Abstract: Corrosion resistance of valves or fittings exposed to corrosive attack by the environment in which they are normally used can be improved by covering those portions of the valve or fitting of thinner cross-section by a thin metal sleeve fabricated from an alloy resistant to corrosive attack by the environment.

Abstract: A process for enhancing heat transfer between combustion products formed in a fluidized bed combustion (FBC) reactor and the water-containing tubes surrounding the reactor wherein particles of an inert material, e.g., mineral calcium sulfate (gypsum), having a spheroidal shape ranging in size from about 50 to 1000 .mu.m and having a Moh's hardness of between 2.0 and 4.0 are introduced into the reactor in the presence of a solid fuel and an oxygen-containing gas. Introduction of such particles into the FBC reactor increases the particle density within the reactor thereby increasing radiant and convective heat transfer between the circulating bed and the surrounding water cooled walls. The improved process allows more precise control of the operating temperature regime. Erosion of the reactor walls is also substantially reduced.