Mitsui Engineering & Shipping Co., Ltd. has been carrying out research and development for utilizing various kind of off spec. fuels as fuel for diesel engines with the objective of diversifying fuel and sources, and putting inexpensive fuels to practical use. As the fuels deviate from the specifications of marine fuels, they are called off spec. fuel.
This paper deals with straight vacuum residue, visbreaker residue, and Orimulsion® of the off spec. fuels investigated by Mitsui until now. The characteristics of the fuels, and performance, exhaust emissions and durability of a diesel engine in the case of using the fuels are described in this paper. All of the three off spec. fuels can be used in 2-stroke cross-head diesel engines, although the same grade of clarification as that for marine fuel oils, using a fuel which has lower viscosity and campatibility with the fuels for changeover at starting and stopping engines, heating up the fuels for controlling their viscosity below 20 mm
2/s (20 cSt), etc., are indispensable.
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