Hydrocarbon Processing - June 2022 - GP-25

LNG
Simplified simulation model
for an LNG terminal
J. W. CHANG and D. KOLTE, CTCI Corp., Taipei, Taiwan
The natural gas liquids/liquefied natural
gas (NGL/LNG) value chain encompasses
the production, processing and
liquefaction of natural gas (NG) to LNG,
its long-distance transportation, and its
regasification as it travels from the wellhead
to end users. An LNG terminal is an
important part of the NGL/LNG value
chain and is used at the final stage to unload
LNG and distribute NG to users.
Considering that approximately half of
the total cost of an LNG terminal project
comes from equipment and critical lines,
the finalization of the facility's capacity
and equipment size verification are critical
during the bidding stage. In general,
30-40 operating cases exist in an LNG
terminal, so reviewing and checking all
operating cases are time-consuming tasks.
Ship and BOG return section
BOG_ARM-SHIP
V1
RG_COND
BOG_SHIP
TK_HL+PL
BOG_TK_PL
SUM_BOG_SHIP
PSEUDO
BOG_SHIP
SHIP
IN_SHIP
TK_INT
TANK
QF-1
SHIP_HIN2
SHIP_RICH
SHIP_LEAN
US1
SHIP CARGO_PUMP
LNG unloading
section
PS2
HOLD_CL
1
FEED_LEAK
S6
CN2
PI3
S12
SP_LP_PUMP
IN_TK
FIG. 1. A typical simplified LNG terminal simulation model.
Gas Processing & LNG | MAY/JUNE 2022 25
TK_LIQ
BOG_PL
S11
6
PI1
TANK_D
S10
TK_SUMP
12
PI2_1
11
LP_SF
INTANK_PUMP
In tank pump section
HP pipe keep cool section
LPC
US4
HP_PUMP
S7
LP_CLG
DISP
SP_TO_RC
13
S3
HP_S
HP_CLG
HP_VAP
HP_CLR
LP_HP_LINES
LP_CLR
TK_IN
S2
RC
21
TK_BOG-0.05
TO_CMP_BOG
BOG_FHL
64
REC.
RC_BTM
HP pump and
condenser
section
22
ORV
TO_IFV
TO_ORV
23
S1
PI2
HPC
BOG_H_LC
SP1
TANK_BOG
CL_R
BOG_DISP
TO_SHIP-_PP ARM_SHIP
60
LNG tank section
S4
SP2
BOG_HDR
BOG_HDD
53A
S9
This article will focus on the applicafor
front-end engineering design
tion of a shortcut rigorous simulation
model1
(FEED) to ensure the optimum design for
cost estimation during the bidding stage
to secure competitive advantage.
Operating cases in an LNG terminal.
Operating cases in LNG terminals are
based on various factors, such as LNG
composition [lean/rich/high nitrogen
(N2
)], ship unloading status (unloading/
holding-no unloading), NG send-out
flowrate from the terminal (maximum/
minimum/zero), send-out condition
(high-pressure, low-pressure), ship loading
rate from the LNG terminal (if the
ship loading provision is considered), etc.
With the above prescribed conditions,
RGP
59
RG
RGB
various required operating cases are summarized
here:
1. Ship unloading minimum and zero
send-out case (lean/rich/high N2
2. Ship unloading maximum
send-out case (lean/rich/high N2
3. Ship unloading normal send-out
case (lean/rich/high N2
)
4. No ship unloading (holding)
minimum and zero send-out
case (lean/rich/high N2
)
5. No ship unloading (holding)
maximum send-out case
(lean/rich/high N2
(lean/rich/high N2
)
6. No ship unloading (holding)
normal send-out case
)
7. NG battery limit send-out
pressure (high/low).
BOG compressor section
ZERO_COMP
55
US3
53
V-1
S8
S5
IFV
MSO_ZSO
MAXSO_ZSO
MINSO
COMP.
M1
NG sendout section
25
)
)
Hydrocarbon Processing - June 2022

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