Alcan benefits from submerisble pump switch

Manchester, UK -  Alcan is operating five Mono Merlin pumps at its coal-fired power station in Lynemouth, Northumberland to overcome problems previously encountered with submersible pumps. The plant serves the nearby Alcan smelting plant and has several nuisance water sumps across the site from which water containing coal dust is pumped into the main drains which then flows via gravity to the treatment plant.

Alcan purchased five Merlin pumps from Wyko Electro Mechanical Services, which carries out maintenance work at the site and is a supplier of Mono equipment. As well as being used to pump the nuisance water contaminated with coal dust at 6.3m3/h with a 2 meter suction lift, one of the pumps is also pumping from a sump containing water contaminated with oil.

The presence of coal particles in the water had caused frequent blockages of the submersible pumps and in addition abrasive wear was increasing the maintenance and downtime to every two months. The Mono pumps have now been in operation for 18 months without any problems.

The location of the submersible pumps at the bottom of the sump, in amongst the nuisance water, means they were often dirty and difficult for the maintenance staff to reach on their frequent and costly break down visits. The pumps needed to be lifted out of the sump requiring the use of the associated lifting gear, which had to meet stringent health and safety compliance.

Maintenance personnel also had to enter the sumps to relocate the pumps once they were repaired. Alcan urgently required more efficient and reliable equipment and so wanted to move away from submersible pumps, therefore surface-mounted progressing cavity pumps were selected with a proven track record of reliable service in the coal industry.

According to Mono, its progressing cavity pump uses a hard rotor turning within a soft resilient rubber stator. The interference fit gives better seal and wear characteristics ensuring that abrasive particles are easily handled with low wear rates. A suction lift of up to 8.5 meters also means deep sumps can be easily pumped out, without the need for submersible equipment.