The Reaction Engineering of Green Gasoline

Prof. de Lasa’s CREC group at the University of Western Ontario has been leading efforts to establish the reaction engineering of “green gasoline”. The main goal has been to determine how the FCC operating conditions influence benzene formation contained in gasoline. Benzene is a well-known cancerogenic and has to be minimized or avoided if at all possible. With these facts in mind, de Lasa invented, in 1992, a CREC Riser Simulator. The CREC Riser Simulator unit is currently commercialized by Recat Technologies (http://www.recattechnologies.com/). The CREC Riser Simulator has been used extensively in universities in Canada, Argentina, Mexico, Spain, Saudi Arabia, as well by several industrial companies around the world. The CREC Riser Simulator is a relatively simple, well-mixed device which enables reacting chemical species to come in contact with a fluidized catalyst throughout a predetermined time span of a few seconds. The CREC Riser Simulator is a constant volume reactor which uses a set amount of catalyst and fluid and operates isothermally. This reactor closely mimics the large scale FCC unit operating conditions matching partial pressures, reaction times, temperature and catalyst/oil ratio. This ensures that kinetic parameters are determined under relevant catalytic cracking conditions. Studies developed by de Lasa’s group have involved typical FCC catalysts having similar acidities, structural properties and different crystallite sizes: CAT-SC (0.4 m) and CAT-LC (0.9 m). Catalysts have been studied by contacting them with a number of model compounds such as 1,3,5-triisopropylbenzene and methyl-cyclohexane. This research has been valuable to establish a comprehensive heterogeneous kinetic model, to assess intrinsic kinetic constants and adsorption and diffusional parameters. The analysis of 1,3,5-triisopropylbenzene conversions and product distribution has helped to show the strong influence of intra-crystallite diffusional constraints on benzene yields.