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Chemical Engineering

LSU Master's Theses

Cerium oxide

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Desulfurization And Tar Removal From Gasifier Effluents Using Mixed Rare Earth Oxides, Sumana Adusumilli Jan 2010

Desulfurization And Tar Removal From Gasifier Effluents Using Mixed Rare Earth Oxides, Sumana Adusumilli

LSU Master's Theses

Biomass gasification is a promising source of fuels. However, hydrogen sulphide, tars and other by-products must be removed from the raw gas because they deactivate downstream reforming and water gas shift catalysts. The goal of this project is to find the best REO combination for simultaneous tar cracking and desulfurization of gasifier effluents and to find the sorbents that are stable at high operating temperatures of gasifiers. Simultaneous tar cracking and H2S removal from a simulated gasifier effluent was tested using different rare earth mixed oxide (REO) catalysts/sorbents based on Ce/LaOx, Ce/La/MOx and Ce/La/M2Ox/Al2O3 where M is a transition metal …


Sulphur Removal Using Regenerable Sorbents Of Rare Earth/Transition Metal Oxides, Vikram Reddy Kalakota Jan 2008

Sulphur Removal Using Regenerable Sorbents Of Rare Earth/Transition Metal Oxides, Vikram Reddy Kalakota

LSU Master's Theses

Hot gas desulfurization of gases from primary gasifier can be accomplished using sorbents composed Zn, calcium and transition metal oxide sorbents. The problem with metal oxide sorbents alone is that they are easily reduced at high temperature above 873 K to metallic state under reducing atmosphere decreasing their desulfurization capacity. Sorbents studied for hot gas desulfurization were based on Ce/La/M (M = transition metal) oxides and Ce/La/RE (RE = a rare earth) oxide. Sorbents were prepared using sol-gel method and the rare earth oxides were doped with transition metals using incipient wetness impregnation. Sulfidation experiments were carried out at 873 …


Zeolite And Metal Oxide Catalysts For The Production Of Dimethyl Sulfide And Methanethiol, Craig Plaisance Jan 2005

Zeolite And Metal Oxide Catalysts For The Production Of Dimethyl Sulfide And Methanethiol, Craig Plaisance

LSU Master's Theses

Metal oxide and zeolite catalysts were examined to determine their suitability for the production of methanethiol and dimethyl sulfide from the condensation of methanol and hydrogen sulfide. Fixed bed reactor experiments were used to test the catalysts in these processes. The acid sites of these catalysts were characterized by investigating the thermal desorption of 1-propanamine from these sites. It was found that WO3/ZrO2, La2O3/Al2O3, g-Al2O3, and HZSM-5 catalysts were active and selective in the production of dimethyl sulfide. On these four catalysts, the reaction converting methanol to dimethyl ether and the methanethiol disproportionation reaction were fast and close to equilibrium. …