|
Click on the cover to read the latest issue of PSB
Affiliate Links
|
VSDs deliver energy efficiencies01 January 2005The historic Glenfiddich whisky distillery in the Highlands of Scotland is saving energy and saving money thanks to an innovative water level control and pumping system critical to the water distillation processGlenfiddich was founded in 1886 by William Grant, and on Christmas day 1887 the first Glenfiddich spirit
trickled from the stills. Today Glenfiddich is the best-selling single malt Scotch whisky in the world - one in
every five bottles of single malt whisky sold in the world is a bottle of Glenfiddich.
In the distillation process, the ‘wash’ which is created from the fermentation of the malted barley is distilled in copper pots that exactly match the shape and size of the original stills bought over a century ago by William Grant. Continual heating gradually turns the alcohol to vapour, which rises through the narrowing neck of the still and is guided downwards through a water-cooled condenser.
At this stage the condensate contains about 21% alcohol, and the distillation process is repeated in smaller ‘spirit stills’. The vaporised alcohol is drawn off and condensed as before, with the final liquid now a legally bonded, taxable spirit.
Running and monitoring the distillation process is the responsibility of a ‘stillman’, and is a delicate operation where any mistake can ruin the whisky’s flavour. Only the fine middle cut, or ‘heart’ of the distillation is retained for maturation, which the stillman catches at the flick of a tap.
Crucial to the process, then, is the cooling of the condensate. The water for the cooling operation comes
from a storage dam, which is kept topped up by pumping from a nearby pond formed from the Glenfiddich river.
“We use two pumps to push the water up against gravity to the storage dam, ensuring we have a reliable water supply for the condensation process,” says Glenfiddich’s Derek Matheson. “Historically we had run the pumps at fixed speed, 24 hours a day, seven days a week, 365 days a year, but we began to wonder if we could increase efficiency without compromising supply.”
Looking around for systems which would provide this efficiency boost, Glenfiddich highlighted an ultrasonic
level measurement and water distribution system from Siemens Process Instruments - the EnviroRanger ERS500.
Using non-contacting ultrasonic technology and patented echo processing techniques, the EnviroRanger accurately monitors and controls liquid levels, providing control outputs to variable speed drives for more efficient pump operation, and eliminating the need for any further discrete control equipment.
When Matheson asked about suitable variable speed drives for the pumps to work in conjunction with EnviroRanger, MicroMaster drives were recommended. Two Siemens MicroMaster drives were therefore installed and linked via profibus to the EnviroRanger system, which provides the required control signals
based on the water level in the storage dam. A key advantage of the system is that the pumps no longer need to be driven at a fixed speed. Since the power used by a pump is proportional to the cube of the speed, a nominal reduction in speed can give a much larger percentage reduction in energy usage.
There are secondary benefits as well. Because MicroMaster drives ramp up the pumps to the required speed, and then ramp them back down at programmed rates for starting and stopping, the motors are not hit by the huge initial torque that comes with direct-on-line starting, so reducing maintenance and lengthening the operating lifespan.
“With the new control system in place, we are accurately controlling the pumps so that water delivery precisely matches demand,” says Matheson. “That means we are making significant energy savings.” Contact Details and Archive...Related Articles...Most Viewed Articles... |
|