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Fuels and Combustion

December 8, 2016
Published By : Pratik Kataria
Categorised in:

$G.C.V = N.C.V + ({9 . h. \text"latent heat of water"}/{100})$
GCV = Gross Calorific Value

NCV = Net Calorific Value
h = percentage of hydrogen in fuel


$G.C.V. = L = {(W+w) (t_2 – t_1)}/{x}$ cal/gm

x = mass of fuel in gm

W = mass of water in calorimeter

w = water equivalent of calorimeter set

L = Gross calorific value of fuel
$(t_2 – t_1)$ = Rise in temperature of water


NCV = GCV – 0.09 x h x 587 cal/gm

$\text"GCV of coal" = {(W+w) (t_2 – t_1 + t_c) – (a+f)}/{m}$
f = Fuse wire correction
a = Acid correction (a)
$t_c$ = Cooling correction

m = weight

$NCV = {W(t_2 – t_1)}/{V} – {m * 587}/{V}$ kcal/$m^3$
Heat = $m/V$ x 587 kcal/$m^3$

NCV = GCV – $m/V$ x 587

$C% = {\text"Weight of " CO_2 * 12 * 100}/{\text"Weight of coal sample" * 44}$

$H% = {\text"Weight of " HO_2 \text"formed" * 2 * 100}/{\text"Weight of coal sample" * 18}$

$Moisture% = {\text"Weight of moisture"}/{\text"Weight of coal"}$ x 100

$Ash% = {\text"Weight of ash"}/{\text"Weight of coal"}$ x 100

Fixed carbon (F.C.) = 100 – (moisture% + V.M% + ash%)

Sulphar in coal (S%) = ${32}/{233}$ x ${\text"Weight of "BaSO_4}/{\text"Weight of coal"}$ x 100

Volatile matter (V.M) = ${\text"Weight of V.M"}/{\text"Weight of coal"}$ x 100

$N% = {\text"Volume of acid consumed x normality of acid x 1.4"}/{\text"Weight of coal"}$


Solid or liquid fuels

$O_2$ quantity = $({32}/{12}C + 8H +S – O)$ kg of oxygen

Actual Air quantity = ${\text"Oxygen quantity" * (100 + %excess air) }/{23}$ kg

moles of an element in fuel = ${\text"Weight of element in fuel"}/{\text"Atomic weight of element"}$

Gaseous fuels

$O_2$ volume required = $m^3$ of the gas component x Volumes of $O_2$ per volume of gas

Actual air volume required = ${\text"Volume of oxygen" * (100 + %\text"excess air")}/{21}$