Fuels in Transportation - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 12

Chapter 2
Fuels in Transportation

In 1900 there were no gas stations—blacksmiths and pharmacists sold the fuel.
People first used petrol for lighting and later to lubricate machine tools. At the end
of the 19th century, boilers in factories and in ships began to use oil instead of coal
[ 1 ]. Since this time the consumption of oil, coal and natural gas has been con-
tinuously growing.
Figure 2.1 presents the development of fossil fuel consumption and CO 2
emissions [ 2 ].

2.1 Classification of Types of Fuels

There is an increasing variety of fuels, which are presented in Fig. 2.2 .
The heating value of liquid fuels is relatively equal per mass unit. It is about 11.0-
12.0 kWh kg -1 (17,017-18,564 BTU lb -1 ), which is equal on average to 39,574-
43,172 kJ kg -1 . Gasoline has a volume-specific heating value of 8.8 kWh l -1
(113,660 BTU gal -1 (US) or 136,512 BTU gal -1 (UK)), i.e., 31,680 kJ l -1 at a
density of 0.762. Diesel fuel has a volume-specific heating value of 10.0 kWh l -1
(129,163 BTU gal -1 (US)), i.e., 36,000 kJ l -1 , because of its higher density

(0.835) [ 3 ].
Components of alternative fuels containing oxygen, such as biological ethanol
(29,700 kJ kg -1 , i.e., 12,771 BTU lb -1 or 155,132 BTU gal -1 (UK), ether, and
fatty acid methyl ester have less heating value than pure hydrocarbons, since the
oxygen bound in the molecule does not take part in the burning. Kerosene has a
mass-specific heating value of 38,000 kJ kg -1 , i.e., 16,340 BTU lb -1 , and heavy
fuel oil approximately 41,200 kJ kg -1 or 17,716 BTU lb -1 . The density of ker-
osene is similar to diesel fuel. Heavy fuel oil has a higher density, depending on
the quality [ 4 ].