After successful tests using deepwell pumps to handle LNG at -163 deg C, Hamworthy Svanehøj A/S is making available to the gas carrier market its full range of deepwell pumps covering capacities from 50 m3/h to 700 m3/h.

Hamworthy Svanehøj deepwell pumps are already well established for handling LEG (ethylene) and LPG cargoes. Following technical assessment of a version modified for handling LNG as well, in 2006 Hamworthy Svanehøj A/S signed its first contract involving the use of deepwell pumps for LNG at -163 deg C. Final cryogenic testing has recently demonstrated the success of the modifications.

Hamworthy Svanehøj A/S will supply the deepwell pumps in early 2008 for installation in a 7,700m3 LNG/LEG/LPG carrier being built by Polish yard Remontowa for Rotterdam-based shipping company Anthony Veder. This unique vessel will be an LNG tanker for regional distribution, and will also be able to transport other gases as well, among them liquefied petroleum gas (LPG) and petrochemical gases including ethylene. The pumps will be fitted with normal explosion-proof motors powered by frequency converters, enabling them to develop 210 mlc LNG and the typical 120 mlc LEG/LPG at a rated flow of 450 m3/h for both duties.

After the pumps had been modified to lower the normal design temperature of -104 deg C for LEG down to -163 deg C for LNG, a series of cryogenic tests using liquefied nitrogen as pump medium were carried out. The test temperature with nitrogen at approximately 4 bar pressure was -185 deg C, well below the required -163 deg C.

In close co-operation with the client, the final cryogenic test was carried out in August 2007 to demonstrate some main objectives. One of these was to demonstrate that the selected material modifications of some elements were satisfactory, and the selected clearances between the static parts and the rotating parts of the pump were correct for the specified temperature range of -163 deg C to +45 deg C. Another objective was to demonstrate that the standard sealing and bearing arrangement will not be affected by the lower service temperature.

“Based on this successful test Hamworthy Svanehøj A/S is now ready to enter other specific projects in this segment as the use and distribution of LNG in smaller quantities is rapidly increasing,” said Hans Høyer Jensen, responsible for sales and marketing of Hamworthy Svanehøj deepwell pumps.