The dual fuel engine and generator can meet the requirements of International Maritime Organization (IMO) for the emission of nitrogen oxides and sulfide, and can reduce the emission of carbon dioxide and particulate matter, when using the liquefied natural gas (LNG), a clean energy source, as fuel. The objective of the current study on the application of the fuel gas supply system is how to ensure the safe use of LNG as fuel, which is also the main requirement of the International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk(IGC Code). This paper introduces the design of a set of fuel gas supply systems for a LNG bunker vessel with one main engine and two generators. The main gas valve design, ventilation flow calculation and dangerous region setting that are required in the IGC Code are calculated, studied and analyzed. The design requirements of one main valve for several devices in the fuel gas supply system that meets the IGC Code is summarized. The optimized system design can meet the requirements of the ICG Code for the safe use of LNG fuel.

Affected by the global warming, resource crisis and trade protectionism, energy conservation and consumption reduction, transformation and upgrading, and innovation and development are the only way for the development of the shipping industry. The International Maritime Organization (IMO) launched the ship energy efficiency design index (EEDI), which came into effect on January 1, 2013. The entry into force of this resolution has a large impact on the selection of the power point of the ship main engine. Operators have chosen to reduce the power of the main engine to meet the EEDI requirements. However, the acceleration performance of the main engine will be significantly reduced when it is operated with the reduced power. Therefore, the barred speed range (BSR) cannot be passed through quickly, resulting the great threat to the safety of the shafting. A theoretical analysis of the decrease of the acceleration performance has been carried out for the main engine at the BSR to find solutions from the main engine control system, propeller design and shafting design. The results are finally verified with the calculated results that the ship can meet the requirements of the various classification societies while operating safely and stably.