Van Air Systems PLD 8-14.5 User Manual
P/N 32-0310
June 2009
INSTALLATION, OPERATION AND MAINTENANCE INSTRUCTIONS
FOR
PIPE LINE DEHYDRATOR FOR NATURAL GAS
PLD8-14.5 thru PLD36-14.5
tm
WARNING
DO NOT REMOVE OR REPAIR ANY ITEM ON THIS VESSEL WHILE IT IS PRESSURIZED.
DO NOT OPERATE A LEAKING VESSEL. IMMEDIATELY TAKE VESSEL OUT OF SERVICE
AND NOTIFY YOUR CERTIFYING AUTHORITY. IF THERE IS A LEAK, INSPECT AND REPAIR OR REPLACE AS NECESSARY.
DO NOT OPERATE ABOVE MAXIMUM WORKING PRESSURE (MWP) AND OR MAXIMUM
OPERATING TEMPERATURE (DEGREES OF).
DO NOT WELD OR GRIND VESSEL. IT WILL NOT BE SAFE TO OPERATE.
DO NOT OPERATE IF VESSEL HAS BEEN DAMAGED BY FIRE. TAKE OUT OF SERVICE
IMMEDIATELY AND NOTIFY YOUR CERTIFYING AUTHORITY.
ANY DAMAGE TO VESSEL CAN MAKE IT UNSAFE. INSPECT OUTSIDE AND INSIDE OF
VESSEL REGULARLY FOR CORROSION AND DAMAGE (I.E., DENTS, GOUGES OR BULGES).
IF DAMAGED, TAKE OUT OF SERVICE IMMEDIATELY AND NOTIFY YOUR CERTIFYING
AUTHORITY.
PAGE 1
1.0 PURPOSE
A Pipeline Dehydrator removes the water vapor (humidity) present in the
gas stream. The process cleans and dries the gas as it flows through the
vessel which is filled with a special drying agent (desiccant). The
dehydrator operates automatically. There are no moving parts and no
external source of power is required.
"Wet" natural gas enters the lower portion of the dryer where liquid water
and solid particles are separated by gravity and fall to the bottom of the
vessel. The gas moves upward through the prebed and drying bed of
Van Gas desiccant tablets. The tablets attract and absorb moisture from
the gas as it flows through the desiccant bed. The tablets dissolve
gradually as they absorb the moisture and the liquid falls to the bottom of
the vessel. The liquid run off in the prebed creates an extended surface
area capable of removing additional moisture from the gas. This conserves the absorbent desiccant tablets. The "dry" natural gas flows
through the dryer outlet.
The solution of dissolved desiccant and water that falls into the claim
area at the bottom of the vessel must be drained regularly to prevent the
vessel from flooding. An automatic drain valve can be installed to
prevent the vessel from flooding.
2.0 INSTALLATION
2.1 LOCATION
The ability of a dehydrator to dry natural gas is dependent
on the correct location of the unit. Temperature and pressure are the keys to selecting the proper location.
IMPORTANT
ALWAYS PROCESS THE GAS THROUGH THE
DEHYDRATOR AT THE LOWEST TEMPERATURE AND THE HIGHEST PRESSURE.
INLET TEMPERATURE: Lower inlet gas temperatures will
result in lower moisture content at the dehydrator outlet.
Locate the dehydrator at the point where temperature is the
lowest.
CAUTION
The gas temperature should not exceed:
100°F for GASDRY PRIME
80°F for GASDRY PEAK
100°F for GASDRY MAX
MAXIMUM CAPACITIES - MSCFD
1,000 STANDARD CUBIC FEET PER DAY
MAXIMUM
MODEL
PLD8-14.5
PLD12-14.5
PLD16-14.5
PLD20-14.5
PLD24-14.5
PLD30-14.5
PLD36-14.5
PART
NO.
80-1477
80-1442
80-1483
80-1482
80-1484
80-1485
80-1486
WORKING
PRESSURE
1450 PSIG
1450 PSIG
1450 PSIG
1450 PSIG
1450 PSIG
1450 PSIG
1450 PSIG
100
PSIG
64
119
188
310
447
695
1191
750
PSIG
428
793
1255
2069
2983
4635
7943
AFTERCOOLING: If the gas being processed has been
compressed mechanically, an aftercooler, finned tubing or
extended run of piping will usually be necessary to reduce
the inlet gas temperature to the dehydrator.
OPERATING PRESSURE: More gas can be processed
through the dehydrator at higher pressures. Locate the
dehydrator at the highest practical pressure, but do not
exceed the maximum rated working pressure of the dehydrator. Refer to the capacity chart located below.
CAPACITY: The chart below indicates the maximum flow
rate through the dehydrator for a 24 HOUR period. To
calculate the capacity for a rate per minute just multiply the
MSCFD RATE (from chart ) by 0.6944 example:
A PLD12-14.5 operating at 100 PSIG has a maximum
MSCFD rate of 119. To figure the SCFM multiply 119
MSCFD x 0.6944 which equals 83 SCFM
NOTE: This is the MAXIMUM instantaneous flow that can
be processed through the dehydrator without deterioration of the drying performance.
1000
PSIG
567
1052
1666
2746
3958
6150
10539
1100
PSIG
623
1156
1830
3017
4348
6756
11578
1200
PSIG
679
1259
1994
3287
4738
7362
12616
1300
PSIG
735
1363
2158
3558
5128
7968
13655
1400
PSIG
791
1467
2322
3829
5518
8574
14694
1450
PSIG
819
1519
2404
3964
5714
8877
15213
PAGE 2
2.2 PIPING & ANCILLARY EQUIPMENT
2.3 INLET AND OUTLET PIPING
IMPORTANT
COMPLY WITH ALL FEDERAL, STATE, AND
LOCAL REGULATIONS CONCERNING INSTALLATION OF NATURAL GAS SYSTEMS.
COMPLIANCE WITH AND KNOWLEDGE OF
ALL REGULATIONS IS THE RESPONSIBILITY OF THE INSTALLER.
Make sure that the gas temperature is not over the maximum for the desiccant being used. If gas temperature is too
high, cool it prior to the dehydrator.
Mount the dehydrator on a level surface capable of supporting the weight of the vessel, such as a cement pad or
a skid.
Install a pressure relief valve in the up-stream
piping (relief valve not furnished). A relief valve
must be installed to conform with the ASME
Boiler and Presssure Vessel Codes, Section VII,
Division 1 UG-125, Paragraph (1) and OSHA
standards. Also comply with all applicable
Federal, State and Local codes.
Two shut-off valves should be installed (not furnished
with dehydrator)--one at dehydrator inlet and another at
dehydrator outlet. See Figure 2-A Recommended
Installation.
Connect the inlet piping and outlet piping as shown in
Figure 2-A.
NOTE
Inlet and outlet shut-off valves will make start-up
and addition of desiccant easier.
2.4 DRAIN VALVE
Install a drain valve (not furnished with dehydrator) in the
drain coupling at the bottom of the tower (except on
PLD8-14.5). A float/auto drain valve system is available.
Contact Van Gas for details.
2.5 AFTERFILTER
Van Gas "GF" Series Filters can be installed downstream
of the dehydrator to remove particulate contamination
from the natural gas. Contact Van Gas for details.
FIGURE 2-A RECOMMENDED INSTALLATION
PAGE 3
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