Catalytic Transformation of Greenhouse Gases in a Membrane Reactor

Type of Document Dissertation
Author Prabhu, Anil K
Author's Email Address nexafs@yahoo.com
URN etd-03142003-171853
Title Catalytic Transformation of Greenhouse Gases in a Membrane Reactor
Degree PhD
Department Chemical Engineering
Advisory Committee
Advisor Name Title
S. Ted Oyama Committee Chair
Brain E. Hanson Committee Member
David F. Cox Committee Member
Eva Marand Committee Member
Richey M. Davis Committee Member
Keywords

* Mathematical Model
* Vycor Membrane
* Hydrogen Selective Nanosil Membrane
* Membrane Reactor
* Dry Reforming
* Nickel and Rhodium Catalysts

Date of Defense 2003-03-13
Availability unrestricted
Abstract

Supported Ni and Rh catalysts were developed for the reforming of two greenhouse gases, methane and carbon dioxide to syngas (a mixture of hydrogen and carbon monoxide). This is an endothermic, equilibrium limited reaction. To overcome the thermodynamic limitations, a commercially available porous membrane (Vycor glass) was used in a combined reactor-separator configuration. This was to selectively remove one or more of the products from the reaction chamber, and consequently shift the equilibrium to the right. However, the separation mechanism in this membrane involved Knudsen diffusion, which provided only partial separations. Consequently, there was some transport of reactants across the membrane and this led to only marginal improvements in performance. To overcome this limitation, a new membrane was developed by modifying the Vycor substrate by the chemical vapor deposition of a silica precursor. This new membrane, termed Nanosil, provided high selectivity to hydrogen at permeabilities comparable to the support material. Application of this membrane in the combined reactor-separator unit provided higher conversions than that obtained using the Vycor membrane.

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