Cement rotary kiln combustion “The simulation of various primary air cases and nozzle geometries allow us an optimal design of our burner-nozzle systems. By comparing the different cases, we were able to optimize our PYROJET burner in regards of thorough fuel burnout, low NOx emissions and optimum clinker quality. Enrag not only provided us with the CFD simulation results based on jointly developed parameters, but also provided us with very good support in the evaluation of the results. Those optimizations solely by operational trials would not have been possible in this (short) period of time.”

Alex KnochKHD Humboldt Wedag

To investigate the impact of different burner configurations on the formation of NOx

emissions and the quality of the produced clinker in a rotary cement kiln, a coupled gas-solid simulation was performed.

To describe the gas phase, a commercial CFD software was used. The combustion process was modeled with lagrangian coal particles and volatilization. Heat transfer was considered through conduction, convection and radiation. For the clinker phase a tailor-made code was developed. Bed height and residence time of the solid material as well as chemical reactions including reaction heat were accoun-ted for.

As a result of the coupled simulation, the temperature distribution and the maximum flame temperature in the kiln as well as the point of ignition were depicted. Additionally, the gas species fractions (CO, O2, NOx) were investigated in terms of different burner configurations. By means of the clinker model, the composition at the kiln outlet and the formation of the clinker species within the kiln were examined.

STARTING POSITION:

METHODS:

RESULTS:

Temperature

Solid Clinker Species

Oxygen fraction

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