초록 ▼

A residuum oil solvent extraction process is improved by using direct fired convection heaters for heating the asphaltene, the solvent-deasphalted oil phase, the deasphalted oil and the stripping steam, instead of hot oil heat exchangers. The convection heaters are fired using recirculated flue gas

A residuum oil solvent extraction process is improved by using direct fired convection heaters for heating the asphaltene, the solvent-deasphalted oil phase, the deasphalted oil and the stripping steam, instead of hot oil heat exchangers. The convection heaters are fired using recirculated flue gas so that the hot flue gas supplied to the convection heaters has a temperature between 800.degree. F. and 1400.degree. F.

대표청구항 ▼

[ I claim:] [1.] In a residuum oil solvent extraction process comprising the steps of 1) contacting residuum oil with a light hydrocarbon solvent at an elevated subcritical pressure and temperature, 2) separating a mixed solvent-deasphalted oil (DAO) phase from an asphaltene phase, 3) heating the as

[ I claim:] [1.] In a residuum oil solvent extraction process comprising the steps of 1) contacting residuum oil with a light hydrocarbon solvent at an elevated subcritical pressure and temperature, 2) separating a mixed solvent-deasphalted oil (DAO) phase from an asphaltene phase, 3) heating the asphaltene phase from step (2) and steam stripping the heated phase to form an asphaltene product stream, 4) heating the solvent-DAO phase from step (2) to above the equilibrium temperature of the solvent to effect separation of the solvent-DAO phase into a solvent phase and a DAO phase, 5) recovering the DAO phase and 6) heating the DAO phase from step (5) and steam stripping the heated DAO phase to form a DAO product stream, the improvement which comprises the steps of:(a) burning fuel and air in a combustion zone to mix with recirculated flue gas and form a hot flue gas;(b) supplying the hot flue gas from step (a) to a convection heating zone;(c) passing the asphaltene phase of step (2) tubeside through the convection heating zone to heat, in step (3), the asphaltene phase to provide the heated phase for steaming stripping to form the asphaltene product stream and cool the flue gas,(d) passing the solvent-DAO phase of step (2) tubeside through the convection heating zone to heat, in step (4), the solvent-DAO phase to above the equilibrium temperature of the solvent to effect separation of the solvent-DAO phase into the solvent phase and the DAO phase and cool the flue gas;(e) passing the DAO phase of step (5) tubeside through the convection heating section to heat, in step (6), the DAO phase to provide the heated phase for steam stripping to form the DAO product stream and cool the flue gas;(f) collecting the cooled flue gas from steps (c), (d) and (e) and recirculating a portion thereof to the combustion zone in step (a).