(346c) Evaluation of Environmental Tradeoffs of Producing Renewable Jet Fuel and Polyisoprene from Biomass

Polyisoprene is a commercially valuable material that is used in the manufacture of more than 40,000 products. The two main resources used for its production are natural rubber trees and petroleum. This study examines the environmental performance of a new bioconversion method for producing polyisoprene from biomass and compares it to the two main alternative production routes. In this process, following pretreatment and hydrolysis, which release the fermentable sugars in biomass, we convert them to methyl butenol, which is further converted to isoprene in a dehydrogenation reactor and then polymerized into polyisoprene. In the same process, methyl butenol can be co-converted to dimethyl cyclooctadiene, a high-density jet fuel blend, in a dimerization reactor.

We develop a life cycle assessment (LCA) model based on experiments and chemical process simulations formulated with experimental measurement. To generate mass and energy balances required for the LCA, the energy and chemical input requirements for process stages are calculated using Aspen PLUS and Aspen HYSYS simulations, along with stoichiometry, thermodynamics, and kinematics equations.

The metrics studied are land use intensity as measured in land occupation per kg of polyisoprene produced and the 100-year global warming potential (GWP100), as a measure of climate change, measured in kg CO₂ equivalent per kg of polyisoprene. We found that the GWP of polyisoprene produced from both corn stover and forest residue is negative while that produced from petroleum and natural rubber tree is in the range of 0.5 to 15.9 kg CO₂/kg isoprene. Also, while the land use intensity of biomass-based polyisoprene is higher than that of petroleum, which is very close to 0, it is much lower than the land use intensity of natural rubber based polyisoprene.