Pyrolysis of municipal waste catalyzed with synthesized zeolite from steel making factory waste

Bio-oil is lacking of many quality standards required for the engine fuel. Many types of catalysts have been used to upgrade the bio-oil. However, they deactivated quickly or had high price. In this study, the catalytic pyrolysis of wastewater treatment plant sludge, pine wood, municipal waste and their mixture over synthesized zeolite (A type) from steel factory waste was studied. The results indicated that zeolite led to the slight increase of the bio-oil yield (46.0 to 46.2 wt%) and improved the quality of the bio-oil. For instance, it reduced the content of oxygen (49.45 to 19.65 wt%) and acids in the bio-oil. However, it was partially deactivated by the formation of coke. To further improve the quality of the bio-oil and decline the formation of coke, Ni, Ce, Mg and Mo were loaded on the surface of the zeolite. The results of the mixture feedstock pyrolysis indicated that Ni enhanced the yield of bio-oil slightly, while the other metals did not change it significantly. Ni led to higher amount of cracking and deoxygenation of the acids. Ce enhanced the content of oxygen-containing species in the bio-oil. Mg resulted in the higher amount of -OH containing compounds. Mo increased the amounts of acids, aromatics and alcohols in the bio-oil. Due to the high tendency of Ni for cracking, the highest amount of hydrocarbons in the gas was measured for that. The highest deoxygenation of bio-oil was achieved by Mo. Mo/zeolite had the lowest content of carbon, which indicated the lowest amount of coke.