Compressor Selection for the Re-liquefaction System of Liquefied Ethylene Gas Carrier
TONG Zheng-ming, HU Dong-liang, HOU Peng, HE Jun-cheng
（ School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China）
Abstract: Ethylene production is an important criterion to measure the industrial level of a country but ethylene production locations are normally scattered unevenly and the supply and demand are not in the same place. As transportation of ethylene by traditional pipelines cannot meet the demands in every place, waterway has become one of the major ways for ethylene transportation and liquefied ethylene gas carrier is used because there are space limitations and cost requirements for the vessels to carry ethylene. Liquefied ethylene gas carrier should be equipped with re-liquefaction system to avoid the waste and the environmental pollution caused by evaporated ethylene gas. Compressor is a vital part of the system and its selection is very important. To attain the aim of a simple, efficient and energy-saving device, the compressor for the re-liquefaction system of ethylene gas carrier should be selected on the basis of the characteristics of the compressors and the results of accurate thermodynamic calculation for compressed stages, compressed pressures, exhaust temperatures, cylinder diameter, piston diameters, cylinder stroke volume as well as the actual situations onboard ethylene gas carrier.
Key words: ethylene gas carriers; re-liquefaction system; compressor; thermodynamic calculation; type selection