature of the flow, the sand seals area, and the superficial velocity. The tests show that the intensive recirculation process exists only under very limited range of flow conditions. Outside this range of conditions, sand ‘bridges’ are formed at the seals preventing proper operation. These bridges can be destroyed by strong fluidization at the inner chamber wall. Results of cold and hot tests, including parametric study of the pyrolyser performance, are presented.
Study on removal of organic sulfur compound by 99/cJ9411 modlfled activated carbon Fan, H. et al. Proc. Annu. Int. Pitrsburgh Coal Conf., 1997, 14, (3), 49-55. In this paper, the effects of water vapour and experimental temperature on removal of organic sulfur compounds by using modified activated carbon were studied. It was found that water vapour had a negative effect on removal of carbon disulfide by activated carbon impregnated with organic amine. The use of activated carbon impregnated with KzC03 for removal of carbonyl sulfide was also investigated over the temperature range 30-6o”C, the results show a favourable temperature existing at 40°C for carbonyl sulfide removal. Also offered in this paper are fixed-bed breakthrough curves for the adsorbent bed as mentioned above.
05
NUCLEAR
FUELS
Scientific, Technical Annealing of nuclear reactor pressure vessels Vassilaros,M. G. et al. Nuclear Engineering and Design, 1998, 181, (l-3).
99l00416
Sulfur measurement In refined llqulds using sulfur 99ioo412 chemllumlnescence Haydt, D. D. Proc. Annu. ISA Analysis Div. Symp., 1998, 31, 79-88. A sulfur chemiluminescence analyser has been developed to measure sulfur in refined liquids. The analyser is designed to provide on-line, real-time measurement. It employs a plunger type liquid injection valve to deliver a small amount of sample to the chemiluminescence detection system. All sulfur bearing compounds are measured as a single peak representing total sulfur. The analysis technique is valid due to the inherent equimolar response of the detection system. Analysis ranges have been measured in a variety of backgrounds including gasoline, diesel, kerosene, naphtha, alcohols. and various solvents.
40
Fuel and Energy Abstracts
January 1999
61-69. In the beltline of reactor pressure vessels (RPV) the neutron embrittlement that occurs can be managed by various techniques, but only thermal annealing can reverse the effects and result in a restoration of RPV beltline material toughness. The US Nuclear Regulatory Commission has recently revised the Code of Federal Regulations to include the use of thermal annealing of RPV for recovery of material toughness. The Annealing Rule. 10 CFR Part 50.66, has an associated Regulatory Guide 1.162 that describes the format and content of a thermal anneal report that must be submitted to the NRC prior to performing an anneal. This paper will describe the thermal annealing process including regulatory requirements in 10 CFR Part 50.66, techniques for predicting and measuring the toughness recovery,