Natural gas can be fractionated into various streams through a process known as natural gas processing or natural gas fractionation. This process involves separating different components of the natural gas mixture based on their physical properties. Here are some common ways in which natural gas can be fractionated:
Separation of Condensable Liquids: Natural gas often contains condensable hydrocarbons such as propane, butane, and natural gasoline. These liquids can be separated from the gas stream through cooling and compression. The process is typically carried out in a fractionation column, where the gas is cooled and condensed, allowing the separation of different hydrocarbon components based on their boiling points.
Removal of Water and Impurities: Natural gas may contain water vapor, sulfur compounds, and other impurities that need to be removed. Processes such as dehydration and amine treating are employed to remove water and acid gases from the gas stream.
Extraction of Natural Gas Liquids (NGLs): Natural gas liquids, including ethane, propane, butane, and pentane, can be extracted from the natural gas stream. This is often done through processes like cryogenic extraction or absorption, which involve cooling the gas stream to very low temperatures to separate and capture the desired NGL components.
Separation of Methane: Methane, which is the primary component of natural gas, can be separated and purified to obtain pipeline-quality gas. This involves additional treatment steps, such as acid gas removal, dehydration, and further purification through molecular sieves or membrane separation.
Fractionation of NGLs: Once the NGLs are extracted, further fractionation processes can be employed to separate them into individual components such as ethane, propane, butane, and natural gasoline. This is typically done through distillation, where the NGL mixture is heated and passed through fractionation columns to separate the components based on their boiling points.
Each of these fractionation processes contributes to the overall processing of natural gas, allowing for the extraction and purification of valuable components for various applications, including heating, power generation, industrial uses, and as feedstocks for petrochemical industries.