Biomass gasification-based olefins production - Process design and modeling

The chemical industry sector is energy-intensive and currently heavily dependent on fossil feedstock. The most relevant option to reduce fossil feedstock dependence and greenhouse gas (GHG) emissions is to increasingly switch to renewable feedstock. One promising route to convert lignocellulosic biomass, such as forest residues, to value-added chemicals and materials is thermochemical gasification. This work presents the process design and process modeling results of a biomass-based olefins production process. The value chain investigated is thermochemical gasification of lignocellulosic biomass, gas cleaning and conditioning, followed by dimethyl ether (DME) synthesis, conversion to olefins, and upgrading. The DME-to-olefins (DTO) concept is very similar to the methanol-to-olefins (MTO) concept. Chang and Silvestri [1] found the only difference between the two concepts to be the methanol dehydration, without effect on the hydrocarbon distribution. Accordingly, the difference basically lies within the choice of intermediate chemical and associated syngas conditioning and synthesis. Mass and energy balances for the biomass-based olefins process were obtained using process simulation models. The modeling results were validated by comparing with information reported in the literature. The results from this study is to be used as input for a process integration study, conducted as a case study, involving an naphtha steam cracker plant at the core of a chemical cluster in Sweden that supplies neighboring sites with light olefins