서강대학교

초록

Transforming synthesis gas (syngas) or industrial waste gas including carbon monoxide (CO) into useful organic compounds has recently attracted attention. However, the major limitation associated with CO utilizing industry is the gas-to-liquid mass transfer limitation of CO. In this study, various Zeolite-A-coated perforated baffles were employed to enhance the volumetric mass transfer coefficient (KLa) in an external loop airlift reactor. Contact angle measurements reveal that Zeolite-A is much more hydrophilic than bare stainless steel, contributing to the formation of smaller gas bubble and higher KLa. The effect of the configuration of the perforated baffle, i.e. hole diameter, free area ratio, and the number of the perforated baffles, was also investigated. CO to formate fermentation using CO dehydrogenase (CODH) and formate dehydrogenase (FDH) was conducted in the airlift reactor with a Zeolite-A-coated perforated baffle under various gas flow rates. KLa value increased by 65.5 % from 78.2 to 129.4 hr-1 and maximum formate productivity increased by 71.6 % from 35.19 to 60.39 mM/hr compared to the case without baffle at the superficial gas velocity of 0.018 m/s, relatively.