Vaporizer Design Considerations

DOE-HDBK-1132-99

3.2.4

Vaporizer Design Considerations . Although various kinds of vaporizers are

available in the market, ambient vaporizers are the most commonly used. The

vaporizer selection should be based on careful evaluation of the following

factors:

ambient conditions,

material properties,

structural loading criteria, and

location (i.e., free versus obstructed airflow).

Service Piping . The temperature of the gas outlet is an important factor in

3.2.5

selecting pipe materials for nitrogen service piping. The vaporizers are flow

rated based on an industry standard of about 10 to 20 EF below the ambient

conditions: the lesser the flow, the warmer the outlet gas. Items that affect the

heat transfer of the units are the position of the sun, ambient temperature, airflow

around the units, and relative humidity. Due to the low outlet temperature of the

vaporizer, the liquid nitrogen piping to the pressure regulator is normally low-

temperature piping.

3.2.6

HVAC. HVAC equipment should be sized to satisfy the building heating and

cooling requirements and to meet the general equipment design and selection

criteria contained in ASHRAE handbooks.

3.3

Pumps. Positive displacement pumps should be considered for use in the following

situations; high pressure and low flow, high-viscosity fluids, suspended solids, self-

priming, two-phase-flow, and constant flow at variable system pressure.

3.4

Valves.

Gate valves are unsuitable for throttling and should be used in the full open or

closed position.

Globe valves should be used primarily for throttling service only unless system

flow reverses, and the globe valve serves as a stop valve.

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