Water Wash Design Optimization with Simulation and Empirical Evaluation
15 December 2015
Petro-chemical refiners are required to move crude oil great distances throughout the refining process. Crude oil contains various salts which can lead to corrosion or plugging at various stages in the equipment. Water wash is of-ten implemented to scrub the salts from the process stream to mitigate corrosion risks. Two modes of pipe degradation are addressed in this work: acid corrosion and erosion due to high wall shear stress. The primary focus of this study is to define the parameters with largest impact on the reduction of corrosion and erosion. Distribution of injected water wash and downstream behavior of the excess fluid are the focus of this investigation. This study builds on previous empirical and simulation studies of water wash techniques. A hydraulic spray and multiple quill style injectors were investigated with a nominally uniform cross-flow. These results demonstrate the trajectory change as well as the change in spray plume characteristics over a range of spray types and operating conditions, including counter-current and cross-current operation. The experimental results were acquired with a LaVision Laser Sheet Imaging (LSI) and an Artium Phase Doppler Interferometer (PDI), to measure the spray shape, size, distribution characteristics as well as droplet size and velocity. The spray simulations were conducted using ANSYS FLUENT computational fluid dynamics (CFD) package in conjunction with custom spray injection methods developed in-house. Experimental results are compared with the simulation results to indicate the amount of wash water that can be entrained to interact with the gas stream for corrosion mitigation.