Flue Gas Analysis Table
Impact on Efficiency
The most common measurement for the purposes of efficiency are oxygen (O) or carbon-dioxide (CO2) and temperature. For a given fuel type, it is possible to calculate the percent O if CO2 is measured, or to calculate CO2 if O is measured. Another common indicator is CO; if O is high, there won't be any significant CO. Measurable CO means the unit is starved for O or there is something very wrong with the flame. The O and/or CO2 measurement along with the temperature of the flue gas and the combustion air temperature, are the needed variables to determine combustion efficiency.
Operation
Using a Flue Gas Analyzer or any meter designed to measure oxygen or carbon-monoxide, and taking the flue gas temperature and the temperature of the combustion air, the following Table can be used to determine combustion efficiency when operating on natural gas. The Temperature Column is the NET Difference between Flue Gas and Combustion Air Temperatures.(Flue Gas Temp -minus- Combustion Air Temp)Note that each fuel has its own characteristics. Therefore, these numbers are valid ONLY for natural gas.Read Combustion Efficiency in the Column under the NET Temperature Difference, in the row for the measured O2% or CO2%.
Excess
Air %
|
Excess
O2 %
|
Excess
CO2 %
|
Combustion Efficiency at Net Temperature Difference
|
||||||||
170F
|
220F
|
270F
|
330F
|
380F
|
430F
|
480F
|
530F
|
580F
|
|||
0.0
|
0.0
|
11.8
|
86.3
|
85.3
|
84.2
|
83.0
|
81.9
|
80.8
|
79.7
|
78.6
|
77.5
|
4.5
|
1.0
|
11.2
|
86.2
|
85.1
|
84.0
|
82.7
|
81.6
|
80.5
|
79.3
|
78.2
|
77.0
|
9.5
|
2.0
|
10.7
|
86.1
|
84.9
|
83.8
|
82.4
|
81.2
|
80.1
|
78.9
|
77.7
|
76.5
|
15.0
|
3.0
|
10.1
|
85.9
|
84.7
|
83.5
|
82.1
|
80.9
|
79.7
|
78.4
|
77.2
|
75.9
|
21.1
|
4.0
|
9.6
|
85.7
|
84.5
|
83.2
|
81.7
|
80.5
|
79.2
|
77.9
|
76.6
|
75.3
|
28.1
|
5.0
|
9.0
|
85.5
|
84.2
|
82.9
|
81.3
|
80.0
|
78.6
|
77.3
|
75.9
|
74.5
|
35.9
|
6.0
|
8.4
|
85.3
|
83.9
|
82.5
|
80.9
|
79.5
|
78.0
|
76.6
|
75.2
|
73.7
|
44.9
|
7.0
|
7.9
|
85.0
|
83.5
|
82.1
|
80.3
|
78.8
|
77.3
|
75.8
|
74.3
|
72.8
|
55.3
|
8.0
|
7.3
|
84.7
|
83.1
|
81.6
|
79.7
|
78.1
|
76.6
|
74.9
|
73.3
|
71.7
|
67.3
|
9.0
|
6.7
|
84.3
|
82.7
|
81.0
|
79.0
|
77.3
|
75.6
|
73.9
|
72.2
|
70.4
|
81.6
|
10.0
|
6.2
|
83.9
|
82.1
|
80.3
|
78.2
|
76.4
|
74.5
|
72.7
|
70.8
|
68.9
|
98.7
|
11.0
|
5.6
|
83.4
|
81.5
|
79.5
|
77.2
|
75.2
|
73.2
|
71.2
|
69.2
|
67.1
|
119.7
|
12.0
|
5.1
|
82.7
|
80.6
|
78.5
|
75.9
|
73.8
|
71.6
|
69.4
|
67.2
|
64.9
|
145.8
|
13.0
|
4.5
|
82.0
|
79.6
|
77.3
|
74.4
|
72.0
|
69.6
|
67.1
|
64.7
|
62.2
|
179.5
|
14.0
|
3.9
|
81.0
|
78.3
|
75.7
|
72.4
|
69.7
|
67.0
|
64.2
|
61.5
|
58.7
|
224.3
|
15.0
|
3.4
|
79.6
|
76.6
|
73.5
|
69.8
|
66.7
|
63.5
|
60.4
|
57.2
|
54.0
|
Source:
Table extracted from: Boiler Efficiency Institute, "Boiler Efficiency
Improvement" by David F. Dyer and Glennon Maples, Copyright 1991.
No comments:
Post a Comment