Modifying existing preheater systems for improved productivity and efficiency [cement industry]

Three cases of preheater/precalciner modifications covering a production capacity ranging from 1500 to 4500 mt/d for plants in France, Canada and the USA are described. The first example deals with the addition of an RSP type furnace to an existing PREPOL-AT precalciner for capacity enhancement and improvement of circulating elements behavior within the kiln. The second covers the replacement of an ACL grate preheater by a one-stage PREPOL-AS calciner enabling low alkali clinker production from high alkali, high sulfur, high kerogen raw materials in an environmentally sound manner. The third example shows the replacement of two underdimensioned Fuller-SF-calciners of a two-string preheater kiln by one large FLS type SLC-S precalciner in connection with the installation of a 10-50% capacity range bypass system. All three kiln conversions have been basically successful and able to meet the expectations almost entirely. However, since they came onstream a comparatively short while ago, some optimization and fine tuning work still has to be completed