Impact of crude oil fouling composition on the thermohydraulic performance of refinery heat exchangers

Abstract

Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.Crude oil fouling studies generally focus on the thermal impact of organic deposits. The hydraulic limit given by pressure drop is, however, frequent cause of shutdowns and cleaning. Inorganic matter is often found in deposit analysis, but ignored in most studies. A case study is presented based on published plant data from the Esfahan Refinery (Iran). A detailed thermo-hydraulic model of heat exchangers undergoing fouling, together with the available data and reasonable assumptions, is applied to study the exchanger most affected by fouling. Novel modifications are made to: i) capture the effect of inorganics on the deposit conductivity; and ii) use pressure drop measurements, instead of temperature, to fit key fouling parameters. Good agreement is obtained between model and plant data. This demonstrates the need and benefit of considering fouling layer composition and both temperature and pressure drop data in the fitting of model parameters and interpretation of plant data. The potential of using such a model for early detection of operative problems is highlighted.