Efficient steam raising

Spirax Sarco has helped Northumbrian Water halve the energy it uses to raise steam at its Bran Sands anaerobic digestion plant.

The work has been so successful that the utility company now plans to work with Spirax Sarco and apply the same approach in its new plant at Howdon.

The energy-saving project centred on solving an issue with two boilers at Bran Sands where a low-water alarm would come into operation, even though there was plenty of water in the system. Low-water alarms made the boilers cut out.

Frank Errington, works coordinator, says: "We'd lose energy as the boilers were on and off constantly and were cooling down during the downtime." Spirax Sarco engineers found that existing level probes and controllers were not suitable for the task and supplied two LP30 selfmonitoring water level probes for each boiler, along with LC3050 level controllers. Rewiring and a new control panel completed the alarm system.

Bran Sands was also experiencing problems with false alarms in its high-water control systems, although they didn't cause the same downtime and energy losses as the low-level false alarms.

Spirax Sarco replaced the high-water probes with its own LP31 probes.

The utility company opted for a Spirax Sarco service agreement to keep the boilers working properly in future.

Errington says: "Both boilers are now available most of the time and we're experiencing stable operations. Energy savings equate to about 50% of the energy needed for raising steam."