EFFECTS OF FOULING AND OPERATIONAL CONDITIONS IN PRE-HEAT TRAIN HEAT EXCHANGERS DESIGN

Heat exchanger traditional design approaches include the use of fixed fouling factors in the overall heat transfer coefficient. These values do not take into account operational conditional influences, which are very important to the fouling process. This work uses a methodology that incorporates dynamic effects of fouling in the design of pre-heat train heat exchanges, using the HTRI® software to obtain a better heat exchanger design for a specified fouling factor. The software solves a differential algebraic equation system, which describes equipment dynamics in a specified operational period, and evaluates the fouling resistance according to a fouling rate model. The fouling dynamic is described by the Ebert-Panchal Modified model, which is used for crude oil streams in pre-heat trains. The application of the methodology is shown in typical pre-heat train heat conditions, in exchangers without loop control. The examples highlight the temperature effects in fouling formation and, then, in the heat exchanger design.