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Jai Ganesh

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Registered: 2005-06-28

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Re: Miscellany

2426) Naphtha

Gist

Naphtha is a flammable liquid mixture of hydrocarbons, primarily derived from crude oil distillation, that serves as a crucial feedstock and fuel in various industries. It is used to produce high-octane gasoline, petrochemicals for plastics, fertilizers, and is also used as a solvent and for fuels like lighter fluid or camp stoves. Due to its flammability, it must be handled with care, and its vapor is heavier than air and can travel to an ignition source.

The main uses of crude oil naphtha fall into the general areas of (i) precursor to gasoline and other liquid fuels, (ii) solvents or diluents for paints, (iii) dry-cleaning solvents, (iv) solvents for cutback asphalt, (v) solvents in rubber industry, and (vi) solvents for industrial extraction processes.

Summary

Naphtha is any of various volatile, highly flammable liquid hydrocarbon mixtures used chiefly as solvents and diluents and as raw materials for conversion to gasoline. Naphtha was the name originally applied to the more volatile kinds of petroleum issuing from the ground in the Baku district of Azerbaijan and Iran. As early as the 1st century ad, naphtha was mentioned by the Greek writer Dioscorides and the Roman writer Pliny the Elder. Alchemists used the word principally to distinguish various mobile liquids of low boiling point, including certain ethers and esters.

In modern usage the word naphtha is usually accompanied by a distinctive prefix. Coal-tar naphtha is a volatile commercial product obtained by the distillation of coal tar. Shale naphtha is obtained by the distillation of oil produced from bituminous shale by destructive distillation. Petroleum naphtha is a name used primarily in the United States for petroleum distillate containing principally aliphatic hydrocarbons and boiling higher than gasoline and lower than kerosene.

Details

Naphtha is a flammable liquid hydrocarbon mixture. Generally, it is a fraction of crude oil, but it can also be produced from natural-gas condensates, petroleum distillates, and the fractional distillation of coal tar and peat. In some industries and regions, the name naphtha refers to crude oil or refined petroleum products such as kerosene or diesel fuel.

Naphtha is also known as Shellite in Australia.

Modern period

Since the 19th century, solvent naphtha has denoted a product (xylene or trimethylbenzenes) derived by fractional distillation from petroleum; these mineral spirits, also known as "Stoddard Solvent," were originally the main active ingredient in Fels Naptha laundry soap. The naphtha in Fels Naptha was later removed as a cancer risk.

The usage of the term "naphtha" during this time typically implies petroleum naphtha, a colorless liquid with a similar odor to gasoline. However, "coal tar naphtha," a reddish brown liquid that is a mixture of hydrocarbons (toluene, xylene, and cumene, etc.), could also be intended in some contexts.

Petroleum

In older usage, "naphtha" simply meant crude oil, but this usage is now obsolete in English. There are a number of cognates to the word in different modern languages, typically signifying "petroleum" or "crude oil."

The Ukrainian & Belarusian word (nafta), Lithuanian, Latvian, & Estonian "nafta," and the Persian naft mean "crude oil." The Russian word (neft') means "crude oil," but (nafta) is a synonym of ligroin. Also, in Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Finland, Italy, Serbia, Slovenia, and Macedonia nafta (нафта in Cyrillic) is colloquially used to indicate diesel fuel and crude oil. In the Czech Republic and Slovakia, nafta was historically used for both diesel fuel and crude oil, but its use for crude oil is now obsolete and it generally indicates diesel fuel. In Bulgarian, nafta means diesel fuel, while neft, as well as petrol (петрол in Cyrillic), means crude oil. Nafta is also used in everyday parlance in Argentina, Uruguay and Paraguay to refer to gasoline/petrol. Similarly, in Flemish, the word naft(e) is used colloquially for gasoline. In Poland, the word nafta means kerosene, and colloquially crude oil (the technical name for crude oil is ropa naftowa, also colloquially used for diesel fuel as ropa).

Types

Naphtha has been divided into two types by many sources in order to differentiate between common grades more clearly:

One source distinguishes by boiling point as well as carbon atom count per molecule:

* Light naphtha is the fraction boiling between 30 and 90 °C (86 and 194 °F) and consists of molecules with 5–6 carbon atoms.
* Heavy naphtha boils between 90 and 200 °C (194 and 392 °F) and consists of molecules with 6–12 carbon atoms.

Chemistry of Hazardous Materials differentiates light and heavy based on the carbon atom count and hydrocarbon structure:

* Light [is] a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from five to six carbon atoms per molecule.
* Heavy [is] a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from seven to nine carbon atoms per molecule.

Some sources also define petroleum naphtha, which contains both heavy and light naphtha, and typically consists of 15-30% of crude oil by weight.

Uses:

Heavy crude oil dilution

Naphtha is used to dilute heavy crude oil to reduce its viscosity and enable/facilitate transport; undiluted heavy crude cannot normally be transported by pipeline, and may also be difficult to pump onto oil tankers. Other common dilutants include natural-gas condensate and light crude. However, naphtha is a particularly efficient dilutant and can be recycled from diluted heavy crude after transport and processing. The importance of oil dilutants has increased as global production of lighter crude oils has fallen and shifted to exploitation of heavier reserves.

Fuel

Light naphtha is used as a fuel in some commercial applications. One notable example is wick-based cigarette lighters, such as the Zippo, which draw "lighter fluid"—naphtha—into a wick from a reservoir to be ignited using the flint and wheel.

It is also a fuel for camping stoves and oil lanterns, known as "white gas", where naphtha's low boiling point makes it easy to ignite. Naphtha is sometimes preferred over kerosene because it clogs fuel lines less. The outdoor equipment manufacturer MSR published a list of trade names and translations to help outdoor enthusiasts obtain the correct products in various countries.

Naphtha was also historically used as both a fuel and a working fluid in some small boats where steam technology was impractical; most were built to circumvent safety laws relating to traditional steam launches.

As an internal combustion engine fuel, petroleum naphtha has seen very little use and suffers from lower efficiency and low octane ratings, typically 40 to 70 RON. It can be used to run unmodified diesel engines, though it has a longer ignition-delay than diesel. Naphtha tends to be noisy in combustion due to the high pressure rise rate. There is a possibility of using naphtha as a low-octane base fuel in an octane-on-demand concept, with the engine drawing a high-octane mix only when needed. Naptha benefits from lesser emissions in refinement: fuel energy losses from "well-to-tank" are 13%; lower than the 22% losses for petroleum.

Plastics

Naphtha is a crucial component in the production of plastics.

Additional Information

Naphtha is a term used to refer to a group of volatile, flammable mixtures of liquid hydrocarbons that are used mainly as solvents, diluents, or raw materials for gasoline conversion. It is a lightweight petrochemical feedstock that is separated from crude oil in the fractional distillation process along with kerosene and jet fuel.

There are many specific types of naphtha that vary in the amounts and types of hydrocarbons contained in their unique blend. Refineries can produce various forms of naphtha, and each has specific guidelines in how it should be handled and stored. Generally speaking, the flammability and volatility of naphtha should be taken into consideration as they are significant safety hazards.

Uses and Safety

As mentioned above, naphtha is commonly used as a solvent. It is used in hydrocarbon cracking, laundry soaps, and cleaning fluids. Naphtha is also used to make varnishes, and sometimes is used as a fuel for camp stoves and as a solvent (diluent) for paint. Although naphtha has many uses, some forms of it can be dangerous. Many kinds of naphtha can cause skin irritation, upset stomachs, and other health problems if people are exposed to them. Some forms are also carcinogens, and thus inhalation or ingestion of the chemical should be avoided.

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