Demand for cryogenic services has b

Demand for cryogenic services has been strong since the middle of the twentieth century. Cryogenics refers to the science of materials at extremely low temperatures.Cryogenics has a wide range of application in physics, chemistry, medicine, biology,engineering, and industry. The term cryogenic is derived from the Greek words cryo, meaning“very cold,” and genic meaning “to generate.” There is no clear standard for what qualifies as cryogenic temperatures. But this book proposes a cryogenic temperature range of
50°C to
196°C, based on the British Standard (BS 6364) for cryogenic services. Another cryogenic valve standard, Manufacturers Standardization Society of Valve and Fitting MSS SP 134, sets the range at
100°C to
255°C.Thus, cryogenic temperature ranges vary from one standard to another and from one project to another. Temperatures between
29°C and
46°C are considered merely low temperatures.Fig. 2.2 summarizes the process of LNG extraction from natural gas at cryogenictemperatures.