Low Energy CO2 Capture Enabled by Biocatalyst Delivery System

Abstract

This work presents research and development progress to improve biocatalysts, solvents, and system integration to reduce the cost of CO2 capture from flue gas. Laboratory data and field demonstration illustrate the potential of biocatalyst-enhanced CO2 capture from coal generated flue gas using non-volatile alkali salt solutions. The first generation biocatalyst system (coated packing) demonstrated 6 to 7-fold enhancement in the volumetric average mass transfer coefficient at 40°C with 3460hours on coal flue gas with 80% CO2 capture on average. The first 2800hours operated with an aqueous solution of 20% K2CO3, and the final 660hours demonstrated a new higher capacity non-volatile alkaline salt solution (AKM24). Lessons learned from the first generation biocatalyst delivery system (coated packing) demonstration are summarized. A second generation biocatalyst delivery system (biocatalyst microparticles) is introduced that shows a greater potential for rate enhancement in laboratory tests. This new biocatalyst system also provides a lower cost method of biocatalyst addition and replacement on-stream. Preliminary modeling estimates show a total equivalent work less than 220 kWh/t CO2 (including CO2 compression to 150bar) in two possible process configurations. Preliminary cost analysis demonstrates potential for more than 30% reduction in CO2 capture costs relative to NETL Case 12, version 2 (30% MEA with 75 psig cross over steam, bituminous coal power plant).