Investigation of 'Sloughing Behaviour' of Wax Deposit from Paraffin mIxtures in Pipe Flow

Abstract

Sloughing of wax deposit from ‘waxy’ crude oils has been described in the literature whereby the deposit is postulated to dislodge from the pipe-wall due to changes in flow parameters. A bench scale flow loop apparatus was designed to carry out three sets of experiments wherein the deposit-layer at steady-state was subjected to step changes in the oil flow rate, the oil inlet temperature, and the coolant inlet temperature. Each of these parameters was varied at several levels, while allowing the deposition process to reach thermal steady-state at each level. It was observed that the deposit-layer thickness decreased gradually with an increase in each parameter. However, a complete or sudden dislodging of the deposit-layer was not observed at any point. A steady-state heat-transfer model was used to predict changes in the deposit mass as a function of variation in the selected parameters, and the predictions were found to match the experimental results adequately.