Carbon monoxide and hydrogen mass transfer in a stirred tank reactor
The United States uses petroleum for everything from fuels to plastics. Currently, the US is importing over half of its petroleum from foreign sources. If the access to these foreign sources should suddenly cease, the US would suffer huge economic hardship. Processes have been developed that convert renewable sources into bio-based fuels and plastics that are similar to similar petroleum-based plastics. One of these processes is synthesis gas fermentation, which takes any biological material, converts it into gases (primarily carbon monoxide and hydrogen), and utilizes microorganisms that convert these gases into fuels and chemicals. However, such processes are currently not economically feasible. It has been suggested that the limiting step in synthesis gas fermentation is the mass transfer of these gases into the liquid medium that supports the microorganism growth. A study has been undertaken to understand the mass transfer rate of carbon monoxide and hydrogen into water in a stirred tank reactor. Methods for determining dissolved carbon monoxide and hydrogen concentrations will be developed. These methods will be used to determine volumetric mass transfer coefficients for these gases over a range of impeller stirring speeds from N = 200 to 600 RPM and volumetric gas flow rates from Q = 1 to 6 L/min. The volumetric mass transfer rate will then be correlated to the power density and superficial gas velocity in the stirred tank reactor for each gas. These correlations will be compared to those currently found in the literature.