Diesel

Characteristics of diesel fuel according to GOST 305–82

Main performance indicators of diesel fuel:

• cetane number, which determines high power and economic performance of the engine
• fractional composition that determines the completeness of combustion, smoke and toxicity of engine exhaust gases
• viscosity and density ensuring normal fuel supply, atomization in the combustion chamber and operability of the filtration system
• low-temperature properties that determine the functioning of the power system at negative ambient temperatures and fuel storage conditions
• degree of purity, characterizing the reliability of the operation of coarse and fine filters and the cylinder-piston group of the engine
• flash point, which determines the safety conditions for using fuel in diesel engines
• the presence of sulfur compounds, unsaturated hydrocarbons and metals, which characterize carbon formation, corrosion and wear.

Range, quality and composition of diesel fuels

The oil refining industry produces diesel fuel in accordance with GOST 305-82 of three grades:

L - summer, used at ambient temperatures above 0 °C;

Z - winter, used at temperatures down to -20 °C (in this case, winter diesel fuel must have a stagnation < -35 °C and p < -25 °C), or winter, used at temperatures up to -30 °C, then the fuel should have a stagnation < -45 °C and p A - arctic, the temperature of use of which is up to -50 °C. The sulfur content in diesel fuel of grades L and Z does not exceed 0.2% for type I fuel and 0.5 for type II fuel, and grade A - 0.4%.

To meet the demand for diesel fuel, by agreement with the consumer, the production and use of fuel with a pour point of 0 °C is permitted without standardization of the cloud point. In accordance with GOST 305-82, the following designation of diesel fuel has been adopted: summer fuel is ordered taking into account the sulfur content and flash point (L-0.2-40), winter fuel - taking into account the sulfur content and pour point (Z-0.2- minus 35).

The designation for Arctic diesel fuel includes only the sulfur content: A-0.2. Diesel fuel (GOST 305-82) is produced by compounding straight-run and hydrotreated fractions in ratios that meet the standard requirements for sulfur content. A mixture of middle distillate fractions from direct distillation and secondary processes, most often straight-run diesel fuel and light catalytic cracking gas oil, is often used as a feedstock for hydrotreating. The sulfur content in straight-run fractions, depending on the oil processed, ranges from 0.8-1.0% (for sour oils), and the sulfur content in the hydrotreated component ranges from 0.08 to 0.1%.