The pipeline flow of paste slugs: I. Concepts and general flow behavior

Cylindrical paste segments, carried by a liquid hydrocarbon (such as crude petroleum), can be transmitted through pipelines in much the same manner as rigid capsules or ingots, and the technique may therefore offer a useful method for long‐distance bulk commodity transportation. In this paper, basic concepts of paste slug conveyance are briefly discussed and a first detailed study—mainly concerned with general flow behavior and flow velocities of individual slugs in an experimental 1‐in. i.d., 70‐ft. long closed‐loop line—is reported. As a matter of convenience, attention is confined to the flow of coal paste segments (prepared from a 70:30 w/w coal‐water paste) in a refined light mineral oil (ρ = 0.829 gm./cc. and μ = 7.05 cp at 60°F.). Slug‐to‐pipe diameter ratios varied from 0.5 to 0.8, and fluid velocities ranged to 11 ft./sec. (corresponding to pipe Reynolds numbers up to ca. 12,000).