An electric power distribution switchboard in which one or more functional units are equipped with a switching device compartment that integrates primary and secondary functions. Said shoe has a sole for receiving one or more studs by means of a moulded body which is arranged on the sole at an angle of between 15 and 25, preferably 18, to the plane of the sole and which has an opening for receiving a securing device which is located on the stud. The present process is particularly effective and beneficial in removing contaminants such as CO2 andor H2S from a natural gas at high adsorption pressures to create product streams of very high purity.