Development And Evaluation Of Drag Reduction Agents For Natural Gas Pipeline

Naturanl gas, as a clean energy, is playing an increasing important role in the international energy market. Along with the increasing demand for natural gas, the transportation technology needs to be greatly enhanced. Besides building more pipelines and pipe networks, decreaseing the flow resistance in the existing pipelines is also an effective way to increase the transportation ability. As one of the fricton reduction technologies, Drag Reduction Agent(DRA) is widely studied around the world in recent years.Based on the friction reduction mechanism, ammonium salt of phosphornate ester (PEA), as a kind of DRA, is synthesized in this paper. The synthesis conditions of OPEM and oleic acid imidazoline are optimized respectively in this paper. The highest productivity of OPEM is got when the reaction time of esterification is 6h, temperature of the esterification is 70℃, the molar ration of OPEM and P2O5 is 3.5:1, the molar ration of H2O and P2O5 is 1:1, temperature of the hydrolysis reaction is 90℃. The optimal synthesis condition for oleic acid imidazoline is that the molar ration of Oleic Acid and Stoichiometric Diethylene Triamine (DETA) is 1.3:1, temperature of normal pressure process is 210℃, reaction time of normal pressure process is 4h, temperature, reaction time and vacuum degree of vacuum process is 230℃, 6h and 9.8-1.0×10~4Pa respectively.SEM and electrochemical analysis system are used in this paper respectively to evaluate the DRA's film forming property and film morphology. The test result shows that except the Octadecanol Double Phosphate Ester Monoethanolammonium the other PEAs all shows excellent film forming property.A model circular loop is used in this paper to evaluate the DRA's drag reducing efficiency respectively. The result shows that acetophenone-formaldehyde-dibutylamine mannich base and oleic acid imidazoline has no drag reducing efficiency when used singly and get a 6.7% drag reducing efficiency when used together, the drag reducing efficiency of OPEM is 8.0%, and the PPEM's is 12.38% and 6% respectively due to the different adding method.The pilot production of PPEM is carried out successfully. The key points of the production are summarized and the experience for expanded production is enriched. PPEM's drag reducing efficiency is also tested in Dagang oilfield. The result shows that it has an excellent drag reducing efficiency in the practical natural gas pipelines, the highest one is 17.8%.The drag reduction mechanism of DRA is further discussed in this paper. The author thinks that the compound which can form a film with certain thickness is more properly developed as a kind of DRA.