Life cycle and techno-economic assessment of ethyl lactate production via reactive distillation with structured catalytic packing

A novel ZSM-5@SiC structured catalytic packing (ZSM-5@SiC SCP) was recently proposed to combine catalysis and separation functionality in one unit for reactive distillation (RD) towards the synthesis of green solvent ethyl lactate (EL). This work conducts life cycle assessment (LCA) and economic analysis for the RD process to identify relevant hot spots and suggest further development. Based on the cradle-to-gate LCA, the major environmental hot spots of the proposed RD process based on SCP are identified as in the section of raw materials extraction and RD. Compared to the petrochemical counterparts, bio-derived lactic acid and ethanol show the advantage to reduce carbon emission and resource depletion, but having significant impacts on aggravate stratospheric ozone depletion and land use especially. LCA results also show that preparation ZSM-5@SiC SCP creates environmental impacts due to the usage of electricity and relevant raw materials. Comparative LCA and economic analysis were conducted for the RD processes using ZSM-5@SiC SCP and seepage catalytic packing internal (SCPI), respectively, and a conventional process with separated reaction and separation unit operations. The findings suggest that compared to the conventional process RD processes can reduce greenhouse gas emissions and total annual cost (TAC) due to process intensification. The process employing ZSM-5@SiC SCP incurs a higher TAC than that based on SCPI (with resin catalysts), which is due to its comparatively low catalytic activity, requiring more ZSM-5@SiC SCP and higher column to achieve the production target.