15 October 2011

Salt producer saves 1.6 gigawatt-hours a year on single fan

Salt Union in the UK uses dryers to produce a million tonnes of salt every year. One of its dryers processes a coarse, granular product used in applications such as dishwashers.

However, much of the power it used was being wasted. The fan sucked air through the dryer at a rate controlled by a damper in the pipeline. During normal operation, this damper was 95% closed, so most of the fan's energy was being used to suck the air through the narrow constriction.

The fan was badly oversized because the dryer was previously used to process vacuum salt crystals, which are much smaller than the spherical, 2-3 mm diameter particles in granular salt. The fine crystals created a far bigger pressure drop across the dryer than today's coarse product. The challenge was to find a way of cutting the energy wasted by the dryer because of the oversized fan.

An energy survey by the local ABB Drives Alliance partner was carried out to determine what potential savings could be achieved. The solution was to replace the single oversized fan with a smaller version equipped with speed control.

The original fan motor was rated at 337 kW, but the calculations carried out by the ABB Drives Alliance partner showed that 132 kW should be enough to create the draft needed by the dryer.

The energy saving on the fan equates to over 1.6 GWh a year, a cut of over 60%. For an investment of just £20,000 , Salt Union is saving over 100,000 pounds a year.

At Salt Union, energy-saving initiatives are not confined to the process. Even the small amount of waste heat now produced by ABB's AC drive is being put to work warming up the switch room in winter.

If you would like further information, please contact us or phone 0113 2631509