Simulating the Impact of Oxygen Enrichment in a Cement Rotary Kiln Using Advanced Computational Methods

Abstract

This work presents the simulation of a rotary kiln used to produce cement clinker. The effort uses an original approach to kiln operation modeling. Thus, the moving cement clinker is accurately simulated, including exothermal reactions into the clicker and advanced heat transfer correlations. The simulation includes the normal operation of a cement kiln, using coal in an air-fired configuration. The results show the flame characteristics, fluid flow, clinker and refractory characteristics. Two types of coal are employed, one with medium-volatile and one with low-volatile content, with significant differences noted in the kiln operation. A specific goal of this effort is to study the impact of oxygen enrichment on the kiln operation. For this purpose, oxygen is lanced into the kiln at a location between the load and the main burner, and the impact of oxygen enrichment on the kiln operation is assessed. Different oxygen injection schemes are also studied. Thus, varying the angle of the oxygen lance enables to handle various problems as reducing conditions, overheating in the burning zone or refractory wall. It is concluded that oxygen has a beneficial role in the fuel combustion characteristics, and its impact on refractory temperature and the clinker is negligible, in conditions of increased productivity and overall efficiency. The paper presents the impact of dust insufflation into the kiln, such as reduced temperature profile, resulting in a less stable combustion process. The work shows the beneficial influence of oxygen enrichment on kiln operation in the presence of dust, leading to an increase in the amount of dust capable of being insufflated into the kiln. The paper presents the impact of dust insufflation into the kiln, such as reduced temperature profile, resulting in a less stable combustion process. The work shows the beneficial influence of oxygen enrichment on kiln operation in the presence of dust, leading to an increase in the amount of dust capable of being insufflated into the kiln.