Abstract: Ethylene belongs to intermediate in the pyrolyticprocesses. The yields of ethylene change with pyrolsis durations whichreach the peak at the optimal resident time. While the reactiontemperature increases, the peak yields of ethylene is increased and theoptimal resident time is sharply shortened. The vertical pipe furnacesin common use in convensional pyrolytic technology are difficult tosatisfy the demands for significantly higher yields of ethylene andlower production costs. The advantages and disadvantages of heating bystanding shock wave are reviewed and the developing heating method bymixing of opposite jets with high temperature steam flow is describedbriefly.