Failure analysis of wood gasifier vessels

Gasification of biomass or streams containing biomass offers a means to produce syngas that can be combusted directly or converted to higher value products. Oak Ridge National Laboratory (ORNL) staff members have investigated and reported on corrosion that was encountered in several types of biomass gasifiers the most recent of which involved failure of carbon steel shells of wood chip gasifiers. The investigation of these wood chip gasifiers determined that incomplete gasification of the biomass resulted in formation of a wide range of organic compounds including low boiling point organic acids. These acids, unintentionally, had access through a narrow pathway to the surface of the carbon steel vessels, and condensation of the acids apparently caused severe corrosion of the carbon steel in a very limited area around the circumference of the vessels. Laboratory studies were conducted in a simulated environment, and several alloys with sufficient corrosion resistance were identified.