| Because the hydrocarbon resourses in the earth are pockety and the demand is different among areas, we need a storage and transportation system to connect the users and the place where hydrocarbon is extracted. Once the storage and transportation system was interrupted, there would be a great influence on the economic development of consumption areas and production areas. As for as the pivotal link—transportation, the newly-built pipeline could't meet demand, and the old pipeline's conveying capacity decreased gradually because of aging. The drag-reducing technology was the most effective solution to settle this difficult problem. At present, the drag-reducing technology of using the inner-coated pipeline is adopted to reduce the pipe wall roughness, which had obtained excellent results and better economical benefits. But, for this technology, the construction equipments were complex and the cost was high, furthermore we just got profit only when used in big caliber(>500mm), the more serious problems were that the drag-reducing effect reduced and the inverse effect happened because of long time transportation and irregular pigging.In 1990s, the gas DRAs(drag reducing agents) technology was firstly introduced and applied in actual pipeline by America, and the initial effect was obtained. The chemicals with surface activity said as gas DRAs were periodically injected into gas pipeline, the polar groups were adsorbed onto the pipe iron inner surface and formed an elastic film, so the roughness of the pipe wall was accordingly reduced and the drag-reducing effect was obtained. The gas DRAs technology could overcome the disadvantages of the inner coating technology and had wide application foreground. At present, this technology is in researching stage abroad, and the domestic research is blank.This paper summarized the current situation & development trend of gas pipeline, and analyzed mainly the inner coating and DRAs technologies in gas pipeline. As far as the DRAs technology, we did some exploratory research on the drag reducing mechanism and pointed out that the main chemicals composing DRAs were big molecule chemicals or polymers having the similar structure with surface active agents: one group was long chain fatty group and the other group was nitrogenous group bonding stably with iron surface. The feasibility of gas DRAs and the possible problems were also analyzed.Three gas DRAs were designed and synthesized according to the drag-reducing mechanism of gas DRAs, :multi-amido DRA, long-chain alkylolamide I and long-chain alkylolamide II . The synthetic products were characterized by infra-red spectrogram. The influences factor on the synthesis were discussed through optimized experiments and the best reacting conditions were given. We observed the film formed by these three chemicals on the steel sheet surface by SEM (scanning electronic microscope) technology. The results showed that they all had good film-forming property and had the potential to be gas DRAs.Some changes were done to the drag-reducing test loop, directing towards the problems which appeared in the test process; a data acquisition system was exploited and the evaluation procedure of the drag-reducing property was established basically; we tested the drag-reducing property of these three chemicals at different temperature and different concentration, analyzed the experimental data and gave the suggestion to eliminate the systematic error. |
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