| Drag Reduction can be achieved by applying a smooth film on the inner surface of natural gas pipeline to reduce the friction between flowing gas and pipe wall dramatically. Compared to inner-coating technology, Injecting DRA has easier operation equipments and lower investments; fill when it is necessary; not only can it be used for new pipes, but also for the old ones. It can improve the delivery flexibility of pipes effectively and save the cost. At present, this technology is in developing phase at home and abroad, the specific excellent DRA has not yet been selected, and the drag reduction effect is unstable, whether the DRA adopted in high-pressure natural gas pipeline is able to bring significant effect or not needs further evaluation. Therefore, performance evaluation of DRA, which is of great significance has become an indispensable intermediate link of practical application.The indoor loop evaluating property of natural gas DRA was designed. Both of static test, which immerse the pipe to form film and dynamic test, which adopt the atomization filling to form film can be achieved. Through the hydraulic analysis, the result shows that the Reynolds number of the evaluation system is about 105, in turbulent flowing section; the shear stress is of the same order of magnitude as the one of on-site pipe wall. We can include that it can simulate commercial pipelines approximately to evaluate the film formation/drag reduction effect and shearing resistance of natural gas DRA.Using this set of device, carried out the static experiment to evaluate the drag reduction effect of AFOMB, OIM, OPEM and PPEM at different concentration and their combination solution. Besides, Atomization filling dynamic experiments of PPEM and PPDTM were also demonstrated. At present the best result is PPDTM. Drag reducing Efficiency reaches16.6% at 140Nm3/h volume flow rate and 7% concentration, and this value can be maintained at about 8 % after one week; Secondly is PPEM, the static test and dynamic test reduction rate reached 12.38% and 6% respectively; Thirdly is OPEM, Drag reducing performance is best when the 0.2g/mL ethanol solution is applied. drag reduction rate reaches the highest value of 8% at 140Nm3/h volume flow rate; The result reveals that no significantly effect is produced when The AFOMB and OIM work alone, but the drag reduction rate of combination solution of them can run up to 5.41% at 140Nm3/h volume flow rate when their mixture ratio is 6:12.A field test used 2 tons of 7% PPEM ethanol solution. The site filling experiment of DRA was carried out on the on-site natural gas pipeline. Test showed that: the average pressure drop between first and terminal station has been reduced at the same flow rate after injecting of DRA, drag reduction rate can reach 13.12 ~ 17.81%. The DRA can not only reduce the friction loss, but also have good compatibility with condensate, corrosion inhibitor and hydrate inhibitor etc. inside the tube, the purification and sub-transmission of downstream natural gas were not adversely affected by it. To sum up, it is a new type of DRA that demonstrates great potential.
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