Abstract
Ash deposits in steam-generating units have been becoming more troublesome and have presented a design and operating problem. It is recognized that troublesome deposits are characterized by a high content of low-temperature-melting constituents. This paper is concerned with the addition of high-temperature melting-point compounds to the fuel oil to elevate generally the melting point of the aggregate above the troublesome temperature level. Fusing temperatures of intimate mixtures of oil ash with many additive compounds were determined. Alumina was found to be the best material, with magnesium and calcium oxides showing promise. The fusing-temperature tests were substantiated by pilot-furnace-firing tests and these results in turn were applied to further experimentation on a full-sized unit. Alumina was the first additive used in a steam-generating unit of the Florida Power Corporation. Alumina was later replaced by dolomite. Both materials raised the fusing temperature of the ash to the extent that the work of removal was considerably decreased, but dolomite proved to be the most desirable from an operating as well as an economic standpoint. Other benefits, such as decreasing the acidity of the ash in the unit, were apparent when using dolomite. The use of the process is now being extended to other units. An arrangement of necessary equipment with detailed description of the components is appended.
