Spirax Sarco helped Northumbrian Water to halve the energy it uses to raise steam at an anaerobic digestion plant. And the work was so successful that the utility company now plans to apply the same approach at a new facility at Howdon.
The energy-saving project centred on solving a problem with a brace of boilers at Bran Sands where a low-water alarm would come into operation, even when there was plenty of water in the system. Low-water alarms made the boilers cut out, reducing the time that the equipment was in action.
“The issue slowed the process down,” explained Frank Errington, works coordinator at Bran Sands. “We’d lose energy as the boilers were on and off constantly and were cooling down during the downtime.”
The water company called in Spirax Sarco engineers who quickly spotted that the level probes and controllers were not suitable for the application.
Spirax Sarco supplied two LP30 self-monitoring water level probes for each boiler, along with LC3050 level controllers. Rewiring and a new control panel completed the new low-water alarm system.
The plant was also experiencing an increasing problem issue with false alarms in its high-water control systems, although they didn’t cause the same downtime and energy losses as the low-level alarms. Here, Spirax Sarco also replaced the existing products with its own LP31 probes.
Finally, the utility company opted for a Spirax Sarco service agreement to keep the boilers working properly in future.
“Both boilers are now available most of the time and we’re experiencing stable operations,” said Errington. “The energy savings equate to about 50% of the energy needed for raising steam.”
Northumbrian has now asked Spirax Sarco to apply the same boiler controls at its new anaerobic digester facility in Howdon, which is currently under construction.