TS-53
Assessment and Treatment for Harmful Exhaust Emissions from Marine Diesel Engines
Sumito NISHIO, Yoshio TAKASUGI, Magoshiro KUWABARA, Eiko ISHIMURA, Yasuharu NAKAJIMA, Jie ZHANG, Masaaki KIKUCHI
ABSTRACT
From the viewpoint of global environment protection, regulations for prevention of air pollution caused by ships have been discussed in the International Maritime Organization (IMO) and the regulations on oxides of nitrogen (NOx) and oxides of sulphur(SOx) are expected to put in force in the near future.
And global warming has recently been in such a serious problem that it is necessary to reduce greenhouse gas emissions. CO2 and nitrous oxide (N2O) in exhaust gas contribute to global warming.
In addition to the above, IMO will revise the regulations every five years. Then emission will be expected to be applied to other air pollutants in the near future.
Under these circumstances, we studied effect of fuel property on harmful exhaust emissions from a 4-stroke diesel engine with various marine residual fuels. And we studied the effective techniques such as water-emulsified fuel, the selective catalytic reduction(SCR)system and the electronically controlled hydraulic system for fuel injection and inlet/exhaust valve actuation to reduce harmful exhaust emissions.
This paper outlines the researches done by our diesel engine section in Ship Research Institute to reduce harmful exhaust emissions of marine engines.
Key Words: Diesel Engine, Air Pollution, Fuel, Emulsified Fuel, Selective Catalytic Reduction, Electronically Controlled System
1. INTRODUCTION
Now, global environment problems such as acid rain and global warming are getting serious problems all over the world. The addition of Annex VI specifying the prevention of air pollution to MARPOL Convention was adapted in the International Maritime Organization(IMO). This led the farst international regulation to prevent air pollution from ships. NOx regulation is applied to the ships which are made after January 2000, though the regulation isn't put in force yet because of delay of each country's ratification. The regulation this time can be coped with by the adjustment of the engine, but this regulated value is reviewed for every five years, and it is expected that this regulation becomes more and more stringent.
The global warming presents a serious problem, and it is an important issue to reduce the emission of the cause substances. The cause substances for global warming to be discharged from marine engines include CO2 and N2O. For N2O, even its actual situation can not be grasped now on how much N2O is discharged from marine engines using heavy oil for tile fuel.
Under these circumstances, we studied effect of fuel property on harmful exhaust emissions from a 4-stroke diesel engine with various marine residual fuels. And we studied the effective techniques such as water-emulsified fuel, the selective catalytic reduction (SCR) system and the electronically controlled hydraulic system for fuel injection and inlet/exhaust valve actuation to reduce harmful exhaust emissions.
This paper outlines the researches done by our diesel engine section in Ship Research Institute to reduce harmful exhaust emissions of marine engines.
2. FUEL PROPERTY ON HARMFUL EXHAUST EMISSIONS
The range of marine fuels properties are very wide because they are generally made of very variety of residual fuels. Then even if we use same diesel engine, diesel combustion and exhaust gas emissions from it are very changed by marine fuel used. Therefore, influence of fuel properties on combustion and emissions was investigated by the burning test of various marine residual fuels on a medium speed marine diesel engine.
2.1 Test Apparatus and Method
2.1.1 Test engine
The test engine used in this test is the medium speed 4-cycle engine of 257 kW(350 PS)/420 rpm in maximum continuous output, and its principal particulars are shown in Table 1. Though the engine is manufactured with the specification of using Marine Diesel Fuel(MDF), its fuel system is remodeled so as to heat the fuel to realize the operation with Marine Fuel Oil(MFO). Also, in order to examine the combustion characteristic and the fuel injection characteristic, detectors for the in-cylinder pressure, the fuel injection pressure and the lift of the fuel injection needle valve are mounted thereon.
Ship Research Institute
6-38-1 Shinkawa, Mitaka, Tokyo 181-0004 JAPAN
FAX: +81-81-422-41-3101, E-mail: nishio@srimot.go.jp
