An important variable that determines the size of a given desiccant bed is the relative saturation of the inlet gas. This variable is the driving force that affects the transfer of water to the adsorbent. If saturated gas (100% relative humidity) is being dried, higher useful capacities can be expected for most desiccants than when drying partially saturated gases. However, in most field gas dehydration installations the inlet gas is saturated with water vapor and this is not a variable that must be considered.
