Investigation of Cement Kiln Process for Reducing Environmental Emissions

Abstract

Abstract The cement industry is one of the world's most important strategic industries, essential to every country's economic and infrastructure development. Also, its production is recognized as one of the growth indicators for any country. In cement production, the rotary cement kiln is one of the main components that play a significant role in producing environmental pollutants such as NOX, VOC, CO, and CO2. Hence, this research aims to determine the concentration of pollutants gases and investigate ways to reduce their emissions, especially carbon monoxide, in different conditions in the cement kiln process. The rotary kiln is a Horizontal cylinder inclined with a relatively gentle slope, in which the raw materials with air flow have direct and counter contact. For this purpose, the kiln process was modeled and optimized using the equations of transfer phenomena, operational variables, and chemical reactions. Also investigated were primary and secondary reactions resulting from incomplete combustion. Results demonstrated that increasing excess air from 0–30% decreases exhaust gas concentration. Also, if the extra air is raised to 30%, the kiln performance efficiency and the combustion flame model do not show significant variations, and the CO mass fraction decreases.