ACS inverter drives from ABB improve cement plant clinker cooling
For clinker quality, clinker cooling is best carried out by progressively controlling the cooling process. The most common way to control the cooling fans and the exhaust fan’s speed, and hence ensure efficient and precise cooling, is to use AC drives such as the ACS880 Series from ABB UK.
Hot clinker supplied by the kiln enters the clinker cooler. The clinker travels on the clinker cooler bed where it is cooled by several clinker cooling fans. The cooling air is blown through the cooler bed. Exhaust air is extracted by an exhaust air fan.
AC drives for accurate control of cooling air
The cooler requires a continuously changing air flow in order to provide proper cooling of the clinker. By using AC drives, the amount of cooling air can be exactly controlled. This means that electrical energy is not wasted, as opposed to damper control of the cooler fans.
When the air pressure at the kiln outlet is to be kept within tight tolerances, without compromising efficient cooling, the exhaust air fan and the clinker cooler fans need to be operated in close cooperation. The use of AC drives to control the speed of both clinker cooler and exhaust air fans guarantees a fast and precise regulation of cooling air and an easy connection to the cement plant’s automation system.
AC drives also enable soft start of the fans, which minimizes mechanical stress of the fans, pipes and other mechanical equipment. Through soft start, the supply network can be sized with a low starting current, thus reducing the low voltage switchgear, transformer and cabling costs.
Many benefits of using ACS variable speed drives include:
− Substantial energy savings through optimal control of cooling air
− Enables removal of mechanical control devices, e.g. damper control (plates) of fans – which require regular maintenance due to harsh environment
− Soft start of fan motors− Flying start of fan motors without high starting torques or high starting current peaks thanks to DTC
− Power loss ride-through, i.e. in case of power failure in the supply network, the AC drive can utilize the energy from the fan‘s rotating inertia in order to keep the control electronics operational during the power failure
− Jump-over of critical frequencies
− High power factor
− Easy connection to the cement plant‘s automation system via various fieldbus adapters
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