AiPs Obtained for Liquefied CO₂ Carrier Design and Floating Liquefied Storage Facility

Knutsen NYK Carbon Carriers AS (KNCC), a subsidiary of Nippon Yusen Kabushiki Kaisha (NYK) and Knutsen Group, has obtained Approval in Principle (AiP) from ClassNK for the design of liquified CO₂ carriers (“LCO₂-EP carrier”) that use the elevated pressure (EP) method to store and transport liquefied carbon dioxide (LCO₂) at ambient temperature. ClassNK has carried out a design review of this ship in accordance with the Rules for the Survey and Construction of Steel Ships, “Part N,” and has issued an AiP after confirming that the ship meets the prescribed requirements.The LCO₂-EP carrier uses LCO₂-EP Cargo Tank technology developed by KNCC to transport LCO₂ in a stable state. Since there is no need to cool LCO₂ to cryogenic temperatures, it is easy to handle and potentially reduces energy and costs during liquefaction.

NYK, KNCC, and ENEOS Xplora Inc. have developed a Floating Liquefied Storage Unit (FLSU) that combines the LCO₂-EP Cargo Tank technology with the Isenthalpic Expansion Cooling & Liquefaction Process. This Process has been researched and developed in collaboration among the three companies. ClassNK has issued an AiP following a review based on the Rules for the Survey and Construction of Steel Ships, “Part PS,” Guidelines for the Design of Floating Liquefied Natural Gas and Liquefied Petroleum Gas Production, Storage, Offloading and Regasification Units, etc.

This FLSU is a pioneering concept that liquefies and temporarily stores CO₂ that has been collected and transported as gas in an onshore facility, making it ready for further transport by LCO₂ carrier. By utilizing the features of the EP method, which has the potential to reduce the energy required for liquefaction, and adopting the Process, which is expected to be simpler and more compact than conventional cooling methods, it has become possible to install a liquefaction plant on a floating structure.

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Carbon Capture, Utilization and Storage (CCUS) is one area that is expected to play a certain role in achieving a carbon-neutral society. However, issues need to be addressed, such as reducing overall costs and securing land for liquefaction and storage facilities. By utilizing this FLSU, the cost of CO₂ liquefaction and the land area required onshore in the CCUS value chain can be reduced, expanding the possibilities for realizing CCUS.

NYK, KNCC, ENEOS Xplora, and ClassNK will continue to contribute to realizing a carbon-neutral society by examining various technologies and assessing their economic and safety aspects towards achieving a CCUS value chain.

AiP presentation ceremony
Front row, from left: Masaki Matsunaga, Executive Vice President, ClassNK; Tetsuo Yamada, Executive Vice President, ENEOS Xplora; Synnøve Seglem, Director, KNCC; Tsutomu Yokoyama, Executive Officer, NYK
Second row, from left: Akio Usami, General Manager of Hull Department, ClassNK; Michitaka Miyama, General Manager, CCS Project Department, ENEOS Xplora; Jorunn Seglem, Deputy Director, KNCC; Anders Lepsøe, Managing Director, NYK Group Europe Norway; Oliver Hagen-Smith, CEO, KNCC; Jarle Østenstad, Director, KNCC

Comments from each company

Tetsuo Yamada, Executive Vice President, ENEOS Xplora Inc.The Floating Liquefaction Storage Unit concept was developed with the aim of assisting in resolving the challenges faced by many emitters, such as land use constraints and costs associated with liquefaction, in the realization of CCUS...

Tsutomu Yokoyama, Executive Officer, NYK LineIn August 2024, NYK, KNCC, and ENEOS Xplora succeeded in the demonstration experiment to study the CO₂ liquefaction process and have continued further discussions toward social implementation...

Oliver Hagen-Smith, CEO, Knutsen NYK Carbon Carriers ASI am delighted with this achievement and the continual collaboration with ENEOS Xplora...

Masaki Matsunaga, Executive Vice President, ClassNKWe are honored to be able to issue Approval in Principle (AiP) for the innovative initiatives of three leading companies...

About ENEOS Xplora Inc.

Head office: Tokyo, JapanRepresentative: Toshiya Nakahara, President and CEOWebsite: https://www.eneos-xplora.com/english/

About Nippon Yusen Kabushiki Kaisha (NYK)

Head office: Tokyo, JapanRepresentative: Takaya Soga, PresidentWebsite: https://www.nyk.com/english/

About Knutsen NYK Carbon Carriers AS

Head Office: Haugesund, NorwayRepresentative: Oliver Hagen-Smith, CEOWebsite: https://www.kn-cc.com

About ClassNK

Head Office: Tokyo, JapanRepresentative: Hayato Suga, President & CEOWebsite: https://www.classnk.com/hp/en/index.html

• Approval in Principle (AiP) indicates that the basic design has been reviewed by a certification body and approved as meeting technical requirements and safety standards.** LCO₂-EP Cargo Tank has been developed by KNCC to transport LCO₂ at ambient temperatures and elevated pressures (0 to 10 degC / 34 to 45 barG).*** The isenthalpic expansion cooling & liquefaction method adopted in this Process takes advantage of the temperature drop caused by depressurizing the captured CO₂ to form a liquefied CO₂ suitable for marine transport.**** CCUS (Carbon Dioxide Capture, Utilization and Storage) includes a process in which the CO₂ emitted from power plants and factories are collected and either used in the production process of crops, chemicals, construction materials, etc. or stored in stable underground geological formations.