Effect And Mechanism Of Sludge Fermentation On Slurry Formation Characteristics Of Petroleum Coke-sludge-slurry

The increasing discharge of urban sludge and the difficulty of its harmless treatment are a major problem facing our country at present.Taking a certain proportion of petroleum coke,sludge,dispersant and deionized water to prepare sludge coke slurry as slurry fuel is an effective way to deal with it,but there is a defect that the slurry concentration decreases after adding sludge.In this study,the co-slurry of municipal sludge and petroleum coke from anaerobic fermentation was selected to study the effect of sludge fermentation on the characteristics of pulping with petroleum coke.Firstly,the effect of fermentation on sludge was analyzed by scanning electron microscope(SEM),Fourier transform infrared spectroscopy and TG-DSC,and then the pulpability,rheological properties and stability of coke slurry prepared from fermentation sludge were analyzed.The effect and mechanism of sludge fermentation on slurrying with petroleum coke were discussed and studied.The results showed that the yield stress of the slurry increased with the increase of the addition ratio of fermentation sludge.When adding fermentation sludge with a low mixed C/N ratio,the consistency coefficient increases and the rheological index decreases;when adding fermentation sludge with a higher mixed C/N ratio,the consistency coefficient decreases and the rheological index increases;when the fermentation sludge with high mixed C/N ratio is added,the consistency coefficient increases and the rheological index decreases with the increase of the amount of fermentation sludge added.According to the comparison of co-slurry of fermentation sludge under different fermentation conditions and petroleum coke particles,the research results show that the PCSS with mixed C/N=16 fermentation sludge has the best stability and maximum concentration,which is higher than that of PCSS with original sludge.A increment of concentration of 11.2% was achieved,and the stability of the slurry was maintained.The increase of the maximum concentration is due to the decomposition of the sludge flocs by fermentation,which leads to the release of the bound water in the sludge and the decrease of the viscosity.The reason for adding fermentation sludge to enhance the stability of the slurry is that although the fermentation reduces the structural strength of the coke slurry to a certain extent,the steric hindrance effect of the bubbles generated in the fermentation sludge leads to the improvement of the static stability of the prepared slurry,and the increase of the zeta potential on the particle surface after the sludge disintegration also promoted the improvement of the slurry stability.Therefore,it is possible to combine sludge anaerobic fermentation with sludge coke slurry preparation to maximize benefits,and it is a feasible method for sludge treatment in the future.