Study On Influence Factors And Hydrogen Production Way Of Wet Sludge Pyrolysis

With the progress of city modernization, municipal wastewater sewage sludge werealso showed increasing trend, how to effective treatment and disposal of sewage sludgeare still to be resolved. The traditional sludge disposal methods cannot meet the socialdemand, pyrolysis get the attention of research workers with its advantage witch maximizethe energy recycling in minimal hazard by-product. Wet sludge moisture can promotehigh-quality combustible gas generated, from the economic perspective, this papersumming up the experience and continue to explore the wet sludge pyrolysis hydrogenoptimal conditions, the advantage of wet sludge pyrolysis directly, the formation and thetendency of H₂, the main contents and conclusions are as follows:The experiment system was composed of tube type high temperature electric heatingfurnace, steam generator and other accessories, summed up the influence regular pattern ofpyrolysis products and gaseous components of single batch feeding amount, reaction timeand the way to heating-up. The experimental results show that, when final tempreture is1000℃, a single batch of feed rate for250g wet sludge can get high quality hydrogen richgas in a short period of time for the divice of this experiment; Reaction has been basicallycompleted in45min, the majority of hydrogen rich gas has generate. Use the heating modewitch the first setting temperature is the end temperature, improves the heating rate, moreintermediate product take part in high temperature catalytic reaction and the two cleavagereaction, leading to CH₄and CO₂content with lesser degrees of reduction, while H₂and COcontent has been substantial growth. Under the same conditions, wet sludge pyrolysis canget more H₂and CO high quality gas than dried sludge gasification.Analyses the three-phase product compositions and elements content, investigatingthe way hydrogen product, and predict the hydrogen product trend. After drying the rawsludge may contain substances: alcohol, amine, ester, ether, alkenes, olefins, acid, aliphatichydrocarbons and aromatic compounds, after more than600℃of pyrolysis reaction, the components are reduced accordingly; The collected tar were consisted of the aromatic ring,heterocyclic compounds and a small amount of nitrogen, oxygen containing compoundsmainly. With the increase of temperature, C, H, O, N, S were reduced in different degree,in addition, more water take part in the response, show that water involved in largelypromoted the gaseous products generated, which accord the gaseous product trend,moisture content heavily involved in the lead directly to the gaseous products of H₂andCO content increase; with the advance of pyrolysis, we can get higher H₂and CO contentand gas low calorific value, because when the temperature reaches1000℃, thermaldecomposition reaction can obtain the maximum energy supply, those can promote thesteam reforming reaction, two cracking reaction and condensation, cyclization reaction;the reaction generate H₂were: dehydrogenation reaction of large molecules, dissociation,condensation, cyclization of intermediate products, and the water vapor reforming reaction;using Excel fitting the experience equation of the wet pyrolysis process product changes,forecast that continue to expand the range of temperature, gas production rate willcontinue to rise, H₂plus CO content and H₂/CO value will also be a correspondingincrease.