Cement Kilns

Air Composition Data


Although there have been occasional experiments with oxygen enrichment in special circumstances such as white cement manufacture, the heat used in the cement industry has always been produced by burning fuels in air. The large amount of inert material (mainly nitrogen) in air affects the efficiency of the process by inflating the thermal mass of the exhaust gases produced. The following data are supplied to perform standard calculations on the efficiency of systems, including the derivation of thermodynamic functions.


Standard Air: data for 20°C

Dry Air 50% Humidity @ 20°C
%v/v %m/m %v/v %m/m
N2 78.078730 75.506792 77.386302 75.085820
O2 20.944586 23.142107 20.758842 23.013083
Ar 0.933937 1.288226 0.925655 1.281044
H2O 0.000000 0.000000 0.886833 0.557529
CO2 0.040000 0.060996 0.039645 0.060656
Ne 0.001818 0.001265 0.001802 0.001258
He 0.000524 0.000072 0.000519 0.000072
CH4 0.000180 0.000100 0.000178 0.000099
Kr 0.000114 0.000330 0.000113 0.000328
H2 0.000055 0.000004 0.000055 0.000004
N2O 0.000030 0.000046 0.000030 0.000046
CO 0.000010 0.000010 0.000010 0.000010
Xe 0.000009 0.000041 0.000009 0.000041
O3 0.000007 0.000012 0.000007 0.000012

Air after removal of oxygen by combustion: data for 20°C

Dry Air 50% Humidity @ 20°C
%v/v %m/m %v/v %m/m
N2 98.764558 98.242079 97.659227 97.530622
O2 0.000000 0.000000 0.000000 0.000000
Ar 1.181370 1.676115 1.168149 1.663977
H2O 0.000000 0.000000 1.119157 0.724187
CO2 0.050597 0.079362 0.050031 0.078787
Ne 0.002300 0.001646 0.002274 0.001634
He 0.000663 0.000094 0.000655 0.000093
CH4 0.000228 0.000130 0.000225 0.000129
Kr 0.000144 0.000430 0.000143 0.000427
H2 0.000070 0.000005 0.000069 0.000005
N2O 0.000038 0.000060 0.000038 0.000059
CO 0.000013 0.000013 0.000013 0.000012
Xe 0.000011 0.000053 0.000011 0.000053
O3 0.000009 0.000015 0.000009 0.000015

© Dylan Moore 2011: last edit 23/05/13.