Alto Garda (AG) Power in Italy manages a cogeneration power plant with high availability requirements (7900 hours/year) where they supply electricity and steam to paper mills. Additional requirements include supplying district heating for the town of Riva del Garda, including offices, schools, kindergartens, etc.
In an effort to increase the performance of the 44 MW gas turbines, Camfil Power Systems was asked to optimize their existing filtration system. The aim of the collaboration was to decrease the total filtration system pressure drop (dP) to achieve the following:
• More power output for the same fuel consumption,
• Extended filter lifetime, as well as less time and effort required for filter replacement,
• Higher engine protection and availability.
The sites are located in coastal to land based conditions, where air quality can be challenging. Relative humidity is moderate to high with an average of 73%, as well as significant precipitation and fog/mist.
ORIGINAL FILTER CONFIGURATION
The original installation has a 2-stage system design consisting of pleated pre-filters with G4 efficiency, and final filters with F9 efficiency.
This system presents the following drawbacks:
• High dP spikes, especially in high humidity, rain, or fog conditions result in:
o Pre-filter replacement every 4 months,
• Final filter replacement every year.
• Low filtration efficiency and no drainage capabilities cause engine degradation.
• Rigid design limits the choice of products for replacement.
Camfil conducted several site surveys to recommend the optimal air filter solution to enhance the performance of the engines. The shortest possible installation time during scheduled maintenance was a fundamental prerequisite.
Based on environmental and operational conditions, the OEM and AG Power decided to upgrade the existing system to a 2-stage static filter solution. The system consists of two air tight filter banks holding the Cam-Flo GT Hybrid F7 pocket air filters and the CamGT 3V-600 E10 final EPA air filters.
This system has the following advantages:
• Low and stable dP, even under wet and humid conditions:
o pre-filter life time expectation > 1 year
• final filter EPA class lifetime expectation > 3 years,
• Greater engine protection due to EPA efficiency and efficient water drainage,
• Flexible design.
The graph below compares typical pressure drop performance of the previous installation and the Camfil gas turbine filtration solution. Before the upgrade, pressure drop averaged 750 Pa (3"), and multiple shutdowns for pre-filter replacement were required throughout the year.
The Camfil solution, two years later, continues to maintain a low and stable pressure drop at an average of 375 Pa (1.5" w.g.). As a result, pre-filter replacement decreased to once per year during the plant's annual outage, without a final filter change yet.
Due to pressure drop savings, as well as fouling reduction from the higher efficiency solution, AG Power will have saved approximately 650 000 Sm3 on fuel consumption.
Additionally, they were able to reduce their CO2 emissions by approximately 1100 tons per year.