5.7　Cylinder Cooling

5.7.1　The type of cylinder cooling may be static-filled coolant systems，atmospheric thermosyphon coolant systems or forced-liquid coolant systems.Cylinder cooling shall be in accordance with 6.8.3.1 through 6.8.3.4 of API Std 618-2007.

5.7.2　Forced-liquid cylinder jacket coolant systems shall be provided when cylinders are operated while unloaded for extended periods of time，either the expected maximum discharge temperature is above 100℃or the adiabatic gas temperature rise is 85℃or greater，and the ambient temperature is 45℃or higher.

5.7.3　The cylinder cooling system provided shall be adequate to prevent gas condensation under all conditions including start-up in cold condiction.Coolant inlet temperature shall be at least 5℃above the inlet gas temperature.Coolant exit temperatures shall not be higher than 17℃above gas inlet temperature.In applications where it is known that the gas dew point is substantially below the gas inlet temperature and remains that way at all times during operation，a lower coolant inlet temperature may be considered as long as condensation is avoided.

5.7.4　If the circulating water conditions at site cannot meet the requirements of this Specification 5.7.3.A self-contained，closed jacket coolant system shall be furnished（refer to API Std 618-2007，Appendix G，Figure G-1 Plan D）.The cylinder jacket coolant system shall be in accordance with 6.8.3.5 of API Std 618.