Distillate marine fuel consisting of lighter fractions obtained by distillation installations for oil refining, are characterized by low viscosity, v = 3 h-6 mm2 / s, so do not require heating before serving to engines or boilers. Heavy Marine Fuels are a mixture consisting of the residual products of petroleum and distillates. Depending on the balance of light and heavy components viscosity of heavy marine fuels, as well as their other indicators, varies considerably. In Russia, the quality of marine fuels are regulated by state standards and specifications. Abroad, the quality of marine fuels specifications determined supplier firms of British (BS 2869: 1967) and American (A5> TM-D975 and D396-67). Began in the 70s and more distributed process involving the production of ship fuel oil products recycling demanded revision existing standards and specifications, the expansion of the limit values of quality and attraction of additional indicators (such as the aluminum content, stability and compatibility of fuels, etc.). Distillate marine fuel Due to limited resources and high value distillates, diesel marine fuel – referring to the class of spirits, in the USSR, approximately 1.7 times the cost of heavy marine fuels.
Consumption of marine diesel fuel to Navy ships is only 6-12% of the total amount of fuel burned. Its mainly used to support medium-and high-speed diesel engines, that either by design or because of unsuitability of toplivopodgotovki (no heat) can not be translated into a more severe marine fuel. In the main engines of ships ship diesel fuel used exclusively during the maneuvers, and for flushing the fuel system before stopping. The domestic industry produces marine diesel fuel in accordance with GOST 305-82 by mixing fractions of direct distillation of sulfur crudes, hydrotreating and dewaxing the past, with a catalytic gas oil. The presence of a catalytic gas oil, reduces the operational properties of fuels, in particular increasing its propensity for deposition. Marine fuel produced four grades: A, 3, AP, A, which is on the sulfur content is divided into two subgroups: with S%, with S == 0,21 – 0,5%.
The content of mercaptan sulfur in the sulfur of both subgroups is limited to 0.01%. As replacement marine diesel fuel in ships of sea and river vessels are widely used gas turbine fuel (GOST 10433-75). Fuel is obtained as a byproduct in the process of delayed coking unit in the development of petroleum coke, metallurgical industry required. Gas turbine fuel and TG TGVK have a higher density and viscosity, but not so high that they had to warm up before use. For these fuels have a higher sulfur content (1 and 2.5% respectively), and what should be paid attention to particular, they contain up to 25% tar. This leads to their low stability, manifests itself when heated and mixed with other fuels. Since 1988, the oil industry began to supply the navy ship's low-viscosity oil designed to replace diesel and gas turbine fuels. It produce fuel by mixing the distillate of secondary processes (coking, thermal and catalytic cracking) of diesel fractions with a high end boiling point, taken from the atmospheric and vacuum columns. On Compared with the ship's diesel fuel to it less stringent requirements (may be twice as high viscosity, 11 mm2 / s, the sulfur content to 1.5%, lower TSCH – not less than 40).