The formation and deposition of coke in industrial pyrolysis quenching operation J s a serious problem. One of the most important requirements for the plant operators of ethylene production is to have a prediction for the exchanger parameters such as outlet temperature and pressure and also the coke thickness inside the exchanger tubes. In the first, called chemical deposition, the coke formed by chemical reactions at higher temperature region is deposited at the first half of the tubes. In the second half of the tube, however due to the ] lower temperature (T<500 ? C) the coke deposition increases due to the physical condensation of heavy poly-cyclic hydrocarbons condensed at this temperature region. This paper presents some of the results of a rigorous computer simulation of a naphtha pyrolysis quench cooler or Transfer Line Exchanger (TLX). The model incorporates existing molecular kinetic data for predicting coke formation rates in addition to the physical condensation of heavy aromatic hydrocarbons, and a semi empirical coke deposition model for the thermal and hydrodynamic behavior of the TLX. Finally, the model is used to simulate
the operating performance of an industrial TLX in Arak Petrochemical Complex and the results indicate a good match with fullscale plant operating data.
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