PROCEDURE FOR "DRY" PROPANE DE-ASPHALTISATION OF OIL RESIDUES Russian patent published in 2011 - IPC C10G21/14 C10G21/28 

FIELD: gas and oil production.

SUBSTANCE: raw stock is mixed with propane before extractor and mixture is cooled, which corresponds to removal of extraction zone from process vessel and utilisation of its whole height for increased quality of asphalt-free oil. Raw stock with propane mixture cooling facilitates transition to low temperature mode of extraction when dissolving capacity of propane grows. Propane is regenerated from solution of asphalt-free oil till pressure drop in a system of propane condensation according to a traditional process, but further, solution of asphalt-free oil from the last evaporator of propane is directed to a furnace for heating to temperature ensuring approximately equal value of product (ki-1)Mi; where Mi are molecular weights of obtained products (asphalt-free oil or asphalt), while ki is constant of equilibrium of propane at various temperature of their heating in the furnace and different pressure of separation of propane (from asphalt - at pressure in the system of propane condensation, from asphalt-free oil - at pressure in a steam-stripping column) whereat removal of propane residues in the steam stripping columns is facilitated even without supply of steam into them. At absence of moisture in the system of propane condensation hydrogen sulphide, indispensably produced during products heating in the furnace, is transformed into inert gas with molecular weight closer to ethane, than to propane. Consequently, it is easily blown off from a working vessel of propane (with methane and ethane).

EFFECT: application of procedure of "dry" propane de-asphaltisation not only at oil, but at fuel production, which increases depth of oil processing.