A hospital power plant in Alberta, Canada had a reverse osmosis (RO) water piping failure that caused city water to feed directly into its boilers. This hardness excursion led to extensive scaling on the boiler heat transfer surfaces, and one of the boilers experienced a tube rupture.
Veolia initially recommended a temporary dosage increase of the existing treatment, Solus AP26, which is part of Veolia's latest boiler scale control and internal treatment technology. The Solus AP product is an advanced deposit control chemistry designed to ensure clean heat transfer surfaces, even under stressed conditions such as feedwater hardness upsets.
Solus AP26 contains caustic, and the higher dosage caused increased alkalinity levels. Due to the concern for caustic attack in the boilers, Veolia sought an improved treatment.
A switch to Solus AP25 was suggested as it has a higher polymer concentration and a lower caustic contribution. The goal was to continue improving boiler heat transfer efficiency by removing hardness deposits while avoiding abrasive acid cleaning on the fouled boiler internal surfaces. After this program change, the boiler inspection pictures showed significant deposit removal from the steam drums and boiler tubes (Figure 1.)
Resultado
The Veolia team analyzed steam production and natural gas consumption data from the plant operational data to evaluate the boiler steam-to-fuel efficiency that resulted from removing hardness deposits. Calculations compared fuel energy input relative to the steam energy output.
To establish a baseline comparison of boiler efficiency improvement, this evaluation compared the period following the application of Solus AP25 to the same time period in the previous year, where hardness scaling had taken place. The boilers saw a combined 15% efficiency improvement by switching the internal treatment chemistry to Solus AP25 and removing the hardness deposits.
This efficiency improvement resulted in a total savings of $79,715 CAD. Additionally, 3,029 Tons of eCO2 emissions were avoided at the plant by reducing fuel burning due to the improvement in heat transfer once the insulating deposit was removed.
Desde su puesta en servicio, esta WRF ha sido reconocida por la National Association of Clean Water Agencies (NACWA) con premios al Máximo Rendimiento por su continua excelencia en el tratamiento de aguas residuales.
