Exelus Styrene Monomer Technology – ExSyM

Styrene monomer (SM) is a large volume commodity chemical used in the production of plastics and rubbers for numerous applications. It currently ranks fourth in production volume of monomers. 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.

The high energy usage of styrene processes directly results from the chemistry used. Conventional SM processes dehydrogenate ethylbenzene to generate styrene. It is an equilibrium-limited, endothermic reaction requiring temperatures in excess of 600°C. Large amounts of steam near 900°C are required to supply this heat. There is no way to significantly reduce the energy inputs to this type of a process.

ExSyM achieves up to 80% reduction in energy usage by changing the process chemistry, using instead the alkylation of toluene with methanol to form styrene directly. No dehydrogenation is required and the reaction is 50% less endothermic. The reaction also occurs at lower temperatures, near 400°C. Furthermore, the change in feedstocks reduces the production cost by about 35%. Researchers at Exelus have achieved yields in this reaction of 80%, making this route to styrene commercially viable for the first time.

New Chemistry
Process Benefits
Process Scheme and Performance