京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20580号 / 工博第4360号 / 新制||工||1678(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 安部 武志, 教授 阿部 竜, 教授 作花 哲夫 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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The water quality characteristics of a coal slurry were found to vary widely, depending upon the coal used and the use of a corrosion inhibitor. The coal-water interactions were evaluated in a pilot-plant closed-loop coal slurry pipeline. Pulverized coal from eastern Kentucky and tap water were slurred and pumped through a 40 foot (12.2 m) pipe loop for ten days. Slurry samples were collected at 3 hours, 7 hours, 1 day, 2 days, 4 days, 7 days and 10 days from the start of a run. The samples were filtered and analyzed for 29 water quality parameters, including 15 metals. Two runs were performed without adding a corrosion inhibitor and two runs were performed with the addition of a corrosion inhibitor. The coal slurry filtrate contained high levels of sulfates, total dissolved solids, conductivity, acidity, iron, magnesium, manganese, lead and aluminum. The pH dropped initially, depending upon the percent sulfur in the dry coal and the alkalinity in the slurry, but returned to 6-7 after 10 days in the pipeline. Metal concentrations were a function of the pH, which affected solubility. Organics in the filtrate were at low levels. The addition of a corrosion inhibitor increased the concentrations of most parameters.

A complete wastewater characterization study was performed on an eastern Kentucky coal slurry after a 10-day circulation period in a 40 foot (12.2 m) pilot-scale pipeline. The resulting wastewater was settled and decanted for additional lime and alum treatability studies. Easter coal slurries were characterized by high TDS, conductivity, sulfates and iron. Significant concentrations of a number of trace metals were also found; however, organics were very low. Wastewater quality varied considerably among several experiments and was presumed to be influenced by different properties of the coal and the addition of a corrosion inhibitor. The major treatment concern was removal of high concentrations of iron, manganese, and trace metals if wastewaters were to be discharged. Lime treatment was found to effectively remove iron, magnesium, manganese and many other trace metals from coal slurry wastewaters. Alum treatment methods were considerably less effective for metals removal; however, alum was more effective in removing organics, color and turbidity. The addition of a corrosion inhibitor was found to reduce treatment removals for both lime and alum treatment. Several alternative uses were proposed for slurry wastewaters based on predicted water quality and volumes.

Pretreatment of Pittsburg seam B coals to decrease its ash content and increase its solvent extractable material was investigated by anodically electrolysing acidified coal-water slurries at potentials around 1.0V SCE. The effects of the pretreatment were examined as functions of coal particle size, acid strength of the slurry, time of electrolysis and applied potential. The coal electrolysis was found to be most efficient at low acid strengths and short electrolysis times. The morphology of the coal surface changed with the conditions of the electrolysis and related to the percentage ash removal and the amount of solvent extractable material present in the coal. The anodic oxidation of the coal is suspected to occur via an electrocatalytic(EC) mechanism, whereby ferrous ions in the coal are first oxidised at the anode to the ferric state. The ferric ions migrate into the coal and accept electrons from accessible bonds in the coal micelle thereby reducing themselves back to ferrous ions and return to the anode for re-oxidation to the ferric state. The acceptance of electrons from certain bonds in the coal micelle results in the break-up of the micelle in to simpler compounds. Accordingly, the solubility of the coal in an organic solvent should increase and this was found to be so when ferrous ions were externally added to the electrolyte. The electrolytic process was also found to transfer metallic ions present in the coal into solution in the electrolyte. / Master of Science

No / In this paper, hydrodesulfurization (HDS) of crude oil in the three-phase slurry reactor over cobalt – molybdenum catalyst (CoMo / ɣ- AL2O3) is studied. Effects of space velocity and length of reactor on the conversion rate and catalyst effectiveness for HDS process have been investigated. Kinetics of the reaction rate for this process is primarily and Arrhenius equation for the rate constant is used. The results show that the effectiveness factor for catalyst along the length of reactor is decreased about 83%. By increasing liquid velocity from 4 to 10 1/s, the conversion of sulfur components is decreased about 22% at the temperature of 523 K. At the same temperature, by increasing liquid velocity from 36 to 84 1/s conversion is reduced to 25%. The results of the variation of the dimensionless reaction rate against conversion show that with increasing conversion, the reaction rate decreases and the reaction is stopped when the conversion is 100%.

A formulation was developed for the rheological characterization of highly concentrated suspensions, accounting for the physical effects of particle size distribution. A number of dimensionless parameters were developed signifying the physical characteristics of the solids and the vehicle fluid, and functionally related to the yield-stress and a flow parameter. Each of these expressions of the formulation contains an empirical dimensionless coefficient accounting for the interparticle and fluid/solid interactions that are not explained by the physical parameters involved. A formulation and a methodology were also developed for predicting the shear viscosity behavior of highly concentrated suspensions at low and high shear-rates through the use of three parameters signifying effects of particle size distribution. A number of applications were made using various non-coal and limited coal-liquid mixture data reported in the literature to demonstrate the general validity of the formulations. A methodology was proposed for the analysis of the particle size distribution effects on the overall optimum energy efficiency during hydraulic transportation and particle size reduction. The computer model developed for this purpose was employed to evaluate the transportation energy consumption and the energy consumed in the grinding process to prepare the slurry, in pipes of various sizes and lengths for a coal slurry of various specified particle size distributions and concentrations. Correlations obtained indicated the sensitivity of transportation energy efficiency to various parameters including the maximum packing concentration, relative concentration, specific surface area of particles, surface area mean size, pipe size and length, and annual mixture throughput. The results of combined energy calculations have shown that the particle size distribution and related physical parameters can significantly affect the energy efficiency due to both grinding and transportation, and the delivered cost of slurry fuels. / Ph. D.