Study On The Gas Generation Characteristics And Pyrolysis Process Of Sewage Sludge Fluidized Bed Gasificatio

Sewage sludge（referred to as sludge）pyrolysis and gasification technology can effectively realize the clean energy of sludge,so they have been paid more and more attention by researchers.Based on the research status of sludge pyrolysis and gasification technology,this paper studied the gasification gas generation characteristics and pyrolysis process（including the basic characteristics of pyrolysis gas and pyrolysis tar）in the sludge fluidized bed.In order to provide theoretical basis and technical support for the clean energy utilization of sludge.In the study of gasification gas generation characteristics,it could be known that:When the sludge was gasified by air,steam and air-steam respectively,increasing the gasification temperature increased the contents of H₂ and CO in the gasification gas and its yield,carbon conversion rate,organic phase,but decreased the contents of CO₂,C_nH_m and the low heating value.The moisture content of sludge had a great influence on the composition of air gasification gas,but had little effect on the composition of steam gasification gas and air-steam gasification gas.Among them,the gasification performance（ies the low heating value,yield,carbon conversion rate,organic phase conversion rate,energy conversion rate）of air and steam was the best when the sludge moisture content was 16%.When the sludge from the multi-stage AO sewage treatment process and the AAO sewage treatment process was gasified under three gasification media,the multi-stage AO process sludge was more likely to generate H₂ and CO,while the AAO process sludge was more likely to generate CO₂ and C_nH_m.The gasification performance of the multi-stage AO process was the best in the steam gasification.And in AAO process,the carbon conversion rate was the highest in air gasification and the low heating value was highest in air-steam gasification.During steam gasification,when the ratio of steam to sludge mass（S/B value）was 1.5,the content of H₂ and CO was the highest,while the content of CO₂,C_nH_m and gasification performance were the lowest.There was no significant difference in gas composition and gasification performance between wet sludge"air"gasification and dry sludge"air-steam"gasification.In the study of pyrolysis gas generation characteristics,it could be known that:Compared with the multi-stage AO process sludge pyrolysis,the AAO process sludge pyrolysis was easier to form CO and CO₂,and the organic phase conversion rate and energy conversion rate were higher,but it was not easier to form H₂ and C_nH_m;Increasing the moisture content of sludge increased the content of CO₂,C₂H₄,and decreased H₂,CH₄,CO.In the study of the basic characteristics of pyrolysis tar,it could be known that:Both T-AAO tar and T-AO tar contain aromatic hydrocarbons,aromatic hydrocarbon derivatives,heterocyclic compounds,aliphatic compounds and alicyclic compounds.Among them,the yields of acenaphthylene,fluorene,indole,and quinoline in T-AAO tar were higher,while the yields of 9,10-anthracenedione and cholesteric compounds in T-AO tar were higher.With the increase of sludge moisture content,the low heating value of pyrolysis tar,the yield of aromatic hydrocarbons,aromatic hydrocarbon derivatives and alicyclic compounds decreased,the yield of heterocyclic compounds increased,and the aliphatic compounds disappeared.The pyrolysis processes of the three tars were divided into three stages:volatilization and pyrolysis of light organics,pyrolysis of heavy organics,and decomposition of refractory organics.