Further, the content of content of water, unburnt oil and metals (vanadium, etc.) of other components is relatively low.
3] As for the difference in the components by part of deposit of the residue, it is recognized that the calcium content is apt to decrease from the combustion chamber to the downstream side of the exhaust gas pipe, while the carbon content becomes higher from the combustion chamber to the downstream of the exhaust gas pipe.
5.2 Classification of Residues and Thermal Analysis
1] The residue can be roughly classified into "calcium type： Ca type" and "carbon type： C type" through the analysis on the components of the combustion residue, and further classified into three groups in which the "intermediate type" is added through thermal analysis (TG/DTA). The classification of the residue through thermal analysis is performed based on the content of solid carbon, and there is a tendency that a small amount of unburnt oil caused by insufficient combustion is contained in C type residue.
2] Main engine residue changes from Ca type to C type from the combustion chamber to the exhaust gas economizer.
3] Application of the thermal analysis to the residue is extremely effective as a means of estimating the combustion condition in the combustion chamber, and it is recognized that the thermal analysis is appropriate for estimating combustion troubles and insufficient combustion attributable to the fuel oil with solid carbon (and the unburnt oil part) as the index.
Discussions：
Questioner： Kenji Goto
[Question]
*Even in cases where the combustion seems excellent (a small amount of soot is adhered in the vicinity of the piston - T/C), there is one case where the soot adheres to the exhaust gas economizer and one case where no soot adheres to the exhaust gas economizer. Do you have any idea where the difference (what the cause) is.
[Answer]
As for the adhesion of soot to the exhaust gas economizer, there are factors which can not be judged only by the condition of the combustion chamber, and it is believed that related parameters (design, structure, maintenance, operation, etc.) affect each other.
In the analysis results of this examination, the carbon type residue is poor at bonding, while the calcium type residue is hard, and calcium salt is bonded in the highly humid atmosphere, or solidified at high temperature. It is believed that such a difference in the nature of the major components affects the adhesion of the soot in the exhaust gas economizer.
Further, in the subsequent examination, the relationship between the combustion residue and the properties of the fuel oil is also examined. Among them, there is a tendency for the carbon type residue is to be generated easily as the aromatic component in the fuel oil is increased (as the paraffin component becomes smaller), and as the properties of the fuel oil are largely different according to the supplied oil. That means, it is considered that the soot content in the exhaust gas economizer is affected by the properties of the fuel oil used.
The deposits of the residue which were not examined this time will be examined in the future.
References
(1) Konishi, S., and Kamita, T.,"Principle and Application to Lubricating Oil", Publisher "Corona-sha", (1992)(IBN4-339-04311-7)
(2) Awai, N., Hanashima, O., and Yokozawa, S., "Fuel Oils used for medium & large size marine and land use diesel engines - Methods of usage of low quality fuel oils and effects for air pollution", Publisher "Sankaido" (1994)(ISBN4-381-10060-3-C3053)
(3) Fujiwara, Y., "Process for Diesel Paticulate Formation",(Journal of The Japan Petroleum Institute, Vol.5,255〜266,1990)
