CO2 gasification process performance for energetic valorization of microalgae

In this study, CO2 gasification process of a marine biomass (Nannochloropsis gaditana microalgae char) has been evaluated. The experiments have been carried out according to a central composite design (CCD), by using a high-pressure thermogravimetric analyzer (HP-TGA). The effect of temperature, total pressure and gasifying agent volume concentration on the CO2 gasification process was studied. Within the CCD studied range, the process performance, expressed as reactivity and gasification rate at 50% conversion, was positively influenced by the increase of temperature and pressure, while CO2 concentration effect was negligible. Empirical models describing the gasification performance as a function of temperature and pressure are presented and discussed. The proposed models allow a more realistic approach of the microalgae gasification process, in comparison with other models where the catalytic effect is often neglected. This study reveals useful process aspects for the development and implementation of microalgae CO2 gasification at industrial scale.