Oil-Free Hydrogen Compressor

The DOE is developing delivery technologies that will enable the introduction and long-term viability of hydrogen as an energy carrier for transportation and stationary power. To be successful, approaches must address hydrogen¿s relatively low volumetric energy density and its difficulties with respect to transportation, storage, and final delivery to the point of use. In particular, existing hydrogen compressor designs can not meet the need for a reliable, efficient and cost competitive transportation infrastructure. Therefore, this project will develop an oil-free bearing technology that will enable oil-free centrifugal hydrogen gas compressors to boost in-line pressures by approximately 700 psig and deliver 300 kg/min of hydrogen gas. In Phase I, a number of oil-free centrifugal compressor configurations were identified that could meet the stated boost pressure and flow requirements. However, the high operating speeds and sealing requirements indicated that very low power loss bearings and low leakage seals would be needed to make the compressor system viable. Therefore, Phase II will involve the design and fabrication of full-scale, oil-free compliant foil bearings. The bearings will be tested at design speeds of 50,000 to 60,000 rpm, while realistic loads are to be applied to the bearings. (The development of very low leakage seals and has been proposed under a separate program.) Commercial Applications and other Benefits as described by the awardee: The bearing technology developed for hydrogen compressors should allow higher efficiency natural gas pipeline compressors to be built and operated, making large-scale, hydrogen gas delivery viable. Today, almost 50 million horsepower is used to service natural gas pipeline compression needs; an estimated savings of 33,000 MW-hours of energy savings per year would be possible if advanced oil-free bearings and seals were employed.