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Gas cleaning is an essential step in many chemical processes. The reason for cleaning is to remove components that can damage equipment or inhibit further reactions. The treatment can include the removal of particulates, removal of one or more chemical species, or the conversion of one species to another. The gases include natural gases, combustion gases or synthesis gas (syngas). Of particular importance is the hot gas desulphurization (HGD) of syngas after gasification. This method of treatment offers potential energy and raw material savings to traditional ‘wet’ gas cleaning methods, such as physical or chemical absorption. Syngas is a valuable intermediate product because it can be processed into a number of different chemicals. These range from hydrocarbon chains (Fischer-Tropsch reactions), methanol, and ammonia (from hydrogen in the syngas). Methanol and ammonia are important raw materials to produce other chemicals. Syngas can be used for production of electricity via gas turbines in an Integrated Gasification Combined Cycle (IGCC) plant. In this study, a laboratory scale gasification and desulphurization unit was designed and constructed for removal of hydrogen sulphide (H2S) from syngas. The gasifier operates at moderately high temperature (700-900 °C) and low pressure (1-3 bar g) to produce syngas containing H2S (1-6 mol %) from a liquid hydrocarbon fuel mixture and oxygen. Desulphurization occurs in a fixed bed isothermal reactor (300-600 °C) whereby H2S is removed by chemical reaction with a sorbent. The fuel used was a mixture of methanol and ipropanethiol and the sorbent chosen was zinc oxide. The apparatus was tested to obtain a reliable experimental method. A series of experiments were conducted to determine two results: Firstly, to see the performance of the unit during repeated sorbent testing (i.e. a systematic experimental run programme). Secondly, to determine the effect of some process variables (temperature, flowrate and particle size) on the conversion of sorbent. GC analysis of the syngas showed consistent gas composition during the experiment, an important result which justifies this new method of syngas production from a liquid fuel. The final conversions from ZnO to ZnS ranged from 2-12 mole %. However, there was some variation under repeated conditions, which showed the need for additional method development. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

The purpose of this study is to determine sound principles for custodial service in the small school.

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Estágio realizado na UNICER Bebidas, S.A. e orientado pelo Eng.ª Maria-Manuel Dantas / Tese de mestrado integrado. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 2009

Tese de mestrado integrado. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 2010

Weyerhaeuser's Paper Mill in Albany, Oregon has been experiencing frequent ring formation in the #3 rotary lime kiln. Rings form when lime mud (CaCO₃) or product lime (CaO) particles adheres to the walls of the lime kiln and become resistant to the abrasive action of the sliding motion of product lime particles (Notidis, 1994). Ring formation has resulted in frequent shut downs to remove (blast) the rings and caused a significant loss of productivity and revenue to the company. A careful analysis of the production process in the mill revealed that concentration of sodium was high and that of sulfur low in the lime mud. The high sodium was due to the low sulfur input to the kiln resulting in high sodium to sulfur ratio. The use of natural gas as a fuel source in the kiln partly causes low sulfur levels in the mud. This study examines the effects of burning emulsified sulfur in the #3 rotary lime kiln to reduce sodium enrichment in the solids, and examine its effect on kiln operation and SO₂ emissions from the #3 rotary lime kiln. A four day trial of burning emulsified sulfur to reduce sodium concentration in the #3 rotary lime kiln was planned. Tote bins of 70% solution of emulsified sulfur was fed into the #3 rotary lime kiln. The sulfur feed was controlled to ensure an excess of sulfur by observing the SO₂ concentration in the kiln stack and maintaining a concentration above 100 ppm corrected to 10% oxygen. The results show that while burning emulsified sulfur had no significant effect on kiln operation, it resulted in a high reduction of sodium in the dust caught in the electrostatic precipitator and an increase SO₂ emission from the stack. The reduction of sodium in the dust was 50%, which is an enrichment factor of 2. Although lime can effectively remove SO₂, the removal efficiency decreased from 96.0% to 73.0% when emulsified sulfur was burned in the #3 rotary lime kiln. The results of this trial are promising, since it demonstrates that burning emulsified sulfur significantly lowers the sodium enrichment in the kiln. The reduced levels of sodium can potentially lead to a reduction in ring formation in the #3 rotary lime kiln in the Albany Paper Mill. / Graduation date: 2004