Method for two-phase flow hydrodynamic cleaning for piping systems

Abstract

A method for hydrodynamic cleaning of a piping system using two-phase flow. A model for predicting peak wall shear stress for two-phase flow is used to determine an optimum flow rate ratio which achieves a maximum wall shear stress in the particular piping system to be cleaned. The optimum flow rate is first established by turning on the liquid and gas flows through the piping system to be cleaned and allowing the flow to reach steady state conditions. The back pressure of the system is measured and the optimization model is used to determine the optimum flow rate ratio. Once the optimum flow rate ratio has been calculated, the liquid flow rate and the gas flow rates can be adjusted such that the optimum ratio is achieved. The two-phase back pressure is then measured to verify that the optimum flow rate ratio has been used. This is done by comparing the measured optimum two-phase flow back pressure with the initial two-phase back pressure used in the equations. If there is a variance between the two back pressures then the measured back pressure is substituted into the equations for the initial back pressure and the optimum flow rate ratio is recalculated. This step is repeated until the measured back pressure is equal to the back pressure used in the calculations. Cleaning is then performed at that optimum flow rate ratio.