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.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xv, 155 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 120-123).

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / One of the very promising synthetic fuel production strategies is the Fischer-Tropsch process, founded on the Fischer-Tropsch Synthesis, which owes its discovery to the namesake researchers Franz Fischer and Hans Tropsch. The Fischer-Tropsch Synthesis (FTS) converts via complex polymerisation reaction a mixture of CO and H2 over transition metal catalysts to a complex mixture of hydrocarbons and oxygen containing compounds with water as major by-product. The mixture of CO and H2 (termed syngas) may be obtained by partial oxidation of carbon containing base feedstocks such as coal, biomass or natural gas via gasification or reforming. The Fischer-Tropsch (FT) process thus presents the opportunity to convert carbon containing feedstocks to liquid fuels, chemicals or hydrocarbon waxes, which makes, for instance, the monetisation of stranded gas or associated gas a possibility. The FT-process is typically carried out in two modes of operation: low temperature Fischer-Tropsch (LTFT) and high temperature Fischer-Tropsch (HTFT). LTFT is normally operated at temperatures of 200 – 250 °C and pressures of 10 – 45 bar to target production of high molecular weight hydrocarbons, while HTFT is operated at 300 – 350 °C and 25 bar to target gasoline production. The catalytically active metals currently used commercially are iron and cobalt, since product selectivity over nickel is almost exclusively to methane and ruthenium is highly expensive in addition to requiring very high pressures to perform optimally. Fe is much cheaper, but tends to deactivate more rapidly than Co due to oxidation in the presence of high H2O partial pressures. One of the major drawbacks to using Fe as FT catalyst is the requirement of lower per pass conversion which necessitates tail gas recycle to extend catalyst life and attain acceptable overall conversions. A more active or similarly active but more stable Fe-catalyst would thus be advantageous. For this reason promotion of a self-prepared typical LTFT Fe-catalyst with Ru was investigated. A precipitated K-promoted Fe-catalyst was prepared by combination of co-precipitation and incipient wetness impregnation and a ruthenium containing catalyst prepared from this by impregnation with Ru3(CO)12. The catalysts, which had a target composition of 100 Fe/30 Al2O3/5 K and 100 Fe/30 Al2O3/5 K/3 Ru, were characterised using XRD, SEMEDX, ICP-OES, TPR and BET N2-physisorption, before testing at LTFT conditions of 250 °C and 20 bar in a continuously stirred slurry phase reactor.

M.Phil. (Energy Studies) / South Africa has no commercially proven indigenous crude oil deposits. The country therefore follows a well formulated longterm energy policy to ensure a continuous and uninterrupted supply of transport fuels. The development of a very successful synfuel industry contributes to the national desire of maintaining a minimum level of self sufficiency in transport fuels. The Government also plays a supportive role in financing synthetic fuel projects from the Central Energy Fund. South Africa has abundant coal resources at a reasonable cost, as well as the offshore gas field near the coast of Mosselbay. The objective of this study is therefore to evaluate and compare the re1athe economics of certain direct and indirect coal liquefaction process routes, as well as the conversion of natural gas to transport fuels. The methanol option as a transport fuel is also addressed. Information for this study was collected mainly from the literature on this subject as well as Government institutions and private companies that are actively involved in the production of synthetic transport fuels. The primary conclusions of this study are: Synthetic fuel projects are capital intensive. The number of commercially proven options for the production of synfuels are limited to the well proven technology of the Sasol process, conventional methanol synthesis technology and to a lessor extent the Mobil methanol-to-gasoline technology. Accurate costs comparisons will therefore only be possible when more of the direct liquefaction options have been commercially demonstrated. Commercial realisat ion of the unproven technologies also involve enormous financial resources and a high risk. The Sasol synfuel option with the lowest thermal efficiency of approximately 42% requires the highest capital investment per ton or barrel of final product. The high severity direct processes (H-coal, Exxon-Donor-Solvent or EDS and the German Technology) as well as the Mobil-MTG capital investment follows, with the low severity and high thermal efficiency SRC-1 and SRC-2 process capital requirements the lowest, except for the very low,capital investment for a methanol synthesis plant...

Pillared clays present interesting possibilities for use as acid catalysts. The present research investigated the effect that pillaring has on the physical and catalytic properties of some smectite clays. The effect of using a hydroxy-Al solution to pillar a predominantly octahedrally ,substituted clay (montmorillonite) and a tetrahedrally substituted clay (beidellite) were compared. The effects of pillaring tetrahedrally substituted clays with different swellable properties (beidellite, SMM, and Ni-SMM) were investigated. In an attempt to enhance the acidic properties of the pillars, montmorillonite was pillared with a hydroxy-Al solution containing tetraethyl orthosilicate. Montmorillonite was also pillared with a hydroxy-Ni/Al solution in an effort to produce a clay with an increased pillar density. The pillared and unpillared clays were characterised using x-ray diffraction, surface area measurements, thermogravimetric analysis and ammonia TPD. The possible shape selective properties of the different clays for the conversion of trimethylbenzene were investigated, and the catalytic activities and product selectivities of these clays for high pressure propene oligomerisation were studied.

This dissertation reports the findings of an investigation aiming to the incorporation of the transition elements: cobalt, vanadium, and molybdenum into AlPO₄-5 molecular sieves, to the study of the redox properties of the resulting materials and to the potential application of these compounds in the partial oxidation of methane to methanol and formaldehyde. AlPO₄-5 molecular sieves containing Co, V, and Mo were synthesized by hydrothermal crystallization of typical aluminophosphate gels with the adequate metal substrates at temperatures of 200°C, 150°C, and 150°C respectively. Samples of each material were calcined in oxidant, reducing and inert atmospheres and the properties of the treated solids studied by different characterization techniques. The significant feature of the Co and V containing AlPO₄-5, CoAPO-5 and VAPO-5, is that they exhibit different colors depending on the treatment atmosphere. Evidence for cobalt contained in framework positions of CoAPO-5 is obtained by the change in its unit cell volume relative to AlPO₄-5, and by diffuse reflectance spectroscopy. CoAPO-5 also contains an appreciable quantity of extra-framework cobalt occluded in the pores, and/or as balancing cations. Evidence for this was obtained from ion exchange, and from oxygen and argon adsorption. Pentavalent vanadium incorporation is inferred from the change in the unit cell volume of VAPO-5 relative to AlPO₄-5, from pH measurements of the reaction vessel contents before and after heating, from oxygen and argon adsorption, chemical analysis, SEM, XPS, NMR, and diffuse reflectance spectroscopy. A scheme for the substitution of V into AlPO₄-5 is postulated based on the acidity observed in VAPO-5 by ion exchange, and potentiometrlc titration. Only a very small amount of Mo was found in the molybdenum containing AlPO₄-5. Evidence for Mo incorporation into the framework was not obtained. The use of CoAPO-5 and VAPO-5 as redox catalysts for the partial oxidation of methane to methanol and formaldehyde lead mostly to oxides of carbon. / Ph. D.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Microfiche copy available in Archives and Engineering. / Includes bibliographical references. / by Julian A. LoRusso. / M.S.

"This work was supported by the Center for Energy Policy Research of the M.I.T. Energy Laboratory."

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 198-215). Also available on the Internet.