Patent attributes
A method and apparatus for processing a hydrocarbon stream are described. The method includes heating a feed stream in a convective bank. The heated feed stream is reacted in a first reaction zone to form a first effluent, which is heated in a first radiant cell. The first radiant cell combusts fuel to heat the first effluent and forms a first exhaust gas. The first exhaust gas is contacted with the convective bank to heat the feed stream. The outlet temperature the heated feed stream from the convective bank is controlled by introducing an additional gas stream into the convective bank. There can be additional reaction zones and radiant heaters.