novel one-shell high temperature and high pressure semi-continuous reactor has been developed for the study of the Boudouard reaction at temperatures up to 820 C and pressures up to 32.5 MPa. Semicontinuous gasification of charcoal using supercritical CO2 has been achieved at conversions up to 90.8% (w/w) at LSHV between 20 and 30h(-1) after 5-9h. A gasification model is proposed and validated. Effective rates of gasification (1.32 +/- 10.12) x 10(-6) to (6.10 +/- 2.03) x 10(-5) s(-1) were obtained. The results indicated that this method is technically feasible for the on-line production of high pressures streams of CO/CO2 in the lab for carrying out further chemistries, avoiding the use of CO high pressure bottles. (C) 2007 Elsevier B.V. All rights reserved.