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Synthesis Of Organic Chromium And Study On The Performance Of Delaying Crosslink

Posted on:2016-05-07Degree:MasterType:Thesis
Country:ChinaCandidate:Y F LiFull Text:PDF
GTID:2271330461981419Subject:Chemical Engineering and Technology
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Profile control agent, comprising partially hydrolyzed polyacrylamide(HPAM)cross-linked with chromium(Ⅲ), was finding widespread use in the oil field and was achieved significant effect in terms of increasing oil production and decreasing water cut. The studies on the structure and properties of organic chromium(Ⅲ), and on the mechanism and kinetics of the crosslinking reation of organic chromium gel system were very important to the site application of the gels technology.First, using lactic acid as a ligand reacted with chromium(Ⅲ) into chromium lactate complex. Synthesized complex was characterized by IR spectroscopy, UV-visible spectroscopy, Atomic Absorption Spectroscopy and elemental analysis, and the molecular formulas was Cr(C3H5O3)3?6H2O.Then, using viscosity method and Uv-visible spectroscopy method studied on the crosslinking dynamics of HPAM/Cr(Ⅲ) systems. Dividing the gelation process into three periods, including induction period, acceleration period and stable period in the first method.In the 30 to 60℃ range, the apparent activation energy of the acceleration period was56.11KJ/mol. Meanwhile using Uv-visible spectroscopy method, the gelation process could be distributed into two periods: fast and slow gelation. The apparent activation energy of the fast gelation was 60.95KJ/mol in the 30 to 60℃ range.Finally, study on effect of delayed cross-linked properties with the type and dosage of the ligand in the organic chromium gel system. The stronger complex ability of ligand, the better stablility of complex, and the slower reaction rate of organic chromium and HPAM, thus, the gelation time was delayed into a few days or longer. Adding more ligands into the gel system,the direction of crosslinking reaction was from the opposite, and the rate of crosslinking reaction slowed down, therefore, rewarding the gelation time.Meanwhile, the mechanism of the gel system crosslinking reation was obtained. The scramble for chromium(Ⅲ) between polymer and ligand was a competitive reaction. The rate between chromium complex and polymer was depended on the rate of chromium(Ⅲ) released from organic chromium complex. The released chromium could crosslink with carboxyl of polymer, either or form into a new organic chromium complex with free state ligands, thus,the scramble for chromium(Ⅲ) between polymer carboxyl and free state ligands was a competitive reaction...
Keywords/Search Tags:organic chromium, dynamics of crosslinking reaction, mechanism of the crosslinking reation, delayed crosslink, partially hydrolyzed polyacrylamide
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