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Up to now gas oil and Bunker A of good quality have been used for the fuel oil of fisheries engine. But as the quantity of buried petroleum is set limits, the oil price is raised and light oil is restrained. So imferior crude oil is imported and according to the increase of spending light fraction, the heavy oil is getting poor grade because much light fraction being put out. And so the quantity of heavy oil got from crude oil now decreased to 15% from 45%, on the contrary viscosity and specific gravity of the oil is raised, and sulpher, asphalt, B,S,W and sludge being enriched heavy oil has been and only for low speed multi-diesel engine because it is difficult for the tranfer, purify, injection and combustion. But in the furture as the specification of fuel oil is greatly getting low residual oil can not be used for fisheries engine. I here confirm that blend oil can be used in summer by the experiment of blend oil (D1, D2, D3) for high speed diesel engine. The result is as follows. 1.in case that recidual quality is great, the range of the use of r.p.m is narrowed and low speed operation is difficult. 2.According as recidual quality is greater at the same number of rotation fuel consumption is increased, but fuel cost is saved at above 900 r.p.m which comes under 1/8 load. 3.Combustion pressure is showed high by after burning owing to the combustion obstacle of recidual quantity. 4.Exhaust temperature is increased to 9℃ in D1, 13℃ in D2, 23℃ in D3 and cooling water temperature is decreased to 2.7℃ D1, 2.9℃ in D2 and D3.
In general, the efficiency of boiler varies with the loading rate, season and the operated year. When the boiler is operated in accordance with the maximum efficiency, it can be possible to save energy. In this experiment, the operating data of three boilers (two-drum D-type water tube boiler, capacity 30t/h, steam pressure 7.5 kg/cm2) were checked and calculated in order to know the amounts of evaporation and consumption of fuel oil, temperature (feed water, fuel oil, exhaust gas and air), the CO2%, the loss of exhaust gas and the calculated boiler efficiency. For the purposes of this study, the boilers were operated and six times checked with 45-100% of the loading rate in summer from 15th of July to 14th of August and in winter from 15th of December to 14th of january in the next for three years. The main results obtained from this study are as follows: 1.The maximum efficiency of boiler was decreased by 0.63% in summer and by 0.49% in winter in a year. 2.The average maximum efficiency of boiler was higher by 1.73% in summer (average 90.49%) than in winter (average 88.76%). 3.The economical loading rates showed 75% in summer and 80% in winter by No. 1 boiler, 85% in summer and winter by No. 2 boiler and 75% in summer and 80% in winter by No. 3 boiler. 4.The total average boiler efficiency with respect to 45-100% of the loading rate was higher by 1.39% in summer (87.84%) than in winter (86.45%). 5.The average temperature of exhaust gas was higher by 12.35℃ in winter (158.28℃) than in summer (145.93℃). 6.The average loss of exhaust gas was higher by 1.13% in winter (6.01%) than in summer (4.88%). 7.When No. 1 boiler was operated on the loading rate in accordance with the maximum efficiency, the fuel cost was down by 2,1000,000 won/ month in summer and 1.080,000 won/month in winter in comparison with± 5% of that condition.