Diffusion‐controlled corrosion of agitated vessels containing oil‐water emulsions

The rate of diffusion‐controlled corrosion of the copper walls of a cylindrical agitated vessel in acidified FeCl3 solution was studied by measuring the weight loss and the increase of Cu2+ concentration with time using iodometry. Variables studied were impeller rotation speed, physical properties of the blank solution and oil concentration in the emulsion. The rate of dissolution of copper was found to increase with increase in impeller speed according to the equation: K = a′ V0.1, where K is the mass transfer coefficient, a′ is a function of oil concentration; V is the linear velocity of the impeller. The mass transfer coefficient of the corrosion process in blank solution was related to other variables by the equation: Sh = 0.000575 Re0.1 Sc0.33, where Sh is the Sherwood number, Re the Reynolds number and Sc Schmidt number. This equation could be used in the design stage, to calculate the thickness of the vessel which covers a certain life span in service under a given set of operating conditions.