Research On Ionic Surfactant For Reducing Total Acid Number Of Crude Oil

With the exploration of crude oil, the crude oil with high TAN was paid more attention. In order to improve the economic efficiency and prevent corrosion of equipment in refineries, the removing acid of crude oil in packing process was studied in the paper. The ionic surfactant for removing acid of crude oil was synthesized. Carbonization was applied to regenerate naphthenic acid. In the packing mixing process, liquid-liquid mass transfer and reaction was strengthened due to the flow of liquid on the surface of packing. When the dosages of nonionic demulsifier YA, cationic demulsifier LZB and complex surfactant (LZB and YA) were 50 mg/L, with NaOH the removing acid of crude oil in the packing mixing process was better than stir mixing process.BXR and BZ was synthesized with formaldehyde, urea, epichlorohydrin and TEPA by different routes and the products were characterized by IR. BZ series was better than BXR series. Because BZ had high molecular weight and multi-branched molecular structure and a lot of amino groups, it was best for the replacemet of emulsion molecular on the oil-water interfaces. The negative surface charged in oil could be neutralized by cationic groups in BZ molecular which benefit removing acid of crude oil. When the molar ratio of TEPA with epichlorohydrin was 0.8:1, BZ-4 was the best in BZ series. When increased the molar ratio, the dehydration effect reduced due to the recation of cross-linking between the molecule and shortened effective chain length.When the lye to oil ratio of 1:4 and 1:6, the dosage of BZ-4 was 50 mg/L, the residence time was 30s, thermal precipitation time was 50 min at 95℃, the dehydration rate was 100%. Electric field process for removing acid of crude oil was optimized. When the lye to oil ratio of 1:4, thermal precipitation time was 10 min at 95℃, and the dehydration rate achieved 100% in 5 min under electric field of 600 V/cm. When the lye to oil ratio of 1:6, thermal precipitation time was 10 min at 95℃, and the dehydration rate achieved 100% in 10 min under electric field of 800 V/cm. When the dosage of BZ-4 was 40 mg/L, the lye to oil ratio of 1:2, thermal precipitation time was 5 min at 95℃, the dehydration rate achieved 100%. The TAN of crude oil dreased from 3.36 mgKOH/g to 0.14 mgKOH/g.CO2 was used to the regeneration of lye and the recovery of naphthenic acid. The regeneration time, the regeneration temperature and volume flow of CO2 which impacted the recovery of naphthenic acid was studied. With the increase of regeneration time and volume flow of CO2, naphthenic acid recovery continued to rise, While the naphthenic acid recovery decreased with the increasing regeneration temperature. When the volume of lye was 40 mL, regeneration time was 10 min at 40℃and volume flow of CO20.25 mL/min, the recovery of naphthenic acid was 98.9%.