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In-depth | CHINA NEWS


FEATURE THEME Inland Navigation in a clean energy era


A representative of the International Shipping Federation said at a recent conference (in China) that the country “stands at the forefront in using natural gas as a bunker fuel.” Te application of LNG in the country’s inland water transport has raised awareness of alternative fuels, but what is the current situation, asks Liu Ying of China Ship News?


T


he economic and environmental advantages of LNG as a bunker fuel are obvious. It is understood


that for hybrid vessels that use both LNG and diesel, the diesel replacement by natural gas can reach around 70%, bringing economic and environmental benefits. According to statistics, dual-fuel engines’ sulphur oxide and particulate emissions are 70% lower, nitrogen oxide emissions are 35-40% lower, and CO2


emissions are


20-28% lower. Additionally, LNG has a strong price advantage when compared to diesel. In China, the price of diesel exceeded Rmb8000/tonne (US$1270/tonne) (at the time when this article was written), while natural gas cost about Rmb5000/tonne (US$794/tonne). Using LNG can reduce bunker costs by 25% based on market prices (when this article was written). On the technical side, natural gas is more


suitable for ships (compared to diesel). Its advantages include a higher compression ratio – the compression ratio of LNG is as high as 625, allowing a larger storage volume in a single unit. Also, natural gas is easy to store – gas can be stored in containers for 30 days under normal temperature, based on experiences from usage on land. On top of that, the engines of existing inland river vessels can combust natural gas with suitable conversion, such as installing ECU (Electronic Control Unit). More importantly, it is safe to use natural gas. LNG, as a cryogenic fluid, vaporises quickly once there is a leakage. It is less dense than air, therefore, it will move upwards without polluting the water table. The flashpoint for LNG is higher than that of diesel, and LNG is easy to diffuse, therefore, it does not explode easily. Te use of gas has become more popular


in river transport in China in recent years because of the advantages mentioned above. A number of dual-fuel vessel conversion


18


A Yangtze vessel fitted with LNG fuel containers.


projects have been completed, bringing social and economic benefits as well as experiences. In August 2010, China achieved a major technical breakthrough in diesel- to-LNG ship conversion as the trial launch of its first dual-fuel vessel No.302 ferry was carried out. The trial launch of another hybrid LNG-diesel vessel SUSUHUO 1260 was also held successfully in the SuBei part of the Grand Canal (Jing Hang Canal) at around the same time. SUSUHUO 1260 has started operations since then. In March 2011, China Changjiang National Shipping (Group) Corporation’s ChangXun No.3 was converted into the first bulk carrier with a dual-fuel propeller system running on the Yangtze River. According to the experts from the


China Classification Society (CCS), the conversion of No.302 ferry and ChangXun No.3 include the installation of the LNG supply system which comprises of a LNG gas-tank, vaporiser, pipe system and valve fittings. No.302 ferry was installed with four


0.5m3 was equipped with two 3m3


LNG tanks, while ChangXun No.3 LNG tanks. Te


vessels’ engines have also been retrofitted: a gas fuel system was added into the inlet gas pipe of the engines; safety valves were added to the engines inlet and outlet gas pipe and crank shaſt case; the gas storage tank and living area were retrofitted in order to satisfy fire structural requirements; inflammable gas detectors were installed in the engine room; mechanical ventilation of the engine room was upgraded by increasing its ventilation rate in order to satisfy the ventilation requirement; a water mist system and dry powder fire suppression system were added etc. Te trial launches of the vessels have shown that existing river vessels can be converted to use natural gas to achieve better results in energy saving and emission reduction.


Multi-party cooperation sends LNG onboard LNG vessel conversion projects in


The Naval Architect March 2012


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