Taylor-Wharton High Capacity GST Storage Tanks - Manual (Page 17)

17
OPERATION
These instructions are for experienced operators. Before operating the storage tank become
thoroughly familiar with the safety precautions in this manual and in reference publications.
Make certain all applicable provisions set forth in the Installation section have been followed
before placing a tank in operation. Study the Flow Diagram, Tank Elevation and End Views on
the applicable General Arrangement Drawing located in the back of this manual and the
Functional Description section of this manual. Know the location and function of all tank
components.
PURGE PROCEDURE
Before placing a tank in service, determine the level of purity in the pressure vessel. If pressure
vessel contents purity is unacceptable, perform a product purge to reduce contaminants. The
following procedure is recommended for most applications:
1.
Attach the liquid purge product source to tank FILL CONNECTION. Product delivery
pressure should be approximately 100 psig (6.9 bar/690 kPa).
CAUTION:
A positive pressure must always be maintained in the tank during the purge
procedure to prevent drawing atmospheric contaminants back into the tank.
2.
Close all valves except VAPOR & LIQUID PHASE ISOLATION VALVES, and
PRESSURE BUILDING ISOLATION VALVES.
3.
Open TANK BLOWDOWN VALVE and vent inner vessel to 5 psig (0.34 bar/34 kPa) as
indicated on the tank PRESSURE GAUGE, INNER VESSEL. If not supplied with the tank
this PRESSURE GAUGE, INNER VESSEL must be installed by the Customer. Close
TANK BLOWDOWN VALVE.
4.
Open BOTTOM FILL VALVE slightly to allow liquid to flow slowly into bottom of tank.
Flow must be gradual enough to allow the liquid to vaporize in the bottom fill line and
PRESSURE BUILDING COIL so the pressure builds up in the inner vessel. Momentarily
open TOP FILL VALVE to flood the exposed section of line, then close valve.
5.
When tank PRESSURE GAUGE, INNER VESSEL indicates maximum desired purge
pressure, close the liquid supply source. Close PRESSURE BUILDING ISOLATION
VALVE.
6.
Cautiously drain liquid from the tank by opening the AUXILIARY LIQUID VALVE if
provided or through the FILL LINE DRAIN VALVE. The valve should be opened slowly
to avoid splashing of liquid. When vapor appears from the valve, the liquid has been
drained from the tank.
7.
Close AUXILIARY LIQUID VALVE or FILL LINE DRAIN VALVE opened in step 6.
8.
Tanks with factory supplied LIQUID LEVEL GAUGE: - After liquid has drained from the
tank, close VAPOR & LIQUILD PHASE ISOLATION VALVES. The EQUALIZATION