Effects Of Gasification Temperature And Catalyst Ratio On Hydrogen Production From Catalytic Steam Pyrolysis-gasification Of polypropylene

摘要

A two-stage reaction system was used for the pyrolysis-gasification of polypropylene in the presence of steam and a Ni/CeO_2Al_2O_3 catalyst. The influence of catalyst ratio (0, 0.25, 0.5, 1.0, and 2.0) and gasification temperature (600, 700, 800, and 900 ℃) 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/CeO_2/Al_2O_3 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 CO_2 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 ℃. In addition, the CO concentration increased from 9.3 to 27.2 vol %, and CO_2 concentration decreased from 17.8 to 4.5 vol % with increasing gasification temperature.