A study on the mechanism research on cellulose pyrolysis under catalysis of metallic salts

Experimental research on cellulose pyrolysis under catalysis of metallic salts was done on a thermobalance and a rapid pyrolysis system. Thermogravimetric analysis showed that K⁺ catalyzed the formation of active cellulose strongly and decreased the activation energy of cellulose pyrolysis. Experimental results indicated that K⁺ would promote the formation of char and restrain the production of bio-oil largely. Fe²⁺ had a similar catalysis effect on cellulose pyrolysis with K⁺. Fe²⁺ particularly catalyzed the formation of small molecule gaseous product while K⁺ the formation of char. The addition of K⁺ or Fe²⁺ resulted in a reduction of levoglucosan formation, and enhanced the production of hydroxyacetaldehyde and other small molecule components. Levoglucosan and hydroxyacetaldehyde were formed by the decomposition of active cellulose in a parallel mode. The secondary cracking of levoglucosan would also produce hydroxyacetaldehyde. A modified cellulose pyrolysis mechanism model was proposed based on the B-S model.