The ASSET project - A corrosion engineering information system for metals in hot corrosive gases

Corrosion of metals and alloys in industrial equipment is an important consideration in terms of safety, economics, and process design. This paper reviews how corrosion of alloys in process equipment can be identified, simulated, and managed. The discussion highlights the following: several corrosion mechanisms prevalent in high temperature process equipment; laboratory corrosion testing procedures to simulate conditions in operating equipment; and an approach to predict corrosion-limited equipment lifetimes at high temperatures. Corrosion of alloys by exposure to complex gases is discussed for temperatures of 200-1100degreesC. Many alloys are based upon combinations of iron, nickel, iron-chromium, and iron-nickel-chromium. These alloys are used in high temperature corrosive conditions even though there are often limited corrosion data available to predict lifetimes. We can correlate corrosion defined by the total metal penetration with exposure conditions such as the temperature, exposure time, and gas composition. This allows compilation of high temperature corrosion data so that engineering decisions can be made with respect to lifetime, maximum allowable temperature, and influence of gas composition, by analysis of corrosion data from well defined conditions for a variety of alloys. The likely corrosion mechanism is determined, based on alloy composition, exposure conditions, gas composition, and temperature. This approach has been incorporated into software called ASSET (Alloy Selection System for Elevated Temperatures) and is used for failure analysis, equipment design, alloy selection, and alloy design.