Petroleum Products

Petroleum is a naturally occurring, yellow-to-black liquid found in geological formations beneath the Earth’s surface, which is commonly refined into various types of fuels.

It consists of hydrocarbons of various molecular weights and other organic compounds.The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, usually zooplankton and algae, are buried underneath sedimentary rock and subjected to intense heat and pressure.

Petroleum is recovered mostly through oil drilling (natural petroleum springs are rare). This comes after the studies of structural geology (at the reservoir scale), sedimentary basin analysis, reservoir characterization (mainly in terms of the porosity and permeability of geologic reservoir structures). It is refined and separated, most easily by distillation, into a large number of consumer products, from gasoline (petrol) and kerosene to asphalt and chemical reagents used to make plastics and pharmaceuticals.Petroleum is used in manufacturing a wide variety of materials,and it is estimated that the world consumes about 90 million barrels each day.

Jet fuel, aviation turbine fuel (ATF), or avtur, is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is colourless to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1, which are produced to a standardized international specification. The only other jet fuel commonly used in civilian turbine-engine powered aviation is Jet B, which is used for its enhanced cold-weather performance.

Jet fuel is a mixture of a large number of different hydrocarbons. The range of their sizes (molecular weights or carbon numbers) is restricted by the requirements for the product, for example, the freezing point or smoke point. Kerosene-type jet fuel (including Jet A and Jet A-1) has a carbon number distribution between about 8 and 16 (carbon atoms per molecule); wide-cut or naphtha-type jet fuel (including Jet B), between about 5 and 15.

Fuel oil or heavy oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid fuel that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash point of approximately 40 °C (104 °F) and oils burned in cotton or wool-wick burners. In this sense, diesel is a type of fuel oil. Fuel oil is made of long hydrocarbon chains, particularly alkanes, cycloalkanes and aromatics. The term fuel oil is also used in a stricter sense to refer only to the heaviest commercial fuel that can be obtained from crude oil, i.e., heavier than gasoline and naphtha.

Biodiesel refers to a vegetable oil – or animal fat-based diesel fuel consisting of long-chain alkyl (methyl, ethyl, or propyl) esters.

Biodiesel is meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils used to fuel converted diesel engines. Biodiesel can be used alone, or blended with petrodiesel in any proportions. Blends of biodiesel and conventional petroleum derived diesel are products most commonly distributed for use in the retail diesel fuel marketplace.

Gasoline, also known as petrol outside of North America, is a transparent, petroleum-derived liquid that is used primarily as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives.

On average, a 42-gallon barrel of crude oil yields about 19 gallons of gasoline when processed in an oil refinery, though this can and does vary based on the crude oil source’s assay.

The characteristic of a particular gasoline blend to resist igniting too early is measured by its octane rating. Gasoline is produced in several grades of octane rating. Tetraethyllead and other lead compounds are no longer used in most areas to regulate and increase octane-rating, but many other additives are put into gasoline to improve its chemical stability, control corrosiveness and provide fuel system ‘cleaning,’ and determine performance characteristics under intended use. Sometimes, gasoline also contains ethanol as an alternative fuel, for economic or environmental reasons.

Petroleum Products 3

Diesel Fuel Grades

Historically, the quality of automotive fuels in the United States was specified by ASTM standards. Diesel fuels are covered by the ASTM D975 standard. Since 2004, the D975 standard has covered seven grades of diesel, Table 1. Heavier fuel oils Grade 5 and 6 (residual), which are used primarily for heating purposes, are described by ASTM D396.

Table 1
Diesel Fuel Grades

Grade

Description

Max Sulfur

No. 1-D S15 A special-purpose, light middle distillate fuel for use in diesel engine applications with frequent and widely varying speeds and loads or when abnormally low operating temperatures are encountered. Higher volatility than that provided by No. 2-D fuels. 15 ppm
No. 1-D S500 500 ppm
No. 1-D S5000 5000 ppm
No. 2-D S15 A general-purpose, middle distillate fuel for use in diesel engines, especially in applications with relatively high loads and uniform speeds, or in diesel engines not requiring fuels having higher volatility or other properties specified in Grade No. 1-D fuels. 15 ppm
No. 2-D S500 500 ppm
No. 2-D S5000 5000 ppm
No. 4-D A heavy distillate fuel, or a blend of distillate and residual oil, for low- and medium-speed diesel engines in applications involving predominantly constant speed and load.

The Sxxx designation was first adopted in the D975-04 edition of the standard to distinguish grades by sulfur content. The S5000 grades correspond to the “regular” sulfur grades, the previous No. 1-D and No. 2-D. S500 grades correspond to the previous “Low Sulfur” grades (D975-03). S15 grades are commonly referred to as “Ultra-Low Sulfur” grades or ULSD

An ASTM standard (D2069) once existed for marine diesel fuels, but it has been withdrawn. It was technically equivalent to ISO 8217. While some marine diesel engines use No. 2 distillate, D2069 covered four kinds of marine distillate fuels: DMX, DMA, DMB, and DMC and residual fuels (see also ISO marine fuel specifications):

  • DMX is a special light distillate intended mainly for use in emergency engines.
  • DMA (also called marine gas oil, MGO) is a general purpose marine distillate that must be free from traces of residual fuel. DMX and DMA fuels are primarily used in Category 1 marine engines (< 5 liters per cylinder).
  • DMB (marine diesel oil, MDO) is allowed to have traces of residual fuel, which can be high in sulfur. This contamination with residual fuel usually occurs in the distribution process, when using the same supply means (e.g., pipelines, supply vessels) that are used for residual fuel. DMB is produced when fuels such as DMA are brought on board the vessel in this manner. DMB is typically used for Category 2 (5-30 liters per cylinder) and Category 3 (≥ 30 liters per cylinder) engines.
  • DMC is a grade that may contain residual fuel, and is often a residual fuel blend. It is similar to No. 4-D, and can be used in Category 2 and Category 3 marine diesel engines.
  • Residual (non-distillate) fuels are designated by the prefix RM (e.g., RMA, RMB, etc.). These fuels are also identified by their nominal viscosity (e.g., RMA10, RMG35, etc.).

With the growing importance of alternative diesel fuels, standards have also been developed for biodiesel fuels and their blends. Sulfur Content

Since the 1990’s, fuel quality has been increasingly more regulated by the US EPA under the authority of the Clean Air Act. In the context of the increasingly more stringent diesel emission standards, the most important fuel property regulated by the EPA became the sulfur content. Historically, the sulfur content in diesel fuels for highway and nonroad vehicles was limited to 0.5% (wt.) by ASTM specifications. The milestones in US environmental regulations limiting sulfur levels in diesel fuels can be summarized as follows:

  • Highway Diesel Fuel
  • 500 ppm: Sulfur limit of 500 ppm = 0.05% (wt.) became effective in October 1993. This fuel, commonly referred to as low sulfur diesel fuel, was introduced to facilitate sulfate particulate emission reductions, which were necessary for meeting the 1994 emission standards for heavy-duty highway engines.
  • 15 ppm: Diesel fuel of maximum sulfur level of 15 ppm was available for highway use beginning in June 2006. This fuel, referred to as ultra low sulfur diesel (ULSD), was legislated by the EPA to enable catalyst-based emission control devices, such as diesel particulate filters and NOx adsorbers necessary for meeting the 2007-2010 emission standards for heavy-duty engines and the Tier 2 light-duty standards.
  • Nonroad Diesel Fuel
    The following sulfur requirements are applicable to Nonroad, Locomotive and Marine (NRLM) fuels, with the exception of heavy fuel oils (HFO) used in Category 2 and Category 3 marine diesel engines.
  • 500 ppm: Sulfur limit of 500 ppm became effective in June 2007 for nonroad, locomotive and marine fuels.
  • 15 ppm: Sulfur limit of 15 ppm (ULSD) becomes effective in June 2010 for nonroad fuel, and in June 2012 for locomotive and marine fuels. ULSD has been legislated for nonroad engines to enable advanced emission control systems for meeting the Tier 4 nonroad emission standards.
  • Category 3 Marine Engine Fuel
    The United States and Canada applied to the IMO to establish an emission control area (ECA) along their shorelines. Once the ECA is established, it will trigger international and US EPA sulfur limits in marine fuels:
  • International IMO limits applicable in ECAs are 1% (10,000 ppm) sulfur beginning in 2010, and 0.1% (1,000 ppm) sulfur from 2015. SOx aftertreatment, such as SOx scrubbers, are allowed in lieu of low sulfur fuel.
  • US EPA 2009 EPA Category 3 marine engine rule established a sulfur limit of 1,000 ppm for marine fuels produced and/or sold for use within an ECA. SOx aftertreatment can be used in lieu of low sulfur fuel. Additional flexibilities apply to vessels operated on the Great Lakes and Saint Lawrence Seaway: the low sulfur requirements can be deferred—subject to fuel availability and economic hardship provisions—and are not applicable to steamships.
About D2 and D6 Fuels

D6 is known as Residual Fuel Oil and is of high-viscosity. This particular fuel oil requires pre-heating to 220 – 260 degrees Fahrenheit. D6 si mostly used for generators.

Recent changes in fuel quality regulation now require further refining of the D6 in order to remove the sulfur, which leads to a higher cost. Despite this recent change, D6 is still less useful because of its viscosity as well as that it needs to be pre-heated before it can be used and contains high amounts of pollutants, such as sulfur. Since it requires pre-heating, it cannot be used in small ships, boats or cars. Large ships and power plants can use the residual fuel oil.

D2 is also known as GasOil. It is made from refinery Distillate #2. This type of fuel can be used without additives or reformers. D2 is primarily used as fuel in cars.

Fuel Oils and Diesel Fuels are broken down by numbering system, categorized by API Gravity (weight and viscosity) as well as BTUs.

#1 : #1 fuel oil, kerosene, jet fuel. #1 Diesel, #1 heating oil
#2 : #2 diesel, #2 heating oil
#3 : obselete, no longer used, the ASTM no longer prints the specs for it
#4 : #4 diesel, this is a heavy oil used in some large marine diesels
#5 : #5 fuel oil, also known as bunker oil for ship boilers & diesels
#6 : #6 heavy fuel oil, #3 heavy bunker oil, residuum, for boilers