COMPACT CRYOGENIC COOLING OF LIQUID MEDIADOWN TO –120℃ WITHOUT FREEZINGAND WITHOUT CONTAMINATION OF THE COOLANT

摘要

In the CUMULUS? FTC system controllable liquid media temperatures down to –120℃ isrnachieved by cooling with liquid nitrogen (LIN). Generally the liquid media is arnhydrocarbon or a mixture thereof with a melting point of more than 5℃ lower than therndesired process temperature. By separating the process of evaporation or boiling of the LINrnfrom the heat transfer between the coolant (nitrogen) and the process media, freezing isrnavoided in the system. The heat transfer is taking place in standardized plate heatrnexchangers, which makes the system design comparably compact and light. The result is arnpatented system with a high surface to area ratio and hence a low dead volume that gives arnfast reacting and accurate temperature control.