Flowserve Corp., a global provider of flow control products and services for the global infrastructure markets, has formed a joint venture with The Linde Group to commercialize and deploy ionic liquid compressor iKompressor natural gas and biogas refueling systems in Europe.
Called Flowserve Compression Systems GmbH, the joint venture plans to deliver at least 70 iKompressor refueling systems by 2009 to Germany, Austria, and neighboring European Union (EU) countries. The iKompressor systems are designed to reduce energy costs by up to 20% at low-inlet pressures, substantially reduce maintenance costs, and deliver high system reliability.
The demand for alternative fuels continues to increase. In order to meet customer needs, the iKompressor is designed to deliver the critical element to deliver reliable, safe service at compressed natural gas and biogas refueling systems.— Dr Aldo Belloni, a member of the Executive Board of Linde AG
Flowserve believes that iKompressor’s ionic compressor represents an advance in technology for multistage gas compression technology. The iKompressor’s design includes two new concepts: the use of proprietary ionic liquid as a liquid piston instead of a conventional fixed metal piston, and efficient gas compression at near isothermal conditions.
Linde has been working on the use of ionic compressors for hydrogen and natural gas for a number of years. Fixed metal piston compressors, used for pressures between 200 and 1,000 bar, have many moving parts, and the guides and bearings have to have good lubrication in order to prevent wear. For a fixed-piston compressor to be efficient for natural gas of hydrogen fuel, however, the gas-side space must be absolutely tight; otherwise, lubricant could get in and contaminate the gas. To avoid this problem, Linde developed the ionic compressor.
In contrast to ordinary molecular liquids, ionic liquids consist entirely of particles with negative and positive electric charges. The ionic liquid media developed by Linde are organic salts with melting points between below 100° C. Ionic liquids have no vapor pressure; the medium cannot mix with the ambient atmosphere provided it does not reach its decomposition temperature.
An ionic liquid compressor replaces the metal piston of a conventional compressor with a specially designed, nearly incompressible ionic liquid. The gas in the cylinder is compressed by the up-and-down motion of the liquid column, similar to the reciprocating motion of an ordinary piston. Because the ionic liquid does not mix with the gas, there is no need for seals and bearings in their compressor.
Use of liquid in place of solid pistons significantly reduces the number of moving parts and frictional losses contributing to energy efficiency and low wear and tear. Station owners, as a result, can experience at least a ten-fold increase in maintenance intervals—10,000 hours between scheduled maintenance versus 1,000 hours for conventional designs, according to the partners.
Further, the gas compression is performed at constant temperature using a water-cooled jacket around the compression cylinders. Gas compression at constant temperature (isothermal) is the most efficient thermodynamic compression cycle possible. Conventional reciprocating compressors operate on the efficient nearly isentropic compression cycle. This combined effect results is designed to use up to 20% less energy consumption at low-inlet pressure.
The joint venture will be headquartered adjacent to Flowserve (Austria) GmbH manufacturing facilities in Brunn am Gebirge, a suburb of Vienna, Austria. As part of the arrangement, Linde will supply the technology, ionic liquid, and ongoing applied research and development.
In Germany, natural gas vehicles are expected to increase to two million units by the year 2020, according to the International Energy Association.
Flowserve Corp. is a leading providers of fluid motion and control products and services. The Linde Group is a world leading gases and engineering company with more than 50,000 employees working in around 100 countries worldwide.
Mobility under high pressure, Linde Technology, January 2006