Microwave Pyrolysis Of Sewage Sludges And Analysis On The Strucure And Components Of Pyrolytic Products

Sewage sludge is the byproduct of wastewater treatment plant. Along with the output of industrial and urban waste water rapidly increase,the quantity of sewage sludge is increase.The composition of sewage sludge is very complicated. The baleful compositions of sewage sludge such as heavy mental,virus, parasite,organic matter and effluvium will seriously effect environment of urban.The disposal of sewage sludge is a matter of great concern. Now,people discover that sewage sludge is a kind of resource. As an alternative,the pyrolysis of sewage sludge can convert sewage sludge to resources and greatly decrease quality. Pyrolysis of sewage sludge which have adventages of celerity,saving energy and low cost is the directional development of diposoal of sewage sludge.In this thesis, a microwave pyrolysis process for disposal different sewage slugdes of Dalian has been proposed.This paper studied the temperature evolution during microwave treatment wet and dry sludge.This paper also researched the performance of active carbon, carbonaceous residue,SiC, graphite and admixture of SiC and graphite to absorb microwave energy. The effects of pyrolysis conditions including microwave power, microwave heating time, the amount of microwave absorber and the putting way were investigated.In order to gain most amount of oil,the conditions of pyrogenation confirmed.At the same time, GC, FT-IR, GC/MS and XRF etc technologies are used to analyse on the strucure and components of pyrolytic products The effects of microwave power,microwave absorber and kind of sewage sludge on characteristics of productions were also investigated.The results show that the temperature of the sewage sludge only reach about 300°C when it was radiated by microwave.The addition of microwave absorbers into sewage sludge can achieve the pyrolysis of sewage sludge at high temperature by microwave radiation. The gas product of pyrolysis contain the CO,H₂ and some hydrocarbon gases (the content of CO and H₂ was higher than 72%) and can be used as clean fuel and rude materials of the syngas. The liquids product can be separated as water and oil.The oil yield of chemical plan sewage sludge was higher than other kind of sewage sludge. The main components of oil are aliphatic compounds and monoaromatics. The oil from pyrolysis of dry sewage sludge contain about 40% aliphatic compounds and about 33% of monoaromatics.The pyrolysis oil from pyrolysis sewage sludge of chemical plant of Dalian using carbonaceous residue as absorber contain about 71% aliphatic compounds and about 10% of monoaromatics.The oil can not only be directly used as fuel but also be separated to get chemical products.It can be concluded that pyrolysis of sewage sludge by microwave can come true.This method can not only dispose sewage sludge in effect but also.utilize sewage sludge.The microwave-heating method makes the processes of pyrolysis of sewage sludge fast and energy saving than conventional methods.