In this study, based on some important criteria, qualitative and quantitative evaluations were presented for the selection of compressors used in compressed air systems, in a petrochemical industry. Four different scenarios were investigated according to the main criteria considered for the selection of the compressors such as reliability, energy efficiency, investment, and maintenance costs. The types of compressor and their capacities were analyzed and compared. In Scenario I, the currently active electrically driven compressors were considered as backup compressors, instead of them, a new unit turbo compressor and two units of VSD screw compressors were purchased as active compressors. In this scenario, the initial investment cost is low and standby steam consumption is reduced due to the fact that the backup compressors are electrically driven. In Scenario II all active and backup compressors are replaced by a new one, which is proposed to be electrically driven. In this scenario, the initial investment cost is high, but energy consumption is very low. In Scenario III, all active compressors are planned to be replaced by new backup steam-driven compressors. In this scenario, although the initial investment costs and energy consumption are high, the reliability of this scenario is higher than the reliability of Scenarios I and II. In Scenario IV, all compressors are projected to be replaced by new and equivalent compressors. In this scenario, the initial investment cost and energy consumption are high, but the reliability of this scenario is the highest comparing all other scenarios. The aim of this study is to contribute the studies on the selection of compressors by considering some important parameters as their types and capacities, in particular, for industrial enterprises that have risk of explosion like in the petrochemical industry.