Well fluids are a complex mixture of liquid hydrocarbons, gas, water, and some impurities. The water and impurities must be removed before the hydrocarbons are stored, transported, and sold. Liquid hydrocarbons and objectionable impurities must also be removed from natural gas before gas goes to a sales line. A separator is a piece of equipment used to separate wellstream gas from free liquids. The size of the separator depends on the rate of natural gas flow and/or liquids going into the vessel.