Effects of Gasification Temperature and Catalyst Ratio on Hydrogen Production from Catalytic Steam Pyrolysis-Gasification of Polypropylene

A two-stage reaction system was used for the pyrolysis-gasification of polypropylene in the presence of steam and a Ni/CeO2/Al2O3 catalyst. The influence of catalyst ratio (0, 0.25, 0.5, 1.0, and 2.0) and gasification temperature (600, 700, 800, and 900 T) on the production of hydrogen were investigated. The reacted catalysts were characterized using thermogravimetric analysis and scanning electron microscopy-energy dispersive X-ray spectrometry. The maximum potential hydrogen production was only 5 wt % without the catalyst, however it increased to 52.8 wt % in the presence of the Ni/CeO2/Al2O3 catalyst at a catalyst/polypropylene ration of 1. Increasing the catalyst: polypropylene ratio resulted in an increase in hydrogen production and a decrease of coke deposited on the catalyst surface but showed little influence on the CO and CO2 concentrations. Increasing the gasification temperature resulted in a marked increase in potential hydrogen production from 13.4 to 52.0 wt %, as the gasification temperature was increased from 600 to 900 degrees C. In addition, the CO concentration increased from 9.3 to 27.2 vol %, and CO2 concentration decreased from 17.8 to 4.5 vol % with increasing gasification temperature.