Title : Catalytic hydrothermal gasification of organic compound
Abstract:
Nearly many studies on gasification of organic compounds under hydrothermal or supercritical water conditions have been performed. In this study, we conducted the catalytic hydrothermal gasification of diluted lactic acid. Several catalysts were used for comparison in catalytic activities. We chose activated carbon, silica alumina and Nickel on silica alumina and the prepared Nickel on activated carbon as catalysts. Nickel on activated carbon catalyst was prepared as follows: Nickel nitrate and the activated carbon were mixed physically and were carbonized in nitrogen flow at 873 K for 1 hour. In gasification experiment, 5 mL of 2 wt.% lactic acid aqueous solution and 0.1 g of solid catalyst were filled in a stainless-steal reactor. The reactor was plunged into an oil bath preheated to a temperature of 250 °C, then the reaction pressure increased rapidly up to the saturated vapor pressure at the temperature. After an elapse of the reaction time, the reactor was immediately soaked in a cool water bath. The total organic carbon in the aqueous solution was estimated using a TOC analyzer. Gasification conversion was calculated from TOC measurement on the basis of carbon in the solution. Conversion of reactant (lactic acid) was estimated from the concentration before and after the reaction. Gasification conversion reached 20% with activated carbon, only 10% without the catalyst. The changes in the soluble products distribution with passage of time were examined. The other organic compounds such as acetaldehyde were still existent after the reaction for 3 h. These compounds are judged to be inactive against the gasification.
