Supercritical water gasification (SCWG) of coal is a promising technology for clean coal utilization. In this paper, hydrogen production by non-catalytic partial oxidation of coal was systematically investigated in supercritical water (SCW) with quartz batch reactors for the first time. The influences of the main operating parameters including residence time, temperature, oxidant equivalent ratio (ER) and feed concentration on the gasification characteristics of coal were investigated. The experimental results showed that H-2 yield and carbon gasification efficiency (CE) increased with increasing temperature and decreasing feed concentration. CE increased with increasing ER, and H-2 yield peaked when ER equaled 0.1. CE increased quickly within 1 min and then tended to be stable between 2 and 3 min. In particular, complete gasification of lignite was obtained at 950 degrees C when ER equaled 0.1, as for bituminous coal, at a higher temperature of 980 degrees C when ER equaled 0.2. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.