The process of naphtha pyrolysis in the heat-carrier at ultra-short time of feedstock / heat carrier mixing is studied. The experiments are carried out within the temperature range at the reactor inlet of 1240-1400 K. Detailed data on the temperature and product composition distribution along the reactor axis are obtained. Experimental results are compared with the calculation. Significant enhance of ethylene yield in our experiments with relation to furnace pyrolysis method is found. (c) 2012 Elsevier B.V. All rights reserved.