Safety Considerations for Large Insulated Casings for Liquid-Hydrogen Plants

Abstract

The recent installation of large hydrogen-liquefaction facilities testifies to the increasing importance of this type of plant. The problems of safety associated with the design of a casing enclosing hydrogen process equipment at cryogenic temperatures are somewhat more complex than those of a typical oxygen-nitrogen plant, and several additional factors must be considered. Flammable gas and liquid are being processed and can leak into the insulation space. It is therefore necessary to keep air out of the insulation and provide a safe means for venting process fluids from the casing in the event of a large leak, A blanketing atmosphere such as nitrogen or hydrogen must be kept in the casing, the gas selected depending on the process operating temperatures. This paper will discuss these factors in relation to large casings as encountered in recent hydrogen plant installations. However, similar problems and design approach apply to smaller powder or vacuum-insulated casings.