Process to obtain a compressed gas

A process to obtain a compressed gas starting from a starting gas having a lower pressure by performing the following steps:

• (i) increasing the pressure and temperature of a gas having an intermediate pressure by means of indirect heat exchange against a fluid having a higher temperature to obtain a gas high in pressure and temperature (ii) obtaining part of the gas high in temperature and pressure as the compressed gas, (iii) using another part of the gas high in temperature and pressure as a driving gas to increase the pressure of the starting gas in one or more stages to obtain the gas having an intermediate pressure for use in step (i), wherein the pressure of the starting gas is increased in step (iii) in n levelling stages, wherein n is 2 or more and wherein part of the driving gas is added to the gas obtained in the (n−1)th levelling stage to increase the pressure of said gas in the n th levelling stage to obtain the gas having an intermediate pressure and wherein part of the remaining driving gas is added to the gas obtained in the (n−2)th levelling stage in the (n−1)th levelling stage and continuing said sequence of adding part of the remaining driving gas to the gas obtained in the previous stage for the remaining (n−2) levelling stages and adding the then remaining driving gas to the starting gas in the first levelling stage.