Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy—IV. Reactor experimentation with vacuum residue

The combined pyrolysis and steam-gasification of petroleum vacuum residue was performed using a 5-kW aerosol-flow solar chemical reactor tested in a high-flux solar furnace in the temperature range 1420–1567 K. The feedstock was continuously injected as a liquid spray at 423 K into the reactor's cavity along with a coaxial steam flow at a H2O/CH2O/C molar ratio in the 1.1–7.2 range, and directly exposed to concentrated solar radiation at concentration ratios exceeding 1800 suns. The degree of chemical conversion after a single pass of 1-s residence time attained 50% at 1472 K, producing high quality syngas of composition 68% H2H2, 15% CO, 14% CO2CO2, and 2% CH4CH4. The process performance indicators, namely, carbon conversion and energy efficiency were generally inferior to those obtained for the solar steam-gasification of petcoke under comparable operating conditions.