Thermogravimetric study of the devolatilization of hydropyrolysis chars

The devolatilization of hydropyrolysis (HyPy) chars formed at 485–850 °C under 3 MPa and chars formed at 580 °C under 0–5 MPa of H 2 and 3 MPa He is investigated in a thermobalance coupled to two gas chromatographs. The H 2, CH 4 and CO 2 released are analysed every 4 min and all are analysed at the end of the experiment. The amount of residual volatile matter in the chars decreases rectilinearly with the HyPy temperature, whereas their decrease is asymptotic with the HyPy pressure. The char formed under He contains 45% more residual volatile matter than that formed in the same conditions under H 2. The HyPy temperature must be limited if the char is to be burned in a boiler. The CH 4 formation is strongly dependant of the HyPy temperature.