A simulation study of a C4 oxosynthesis plant (gas recycle technology) was performed by using the software package Hysys. The process thermodynamics was described by UNIQUAC property model. An important drawback of this technology is a significant loss of propylene by the purge gas stream. Computer simulations were Carried out to evaluate the technical performance and the investment cost of a proposed revamping scheme, allowing an advanced propylene recovery from purge gases. The cost evaluations performed with Aspen Economic Evaluation are indicating that the revamping investment cost is equivalent to the propylene savings during a three years plant running period.