Three-dimensional asymmetric flow and temperature fields in cracking furnaces

Three-dimensional flue gas flow fields and temperature profiles are calcula ted in a 4/2/1 split coil naphtha-cracking furnace with long flame burners and an asymmetric flue gas outlet. The heat streams in the furnace connecte d to the asymmetric flue gas flow fields are found to be compensated for by a net radiative heat transfer in the opposite direction. As a result, the temperature distribution in the furnace remains nearly symmetrical. A furna ce simulation under conditions of nonuniform heating confirms the compensat ing nature of radiative heat streams in the furnace. Furthermore, nonunifor m heating was found to improve the thermal efficiency of the furnace and th e cracking results. Optimization of heating conditions remains a point of i nterest.