This article is concerned only with oils used as fuel for the purpose of heating and lighting. Oils are liquid fuel at most temperatures. In cold weather the viscosity of oils becomes greater and some oils develop problems which need to be considered. Liquid fuels tend to be more easily delivered since they can be pumped. Unlike solid fuels which require physical labor to move from source to truck to storage, a single man can transport and deliver a load of fuel without great effort or mess.

Oils are hydrocarbons, and as such they are combustible. Having high amounts of energy, oils are a potent source of heat. For good combustion, oils tend to need to be atomized to near aerosol particles.

In appliances that do not have a pump for atomization, a wick is used to vaporize the fuel for better combustion. Capillary action draws oil up the wick to the heat source for ignition. Once ignition occurs, the heat of the flame sustains the vaporization of the fuel. Oils tend to have a flash point that is considerably lower than the wick material.

Wicks can be a simple twist of cotton. Reeds have been used for wicks. Modern candle wicks are usually braided cotton. Lamp wicks are usually braided cotton as well, with the braid being wide and flat. Some wicks use a noncombustible fiber such as those used for mantles in in Coleman lamps and some wicks used in kerosene heaters.

Home Heating Oil

HHO is seldom if ever used in appliances other than home heating furnaces and boilers. Its low viscosity allows for wicking, but it is best used when atomized to near aerosol particules. HHO has many properties that are similar to diesel fuel since both have hydrocarbons with the same range of carbons per molecule. C14 to C20

Motor Oil

Motor oil maintains a high viscosity when heated. It has a fairly high flash point compared to other oils and so might never be used as a heating fuel. Yet if one were to preheat it and accept the poor combustion, motor oil could be used. C20 to C34

Kerosene

A particular distillate or fraction from petrochemicals such as coal or crude oil. As such it is not as volatile as gasoline. However, kerosene at times has been adulterated with less expensive hydrocarbons which have lower flash points or greater volatility. Kerosene was a trademarked name which became generically used for the product. In the UK, kerosene is called paraffin oil. C6 to C16

Liquid Paraffin

Liquid paraffin or paraffin oil as a fuel oil should not be confused with medicinal liquid paraffin, nor with paraffin wax. Both can also be used as fuel though the former has greater viscosity and the latter is a solid at room temperature. Liquid paraffin might also be used as an alternative name for mineral oil (C15 to C40). Paraffin is best used as a term to indicate a class of hydrocarbons known chemically as alkanes. Trade names and colloquialisms make this class name quite confusing. Paraffin oil and Liquid paraffin are both more viscous than kerosene. While they wick well, and are used in kerosene lamps they do not burn the same and can potentially cause problems.

Vegetable Oil

Vegetable oils have a wide array of viscosity. Generally they are too viscous to use in engines. Also called Pure Plant Oil in Europe, vegetable oil can also be used in lamps and furnaces. It wicks well, though can burn incompletely yielding sooty creosote. In furnaces it needs to be preheated to reduce its viscosity. It might also be cut with a more volatile solvent or hydrocarbon. Vegetable oils are derived from plants usually through a pressing process, though some are derived through a chemical process.

Biodiesel

This oil is derived from plants through a distillation process. Although any part of a plant may be used to make biodiesel, there is a trend away from using the food portion of a plant. This fuel is made through the process of pyrolysis and is actually a waste product from the production of methanol.

Animal Fat

When rendered and heated, animal fats are potent fuels. Often this food source has been used as a fuel. Most notable is Whale Oil which was widely used for lamps. Adipose tissue is a high calorie food. When having a significant greater amount of blood vessels, animal fat is called blubber. Animal fats (mostly blubber) were used in a wide array of industrial applications until petroleum products replaced them.

Where not common knowledge, Wikipedia was the sole source for facts in this article.

by: Zee-Man