Study on nitrogen barrier protection of an airend oil-free compressor bearings in H2 compression

Abstract

The oil free compressors were specially designed for air compression. The National Research and Development Institute for Gas Turbines COMOTI gained a great deal of experience in producing/designing certified oil injection screw compressors for the natural gas field and for several years it has been focusing its research on the use of “dry” (oil-free) compressors in natural gas compression and more recently in hydrogen compression. Working with an explosive gas, one of an idea was to use a nitrogen barrier in oil bearing sealing, which are open source of gases in the atmosphere for such compressors. Worldwide, on-site nitrogen generators have been developed for a purity range of 95…99.5%, and that nitrogen can be supplied in any environment conditions. The present paper will address nitrogen flow with low percentage of oxygen for bearing sealing at the working pressure, the nitrogen consumption, ideas for H2 re-injection and the influence over the global efficiency of the process. Due to the Energy Strategy worldwide, and the studies regarding production, transport and storage of hydrogen in natural gas network, COMOTI has involved researches in developing such possibilities and to express a point of view in existing research in the newly created industry.