Pyrolysis behavior of fuels in a drop-tube reactor: Kinetics at different temperatures and high pressures up to 100 bar

Thermochemical conversion processes, like pyrolysis, play a major role in the energetic and non-energetic utilization of carbon resources. For many industrial applications of conversion technologies, great potential is identified in the transition to higher pressures. A number of pressurized pyrolysis studies are performed mostly up to 30 bar, while experimental data at higher pressures up to 100 bar are required for the design of the next generation of industrial plants. All experiments are carried out in a drop-tube furnace (DTF) at pressures varying in the range 5–100 bar (g) and temperatures of 600–800 °C with continuous feeding and constant temperature profile leading to high particle heating rates. The pyrolysis behavior of the samples of coal and sewage sludge as well as their blend are investigated with the focus on the effects of pressure and temperature on the product yields and pyrolysis kinetics. Respective yields of all pyrolysis products (gaseous, liquid (tar/oil, water), and solid phase (char)) are related to the process conditions. Kinetic parameters (activation energy, frequency factor) for the main gas components H 2 , CO, CO 2 , and CH 4 are determined, which revealed a number of parallel secondary decomposition reactions and agreed with the literature.