30-03-2012, 03:42 PM
DIESEL FUEL
DIESEL FUEL.ppt (Size: 350.5 KB / Downloads: 98)
Use of Diesel Fuel
Trucks
Locomotives
And now passenger cars
Ships
Stationary Applications
Power generation
Pump sets in agriculture
Refinery Capacity
Increased consumption of diesel fuel will increase crude oil consumption because diesel oil density is more.
Refinery energy consumption decreases slightly as diesel production increases (according to one estimate).
But to cater to increased diesel production, existing facilities must be expanded and will increase costs (so lower diesel cost benefit will be lost).
But there could be a reduced crude oil usage with increased diesel production.
Properties of diesel fuel
It is found that
Specific gravity, flash point, viscosity, sulfur content, and carbon residue increase with increase in service severity.
The cetane number (which measures the fuel’s ignition quality) decreases with increase in service severity. There is also a decrease in volatility with increase in service severity.
Properties are, however, inter-related and it is difficult to isolate the effect of any single variable
Aniline Point
This is an approximate measure of the aromatic content of a hydrocarbon fuel.
It is defined as the lowest temperature at which a fuel oil is completely miscible with an equal volume of aniline.
Aniline is an aromatic compound and aromatics are more miscible in aniline than are paraffins.
Hence, the lower the aniline point, the higher the aromatics content in the fuel oil.
The higher the aromatics content, the lower the cetane number of the fuel.
The aniline point can thus be used to indicate the probable ignition behavior of a diesel fuel.
Cetane Improvers
These are compounds that readily decompose to give free radicals and thus enhance the rate of chain initiation in diesel combustion.
They promote fast oxidation of fuels and thus improve their ignition characteristics.
Chemical compounds such as alkyl nitrates, ether nitrates, dinitrates of polyethylene glycols and certain peroxides are well known cetane improvers.
In general, however, in view of their low cost and ease of handling, most commercial significance has been attached to different primary alkyl nitrates.