FEATURES OF IMPLEMENTATION AND OPERATION OF PRESSURE WAVES SMOOTHING SYSTEMS IN OIL PIPELINE TRANSPORTATION

Abstract

Background The scale of PJSC Transneft activities implies a high load and almost uninterrupted operation of the pipeline network. At the same time, during its operation, deviations from the standard modes of transportation, pressure pulsations and hydraulic shocks are possible, the consequences of which can damage equipment or cause damage to the pipe and oil outflow into the environment. A regular or abnormal shutdown of an aggregate or an entire intermediate oil pumping station (OPS) during pumping is accompanied by an increase in pressure, resulting in a steep pressure wave propagating upstream in the direction of the previous station. Due to friction losses, the initial perturbation decays, i.e. its slope and amplitude decrease in absolute value. Reaching the previous station, the increase in pressure wave leads to an increase in pressure at the station outlet. To maintain the setpoint at the LPS outlet, the automatic control system (ACS) of the pressure creates a wave of pressure reduction (vacuum). If the speed of the ACS is not enough to offset the surge pressure, the pressure at the outlet of the pump station can reach the setpoint for the operation of the corresponding station overpressure protection. The action of general station protection comes down to shutting down a single pump or an entire station. When this protection is triggered, a wave of pressure reduction begins to propagate towards the incoming wave of pressure increase downstream. As a result of wave interference, the pressure decreases in the linear part of the pipeline. However, before the wave reaches the previous OPS, the pressure in the section between stations may exceed the allowable working pressure of the pipe sections, which can lead to depressurization of the pipeline. In most cases, in the Transneft system, the protection of line pipes sections from verpressure in transient processes caused by the disconnection of the main pumping unit or the whole pumping station is protected by means of pressure wave smoothing systems. Aims and Objectives The study aim is study of the issues of protection of trunk pipeline facilities from high-pressure waves arising from pressure pulsations, water hammer during normal or abnormal shutdown of pumping units or an intermediate pumping station as a whole, with unauthorized closure of valves, etc. Results The main aspects of the implementation of pressure wave smoothing systems are considered and the economic criteria for their installation on existing and projected oil pipelines are defined. An example is given of the calculation of non-stationary processes necessary to substantiate the expediency of using the high pressure pump at intermediate oil pumping stations. Presents the main types of system designs, features of their operation and planned maintenance.