Development of New Generation Catalyst for the Isomerization of Lighter Alkanes

Abstract

Motor gasoline, which is used in Spark ignition engine, is a multicomponent mixture of various hydrocarbons. These hydrocarbons have different combustion characteristics. To produce a high quality gasoline molecular management is the present day concept of the refining industry. Fuel specifications for gasoline are becoming very stringent over the years. To meet these specifications new processes are emerging at the refinery horizon. In this context Bharat Stage-V gasoline, which would be required in Indian market in near future has to meet tight specifications in terms of Sulphur, octane number and olefin contents. The final gasoline which is produce in refineries is a blending component coming from various processes namely hydrocracking, thermal cracking, FCC, reforming, alkylation and isomerization. Out of these processes, isomerization of light naphtha into high-octane naphtha is a great relevance. Thus, isomerization of n-alkane into high-octane number di- branched alkanes is an important challenge for petroleum refining industries. Thermodynamically lower temperature is favored for the isomerization of light alkanes into di-branched isomers. The conventional commercial catalyst namely chlorinated Pt/Al2O3 works at low temperature but it is easily poisoned and not ecofriendly. In addition, of Pt/Al2O3 many isomerization catalysts such as Pt/zeolite Pt/sulphated zirconia and others have been developed and used in recent past. But these catalyst have certain drawbacks like resistence to water, and Sulphur in feed, and they are non-regenerable, secondely these catalyst worked at high temperature resulting low isomerate yield. Thus, the development of isomerization catalyst to replace the conventional catalyst is an area of research worth exploring and occupied mind of researcher world over. The present work is an effort to developed HPA based sulphated zirconia catalyst effectively promoting firstly hydrogenation /dehydrogenation function and protonic acid function. Thus, heteropoly acids supported on oxidic material was chosen as an appropriate material for the isomerization reaction. Oxidic support could provide the dehydrogenation activity and heteropoly acid could support protonation activity.