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A continuous process for selective countercurrent extraction of C2+hydrocarbons from a natural gas stream with a physical solvent while at pipeline pressures to produce a residue natural gas stream meeting pipeline specifications and a liquid hydrocarbon product having a composition which can be rea

A continuous process for selective countercurrent extraction of C2+hydrocarbons from a natural gas stream with a physical solvent while at pipeline pressures to produce a residue natural gas stream meeting pipeline specifications and a liquid hydrocarbon product having a composition which can be readily adjusted to any selected degree in accordance with market conditions so that profitability of the extraction operation can be maximized at all times. The rich solvent is let down in pressure through successive flashing stages to produce a liquid product, and the stripped solvent is recirculated to the extraction step. The versatility of the process is achieved by using the following steps, in order of importance: (1) selectively varying the flow rate of the solvent with respect to the flow rate of the natural gas stream; (2) selectively varying the flashing pressure for one or more successive flashing stages; (3) recycling the flashed C1+undesirable gases to the extraction step; and (4) rejecting selected components of the liquid product in a stripping column for the liquid hydrocarbon product by: (a) selectively varying the pressure in the column, and (b) selectively varying the temperature at the bottom of the column. The rejected components are also recycled to the extraction step and are C1, C1+C2, C1+C2+C3, or C1+C2+C3+C4. If water is present in significant quantities, the solvent is regenerated before recycling it to the extraction step.

대표청구항 ▼

In a process for the removal of natural gas liquids comprising hydrocarbons heavier than methane from a natural gas stream, wherein a need exists for recovering to any selected degree and at extremely high recoveries a selected hydrocarbon component and heavier hydrocarbons within the group consisti

In a process for the removal of natural gas liquids comprising hydrocarbons heavier than methane from a natural gas stream, wherein a need exists for recovering to any selected degree and at extremely high recoveries a selected hydrocarbon component and heavier hydrocarbons within the group consisting of ethane, propane, butane, and pentane without the need simultaneously to recover hydrocarbons lighter than said selected hydrocarbon component from said natural gas stream, the improvement comprising: providing the capability of selectively extracting said natural gas liquids from said natural gas stream with a physical solvent according to said selected degree of (a) ethane in amounts ranging from 2-98%, (b) propane in amounts ranging from 2-99%, (c) butane in amounts ranging from 2-100%; or (d) pentanes and higher molecular weight hydrocarbons in amounts ranging up to 100% by: (1) contacting said natural gas stream with said physical solvent at flow rates within the range of 0.005-0.5 gallon of solvent per standard cubic foot of natural gas to produce a residue natural gas stream of pipeline specifications and a rich solvent stream containing ethane and heavier hydrocarbon components, said solvent being selective for ethane and heavier hydrocarbon components of the gas stream such that the relative volatility of methane over ethane is at least 5.0 and the hydrocarbon loading capacity, defined as solubility of ethane in solvent, is at least 0.25 standard cubic feet of ethane per gallon of solvent; (2) selectively flashing said rich solvent stream to produce a gas fraction and said solvent; and (3) compressing, cooling, and condensing said gas fraction to obtain said natural gas liquids.