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New nitrogen pressurization system

After two years of development by the Cargo Handling System design team, GTT can now present the new nitrogen pressurization system Evolution 3 for the NO96 membrane containment systems. Extensive work involving GTT Process & Instrumentation and Stress Piping specialists has been conducted leading to the full acceptance by Daewoo Shipbuilding and Marine Engineering shipyard. Application of the new nitrogen pressurization system on future LNG units equipped with GTT NO 96 membrane containment system such as LNG Carriers, but also FSU/FSRUs and offshore FLNGs can now go forward.

This evolution of the NO96 nitrogen pressurization system was inspired by the Mark III system, a nitrogen pressurization solution that has proved its reliability and efficiency over the years.

Development studies including functional analysis of the system, process flow and PID diagrams have demonstrated the full compliance of Evolution 3 with the IGC code. Piping optimisation has been performed to remove the requirement for cryogenic nitrogen pipes and also to save space on the vessel deck. Detailed complementary studies such as the definition of equipment list and associated specifications, and piping flexibility calculation (see Figure 1) have been conducted to fully validate this new nitrogen pressurization system.

In case of gas pollution in one insulation space, the independence offered by the system allows an easier and more efficient maintenance of the polluted insulation space while the others tank insulation spaces remain normally regulated, and remain without any risk of being contaminated by any pollution.

It should also be noted that Evolution 3 is fully compatible with all the evolutions of NO96 CCS (perlite, glass wool, L03/L03+) without any modification of the insulation.

3D model for piping flexibility calculations

These significant improvements brought by Evolution 3 offer to the NO96 containment systems additional operational flexibility and enhance the safety of its insulation spaces.

Cargo tanks equipped with NO96 containment system respond now much more to operators’ expectations for FSU/FRSU, FLNG and even LNG fuelled applications when tank segregation is required.

GTT has obtained an Approval in Principle from the Bureau Veritas, the American Bureau of Shipping and the Lloyd’s Register, for the new NO96 pressurization system Evolution 3.



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