Data-Driven Assessment of Plate Heat Exchanger Fouling in a Vegetable-Oil Deodorization Unit

Abstract

Plate heat exchangers (PHEs) are widely used in process industries because of their high heat-transfer coefficients, compactness, and ease of cleaning [1]. However, deposition of organic and inorganic foulants on plate surfaces degrades thermal performance, increases energy consumption, and can drive unplanned shutdowns [2]. This study quantified fouling behavior in two gasketed plate heat exchangers installed in the deodorization section of a vegetable-oil refinery. Several months of historian data were extracted from the plant distributed control system, including temperature indicating transmitters (TITs) and flow indicating transmitters (FITs) on the oil and water circuits. The raw 30-s measurements were aggregated to 5-min averages, cleaned using physical consistency checks and outlier removal, and, where necessary, reconstructed using steady-state energy balances and pump curves to infer missing temperatures and flow rates.

For each exchanger and time step, the overall heat-transfer coefficient Ut and fouling thermal resistance Rf were computed from the measured heat transfer rate (Q) and log-mean temperature difference (LMTD), using a clean reference coefficient Uclean determined immediately after confirmed cleaning events.

Results showed that the preheater (HX-103) experienced gradual fouling with typical Rf values on the order of 10−3 , hr·ft2·°F/Btu, while the final coolers exhibited larger fouling resistances and more pronounced step reductions in Rf following maintenance. The methodology provides a practical framework for condition-based cleaning of PHEs using routinely collected plant data and can be extended to other units within the facility.