ABB implemented a complete solution for Holcim, driven by digital technologies that aided in the gathering of information followed by modeling of the process to identify the best possible way of running the plant at all times to achieve all objectives.
One key component of this solution was variable speed drives (VSDs) and the other model predictive control (MPC). Both of these components, coming together by the use of advanced digital technologies, was key to enabling optimized energy usage at the Holcim plant.
The large fans that draw air through the kiln, precalciner, mills and filters into the exhaust stack, supported by smaller fans to push air into the grate cooler, require precise airflow adjustment and control. These adjustments need to account for a variety of factors, including atmospheric conditions, process conditions and ventilation. This is where VSDs installed at the plant played a key role in driving energy efficiency; and, depending on the required flow rate, helped achieve power savings of up to 70% when compared with fixed-speed motors.
At the Holcim plant, ABB used a multidrive system, which offered all the benefits of VSD plus a range of additional benefits including reduced cabling requirements, energy-savings from motor-to-motor braking, reduced space requirement and elimination of low voltage distribution required for single drives.