8/13/2019 Alarm & Trip Setting List (11) http://slidepdf.com/reader/full/alarm-trip-setting-list-11 1/40 PT. Brown & Root Indonesia Doc. No. 74-IOM-PS-1201 Rev. 6A Project TLNG Author’s Org. KJP KJP Doc. No. S-074-1283-001 Date 26 Sep, 06 KJP Job Code J-3400-20-0000 Sheet 1 of 40 X Core Non-core Lifecycle Code A For Information For Review For Approval X Released As-Built Rev. Date Page Description Prep’d Chk’d App’d BP App’d 5A 24Feb06 all For Approval T.Bessho M.Ditto M.Ditto 6A 26 Sep 06 4-5, 9-28, 30, 40 For Release T.Bessho Y.Kakutani Y.Kakutani 3.8 MTPA TRAIN CAPACITY Operation Manual for Refrigerant Storage and Transfer BPMIGAS TANGGUH LNGBP Berau Ltd. _ _ _ _ _ | | | | _ _ _ _ _ I N D R A 2 6 -S E P -2 0 0 6
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4. Initial Start-up Procedure..........................................................................................................8 4.1 General ........................................................................................................................................8 4.2 Defrosting ....................................................................................................................................9 4.3 Initial Liquid Filling .................................................................................................................10 4.3.1 PROPANE R EFRIGERANT STORAGE TANK (074-TK-1002A/B) ................................................ 10
4.3.2 ETHANE R EFRIGERANT STORAGE TANK (074-TK-1001)......................................................... 13 4.4 Transfer of Refrigerant into LNG Train................................................................................19 4.4.1 MAKE-UP OF ETHANE R EFRIGERANT TO LNG TRAIN.............................................................. 19 4.4.2 MAKE-UP OF PROPANE R EFRIGERANT TO LNG TRAIN ............................................................ 19
5. Normal Start-up Procedure .....................................................................................................21 5.1 General ......................................................................................................................................21 5.2 Start-up Procedure after Scheduled Shut-down....................................................................21 5.3 Start-up Procedure after Emergency Shutdown ...................................................................21
6.2 Process Control .........................................................................................................................24 6.2.1 LIQUID LEVEL OF STORAGE TANKS ......................................................................................... 24 6.2.2 PROPANE R EFRIGERANT STORAGE TANK PRESSURE................................................................ 24 6.2.3 ETHANE R EFRIGERANT STORAGE TANK PRESSURE................................................................. 24
7. Normal Shutdown.....................................................................................................................25 7.1 General ......................................................................................................................................25 7.2 Shut-down of Make-up Operation ..........................................................................................25 7.3 Long Period Shut-down ...........................................................................................................25
8. Emergency Shut-down – Emergengy Depressuring Procedure............................................26 8.1 General ......................................................................................................................................26 8.2 Emergency Shut-Down (ESD - EDP) System.........................................................................26 8.2.1 074-US-2000A PROPANE R EFRIGERANT STORAGE TANK ISOLATION AND DEPRESSURIZATION26 8.2.2 074-US-2100 ETHANE R EFRIGERANT STORAGEISOLATION AND DEPRESSURIZATION............ 27 8.2.3 074-US-2000A PROPANE R EFRIGERANT STORAGER EPRESSURIZATION................................. 27 8.2.4 074-US-2100 ETHANE R EFRIGERANT STORAGER EPRESSURIZATION...................................... 28 8.3 Utility Failure..........................................................................................................................28 8.3.1 ELECTRIC POWER FAILURE ..................................................................................................... 28 8.3.2 UTILITY WATER FAILURE ........................................................................................................ 28 8.3.3 I NSTRUMENT AIR FAILURE ...................................................................................................... 29
9. Safety Procedure.......................................................................................................................29 9.1 General ......................................................................................................................................29 9.2 Hazardous Material..................................................................................................................30
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BP Berau Ltd. Tangguh LNG Project
1. INTRODUCTION
The Refrigerant Make-up and Storage Unit (Unit 074) consist of ethane and propane refrigerant
storage tanks bullets and transfer charge pumps. This unit provides offsite storage of propane and
ethane refrigerant to charge the refrigerant systems in the process trains when the normal make-upfrom Refrigerant Preparation Unit (Unit 041/042 ) is either unavailable or insufficient.
This storage is common for two process trains and is intended primarily to supply start-up refrigerant
for the propane and MR (Mixed Refrigerant) circuits in Refrigeration Unit (Unit 051/052).
Nitrogen, methane, ethane and propane refrigerants are normally supplied from connections within
the LNG process train. Liquid ethane and propane refrigerants are produced in Unit 041/042 in
quantities in excess of that needed for normal make-up. The excess refrigerant is used to charge the
two propane and one ethane refrigerant storage tanks bullets, and re-inject to LNG.
2. DESIGN BASIS
When LNG train system is operating, the ethane and propane refrigerant make-up are produced and
supplied from the dDeethanizer and the dDepropanizer, respectively.
The ethane and propane refrigerant Make-up and Storage (Unit 074) is provided to support the
following operating functions:
- Storage
- Initial Make-up
- Charging
- Rundown
- Drainage
Unit 074 consists of the following major equipment:
- Ethane Bullet Refrigerant Storage Tank – 074-TK-1001
- Ethane Charge Refrigerant Transfer Pump – 074-P-1001
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3. PROCESS DESCRIPTION
Following are descriptions for the operating functions provided in Unit 074
3.1 Storage
Ethane Refrigerant Storage Tank (074-TK-1001) and Propane Refrigerant Storage Tanks
(074-TK-1002A/B) provide refrigerant storage facilities for initial charge for two (2) LNG trains, for
rundown of refrigerant from the Refrigerant Preparation Unit (Unit- 041/042), for draining of
refrigerant from Refrigeration Unit (Unit-051/052), and charging refrigerant to Unit 051/052.
Propane is stored in two identical bullets tanks 074-TK-1002A/B, which are filled simultaneously, at
ambient temperature and saturation pressure. The total propane storage capacity is sufficient to
provide refrigerant inventory required for two (2) LNG trains. Propane Refrigerant Storage Tanks
(074-TK-1002A/B) are not insulated.
Ethane is stored in a single bullet tank 074-TK-1001 at approximately minus 31oC temperature and
25 kg/cm2G saturation pressure. This saturation pressure allows reinjection of boil-off gas into LNG
product, after it is cooled through the LPG Reinjection Cooler (041/042-E-1012). The boil off gas of
approximately 190 kg/h (0.1wt% boil off) is generated due to outside heat leak into system and
vapor displacement. The total ethane storage capacity is sufficient to provide refrigerant inventory
required for two (2) LNG trains. The ethane storage system including 074-TK-1001 is insulated for
operation at sub-ambient temperature.
3.2 Initial Make-up
Initial propane make-up storage to the bullets storage tanks is provided by outside source and willhave to be transported to site as ship cargo. A potential supplier for propane is the Bontang LNG
facility. Imported propane is transported from a ship berthed at LNG jetty to Propane
Refrigerant Storage Tank (074-TK-1002A/B) using temporary pump, LNG circulation line
and temporary piping. (For details of initial propane make-up, see commissioning manual)
The imported propane composition shall be as follows;
Ethane (C2) 0.3 mol% maximum
Propane (C3) 99.2mol% minimum
Butane (C4) 0.5 mol% maximum
Pentanes and heavier 0.0 mol%
H2O 1 ppm (w)
Mercury 10 Ng/Sm3 (Hg Removal Vessel Outlet Spec)
Ethane will be produced insitu. Prior to the introduction of propane initially or after returning the
storage tanks bullets from maintenance, the storage bullet tanks shall be dried and inerted with
nitrogen and then dried with defrost gas. (See commissioning manual for details).
To facilitate loading of propane refrigerant in the storage tanks bullets, tank truck connection is
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BP Berau Ltd. Tangguh LNG Project
Ethane will be produced within LNG train area. The initial ethane (liquid) is charged is from the
Deethanizer Reflux Drum (D-041-D-1002) to Ethane Refrigerant Storage Tank (074-TK-1001)
using Deethanizer Reflux Pump (041-P-1002). after the introduction of Before charging ethane
liquid, Ethane Refrigerant Storage Tank (074-TK-1001) shall be pressurized with ethane
vapor from Deethanizer Reflux Drum (041-D-1002) in order to avoid low temperature
excursion in Ethane Refrigerant Storage Tank (074-TK-1001). (See Section 4.3.2)feed gas into
the LNG Train. Prior to the introduction of ethane initially or after returning the storage tank bullet
from maintenance, the storage tank bullet tank shall be dried and inerted with nitrogen and then
dried with defrost gas. (See commissioning manual for details).
Warning;
- When introducing ethane into a warm tank, care should be taken to avoid over pressuring due
to the total vaporization of the liquid ethane or over stressing the tank due to rapid localized
cooling.
After nitrogen or defrost gas in Ethane Refrigerant Storage Tank (074-TK-1001) is
replaced by ethane vapor from Deethanizer Reflux Drum (041-D-1002), liquid ethane
shall be introduced to the storage tank to avoid low temperature excursion of the storage
tank.
3.2.1 Startup Mode
Before starting the operation of the LNG train, propane and ethane are charged into Unit 051/052 for
preparation of propane and mixed (MR) refrigerants.
Propane is pumped by Propane Refrigerant Transfer Pump (074-P-1002) to the Propane
Accumulator (051/052-D-1005) in Unit 051/052.
Similarly ethane is pumped by Ethane Refrigerant Transfer Pump (074-P-1001) to the HP MR
Separator (051/052-D-1010) in Unit 051/052.
3.2.2 Shutdown Mode
When a shutdown of LNG train for an extended period and when maintenance of the propane
refrigerant circuit is required, a shutdown mode operation is carried out to create space in thePropane Refrigerant Storage Tanks (074-TK-1002A/B) to accommodate propane drained from
the propane refrigerant circuit. This operation mode is to allow the inventory in Propane
Refrigerant Storage Tanks (074-TK-1002A/B) reduce by the normal recharging of propane
refrigerant to the propane circuit without the normal recharging operation. This operating mode
continues until there is adequate space in Propane Refrigerant Storage Tanks (074-TK-1002A/B)
to accept the Unit 051/052 propane refrigerant.
There is no shutdown mode charging operation for ethane as it can not be separated from mixed
refrigerant. Liquid ethane of 372 m3 is normally stored in the ethane Ethane Refrigerant Storage
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3.3 Rundown
When refrigerant inventory in Propane Refrigerant Storage Tanks (074-TK-1002A/B) and
Ethane Refrigerant Storage Tank (074-TK-1001) is reduced, refrigerant is rundown from Unit
041/042 to make up the storage capacity.
Depropanizer Reflux Pump (041/042-P-1003A/B) transfers propane make-up liquid from
Depropanizer Reflux Drum (041/042-D-1003) to Propane Refrigerant Storage Tanks
(074-TK-1002A/B).
Deethanizer Reflux Pump (041/042-P-1002A/B) transfers ethane make-up liquid from the
Deethanizer Reflux Drum (041/042D-1002) to Ethane Refrigerant Storage Tank
(074-TK-1001).
3.4 Draining
Propane liquid should be drained from propane refrigerant circuit and the LNG train when extended
shutdown or maintenance is required. The propane refrigerant is drained into the Propane Transfer
Drum (051/052-D-1006) and pumped to Propane Refrigerant Storage Tanks (074-TK-1002A/B)
by the Propane Transfer Pump (051/052-P-1001).
Prior to this draining operation, shutdown mode operation should be carried out as described in 3.2.2.
3.5 Boil-Off Gas
Boil Off Gas in the Refrigeration Storage System is generated due to ambient heat leak into thesystem, vapors (within the system) displaced by liquids received and vapors generated during
rundown/charge pump operation. Ethane vapor (boil-off gas) is sent to LPG reinjection into the LNG
product. Propane vapor venting is not normally required. Any excess vapors above those normally
anticipated are flared. When all LNG trains are down, Refrigerant Storage vapors are flared.
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4.2 Defrosting
It is essential that all pipe work, storage tanks bullets and other equipment be free of water before
introducing hydrocarbons. This can be achieved using defrost gas from Unit 031/032 and venting the
gas from Unit 074 to the Dry Gas Flare.
(1) Introduce the defrost gas into propane and ethane lines into from the discharge lines of the
Depropanizer Reflux Pumps (041-P-1003A/B) and Deethanizer Reflux Pumps (041-P-1002A/B)
in Unit 041/042. The Defrost Gas is generated in Defrost Gas Heater (031-E-1004).
a. Only one section/tank shall be defrosted at a time to ensure maximum defrost gas.
b. Care should be taken that all block valves are properly aligned.
(2) Wet vent gas from the storage tanks bullets is routed to the dry flare system.
a. For propane rundown linei. Purge rundown line through 074-PF-1003-4”.1001
ii.Then through line 074-PF-1009-4”.
b. For Propane Refrigerant Storage Tank 074-TK-1002A
i. To dry the tank bottom opening the manual block and globe valves in 074-PF-1301-2”,which is connected to pump suction line. line.
ii. Dry the remaining tank by opening 074-PV-1212A
c. For Propane Refrigerant Storage Tank 074-TK-1002B
i. To dry the tank bottom opening the manual block and globe valves in 074-PF-1301-2”,
which is connected to pump suction line.ii. Dry the remaining tank by opening 074-PV-1212B
d. For Propane Refrigerant Transfer Pump 074-P-1002
i. Open suction line (074-PF-1004) block valve
ii. Open pump vent line (074-PF-1711) block valve, to route defrost gas through the suctionline and pump to the dry flare. Note that the pump shall not be rotated during defrost
operation because the pump rotation destroy the bearings.
e. For ethane rundown line
i. Purge rundown line through 074-EF-1001
e.f. For Ethane Refrigerant Storage Tank 074-TK-1001
i. To dry the tank bottom opening the manual block and globe valves in 074-EF-1301-2”,
which is connected to pump suction line.
ii. Dry the remaining tank by opening 074-PV-1212B1202B
f.g. For Ethane Refrigerant Transfer Pump 074-P-1001
i. Open suction line (074-EF-1003) block valve
ii. Open pump vent line (074-EF-1711) block valve, to route defrost gas through the suctionline and pump to the dry flare. Note that the pump shall not be rotated during defrost
operation because the pump rotation destroy the bearings.
(3) Allow the defrosting to continue until the effluent gas from the storage tank bullet reaches to less
ship loading flow rate based on the actual loading line layout, initial set pressure of
Propane Storage Tank on shore, and the operating pressure of ship storage tank).
Shipping pump shutoff pressure shall be checked and provide the protection system, ifthe existing line design pressure is lower than the shipping pump shut-off pressure.
(1) After inerting and drying Propane Refrigerant Storage Tanks (074-TK-1002A/B), propane
liquid from an external supplier a supply ship berthed at LNG jetty is charged into the tank
using a temporary pump via 071-GL-1502, 090-GL-1505, temporary piping, 090-PF-1501
and 074-PF-1001. using the 4” block valve on 074-P-1002 suction line. For this operation,
LNG circulation line (071-GL-1502, 090-GL-1505) is used as propane liquid transfer line.
In order to avoid a low temperature excursion during the initial charge, defrost gas at circa. 3.5
kg/cm2
G is used to pad the tank. (For details, refer to commissioning manual)
(2) Place tank pressure controller 074-PIC-1212A/B in the auto mode with an initial set point of
11.0 kg/cm2G, if ship tank operating temperature is ambient. . After the initial fill, the
074-PIC-1212 A/B can be raised to minimize propane losses. If ship tank operating pressure
is atmosphere, 074-PIC-1212 A/B shall be set at slightly higher than atmospheric pressure
(0.2 kg/cm2G) to prevent back flow from flare line.
(3) Displaced vapors are vented to the dry flare via tank pressure control valves
074-PV-1212A/B.
(54) After filling the tanks bullets sufficiently to fill the downstream, the lines and pump wells can be filled up slowly using the liquid head. (The seal chamber needs to be vented. Reference
Propane Refrigerant Transfer Pump (074-P-1002) pump vendor’s manual for requirements.)
(5) The remaining large amount of propane in loading line shall be drained out to dry flare
gradually. Propane loading line shall provide drain lines at all low points.
Note: After LNG train start-up, propane is sent from Depropanizer Reflux Drum
(041-D-1003) to Propane Refrigerant Storage Tank (074-TK-1002A/B) via propane
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(1) Ensure LPG re-injection cooler inlet ESD valve (041-USVE-2260) in close
position. Confirmed by field operator locally as the valve position is close.
(2) Ensure that control valve 041-PV-1212A on Deethanizer Reflux Drum overhead
line to LPG Re-injection Cooler (041-E-1012) and its bypass valve are in close
position. Field operator shall ensure that the above valves are in close position
locally. The excess ethane vapor is discharged to dry flare through
041-PV-1212B.
(3) Keep control valve 041-FV-1010 on C3 liquid re-injection line from
Depropanizer Reflux Pump (041-P-1003 A/B) and its bypass valve in close
position. Field operator shall ensure that the above valves are in correct position
locally. Excess on-spec. C3 products shall be sent to Propane Refrigerant Tanks
(074-TK-10002 A/B).
(4) Close the manual globe valve on the C4 liquid product line to LPG Re-injectionCooler (041-E-1012). Field operator shall visually check that the globe valve is
closed completely. All C4 products from Butane Recycle Pump (041-P-1005 A/B)
shall be submitted to MCHE (041-E-1001) as butane recycle.
(5) Put a spectacle blind installed on the check valve by-pass line of 41-EF-1014-1
1/2” in open position. And then open the two 1” gate valves on the check valve
by-pass line. Field operator shall make sure that the by-pass valves are in open
position locally.
(6) Check the line up from top of Deethanizer Reflux Drum to Ethane Refrigerant
Storage Tank through Ethane refrigerant vapor line (090-EF-1501-11/2”).
The flow direction of ethane gas introduction for initial start-up operation is
opposite to the normal flow direction. Field operator shall ensure that all
relevant valve position is correct.
(7) Open 074-USVE-2050 (Ethane vapor line from Ethane Refrigerant Storage
Tank in normal operation.). Field operator shall ensure that 074-USVE-2050 is
in open position locally.
(8) Fully open 074-PV-1202A installed on the vapor line from Ethane Refrigerant
Storage Tank to introduce ethane gas to Ethane Refrigerant Storage Tank.
(The gas flow direction is reverse in normal operation.) Field operator shall
ensure that the valve position should be fully open..(9) Ensure that 074-USVE-2020 on suction line of Ethane Refrigerant Transfer
Pump (074-P-1001) and 074-PV-1201 on the ethane liquid inlet line to Ethane
Refrigerant Storage are still in close position during pressurization of Ethane
Refrigerant Storage Tank.
(10) Slowly introduce ethane gas to Ethane Refrigerant Storage Tank through
041-PV-1212A by closing 041-PV-1212B gradually. Monitor the Ethane
Refrigerant Storage Tank pressure by 074-PIC-1202. Monitor pressure on
074-PG-9202 at pump suction in order to ensure that the pump suction valve
and suction ESDV-2020 are not leaked.
(11) Lighter components in Defrost gas shall be purged out to dry flare from the top
of a temporary spool on the Storage Tank (installed in place of
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and saturation pressure. Propane Refrigerant Transfer Pump (074-P-1002) is designed to
accommodate such changes in holding pressure and storage volume (level).
Similarly, ethane is pumped by Ethane Refrigerant Transfer Pump (074-P-1001) to HP MR
Separator (051/052-D-1010) is carried out under the supervision and control of the MCR utilizing
051/052-FIC-2480. The MCR operator adjusts the quantity of ethane liquid transfer by adjusting
the set point of 051/052-FIC-2480. (See Unit 051/052041 Operating Manual Section XXXXXX
8.4.1 for further details)
(2) Shutdown Mode
There is no shutdown mode charging operation for propane refrigerant.
There is no shutdown mode charging operation for ethane refrigerant.
6.1.2.2 Rundown
Rundown operation is carried out to supplement the refrigerant in the refrigerant storage
tanks bullets.
(1) Propane Rundown
Propane product is pumped by Depropanizer Reflux Pump (041/042-P-1003A/B) on flow
control (041/042-FIC-1011) from Unit 041/042 into Propane Refrigerant Storage Tank
(074-TK-1002A/B) via 041-PF-1011, 090-PF-1501 and 074-PF-1001. Part of vapor displaced by
the liquid rundown is absorbed by the subcooled stored liquid. Thus increasing the operating
temperature due to the absorption but this temperature rise is very small. Remaining vapor raises
the storage pressure. If tank pressure controller (074-PIC-1212A/B) is set at 15.8 5 kg/cm2g,
there should be no venting required.
(2) Ethane Rundown
Ethane product is pumped by Deethanizer Reflux Pump (041/042-P-1002A/B) on flow control
(041/042-FIC-1007) from Unit 041/042 to Ethane Refrigerant Storage Tank (074-TK-1001) via
041-EF-1007, 041-EF-1009, 090-EF-1502, 074-EF-1001 and 074-EF-1501. During initial
start-up, cooldown of the rundown line and storage tank bullet is required. The vapors generated by
the cool-down and normal heat leak to the system, and vapors displaced by the rundown liquid are
relieved to the flare via 074-PV-1202B or to one or the other LPG Reinjection Cooler(041/042-E-1012) by 074-PV-1202A. 074-PIC-1202 set point is 25.3 kg/cm
2g.
Warning:
Before introducing liquid ethane to Ethane Refrigerant Storage Tank (074-TK-1001), the
tank shall be pressurized up to 25kg/cm2G with ethane vapor in order to avoid low
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7. NORMAL SHUTDOWN
7.1 General
This section covers the normal shut-down procedure for Unit 074.
There are two types of shut-down to be considered.
(1) Shut-down of Make-up Operation
(2) Long Period Shut-down
7.2 Shut-down of Make-up Operation
The procedures of shut-down of Refrigerant Make-up and Storage Unit are as follows:
(1) Gradually decrease the make-up flow rate to LNG Train by closing the control valves (051/052-
FV-2580 for propane and 051/052-FV-2480 for ethane) by the MCR operator. These valves are
closed fully. The pumps are maintained under the minimum flow operation by the flow controllers(074-FIC-1011 and 074-FIC-1001) at discharge of the pumps.
(2) Stop the Propane Refrigerant Transfer Pump (074-P-1002) after 051/052- FV-2580 has been
closed and Ethane Refrigerant Transfer Pump (074-P-1001) after 051/052-FV-2480 has been
closed.
(3) Block in the hand control valves and flow control valves mentioned above.
Note : Ethane Refrigerant Transfer Pump (074-P-1001) and Propane Refrigerant Storage
Pump (074-P-1002) are filled with liquid during shut-down of make-up and their pump ventvalves on 074-EF-1711 and 074-PF-1711 are normally open for quick pump start , considering
because that pump liquid introduction would takes a longer time to prevent sudden thermal
shock. . Ifif no pump liquid filling to prevent sudden thermal shock.
7.3 Long Period Shut-down
The procedure of long period Shut-down is same as that of short period shut-down. However, the
following actions are required:
When the Refrigeration Unit 051/052 are shut-down for a maintenance, all transfer lines from/toUnits 051/052 are emptied by blowing nitrogen gas into the storage tanks bullets from temporary
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(4) If tank has been opened to the atmosphere it must be dried.
(a) Dry and inert with nitrogen from the utility station. Use the procedure from Section 4.3 2 2.(b)
and (c) as appropriate using nitrogen rather than defrost gas.
(b) When dry slowly add small quantities of liquid propane into the storage tank bullet andallowing it to boil off at ambient temperatures and pressure. Vent boil off vapors to the dry flare
by opening 074-PV-1212A/B.
(c) Repeat (b) until the percent nitrogen is less than 0.5%. TBD
(d) Introduce liquid propane per Section 4.4.1
(5) If the bullet has not been opened to the atmosphere iIntroduce liquid propane ser section 4.43.12.
8.2.4 074-US-2100 Ethane Refrigerant Storage BulletRepressurization Isolation(1) As the minimum depressurizing temperature (-97 ºC) is below the vessel’s MDMT (-45ºC) at
design pressure (29kg/cm2G), special consideration must be taken. Note that the allowable
pressure is 11 kg/cm2G at the minimum depressurizing temperature. See also allowable
operating condition based on ASME Section VIII Division 2 (Attachment 6).
(2) Allow the storage tank bullet to warm to ambient temperature atmospheric pressure.
(3) After maintenance is completed. (See Sections 10 &11)
(4) Reset the safety interlocks.
(i) Reset Total Reset 074-HS-2100B from the MCR. Note that ESD valves(074-USVE-2010/2050) can be reset after skin temperature permissive is on.
(ii) Reset solenoid valve latches for the following USVEESD valves 074-USVE-2040A/D2010
and 074-USVE-/20002020/2050.
(5) If tank has been opened to the atmosphere, it must be dried per Section 4.3 2 (2),(3),(4), and (5).
(6) Fill per Section 4.43.1. Note that the minimum operating temperature at design pressure is
-42 ºC. After any event where the vessel temperature drops below -42ºC, the vessel must be
warm up to more than -42ºC before fresh make-up is introduced into the tank.
8.3 Utility Failure
8.3.1 Electric Power Failure
During electric power failure, motor driven equipment, such as pumps, are stopped resulting in
delaying the refrigerant make-up operation.
8.3.2 Utility Water Failure
There is no user of utility water, except for hose stations in Unit 074.
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safety valves, and inspections and repairs of equipment that cannot be shutdown or removed during
Production.
11.2 Precautions prior to Maintenance
This section covers precautions prior to start maintenance work for a whole or a part of the plant.
• All work must be carried out within the requirements of company Safety & Environmental
Policies and Procedures. Prepare all known Work Permits, these must reflect safety issues.
Obtain relevant permit to work before starting work.
• Inform Operations of the work content of this preventive maintenance procedure and how it will
affect them.
• All rotating equipment is to be considered energized until proven isolated.
• All vessels must be isolated, drained and vented.
• Cordon the work area, to prevent unauthorized access.
• Prior to commencement of this work ensure that moving/rotating/power generating/energy
storing equipment has been isolated in accordance with the relevant permit to work and lock-out /
tag-out requirements.
• Physically isolate vessels. Only standard blank flanges and spades should be used. No person
should enter a vessel unless all directly connected sources of utilities fluids have been positively
isolated from the vessel. Entry means total body entry or any part of the body.
• Operations should check for oxygen, taking samples at several representative places, with a
portable analyzer to check for oxygen deficiency.
• Prior to commencement of this work it is recommended that the crew will be briefed on what isrequired and what hazards there are. The crew will be reminded of the location of safety showers,
first-aid boxes and telephones.
11.3 Preparation for Maintenance
The outline of the work sequence begins as below.
• Shutdown of the unit operation
• Installation of isolating blank flanges or spades
• Replacement with air for entry into the equipment, if required
11.3.1 Installation of blank flanges or spades
Isolating blank flanges or spades must be installed at locations as required.
11.3.2 Replacement of Nitrogen with Air
Replacement of nitrogen gas with air and safety test for equipment must be performed prior to
permitting entry.
(1) Connect temporary air hoses at the appropriate location with utility air or instrument air if
required.
(2) Open the top vent valves and drain off valves to atmosphere of the equipment.