10
turbulence at separator inlet. Connect oil separator drain line to a trap or pipe loop
seal.
5.2.6 Steam
Steam is required to heat and deaerated water. Thermodynamic laws determine the
quantity of steam necessary for deaeration. In order to accurately calculate the
required steam it is necessary to set up a heat balance. The steam consumed by a
deaerator consists of that needed to raise the temperature of incoming water to the
saturated temperature within the vessel, plus carrier steam utilized in vented
noncondensables. This quantity is reduced by the introduction of flash steam from high
temperature returns. Heat balance calculations should be made using the lowest
incoming water temperatures.
The following procedures may be used to calculate steam requirements: ‘A’ and ‘B’ are
approximations. ‘C’ is an exact method. Other established procedures are acceptable.
5.2.6.1 Definitions
Q – Total deaerated outlet capacity
(# / hr.)
Qm – Inlet water (under consideration)
(# / hr.)
Qf – Condensate (flashing) (# / hr.)
P – Steam pressure (psi)
T
1
– Steam temperature (saturated temperature at inlet pressure) (°F)
T
2
– Water temperature (°F)
Hf and Hfg – Enthalpy (at steam pressure, see any steam table)
5.2.6.2 Procedures
Sum all of the flows of required steam for inlet water heating and deduct any steam
flashed from hot condensate. This sum will be the maximum steam volume required by
the deaerator for the load in question. The procedure may be reversed and solved for
any amount of make-up required.
5.2.6.2.1 If the operating steam pressure is between 1 and 5 psig and if the maximum
combined inlet water temperature is below 100°F, the steam required will be one
seventh of the outlet flow.
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