Hydrogen generation from polyvinyl alcohol-contaminated wastewater by a process of supercritical water gasification

Abstract

Gasification of polyvinyl alcohol (PVA)-contaminated wastewater in supercritical water (SCW) was investigated in a continuous flow reactor at 723–873 K, 20–36 MPa and residence time of 20–60 s. The gas and liquid products were analyzed by GC/TCD, and TOC analyzer. The main gas products were H 2,CH 4, CO and CO 2. Pressure change had no significant influence on gasification efficiency. Higher temperature and longer residence time enhanced gasification efficiency, and lower temperature favored the production of H 2. The effects of KOH catalyst on gas product composition were studied, and gasification efficiency were analyzed. The TOC removal efficiency ( R TOC), carbon gasification ratio ( R CG) and hydrogen gasification ratio ( R HG) were up to 96.00%, 95.92% and 126.40% at 873 K and 60 s, respectively, which suggests PVA can be completely gasified in SCW. The results indicate supercritical water gasification for hydrogen generation is a promising process for the treatment of PVA wastewater.