Diesel fuel is any fuel used in diesel engines. Chemical composition and cetane number. Boiling point and freezing point of representative diesel fuel hydrocarbons. Disadvantages of Diesel Fuel. Environment hazards of sulfur. Fuel value and price.
Краткое сожержание материала:

Размещено на

Ministry of Education and Science of Ukraine

National Aviation University

Chemmotology Department

Individual work

On topic: “Diesel fuels”

Created by

Student of 206 group FLA

Novak Sergey

Kiev 2009

Contents

• Diesel fuel
• Chemical composition
• Boiling point and freezing point of representative diesel fuel hydrocarbons
• Cetane Number
• Reduction of sulfur emissions
• Refining
• Petroleum diesel
• Diesel engine
• Disadvantages of Diesel Fuel
• Environment hazards of sulfur
• Road hazard
• Synthetic diesel
• Biodiesel
• Transportation
• Use as car fuel
• Railroad
• Aircraft
• Other uses
• Fuel value and price
• Reference

Diesel fuel

Diesel fuel in general is any fuel used in diesel engines. The most common is a specific fractional distillate of petroleum fuel oil, but alternatives that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel, are increasingly being developed and adopted. To distinguish these types, petroleum-derived diesel is increasingly called petrodiesel. Ultra-low sulfur diesel (ULSD) is a standard for defining diesel fuel with substantially lowered sulfur contents. As of 2007, almost every diesel fuel available in America and Europe is the ULSD type. In the UK, diesel is commonly abbreviated DERV, standing for Diesel Engined Road Vehicle (fuel).

Chemical composition

Petroleum-derived diesel is composed of about 75% saturated hydrocarbons (primarily paraffins including n, iso, and cycloparaffins), and 25% aromatic hydrocarbons (including naphthalenes and alkylbenzenes). The average chemical formula for common diesel fuel is C12H23, ranging approximately from C10H20 to C15H28.

Diesel fuel is a very complex mixture of thousands of individual compounds, most with carbon numbers between 10 and 22. Most of these compounds are members of the paraffinic, naphthenic, or aromatic class of hydrocarbons; each class has different chemical and physical properties. Different relative proportions of the three classes is one of the factors that make one diesel fuel different from another. The following discussion explains how properties of the three classes influence the properties of the whole fuel and affect its performance in a diesel engine.

diesel fuel chemical composition

Boiling point and freezing point of representative diesel fuel hydrocarbons

Boiling Points

For compounds in the same class, boiling point increases with carbon number. Forcompounds of the same carbon number, the order of increasing boiling point by class is isoparaffin, n-paraffin, naphthene, and aromatic. The boiling point difference (60° to80°C or 100° to 150°F) between isoparaffins and aromatics of the same carbon number is larger than the boiling point difference (about 20°C or 35°F) between compounds of the same class that differ by one carbon number. Thus, the compounds that boil at about 260°C (500°F), the middle of the diesel fuel boiling range, might be C12 aromatics, C13 naphthenes, C14 n-paraffin, and C15 isoparaffins.

Freezing Point

Freezing points (melting points) also increase with molecular weight, but they are strongly influenced by molecular shape. Molecules that fit more easily into a crystal structure have higher freezing points than other molecules. This explains the high melting points of n-paraffins and unsubstituted aromatics, compared to the melting points of isoparaffins and naphthenes of the same carbon number.

Compound Chemical Hydrocarbon Boiling Freezing Formula Class Point, °C/°F Point, ЦC/°F

Naphthalene	C10H8	Aromatic	218/424	80/176
Tetralin	C10H12	Aromatic	208/406	-35/-31
cis-Decalin	C10H18	Naphthene	196/385	-43/-45
1,3-Diethylbenzene	C10H14	Aromatic	181/358	-84/-119
n-Butylcyclohexane	C10H20	Naphthene	181/358	-75/-103
n-Pentylcyclopentane	C10H20	Naphthene	181/358	-83/-117
Decane	C10H22	n-Paraffin	174/345	-30/-22
Anthracene	C14H10	Aromatic	341/646	215/419
1-Pentylnaphthalene	C15H18	Aromatic	306/583	-24/-11
n-Nonylcyclohexane	C15H30	Naphthene	282/540	-10/14
n-Decylcyclopentane	C15H30	Naphthene	279/534	-22/-8
n-Pentadecane	C15H32	n-Paraffin	271/520	10/50
2-Methyltetradecane	C15H32	Isoparaffin	265/509	-8/18
1-Decylnaphthalene	C20H28	Aromatic	379/714	15/59
n-Tetradecylbenzene	C20H34	Aromatic	354/669	16/61
n-Tetradecylcyclohexane	C20H40	Naphthene	354/669	25/77
n-Pentadecylcyclopentane	C20H40	Naphthene	353/667	17/63
Eicosane	C20H42	n-Paraffin	344/651	36/97
2-Methylnonadecane	C20H42	Isoparaffin	339/642	18/64

Density

Table lists density and heat of combustion (heating value) for some representative diesel fuel hydrocarbons. For compounds of the same class, density increases with carbon number. For compounds with the same carbon number, the order of increasing density is paraffin, naphthene, and aromatic.

Net Heat of Net Heat of Hy...