Gasification characteristics of alanine in supercritical water

Abstract

Alanine solution (1.0-3.0 wt%) was gasified in supercritical water using a tubular reactor at a temperature of 500 to 650°C and a pressure of 25 MPa for a residence time of 86-119 s and compared the gasification characteristic with our previous work, glycine. The identification and quantification of gaseous products were conducted by gas chromatography (GC) and the total organic carbon (TOC) in the aqueous phase was also determined. The carbon gasification efficiency of alanine rose with increasing reaction temperature and the gasification rate followed first order kinetics. It was well expressed with the Arrhenius equation. The gasification rate of alanine was identical to that of glycine. The effect of the methyl group in alanine is the production of methane and the dilution of nitrogen so that the alkaline effect is suppressed. The former explains the higher methane yield, and the latter results in a high carbon monoxide yield.