The results of intensification of pyrolysis reactors in Chemopetrol Litvinov are evaluated. The reasons for intensification are analyzed on the basis of current production of ethylene in Western and Central Europe. Basic technological description of equipment and the performed modifications are given. Special attention is paid to comparison of original pyrolysis reactors SRT III and new reactors GK 6. A comparison of basic construction parameters is supplemented by the results of simulation calculations performed for both reactors using a mathematical model. Finally, complex evaluation of the intensification results is given.