Gas turbine protection key for industry investment
Optimising air quality for oil and gas applications is a critical factor in protecting your investment, says expert
Optimising air quality for oil and gas applications is a critical factor in protecting your investment, says Stephen Hiner, chief engineer at Clarcor Industrial Air.
A gas turbine air inlet filter prolongs turbine life and reduces maintenance. The filter’s optimum configuration is a balance between equipment protection, cost, required maintenance and pressure drop. Temperature, salt levels, moisture and dust size and type (dry or sticky) can all affect system performance.
Sodium in salt will combine with sulphur in the fuel within the hot section of the turbine to cause Type
I and Type II accelerated corrosion. The mean time between failures in these conditions is highly dependent
on this corrosion level which is directly related to the protection that is provided to prevent salt entering
the gas turbine inlet.
Dust particles greater than two microns can cause erosion, affect turbine efficiency, and damage machinery.
Coarse filter media captures this larger dust, but not finer dust which can stick to machine parts and
change operating aerodynamics; reducing gas turbine efficiency and increasing operational costs.
Fine filter media with high filtering efficiency is required to capture the smaller dust particles and reverse this negative impact on the gas turbine and your business. Where both dust and salt are present, different filtration stages will afford better protection.
However, by adding a filtration stage for each contaminant, pressure loss across the system is increased. A larger filter house will help countermand this but space, cost and performance required need to be assessed.
When maintenance, high availability, high performance and long machine life are important, the ROI of a more comprehensive filtration system can make sound business sense.
Latest media technology and clever aerodynamics can provide compact filtration solutions that perform well at elevated flow rates and provide equivalent performance to traditional low flow rate solutions.
These help where space is a premium and reduce the compromise between cost and performance; lowering the cost of adding greater system protection. Moisture can swell captured contaminants in the filter system, increasing pressure loss.
For sites within 12 miles of water, the installation of coalescers is recommended. These remove moisture and liquid phase corrosives to help protect downstream filters and the gas turbine, but coalescing filters can require frequent maintenance in dusty environments which reduces the availability of the system and can consequently result in high costs.
If they are left out, however, fine water droplets will mix with contaminants. Water will also combine with captured dust to form mud – increasing the system pressure loss and potentially tripping the turbine. But if moisture is allowed to wash through, contaminants will also pass through and cause increased
fouling and corrosion of the gas turbine.
To counter these conflicting issues, a new coalescer – the TS1000 with patented media configuration
- was developed which allows sand and dust to pass through while still providing highly effective moisture
removal from the air stream.
This has been shown to significantly extend periods between clogging, require less monitoring and less maintenance. The media is easily cleaned with a water hose, reducing maintenance time and cost.
About the author:
Stephen Hiner is chief engineer at Clarcor and sits on a number of International Standards Committees for
Gas Turbine Inlet Filtration.