Next Generation of LNG Regasification Terminal through TG`s

NEXT GENERATION OF LNG REGASIFICATION TERMINAL THROUGH
TG’S PROFOUND KNOWLEDGE
– TOKYO GAS HITACHI LNG TERMINAL –
Tsutomu Endo
Tokyo Gas Corporation, Japan
www.tokyo-gas.co.jp
KEYWORDS：knowledge, shortened construction period, limited land area, energy saving
ABSTRACT
Tokyo Gas Co., Ltd., the world's 4th-largest LNG importer, imports 17MTPA of LNG with our own shipping fleet
at 3 regasification terminals along Tokyo Bay. It has been steadily supplying city gas, as the Japan's largest
gas supplier, which has over 10 million city gas customers and many industrial customers including power
stations. The demand for natural gas has been increasing since the magnitude-9 Great East Japan
Earthquake, which struck on March 11, 2011. This is giving Tokyo Gas an even greater role to play as an
energy supplier in the aspect of providing for energy resources and assuring energy security. Under these
circumstances, Tokyo Gas, creating robust supplying chain, decided to construct a fourth LNG regasification
terminal in the vicinity of Hitachi, about 130 kilometers northeast of Tokyo. One of the features of the Hitachi
LNG Terminal is the ability to deal with LNG of various calorific types, from the conventional rich types to the
super-lean types such as coal bed methane (CBM) and shale gas, with new-type LNG jet mixing system
against LNG stratification in a tank. Furthermore the terminal will be equipped with an aboveground LNG tank
with a capacity of 230,000 cubic meters, the world's largest. It will be constructed in a challengingly short
period of time which is less than 3 years with the technology for shortening construction periods. TG's profound
knowledge acquired over the last 40 years of experience in engineering, operation and maintenance will
enable us to build a terminal of the very latest kind of technology such as accommodating with LNG calorific
diversification and the largest LNG tank. This paper presents an overview of the Hitachi LNG terminal facilities,
which incorporate the most advanced technology.
1 INTRODUCTION
Since Tokyo Gas first introduced to LNG in Japan in 1969, it has built and operated 3 LNG terminals over the
past 40 plus years. Japan’s first LNG plant, the Negishi LNG terminal, was built to supply city gas for the
western part of the Tokyo metropolitan area, and imported LNG from Alaska for the first time in 1969. The
Negishi terminal was the first in the world to implement a system to utilize the cold energy of LNG for
maximizing the cost effectiveness of LNG fuel. Subsequently, for the full scale implementation of LNG supply
infrastructure, Tokyo Gas built pipeline in the periphery of the Tokyo metropolitan area, and constructed the
Sodegaura Terminal in 1973, one of the largest LNG terminals in the world. Following necessary expansions to
the Negishi and Sodegaura Terminals, the third LNG terminal, the Ohgishima Terminal, was built in 1998 to
meet the increasing demand for gas. Various state-of-the-art technologies were implemented in the process of
constructing the Ohgishima Terminal, including that of fully buried (underground) tanks, an energy-saving BOG
processing system, and other features which made it one of the most advanced terminals in the world.
In predicting a further increase in the demand for gas, Tokyo Gas will construct its fourth LNG terminal, the
Hitachi LNG Terminal, for the first time in around 20 years after the construction of Ohgisima Terminal.. In
planning this new terminal, Tokyo Gas intends to capitalize on the knowledge it has accumulated over the past
40 plus years for the terminal’s design, construction, and operation in order to achieve lower both CAPEX and
OPEX and to maintain the established levels of high safety and gas supply stability of other terminals, while
managing the existing issues of limited land area and a shortened construction period.
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This paper is discribed the overview of Hitachi LNG Terminal together with the associated issues to be
addressed in its construction.
2 OVERVIEW OF THE HITACHI LNG TERMINAL
2.1 Site Location
As shown in Figure 1, the Hitachi LNG Terminal will be constructed in the north east part of Tokyo. The
planned site location is outlined in Figure 2, and Figure 3 presents a bird’s eye view of the terminal.

Hitachi LNG
Terminal
Ohgishima LNG
Terminal

Location: Ibaraki Port, Hitachi district of Hitachi City,
Ibaraki Prefecture
Area: approx. 104,000 m2 (about 1/3 the size of the
Ohgishima Terminal)
Hitachi port
area
Sodegaura LNG
Terminal
Hitachi LNG
Terminal
Negishi LNG
Terminal
Pier of 4
TG’s Pipe line
Pier of 5
Other company’s Pipe line
TG’s supply area
Kuji gawa
river
TG’s group supply area
Other company’s supply area
Figure 2. Planned Site Location of the Hitachi LNG
Figure 1. Location of Hitachi LNG
Figure 3. Bird’s Eye View of the Hitachi LNG Terminal (Phase I)
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2.2 Master Schedule
Table 1 shows the master schedule for the construction of the Hitachi LNG Terminal. Construction of the
terminal has been planned in two phases, Phase I and Phase II, with Phase I scheduled to start operation in
FY2015. While the most critical part of this schedule is the construction of the above ground storage tank,
various ideas will be used to reduce the construction period from an estimated 48 months to 35 months,
requiring a mere three and a half years from preparation to finish.
Table 1. Master Schedule
FY2012
Milestone
FY2013
FY2014
FY2015
▼Land acquisition and commencement of construction
▼Commence operations
Site preparation
Preparatory work
Offshore work
Land work
Commissioning
2.3 Terminal Capacity
Table 2 shows capacity and other data for the terminal for Phases I and II. The Hitachi LNG terminal will be
designed to allow further increases in plant capacity through the addition of supplementary systems to cope
with possible increases in demand in the future.
Table 2. LNG Handling/Send-out Capacity
Item
Gas
transmission
Capacity
Phase I
Phase II
1 million tons /year
2.2 million tons /year
(1320 million m3 /year)
(2900 million m3 /year)
Liquid
0.6 million tons /year
1 million ton /year
delivery
(760 million m3 /year)
(1270 million m3 /year)
Total
Maximum gas delivery
Gas calories
Maximum ship capacity
1.6 million tons /year
3.2 million tons /year
(2080 million m3 /year)
(4160 million m3 /year)
200 t/h
500 t/h
(264,000 Nm3 /hour
(659,000 Nm3 /hour)
45 MJ/Nm3
45 MJ/Nm3
LNG: 177,000 kl
LPG: 80,000 kl
2.4 Equipment Specifications
Figure 3 below shows the process flow for the Hitachi LNG Terminal while Table 3 outlines the terminal’s
equipment specifications. As the terminal has been designed for the shipping of LNG in addition to supplying
city gas via pipelines, those for shipping LNG by coastal tankers and lorry trucks for domestic users are to be
constructed. For LNG boil-off gas (BOG) processing, a medium pressure compressor offering lower running
costs will be used for reliquefaction, and will be combined with a high pressure compressor for directly sending
to pipeline in order to provide less restriction on the terminal’s minimum send out requirements. For LPG BOG
processing, an LPG BOG suppression system will also be employed to help with lower running costs.
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LNGBOG
recondenser
LPG receiving
facility
Flare stack
High pressure
LNGBOG comp
Middle pressure
LNGBOG comp
M
LNG receiving
facility
LPGBOG
suppression system
Vent stack
M
LNG shipping
by domestic ships
BOG calorie control
system
LNG RGB
LPG RGB
LNG HP
LNG tank lorry
shipment
LPG HP
ORV
Supply gas
TP1 LPG tank
TL1 LNG tank
LPG Line
LNG Line
Gas Line
Figure 3. Process Flow of Hitachi LNG
Table 3. Equipment Specifications
Facility
Facility Specifications
Jetty for import LNG/LPG
16B arm for LNG x3, 16B for LNG RG x 1
LNG/LPG receiving facility
12B arm for LPG x3, 12B for LPG RG x 1
LNG RGB 27,000 m3N/h x 1
LPG RGB 2,000 m3N/h x 1
Sampling facility 1
LNG shipping by domestic ships
Jetty for shipping LNG for domestic users
8B arm for LNG x1, 8B for RG x 1
LNG storage tank
PC above ground storage tank, 230,000 kl x 1
LNG vaporizer
ORV100t/h x 3
LP: 130 t/h x 6
LNG pump
HP: 105 t/h x 4
LP for shipping LNG: 350 t/h x 2
BOG compressor (medium pressure): 11,500m3N/h x 1
LNG BOG processing facility
LNG shipping facilities (lorry
trucks)
LNG storage tank
LPG pump
LPG BOG processing facility
BOG compressor (high pressure): 15,100m3N/h x 2
BOG reliquefaction equipment: 11,500m3N/h x 1
40 t/h x 6 lanes
PC above ground storage tank, 50,000 kl x 1
LP: 46 t/h x 6
HP: 28 t/h x 4
BOG suppression system: 2,200 m3N/h x 2
4
Pipe Line
3 CHALLENGES FOR THE HITACHI LNG TERMINAL
3.1 Construction of the world's largest capacity LNG tank
For the Hitachi LNG Terminal, Tokyo Gas is planning to construct the company's first, and world's largest
capacity, above-ground LNG storage tank using pre-stressed concrete (hereafter referred to as an "above
ground PC tank"). Figure 4 illustrates the major structural elements of this above ground PC tank. The tank is
composed of an inner tank made of 9% Ni steel to store LNG, a PC liquid protective barrier to prevent any
leakage to the outside in the unlikely event of a leak in the inner tank, support piles to support the structure,
and other structural components.
Inner Tank
In conventional design, the maximum possible
capacity of an above ground PC tank was
considered to be 180,000 kiloliters. However,
according to March 2008 amendments to the
Insulation
Japanese Gas Business Act, the structural
design is now allowed to use a safety coefficient
of 3.5 (according to JIS B 8267) for the
allowable stress of structural members of the
Outer Tank
inner tank in addition to the conventional
selection of 4.0 as a safety coefficient.
PC Liquid Protective Barrier
Figure 4. Schematic Diagram of Above Ground PC
A safety coefficient of 3.5 for allowable stress has made it possible to construct an unprecedented 230,000
kiloliter above ground PC tank. As increased tank capacity allows for a reduced number of necessary tanks,
the required area for the site can be reduced.
3.2 Reduced construction period for the terminal
The construction period for the LNG tank is the most critical in the construction of the entire terminal. In order
to realize the terminal’s planned FY2015 start, conventional construction methods commonly used in Japan
were deemed to be insufficient for meeting this three and a half year schedule. Through the implementation of
new procedures, it is now estimated that the construction period for the LNG tank of the Hitachi Terminal will be
reduced from its original estimate of 48 months to 35 months. Table 4 shows a comparison of the conventional
schedule and the current schedule. The main factors contributing to this reduction in the construction period
are described below.
< The implementation of new procedures >
(1) Construction of the inner tank first
(2) Modular construction of reinforced steel frames
(3) Pre-fabrication and marine transport of structural components
(4) Detailed and organized work management to enable parallel work
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Table 4. (A) Conventional Construction Methods: Building the Outer Tank First (48 Months)
(5)
2nd year
1st year
Civil engineering
work
Outer tank construction
(incl. liquid protective barrier)
Foundation
work
Mechanical work
Roofing work
3rd year
Air raising (A/R)
4th year
Insulator work
Completion
Test
Inner tank
Insulator work
Table 4. (B) Construction Method Adopted: Building the Inner Tank First (35 Months)
1st year
Civil engineering
work
Foundation
work
2nd year
Outer tank construction
(incl. liquid protective barrier)
Roofing work
4th year
Insulator work Completion
A/R
Test
13 months reduction
Inner tank
Mechanical work
Modular construction of
reinforced steel frames, etc.
3rd year
Pre-fabrication and marine
transport of structural components
Insulator work
Detailed and organized work management
to enable parallel work
<Factors in shortening the construction period >
(1) Construction of the inner tank first (Air raising of the inner tank)
Figure 5 shows an outline of the two different construction methods, i.e., (a) building the outer tank first
and (b) building the inner tank first. Here, the A/R (air raising) method uses air pressure to lift the roof
assembled on the tank floor for mounting on top of the tank. With the differential pressure of 2 to 3kPa
(referenced to atmospheric pressure), a lifting rate of 250 to 300 mm/min is achieved, and thus the lifting
work can be completed in a few hours, while the tilt of the roof is monitored and properly controlled. In the
case of a well-practiced outer tank air raising method, air raising is conducted after the liquid protective
barrier has been completed and the side plates for the inner tank have been constructed. However, as the
inner tank air raising method allows for the simultaneous construction of side plates for the inner tank and
the liquid protective barrier, it can significantly reduce the construction period.
By reducing the construction period for the LNG tank, the construction period for the entire terminal can
also be reduced.
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Completion of the outer tank and the
Construction of the liquid protective roofs of the inner and outer tanks
barrier and outer tank begins after
基礎版製作後、防
construction of the base structure is
液堤および外槽の
completed
作成
Outer tank
外槽
Liquid protective barrier
防液堤
Inner tank
内
A/R of the roofs
of内槽・外槽屋根
the inner and
outer を
tanks
槽Inner tank
Anchor strap
アンカー
ストラップ
Figure 5(a) Construction method to build the outer tank first
The liquid protective
and the outer
Parallel construction of the barrier 防液堤・外槽も
inner tank and the
roofs of tank are constructed at
内槽および内槽・外
the same 同時施工
time
the inner and outer
tanks
槽屋根を施工
Air raising is performed following completion of
the liquid
protective barrier, side plates of the
防液堤・内槽側板・
inner外槽製作後
tank, andA/R
theを行
outer tank
なう
A/R of the roofs
of内槽・外槽屋根
the inner and
outer tanks
をA/R
Figure 5(b) Construction method to build the inner tank first
3.3 Energy saving measures
In the construction of the Hitachi LNG Terminal, a variety of approaches are being taken in order to save
energy and reduce running costs. From among these approaches, the LNG BOG recondenser system and the
LPG BOG suppression system, which both offer substantial energy savings, are introduced below.
(1) The LNG BOG recondenser system
In an LNG BOG recondenser system, the cold energy of LNG is used to liquefy boil-off gas (BOG) under
medium pressure. The liquefied gas is then pumped for gasification by ORV, a method that has been used in
the Ohgishima LNG Terminal. Compared with the direct heat exchange method, an estimated about 30%
reduction in the LNG BOG condensing rate can be expected. Figure 6 illustrates the process flow of the LNG
BOG recondenser system.
The boil-off gas generated in the LNG tank is pressurized by the LNG BOG compressor and sent to
recondenser for liquefaction. The pressurized BOG is first sent to precooler and then introduced to the
recondenser. The pre-cooled BOG is liquefied in the LNG BOG condenser through the heat exchange process
to use LNG, and the resulting re-liquefied LNG is stored in the LNG condensate drum. The liquefied LNG is
then pressurized to the send out pressure with the LNG condensate pump, which pressurizes the liquefied
LNG to the send-out pressure (i.e., for gasification), and sent to ORV for regasification..
<Features of the recondenser system>
① As the pipeline network of Tokyo Gas does not have the underground storage systems typically found
in the USA and Europe, it is necessary to absorb seasonal and hourly fluctuation on the LNG terminal
side. As such, in order to mitigate possible restrictions due to the minimum send-outflow rate , the LNG
BOG condensing rate should be kept as low as possible.
② As the process to pre-cool BOG can keep the LNG BOG condensing rate at a low level, the limitation
due to the minimum send out requirement can be mitigated.
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LNG BOG Cooler
LNG Condenser
LNG BOG Compressor
BOG
LNG Condensate Drum
LNG Pressurization
Pump
LNG Tank
LNG Condensate Pump
Vaporizer
LNG Line
Figure 6. Process Flow of LNG BOG Recondenser System
(2) The LPG BOG suppression system
LPG is stored under atmospheric pressure. Heat leakage into the tanks, therefore, must be transferred out of
them as boil-off gas. Conventionally, LPG BOG is pressurized via a compressor and re-liquefied by cooling
water. Since large-scale motor-driven compressors have been used in this recovery system, the comsumpiton
of electricity is considerable.
In order to cut the cost of recovery of BOG and reduce energy consumption, the suppression system
developed by Tokyo Gas has been developed utilizing the cryogenic energy of LNG and introduced to
Ohgisima LNG terminal. LPG BOG is forced to condensate in a tank by the super-cooled LPG that is cooled by
LNG. This system needs no high-pressure compressors, so that the total cost is much lower than with
conventional system. In this system, LPG pumped up from the tank is fed into a heat exchanger and is
supercooled with LNG. Then, the supercooled LPG is re-introduced into the gas layer of the tank through a
spray device and supercooled LPG cools and condenses the BOG. Figure 7 illustrates the process flow of the
LPG BOG suppression system.
LPG Cooler
Tank Spray
LNG Line
LNG
Pressurization
Pump
LPG Tank
Vaporizer
LPG BOG Line
Figure 7. Process Flow of the LPG BOG Suppression System
3.4 Facilities for LNG shipment
As the Hitachi LNG Terminal is designed with the aim to large scale LNG shipments to the Northern Kanto,
Tohoku, Hokkaido areas and so on, LNG shipment facilities by both coastal tankers and LNG lorry trucks for
domestic customers are to be installed. The features of these facilities are described below:
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(1) LNG shipment by coastal tankers
The LNG shipment facility is designed for use by large ships of a 10,000 ton class, in addition to servicing
conventional 1,000 ton class domestic vessels. To cut down on cost, the LNG receiving facilities are also used
for LNG shipments by 10,000 ton class vessels. Specifically, the LNG receiving line is reversely used to send
LNG to the domestic ship and the return gas line is used to carry the return gas from the ship.
(2) LNG shipment facility by lorry trucks
With its limited area and layout restrictions, the LNG shipment facility for lorry trucks at the Hitachi LNG
Terminal are efficiently designed to maximize shipping capacity. As a high filling rate of 40 t/h has been verified
in a verification test conducted at the Sodegaura LNG terminal, the maximum filling rate of 40 t/h is assumed
for initial operation. As future increases in the filling rate can be expected through modifications to the tank lorry
receiving line facilities, the system is designed to operate at a maximum filling rate of 60 t/h.
3.5 Acceptance of lean LNG
Due to the diversification in the types of liquids received in recent years, it is expected that the ratio of lean
LNG will increase in the future. Accordingly, the Hitachi LNG Terminal will be designed to accept
unconventional LNG (e.g., CBM) in addition to conventional LNG. In order to avoid density stratification, which
may result when different types of LNG are stored in the same tank, appropriate operations are required to
monitor the LNG density distribution in the tank. In addition, in the event that layering does occur, remote
controlled jet mixing will be performed to prevent rollover.
3.6 New approach for the process control system
Various approaches are being studied to improve reliability and operational efficiency of the process control
system (DCS) of the Hitachi LNG Terminal utilizing over 40 years’ experience of operation. Some examples of
these approaches are discussed below:
(1) Cyber security measures
In recent years, there has been an increase in cyber attacks targeting various control systems, and a variety of
attack methods have been used. In order to respond to the continually evolving cyber security threats,
penetration tests based the assumption of cyber attack will be conducted upon introduction of the system.
Following the system’s introduction, security diagnosis activities will take place regularly, and will include
system vulnerability checks and as well as any necessary actions.
(2) Introduction of operator assistance tools
① Adaptation of alarm management methods
In order to avoid any mistakes in recognizing indications of significant trouble due to the temporary
generation of a large amount of alarms, the most important alarms are to be placed at the top of an
alarm list in order of priority. In addition, in order to prevent any oversight due to frequent or large
amounts of alarms generated, past alarm histories will be reviewed and analyzed to reduce any
unnecessary alarms in the future.
② Effective use of the operator training system
In order to help accelerate the training of operators and to maintain their level of skill, an advanced
operator training system employing a plant mode, DCS system simulator will be introduced in this
terminal. Furthermore, DCS system will be designed with the aid of process simulation by DCS
system simulator, which trial will be for the first time in Japan. The training system will be developed
and implemented at an early stage (i.e., before the actual implementation of the control system).
The model will be used to represent the design of the control system in order to train operators prior
to the start of the LNG terminal operation. In addition, a method that will systematically analyze the
actions of individual operators and present objective evaluation results to indicate their rated level of
mastery will be introduced.
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③ Introduction of trend-based operation
The introduction of "trend-based operation" is also planned for the first time in the world. With this
system, through the overlay of current operational data on a template that shows trend plots to
represent normal operations, possible equipment failure can be easily detected and the differences
clearly and promptly indicated to the operator.
3.7 Cost reduction efforts
In past LNG terminal construction cases, equipment suppliers were selected based on an evaluation of the
initial costs of installation. In the case of the Hitachi LNG Terminal, the vendor selection policy has been
changed to incorporate consideration for total life cycle cost (LCC), which includes an evaluation of the initial
costs and the running cost after operations have begun, e.g., cost of electric power, maintenance costs, etc.
This policy enables the low cost and competitive operation of the LNG terminal.
4 CONCLUSION
While the construction of the Hitachi LNG Terminal involves some challenging issues such as land limitations
and a shortened construction period, in an effort to resolve issues and realize a competitive LNG terminal,
Tokyo Gas aims to maximize the user engineering technologies and knowledge that they have accumulated
over their 40 plus years of experience in the design, construction, and operation of their LNG terminals to date.
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