Industrial heat exchanger fouling is generally defined as the accumulation and formation of undesired materials on the exchange surface. Experimental measurements of degree of fouling are both difficult and time consuming and often do not provide accurate results. However, the modeling of the thermal resistance of fouling can inform us on the evolution of this phenomenon. The present work aimed at studying fouling three types of heat exchangers, namely stainless-steel tubular and two graphite blocks from different suppliers(A and B), in an industrial phosphoric acid concentration unit belonging to the phosphoric acid production plant of the Tunisian Chemical Group (GCT) using the measurements of the operating parameters over a period of two years. The overall heat transfer coefficients and fouling resistances were evaluated at different times using the experimental data. Our results show that the resistance of fouling reach a maximal value ranging between 1.38*10⁻⁴ and 2.55*10⁻⁴ m². K.W⁻¹ according to the type of the heat exchanger. Therefore, the experimental data of fouling resistances were compared with Kern and Seaton predictive model. Quantitative and qualitative agreement between measured and predicted fouling resistances is good with the coefficient of determination (R²) varying between 0.97 and 0.98.

工业换热器结垢通常定义为交换表面上不希望的物质的积累和形成。结垢程度的实验测量既困难又费时，并且常常不能提供准确的结果。但是，污垢热阻的建模可以告诉我们这种现象的演变。本工作旨在研究属于突尼斯化学集团磷酸生产工厂的工业磷酸浓缩装置中三种热交换器的结垢情况，即不锈钢管和两个来自不同供应商（A和B）的石墨块的结垢。 （GCT）使用两年内的运行参数测量值。使用实验数据在不同的时间评估了总的传热系数和耐污染性。我们的结果表明，结垢阻力达到最大值1.38 * 10^-4和2.55 * 10 ^-4  m ²。KW ^-1根据热交换器的类型。因此，将耐污垢性的实验数据与Kern和Seaton预测模型进行了比较。测得的和预计的防污性之间的定量和定性一致性很好，测定系数（R ²）在0.97至0.98之间变化。