Ceramic extends air distributor life

摘要

By switching from stainless steel to a ceramic construction based on refractory grade alumina bonded silicon carbide for its FCC air distributor nozzles, a refiner expects a significantly extended lifetime for the distributor nozzles in severe operating conditions. Within a FCC unit, there are a number of different types of air/steam rings. In each of these there are small nozzles that distribute air over the grid, which creates the fluidised bed. These FCC air distributor nozzles are subjected to high temperature, high velocity, erosive environments. To function in this harsh environment, FCC air distributor nozzles have historically been fabricated from a variety of erosion-resistant metallic materials. While these materials are proven effective at reducing rates of erosion, by their nature, they do not perform well in sliding abrasion or at elevated temperatures. As such, they pale in comparison to most ceramic bodies. Ceramic materials are widely accepted and proven to be more resistant to erosion than metallic materials at acute angles of impingement. The characteristics that impart erosion resistance also tend to make these materials suited for nozzle applications that rely on consistent orifice diameters for performance and reliability.