A process for recovery of C 2 and C 3 components from an on-purpose propylene production system comprising: cooling a combined de-ethanizer overhead light vapor from a de-ethanizer and cracked gas vapor to a temperature at which at least 80 wt% of the vapor is condensed to form a first partial condensate and a first residual vapor; passing the first partial condensate to a bottom portion of a rectifier ; passing the first residual vapor up through packing of the rectifier while contacting the first residual vapor with a countercurrent stream which comprises from 75 to 95 wt% C 2 components, from 5 to 25 wt% C 1 components and from 0 to 5 wt% C 3 components thereby producing a rectifier overhead stream which comprises from 20 to 45 wt% C 1 components, from 40 to 60 wt% C 2 components and from 0 to 5 wt% C 3 components and a rectifier liquid bottom stream ; passing the rectifier liquid bottom stream to the de-ethanizer; partially condensing the rectifier overhead stream in one or more heat exchanger stages to cool the rectifier overhead stream to produce a second partial condensate with a second residual vapor which comprises less than 5 wt% C 2 components and a first residual liquid which comprises from 75 to 95 wt% C 2 components; passing the combined second residual vapor and first residual liquid to a knockout drum to separate the second residual vapor from the first residual liquid; optionally, using the second residual vapor as a fuel gas and/or as a cooling medium in the one or more heat exchanger stages ; passing a first portion of the first residual liquid to a top portion of the packing in the rectifier to serve as the countercurrent stream; and passing a second portion of the first residual liquid to a product recovery system. cooling a combined de-ethanizer overhead light vapor from a de-ethanizer and cracked gas vapor to a temperature at which at least 80 wt% of the vapor is condensed to form a first partial condensate and a first residual vapor; passing the first partial condensate to a bottom portion of a rectifier ; passing the first residual vapor up through packing of the rectifier while contacting the first residual vapor with a countercurrent stream which comprises from 75 to 95 wt% C 2 components, from 5 to 25 wt% C 1 components and from 0 to 5 wt% C 3 components thereby producing a rectifier overhead stream which comprises from 20 to 45 wt% C 1 components, from 40 to 60 wt% C 2 components and from 0 to 5 wt% C 3 components and a rectifier liquid bottom stream ; passing the rectifier liquid bottom stream to the de-ethanizer; partially condensing the rectifier overhead stream in one or more heat exchanger stages to cool the rectifier overhead stream to produce a second partial condensate with a second residual vapor which comprises less than 5 wt% C 2 components and a first residual liquid which comprises from 75 to 95 wt% C 2 components; passing the combined second residual vapor and first residual liquid to a knockout drum to separate the second residual vapor from the first residual liquid; optionally, using the second residual vapor as a fuel gas and/or as a cooling medium in the one or more heat exchanger stages ; passing a first portion of the first residual liquid to a top portion of the packing in the rectifier to serve as the countercurrent stream; and passing a second portion of the first residual liquid to a product recovery system. <EOS>