Automotive Diesel Oil and Heating Oil Flashcards
(39 cards)
In France, what is the sulfur spec for HHO ?
1000 ppm
What is the problem with n-paraffins in Diesel ?
Very good combustion properties but low resistance to low temperatures
In N-paraffins, what is the link between carbon chain lenght and cristallization temperature ?
The longer the chain, the higher the cristallization temperature = the worst the resistance to low temperatures
What are the three measurements used to characterize a diesel cold flow properties ?
- Cloud point
- Cold Filter Plugging Point (CFPP)
- Pour point (not for ADO anymore)
What is the cloud point ?
The temperature at which a cloud appears in the test tube
What is the pour point ?
The temperature at which the product can no longer flow if the test tube is tilted for 5s
What are the cloud point specs for ADO ?
From October to March : -5°C
From April to September : +5°C
What are the specification for cloud and pour point of HHO ?
- Cloud Point : +2°C
- Pour Point : -9°C
What are the specs for CFPP for ADO?
From October to March : -15°C
From Qpril to September : 0°C
How can we improve cold flow properties of ADO ?
- change formulation (incorporate lighter HC like kerosene cut, nahthenes or aromatics) but negative effect on comubstion quality
- Additives like anti-settling additives (WASA)
What is the cetane number ?
The cetane number measure the ability of ADO or HHO to auto-ignite. The higher the cetane number, the shorter the ignition delay
Which family of components has the best cetane number ?
N-paraffins have a good cetane number
How is the cetane number measured ?
Cetane number is measure with a Diesel CFR engine and comparison with 2 references
What are the two references to measure cetane number ?
Good reference : nC16
Bad reference : hepta-methylnonane
How is the calculated cetane number estimated ?
Volatility (ASTM distillation) and chemical composition (density) are taken into account
What are the specifications for cetane number ?
- ADO : measured = 51 and calculated = 46
- HHO : measured = 40
Why are measured and calculated cetane number sometimes very different?
Because of the additives added in small quantities : measured effect on the CFR engine but too small quantities to impact calculated value
What are the ASTM distillation specs for ADO ?
- max 65% distilled at 250°C
- max 85% distilled at 350°C
- max 360 °C at 95% distilled
What is the spec for density of ADO ?
820 < d < 845 kg/m3 at 15°C
What is the spec for viscosity of ADO ?
2 < viscosity < 4.5 cSt at 40°C
Why are nitrogen impurities a problem for ADO ?
Some nitrogen compounds are gum precursors
Why is water a problem in ADO ?
It can damage the injection pump and the injectors and to reduce the risk of bacterial contamination
What is the spec for water content in ADO ?
200 mg/kg
What new problem arrived with low sulfur content in ADO ?
Low sulfur content means poor lubricating power of ADO
