Method and compressor module for compressing a gas stream

A compressor module comprising a two-stage compressor part, a drive part and a power transfer between the compressor part and the drive part over lines with hydraulic fluid, characterized in that the drive part for each compressor stage contains a hydraulic fluid pump each with an adjustment mechanism for conveying the hydraulic fluid.

A process comprising compressing a gas stream of entry temperature t1 with the help of hydraulically driven piston compressors in two compression stages from an entry pressure p1 to an intermediate pressure p2 after the first compression stage and from intermediate pressure p2 to an exit pressure p3 after the second compression stage, and the gas stream compressed to intermediate pressure p2 is cooled to entry temperature t1 before entry into the second compression stage and identical pressure ratios p3/p2=p2/p1 are used in the compression stages, characterized in that the pressure ratios are adjusted accordingly by matching a hydraulic fluid stream for driving the first compression stage and a hydraulic fluid stream for driving the second stage with respect to their flow rate, with the help of two adjustable hydraulic fluid pumps with the proviso that a pressure between 250 and 350 bars is used as exit pressure p3.