Recovered thermoplastic plastics are generally recycled into plastic oil after being re-polymerized and pyrolyzed. However, foaming polystyrene drifting in the ocean or off the coast contains salt that adhered while drifting in the ocean for a long period of time because seawater can enter the inside of foaming polystyrene from damaged or cracked parts. This salt content generates hydrochloric acid gas during combustion and corrodes combustion equipment and piping when polystyrene expanded with seawater is reused as thermal decomposition oil or solid fuel. Therefore, these recycled products cannot be used due to salt contained in the material.
From the cost-saving perspective, we have proposed the development of a desalination and volume reduction device for foaming polystyrene. In this research, we investigated how much foamed polystyrene could be desalted and reduced in size by using oil bath. This attempt was intended to obtain necessary design data to develop a practical device. As a result, we could specify the optimum temperature for volume reduction and confirmed that salt concentrations in the samples were greatly reduced after foaming polystyrene that had drifted in seawater was reduced.
The design philosophy of the new model Z-PELLER aimed at both high thrust (Bollard Pull) and lightweight. The high thrust requires a strengthened power transmission system that inevitably leads to an increasing in size. Practically, it may not be compatible with both two performances due to the trade-off relationship between them.
Although the FEM-based optimization for an individual part design to balance the conflicting requirement may be effective, currently, it is still insufficient to analyze a whole model assembled intricately since the undetermined boundary conditions and the appropriate numerical solution is hard to obtain yet. Thus, an adequacy method should be introduced to evaluate beyond the conventional conditions and the newly adopted consideration.
In this paper, we introduce the load test facility developed by NIIGATA and the result of the actual load test by using this equipment.
At a meeting of IMO’s Marine Environment Protection Committee (MEPC) held in October 2016, a decision was reached to tighten regulations on the sulfur content of marine fuels in all waters of the world, except designated “emission control areas” (ECAs), from the current 3.5% limit to less than 0.5% starting on January 1, 2020. Under the International Convention for the Prevention of Pollution from Ships (MARPOL), state parties to the convention are allowed, in lieu of using marine oil with sulfur content below 0.5%, to use marine fuel with a sulfur content of 3.5% on ships that are equipped with systems of equivalent efficiency as confirmed by the supervisory authority of the party to the convention.
Mitsubishi Heavy Industries, Ltd. and Mitsubishi Kakoki Kaisha, Ltd. jointly developed an Exhaust Gas Cleaning System for marine applications that efficiently removes sulfur oxides (SOx) from exhaust gas emitted by marine diesel engines. The system was officially approved by Nippon Kaiji Kyokai (Class NK) as an alternative method for compliance with Regulation 14 of MARPOL AnnexⅥ on behalf of Panamanian Administration.
Lean-burn gas engines contribute to CO2 reduction, and exhaust gas from these engines emit low levels of NOx, SOx and smoke, but it has the problem of methane slip. In contrast, exhaust gas from diesel engines has a small amount of methane, but contains a large volume of NOx. The use of EGR that utilizes exhaust gas from gas engines for marine diesel engines may serve to reduce NOx and methane emissions simultaneously.
The authors investigated possible effects of EGR that uses exhaust gas from the gas engine together with emulsion fuel and fuel injection control on emission characteristics of the marine diesel engine. The results showed that while NOx emission was greatly reduced with EGR, the amount of produced smoke increased. When the engine load was 75 percent, the use of emulsion fuel worked to reduce the volume of smoke, but when the load was slashed to 25%, more smoke was produced. We found that pre-injection was effective to address these problems at the same time. We also confirmed that the system cut down methane emission by 75% to 90%.