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Fuels and Combustion

The document contains a series of calculations related to fuels and combustion, including specific gravity, density, higher heating values, and air-fuel ratios for various fuels and coal compositions. It presents problems requiring the application of chemical formulas and combustion principles. The calculations involve different types of fuels such as liquid dodecane, bituminous coal, and octane.

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Christian Robles
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41 views13 pages

Fuels and Combustion

The document contains a series of calculations related to fuels and combustion, including specific gravity, density, higher heating values, and air-fuel ratios for various fuels and coal compositions. It presents problems requiring the application of chemical formulas and combustion principles. The calculations involve different types of fuels such as liquid dodecane, bituminous coal, and octane.

Uploaded by

Christian Robles
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Tuesday, April 27, 2021 10:32 PM

Fuels and Combustion Page 1


Fuels and Combustion Page 2
Tuesday, April 27, 2021 10:37 PM

A certain liquid fuel at 28°API is used for


combustion operation, wherein the
temperature reading of the fuel before
combustion is 29°C. Answer the ff:
a. What will be the specific gravity of fuel
oil?
b. What is the density of fuel oil?

Fuels and Combustion Page 3


Calculate the higher heating value of liquid
dodecane fuel. The chemical formula of
dodecane is C12H26.
Wednesday, April 28, 2021 5:06 AM

Fuels and Combustion Page 4


The ultimate analysis of coal is given by
below:
C = 68.5%
H = 2.5%
O = 3.5%
S = 1.5%
Ash = 12%

Calculate the higher heating value,


Wednesday, April 28, 2021 5:16 AM

Fuels and Combustion Page 5


Fuel in oil day tank for use of an industrial
boiler is tested with hydrometer. The
hydrometer reading indicated a SG=0.924
when the temperature of the oil in the tank
is 35C. Calculate the higher heating value.
Wednesday, April 28, 2021 5:17 AM

Fuels and Combustion Page 6


A bituminous coal has the ff. compositions
C = 71.5%
H = 5.0 %
O = 7.0 %
N = 1.3 %
S = 3.6 %
Ash = 8.2%
W = 3.4%

Calculate for complete combustion


theoretical weight of air required in
kgair/kgcoal.
Wednesday, April 28, 2021 5:22 AM

Fuels and Combustion Page 7


Liquid Octane (C8H18) fuel is burned with
ideal proportion of air. Calculate the ideal
air-fuel ratio by weight,
Wednesday, April 28, 2021 5:31 AM

Fuels and Combustion Page 8


A typical industrial fuel oil, C16H32 with 20%
excess air by weight. Assuming complete
oxidatuin of the fuel, calculate the actual air-
fuel ratio by weight.
Wednesday, April 28, 2021 5:25 AM

Fuels and Combustion Page 9


Calculate the minimum volume of day tank
of 28API fuel having a fuel consumption of
1kg/s
Wednesday, April 28, 2021 5:36 AM

Fuels and Combustion Page 10


It is required to find the theoretical volume
of air at 20C and 100kPa absolute pressure
to burn one kg of Franklin County coal. The
ultimate analysis of coal as fired is as
follows:

C = 65.65%
H = 5.87 %
O = 18.61 %
S = 1.51 %
Ash = 5.36%
W = 3%
Wednesday, April 28, 2021 5:41 AM

Fuels and Combustion Page 11


There are 20kg of flue gas formed per kg of
fuel oil burned in the combustion of a fuel
oil C12H26. What is the excess air in
percent?
Wednesday, April 28, 2021 5:47 AM

Fuels and Combustion Page 12


In the theoretical air-fuel ratio is 15, what is
the approximate higher heating value in
kJ/kgfuel?
Wednesday, April 28, 2021 5:48 AM

Fuels and Combustion Page 13

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