The Corrosion Inhibitor Availability Model

Abstract The traditional Corrosion Inhibitor Efficiency Model has been reviewed and shown to have some failings particularly with respect to the design of new facilities. The problem of considering a single, deterministic corrosion rate has been discussed and the distribution of corrosion rates about a mean (or modal) value has been considered. The role of a corrosion inhibitor to not only reduce the mean corrosion rate but also decrease the spread of corrosion rates has been highlighted. A Corrosion Inhibitor Availability Model has been introduced, the benefits of which are: A focus on the required corrosion rate.Removes focus from the mean corrosion rate only.Accounts for realistically achievable corrosion rates.Identifies the importance of the availability of corrosion inhibitor.Accounts for the interruption or the absence of inhibitor from time to time.Does not allow dangerously low corrosion allowances to be used. The limitations on the use of corrosion inhibitors has been discussed and a Corrosion Inhibitor Risk Category has been introduced. Data from the Prudhoe Bay operation in Alaska is used to support the ideas discussed. Much of the discussion focuses on the design of new facilities. However, the approach is equally applicable to existing operations.