Heating oil

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Heating oil, or oil heat, also known in the United States as No. 2 heating oil, is a low viscosity, flammable liquid petroleum product used to fuel building furnaces or boilers. In the U.S. it must conform to ASTM standard D396. Diesel and kerosene, while often confused as being similar or identical, must conform to their own respective ASTM standards.

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 basement, garage, or outside adjacent to the building. It is sometimes stored in underground storage tanks (or "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.

Heating oil is widely used in parts of the U.S. and Canada where natural gas or propane is frequently not available. Where other fuels are not available, it is sometimes referred to as the unit cost per unit (BTU=British Themal Unit or BTUH / h per hour), and can be less than other fuels. Boiler and "forced air" furnace manufacturers have perfected "retention head oil-fired burners" and "triple-pass flue" boilers that have increased theoretical oil burner efficiency to over 93%. To reach that level of efficiency however, would require a lower flue gas temperature that most oil burners cannot produce . Therefore causing condensation that most oil-fired furnaces cannot handle without damage to the heat exchanger, venting pipes or outside casing of the appliance . Practical efficiency is typically around 86%.

Red dyes are usually added, resulting in its "red diesel" name in countries like United Kingdom. Solvent Yellow 124 is added as a "Euromarker" since 2002 in European Union.

Heating oil is very similar to diesel fuel, and both are classified as distillates. It consists of a mixture of petroleum-derived hydrocarbons in the 14- to 20-carbon atom range. That is, heating oil's chemical formula is usually either C₁₄H₃₀, C₁₅H₃₂, C₁₆H₃₄, C₁₇H₃₆, C₁₈H₃₈, C₁₉H₄₀, or C₂₀H₄₂. During oil distillation, it condenses at between 250 °C and 350 °C. Heating oil condenses at a lower temperature than the heavy (C20+) hydrocarbons such as petroleum jelly, bitumen, candle wax, and lubricating oil, which condense between 340 °C and 400 °C. But it condenses at a higher temperature than kerosene, which condenses between 160 °C and 250 °C.

For efficient burning, the oil is drawn/pulled from the tank into a pump and pressurized (residential) to 100-140 psi and then forced through a filtered (specific to appliance) nozzle, into an "atomized" spray pattern . It is then ignited through the use of a "step-up" transformer . Taking 120 volts(AC) and stepping it up to 10,000 volts . The voltage travels down two brass conductors (buzz bars) to the metal/ceramic electrodes and produces a spark approximately 1/4 inches across . With the airflow coming from the "squirrel cage" of the oil-burner, the spark ignites the oil droplets . Through the use of a "combustion chamber", the flame is contained, and "flue gases" travels through the "heat exchanger" . The heat of the flue gases is transferred through the walls of the heat exchanger as they pass to the chimney, and the fan/blower unit circulates the heat of the heat exchanger throughout the house . With a cold air return generally in the center of the house supplying all or most of the cold air that is return to the furnace for re-heating .

Heating oil produces 138,500 BTU per gallon and weighs 7.2 pounds per imperial gallon (0.72 kg/l), which is about the same heat per unit mass as the somewhat less dense diesel fuel. Number 2 fuel oil has a flash point of 52 °C.

Leaks from tanks and piping are an environmental concern. 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.

Heating oil may be blended with biofuel to create a product similar to biodiesel known as "bioheat".

[edit] Heating oil trade

Heating oil accounts for about 25% of the yield of a barrel of crude oil, the second largest "cut" after gasoline (petrol). The heating oil futures contract trades in units of 42,000 U.S. gallons (1,000 barrels) and (for the USA) is based on delivery in the New York harbor. Options on futures, calendar spread options contracts, crack spread options contracts, and average price options contracts give market participants even greater flexibility in managing price risk.

The heating oil futures contract is also used to hedge diesel fuel and jet fuel, both of which trade in the cash market at an often stable premium to NYMEX Division New York Harbor heating oil futures.