Counteracting ring formation in rotary kilns

Abstract

Avoiding the formation of rings in rotary kilns is an issue of primary concern to the cement production industry. We developed a numerical combustion model that revealed that in our case study rings are typically formed in zones of maximal radiative heat transfer. This local overheating causes an overproduction of the liquid phase of the granular material, which tends to stick to the oven's wall and to form rings. To counteract for this phenomenon, we propose to increase the amount of secondary air injected to cool the oven. Experimental validation at the plant has confirmed that our solution is indeed effective. For the first time in years, the kiln has been operating without unscheduled shut-downs, resulting in hugely important cost savings.

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

“…We subsequently compare results for the streamlines and the temperature with results in the literature. We in particular compare with earlier results obtained using commercial software published in [10].…”

“…In the current state of development, IB-Raptor does not allow the simulation of reactive flow. To validate the reactive flow computations, we therefore compare with our previous results in [10].…”

“…In this work, we study the non-premixed turbulent combustion in the full-scale cement rotary kiln that we considered earlier in [10]. In this earlier work, simulations were performed using a commercial CFD package.…”

Predictive models and operation guidance system for iron ore pellet induration in traveling grate–rotary kiln process

“…In this study, oxidation of magnetite is neglected considering a weak oxidative atmosphere in the kiln, this assumption leads to a small error on temperature profile since oxidation degree of acid iron ore in the kiln using pulverized coal is generally less than 5%. Ring formation is partly attributed to high wall temperature (Pisaroni et al, 2012) and has been simply formulated in Peng et al (2009). However, the essence of ring formation is still a controversy and its thickness distribution along kiln axis is hard to simulate, this phenomenon is also not considered.…”

"Hot Rotary Kiln Deformability for Cement Plant, Experimentation, and Numerical Simulation"

“…We divide the kiln into three upstream parts, the middle parts is downstream (Pisaroni, 2012). To conduct a comparative study of the first four meters of the kiln.…”