Faculty Advisor

Moser, William R.

Abstract

The partial oxidation of methane to synthesis gas has been investigated over a number of Rh/Ni supported catalysts synthesized using hydrodynamic cavitation techniques. Both solid state theory and molecular dynamics predict that the rates of catalytic reactors should be greatly accelerated if the primary grain sizes of the catalysts are in the range of 1 to 15 nm. The objective of this research was to determine if the generation of cavitation during the synthesis of metal supported catalysts enabled the production of nanostructured metal particles, and to what extent Rh/Ni catalysts are active towards partial oxidation of methane reactions. Hydrodynamic cavitation was used to produce pure alloy catalysts consisting primarily of different loadings of nickel and rhodium on ZrO/AlO support. Cavitational effects were analyzed with a series of 1% Rh, 5% Ni catalysts on ZrO/AlO, of which the largest was 11 nm. Grain size was determined from XRD line broadening techniques. BET and UV Visible analyses were also used to characterize the catalysts. Two additional series of Rh/Ni on ZrO/AlO were designed to study the effect of total metal loading (0.75 to 12 wt%) and the effect of rhodium loading (0.01 to 2 wt%). The catalytic investigation of these catalysts in a key environmental application, the oxidation of CH to synthesis gas in oxygen resulted in some remarkable catalytic reactivities. The reactivity data on the series of 0.75 to 12 wt% metal catalysts revealed a systematic increase in the CH oxidation activity as well as the H and CO selectivities as the grain sizes decreased below 15 nm. This study verified the theoretically predicted acceleration of catalytic reactivity for catalysts if they can be synthesized in grain sizes between 5 and 15 nm. The data further concluded that hydrodynamic cavitation offers novel routes for the systematic preparation of active catalysts having variable grain sizes, although further work needs to be completed to perfect the design of the equipment employed for our syntheses. Finally, Rh/Ni catalysts were found to be very active towards the partial oxidation of methane to synthesis gas, with only slight problems due to carbon deposition and support phase transformation.

Publisher

Worcester Polytechnic Institute

Date Accepted

January 1999

Major

Chemical Engineering

Project Type

Major Qualifying Project

Accessibility

Restricted-WPI community only

Advisor Department

Chemical Engineering

Advisor Program

Chemical Engineering

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