This report presents a cost analysis of Styrene production from ethane and benzene. The process examined is based on concepts proposed in patents issued to Dow and Snamprogetti. In this process, ethylbenzene (EB) is first generated from benzene feedstock and recycled ethylene. Then, fresh ethane and the EB are fed to a dehydrogenation reactor to simultaneously form ethylene, which is recycled, and Styrene as final product. Pure hydrogen is also generated as by-product. This report was developed based essentially on the following reference(s): Keywords: Styrene Monomer, SM, Ethylbenzene, Ethylene, Benzene, Alkylation, Dow, Snamprogetti