Technical Papers
Investigation Results for Combustion Residue of Marine Diesel Engines*
Toshikazu Takase**, Makoto Yamawaki**, Mitsuo Takahashi**, Takaaki Inoue**, Kiyomasa Shinbori***, Yoshihiko Kon***, Hiroki Oida***
In the present situation, some parts of marine diesel engines are being improved upon. But the combustion chamber and exhaust space, where dust and residue are generated by using poor quality marine fuel oil, are still troublesome factors. And still, some causes of engine troubles have not yet been made clear.
In this investigation, we analyzed the combustion residue which was collected from overhauling the main engine and the generator engine on seven motor ships among those operated by Mitsui O.S.K. Lines.
Then, we investigated the formation of combustion residue.
1. Introduction
The development of long stroke and other improvements have been introduced for low-speed diesel engines for marine use, but the fuel oil is still degraded, and at the present time, the combustion chamber and exhaust gas piping system are adversely affected by the operation of the engine.
In the operation of ship, combustion troubles and damage to the turbocharger and exhaust gas economizer cause not only operational difficulties but also negative factors associated with high cost and labor. It is very important to clean the inside of the exhaust gas piping system at time of engine maintenance. However, not a few items have not yet been clarified even after various examinations have been performed on the causes of engine troubles.
In this paper, the analysis on the combustion residue sampled from the part of the overhauled engine of the objective ships in dry-dock, and the examination of the formation of combustion residue are described.
2. Method of Investigation
Seven ships in dry-dock are selected among those engaged in service, and the combustion residue formed in the main engine and the generator engine, and the fuel oil and the lubricating oil, are sampled for analysis from these objective ships. in addition, the structural members of the combustion engines, etc., is studied by reference to various literatures.
* Translated from Journal of MESJ Vol.33, No.1(Manuscript received Sep.5, 1997)
** Mitsui OSK Line, Ltd.(Ohota-ku Tokyo)
*** Japan Marine Surveyors & Sworn Measurers' Association (Tyuou-ku, Tokyo)
2.1 Objective Ships
Particulars of the objective ships (Ship A 〜 Ship G) are shown in Table 1.
2.2 Test Samples
(1) Combustion residue
The test samples were taken from the parts specified in Table 2 of the objective ships according to the overhaul condition of the equipment when the ships were in dry-dock.
(2) Fuel oil
The test samples were replaced by the analysis data on the fuel oil used by the objective ships in the past two years.
(3) Lubricating oil
The test samples of the main engine cylinder oil and the D/G system oil which were used during this survey period were taken from the storage tanks.
2.3 Items for Analysis
The test samples and the applied analysis items in the survey are as follows.
(1) Combustion residue
1] Composition analysis - Total sample/toluene insolubles
2] PH - Toluene insolubles/aqueous suspension
3] Elemental analysis - Total sample/toluene insolubles
4] Thermal analysis - Total sample (TG/DTA)
5] Metal analysis - Ash→alkali fusion (fluorescent X-ray, ICP, atomic absorption, etc.)
6] X-ray diffraction - Toluene insolubles
7] Layer system - Combustion residue (Scanning electronic microscope/EDX elemental analysis)
8] Gas chromatography analysis - Toluene solubles
