The use of biomass and recycled fuels speeds up corrosion, resulting in a significantly shorter superheater lifetime. Unmanaged corrosion also leads to failure risks and unplanned shutdowns. Dealing with corrosion is a cost for power producers. The Metso Corrosion Management solution tackles the effects of corrosion, optimizes the fuel diet and extends equipment lifetime. Power producers no longer need to avoid inexpensive, lower-quality fuels due to risks of corrosion.
Until now, the boiler has been run with just minimal dynamic information about possible corrosion problems. By incorporating its long experience in various fuels, superheater materials, processes, online measurement technology and process automation systems, Metso has created an eye that provides more information about what takes place inside the boiler.
The Metso Fuel Diet™ Corrosion Management solution measures and reports the level of corrosion and controls the amount of corrosive gases in the boiler. It gives relevant information for fuel diet optimization and helps plan preventive maintenance and replacement operations. With the solution, power plants are able to extend their superheaters’ lifetime, maximize fuel flexibility, optimize fuel economy and lower their environmental impact. It is a solution that offers rapid payback on the initial investment.
Reporting, control and prediction in one package
The Metso Fuel Diet™ alkali chloride induced high-temperature corrosion management solution consists of the following blocks:
- Metso DNA Corrosion Manager – Software for reporting, controlling and predicting high-temperature corrosion, and optimizing the fuel diet
- Metso Corrosion Reduction Analyzer – Online measurement unit analyzing the corrosivity of flue gases
- Measures and remedies – CorroStop additives and systems to take real-time preventive actions
The Metso Corrosion Reduction Analyzer consists of an analyzer unit and a sampling device. Using proven titration technology, the analyzer measures total chlorine concentration and effective sulfur concentration from the flue gas and calculates the flue gas sulfur/chlorine molar ratio for corrosion risk and rate evaluation.
Metso Corrosion Management provides a new possibility to monitor the boiler condition and control alkali chloride induced high‐temperature corrosion. It provides a control package to prevent superheater corrosion or to set corrosion at an acceptable level by modifying process parameters, dosing additive or setting the optimal fuel diet. The liquid CorroStop additives are ferric [Fe2(SO4)3] or aluminum sulfate [Al2(SO4)3], which are injected into the upper furnace upstream of the superheater region. Another option is to dose sulfur granulates into the fuel flow. This product is called CorroStop+. Predictability of the corrosion risk helps to avoid unplanned shutdowns. Service periods and maintenance actions can be planned in advance by knowing the real-time corrosion rate.