Integration of Biomass Gasification-Based Olefins Production in a Steam Cracker Plant—Global GHG Emission Balances

Artikel i vetenskaplig tidskrift, 2015

This paper investigates two options for integration of biomass-based olefin production with a fossil-based steam cracker plant at the heart of a chemical cluster. The work was conducted in the form of a case study considering the possible future partial replacement of a fraction of the cracker olefins with approx. 220 kt/y of biomass-based olefins (ethylene, propylene, and butylene) (approx. 25 % of total capacity) produced via gasification, methanol synthesis, and the methanol-to-olefins (MTO) process. Two options were compared with base case operation with fossil-only feedstock: (i) purchase of methanol produced off-site, and (ii) on-site methanol production. In both cases, the MTO section was assumed to be located at the cracker site, making use of existing olefin separation equipment. Consequences of such partial feedstock substitution for the steam, fuel gas, and electric power balances of the cracker plant were investigated. Potentials for generation of steam and electric power were estimated by assuming integration with a heat recovery steam cycle. Greenhouse gas (GHG) emission balances of the proposed options were estimated by applying a system boundary expansion approach. The GHG emission reduction potentials are shown to be between 50 % and 70 %, compared with the base case. The reduction potential depends on the choice of reference grid electricity generation technology but the major contribution comes from the introduction of renewable feedstock.