Study On Catalytic Cracking Of Sewage Sludge

The treatment and disposal of swage sludge is important for a city to develop healthy.It is urgent to find approaches to treat sewage sludge properly.It is considered that the technical processes used for converting sewage sludge into oil is developmental potential new technology.But the quality of oil pyrolysised from swage ludge is not better enough for application,the upgrading of sluge oil is indispensable.In this work,it studied the sewage sludges from treatment factory that deal with wastewater with biological processes.Its objective is to evaluate the pyrolysis characteristics of sewage sludge by thermal gravitational apparatus.The oil rate under different conditions is obtained and the best reaction conditions for the low-temperature pyrolysis and the catalytic upgrading are confirmed, evaluating the characteristics of the two oil through elements analysis,thermogravimetric analysis and GC-MS analysis,electing and regenerating the calalyst.The experiments were done to study how these different technics conditions influence the oil rate. The results show that:for low-temperature pyrolysis,the best reaction temperature is confirmed which is 470℃, the best reaction time is 70min;for catalytic upgrading,the best pyrolysis temperature is 420℃,the best reaction time is 60min,the best catalytic upgrading temperature is 460℃,the proper dose of the catalyst isφ20mm×30mm.Comparing to low-temperature pyrolysis, the oil obtained from catalytic pyrolysis contains less oxygenated hydrocarbons and more monocylic aromatics compounds,making the oil advanced in capability and safety.Comparing the combustion character of pyrolysis oil and upgraded oil,the results show that the combustion processes of the two oil is similar,and they all can burning without ash left.The catalytic upgraded oil is more combustible in comparison to pyrolysis oil.The result of choosing catalysts experiment show that:more organic distillate was obtained when HZSM-5(50) used as catalyst,while less coke when Gaolin used as catalyst.It was found that coking is the main cause of deactivation and short life of catalysts through the experiment of regeneration of deactivation catalyst. Keywords:Sewage sludge; Low-temperature pyrolysis; Catalytic cracking; Catalyst;The quality of oil...