WASHINGTON UNIVERSITY

THE HENRY EDWIN SEVER GRADUATE SCHOOL DEPARTMENT OF CHEMICAL ENGINEERING

ABSTRACT

PHASE DISTRIBUTION AND PERFORMANCE STUDIES OF GAS-LIQUID MONOLITH REACTOR by

Shaibal Roy

Advisor: Professor Muthanna H. Al-Dahhan

May 2006

St. Louis, Missouri, USA

The present study looks into the viability of using a catalytic monolith multiphase reactor for solid catalyzed gas-liquid reactions in place of other conventional reactors. As part of this research, the important aspects of two-phase flow monolith reactors were studied, which include (a) investigation of the effect of reactor geometry and flow conditions on distribution of gas-liquid phase inside the monolith using γ-ray computed tomography, (b) integration of hydrodynamic and kinetics to determine the effect of flow reactor conditions on the overall performance of a monolith reactor, and (c) the development of a monolith scale model to evaluate the effect of flow and transport parameters on the monolith reactor performance.

Under several flow conditions, phase maldistribution was observed, which may prevent the monolith from reaching the desired output. Within the flow range studied, a window of operating conditions was identified within which the phases were nearly uniformly distributed. The effect of gas and liquid physical properties and the geometrical properties of the monolith on the phase distribution characteristics were also evaluated at selected conditions. Various liquid saturation correlations from the literature were evaluated for their validity to express liquid saturation in monoliths.

The effect of various operating and design parameters on the overall performance was investigated in a newly developed pilot scale monolith reactor (length: 0.45 m, diameter: 0.05 m) setup, which was designed and developed as part of this study. For comparison with monolith reactor performance, experiments were also performed to evaluate the performance of the extrudate catalyst in a trickle bed reactor at selected conditions. The productivity of the monolith reactor based on the active catalyst weight basis was found to be much higher compared to trickle bed reactor at all conditions.

Finally, a reactor scale model, that integrates the hydrodynamics and kinetics, was developed to predict the performance of the monolith reactor. The previously developed single tube model was extended to account for the flow non-uniformity in the monolith reactor bed. The developed model correctly captured the experimental trend of monolith reactor performance. The degree of non-uniformity was expressed in terms of a phase distribution effectiveness factor.