Definition
Formula for CII:
Where:
D = density at 15°C (kg/m3)
V = kinematic viscosity (cSt)
T =kinematic viscosity temperature (°C)
A CCAI and CII calculator is available on several websites. [3]
The Calculated Ignition Index (CII) is an index of the ignition quality of residual fuel oil. It is used to determine the suitability of heavy fuel oil for (marine) engines.
The effective and efficient running of internal combustion engines is dependent on the ignition quality of the fuel. Incorrect or out of specification fuel can cause problems or severe damage to the engines and associated equipment. [1] The effects may include: corrosion, abrasive wear, clogged cylinder valves, fuel equipment damage, fuel pump failure, premature ignition, ignition failure, explosion, or engine failure. [1]
Several indices are used to characterise fuels. [2] For spark-ignition engines the fuel has an octane rating. For diesel engines it depends on the type of fuel, for distillate fuels the cetane numbers are used. Cetane numbers are tested using a special test engine, however, the existing test engine was not intended for residual fuels. For residual fuel oil two auxiliary indexes have been developed: the Calculated Ignition Index (CII) and Calculated Carbon Aromaticity Index (CCAI). [1]
The calculated ignition index (CII), together with the calculated carbon aromaticity index (CCAI), are empirical indicators which describe the characteristics or properties of a fuel. [1]
Both CII and CCAI are calculated from the density and kinematic viscosity of the fuel. CII was developed by BP to calculate the autoignition capacity of heavy fuel oils (HFO). It is calculated using the measured kinematic viscosity V (cSt or mm2/s) of a given fuel determined at temperature t (°C) and the density ρ15 at 15°C (kg/m3). [1]
Formula for CII:
Where:
D = density at 15°C (kg/m3)
V = kinematic viscosity (cSt)
T =kinematic viscosity temperature (°C)
A CCAI and CII calculator is available on several websites. [3]
CII was designed to produce numbers of the same order as the cetane index number for distillate fuels. The relationship between fuel properties and CII number is shown in the table.
| Description of fuel | CII / Cetane Number |
|---|---|
| Very bad ignition properties | <25 |
| Bad ignition properties | 25 – 28 |
| Acceptable to good ignition properties | 28 – 35 |
| Good ignition properties | 35 – 40 |
| Very good ignition properties | >40 |
CII gives an indication of the quality of heavy fuel oil. Certain practical steps can be taken to ensure the continuing quality. This includes close supervision of fuel, including tests during bunkering using the viscosity data to determine the CII and CCAI. Avoid mixing fuels; checking water content as the water settles out; monitoring the condition and performance of engines. [1]
Diesel fuel, also called diesel oil or historically heavy oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics.
An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating. Octane rating does not relate directly to the power output or the energy content of the fuel per unit mass or volume, but simply indicates gasoline's capability against compression.
Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats.
Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, detergents, dispersants, and, for multi-grade oils, viscosity index improvers. The main function of motor oil is to reduce friction and wear on moving parts and to clean the engine from sludge and varnish (detergents). It also neutralizes acids that originate from fuel and from oxidation of the lubricant (detergents), improves the sealing of piston rings, and cools the engine by carrying heat away from moving parts.
RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (H2), but is cheaper, is stable at room temperature, and presents a lower explosion hazard. RP-1 is far denser than H2, giving it a higher energy density (though its specific energy is lower). RP-1 also has a fraction of the toxicity and carcinogenic hazards of hydrazine, another room-temperature liquid fuel.
Fuel oil is any of various fractions obtained from the distillation of petroleum. Such oils include distillates and residues. Fuel oils include heavy fuel oil, marine fuel oil (MFO), furnace oil (FO), gas oil (gasoil), heating oils, diesel fuel, and others.
Starting fluid is a volatile, flammable liquid which is used to aid the starting of internal combustion engines, especially during cold weather or in engines that are difficult to start using conventional starting procedures. It is typically available in an aerosol spray can, and may sometimes be used for starting direct injected diesel engines or lean burn spark engines running on alcohol fuel. Some modern starting fluid products contain mostly volatile hydrocarbons such as heptane, with a small portion of diethyl ether, and carbon dioxide. Some formulations contain butane or propane as both propellant and starting fuel. Historically, diethyl ether, with a small amount of oil, a trace amount of a stabilizer and a hydrocarbon propellant has been used to help start internal combustion engines because of its low 160 °C (320 °F) autoignition temperature.
Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable instead of the fluid. Most liquid fuels in widespread use are derived from fossil fuels; however, there are several types, such as hydrogen fuel, ethanol, and biodiesel, which are also categorized as a liquid fuel. Many liquid fuels play a primary role in transportation and the economy.
Cetane number is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It plays a similar role for diesel as octane rating does for gasoline. The CN is an important factor in determining the quality of diesel fuel, but not the only one; other measurements of diesel fuel's quality include energy content, density, lubricity, cold-flow properties and sulphur content.
A visbreaker is a processing unit in an oil refinery whose purpose is to reduce the quantity of residual oil produced in the distillation of crude oil and to increase the yield of more valuable middle distillates by the refinery. A visbreaker thermally cracks large hydrocarbon molecules in the oil by heating in a furnace to reduce its viscosity and to produce small quantities of light hydrocarbons.. The process name of "visbreaker" refers to the fact that the process reduces the viscosity of the residual oil. The process is non-catalytic.
The viscosity index (VI) is an arbitrary, unit-less measure of a fluid's change in viscosity relative to temperature change. It is mostly used to characterize the viscosity-temperature behavior of lubricating oils. The lower the VI, the more the viscosity is affected by changes in temperature. The higher the VI, the more stable the viscosity remains over some temperature range. The VI was originally measured on a scale from 0 to 100; however, advancements in lubrication science have led to the development of oils with much higher VIs.
Vegetable oil can be used as an alternative fuel in diesel engines and in heating oil burners. When vegetable oil is used directly as a fuel, in either modified or unmodified equipment, it is referred to as straight vegetable oil (SVO) or pure plant oil (PPO). Conventional diesel engines can be modified to help ensure that the viscosity of the vegetable oil is low enough to allow proper atomization of the fuel. This prevents incomplete combustion, which would damage the engine by causing a build-up of carbon. Straight vegetable oil can also be blended with conventional diesel or processed into biodiesel, HVO or bioliquids for use under a wider range of conditions.
The calculated carbon aromaticity index (CCAI) is an index of the ignition quality of residual fuel oil.
Cetane index is used as a substitute for the cetane number of diesel fuel. The cetane index is calculated based on the fuel's density and distillation range. There are two methods used, ASTM D976 and D4737. The older D976, or "two-variable equation" is outdated and should no longer be used for cetane number estimation. It is, however, still required by the United States Environmental Protection Agency (EPA) as an alternative method for satisfying its aromaticity requirement for diesel fuel. D4737 is the newest method and is sometimes referred to as "the four-variable equation". D4737 is the same method as ISO 4264. Cetane index in some crude oil assays is often referred to as Cetane calcule, while the cetane number is referred to as Cetane measure.
Crude oil is extracted from the bedrock before being processed in several stages, removing natural contaminants and undesirable hydrocarbons. This separation process produces mineral oil, which can in turn be denoted as paraffinic, naphthenic or aromatic. The differences between these different types of oils are not clear-cut, but mainly depend on the predominant hydrocarbon types in the oil. Paraffinic oil, for example, contains primarily higher alkanes, whereas naphthenic oils have a high share of cyclic alkanes in the mixture.
Automotive oil recycling involves the recycling of used oils and the creation of new products from the recycled oils, and includes the recycling of motor oil and hydraulic oil. Oil recycling also benefits the environment: increased opportunities for consumers to recycle oil lessens the likelihood of used oil being dumped on lands and in waterways. For example, one gallon of motor oil dumped into waterways has the potential to pollute one million gallons of water.
CCAI is an acronym that can refer to:
Base oils are used to manufacture products including lubricating greases, motor oil and metal processing fluids. Different products require different compositions and properties in the oil. One of the most important factors is the liquid’s viscosity at various temperatures. Whether or not a crude oil is suitable to be made into a base oil is determined by the concentration of base oil molecules as well as how easily these can be extracted.
A cetane improver [′sē‚tān im′prüv·ər] is a chemical which has the effect of increasing a diesel fuel's cetane number. A few examples are nitrates, nitroalkanes, nitrocarbonates and peroxides.
Heavy fuel oil (HFO) is a category of fuel oils of a tar-like consistency. Also known as bunker fuel, or residual fuel oil, HFO is the result or remnant from the distillation and cracking process of petroleum. For this reason, HFO is contaminated with several different compounds including aromatics, sulfur, and nitrogen, making emissions upon combustion more polluting compared to other fuel oils. HFO is predominantly used as a fuel source for marine vessel propulsion using marine diesel engines due to its relatively low cost compared to cleaner fuel sources such as distillates. The use and carriage of HFO on-board vessels presents several environmental concerns, namely the risk of oil spill and the emission of toxic compounds and particulates including black carbon. The use of HFOs is banned as a fuel source for ships travelling in the Antarctic as part of the International Maritime Organization's (IMO) International Code for Ships Operating in Polar Waters (Polar Code). For similar reasons, an HFO ban in Arctic waters is currently being considered.