Study On Removing Naphthenate From VGO By Fiber Membrane

This paper mainly discussed the deacidification of Suizhong36-1 VGO with high acid number by fibre membrance. Adding superfluous alkali lye into the VGO, the petroleum acid can be changed into naphthenate. After that, the naphthenate can be separated from VGO by means of fibre membrance or intermittent extraction separation. The separation effect can be valued by the pH and water content of the oil phase and solvent phase.The static sedimentation effect can be valued by the pH and water content of the oil phase. And the ratio of removing naphthenate and recycling petroleum acid can value the effect of removing naphthenate and recycling petroleum acid.The results show that: compared with the non-diluted oil, the ratio of removing naphthenate and recycling petroleum acid in diluted oil was greatly improved with water as extraction agent by fibre membrane. But the emulsification was very serious and the ratio of recycling oil was quite low. However, in the test of separation naphthenate by fibre membrane with multiple solvents as extraction agent, the emulsification was lightened and the ratio of removing naphthenate and recycling petroleum acid was greatly improved. With the improvement of the rate of the multiple solvents, the ratio of recycling petroleum acid also can be improved. Meanwhile, compared with single-stage extraction, the acid number of oil in the couple-stage extraction can be lowered and the ratio of removing acid can be improved. The pH and water content of the oil phase can be decreased according to the static sedimentation time with water or multiple solvents to separate naphthenate by fiber membrane. A better process conditions is dilution ratio 0.3:1, the ratio of multiple solvents1:1, solvent-oil ratio 1:1,at couple-stage extraction, Under this condition, the ratio of removing naphthenate is 98.6% and the ratio of recycling petroleum acid is 81.7%.According to the test of removing enriched naphthenate with multiple solvents, a better process conditions is concentration factor 60%, the ratio of multiple solvents 1:1, solvent-oil ratio 1:1. Under this condition, the ratio of removing naphthenate and recycling petroleum acid can be both increased to 97%in the single-stage extraction, and under the same condition, the acid number can be lowered to 0.086mgKOH/g and the ratio of removing acid can be increasd to 99.12% in couple-stage extraction.