The International Maritime Organization (IMO) has decided to implement a tighter limit for nitrogen oxide (NOx) emissions from ships operating in emission control areas (ECA) from 2016. Hitachi Zosen Corporation has developed a Marine SCR (Selective Catalytic Reduction) system to denitrate exhaust gas of large two-stroke diesel engines in order to comply with the IMO regulation. Nippon Kaiji Kyokai issued a certificate attesting that a large two-stroke diesel engine Hitachi-MAN B&W 6S46MC-C7 with SCR system complies with the NOx emission level required by the IMO regulation. This system was installed on a newly-built vessel, and verification tests were carried out for 2 years. As a result, the development was completed, and MAN Diesel & Turbo issued a certificate of approval for the manufacture and supply of High Pressure-SCR system to Hitachi Zosen Corporation for the first time in the world.
This paper reports on the outline of a marine SCR system, and sea trial results of the marine SCR system which was installed on the newly-built vessel. In addition, current efforts toward commercialization are introduced.
Sealing of contained fluids is the primary criteria required for pipe flange connections. Recently, there is a rapid rate of increase in the use of low temperature fluids, and leakage related accidents have been reported. Its leakage mechanism seems to be different from the case in pipe flange connections at elevated temperatures. In this paper, it is examined how the leakage of low temperature fluids occurs, in which a pipe flange connection is cooled by liquid nitrogen. The variations of bolt temperature and bolt force are continuously measured. Experimental results show that the bolt force is reduced to as low as about 65% of the initial value. Next, a numerical method based on three-dimensional FEM is proposed to simulate the cooling process. Numerical results are in good agreement with those from experiments. Applying the numerical method to the pipe flange connections for LNG, showed a bolt force reduction of 70% of the initial value. The numerical method proposed in this paper is expected to be applied to cases of different low temperature fluids under various flow conditions.
Machine components such as bearings, gears and so on are required to operate under severe tribological conditions such as elastohydrodynamic lubrication (EHL). There have been recent advances in techniques to improve sliding performance using coated films possessing superior tribological properties to reduce machine component failures. These techniques are often used under severe conditions such as elastohydrodynamic lubrication. In this paper, for coated film with interlayer and substrate used under various applied normal loads and entrainment speeds, distributions of oil film pressure, oil film thickness and stress distributions therein were numerically investigated in detail for a point contact under elastohydrodynamic lubrication condition. Also, the effects of applied normal loads and entrainment speeds on distributions of oil film pressure and oil film thickness and stress distributions were discussed. The typical results showed that oil film pressure p and maximum stress σmises-max of material including coated film and interlayer are larger, and that minimum oil film thickness hmin is smaller with increase of oil applied normal load. Maximum oil film pressure pmax, hmin and σmises-max are larger with increase of lubricant entrainment speed.