This article proposes a new approach for dealing with maintenance issues for large industrial processes. The case study is taken from an industrial implementation of a condition-based maintenance project for the heat exchangers from the crude preheating train of a European refinery. The application was developed based reconciled data using the advanced data validation and reconciliation tool, VALI, developed by Belsim.
The article proposes the riguroous calculation and monitoring of the fouling factors of heat exchangers as crucial parameter to alert the operator about the condition of the heat exchangers. The calculation of fouling factors is performed automatically by the application with a minimum initial input effort from the part of the modeler: design date for film transfer coefficients for the both sides of the heat exchanger. Industrial data shows that the heat exchangers from the crude preheating train are prone to relatively quick fouling. The financial analysis of the impact of the fouling problem on the normalized daily fuel consumption in the crude furnace has shown that the high initial financial gain of a preheater cleaning can amount to as much as 20% of daily fuel cost. However, the performance degradation sets in very fast and the high initial gains are not sustained for prolonged periods of time. On the other hand, the overall performance degradation slows down in time and the performance of the crude preheating train stabilizes at lower values, making the decision process for heat exchanger cleaning more difficult in situations of pressures to maintain production volumes.