Abstract
A considerable amount of oil contamination is caused by the presence of the trailing oil. This paper aims to simulate and analyze the influences of trailing oil on the quality of oil products in undulating sections. By studying the formation mechanism of mixed oil at inclining pipeline sections and the influences of velocity and oil batches on incline sections, as well as both ups and downs, the correlation is obtained between replacement time of different batches and velocity at various sections. By applying FLUENT 14.5, the maximum time of volume fraction of contaminant oil from 1% to 99% is simulated at cross-sections among different pipeline sections. Aiming at the relationship between oil product replacement time and change time of mixing section volume fraction and flow velocity, the mixing increment of undulating section relative to straight section is obtained. Combining with the empirical mixing length calculation equation, the equation for calculating mixing length considering terrain undulation is obtained. Combined with the actual operation data of Lan-Chengyu’s product oil pipeline, the error of the new mixed oil length calculation equation and actual oil mixing is 0.7966%. Excessive cutting amount of mixed oil will result in the waste of refined oil, and the less cutting amount will cause pollution of refined oil. The new mixed oil length calculation equation can more accurately guide the oil mixing cutting work at the oil station.
Highlights
According to the difference of oil qualities between two batches in product oil pipelines, the contaminant oil is formed, of which the latter one is referred to as trailing oil
In undulated pipelines, heavy oil might be deposited at a low point, where the trailing oil is in existence, and the replacement of heavy oil by light oil would aggravate the formation of contaminant oil
In all, when diesel drains gasoline in batch transportation, no matter of concave pipeline or convex pipeline, the drainage becomes faster with the increase of velocity
Summary
According to the difference of oil qualities between two batches in product oil pipelines, the contaminant oil is formed, of which the latter one is referred to as trailing oil. Mass transfer of the sub-laminar layer could be restricted by oil viscosity of different batches, causing the velocity gradients variation, which would, in turn, faster the formation of contaminant oil. Due to the difference of density, when the lighter oil of low density replaces the heavier one, the oil may remain on the surface of a heavier oil. In undulated pipelines, heavy oil might be deposited at a low point, where the trailing oil is in existence, and the replacement of heavy oil by light oil would aggravate the formation of contaminant oil.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call