Heating mazut
Mazut is a kind of oil fuel used as a boiler fuel in power engineering, navigation and industry. Heating mazut is used as a boiler fuel for various thermal generators, as a principal source of thermal energy in heating systems, in boilers. Boiler fuels include heating mazuts grades 40 and 100. Technical conditions for heating mazuts are regulated by GOST 10585-99.The furnace oil is intended for burning in heating installations of small capacity located immediately in the premises, and also in heat generators of average capacity used in agriculture for the preparation of forages, drying of grain, fruits, the conservation and for other purposes.
The requirements in force to the quality of boiler, heavy motor and navigation fuels, establishing conditions of their use, are determined by such parameters of quality, as the viscosity, sulfur content, combustion heat, solidification temperature and flash temperature, water content, mechanical impurity content and ash content.
The GOST 10585-99 standard for boiler fuel provides for the production of four of its grades: naval mazuts F-5 and F-12 which by viscosity are classified as light fuels, heating mazuts grades 40 - as an average and grade 100 - as low-volatility fuel. The figures roughly indicate the viscosity of corresponding grades of mazuts at 50 °С.
Heating mazuts grades 40 and 100 are produced out of oil refining residues. To decrease temperature of solidification down to 10 °С, 8-15 % mazuts of medium distillate fractions are added to grade 40 mazut, whereas diesel fractions are not added to mazut grade 100. Naval mazuts grades F-5 and F-12 are intended for burning in marine power installations. Compared with heating mazuts grades 40 and 100 they possess better characteristics: the lesser viscosity, content of mechanical impurities and water, ash content and the lower temperature of solidification.
Naval mazut grade F-5 is obtained by mixing of products of straight distillation of oil: in most cases 60-70 % of straight run mazut and 30-40 % of diesel fuel with addition of depressant additives. It is acceptable to use in its composition up to 22 % of nafta-gasoil fractions of secondary processes, including the light catalytic gasoil and that of thermal cracking. Naval mazuts grade F-12 are produced in small amounts on installations of straight distillation of oil. The main differences of mazuts F-12 from F-5 are the more strict requirements for sulfur content (0.6 % against 2.0 %) and less strict requirements for viscosity at 50 °С (12° relative viscosity against 5° relative viscosity).