15 LMM V I S I O N ISSUE 23 | Q4 2025 ARTICLE As the world walks to the net zero era, which is targeting the 2050 but might slightly be move to early 2060s, it is now firm that LNG will be the transition fuel accompanied by the rest of the newly developed green fuels as hydrogen, ammonia or methanol. Accompanied with the renewable sources of energy, complete a puzzle of the energy sources with the minimum environmental effect. However, the invasion of Russia to Ukraine and the suctions followed to Russian federation, remove from the market a huge LNG supplier. Especially from Europe as an immediate buyer. Further to the agreement between USA - Europe, part of these quantities would be replaced by US Exporters. In order to serve such demand from the above agreement but also to fulfill the already existing contracts with Asia – Far East Markets, the quality of LNG start reducing to less pure methane (CH4) composition enhanced also with Nitrogen(N2). When a so-called rich LNG cargo on Early’s 2020 had Methane purity more than 97%, where among others, nitrogen included was no more than 0,2%mol, the extreme demands transformed the LNG quality composition to 90,5% methane purity and Nitrogen content more than 4 times higher to 0,9%mol. As the nitrogen is inert gas, on high content reduces the heating value of LNG, as a result the dual fuel vessel’s machinery systems, as Main Engines and Power Generators, to suffer from overconsumption of LNG or even stoppages on their attempt to meet their performance standards. However, such cargoes sold with low prices to buyers with access to grid with flexible specifications or in companies with gas blending infrastructure enable them to segregate it and advantage from it since Nitrogen can be deducted from the CO2 emission and reduce the relevant penalties. Another issue which made these cargoes very challenging is the N2 content effect to the cargo temperature. Such cargoes when loaded, might have liquid temperatures of -161,5 to -162 or even higher when classification society declared and approved the cargo tanks with design temperature of -163C. In some cases, the classification societies forced/urge by the Suppliers and cargo tanks makers, to change the vessel’s fitness certificates and declare as new design temperature of cargo tanks the -165C in order to accommodate market requests for increased volumes. Even the main engines and generators reduced performance is one part of the problem, another one is how vessel’s machinery equipment such are the Boil Off Gas (BOG) compressors which used to send the LNG vapour to Main Engines/Generators, the Reliquefaction plant and most important the relevant cargo piping affect by such low LNG temperatures. So, it was imperative that the makers of all the above equipment to provide guidance on the handling of such cargoes. Concluding, after gathering and reviewing all the limitations of makers for the case when such cargoes loaded in company’s vessels, we were able to determine with charterers specific control measures and mitigations steps, in commercial, operational & machinery perspective to avoid any exposure, machinery failure or future consequence effect from continual usage. The effect of high nitrogen cargoes on LNG industry Capt. Anthimos-Alexios Pippos Port Captain
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