FIELD: chemistry.
SUBSTANCE: method of obtaining petroleum ethers includes separation of initial hydrocarbon raw material into fractions by rectification, with petroleum with boiling out temperature from 40 to 120°C and content of aromatic hydrocarbons to 5 wt % being used as initial raw material. Rectification is carried out in three successive stages. At the first stage initial hydrocarbon raw material is purified from insoluble and suspended admixtures, resins, asphaltenes in apparatus of semi-continuous distillation with continuous supply of initial hydrocarbon raw material into complete evaporation still with constant level, still mixing device with scrapers to prevent fouling of still tank walls, reflux condenser - splash-settler, representing column - ring, filled with attachment - Raschig rings, condenser-refrigerator with descending steam flow for condensation and cooling of condensate, tank for reception of finished product, with discharge of bottom residue being carried out periodically when necessary. Distillate, obtained in a apparatus of semi-continuous distillation, is supplied from it into distillate tank, and from the latter into installation of preliminary rectification, representing apparatus of periodic rectification, made of stainless steel, consisting of still tank, filled from distillate tank of apparatus of semi-continuous distillation, rectification column, filled with attachment in particular Raschig, Pall rings, with ratio of average size of attachment to column diameter not less than 10, the latter is used to carry out fractioning of distillate which has been supplied into it with obtaining fractions in temperature ranges to 40°C, 40-70°C, 70-100°C, 100-120°C and higher than 120°C. Obtained fractions are supplied into tanks for accumulation of separate fractions and homogenising-recovery tank for accumulation of fractions, which are not intended for supplying to the following stage, and filling all tanks: accumulation of separate fractions and homogenising-recovery fraction is realised by gravity flow. After that separate fractions are supplied into installation of accurate rectification, which represents apparatus of periodic rectification, made from stainless steel, consisting of still tank, filled from tanks of accumulation of separate fractions, and rectification column, filled with attachment, in particular Raschig, Pall rings, with ratio of attachment element dimension to column diameter not less than 12. The latter is used to obtain solvent stripper, which is supplied into tank for solvent stripper accumulation, and finished product, which is supplied into tanks for target fractions and further to homogenising-packing tanks for accumulation of finished product.
EFFECT: method makes it possible to obtain petroleum ether fractions f the following purity: pure, pure for analysis, chemically pure, with special purity.
