Natural Gas Liquids (NGLs) are hydrocarbon components of natural gas that are extracted from the gas state in the form of liquids. These liquids include propane, butane, isobutane, ethane, and natural gasoline. The extraction and separation of NGLs from natural gas occur at natural gas processing plants or refineries and involve various processes like absorption, refrigeration, and cryogenic methods.
Types of Natural Gas Liquids
Ethane (C2H6)
Ethane is primarily used as a petrochemical feedstock for ethylene production, which is further processed into plastics, antifreeze, and detergents.
Propane (C3H8)
Propane is used for heating, cooking, and as a fuel for engines. It is also used as a feedstock in petrochemical processes.
Butane (C4H10)
Butane has applications in fuel for lighters, portable stoves, and as a fuel propellant in aerosol sprays. It’s also used in the blending of gasoline to boost octane levels.
Isobutane (i-C4H10)
Isobutane is commonly used in refineries to enhance the octane rating of gasoline. It is also an essential component in refrigeration systems.
Natural Gasoline (Pentanes Plus/Super Light Oil)
Natural gasoline, also known as pentanes plus, is used as a blending agent in fuels, a diluent for heavy crude oil, and a feedstock for the petrochemical industry.
Production and Separation Processes
Absorption
In absorption, NGLs are separated from the natural gas through contact with a liquid absorption agent that selectively absorbs the heavier hydrocarbons.
Refrigeration
Refrigeration methods cool the natural gas to condense NGLs below their boiling points, separating them from the methane.
Cryogenic Processes
Cryogenic processing involves lowering the temperature to about -120°F to -150°F to liquefy the NGLs while keeping methane in the gaseous state.
Applications and Examples
NGLs find wide-ranging applications in different industries:
- Manufacturing: Ethane and propane as feedstocks for the production of plastics and solvents.
- Energy: Propane and butane as fuels for heating, cooking, and transportation.
- Refrigeration: Isobutane in cooling systems.
- Fuel Blending: NGLs are blended into gasoline to enhance performance and meet environmental regulations.
Historical Context
The extraction and utilization of NGLs have evolved considerably over the last century. Initially, NGLs were often flared off as waste. However, advancements in technology and a growing demand for energy and petrochemical products have transformed NGLs into valuable commodities.
Comparisons with Related Terms
- Liquefied Natural Gas (LNG): Unlike NGLs, LNG is natural gas (primarily methane) cooled to a liquid state for ease of storage and transportation.
- Natural Gas: A gaseous mixture principally composed of methane, from which NGLs are extracted.
FAQs
What is the main difference between NGL and LNG?
How are NGLs transported?
Are NGLs environmentally friendly?
References
- Smith, J. M., “Natural Gas Processing: Technology and Engineering Design,” Elservier Press, 2013.
- “API Recommended Practice 551: Process Measurement Instrumentation,” American Petroleum Institute, 2017.
Summary
Natural Gas Liquids (NGLs) play a vital role in the energy and petrochemical industries. Their diverse types, such as ethane, propane, butane, isobutane, and natural gasoline, have unique applications ranging from fuel sources to petrochemical feedstocks. Advances in technology have made the extraction and utilization of NGLs a crucial aspect of modern energy production and industrial processes.
