Taylor-Wharton High Capacity GST Storage Tanks - Manual (Page 20)

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3.
Open supply source liquid delivery valve.
4.
Fully open tank BOTTOM FILL VALVE, PRESSURE BUILDING ISOLATION
VALVES start tank fill. Open tank TOP FILL VALVE one turn. Adjust the two FILL
VALVES as required to maintain normal tank operating pressure as shown on tag attached
to tank PRESSURE GAUGE, INNER VESSEL.
NOTE: Filling through the BOTTOM FILL VALVE will increase tank pressure
since gas in the vapor space is compressed, whereas filling through the TOP
FILL VALVE decreases tank pressure since gas in the ullage space is cooled
and re-liquefied.
5.
Open tank FULL TRYCOCK VALVE when tank LIQUID LEVEL GAUGE indicates 3/4
full.
6.
When liquid spurts from tank FULL TRYCOCK VALVE, close supply source delivery
valve to stop fill. Close tank BOTTOM FILL VALVE and FULL TRYCOCK VALVE.
7.
When residual liquid in the fill hose vaporizes, close tank TOP FILL VALVE.
CAUTION: To avoid injury, do not touch fill hose or connections with bare hands.
During filling, these parts are cooled to extremely low temperatures.
8.
Open FILL LINE DRAIN VALVE to relieve fill hose pressure. Close FILL LINE DRAIN
VALVE.
9.
When pressure is released disconnect fill hose.
NORMAL OPERATION
During normal operation, tank pressure forces product through the siphon withdrawal line and the
PRODUCT SUPPLY VALVE to an external vaporizer that feeds the user's pipeline. To
compensate for lowering of tank pressure as product is withdrawn, the PRESSURE BUILDING
REGULATOR allows a regulated amount of liquid to flow to the PRESSURE BUILDING COIL.
Vaporized liquid is returned to the tank to provide the driving force for uninterrupted pipeline
withdrawal. During periods when the withdrawal rate is low and tank pressure rises above the set
point of BACK PRESSURE REGULATOR, the economizer circuit becomes operational. Liquid
withdrawal is interrupted and gas flows through the BACK PRESSURE REGULATOR to the
vaporizer thereby supplying the pipeline with gas that would otherwise be vented to the
atmosphere.
To prepare the tank for normal product withdrawal, open the following valves:
PRESSURE BUILDING ISOLATION VALVES,
VAPOR PHASE ISOLATION and LIQUID PHASE ISOLATION VALVES,