Ships usually end up their life by scrapping. Nowadays most of them are treated in India or Bangladesh where HSE and pollution related problems are broadly discussed in public. The United Nations, IMO, ILO, International Chamber of Shipping and NGOs, etc. are working to establish and organize an effective international framework for ship recycling. This paper introduces history, background, current status and prospects for the near future regarding ship recycling as well as activities and service portfolio of Det Norske Veritas AS (DNV) .
Consumption of residual fuel oil in the main boiler of LNG tankers has been increasing due to a change in the design of BOR of the LNG tank or the use of a BOG re-liquefier. As a result, the ash part (Vanadium, etc.) in the residual fuel oil has also been increasing. These conditions make it easy to generate large quantities of fuel ash with a low melting point. The melt ash causes damages like sticking deposits, corrosion, etc. in the furnace and the superheater tube. This report is intended to investigate a plan to prevent the above mentioned damage of the main boiler of LNG tankers by fuel oil additive. The results of the comparison of fuel oil additive are as follows: (1) As a result of having compared Si type additive with Mg type additive, Si type was confirmed to have a better effect on raising a softening point of V, Na compound in the range of 300-500 degrees Celsius than Mg type. (2) Si type additive inhibits high temperature corrosion in the same way as the Mg type additive. (3) When Si type additive is added to fuel oil with 1.2-3.6 times of the V, Na gross weight, the adhesion inhibition rates of fuel ash decrease by 30-70%. These effects will be able to maintain high thermal efficiency and longer safe operation of the main boiler.
With the increasing demands for energy resources, hydrocarbon development is expanding its field to what is called frontiers, including ice-covered waters. Surface transportation by tankers in ice plays an important role as a major transportation mode of the developed resources to and from the refmery and/or to the market. On the other hand, ice-covered waters are known to be vulnerable to pollution. Large oil spilling by a tanker accident could cause irretrievable damage to the environment. Oil spilling response in ice, however, requires totally different technologies from those in open water conditions. For the sustainable development of resources in ice-covered waters it is indispensable to secure shipping safety and prepare a proper response system against pollution due to oil spilling.
First successful gas engine was the Lenoir atmosphere gas engine, which was invented around 1860. Since this engine did not use compression, thermal efficiency was very low. Ever since gas engines have had a very long history. However, the authors did not find any papers, which mention the reasons why nitration, deposit formation in combustion chamber and others occur in gas engine although diesel engine does not have any problems in these areas. In this article, those related reasons and also compilation of quality and performance requirements for gas engine oils for better understanding the gas engines were described.
It is possible that the use of methyl-ester as an alternative to diesel fuel could one day solve the problem of increasing CO2 emissions. Particularly, methyl-ester from waste edible oil (MEW) which recycles the oil resource; however, little is known about the effect oxidation and cracking of MEW do to its combustion characteristics. In this study, methyl-esters from MEW and from unused edible oil (MEU) were compared. MEW and MEU have almost the same properties (density, lower calorific value and kinematic viscosity), but ignition temperature of MEW (276 °C) is lower than that of MEU (289 °C) . During the engine performance test (we used a 273cc diesel engine) we measured the cylinder pressure, exhaust gas emission and fuel consumption. Ignition delay of MEW is shorter than that of MEU, and NOx emission of MEW is lower than that of MEU. Smoke emission for MEW and MEU are almost the same.
The petroleum which carries out important role presently as an energy source with the sea is transported with the tanker mainly. But loss of flow accident of the petroleum due to the accident which from around 1960 accompanies the mass transit of the petroleum it to reach the point where it occurs as a time, the marine pollution problem due to that has expanded quickly. There is a crack arrester as one of preventive measures of the brittle fracture in the hull which can become cause of such accident. When the crack arrester by providing the open slot is made to mix it is not avoided that strength of the component decreases, but crack development is controlled, it is thought that it is effective. You verified there is some kind of influence in the component by providing the stiffener where Young's modulus differs to the deep water of the above-mentioned crack arrester in this research making use of the portable finite element method which establishes as a basis on Delaunay automatic element division.
Plate-type heat-exchangers are increasingly being used in the cooling systems of vessels. While these systems have numerous associated benefits, one disadvantage is decreased performance associated with the formation slime on the cooling surface of the heat-exchanger. A new cleaning system for plate-type heat exchangers involving the addition of powder made from insertion scallop shells and air to the cooling water has been developed. Evaluations of slime removal efficiency were shown to be affected by the flow of cooling water, concentration of shell powder, quantity of air injected, washing time, and decreased air-bubble size.
In order to run a numerical analysis of gas-liquid two-phase flows accurately, a three-dimensional computational code has been developed with a new numerical method in consideration of superior mass conservation. In this code, which is based on the GTT code developed by the authors, the interface between two phases is discriminated by an interface tracking function, and the function is reconstructed according to its iso-value surface at appropriate intervals during its convection process so that the interface can be captured sharply and the mass can be absolutely conserved. By using this code with the original numerical method, the behavior of two water droplets, which impinge mutually in various manners, has been numerically analyzed and the calculated result compared with an experimental result. The results show that this code can reproduce well the phenomenon of coalescence or breakup after the mutual impingement of the droplets.