Cement Production Using A 300kWel Plasma System - An Experimental Study Of The Thermal Behavior In A Pilot-Scale Rotary Kiln

Other conference contribution, 2025

Rotary kilns are crucial in cement production, where efficient heat transfer and precise temperature control significantly impact performance. Rotary kilns are also strongly linked to fossil emissions and a fuel exchange for less carbon-intensive alternatives, such as electrification, is essential. Therefore, this study focuses on the ongoing investigation of a pilot-scale experimental kiln, 2700 mm in length, 710 mm in outer diameter, and 580 mm in inner diameter, using a 300 kW CO2-based plasma system as a high-temperature heat source for a passing bed material. The work aims to understand the kiln's temperature distribution, heat transfer mechanisms, and radiative characteristics under various operational conditions and bed materials.

In the current phase, temperature measurements were conducted using thermocouples at multiple axial and radial positions to capture temperature gradients within the kiln wall. Initial tests, performed with the kiln in an empty configuration, included plasma operation in horizontal and tilted positions, revealing a noticeable rise in temperature with the tilted setup. These results provide preliminary insights into heating rates and heat loads. Future work, currently in progress, will involve trials with bed material and varied operational parameters. A multi-point gas probe with four thermocouples will measure gas temperature profiles, while suction pyrometers will assess flue gas outlet temperatures. Inner and outer wall temperatures will be monitored using an IR camera, and radiative intensity and flux will be measured with radiometers at multiple kiln ports. These investigations will help to understand thermal conditions, radiative characteristics, and heat transfer mechanisms.

The final presentation will include analyzed data from completed measurement campaigns, providing a detailed understanding of the rotary kiln's heat transfer characteristics and temperature control. This work highlights the potential of high-power plasma systems as sustainable heating solutions in cement production.