(127f) Step-out Technology for Styrene Monomer Production

Styrene monomer is a large volume commodity chemical used in the production of plastics and rubbers for numerous applications. Current global styrene demand is about 25 million metric tons per year. However, its production consumes tremendous amounts of energy ? about ten times the average of similar chemicals. Styrene production is also a major contributor to methane emissions.

Exelus has completely broken with the traditional route and aims to achieve significant savings by using alternative process chemistry. The new technology under development by Exelus side-steps this energy usage and the associated greenhouse gas production by forming styrene using alkylation of toluene with methanol. A route using toluene and methanol is attractive since both feedstocks are much less expensive than benzene and ethylene and has the benefit of forming styrene directly, creating a single-step process without the need for an energy-intensive dehydrogenation reaction. However, the process has never been commercialized due to the low yields of styrene produced. A side reaction, the decomposition of methanol to hydrogen and carbon monoxide, often consumes much of the methanol, leading to a low overall selectivity of methanol reacting to form styrene.

By combining elements of reaction engineering with advanced catalytic materials researchers at Exelus have developed a new multifunctional catalytic system that allows significantly higher yields of styrene (>78%) at complete methanol conversion at 400oC, 3 WHSV and 1 atm pressure. This was achieved through careful optimization of active sites, adsorption characteristics and a pore architecture that reduces pore-diffusion limitations. As a result, the new catalytic system is easily able to achieve a quantum jump in performance over conventional solid-base catalysts leading to product selectivity and reaction rates that are already within the range of commercial viability.

This new technology has the ability to slash energy costs by over 80% for a conventional styrene plant. In addition, this technology allows a significant cost-reduction potential for styrene producers. Finally, this new technology will be able to reduce this amount by a large percentage by significantly reducing the amount of natural gas required in the process. This new styrene technology is an effective example of a new paradigm in developing process technologies - it results in a win-win situation for both the petrochemical operators as well as for the environment by simultaneously reducing CO2 emissions while increasing profit margins significantly.