Cetane Index Estimation
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ScribdTranslationsCetane Index Estimation
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ScribdTranslationsAmar Telidji University Laghouat.
Department of Process Engineering
Module: MPC 131
TP N°4: Estimation of the cetane index
The procedure for determining the cetane index on CFR engine is not
extremely widespread, given its complexity and the cost of its implementation.
There are also several methods to estimate the cetane index of the
diesels based on their physical characteristics or chemical structure.
The most well-known formula was developed by the company Ethyl (ASTM D 976) and
is expressed as follows:
CCI = 454.74 - 1641.416 ρ + 774.74 ρ2- 0.554 (T50) + 97,083 (log T50)2 (1)
With:
CCI: calculated cetane index
ρ: density at 15 °C in kg/l
T50Temperature (°C) corresponding to 50% distilled according to ASTM D 86 method.
The discrepancies between the measured and calculated cetane indices according to the above formula,
are relatively low within a cetane index range between 40 and 55.
However, for diesel fuels containing a pro-cetane additive, the CCI will obviously be
much lower than the real value.
- Perform the distillation of diesel and determine the value of T50.
- Measure the density and deduce ρ (the density at 15 °C in kg/l).
- Calculate the cetane index value (CCI) according to relation (1).
- Commenter.