Depending on who you talk to, the definition of “hydrocarbon liquid” may vary. Some educators may try to limit the label to crude oil, preferring to use more specific terms for liquid hydrocarbons transitioned from a gas state instead, including “condensate” and “natural gas liquids” (NGLs). Yet others, like the U.S. Energy Information Administration (EIA), prefer blanket terms like “hydrocarbon gas liquids” to describe the entire category of plant liquids and liquefied refinery gases while excluding liquefied natural gas (LNG). Whatever terms you prefer, liquefied forms of hydrocarbons have kept modern society in motion for many decades, but what are their uses in modern times?
As a hydrocarbon liquid, crude oil has many applications. It’s predominately fractionated and refined to create fuel oils and gasoline. However, fractions of crude oil can be applied to the creation of other modern materials, from asphalt to lubricants and paraffin wax to petrochemicals. Additionally, thousands of items can be manufactured from petroleum by-products, including fertilizer, insecticide, and house paint.
However, oil is not the only hydrocarbon in liquid form. The methane of natural gas as well as the hydrocarbon component molecules extracted from natural gas can be liquefied for more efficient processing and distribution. “Wet” natural gas containing measurable amounts of ethane, propane, and butane is processed with techniques like absorption or controlled expansion through a distillation column. The methane leaves as a gas, and the natural gas liquids (NGLs) drop out from the column to be processed for separation at a fractionation plant.
The methane is sold as natural gas for heating and fuel. Once separated, ethane is primarily used in the chemical industry as a feedstock for other chemical commodities or as a refrigerant. Propane is used as a heating and cooking fuel, motor fuel, and refrigerant as well as in soldering applications. Butane and its various forms end up in gasoline blends, fuel, and refrigerants as well as feedstock in the creation of synthetic rubber.
One other component found as a fraction from NGL processing is “natural gasoline,” composed primarily of pentanes and heavier hydrocarbons. Its primary use is as an ethanol additive to create blended automotive fuels like E85.