Influence of sewage sludge on the rheological properties of petroleum coke–water slurry

Abstract

ABSTRACTEnvironmental concerns have stimulated proper treatment in utilizing sewage sludge derived from different industries. The main objective of the present study is to prepare high‐quality petroleum coke–sludge slurry (PCSS) with low viscosity and good stability by adding sewage sludge into petroleum coke–water slurry (PCWS), and a systematic investigation of the rheological properties of PCSS and PCWS, along with the sewage sludge, is conducted. The experimental results show that the PCWS is a dilatant fluid and has inferior stability; sewage sludge is a pseudoplastic fluid. As a certain amount of sewage sludge is added into PCWS to obtain PCSS, rheological properties are changed from a shear‐thickening property to a shear‐thinning property. Raw sewage sludge has higher bound water content and larger viscosity. Alkaline chemical additives are selected as sewage sludge modifiers to turn bound water into free‐flowing water and reduce the viscosity. The static stability of PCSS was analyzed by the water separation ratio. Results indicate that sewage sludge has a significant impact on the static stability of PCSS. Water separation ratio decreases and the static stability is improved after addition of the sewage sludge. The higher the sewage sludge amount, the better the static stability of the PCSS. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.