Figure 6-1 shows a multistage separation process. By removing molecules of the light components in the first separator they are not available to flash to gas from the liquid in the second separator, and the partial pressure of intermediate components in the second separator is higher than it would have been if the first separator did not exist. The second separator serves the same function of increasing the partial pressure of the intermediate components in the third separator and so forth.
The simplest form of condensate stabilization is to install a low-pressure separator downstream of an initial high-pressure separator. Unless the gas well produces at low pressure (less than 500 psi) and the gas contains very little condensate (less than 100 bpd), the additional expenditure for this stage of separation is almost always economical when balanced against increased liquid production. If vapor recovery from the tank is required by environmental regulations, the flash separator will significantly reduce the horsepower required. If vapor recovery is not required, the gas from the flash separator may be economically feasible to be recovered and recompressed for sales even if it is not feasible to recover stock tank vapors.