The standard pump used to generate vacuum is the liquid ring type, with low costs and good reliability; the sealing liquid cooling can be made by air or through plate or tubular exchangers.

Dry vacuum is the solution if hydrocarbons to be recovered are soluble in the sealing liquid or if an issue is the energy low consumption; in these cases screw or rotary vanes vacuum pumps can be installed with lower power motor driven by inverter.

In all cases the vacuum can be improved by a Booster blower feeding the vacuum pump, increasing the vacuum degree and cutting the activated carbon regeneration time to meet stringent emission limits.