Slag-coated wall structure technology for entrained flow gasifiers

Abstract

An extensive research and technology base for utilization of slag as an active protective coating on wall structures has been developed. This work was aimed initially at MHD topping cycle components. Duration testing under conditions very severe relative to those considered for gasifier operation has shown that negligible wall damage occurs over hundreds of hours of flow. Complete and uniform slag coverage of properly designed water wall structures is obtained, resulting in operation in regimes heretofore inaccessible because of refractory dissolution or wall erosion. The active slag coating serves as an effective erosion barrier, with particle impact and gas flow shear load absorbed by the flowing self-renewing slag coating. Multiple shutdowns and restarts, including in-situ development of a slag coating on a bare wall, have been demonstrated. Improved durability in high temperature reaction zones is projected, using this technology. An advanced technology two stage entrained flow gasifier, utilizing high peak temperature and velocity to achieve high carbon conversion by pyrolysis, and low overall oxygen consumption, is outlined.