The problem of modeling pyrolysis of naphtha in a modern SR T-VI large-capacity furnace from ABB Lummus Global (USA) was examined. Curves of the yield of basic products as a function of the composition of the feedstock and pyrolysis regime were obtained with the experimental data and physicochemical characteristics of the process. The model is intended for predicting the composition of pyrolysis gas and controlling the pyrolytic process in an active plant.In many domestic ethylene units, obsolete naphtha pyrolysis furnaces are being replaced by modern type SRT-VI furnaces (SRT = Short Residence Time) of high individual capacity: output in feedstock of the order of 300,000 tons/year. The SRT-VI furnace (Fig. 1) differs from the preceding modifications due to the elevated thermal factor (q av » 100 kW/m 2 ) of the radiant part of the coil, high degree of branching of the pyrolysis coal, and shorter feedstock residence time (~0.22 sec) in the reaction zone.With respect to its design, this furnace is much more complicated than the preceding furnaces and can operate in a wide range of variation of the process parameters and feedstock composition. Optimization of the operating conditions in the current market economy is presenting some difficulties for plant personnel. According to ABB Lummus Global data [1], the optimum pyrolysis conditions in the EP-450 ethylene unit will allow increasing profits by 6%.

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