Grant: Collaborative Research and Development Grants

About 1 million barrels per day (bpd) of oil equivalent is currently produced from Canada's oilsands and this is expected to reach 3 million bpd by 2020. Oilsands consist of bitumen, sand and water. The bitumen is separated from the sand and water before being upgraded to a synthetic crude oil. Upgrading the bitumen by coking yields liquid products that must be treated over a catalyst in the presence of hydrogen to remove S, N and other contaminants. The naphtha fraction of the liquid product, with boiling point < 177C, also contains significant quantities of olefins and diolefins that are stabilized by a low temperature (< 250C) catalytic hydrogenation before S and N removal. Although highly reactive, diolefins can be difficult to saturate and may undergo a polymerization reaction that results in carbon deposition on the catalyst. This leads to a rapid build-up of pressure drop in the reactor that ultimately results in early shut-down of the unit. The present proposal seeks to address the issue of catalyst fouling and deactivation in naphtha hydrotreaters by developing a better fundamental understanding of the catalytic and non-catalytic reactions occurring in the reactors. Initially, the study will focus on developing appropriate analytical methods to identify the onset of olefin and diolefin polymerization and polymeric carbon deposition on the catalysts. The rate of polymerization during both catalytic and non-catalytic reactions will be compared. Subsequently the effect of the reaction temperature and olefin concentration on the reactions will be examined. The reactivity of model olefins, diolefins and cyclic-diolefins will be determined so as to identify the key fouling components present in the naphtha. Finally the importance of various catalyst physical and chemical properties on the hydrogenation and polymerization reactions will be quantified. The goal of the study is to identify the process conditions and catalyst properties that reduce the rate of catalyst fouling in naptha hydrotreaters. Results from the study will aid in improving commercial reactor operability and contribute to the development of the next generation catalysts that aim to expand the operating window of naphtha hydrotreaters.