Effects of the Types and Addition Amounts of Sludge on the True Rheological Properties of Petroleum Coke Slurry Flowing in Pipelines

Abstract

AbstractEffects of the types and addition amounts of sludge on the true rheological properties of petroleum coke water/sludge slurry (PCWS/PCSS) flowing in pipelines were investigated using the Tikhonov regularization method. Results show that PCWS of 59.8 wt% changes from pseudo-plastic fluid to dilatant fluid as the shear rate increases. However, PCWS of 63.4 wt% is a very complex fluid: shear thinning at low shear rate, followed by shear thickening over a critical shear rate, and a subsequent shear thinning at high shear rate. Rheological properties of PCWS have a significant change after the sludge was added. PCSS changes from dilatant fluid to pseudo-plastic fluid when the addition amounts of sewage sludge ascend to 10 wt%. Petroleum coke particles are trapped by the stable “network” structures, which are formed by flocculent sludge particles. The wall slip velocity of PCSS is higher than that of PCWS with the sludge amount increases, which is beneficial for pipe transportation. In addition, the wall slip velocity of PCSS containing sewage or petrochemical sludge increases with the wall shear rate increases, but the slip velocity of PCSS containing paper mill sludge first increases and then decreases.