In petrochemical refining operations the heavy petroleum fractions are fed to thermal cracking, catalytic cracking, or hydrocracking processes to convert higher molecular weight fractions into more valuable lighter molecular weight products such as gasoline. There processes produce a C4 (four carbon chain molecules) by-product stream. From this stream only a small proportion of the butenes (butadiene, isobutene) are removed and subsequently processed while the remaining C4 by-products are flared or used as low quality additives. Thus there is a need for a cost efficient way to convert these low value C4 streams to higher value products, such as additives to raise the octane rating for gasoline for example.
Description of the invention
Reactive distillation (RD) processes offer a number of advantages over traditional reactor/distillation systems including reduced capital costs, lower energy consumption, improved reaction rates, and higher selectivity. By distilling and removing the products from the reactants in the reaction zone, RD alters the reaction equilibrium barrier and allows higher conversion and selectivity. Internationally recognized catalysis researchers at Waterloo have developed a novel RD process to convert lower value alkenes (C2-C6) into higher value (C8-C12) alkenes. These higher molecular weight products are important industrial feedstock in the production of motor fuels, plasticizers, pharmaceuticals, dyes, resins, detergents, and fuel additives. Waterloo’s invention involves directly depositing the catalyst on the support structures made of inorganic oxides (alumina, silica, titania, zirconia) which are loaded directly into the column. This process bypasses the need for secondary catalyst support structures typically associated with traditional RD processes, which enhances the reaction kinetics and the ongoing separation of the reaction products and thus is much more efficient.
For example, the conversion of 1-butene to higher octane products:
- Higher conversion of C4 compared to batch and flow reactors (88% RD vs. 72% and 30%, respectively)
- Higher reaction selectivity compared to batch and flow reactors (87% RD vs. 64% and 78%, respectively)
- Reduced capital costs. Only one unit is required, and this can be a retrofitted distillation column
- C8-C12 alkenes feedstocks
- Aldol condensation
- One step synthesis of methyl isobutyl ketone from acetone
- Biomass conversion (e.g. 1,2- propane diol and 1,3- propane)