FLOW CAPACITY OF MAIN OIL PIPELINES WITH PREDEFINED OIL PUMPING STATIONS LOCATION WITH PERIODICAL PARTIAL OIL DUMPING

Abstract

Transportation of oil via main pipelines often requires the need for a permanent or periodic dumping of some part of the flow for further shipment of crude oil to oil refineries or filling stations. The application of such technology leads to a change in the operating mode of oil pumping stations and the oil transportation system in general. In case of emergency, an analogue of dumping is an oil leak from the pipeline in a case of violation of its integrity. Resetting a part of the flow is accompanied by a change in a liquid flow ahead of and behind the discharge point, which inevitably leads to a redistribution of pressures at the inlet and outlet of transitional petroleum pumping stations. Increasing of pressure at the output of the stations may lead to the violation of the pipeline strength; reducing of input shoring may cause cavitation operating modes of the equipment. Therefore, the study of the impact of discharges on the parameters of the operation of oil transportation systems in order to ensure their reliable, safe and economically efficient functioning is a relevant point of this area. For this purpose, based on the proposed calculated algorithms implemented in the software, the authors conducted the research on the impact of periodic oil discharges on the redistribution of hydraulic flows, energy losses at the bends, pressure at the inlet and outlet of oil pumping stations, as well as the volume of trunk oil pipelines capacity. The approbation of the proposed elaboration is carried out by defining the operational parameters of processing in functioning of oil and transport system «Druzhba» at the Mozyr-Tukholsky pass, which runs throughout the territory of Ukraine. Based on the analysis of the obtained results it was established that, depending on the volume of a discharge, the location of the limiting area, which limits the entry capacity of the trunk pipeline in general, might be changed. At the same time, the bend, ahead of which the part of oil is discharged, is not always limiting. Increasing the volume of a discharge leads to growing capacity of the pipeline at the area ahead of the point of discharge in the case when the limiting pipeline bend is behind the discharge point. If such a bend is located on the pipeline ahead of the discharge point, the increasing discharge does not affect the capacity of the initial area of the pipeline.