Co-pyrolysis Of Municipal Sewage Sludge And Waste Biomass For Bio-oil

In order to utilize the waste biomass and mulnicipal sewage sludge maximumly,in this paper the co-pyrolysis process of waste biomass and sewage sludge in fixedbed were studied.Thermogravimetric analysis shows that the synergistic effect of water hyacinthon the sludge was more obvious than that of peanut shell on the sludge. Kineticsanalysis shows the pyrolysis alone of the sludge and the co-pyrolysis reactions of thesludge and different proportions of biomass could be described as two first orderreaction models. After adding the biomass with H free radical to the sludge, theactivation energy E at high temperature period was decreased obviously.The investigation of the fixed bed pyrolysis experiments shows that as the finalpyrolysis temperature or the mix proportion increased, the yield of the bio-oilincreased. Because of the catalytic effect of more lignin, at same conditions thebio-oil yield from the co-pyrolysis of peanut shells and the sludge was always higherthan that from the water hyacinth and the sludge.The analysis of liquid productsshows: with the increase of the blending ratio, the content of2-ethyl alcohol anddiethyl phthalate in the bio-oil from the co-pyrolysis of the water hyacinth and thesludge was reduced gradually. When the ratio of peanut shells and the sludge was4:1and the final pyrolysis temperature was600℃, in the bio-oil the content of alkanesacid was just1.04%. Due to the influence of the bio-oil composition, the calorificvalue of the bio-oil produced from the co-pyrolysis of the biomass and the sludge washigher than that from the individual pyrolysis of the sludge, the acid value and theviscosity were lower, but the final pyrolysis temperature and the blending ratio hadless effect on the acid value and viscosity of the bio-oil. So the optimal operationconditions were the mix ratio of4:1and the final pyrolysis temperature of600℃,and the bio-oil yield from the co-pyrolysis of peanut shells and the sludge was60.63%. Meanwhile, the calorific value, acid value and viscosity were respectively54.23KJ/g,19.49mg/g and42.83mm2/s.Gas phase product analysis of the co-pyrolysis of the sludge and the biomass shows that600℃and500℃were respectively beneficial to H2and CH4. In theco-pyrolysis gas product of the sludge and the biomass, the experimental values of thecontent of H2and CH4were higher than that of the linear addition values of theirindividual pyrolysis and the experimental values of the content of CO and CO2werelower, which indicated that the addition of water hyacinth or peanut shells was infavor of the production of H2and CH4. Solid phase product analysis of theco-pyrolysis of the sludge and the biomass shows when the mixing ratio of peanutshells and the sludge was1:1and the final pyrolysis temperature was600℃, thespecific surface area of the pyrolysis carbon was the largest, up to51.72m2/g. Theanalysis of XRD shows that the co-pyrolysis of water hyacinth and the sludge showedstrong characteristic peak of KCl and the co-pyrolysis of peanut shells and the sludgeonly showed the characteristics peak of SiO2which came from the sludge, indicatingthat there was no KCl in peanut shells. KCl played a catalytic role in the pyrolysisprocess, which also could explain why the co-pyrolysis rule of water hyacinth and thesludge was different from that of peanut shells and the sludge.