M.Sc Thesis

M.Sc StudentLiron Ofir
SubjectTesting and Analysis of Propane Dehydrogenation in a Pd
Membrane Reactor
DepartmentDepartment of Chemical Engineering
Supervisor PROFESSOR EMERITUS Moshe Sheintuch
Full Thesis textFull thesis text - English Version


This work presents an analysis of the propane dehydrogenation (PDH) reaction, a method of reacting propane and hydrogen to produce propylene - an important pre-product in many industries. Propylene nowadays is mostly produced as a by-product of oil refining. Producing it from propane - which is present in natural gas - enables natural gas to be alternative propylene production source, increases propylene availability and decreases environmental impact associated with oil refining.

Traditional industrial PDH systems commonly consist of catalytic equilibrium reactors. As such, they suffer from equilibrium limitations and very fast catalyst deactivation - both are disadvantages which make the process industrially unattractive. The analysis presented here examines PDH on a novel, highly active Pt-Sn/Mg(Al)O catalyst while utilizing Pd membrane technology for selective hydrogen separation, both can potentially counteract the current process disadvantages by offering better activity and higher conversion. Addition of steam at the feed was also tested as a countermeasure to catalyst deactivation.

The goal of this work is to analyze the membrane integrated PDH system in aspects of kinetics, deactivation and diffusion effects and reactor design configuration in order to provide a comprehensive modeling of the system, enabling deduction of operating conditions and design which will improve the existing process and overcome its limitations.

A range of operating conditions for the PDH reaction system was experimentally tested. A comprehensive kinetic model for propane dehydrogenation on a Pt-Sn/Mg(Al)O catalyst was composed, with parameters estimated from experimental results. The model accounts for product distribution due to the main and side reactions and for effects of catalyst pellet diffusion. Deactivation models are also presented for the catalyst and the Pd membrane.

In order to examine the feasibility of the catalyst and membrane technologies in counteracting the traditional process disadvantages, two approaches for designing the system were modeled and analyzed: the integrated approach, consisting of a packed bed membrane reactor, and the distributed approach, consisting of a train of units consisted of an equilibrium reactor followed by a membrane separator.