Filtration of Gas Turbine Intake Air in Offshore Installations: The Gap Between Test Standards and Actual Operating Conditions

Gas turbine performance deterioration caused by fouling in the compressor section is a well known phenomenon in offshore installations. This performance deterioration not only increases fuel consumption and emissions but also has a severe economic impact when it reduces oil and gas production. Because fouling in the compressor section is commonly caused by intake air contamination, gas turbines offshore have air inlet filtration systems in order to limit the amount of ingested contaminants. Many different filtration systems from various suppliers are in operation offshore. Manufacturers supply documentation for their filtration system based on several international standards, and it can be challenging for the operator to make a direct comparison of different filtration systems. The comparison is further complicated by the fact that the characteristic offshore challenges related to salt and moisture in the intake air are not adequately covered in international standards, and these challenges are handled and documented differently among the manufacturers. This paper analyzes the challenges related to choosing the best filter solution for an offshore gas turbine installation based on data from offshore sites in the North Sea. The relevance of test requirements in applicable international standards and available supplier documentation is evaluated based on actual operating conditions offshore. Deviations among international test standard requirements, available manufacturer documentation, and actual operating conditions offshore are identified, and improved test requirements are suggested. In addition, this paper addresses the long-term effects of filter contamination and methods for intake filter monitoring based on data from offshore sites in the North Sea.