Cogeneration Plant Upgrade from F9 to E11 and Eliminates Fouling,  Pressure Drop and gas turbine maintenance

THE CHALLENGE

• Heavy fouling required offline water washes every two months.
  
  
• Final filter pressure drop reached up to 480Pa. Instead of replacing the filters, which would require an unwanted shutdown, the plant had to derate the engine.
  
  
• Corrosion was detected in both the cold and the hot sections of the gas turbine.

The plant requested a solution that would improve their degradation issues, eliminate unwanted downtime, extend the final filter life to 3 years, and stabilize pressure drop.

THE SITE

The plant is located on the West Coast of Singapore, where it is challenged by salt-laden air and year-round humidity ranging from 70-90%. PM2.5 ranges from 50-70μg/m3, which is 130% greater than the national average.¹

The main sources of contaminants arise from the plant‘s industrial neighbors, including power producers and refineries. Additionally, every summer a large-scale haze caused by forest fires in Indonesia reaches Singapore. Pressure drop spikes, fouling, and corrosion are therefore prominent consequences under these challenging circumstances.

FILTRATION SOLUTION

The plant’s original filtration system was comprised of 500 M6 bag prefilters at the first stage and 500 F9 static final filters at the second stage.

Due to the harsh environment of the plant, an EPA filtration solution with hydrophobic, self-drainant, and low pressure drop properties was required to protect the turbine. Camfil performed a Life Cycle Cost Analysis (LCC) that showed which filter set would generate the most savings. The LCC showed that the plant would save approximately $1.56m USD every three years, per gas turbine, from fouling and pressure drop, with the following solution:

• A two-stage static system with Cam-Flo GT Hybrid F7 bag filters and CamGT 3V- 600 E11 compact final filters.

As a result, the plant decided to upgrade their filters with the recommended solution.

Benefits of the Camfil Solution • Improved fuel efficiency • Higher power output • Reduced maintenance requirements • Extended component life • Increased reliability • Safer operations • Reduced CO2 emissions per MWh

RESULTS

The operational efficiency of the gas turbines greatly improved with the CamGT installation, despite the challenging environment.

Result 1: The plant reported that they no longer experienced fouling. As a result,  the plant’s annual frequency of offline water washes went from six to zero with Camfil’s solution. According to ‘Impact of Enhanced GT Air Filtration on Power Output and Compressor Efficiency Degradation’ (2016)², Figure 1 shows the average compressor efficiency degradation due to the filter upgrade is generally expected to improve by around 1-2%, while the average power degradation is generally expected to improve by 4-5%. 

Figure 1. Recoverable performance degradation as a function of the filter class combination

Result 2: Pressure spikes were no longer an issue. Figure 2 shows that pressure drop was more stable between 200-230Pa after Camfil installation.    

Figure 2. Pressure drop before and after Camfil Installation

Result 3:  The plant reported that they no longer experienced engine corrosion.

The Value Rating classification system simplifies the filter selection process for gas turbine users in the Power Generation and Oil & Gas industries by helping them easily evaluate the efficiency and quality of primary air inlet filters. The Value Rating of a filter is a projection of the impact a final filter will have on a gas turbine’s performance in terms of power output, fuel consumption, and carbon emissions. A filter’s Value Rating can be calculated using a new online calculator, and requires four simple inputs that can be pulled from a filter’s test report. Try the calculator at www.thevaluerating.com .

Features of Camfil's solution

 

CamFlo GT Hybrid F7 bag filter Conical bag for improved airflow Maximum surface manufactured with the propriety Controlled Media Spacing method, used for high dust holding capacity Thick synthetic pre-filter layer for high mechanical strength and coalescing properties, suitable for humid environment A fine glass fiber layer to provide high efficiency with stable dP in high humidity Frames available in steel for maximum robustness, and plastic for incinerability

CamGT 3V-600 E11 compact final filter Vertical pleat with open hotmelt for improved drainage and low dP Patented double sealed construction and hydrophobic media eliminates the risk of dissolved contaminants or salts by-pass Patented aerodynamic grid to further reduce dP and increase strength Withstands wet burst pressure over 6250Pa Largest media area for longest life or higher airflows application