Study on the effect of cyclic catalytic pyrolysis on sludge pyrolysis products

Pyrolysis technology has become a hot issue in the industry of harmless treatment of sludge in recent years. The present ex-situ catalysis process suffers from the defects of unidirectional flow of pyrolysis steam, easy to form coke buildup on the catalyst surface, and poor heating value of the output heavy tar, which is difficult to be reutilized. This paper designed a cyclic catalytic cracking by pyrolytic steam process to optimize the above defects: under the optimal experimental conditions (pyrolysis starting temperature was 500 degrees C, final temperature was 800 degrees C, iron-based carbon catalyst dosage was 4 g, and motor speed was 1050 r/min), this process generated more pyrolysis gas and light tar. The increase in pyrolysis temperature had the most significant effect on py-rolysis gas yield, the dosage of iron-based carbon catalyst had the most significant effect on pyrolysis gas composition, and the increase in motor speed had the most significant effect on tar cracking. The cyclic catalytic cracking by the pyrolytic steam process can increase the residence time of pyrolysis steam in the reaction unit and promote the secondary cracking, catalytic, and reforming effects of tar.