Development And Application Of Composite Natural Gas Drag Reduction Agents

With the construction of big-sized and long-distanced natural gas transportationpipes, using natural gas drag reduction reagent will be a way to reduce transportationcost, which makes it become a hot research topic. Meanwhile anti-corrossion of pipesis also the focus of gas transportation. Therefore, a mixed drag reduction reagentwhich owns two properties above is of great practical and commercial value. In thispaper, the synthetic routes of Gemini (OPDO、CBDO) and Bola (OD、ODD、PEG400Phosphornate Ester Ammonium Salt and PEG600Phosphornate Ester AmmoniumSalt) have been proposed and improved based on the summary of existed dragreduction reagents. The best synthetic conditions for OPDO are the molar ratio of1,2-Benzenedicarboxylic acid: Diethylenetriamine: oleic acid is1:2:1.75and theamidation proceeded under190℃for2h followed by190℃for1h. The best syntheticconditions for CBDO are the molar ratio of maleic acid: Diethylenetriamine: oleicacid is1:2:1.75and the amidation proceeded under190℃for2h followed by190℃for2h. The synthetic route of PEG400phosphornate ester ammonium salts are themolar ratio of PEG400: P2O5is1:1, P2O5: H2O is1:0.5and the esterificationproceeded at90℃for5h. The synthetic route of PEG600phosphornate esterammonium salt are the molar ratio of PEG400: P2O5is1:1, P2O5: H2O is1:2and theesterification proceeded at90℃for5h. The best synthetic conditions for OD are themolar ratio of decanedioic acid: Diethylenetriamine is1:2.3and the reactionproceeded under230℃for5h. The best synthetic conditions for ODD are the molarratio of decanedioic acid: Diethylenetriamine: diethanol amine is1:1.15:1.15and thereaction proceeded under230℃for5h.Weight loss measurements and electric polarization curves show that for both Gemini and Bola, the corrosion inhibition rate increases as the addition of dragreduction increases and become steady after reaching a level. And also it decreases asthe concentration of HCl arises or temperature goes down. Both of them are mixedinhibited reagent in HCl environment and the mechanism are showed as “Geometriccovering effect”. The adsorption on the surface of steel is corresponding to Langmuirabsorption isothermal equation, which is a exothermal process with the increment ofentropy and.SEM shows that both of them can reduce the degree of coarse of the surface andOPDO has a good effect on filling.XPS shows that OPDO can form a thick membrane on the surface of steelchanging the rigid surface into elastic liquid surface, which changes the properties ofinterface. The electron binding energy of the surface of the steel sheet after thecoating film Fe were increased by0.93eV and0.68eV.Indoor circulation pipe evaluation shows that both of them has the optimalconcentration and addition amount and with the increment of flow, the drag efficiencyincreases. Under the atomization dynamic addition, the efficiency can reach18.8%and stay at18%. CBDO can reach9.8%. The best rate for OD and ODD are8%and5.08%respectively by using statically soak film-forming metod.Molecular sieve experiments show that the DRA molecules can adsorpt in5Amolecular sieve, but the DRA molecular desorption at high temperatures, so the DRAhas no side effects on the reuse of5A molecular sieve.