Catalytic pyrolysis of cotton straw by zeolites and metal oxides

Abstract

The influences of zeolites and metal oxides on the pyrolysis of cotton straw have been studied by thermogravimetric analysis (TGA). And performance of different catalysts to volatile and yield of ash was compared. The results showed that the catalytic pyrolysis experienced three stages: water losing stage, activated pyrolysis stage(APS), passive pyrolysis stage(PPS). The passive pyrolysis stage for pure cotton straw was small. The addition of the catalysts decreased the percent of volatile conversion for activated pyrolysis stage, but with the decreasing temperature for passive pyrolysis stage and increasing the percent of volatile conversion for passive pyrolysis stage. These catalysts promoted the pyrolysis of lignin, but showed less performance to the pyrolysis of cellulose and hemicellulose. The yield of ash increased in the presence of catalysts,and the yield was higher when catalyzed by metal oxide than by zeolite.