Study on the catalytic gasification of alkali lignin over Ru/C nanotubes in supercritical water

Abstract

Aiming at the degradation-resistant characteristic of alkali lignin, gasification of alkali lignin in supercritical water was carried out in a batch reactor with Ru/C nanotubes as catalyst. The effects of temperature, water density, time, reactant concentration, catalyst amount as well as the catalytic efficiency on the gasification of alkali lignin were examined. The optimum conditions obtained with single factor analysis are as follows: reaction temperature 600°C, water density 0.1284 g/cm3, reaction time 60 min, reactant concentration 3.0%, and catalyst amount of 0.5 (g/g alkali lignin). The results show that high temperature, high water density (or pressure), long reaction time, low reactant concentration and moderate amount of catalyst will be in favor of the gasification of alkali lignin in supercritical water. The alkali lignin gasification efficiency and carbon conversion reaches 73.74% and 56.34%, respectively, under the optimal reaction conditions. Hydrogen production capacity is also significantly improved.