Technical Papers
Study on the Operational Results of a Marine Diesel Engine Using Water Emulsified Fuel from the Marine Engineer's Aspect*
by Satoshi Yamamoto** Itirou Kanda**
The marine diesel engine using water emulsified fuel was operated in a diesel engine plant for the electric generator on Training Ship "Nippon Maru".
This practical operation was carried out 2,063 hours of total running.
However, several problems such as the lack of response performance to rapid increase of electric load and difficulty in disposal of leaked emulsified fuel from fuel injection system, occurred in this operation.
Further more, the influence of emulsified fuel to the constituent parts of diesel engine was investigated when it was overhauled and the followings were found:
1) On the case of using emulsified fuel, the opening pressure of injection valve lowered always in comparison with using marine diesel fuel.
2) Slight abnormal wear was observed at the fuel injection nozzle and pump plunger.
3) Glassy white deposit and wrinkled traces which were caused by the water contained contained in emulsified fuel were found on the piston head.
1. Introduction
Countermeasures on the environmental disruption issues on the global basis have been discussed earnestly, and new regulations are specified on the air pollution caused by the exhaust gas from ships by the IMO (International Maritime Organization) similar to the regulations on the marine pollution. Regarding the emission of nitrogen oxides (hereinafter, referred to as NOx) to be restricted by the regulations, the technology for reducing the emission has been developed actively toward 2000 in which the regulations will substantially come into force.
A variety of the NOx reducing methods are available including a method of the laminated water injection system which was jointly studied with the Institute for Sea Training (hereinafter, referred to as "Institute") of the Ministry of Transport on board the Training Ship "Ginga Maru" in the past. At the same time, the system in which the water emulsified fuel (hereinafter, referred to as emulsified fuel) with water diffused in fuel oil is burned, has also been developed, and many reports were made on the results of the tests on the shore. Since no verification studies have been made on board ships, and the verification was made on board the Training Ship "Nippon Maru" of the Institute, in which the emulsified fuel manufacturing device is mounted on the diesel engine for the electric generator No.3 (the medium speed marine diesel engine, hereinafter, referred to as "diesel engine").
2. Test apparatus
2.1 Particulars of diesel engine and electric generator
Table 1 shows the particulars of the diesel engine and the electric generator.
2.2 Emulsified fuel manufacturing device
The SEKIEMAR SP300A (manufactured by Sekiguchi) was used to manufacture the emulsified fuel. This device comprises 1] a mixing unit, 2] a proportional water pouring unit, 3] an additive pouring unit. 4] a supplementary water tank, 5] control panel unit, etc. Fig.1 shows the piping diagram after attachment to the fuel oil system.
The excessive fuel generated during the normal operation is returned to the A-oil service tank. When the A-oil is changed to the emulsified fuel during the test, the piping is changed to be returned to the suction side of the FO booster pump so that the emulsified fuel is not mixed in the A-oil service tank. Only this part is additionally changed in the piping for the test.
2.3 Test method
The test was carried out during the training navigation of about one year including the ocean navigation to Hawaii islands over two months with the actual facilities while the modification of the diesel engine side was limited to only a part of the fuel piping. The total running time using the emulsified fuel was 2,063 hours.
* Translated form Journal of MESJ vol.35, No.1 (Manuscript Received May 14, 1999)
** Institute for Sea Training (Kitanakadoori Naka-ku Yokohama)
