Abstract
AbstractDepth filters used in multistage filter systems adeptly clean the intake air of gas turbines, preventing damage and increasing performance. However, estimation of their service life is based on empirical data and/or standardized testing procedures, e.g., ISO 16890. By applying standardized synthetic test dusts at constant reference humidity, these testing procedures do not reflect application‐typical loading conditions. Based on a direct comparison with field data, the influence of temporary exposure to high relative humidity on differential pressure and particle deposit structure is investigated. The results indicate that simulating humidity variations of the ambient atmosphere during filter tests leads to particle deposits, which more accurately reflect the actual behavior during operation.
Highlights
Gas turbines are highly susceptible to damage when they are not adequately protected from particle exposure
To more accurately reproduce real-world operating conditions in filter tests, a test aerosol with specific particle size distribution (PSD) was developed, which reproduces the fine fraction of the ambient aerosol, seen in the second and third filter stage of turbine cleaning systems
Two sets of experiments were conducted with this test aerosol: one included loading of filters with soluble KCl at low Relative humidity (RH) of 30 %, the other included additional periodical exposure to RH between 85 % and 90 %, simulating natural variations in RH in the ambient air
Summary
Gas turbines are highly susceptible to damage when they are not adequately protected from particle exposure. Several common synthetic test dusts, differentiated by chemical and physical properties, such as test dust L2 from ISO 15957, are used to determine dust holding capacities at defined Dp, e.g., 200 Pa or 300 Pa depending on the separation efficiency of the filter according to ISO 16890 [6] These test dusts usually contain particle fractions and substances that differ greatly from typical ambient aerosols with respect to chemical composition and PSD. Gupta et al and Joubert et al loaded HEPA filters with submicron and micron hygroscopic NaCl particles and nonhygroscopic Al2O3 at RH up to 90 % and 100 %, respectively, up to cake formation [7,8,9] They found that a higher operating RH correlates with an increase in the filter dust holding capacity. A comparison to analyzed field data allows an assessment of the results and shows discrepancies between current testing methods and the actual operating behavior in the field, as well as the potential of filter testing which considers relevant RH variations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
