Study On The Effect Of Soild Waste As Catalyst On Pyrolysis And Reduction Of Sludge

In order to achieve the reduction,harmless and reclamation utilization of excess sludge and further reduce the cost of sludge disposal,this research firstly analyzes the sludge pyrolysis catalyst that has been studied by the former and selects KCl,CaO,Fe₂O₃,Na₂CO₃ and coke as the representation of the original catalysts to do the sludge catalytic pyrolysis experiments.Then,based on these experiments,three kinds of solid wastes:fly ash,coal gangue and iron tailings are chosen as new catalysts to explore their feasibility and catalytic ability as sludge pyrolysis catalysts.In the previous research on sludge catalytic pyrolysis,the verification of sludge pyrolysis mechanism has always been a difficult problem.This study uses the thermogravimetric analyzer and muffle furnace to carry out experiments on sludge,coke and its mixture with catalyst and explore how the catalysts promote the reduction of sludge during sludge pyrolysis.Meanwhile,the main action sites of the catalysts during the process of sludge pyrolysis were verified.The results illustrate that:?1?600°C is the best final temperature of pyrolysis for the liquid production,and 800°C is the best final temperature for gas production to ensure its economic benefits;?2?For the aspect of common sludge pyrolysis catalyst,Na₂CO₃ has the best effect on sludge pyrolysis reduction,while the quality of gas-liquid production under KCl and CaO catalysis are the best during sludge pyrolysis;?3?The industrial and mining solid waste catalyst can further improve the gas-liquid yield of sludge pyrolysis and reduce the solid residue at the same time.Moreover,the best comprehensive effect belongs to coal gangue,followed by iron tailings and fly ash;?4?Thermogravimetric analysis shows that the addition of sludge pyrolysis catalyst can reduce the activation energy of sludge pyrolysis and make sludge organic matter be decomposed more easily;?5?Sludge pyrolysis reduction experiments show that the catalytic effect of the catalyst on the sludge pyrolysis residual carbon is greater than the direct effect on the sludge;?6?Solid wastes can be applied to the sludge pyrolysis as sludge pyrolysis catalysts.