The cost of the compressors was calculated based on the compressor duty given in UniSIM. When modeling the plant in UniSIM no pressure drop was assumed. To be able to calculate the compressor duty, a small expansion valve was inserted before the compressor to compensate for the pressure drop. The pressure drops were based on experience from the industry (O2). A total of two compressors were used in the model. The first compressor (COMP-1) was used to compress the synthesis gas from the reformer section. The pressure drop of the reformer section was assumed to be 4 bar (from 30 to 26 bar). Thus the compressor had to compress the gas from 26 to 50 bar. The second compressor (COMP-2) was used to compress the recycle over the methanol reactor, which had an assumed pressure drop of 2 bar. Both compressors were assumed to be regular centrifugal compressors.