Synthesis And Atomization Gas Dra Drag Reduction Performance Testing Device

As a result of the change of world energy structure, and the natural gas will play an increasingly important role in the international energy structure. At present, the main gas transportation mode is pipeline transportation,.With the growing demand for the nature gas that is seemed as clean energy and fuel and a large number of remote gas field exploited, gas transmission pipeline has been developing rapidly, and the technology of gas transmission has been greatly improved,so the long-distance, big-diameter and high-pressure pipeline is the main developing flow of gas pipeline in the world.And the loss of gas pipeline pressure is a problem that must be considered during the actual gas pipelining process. The pressure loss caused by the energy loss that is caused by the turbulent flow increases faster, especially in the area of high Reynolds number. As the vortex and some other sports without rules exist, there would be greater pressure loss.And the the wall roughness is the main reason causing vortex. So, in order to increase the gas throughput,it becomes the main method to decrease the pressure loss by reducing the pipe wall roughness. At present, the drag-reducing technology of using the inner-coated pipeline is adopted to reduce the pipe wall roughness, which obtains excellent results and better economical benefits. But, for this technology, the construction equipments are complex and the cost is high, the more serious problems are that the drag-reducing effect reduces and the inverse effect happens because of the runaway coating after long-time transportation. Meanwhile, non- coating pipeline is unable to be executed as a result of construction expense and other questions.The gas DRAs technology can overcome the disadvantages of the inner coating technology and has wide application foreground. In 1990s, the gas DRAs (drag reducing agents) technology was firstly introduced and was applied in field tests by America, the initial effect was obtained. The chemicals with surface activity said as gas DRAs were periodically injected into gas pipeline, the polar terminal was adsorbed onto the pipe iron wall surface to form the elastic film, so the pipe wall roughness was accordingly reduced and the drag-reducing effect was obtained.This paper overviewed the technology state and the trend of gas pipeline development, analyzed mainly the inner coating, DRAs technologies in gas pipeline and the injection technology of pipeline, introduced the significance of the study of the natural gas DRAs and the possible problems. As far as the DRAs technology, the drag reducing mechanism was generalized, the main chemicals composing DRAs were pointed out to be the chemicals or polymers having the similar structure with surface active agents, that had the polar and non-polar group. The end of polar group adhered to the pipe inner wall,and the non-polar group between the gas flow and the wall formatted a gas-solid interface. The DRAs were best to be gas or liquid that could be atomized, had enough small molecular diameter and could enter or fill in the "valley" of the wall. The pipeline injection technology of inhibitor and antifreezing agent had an important guiding significance of the study including the injection technology of DRAs, establishing and perfecting the test system measuring the drag-reducing property of DRAs, and the practical application of DRA.Five gas DRAs were designed and synthesized according to the drag-reducing mechanism of gas DRAs, that were heterocyclic oligomer I , heterocyclic oligomer II, heterocyclic oligomerIII, oligomerIV and oligomer V.The synthetic products were characterized by using infra-red spectrogram and the reacting mechanisms were analyzed by the infra-red spectrogram tracking method. The influences of several reacting conditions on the synthesis of oligomer were discussed through optimized experiment, and we got the best reacting conditions. The adsorbed films of five chemicals were prepared by selecting proper solvents, and the situations of the surface film were also discussed by the SEM (scanning electronic microscope) technology. The results showed that five oligomers obviously reduced the roughness of the original steel sheets and had latent drag-reducing property. And the oligomers were more easily atomized than the earlier productions synthesized by our group.The droplets of the DRAs that were fully atomized had small diameter but ware very uniform. They ware easily carried by natural gas, coated on the pipe wall by the turbulent diffusion, and formed homogeneous drag reduction films. So on the basis of the original test system measuring the drag-reducing property of DRAs, the atomization and spray device and the test system measuring the drag-reducing property of DRAs fully atomized ware preliminary designed. The operation flow became that: the original DRAs film forming test device was used to clean the inner pipe surface, then the pipeline was installed to the DRAs property test loop and the film on the inner pipe surface was formed by the atomization and spray device, at the end the property of DRAs was tested by the test system. The whole design detailedly gave the design targets, the design concepts, the selecting methods of parameters and the operating conditions, etc, which built the basic for the evaluation and field application of DRAs.