IMPROVEMENT OF HEAT UTILIZATION SYSTEMS WITH THERMAL PROCESS STABILIZATION IN ROTARY KILNS

This article is devoted to improving heat utilization systems for industrial and municipal heat supply. It outlines methods for enhancing the cooling systems of kilns used in the firing of construction materials, identifies ways to stabilize the thermal regime, and establishes the conditions for developing functional layouts for furnace units. Rotary kilns, operating under varying environmental influences such as air temperature, wind speed, solar radiation, and atmospheric precipitation, lose up to 30% of their heat through the lateral surface into the surrounding environment. These external factors negatively affect the thermal condition of the furnace unit, leading to overheating during warm periods and overcooling in cold seasons, which in turn decreases the durability of the lining and the quality of the produced materials. Typically, natural cooling of the kiln side surface is assumed in order to maintain the necessary internal surface temperature and extend the lining’s lifespan. However, this is an uncontrolled process with the aforementioned disadvantages. One approach to increasing the efficiency of fuel combustion heat utilization is the implementation of a regulated cooling system for rotary kilns. One possible solution is a recirculating channel design, which relies on the repeated use of the heat carrier flow. The share of recirculated flow increases as outdoor temperature decreases. Under summer design conditions, the system operates as a direct-flow type, delivering the entire stream to end users. In winter conditions, air is supplied from the bypass line. Based on these considerations, formulas are derived for determining the main parameters of the stabilizing cooling system for rotary kilns, intended for residential and municipal heat supply applications.