Summary:In the present work, using the catalysts used in the long run activity tests, the deposits of the carbonaceous materials, vanadium and nickel on the catalyst beds or on the surface of the catalyst particles was investigated. From the experimental results, the following conclusions were obtained.(1) In the early stage of the formation of the deposits, the amount of deposits was dependent on the temperature distribution inside the reactor. However, with the progress of reaction time, the amount was apt to increase more in the lower part of the catalyst bed rather than in the upper part. The average amount of the deposited carbon became constant after 100 hours on stream and the increase afterward was not recognised. The average amount varied with the kinds of the catalysts and the amount of asphaltene contained in the feed oil.(2) Though varied with the catalyst, vanadium deposited more in the upper part of the catalyst bed and less in the lower part. The activation energy of the vanadium was about 10kcal/mol. (3) Through nickel is similar in behavior to vanadium which tends to deposit more in the upper part and less in the lower part, it spreads out more widely on the whole catalyst bed.(4) On the catalysts of smaller mean pore diameter, the vanadium deposited in little amount, thinly but densely on the surface. While, on the catalysts of larger mean pore diameter, it deposited in large amount, but sparsely on the surface, and deeply as far as the considerably inner part. Nickel, like vanadium, deposited in much amount and spread to as far as the considerably deep inner part of the catalyst particles. Carbon deposited inside of cracks or holes which had been supposedly produced during preparation of the catalyst.
Summary:The catalysts used for the long run activity tests of hydrodesulfurization reaction of the residual fuel were regenerated by burning with air. Physical properties and the desulfurization activity of the regenerated catalysts were studied. From the experimental results, the following conclusions were obtained. 1) The specific surface area of the catalysts used for the long run activity tests decreased to 40 % of the original value of the fresh catalysts. The specific surface area after regeneration recovered up to 50% in the upper part of the catalyst bed and about 70% in the lower part. The specific surface area of the catalysts after about 100 hours on stream was almost completely regenerated. The pore volume also varied in proportion to the degree of recovery of the specific surface area. The mean pore diameter became greater than that of the fresh catalyst by regeneration.2) The pore size distribution varied remarkably during the 100 hours on stream from the start, and after which it maintained almost the same distribution. Pores were plugged up by the deposited carbon and metals on the surface of the catalyst. Sites of the plugged up pores were considered to be different with different catalysts. The pore size distribution recovered more at the upper part of the catalyst bed than at the lower part after regeneration. 3) When the decrease in the catalyst activity was caused by the deposited carbon, the major part of the activity was recovered after regeneration. However, when the decrease in the activity was due to the deposited metals like vanadium etc., the activity was not recovered, since the metals could not be removed by regeneration.
Synopsis:In order to study the phenomenological changes in the blast furnace accompanied with the injection of heavy oil at the tuyere, the reaction gas at the tip of the tuyere was sampled by, the use of the horizontal probe and analysed. In the case of no oil injection, CO2 content increased with decreasing oxygen content in the inward direction gradually, and after reaching the maximum point of CO2 content, CO and H2 content increased. When the injection rate of heavy oil increased, these phenomena tended to proceed rapidly and to be accomplished in shorter range. When the nozzle head of the oil burner was pulled backward in the blow pipe, the decrease of oxygen occurred even in the blow pipe. The decrease of the space of the raceway accompanied with the increase of oil rate was found also by the bar-test. The gas distribution at the top of the shaft was measured by the horizontally inserted probe installed at the stockline level and the gas efficiency was calculated.
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