Page 197 - Boiler plant and distribution system optimization manual

182 Boiler Plant and Distribution System Optimization Manual

for an oxygen (O ) level of 2%. See Table 11-2. BOILER STACK GAS LOSSES
2
(Ans.: 9.9%)
The purpose of this section is to learn how to
determine combustion efficiency using prepared
3. Find the excess air when firing bituminous
tables.
coal for an oxygen (O ) level of 5%. See Table
2
11-4. Explanation:
(Ans.: 29.9%) Using the Heat Loss Tables:
(a) Look up the fuel type being fired.
4. What is the ultimate CO value for the fol- (b) Locate the page with the closest exit gas tem-
2
lowing fuels? perature.
(c) Find in the table where the excess air and
Table Page (Ans.) net stack temperature intersect. This point
a. Natural Gas 11-1 226 (11.7%) will be the value of the dry gas heat losses,
b. No. 6 fuel oil 11-2 227 (16.7%) heat losses due to the formation of moisture
c. No 2 fuel oil 11-3 228 (15.7%) (steam) from the hydrogen in the fuel and
d. Kerosene 11-5 230 (15.1%) the losses from the moisture in the fuel.
e. No. 5 fuel oil 11-6 231 (16.3%)
f. Anthracite coal 11-7 232 (19.9%) Determine Heat Loss Efficiency of the fol-
lowing examples using the combustion tables.

Example 1.
Fuel Type No. 6 [See Table 11-2]
Carbon Dioxide 9.1%
Stack Temperature 560F [293C]
Air Temperature 60F [16C]
Net Temperature 500F [260C]

Efficiency ———— (Ans.: Loss 20.7% Efficiency 79.3%)

Example 2.
Fuel Type No.2 [See Table 11-3]
Oxygen 9%
Stack Temperature 420F [216C]
Air Temperature 80F [27C]
Net Temperature 340F [171C]

Efficiency (Ans.: Loss 16.5% Efficiency 83.5%)

Example 3.
Fuel Type Natural Gas [See Table 11-1]
Carbon Dioxide 8.9%
Stack Temperature 580F [304C]
Air Temperature 60F [160C]
Net Temperature 520F [271C]

Efficiency (Ans.: Loss 20.6% Efficiency 79.4%)