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APPLICATION OF CONDITIONAL SIMULATION MODEL TO RUN-OF-MINE COAL SAMPLING FREQUENCY DETERMINATION AND COAL QUALITY CONTROL AT THE POWER PLANT (BLENDING, GOAL PROGRAMMING, MICROCOMPUTER).BARUA, SUKHENDU LAL. January 1985 (has links)
Run-of-mine (ROM) coal sampling is one of the most important factors in determining the disposition of ROM coal for an overall emission control strategy. Determination of the amount of sample, or still better, the frequency of ROM coal sampling is thus essential to the analysis of overall emission control strategies. A simulation model of a portion of the Upper Freeport coal seam in western Pennsylvania was developed employing conditional simulation. On the simulated deposit, different mining methods were simulated to generate ROM coal data. ROM coal data was statistically analyzed to determine the sampling frequency. Two schemes were suggested: (1) the use of geostatistical techniques if there is spatial correlation in ROM coal quality, and (2) the use of classical statistics if the spatial correlation in ROM coal quality is not present. Conditions under which spatial correlation in ROM coal quality can be expected are also examined. To link the ROM coal and coals from other sources to coal stockpiles and subsequently to solve coal blending problems, where varying qualities of stockpiled coals are normally used, an interactive computer program was developed. Simple file-handling, for stockpiling problems, and multi-objective goal programming technique, for blending problems, provided their solutions. The computer program was made suitable for use on both minicomputer and microcomputer. Menu-driven and interactive capabilities give this program a high level of flexibility that is needed to analyze and solve stockpiling and blending problems at the power plant.
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Application of synthetic molecular sieve zeolites and silica gel towards the separation of sulfur dioxide from combustion gasesWright, George Todd January 1979 (has links)
An evaluation of several commercial adsorbents for use as contacting media in a process for combustion gas desulfurization was performed. Linde Synthetic Molecular Sieves types 13X and AW500 and Davison Silica Gel were the materials studied. The motivation for this investigation was based on the premise that a suitable method for removing sulfur dioxide from combustion gas streams has not been realized.
Sulfur dioxide adsorption capacities were obtained for equilibrium (non-flow) and dynamic flow conditions. Sulfur dioxide adsorption on the molecular sieves could be described by a modified Langmuir expression of the form
q/q<sub>m</sub> = kc<sup>1/n</sup>/ 1 + kc<sup>1/n</sup>
Calculated isosteric heats of adsorption were found to agree with measured data.
Small scale dynamic studies consisted of contacting the adsorbents in a packed column with a simulated combustion gas. Evaluation of the adsorbent materials consisted of monitoring the effluent gas concentration after exposure to a step change in sulfur dioxide concentration.
Sulfur dioxide loadings were greatest for the type 13X molecular sieve followed by AW500 molecular sieve. The effect of gas throughput was minimal which suggests that mass transfer was adsorbent side controlling. As gas temperature increased, sulfur dioxide adsorption decreased linearly for 100 percent sulfur dioxide concentration and non-linearly for low concentrations (0.003 percent).
The effect of water vapor on sulfur dioxide adsorption capacity was determined by monitoring the effluent gas composition for specified sulfur dioxide-water vapor mixtures. Breakthrough time for sulfur dioxide was found to be an inverse function of the inlet water vapor concentration. For a typical combustion gas stream, (8 percent water vapor) the breakthrough time is roughly 10 percent of the water vapor free value.
Based on the results obtained, a shallow bed (0.15m, 0.5 ft) of either type 13X or AW500 molecular sieve removed 5 to 3 times that of activated charcoal for a gas temperature of 57.2°C (135°F) and low gas pressure drop 4.6 cm H₂0 (1.85 in. H₂0).
Adsorption degradation studies were performed to determine the loss in sulfur dioxide adsorption capacity after adsorbent regeneration. Both the 13X and AW500 molecular sieve could be regenerated, but the loss in adsorption capacity depended on the gas contacting conditions. X-ray spectroscopy was used to determine the homogeneity of the sulfur distribution within the adsorbents. The sulfur dioxide adsorption capacity for subsequent regeneration cycles was found to be a function of the Al₂O₃/SiO₂ ratio of the molecular sieve.
Application of the molecular sieve adsorbents in a simulated combustion gas for sulfur dioxide removal was found to be superior to several adsorbents for the temperature range 21-76°C (70-170°F). However, as gas temperature increases, sulfur dioxide adsorption decreases. No adsorption of sulfur dioxide above 148°C (300°F) could be measured. / Ph. D.
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