Synthesis Of Alkanolamide Used For Oil Recovering And Study On Compatibility With Daqing Crude Oil

A series of alkanolamides used for oil recovering which were synthesized by two-step synthetic method with the materials of fatty acid, fatty acid methyl ester and diethanolamine. The optimum conditions for the interfacial tension of the products were confirmed. According to the interfacial tension, the effect of reaction temperature, material ratio, reaction time and catalyst on reaction which was discussed, the optimum synthetic conditions was determinated.The binary system containing the alkanolamide/HPAM and the three compound combination system containing alkanolamide/HPAM/alkali which was prepared, the interfacial tension between Daqing crude oil and system was researched, the compatibleness between alkanolamide surfactant of different carbon numbers and oily sewage was investigated. The results showed that hexadecanoic acid diethanolamide and Daqing crude oil has favorable compatibleness, the binary system containing hexadecanoic acid diethanolamide(with the mass concentration of 0.2%) and HPAM(with the concentration of 1000mg/L)can produce ultralow interficial tensions (8.94×10^-3mN/m) against Daqing crude oil; the three compound combination system containing hexadecanoic acid diethanolamide(with the mass concentration of 0.2%) and HPAM(with the concentration of 1000mg/L)and Na₂CO₃(0.1%)can produce ultralow interficial tensions (6.34×10^-4mN/m) against Daqing crude oil. The optimum synthetic conditions of hexadecanoic acid diethanolamide used two-step method are as follows:(1)reaction temperature was 140℃, reaction time was 4.5hours and molar ratio of hexadecanoic acid to diethanolamide was 1:1.15.(2)reaction temperature was 80℃, molar ratio of hexadecanoic acid to diethanolamide was 1:1.55 and mass concentration of the catalyst was 0.8%, reaction time was 3 hours.In the two-step synthesis technology, the reaction temperature of the first step increased gradually with the growth of the carbon chain, and the reaction temperature of fatty acid methyl ester was about 20℃lower than fatty acid,the reaction temperature of the second step is near.The binary system which was prepared by alkanolamide(with the mass concentration of 0.2%) and HPAM(with the mass concentration of 1000mg/L)with sewage of daqing, the interfacial tension between crude oil and binary system keep invariability in 100 days, which account for the wonderful stability of system.In binary oil-displacing system, the concentration of alkanolamide surfactant is between 0.1%～0.3%, the interfacial tension became lower as the increasement of the alkanolamide concentration, but interfacial tension rise when the mass concentration of alkanolamide reach to 0.3%. The concentration of the polymer that can increase the viscosity of the system had nothing with the interfacial tension. But when Na₂CO₃ with mass concentration of 1% was added in the binary system, the interfacial tension rised as the increasement of place time.