Cradle-to-Gate greenhouse gas emissions of the production of ethylene from U.S. Corn ethanol and comparison to fossil-derived ethylene production
Pahola Thathiana Benavides, Ulises R. Gracida-Alvarez, Kirti Richa, Jennifer Port, Troy R. Hawkins
Abstract
• Ethylene plays a crucial role as one of the most widely used platform chemicals in the industry. • Comparisons of bioethylene via corn ethanol dehydration and coprocessing via fluid catalytic cracking (FCC). • FCC ethanol to ethylene showed lower greenhouse gas (GHG) emissions than fossil-based ethylene production. • Evaluation of scenarios for low-carbon intensity ethanol production. Conventional ethylene production heavily depends on fossil-derived feedstocks via steam cracking, a very energy- and emission-intensive process. Researchers have been exploring alternatives to reduce CO 2 emissions including producing ethylene from biobased feedstocks. This paper evaluates the cradle-to-gate greenhouse gas (GHG) emissions of bioethylene produced from U.S. corn ethanol. The analysis includes different pathways for the dehydration of corn ethanol to ethylene and co-processing routes via fluid catalytic cracking (FCC) processes. For the FCC co-processing route carbon-14 analysis is used to determine bioethanol yields. A 127% reduction in life cycle GHG emissions of bioethylene is estimated compared to fossil-derived ethylene for the base case. Additional case studies are also discussed to understand the reduction of GHG emissions due to sustainable corn farming and renewable power use, biogenic carbon capture, and fuel switch with biofuels at the ethanol plant, and its impact on bioethylene GHG emissions.