Floating production, storage and offloading vessels, FPSOs, have been around for decades allowing operators to produce oil from an offshore field and transfer the cargo to a ship. There’s even one such vessel that produces and offloads liquefied petroleum gas offshore Angola and the world’s first LNG FPSO (FLNG) is well on its way to be commissioned in 2015. With the continual push for more environmentally friendly sources of energy, hydrogen – the cleanest burning source of energy, is gaining strong attention.
During the process of producing hydrocarbons from an oil well, hydrogen gas and carbon dioxide are also produced in significant quantities as a byproduct. Japanese firms Chiyoda and Mitsubishi Heavy Industries, with support from ClassNK’s Joint R&D for Industry Program, have come up with a new vessel concept that utilizes steam reforming and shift conversion to extract these gases and store them until they can either be transported off the vessel or re-injected back into the reservoir to help maximize the production of the field.
The H2/CO2 FPSO uses a new organic chemical hydride method to convert hydrogen into highly stable methylcyclohexane (MCH), which can be stored in liquid form at an ambient temperature and pressure. As MCH can be transported in standard chemical tankers, converting hydrogen into MCH not only reduces the risks and challenges related to hydrogen storage, but also optimizes it for transport using existing transportation networks. MCH produced by the H2/CO2 FPSO could then be transported by chemical tankers to hydrogen demand sites and converted back to hydrogen using a dehydrogenation reactor developed by Chiyoda.
The new design is understood to be world’s first H2/CO2 FPSO design, as well as the first such facility to receive Approval in Principle (AIP).
ClassNK notes AIP is an essential step in the process of developing conceptual designs for practical application in the maritime and offshore industries. As part of the process, the Japanese class society conducted an extensive review of the concept design, including both risk assessment and a thorough review of structural and topside plans for the H2/CO2-FPSO to ensure the design complies with both ClassNK’s independently developed rules and relevant international regulations and standards.