The Oil Fine Chemicals To Crude Oil Pretreatment Process

Along with the inferiority and heavilization of worldwide crude oils, more and more attentions are paid to its pretreatment. The desertation focusing on multifunctions of pretreatment for crude oils synthesizes a series of fine chemicals for petroleum, with which the contents studied the relationship between the electric desalting demulsifiers and asphaltic, paraffinic crude oil, deferrization, desulfurization, desalting mechanism for crude oil and model of salt transfer.Asphaltene in crude oil causes raising of crude viscosity and its micelles interferes with the salt transfer from oil to aqueous phase. The oil-soluble phenolic resin series are compatible with asphaltic crude oil for desalting, whereas the polyhydric alcohol series are more efficient in dewatering efficiency. After the recombination of phenolic resin demulsifier 5# with polyhydric alcohol 6# desalting dewatering efficiency (DDE) for asphaltic crude oil can reach 78% and 100%. Experimental results indicate that paraffin in crude oil exerts a great influence on DDE and dynamic viscosity of crude oil increases with the increase of paraffinic content in crude oil by testing dynamic viscosity. Because higher viscosity for paraffinic crude oil leads to inefficient dewatering, and hence decreases the desalting efficiency. Among different kinds of demulsifiers series, the polyamine series are more compatible with paraffinic crude oil for desalting and diamine series are compatible for dewatering. The triblock copolymer structure of PO-EO-PO for polyhydric alcohol is more effective with this type of crude oil than the diblock of PO-EO. DDE of Polyamine demulsifier 3# for crude oil 5# which paraffinic content is 25.9% are 89% and 87%.It is found that 48~75% iron exists in Shengli, Rocalya and Luning crude oils as organacid salt and 6~40% as iron complex. Most irons can not be efficient removed from crude oils using only demulsifier in the desalting process. Four deferric agents are synthesized and the mechanism of deferrization is discussed. The deferric agents can get a better result of deferrization for three crude oils, in which the polyanine-carboxylate types have a better deferrization rate than the organophosphate ones. Deferric agent TE-4 can effectively remove Fe, Ca, Na and Mg from crude oils as well as part of Ni and V. There exists an optimal dosage for deferric agent TE-4 and at the optimal dosage, iron content after deferrization for three crude oils is 2.5μg/g, 12.44μg/g and 2.9μg/g, corresponding to deferric rate of 74.25%, 66.85% and 94.54% respectively.Some desulfurizers are synthesized for Iran and Saudi crude oils, among which TS-2 is efficient for Iran crude oil and TS-1 for Saudi crude oil. At the optimal conditions, desulfurizing, desalting and dewatering efficiencies of TS-2 for Iran crude oil reach 26.3%, 74% and 85% and TS-1 for Saudi crude oil are 16.1%, 59% and 88% respectively.Demulsifers of SA, SB, SC and SD series containing carboxyl and nitrogen are synthesized with fatty acids as hydrophobic group and amines as hydrophilic group and synthetic mechanism is also discussed. SC-14 polymerized without PO and EO is efficient for Shengli crude oil in DDE and hence its synthesis process is simple, convenient and safe. At the optimal conditions, DDE of SC-14 for Shengli crude oil are 76.3% and 79.5%. Whereas SD-12 containing oxyethylene group is compatible with Oli crude oil and thus effectively demulsifies for such oil-water emulsion. At the optimal conditions, DDE of SD-12 for Oli crude oil also get a better result..Desalting efficiencies for SC and SD series can be improved by the salt transfer agent, that is, desalting efficiency of such agent recombinated with demulsifier for Shengli and Oli crude oils can raise from 60% to over 70%. After studied the salt transfer process further, a model of hollow spherical shell is used for W/O emulsion formed by mixing 400~450℃distillate of Shengli vacuum distillation with 20% water. The model approximately coincides with the test result after verified. Such model manifests that desalting and dewatering process has relation to temperature, crude oil and demulsifier properties, emulsive conditions, volume of oil and water phase etc. As a result, concerning rupture of interfacial membrane, it is helpful for pretreatment process of crude oil.