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Heptane or n-heptane is the straight-chain alkane with the chemical formula H 3 C(CH 2) 5 CH 3 or C 7 H 16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 point is 100% iso-octane ).
All alkanes react with oxygen in a combustion reaction, although they become increasingly difficult to ignite as the number of carbon atoms increases. The general equation for complete combustion is: C n H 2n+2 + ( 3 / 2 n + 1 / 2 ) O 2 → (n + 1) H 2 O + n CO 2 or C n H 2n+2 + ( 3n + 1 / 2 ) O 2 → (n + 1) H 2 O + n CO 2
Since the heat of combustion of these elements is known, the heating value can be calculated using Dulong's Formula: HHV [kJ/g]= 33.87m C + 122.3(m H - m O ÷ 8) + 9.4m S where m C , m H , m O , m N , and m S are the contents of carbon, hydrogen, oxygen, nitrogen, and sulfur on any (wet, dry or ash free) basis, respectively.
A complete set of equations for the combustion of a hydrocarbon in the air, therefore, requires an additional calculation for the distribution of oxygen between the carbon and hydrogen in the fuel. The amount of air required for complete combustion is known as the "theoretical air" or "stoichiometric air". [3]
The constant volume adiabatic flame temperature is the temperature that results from a complete combustion process that occurs without any work, heat transfer or changes in kinetic or potential energy. Its temperature is higher than in the constant pressure process because no energy is utilized to change the volume of the system (i.e., generate ...
Quantity (common name/s) (Common) symbol/s Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer
The formula for acyclic saturated hydrocarbons (i.e., alkanes) is C n H 2n+2. [1]: 623 The most general form of saturated hydrocarbons, (whether linear or branched species, and whether with or without one or more rings) is C n H 2n+2(1-r), where r is the number of rings. Those with exactly one ring are the cycloalkanes.
Nonane undergoes combustion reactions that are similar to other alkanes. In the presence of sufficient oxygen, nonane burns to form water and carbon dioxide. C 9 H 20 + 14O 2 → 9CO 2 + 10H 2 O. When insufficient oxygen is available for complete combustion, the burning products include carbon monoxide. 2C 9 H 20 + 19O 2 → 18CO + 20H 2 O