Three phase is a system produced by a generator consisting of three sources having the same
amplitude and frequency but out of phase with each other by 120.
The generation of electricity is either done by a power station or from renewable energy
13.36 A fuel oil having an analysis on a mass basis of 85.7%
' C, 14.2% H. 0.1% inert matter burns with air to give products
with a dry molar analysis of 12.29% C02, 3.76% 02, 83.95%
N2. Determine the airfuel ratio on a mass basis
13.33 Decane (C10H22) bums completely in dry air. The air-fuel ratio on a mass basis is 33 kg.
(3) analysis of the products on a dry molar basis.
(b) percent of theoretical air.
KNOWN: Decane burns completely in air with known air-fuel rat
Liquid octane (Carls) at 25C. 1 atm enters the
combustor of a simple open gas turbine power plant and
burns completely with 400% of theoretical air entering the
compressor at 25C. 1 atm. Products of combustion exit
the turbine at 627C, 1 atm. The rate o
known t he me ewkws a~wmlaus+m chamber with km Wm MAJ
Peas u. M a. swan. molcw ow mic, ohm H- bum
in; "Dmrmine -Hne heed WW we cfw_or am of 41m: GXH' kwmvas.
av MG 5' D 3
m 3.76 main 0% 1. act. as? and;
C 8 mole 0+ Duh-Mm Mr. (2) ho. tie
Problem 13.50 (Continued) Page 2
N: 2(3.76)(12.5)(1.20) = 2d a d = 56.4
The balanced chemical equation for combustion with 120% theoretical air is
Cngg + 15(02 + 3.76N2) * 8C0: + 9H20 + 2.502 + 56.4N2
The energy rate balance reduces with assumptions 1-3 t
PROBLEM 13. H
A coal sample has a mass analysis of 804% carbon.
3.9% hydrogen (Hz), 5.0% oxygen (02). 11% nitrogen (N2).
1.1% sulfur. and the rest is noncombustible ash. For complete
combustion with 120% of the theoretical amount of air,
determine (a) t
Problem 12.104 (Continued) ~ Page 2
The mass flow rate of the entering atmospheric air is #21 = n':_ + r51 or
#11 7 ma (1 + (91)
The rate liquid evaporates into the moist air stream is
(rate liquid evaporates): mg my, 2 Iii, (03 H a), )
From Eqs. (1), (2)
P1.107 liquid water enters a cooling tower operating at steady state at 40C with a mass flow
rate of 10 kg/h. Cooled water at 25C exits the cooling tower at the same mass ow rate.
Makeup water is supplied at 23C. Atmospheric air enters the tower at 30C, 1
13.29 Octane (CsHis) is burned 20% excess air, yielding C02, C0, 02, H20, and NZ only. If 5%
of the dry products (molar basis) is 02, determine
(a) the balanced reaction equation.
(b) the analysis of the products on a dry molar basis.
KNOWN: 0ng3 is bur
Problem 12.98 (Continued) - Page 2
(1) Each of the control volumes shown in the accompanying gure is at steady state with
and negligible effects of kinetic and potential energy.
(2) The water vapor entering is saturated vapor in option
ERQLEH '1 be
Plot the enthalpy of combustion for gaseous propane
(Cal-1.). in Btu per lbmol of fuel, at 1 atm versus temperature '
in the interval 77 to 500F. Assume water vapor in the
products. For propane, let c, = 0.41 Btu/lb - R.
C; 8 fen-h uwlehk' wH
Problem 13.42 (Continued) - Page 2
H: 5+ 1 =2cic=3
N: 2(3.76)a = 2d = 2(3.76)(3) -> d = 11.28
The balanced chemical equation for complete combustion of the fuel with theoretical air is
CH30H + 3(02 + 3.76N2) 2C0; + 3H20 + 11.28N2
PROBLEM l3. L8
KNQDN: 241410 burns cowpkklj 3+ [50% 9f +More11a4 41;. TIM.
Wuch Combumfo m (a l
20 51-1., Gob'c H a 24 '6 429M11P+NTMlg1Lu1J
IND Piaf m cudova" 6 Lugkv Vror WildaLtd ) k. CHI-cl pt? 5
dew pom!- the?
(@4th: If 5
In m in? NW"
13.20 A gaseous fuel mixture with a molar analysis of 70% CH4, 10% H2, 12% N2, 3% 02, and
5% C02 burns completely with moist air to form gaseous products at 1 atm consisting of C02,
H20, and N2 only The humidity ratio of the moist air is 0. 01 kg Hzolkg d
Problem 13.57 (Continued) Page 3
UR = (ifs )C1H5 _ SETR
With enthalpy of formation value for Csz from Table A-25
U = an IC H 84,680 - 5km] 8.314 298K
R ( 0 2 6cfw_ momzs) ( oi kmovi )
UR = 97,068 kJ
Similarly for the products
UP = [2079)02 +3(E;)H