Main content area

Market-Driven Emissions from Recovery of Carbon Dioxide Gas

Supekar, Sarang D., Skerlos, Steven J.
Environmental Science & Technology 2014 v.48 no.24 pp. 14615-14623
activated carbon, attributional life cycle assessment, carbon dioxide, consequential life cycle assessment, coproducts, desiccants, distillation, global warming, greenhouse gas emissions, heat, manufacturing, temperature
This article uses a market-based allocation method in a consequential life cycle assessment (LCA) framework to estimate the environmental emissions created by recovering carbon dioxide (CO₂). We find that 1 ton of CO₂ recovered as a coproduct of chemicals manufacturing leads to additional greenhouse gas emissions of 147–210 kg CO₂ eq , while consuming 160–248 kWh of electricity, 254–480 MJ of heat, and 1836–4027 kg of water. The ranges depend on the initial and final purity of the CO₂, particularly because higher purity grades require additional processing steps such as distillation, as well as higher temperature and flow rate of regeneration as needed for activated carbon treatment and desiccant beds. Higher purity also reduces process efficiency due to increased yield losses from regeneration gas and distillation reflux. Mass- and revenue-based allocation methods used in attributional LCA estimate that recovering CO₂ leads to 19 and 11 times the global warming impact estimated from a market-based allocation used in consequential LCA.