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Heating oil

Liquid petroleum product used as a fuel oil for furnaces or boilers

  • 6 min read
  • 4 chapters

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Through Viscosity, European Union and Municipality

Most heating oil products are chemically very similar to diesel fuel used as motor fuel; motor fuel is typically subject to higher fuel taxes. Many countries add fuel dyes to heating oil, allowing law enforcement to check if a driver is evading fuel taxes. Since 2002, Solvent Yellow 124 has been added as a "Euromarker" in the European Union; untaxed diesel is known as "red diesel" in the United Kingdom.

Heating oil is commonly delivered by tank truck to residential, commercial, and municipal buildings and stored in above-ground storage tanks (ASTs) located in the basements, garages, or outside adjacent to the building. It is sometimes stored in underground storage tanks (USTs) but less often than ASTs. ASTs are used for smaller installations due to the lower cost factor. Heating oil is less commonly used as an industrial fuel or for power generation.

Leaks from tanks and piping are an environmental concern. In the United States, various federal and state regulations are in place regarding the proper transportation, storage and burning of heating oil, which is classified as a hazardous material (HazMat) by federal regulators.

Technical characteristics

Heating oil consists of a mixture of petroleum-derived hydrocarbons in the 14- to 20-carbon atom range that condense between 250 and 350 °C (482 and 662 °F) during oil refining. Heating oil condenses at a lower temperature than petroleum jelly, bitumen, candle wax, and lubricating oil, but at a higher temperature than kerosene, which condenses between 160–250 °C (320–482 °F). The heavy (C20+) hydrocarbons condense between 340–400 °C (644–752 °F).

Heating oil produces 137,500 British thermal units per US gallon (38.3 MJ/L) to 138,700 British thermal units per US gallon (38.7 MJ/L) and weighs 7.2 (7.38) pounds per US gallon (0.95 kg/L). Number 2 fuel oil has a flash point of 52 °C (126 °F).

Historically, the legal difference between diesel and heating oil in the United States has been sulfur allowance. Diesel for machinery and equipment must be below 15 ppm sulfur content while heating oil needed only stay below 500 ppm sulfur. However, most heating oil in the United States is now "ultra-low sulfur heating oil" (ULSHO) and meets the same 15 ppm standard.

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