Abstract: An improved system for separating higher boiling hydrocarbon products from methane in a gas/liquid extraction plant. The improvements lies in combining the fractionating tower with a counterflow plate and tube heat exchanger through which the refrigerated low pressure gas flows from top end to bottom end, and the precooled high pressure gas flows upwardly in counterflow relation. The heat exchanger is in the form of an annular chamber with tubes running the full length from bottom to top and plates forcing a zig-zag flow of the cold gas. This sets up a more or less linear temperature gradient which is impressed on the fractionating tower inside of the heat exchanger, which forms the inner wall of the heat exchanger and makes for more efficient and effective fractionation of the entering gas and vapor mixture.

Abstract: A gas treating unit that uses external refrigeration to cool a high pressure stream of natural gas condenses and separates at substantially pipeline pressures higher boiling point hydrocarbons from pipeline gas. The pipeline gas is heated by heat transfer with the refrigerant to substantially pipeline temperature and delivered to a sales gas line. The condensed higher boiling point hydrocarbons are cooled by expansion in a Joule-Thompson expansion to provide cooling for the condenser of a fractionating tower into which the condensed hydrocarbons are charged as feed for stripping volatile components therefrom to produce a liquid product of acceptable vapor pressure. Heat from the compression of the refrigerant is used to supply heat to the reboiler for the fractionating tower.

Abstract: Ethane and other hydrocarbons of higher boiling point are separated as a liquid from natural gas to leave a gas consisting principally of methane for delivery to a pipeline. The natural gas is passed in countercurrent heat exchange with the liquid product and with the pipeline gas to cool the natural gas to a temperature at which a major part of the ethane is condensed. The condensed ethane and higher boiling point hydrocarbons are separated from uncondensed vapors in the natural gas and the vapors are expanded to a low pressure and delivered into the upper end of a fractionating tower. The condensate is expanded to the same pressure and introduced into the fractionating tower at a midpoint thereof. Gases discharged overhead from the fractionating tower constitute the pipeline gas that is returned to the heat exchanger for countercurrent heat exchange with the natural gas.