60 ARTICLE / MAKALE Microns 0,001 0,01 0,1 10 100 1000 -1 (Log scale) Scaning electron Optical Visible microscope microscope naked eye Test 1 aerosols ◄- SAE Fine Dust 1 -► ◄◄ Atomized Nacı l► ◄◄ SAE Coarse Dust 1 ►► DOPTest ◄ Smog ► ◄ Mold ►► Spores ◄ Aqueous ► Salts ◄-Dieseı soot -1 Bacteria ◄ uman ► Relative Hair size of Metal common ◄ ► ◄- Virus --...► ►► ◄◄ Mist ►► materials lons ◄- Catbon Black - -Pollen :t Lint -- ◄ Atomic - Tobaoco Smoke ►,◄◄ Coaı Dust --- BeachSand 1 -- ► Radii --1 - Colloidal silica -► -- Milled Flqur Figure 1. Relative dust/particle sizes. Source : Donaldson Company ine. Corrosion is caused where particles, chemicals, or vapours in the air react with a turbine blade's metal properties and cause damage to the b F l o a u d l e in s g . is the build-up of particles on the downstream side of the compressor blades, which reduces the efficiency of the turbine system as well as increasing the turbine's heat rate (and thus fuel consumption). Plugged cooling passages on !he turbine blades are another problem that filtration can solve. Turbine blades can get extremely hol, which isn't surprising since power generation is achieved using a combination of fuel and high-pressure air. To help cool the turbine, blades are designed with small air passages. Without proper air filtration to the turbine, fıne particulates can collect in these cooling passages, contributing to higher temperatures and potential damage to hol section components. Although most turbines are equipped with sensors so the system will shut down if temperatures get dangerously high, the life of these components can be shortened if !his is an ongoing problem. ENERJi & KOJENERASYON DÜNYASI TYPES OF CONTAMİNANT Many types of air contaminant !hat plague turbine systems are invisible to the eye. For example, hydrocarbon emissions from internal combustion engines are in the sub-micron range and are among the smallest contaminants, but their 'sticky' nature makes them particularly troublesome. Other common contaminants that affect turbines include dust, moisture/tog, frost and smoke. Smoke and hydrocarbons in heavy industrial areas and in some agricultural areas-where farmers burn sugar cane tor example-smoke can be a significant fıltration challenge tor inlet air filters. Smoke particles are very small and can be sticky. Similarly, where power plants are located in industrial or dense urban areas, the presence of hydrocarbon particles in the air is more common, due to engine exhaust or burning fossil fuels. There can also be situations where exceptionally high levels of hydrocarbons resul! in filtration challenges. Extreme cases are usually attributable to unique circumstances at a particular site. For example, a power planı operator customer in New York has a turbine inlet system located next to a railroad switching track. Diesel locomotives sometimes park w i thin 100 metres of an inlet air filler, so the exhaust from idling locomotives is drawn into the air filters. in another example, a filtration challenge was presented at a site in China where large amounts of coal and oil were being burned nearby for residential and industrial heating. lf air filters being used do not have sufficient efficiency on small particles, these partic l es will pass through the fılters and stick to the turbine blades. This is the primary cause of touling. Wild enough build-up of these particles on the blades, the aerodynamic air flow pattern across !he blades is altered, which causes effıciency problems in the turbine. On the other hand, because of the sticky nature of some of these particles, they can plug the pores of the fılters, resulting in p S r e e le s c s t u i re drop problems. ng !he correct fılters in these environments can be a challenge. However, 100 % synthetic media filters with very smooth fıbres have been designed to provide high efficiency while maintaining low pressure drop, even in applications with a high hydrocarbon content.
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