Selection of materials for low-temperature black liquor gasification

Increased energy efficiency, reduced emission of pollutants, and inherently safer designs give black liquor gasification systems the potential to replace black liquor recovery boilers. However, there are significant problems that must be addressed, not the least of which is the selection of suitable materials for containment of the processes associated with gasification. One of the two systems considerably ahead of all others in terms of development efforts and commercialization employs a low-temperature process which operates below the melting point of the salts. Descriptions of both systems and the operating environments are presented, as well as a summary of the performance of materials in these systems. Laboratory studies simulating the gasifier environments are currently underway, and initial results of these studies reveal significant materials issues to be resolved. Using proprietary software, corrosion rate predictions have been made, and their projections summarized.