EGR compressor: a one-stage turbo-compressor with an asynchronous motor and a variable frequency drive.? ?Exhaust Gas Recirculation (EGR) is a method to significantly reduce the formation of Nitrogen Oxides (NOx) in marine diesel engines. By using this technology, vessels are able to meet with the IMO NOx Tier III standard emission limits applying to the North American and United States Caribbean Sea as well as any new NOx Emission Control Areas (NECA). The EGR compressor is a one-stage turbo-compressor with oil lubricated bearings, direct driven with an asynchronous motor and a variable frequency drive. The design features the unique flow optimization mechanism, utilizing inlet guide vanes to optimize efficiency for a given motor rating. The core compressor features an impeller with backward leaning blades angled according to regulation and milled from a solid, forged piece of duplex stainless steel with an optimal weight/strength ratio. All parts in contact with the medium are made of corrosion resistant steel. The compressor is equipped with a contact free carbon floating ring sealing to ensure that no exhaust gas can escape from the compressor casing.