Modelling and evaluation of the effects of high back pressure (HBP) on refinery Flare System network

Abstract

Safety and reliability of the flare system are often affected by High Back-Pressure (HBP). The primary aim of this study is to simulate a steady-state model of flare system using Aspen Flare System Analyzer and with the aid of real plant data generated from Kaduna Refining and Petrochemical Company (KRPC) Ltd, Nigeria. Three credible scenarios (normal operation/surplus fuel, cooling water failure and power failure) were considered. The results showed that the steady-state model of flare system for normal operation (Surplus Fuel), cooling failure and power failure scenario and the flare system meet performance requirements at a system back pressure of 1.01325 bar, except for cooling water failure scenario which showed the occurrence of high fluid velocity and momentum (rhoV 2). Also, flare operation at normal back pressure, for all three scenarios does not exceed design and operational limits. The work recommends that KRPC managers should review options for reducing HBP particularly for cooling failure and power failure scenarios such that the back pressure would not exceed 10% of set pressure for the conventional valves.