Floating LNG
Plant Technology

Jangkrik Gas FPU
Source : http://skkmigas.go.id/

A floating LNG (FLNG) is an LNG plant constructed on a ship or a barge which has LNG storage and offloading facilities. The FLNG accomplishes the gas treatment and liquefaction (production of LNG) from the natural gases produced in offshore gas fields, and the storage/offloading of product LNG to LNG carriers for ocean transportation.

The advantages of FLNG compared with onshore LNG plant are (a) to reduce the length of long subsea pipelines that need to be built from the offshore gas fields, (b) to reduce the infrastructure and environmental impact on onshore since FLNG does not require the coastal development, and (c) to be built in fabrication yards where facilities and practices are well-established for construction of the topsides modules and hull without constraints of the countries or regions of the gas field or onshore LNG plant, which secures the efficiency and the safety of construction.

As the market seeks lower-priced LNG plants with shorter delivery in response to low LNG prices, Chiyoda is focusing on new approaches and innovative ideas for FLNG. The key point for FLNG planning is to optimize the facility arrangement and specifications, considering the specific feed gas composition, LNG production rate target, metocean conditions, at shore / near shore / open sea arrangement, in order to improve the project economics. The optimization work needs full of expertise for FLNG. Chiyoda is one of the limited number of PreFEED/FEED/EPC Contractors who can provide the full line-up solutions for FLNG. That is why Chiyoda can provide the best FLNG solution to any customer. Chiyoda is also flexible for the contract scheme including a lease contract for FLNG. The solution may include the idea of GBS and Platform Jacket instead of FLNG, when those have better economics.

In addition, to ensure the safety of operators in the limited space on a ship, Chiyoda applies FLNG safety design and analysis methods for accidents inside a plant, such as explosions, fires or leakages.
Chiyoda has experiences not only in engineering and constructing a number of onshore LNG plants, but also in engineering FLNGs and in constructing offshore plants. Chiyoda quickly responds to changing demands by taking advantage of these expertise and continuing to develop and introduce new technologies.

Key business and technology

Chiyoda is proposing the realization of safer FLNG with lower cost and shorter delivery by combining the following key advantages for Chiyoda FLNG.

1. Selection of a liquefaction process appropriate for the feed gas composition and the scale of FLNG

Chiyoda has many options for the liquefaction technologies as No.1 LNG contractor in the world, and selects the optimum technology for each FLNG project. For example, Chiyoda can adopt a liquefaction process that does not use liquid refrigerants for a 0.5 - 2 million ton-class FLNG in annual production with lean feed gas.


  • A storage system of liquid refrigerants is unnecessary.
  • A production facility or an import facility for liquid refrigerants in a floating plant is unnecessary.
  • The total volume of flammable substances can be significantly reduced since the quantity of liquid refrigerants possessed in a floating plant is limited.
  • The risk of cryogenic refrigerants leakage is limited.
  • The size is more compact and the weight is lighter than FLNG that uses liquid refrigerants.

This is one example. An advantage of Chiyoda is that the selection of the optimum liquefaction technology among many options contributes to the significant improvement of the project economics.

2. Selection of appropriate construction method for FLNG

Generally speaking, it takes time to construct the hull and LNG storage systems for FLNG newly built. Therefore the topsides plant is divided into several modules and fabricated in land in parallel with the hull fabrication and integrated on the hull deck.
The method can minimize the works at the integration, achieve the low cost and shorten duration of the construction by such Modular Method. For the newly built FLNG, Chiyoda has an attractive option to have a cylindrical shape hull to improve the economics by eliminating a turret and achieving the stable operation under the harsh metocean conditions. The newly built hull is often adopted to the medium to large size FLNG at harsh open sea.

The conversion of the used ship does not require a new construction of hull and LNG storage systems by converting a used LNG carrier as well as adding an LNG plant on this converted LNG carrier, which enables to minimize the construction of hull and LNG storage systems and realize shorter delivery and lower cost than a new FLNG construction. Since it takes shorter duration for the conversion of the hull and LNG storage systems, the smaller modules and or pieces of equipment may be installed directly on the deck. The duration of the construction can be squeezed efficiently by such Hybrid Method. The conversion of the used ship can be adopted to small and medium size FLNG at shore, near shore and benign open sea, and significantly improve the project economics.

The other method experienced in the construction of a floating gas processing plant is Skidding Method, which may be applied when large construction space is available. The plant is constructed on the large skid and shifted to the hull coming alongside the quay.

The optimum method aforementioned for FLNG construction will be recommended to improve the project economics as per the circumstances of the project. As a matter of course, further efforts for the design and or execution will be developed by Chiyoda for the recommended construction strategy. It is also the strong advantage of Chiyoda that a competitive fabrication yard will be selected for the recommended construction method. The “hands-on” management of the fabrication yard is Chiyoda’s extensive expertise proven for the past large module fabrication projects. Chiyoda will be committed to conduct the reliable project execution to successfully complete the project on time.

3. Design optimization for FLNG

Although major contributors for the economics improvement are the above item 1 and 2, it is also quite important for successful execution of the FLNG project to solve the FLNG specific design issue timely and effectively. Chiyoda will establish the effective design solutions based on the experience of the completion of the FLNG detail design. The world first class engineering capability of Chiyoda will be fully integrated into the FLNG design.

Followings are the major design issue for FLNG ;

  • System design, equipment design and structural design for the ship motions
  • Equipment and structural design incorporating the results of explosion analysis
  • The protection for the cryogenic spill, such as LNG and refrigerants
  • Design development fully considering the detail operability and maintainability
  • Effective integration of the hull facilities and plant facilities
  • Large flare system design
  • Plant design incorporating the constructability practices of the fabrication yards

The above items include the advanced analysis, which will be conducted by the specialist consultants. However rather than concentrate on the each design issue, which sometimes result in the too conservative design, it is quite important that the overall design is managed to develop the optimum facility design, which satisfies the above design issue effectively and realizes the competitive and compact plant. This effort is the important contributor for the economics improvement and the reliable project execution keeping the short delivery schedule. Chiyoda has experience to have achieved around 20% plant weight reduction during FEED level stage by proposing creative design optimization idea, satisfying the above design issue.

4. Collaboration with Marine Contractor

Chiyoda ensures the hull and marine design and offshore project execution by the partnership with the capable marine contractor. Chiyoda with the partner will provide the most attractive and competitive FLNG design and reliable execution plan, utilizing the both companies’ strengths effectively. Since the partner has extensive experiences for the lease contracts for FPSO’s, Chiyoda with the partner will develop the lease contract scheme for FLNG, if it is desired by the client.

Key projects

1. Chiyoda’s recent experiences of FLNG

You can scroll horizontally to see it.

(Confidential) (Confidential) (Confidential) Concept 2017
(Confidential) (Confidential) (Confidential) Concept 2016
(Confidential) (Confidential) (Confidential) Pre-FEED 2016,17
(Confidential) (Confidential) Australia Pre-FEED 2015,16
Coral FLNG Eni East Africa S.p.A Mozambique FEED 2014
Jangkrik FPU Eni Muara Bakau B.V. Indonesia FEED
Scarborough FLNG Esso Australia Resources Pty.Ltd. Australia Pre-FEED
Optimization Study
Abadi FLNG INPEX MAsela,Ltd. Indonesia FEED 2013
Petrobras FLNG Petrobras Netherlands B.V. Brazil FEED

2. Jangkrik Floating Production Unit Project for Eni Muara Bkau B.V.

The following photo is not an FLNG, but shows a floating gas processing plant at the time of sail away at PT Saipem Indonesia Karimun Branch (SKY: Saipem Karimun Yard). The plant was completed and the operation has started in 2017 by a joint venture company named STC JO (Saipem, Tripatra, Chiyoda Joint Operation) which Chiyoda jointly set up with PT. Saipem and Tripatra. Chiyoda is also promoting the engineering, procurement, and construction of floating gas processing plants in addition to FLNG.

Outline :

Floating gas processing plant (separation and production of gases and condensate)

Location :

Jangkrik and Jangkrik North (70km offshore East Kalimantan, Water Depth 450m), Indonesia

Source: http://skkmigas.go.id/