Lubricating oil refining process
AssigneeMobil Oil Corporation
InventorDouglas J. Gammie, II
Life of this patent
Estimating the term…
Abstract
Thermal degradation of furfural in solvent refining of lubricating oil stocks is reduced by use of a thin-film evaporator for the final stages of furfural recovery, permitting increased pressure to be used in each stage of furfural recovery.
Claims15
A process for removal of an aromatic rich fraction from a lubricating oil stock fraction comprising:
- furfural extraction of said oil chargestock in a furfural aromatics extraction means operating at furfural extraction conditions to dissolve said aromatic rich fraction in furfural to produce a raffinate phase containing lubricating oil stock and a furfural extract phase containing said aromatics rich fraction;
- heating said furfural extract phase at a pressure less than about 50 psig by indirect heat exchange with a higher pressure vaporized furfural stream to produce heated extract;
- flashing said heated extract in a low pressure flash vessel operating at a pressure less than 50 psig to produce a low pressure furfural vapor phase and a low pressure flash liquid phase containing furfural solvent and aromatics which is removed from said vessel;
- heating, and simultaneously vaporizing, at least a portion of said low pressure flash liquid phase by indirect heat exchange in a thin-film evaporator to produce an aromatic rich liquid phase product with a reduced furfural content and vaporized furfural;
- and
- cooling and condensing said vaporized furfural to produce liquid furfural;
- and
- recycling said liquid furfural to said liquid/liquid aromatics extraction means.
A multi-stage process for recovering furfural solvent from a feed liquid stream comprising hydrocarbons boiling within the range of 600.degree. to 1000.degree. F. and furfural present in an amount equal to at least 10 moles of furfural per mole of hydrocarbon, comprising:
- a. heating said feed liquid stream by indirect heat exchange with a higher pressure vaporized furfural stream to produce a heated liquid stream;
- b. flashing said heated feed liquid stream in a low pressure flash vessel operating at a pressure below 50 psig to produce a low pressure furfural vapor phase and a low pressure flash liquid phase containing furfural solvent which are removed from said vessel;
- c. pumping said low pressure flash liquid phase to produce a pumped liquid stream having a higher pressure;
- d. heating said pumped liquid by indirect heat exchange with a vaporized furfural stream to produce a heated pumped liquid stream;
- e. flashing said heated pumped liquid in at least one high pressure flash vessel operating at a pressure above said low pressure flash vessel to produce a high pressure furfural vapor phase and a high pressure liquid phase;
- f. cooling and condensing at least a portion of said high pressure furfural vapor phase by indirect heat exchange with said feed liquid stream to produce a liquid furfural solvent product stream;
- g. evaporating additional amounts of furfural from said high pressure liquid phase by indirect heat exchange in a thin film evaporator to produce a hydrocarbon liquid product containing a reduced amount of furfural and a furfural vapor product.
A multi-stage process for recovering furfural solvent from a feed liquid stream comprising hydrocarbons boiling within the range of 600.degree. to 1000.degree. F. and furfural present in an amount equal to at least 10 moles of furfural per mole of hydrocarbon, comprising:
- a. heating said feed liquid stream by indirect heat exchange with a higher pressure vaporized furfural stream to produce a heated liquid stream;
- b. flashing said heated feed liquid stream in a low pressure flash vessel operating at a pressure below 50 psig to produce a low pressure furfural vapor phase and a low pressure flash liquid phase containing furfural solvent which are removed from said vessel;
- c. pumping said low pressure flash liquid phase to produce a pumped liquid stream having at least 5 psi higher pressure;
- d. heating said pumped liquid by indirect heat exchange with a vaporized furfural stream having a pressure at least 5 psi higher than the pressure of said pumped liquid to produce a heated pumped liquid stream;
- e. flashing said heated pumped liquid in at least one high pressure flash vessel operating at a pressure at least 5 psi above said low pressure flash vessel to produce a high pressure furfural vapor phase and a high pressure liquid phase;
- f. cooling and condensing at least a portion of said high pressure furfural vapor phase by indirect heat exchange with said feed liquid stream to produce a liquid furfural solvent product stream;
- g. evaporating additional amounts of furfural from said high pressure liquid phase by indirect heat exchange in a thin film evaporator to produce a hydrocarbon liquid product containing a reduced amount of furfural and a furfural vapor product.
Dependencies are inferred from the claim text.