Coal pyrolysis behaviors at supercritical CO2 conditions

In this study, a product gas yield and carbon conversion were measured during the coal pyrolysis. The pyrolysis process occurred under two different atmospheres such as subcritical (45 bar, 10C) and supercritical CO2 condition (80 bar, 35C). Under the same pressure (80 bar), the atmosphere temperature increased from 35C to 45C to further examine temperature effect on the pyrolysis at supercritical CO2 condition. For all three cases, a power input supplied to heating wire placed below coal bed was controlled to make coal bed temperature constant. The phase change of CO2 atmosphere and subsequent pyrolysis behaviors of coal bed were observed using high-resolution camcorder. The pressure and temperature in the reactor were controlled by a CO2 pump and heater. Then, the coal bed was heated by wire heater to proceed the pyrolysis under supercritical CO2 condition.