Natural Gas Liquids Recovery Plant

A process for flexibly recovering NGLs from an inlet natural gas stream having a temperature at atmospheric ambient or higher and a pressure of at least 400 psig, comprising:

• a. passing the inlet natural gas stream as a tube side flow though a one-pass shell-and-tube first heat exchanger;
• b. passing inlet natural gas effluent from the tube side of the first heat exchanger as a tube side flow stream though a shell-and-tube second heat exchanger having a plurality of one-pass tubes;
• c. passing the inlet natural gas effluent from the tube side of the second heat exchanger through a NGLs condenser to reduce the temperature and pressure of the inlet natural gas at least sufficiently to condense NGLs in the inlet natural gas to two-phase gas-liquid NGLs;
• d. separating the two-phase gas-liquid NGLs in a gas-liquids separator from remaining single phase natural gas as a lean natural gas;
• e. passing the separated two-phase gas-liquid NGLs through a replaceable segment of a transfer line to the shell side of the first heat exchanger, said replaceable segment comprising either a length of pipe if no additional cooling of the two-phase gas-liquid NGLs is desired, or a J-T valve if additional cooling of the two-phase gas-liquid NGLs is desired;
• f. passing the two-phase gas-liquid NGLs from step (e) for counter-current flow to inlet natural gas in the tube side of the first heat exchanger at a shell side flow rate effective to increase the temperature of the shell side NGLs exiting the first heat exchanger to within a predetermine temperature range less than the temperature of the inlet natural gas entering the tube side of the first heat exchanger;
• g. regulating removal of NGLs from the shell side of the first heat exchanger to maintain a flow of NGLs passing to the shell side of the first heat exchanger;
• h. passing the separated lean natural gas to the shell side of the second heat exchanger;
• i. passing the separated lean natural gas from step (h) for counter-current flow to inlet natural gas in the tube side of the second heat exchanger at a shell side flow rate effective to increase the temperature of the shell side lean natural gas exiting the second heat exchanger to within a predetermine temperature range less than the temperature of the inlet natural gas entering the tube side of the second heat exchanger;
• and
• j. receiving separately NGLs removed from the shell side of the first heat exchanger and lean natural gas removed from the shell side of the second heat exchanger;
• k. while insulating the exterior of the shells of the first and second heat exchangers, the exterior of the separator, and passages within which the steps (c), (e), (f), and (h) are performed, to an extent sufficient to prevent condensation on the outer surfaces of the heat exchangers, the separator, and said passages at a temperature, in steps (a) and (b) in a range between the temperature of the fluid entering the shell side of the heat exchangers and the minimum temperature for which metallurgy of the separator is rated, in step (d), in a range between the temperature of the fluids entering the separator and the minimum temperature for which metallurgy of the separator is rated, and in steps (c), (e), (f), and (h), in a range between the temperature of the fluids in the passages and the minimum temperature for which metallurgy of the separator is rated.