It has become a well-known fact that finding sustainable solutions to the unavoidable high pressure losses accompanying pipeline flows to increase the pumping capacity without necessarily adding more pump stations is inevitable. Polymers, as one of the drag reducing agents which have been found to offer such an economic relieve, is the most widely investigated and most often employed in industries because they can produce drag reduction up to 80% when they are added in minute concentrations. In addition, polymer additives modify the flow configurations of multiphase flows to such an extent that stratification of individual phases is enhanced thereby making the separation of the phases at the fluid destination much easier. The achievements so far made and the challenges facing the use of polymers as drag reducers in turbulent single and multiphase flows are comprehensively reviewed. This review discusses the experimental studies of the effects of polymer additives in turbulent flows, the analytical studies, and the proposed models as well as the suggested mechanisms that explain the drag reduction. Likewise, specific areas of interest in the review include phenomena of drag reduction by polymers, factors influencing the effectiveness of the drag reducing polymers, methods of injecting the polymers into the base fluids, degradation of the polymers and industrial applications of polymers as drag reducing agents. The current and future research interests are also addressed. Although finding reveals that there are quite a lot of research in this area, most of the experimental and theoretical works are devoted to single phase flows while the remaining ones are mostly directed towards gas–liquid flows except in very recent time when investigation into the use of polymers in liquid–liquid flows is being focused. Despite this voluminous works on drag reducing polymers, there are no universally accepted models and hence the mechanisms of drag reductions by polymers.

Roles of drag reducing polymers in single- and multi-phase flows

This state of-the-art review is published in two parts: Part 1 has already appeared and deals with basic aspects of the subject, while this part sets out details of specific drag reduction applications. These include oil pipelines, oil well fracturing, sewers, open channels, hydropower penstocks and culverts, the hydrotransport of pulverised solids, the effect of drag reducing additives on fluid machinery, marine applications, their use in heating systems, firefighting and jet cutting. The preparation and injection of polymer solutions, the economics of their use, their degradation in flow and the pollution implications of their release into water courses are aslo covered. Wherever possible field test results are included and discussed. The bibliography contains 154 references to published material.

The Effect Of Drag Reducing Additives On Fluid Flows And Their Industrial Applications Part 2: Present Applications And Future Proposals*

https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=8404&context=masters_theses

Effect of polymer on disproportionate permeability reduction to gas and water for fractured shales

Artificial intelligence approach to predict drag reduction in crude oil pipelines

Enhance flows of waxy crude oil in offshore petroleum pipeline: A review

Tests over a 28 mile segment of 8 in crude oil pipeline at normal flow velocity of 6 ft/sec gave drag reductions of 16, 21, and 25% for polymer concentrations of 300, 600, and 1000 ppm by volume When the flow velocity was decreased, the drag reduction also decreased A further test in 32 miles of 12 in pipeline gave similar results In none of the tests did the polymer appear to degrade or lose effectiveness because of turbulent shear in the lines Laboratory tests in a 1 in ID pipe viscometer for the polymer and various polyisbutylenes covered a range of concentrations and flow velocities, with results showing the same general characteristics as in the large pipelines An equation which correlates the 8 in and 12 in pipe data as a function of flow velocity and polymer concentration is presented

John D. Culter

Papers

Drag Reduction with a Polymeric Additive in Crude Oil Pipelines