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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Low temperature Claus reactor studies

Besher, Elmarghani M. January 1990 (has links)
A small-scale fluidized bed reactor (0.1m ID, 0.86m high) was used to carry out the Claus reaction 2H₂S + SO₂ ⇌3/X Sx + 2H₂O at low temperatures (100 to 150°C) where elemental sulphur condensed on the catalyst particles (Kaiser alumina S-501, 195µm mean particle size). The experimental apparatus was similar to that described by Bonsu and Meisen (1985). The feed gas consisted of pure nitrogen mixed with H₂S and SO₂ in the ratio of 2 to 1. The H₂S concentration was varied from 200 to 1300 ppm. The feed gas flow rate ranged from approximately 1.4 to 5.6 m³/h. The corresponding U/Umf ranges were approximately 2.2 to 8.8. The bed heights varied from 0.12 to 0.38m. It was found that the experimental conversion efficiencies ranged from 60 to 96% and that they were less than those predicted thermodynamically. The conversion efficiency was found to increase with H₂S concentration and catalyst bed height; it decreased with gas flow rate. Contrary to thermodynamic predictions, the conversion efficiency increased with temperature. These results suggest that thermodynamic equilibrium was not achieved in the reactor. The decline in conversion due to catalyst fouling was measured as a function of catalyst sulphur content. The experimental results could be interpreted by means of a bubbling bed model. New analytical expressions for predicting the overall conversion and the concentration profiles were developed for reactions of order n. For the Claus reaction, where n=1.5, good agreement was found between the model predictions and experimental values. The model properly discribed the observed behavior resulting from changes in feed concentration, bed temperature, U/Umf and static bed height. The bubbling bed model was used to predict the effect of particle size on conversion for various operating gas velocities and bed dimensions. The model predictions showed that the canversion improved with decreasing particle size and that the improvement depended on U/Umf. The bubbling bed model was modified for conditions where condensed sulphur fouled the catalyst. A catalyst deactivation function, derived from first principles and based on catalyst sulphur content, was incorporated into the rate expression. The modified model predicted the the experimental measurements well and conclusions are drawn regarding the continuous operation of fluidized bed Claus reactor operating under sulphur condensing conditions. A general procedure is presented to demonstrate the applicability of the bubbling bed model in the design of large scale reactors; examples for specific conditions are given. Attrition tests were performed on the catalyst at U/Umf=5.1 and room temperatures. It was found that most of the attrition occurred in the first few hours when the catalyst particles were rough. The overall test results indicated that attrition of the catalyst was negligibly small thereby suggesting the suitability of the Kaiser S-501 catalyst for long term use in fluidized bed Claus reactors. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate
2

Desulphurization kinetics of molten iron by magnesium vapour

Irons, Gordon A. January 1978 (has links)
Note:
3

The study of a magnesium wire feeding technique for the desulphurization of molten iron and liquid steel /

Palumbo, Enzo A. January 1985 (has links)
No description available.
4

The study of a magnesium wire feeding technique for the desulphurization of molten iron and liquid steel /

Palumbo, Enzo A. January 1985 (has links)
No description available.
5

Magnetic enhancement in High Gradient Magnetic Separation

Kelland, D. R. January 1988 (has links)
No description available.
6

Nickelocene-lithium aluminum hydride : a new effective desulfurization reagent.

January 1986 (has links)
Cheng Kwok-man. / Bibliography: leaves 43-46 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1986
7

Reductive cleavage of the carbon-sulfur bond in bridged thiolato complexes.

January 1987 (has links)
Ngan-fong Ho. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 57-64.
8

Nickel (II) bromide bis-(triphenyl-phosphine)/lithium aluminum hydride: a versatile desulfurization reagent.

January 1988 (has links)
Kin Man Ho. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 61-65.
9

Tungsten hexacarbonyl mediated C-S bond cleavage reactions.

January 1988 (has links)
Ng Chi Tat. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 72-76.
10

Desulfur-dimerization of dithioacetals with tungsten hexacarbonyl: synthesis of bifluorenylidenes.

January 1987 (has links)
Yu Chi Yip. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 74-76.

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