Hydrocarbon conversion

A pyrolysis process of saturated hydrocarbons to produce olefins, comprising:

• (a) providing first and second mixtures, the first mixture being in the vapor phase and the second mixture comprising ≧10.0 wt. % of saturated hydrocarbon molecules based on the weight of the second mixture;
• (b) compressing the first mixture to produce a compressed first mixture;
• (c) dividing the compressed first mixture into at least first and second portions of the compressed mixture, wherein the first portion comprising ≧50 wt. of the compressed first mixture and the second portion comprising <50.0 wt. of the compressed first mixture;
• (d) dividing the second mixture comprising ≧10.0 wt. % of saturated hydrocarbon molecules into a first portion of the second mixture and a second portion of the second mixture;
• (e) transferring heat to the first portion of the compressed mixture in the first heating zone to produce a first heated portion of the compressed mixture;
• (f) pyrolyzing the first portion of the second mixture in the first pyrolysis reaction zone to convert the saturated hydrocarbons to olefins, wherein the pyrolysis of the first portion of the second mixture includes (i) an indirect transfer of heat between the first portion of the second mixture and the first heated portion of the compressed mixture and to yield a first heat-transferred portion of the compressed mixture and (ii) a conversion of ≧5.0 wt. % of the first portion of the second mixture's saturated hydrocarbon molecules, based on the weight of saturated hydrocarbon molecules in the first portion of the second mixture;
• to produce a first pyrolysis product containing olefins;
• (g) expanding the first heat-transferred portion of the compressed mixture to produce power, wherein at least a portion of the power being utilized for the compressing;
• (h) transferring heat to the second portion of the compressed mixture in the second heating zone to produce a second heated portion of the compressed mixture;
• (i) combining ≧10.0 wt. % of the expanded first heat-transferred portion of the compressed mixture, with ≧10.0 wt. % of the second heated portion of the compressed mixture to produce a combined effluent;
• and
• (j) pyrolyzing the second portion of the second mixture in the second pyrolysis reaction zone to convert the saturated hydrocarbons to olefins, wherein the pyrolysis of the second portion of the second mixture includes (i) an indirect transfer of heat between the second portion of the second mixture and the combined effluent, and wherein the first pyrolysis and the second pyrolysis reaction are operated under substantially the same conditions to produce a second pyrolysis product containing olefins.