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The flames caused as a result of a fuel undergoing combustion (burning) Air pollution abatement equipment provides combustion control for industrial processes.. Combustion, or burning, [1] is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.
A particularly important class of exothermic reactions is combustion of a hydrocarbon fuel, e.g. the burning of natural gas: CH 4 + 2O 2 → CO 2 + 2H 2 O ΔH⚬ = - 890 kJ/mol Video of an exothermic reaction. Ethanol vapor is ignited inside a bottle, causing combustion. These sample reactions are strongly exothermic.
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
Infinitely fast chemical reaction is assumed with oxidants reacting in stoichiometric proportions to form products. SCRS considers the reaction to be irreversible i.e. rate of reverse reaction is presumed to be very low. [2] 1 kg of fuel + s kg of oxidant → (1 + s) kg of products For the combustion of the methane gas the equation becomes
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.
Another example of a double displacement reaction is the reaction of lead(II) nitrate with potassium iodide to form lead(II) iodide and potassium nitrate: + + Forward and backward reactions According to Le Chatelier's Principle , reactions may proceed in the forward or reverse direction until they end or reach equilibrium .
Hence even the simplest combustion reaction involves very tedious and rigorous calculation if all the intermediate steps of the combustion process, all transport equations and all flow equations have to be satisfied simultaneously. All these factors will have a significant effect on the computational speed and time of the simulation.
Some multistep reactions can also have apparent negative activation energies. For example, the overall rate constant k for a two-step reaction A ⇌ B, B → C is given by k = k 2 K 1, where k 2 is the rate constant of the rate-limiting slow second step and K 1 is the equilibrium constant of the rapid