Stabilization of Petroleum

the removal of the residual gaseous hydrocarbons and light liquid fractions from petroleum after the initial degasification. The process is carried out at oil fields or at main pumping stations as the petroleum leaves the well. In stabilized petroleum, the content of dissolved gases does not exceed 1–2 percent. The gaseous hydrocarbons are transferred to gas-treatment plants, and the stabilized petroleum, to petroleum refineries.

In an installation for petroleum stabilization (Figure 1), the feed is heated to 200°-250°C in heat exchangers and then transferred to a fractionation column, where the pressure is 0.2–0.5 meganewton per sq m (MN/m²). From here, the gaseous hydrocarbons and vapors of light gasoline (natural gasoline) are conducted to a cooling condenser and then to a gas separator; the uncondensed gases are transferred to gas-treatment plants, while part of the liquid phase is returned to the fractionation column as reflux. The rest of the liquid phase enters a heat exchanger, from which, after heating, it passes to a fractionation column having a pressure of 0.8–1.2 MN/m². From the column, the gaseous hydrocarbons are carried to a cooling condenser and then to a gas separator. Dry gas is withdrawn from the upper part of the separator, while the liquefied propane-butane fraction is withdrawn from the lower part. Part of this fraction is returned to the column as reflux, with the balance being fed into a tank. Stabilized petroleum is thus obtained from the columns, and gasoline from the heat exchangers and condensers. For a more thorough separation of the light fractions, the columns are heated from below.

Figure 1. Design of an installation for the stabilization of petroleum: (1) and (5) heat exchangers, (2) and (6) fractionation columns, (3) and (7) cooling condensers, (4) and (8) gas separators, (9) reboilers, (I) petroleum feed, (II) stabilized petroleum, (III) stabilized natural gasoline, (IV) dry gas, and (V) liquefied propane-butane fraction