Petroleum products interface volume reduction in back-to-back batching

Abstract

The paper deals with interface mixing in back-to-back batching light petroleum products along the same pipeline. It is known that when one petroleum product is pumped back-to-back in the line without any separating device, a mixture is formed in the interface area of consistently moving batches, which is generally a substandard product. Therefore, the issue of reducing the substandard product volume is an important task that attracts an attention of scientists for many years. Since it is known that the volume of the resulting mixture depends on the intensity of convection and turbulent diffusion processes in the fluid flow in the line, the hydraulic drag reduction, at least in the contact area of petroleum products, can reduce the interface volume. It is shown that drag-reducing agents, usually injected into the flow of the transported liquid, can also be successfully used to reduce the volume of the substandard mixture. Formulas are given for calculating the hydraulic drag coefficient of a liquid with a drag-reducing agent depending on the concentration of this additive, the Reynolds number and the relative equivalent roughness of the inner pipe wall. The main aspects of the drag-reducing agent injection to reduce the petroleum products interface mixing in back-to-back batching are presented.