For lower capacities and for applications where high delivery pressure is required, like for instance on LPG carriers, the inert gas is compressed by a rotary screw type compressor. The compressor is working at the same time as a dryer by condensing most of the water in the after cooler. However, for low dew-point an absorption dryer will be required where the inert gas is dried to the final dew-point.
Combustion type nitrogen generators:
Nitrogen can be generated by the same high pressure type inert gas generator by adding a CO2 stripper. This stripper removes the CO2 in the inert gas (originally N2 + CO2) by in a double vessel type adsorption system by means of molecular sieves. This type of nitrogen generator is specially used in cases of high capacities and high purity.
Schematic process diagram with Inert Gas Generator,
Compressor cooler and CO2 stripper.
