Abstract
Black liquor gasification systems have the potential to replace black liquor recovery boilers because of their increased energy efficiency, reduced emission of pollutants and inherently safer designs. 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. There are two systems that are considerably ahead of all others in terms of development efforts and commercialization: a low-temperature process that operates below the melting point of the salts and one that operates well above it. 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 that simulate the gasifier environments are currently underway, and initial results of these studies indicate there are significant materials issues to be resolved. Predictions of corrosion rate have also been made using proprietary software, and results of these projections are summarized.
