Cryogenic Containers Transfer

The development of foam-insulated cryogenic containment piping was undertaken to achieve lower costs and to improve reliability. It was estimated that the foam thermal insulation would increase the low-temperature refrigeration load caused by heat transfer from the surrounding soil by an additional 49.7 kW/km (80 kW/mi) for a 3500-MVA cable system. This increase can be partially offset by... 

PRESSURIZED COOL-DOWN OF A CRYOGENIC LIQUID TRANSFER SYSTEM CONTAINING VERTICAL SECTIONS... 

Drawings and specifications for standard transfer connections for cryogenic liquids are contained in CGA V-6, Standard Cryogenic Liquid Transfer Connections [11]. Drawings and specifications for carbon dioxide liquid and vapor transfer connections are contained in CGA V-6.1, Standard Carbon Dioxide Transfer Connections [12]. 

AV-8 Characteristics and Safe Handling of Cryogenic Liquid and Gaseous Oxygen, Subjects covered include characteristics, uses, containers, transfer systems and procedures, safe handling. 

Special equipment must be used to contain, transfer, and store cryogenic liquids. This equipment is specially designed to withstand the extreme differences in temperature and rapid temperature changes experienced when working with these liquids. 

A special-purpose, yet very useful, valve concept is represented by the terminal valve in Fig. 7.36. This valve, which can be opened or closed at the very end of a transfer line, allows a cryogenic container to be filled without possible contamination from air or moisture. Another type of valve, the helium-operated valve (not shown), has been very useful in the transfer of liquid hydrogen. This valve can be readily operated by remote control and opened and closed by helium gas. A magnetically operated valve has recently been developed specifically for use in small liquid helium transfer lines. This all-metal valve is opened by an energized coil and closes by gravity and pressure differential forces. 

Section 7.17 of the text develops a mathematical description of the heat transfer into a vapor-shielded cryogenic container. This results in an expression, Eq. (7.31), that relates the temperature difference between the vapor shield and the inner container to the temperature difference between the ambient and the inner container in terms of two dimensionless ratios, namely, the ratio of the sensible to the latent heat of the gas and the ratio of the inside overall heat transfer coefficient to that of the outside overall heat transfer coefficient. If the mass flow rate through the shield is reduced to zero, the expression reduces to the form shown in Eq. (7.32). Provide the missing steps to show that this is true. 

Three methods are commonly used to transfer a cryogen from the storage vessel. These are self-pressurization of the container, external gas pressurization, and mechanical... 

Equation (5.2) indicates that the time vapor is advected downwind will increase as zt (height of vapor containment box) increases, as this increases the time to fill the vapor box. This additional time allows for the effects of decreasing rates of conductive heat transfer from the dike floor for cryogenic materials, or decreasing convective mass transfer for materials with boiling points that are higher than ambient temperatures, to take effect. 

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