A study of catalytic reforming.

Abstract

This thesis describes the design, construction and operation of a small pilot plant scale reforming unit using industrial reforming catalysts. Two reactors were used; a tubular packed bed reactor and a spinning basket gas/solid reactor. The range of process conditions in the packed bed reactor was; temperature 300-550 °C, pressure 16-36 bar abs., overall space velocity 0.1-3 vol. liq./hr./vol.cat., hydrogen/hydrocarbon ratio 3-12. The feed hydrocarbon was a C5-naphtha dosed with methylcyclopentane. Axial concentration and temperature profiles were measured in the catalyst bed. In general, the concentration profiles showed rapid initial conversion of methylcyclopentane to benzene and the C6-paraffins. In many cases these profiles reached maxima in the bed before declining as cracking to light products became significant. Data uninfluenced by diffusional limitations was used to compare power function and Hougen-Watson type reaction models. For the methylcyclopentane/benzene reaction the following Hougen-Watson type model is proposed, based on desorption of cyclohexene from the acidic catalyst function as the rate controlling step. The spinning basket reactor experiments (using a methylcyclopentane/hydrogen feed) were carried out in the operating ranges; temperature 300-470 °C, pressure 18-37 bar abs., space velocity 0.1-1.2 vol. liq./hr./vol.cat., hydrogen/hydrocarbon ratio 115-270. Catalyst studies included a bimetallic platinum/rhenium reforming catalyst which was shown to be more active at lower temperature and more selective with respect to benzene production. Kinetic models were studied based on the assumption that the spinning basket could be treated as a continuous stirred tank reactor. This modelling technique was unsuccessful due to lack of stability during mathematical analysis.

Date of Award	1978
Original language	English
Awarding Institution	University of Bath