Petroleum product

(materials) Materials derived from petroleum, natural gas, or asphalt deposits; includes gasolines, diesel and heating fuels, liquefied petroleum gases (LPG and bugas), lubricants, waxes, greases, petroleum coke, petrochemicals, and (from sour crudes and natural gases) sulfur.

Petroleum products are those fractions derived from petroleum that have commercial value as a bulk product. Petrochemicals, in contrast, are individual chemicals, derived from bulk fractions, that are used as the basic building blocks of the chemical industry. Gases and liquid fuels are currently the main products of the petroleum industry (see table). However, other products, such as lubricating oils, waxes, and asphalt, have also added to the value of petroleum resources. See also Petrochemical; Petroleum.

Petroleum products are hydrocarbon compounds, containing combinations of hydrogen and carbon with various molecular forms. Many compounds occur naturally. Other compounds are created by commercial processes for altering one combination to form another. Each combination has its unique set of chemical and physical properties. Specifications for petroleum products are based on properties such as density and boiling range to assure that a petroleum product can perform its intended task. See also Petroleum processing and refining.

Natural gas is predominantly methane (CH₄), which has the lowest boiling point and least complex structure of all hydrocarbons. Natural gas from an underground reservoir, when brought to the surface, may contain other, higher-boiling-point hydrocarbons, and is often referred to as wet gas. Wet gas is processed to remove the entrained hydrocarbons that are higher-boiling than methane. The high-boiling hydrocarbons that are isolated and liquefied are called natural gas condensates. See also Methane; Natural gas.

Gasoline (motor fuel) is a complex mixture of hydrocarbons that boils below 200°C (390°F) and is intended for most spark-ignition engines (such as those used in passenger cars, light-duty trucks, motorcycles, and motorboats). The properties of gasoline are intended to satisfy the requirements of smooth and clean burning, easy ignition in cold weather, minimal evaporation in hot weather, and stability during long storage periods. See also Gasoline; Internal combustion engine.

Petroleum naphtha is a generic term applied to refined, partly refined, or unrefined petroleum products. Naphthas are prepared by several methods, including (1) fractionation of distillates or crude petroleum, (2) solvent extraction, (3) hydrogenation of distillates, (4) polymerization of unsaturated (olefinic) compounds, and (5) alkylation processes. The naphtha may also be a combination of product streams from more than one process. The main uses of petroleum naphthas fall into the general areas of (1) solvents (diluents) for paints, (2) dry-cleaning solvents, (3) solvents for cutback asphalts, (4) solvents in rubber industry, and (5) solvents for industrial extraction processes. Turpentine, the traditional solvent for paints, has been almost completely replaced by the cheaper and more abundant petroleum naphthas. See also Naphtha; Solvent.

Kerosine is essentially a distillation fraction of petroleum. The quantity and quality of the kerosine vary with the type of crude oil; some crude oils yield excellent kerosine, while others produce kerosine that requires substantial refining. Kerosine is a very stable product, and additives are not required to improve the quality. Apart from the removal of excessive quantities of aromatics, kerosine fractions may need only a lye (alkali) wash if hydrogen sulfide is present. Kerosine is used as a fuel for heating and cooking, jet engines, and lamps, for weed burning, and as a base for insecticides. See also Kerosine.

Diesel fuel is a distillate product that has a higher boiling point than gasoline (or naphtha) but that also must self-ignite easily. This is determined through the cetane rating, derived from the reference fuel n-cetane. Cetane number is a measure of the tendency of a diesel fuel to knock in a diesel engine. The scale is based upon the ignition characteristics of two hydrocarbons, n-hexadecane (cetane) and 2,3,4,5,6,7,8-heptamethylnonane. Diesel fuel oil is essentially the same as furnace fuel oil, but the proportion of cracked gas oil is usually less since the high aromatic content of the cracked gas oil reduces the cetane value of the diesel fuel. See also Cetane number; Diesel engine; Diesel fuel.

Domestic fuel oil is used primarily in the home, and includes kerosine, stove oil, and furnace fuel oil. Stove oil is a straight-run (distilled) fraction from crude oil, whereas other fuel oils are usually blends of two or more fractions. The straight-run fractions available for blending into fuel oils are heavy naphtha, light and heavy gas oil, and residua. Cracked fractions such as light and heavy gas oil from catalytic cracking, cracking coal tar, and fractionator bottoms from catalytic cracking may also be used as blends to meet the specifications of the different fuel oils.

Heavy fuel oil includes a variety of oils, ranging from distillates to residual oils that must be heated to 260°C (500°F) or higher before they can be used. In general, heavy fuel oil consists of residual oil blended to suit specific needs and to meet designed specifications.

Heavy fuel oil usually contains residuum that is mixed (cut back) to a specified viscosity with gas oils and fractionator bottoms. For some industrial purposes where flames or flue gases contact the product (ceramics, glass, heat treating, open hearth furnaces), the fuel oil must be blended to have a minimum specified sulfur content. See also Fuel oil.

Asphalt is a residuum that cannot be distilled even under the highest vacuum since the temperatures required to volatilize the residuum promote the formation of coke. Asphalts have complex chemical and physical compositions that usually vary with the source of the crude oil. See also Asphalt and asphaltite.

Petroleum coke is the residue left by the noncatalytic destructive distillation (thermal decomposition with simultaneous removal of distillate) of petroleum residua. The coke formed in catalytic cracking operations is usually nonrecoverable because it adheres to the catalyst employed as fuel for the process. The composition of the coke varies with the source of the crude oil, but in general, large amounts of high-molecular-weight complex hydrocarbons (rich in carbon but correspondingly poor in hydrogen) make up a high proportion. Petroleum coke is employed for a number of purposes, but the major use is in the manufacture of carbon electrodes for aluminum refining, which requires a high-purity carbon (that is, low in ash and sulfur-free). In addition, petroleum coke is employed in the manufacture of carbon brushes, silicon carbide abrasives, and structural carbon (such as pipes and Rashig rings), as well as in the manufacture of calcium carbide (CaC₂) from which acetylene is produced. See also Coke.

It has been suggested that this article or section be merged with Petrochemical. (Discuss)

A petrochemical refinery in Grangemouth, Scotland.

Petroleum products are useful materials derived from crude oil (petroleum) as it is processed in oil refineries.

According to crude oil composition and demand, refineries can produce different shares of petroleum products. Largest share of oil products is used as energy carriers: various grades of fuel oil and gasoline. Refineries also produce other chemicals, some of which are used in chemical processes to produce plastics and other useful materials. Since petroleum often contains a couple of percent sulfur, large quantities of sulfur are also often produced as a petroleum product. Hydrogen and carbon in the form of petroleum coke may also be produced as petroleum products. The hydrogen produced is often used as an intermediate product for other oil refinery processes such as hydrogen catalytic cracking (hydrocracking) and hydrodesulfurization.

Major products of oil refineries

Asphalt Diesel fuel Fuel oils Gasoline Kerosene

Liquefied petroleum gas (LPG) Lubricating oils Paraffin wax Tar Petrochemicals (see discussion at end of next section)

Specialty end products

Oil refineries will blend various feedstocks, mix appropriate additives, provide short term storage, and prepare for bulk loading to trucks, barges, product ships, and railcars.

• Gaseous fuels such as propane, stored and shipped in liquid form under pressure in specialized railcars to distributors.
• Liquid fuels blending (producing automotive and aviation grades of gasoline, kerosene, various aviation turbine fuels, and diesel fuels, adding dyes, detergents, antiknock additives, oxygenates, and anti-fungal compounds as required). Shipped by barge, rail, and tanker ship. May be shipped regionally in dedicated pipelines to point consumers, particularly aviation jet fuel to major airports, or piped to distributors in multi-product pipelines using product separators called pipeline inspection gauges ("pigs").
• Lubricants (produces light machine oils, motor oils, and greases, adding viscosity stabilizers as required), usually shipped in bulk to an offsite packaging plant.
• Wax (paraffin), used in the packaging of frozen foods, among others. May be shipped in bulk to a site to prepare as packaged blocks.
• Sulfur (or sulfuric acid), byproducts of sulfur removal from petroleum which may have up to a couple percent sulfur as organic sulfur-containing compounds. Sulfur and sulfuric acid are useful industrial materials. Sulfuric acid is usually prepared and shipped as the acid precursor oleum.
• Bulk tar shipping for offsite unit packaging for use in tar-and-gravel roofing or similar uses.
• Asphalt - used as a binder for gravel to form asphalt concrete, which is used for paving roads, lots, etc. An asphalt unit prepares bulk asphalt for shipment.
• Petroleum coke, used in specialty carbon products such as certain types of electrodes, or as solid fuel.
• Petrochemicals or petrochemical feedstocks, which are often sent to petrochemical plants for further processing in a variety of ways. The petrochemicals may be olefins or their precursors, or various types of aromatic petrochemicals.

Petrochemicals have a vast variety of uses. They are commonly used as monomers or feedstocks for monomer production. Olefins such as alpha-olefins and dienes are often used as monomers, although aromatics can also be used as monomer precursors. The monomers are then polymerized in various ways to form polymers. Polymer materials can be used as plastics, elastomers, or fibers, or possibly some intermediate form of these material types. Some polymers are also used as gels or lubricants. Petrochemicals can also be used as solvents or as feedstock for producing solvents. Petrochemicals can also be used as precursors for a wide variety of chemicals and substances such as vehicle fluids, surfactants for cleaners, etc.

See also

• Lanolin - lanolin based products are a natural alternative to toxic petro-chemical sprays and degreasers

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