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Stack Temperature,Refractory/Insulation programs V.Ganapathy

This package has 3 programs:
Heat loss through multi-layered insulation/refractory
Circular stack/duct wall temperature,heat loss calculations
Acid dew point calculations

Heat loss through multi-layered Insulation/refractory
Heat loss through multi-layered insulation/refractory(up to 6 layers) and intermediate layer temperatures in circular or rectangular ducts can be computed by this program.You can create your own list of insulation/refractory-up to 35 names by inputting their temperature vs k values at four different points.The program comes with AP Green insulation/refractory data     but they can be easily altered to include your own list.Program runs in both British and Metric units.

Example:A 2 layered refractory in a flat plate has a hot face temperature of 1900 F.The first layer is 4 in thick and made of AP Green ks4 and the second layer is 3 in thick of castable block mix. The ambient temperature is 90 F,wind velocity =120 ft/min,casing emissivity=0.9.
 
Input/output from the program
Data 
project - sample 
units- British 
surface-flat 
hot face temperature-1900 F 
ambient temperature-90 F 
wind velocity-120 ft/min 
casing emissivity-0.9 
layer1 -ks4 - 4 in 
layer2-cbm -3  in 
 
Results  
project-sample units-British 
layer name     thick temp in temp out 
                         in        F           F 
1    ks4-2550      4      1902       1626 
2    cbm-1600     3      1626        225 
amb temp-F=90 hot face-F=1900 
wind vel-fpm=120 emiss=.9 
heat loss-Btu/ft2h=428 
max heat loss-(no insuln)-Btu/ft2h=53940
 Note that due to the iteration process the hot face temperature after the calculations may be slightly different from the actual value. Also,the names of the refractory as shown above can have some attributes such as maximum temperature of operation etc.When you develop your own list,you may do so for your refractory/insulation. The program also proints out the heat loss with and without refractory. Circular ducts is also handled by the program.

Stack/Duct temperature calculations
This program predicts the exit gas temperature,heat loss,wall temperatures of circular ducts/stacks.Wall temperatures give an idea if corrosion is likely to occur.Program runs in both British and Metric units.

Example:78,000 lb/h or boiler flue gases at 400 F enter a circular stack of diameter 36 in.Gas pressure is 14.5 psia,stack wall thickness=1.5 in,stack height=45 ft.Gas analysis:% vol co2=8,h2o=18,n2=71,o2=3. Ambient temperature=80F and wind velocity=440 ft/min.Deterine the stack wall temperatures,heat loss and exit gas temperature.
Inputs/outputs from the program are shown below.
 
Data 
project - sample   units-British 
ambient temperature-F=80 
wind velocity-ft/min=440 
gas pressure-psia=14.5 
gas inlet temperature-F=400 
stack diameter-in=36 
stack thickness-in=1.5 
stack height-ft=45 
% vol co2=8 h2o=18 n2=71 o2=3
Results 
heat loss from stack-Btu/ft2h=752 
stack inner wall temperature-F=253 
stack outer wall temperature-F=249 
gas heat transfer coefficient-Btu/ft2hF=5.83 
exit gas temperature-F=384 
stack gas velocity-ft/min=4084 
gas mol wt=27.6
Acid Dew Point calculations
The program computes the dew points of several vapors such as water vapor,hydrochloric acid,nitric acid,hydrobromic acid,sulfuric acid given the gas pressure and alanysis in % volume.For sulfuric acid,either the % so2 volume and % conversion from so2 to so3 or the ppm of so3 should be given.Program runs in Metric and British units.

Example:A  flue gas at 14.5 psia contains in % volume-water vapor-12,hydrochloric acid vapor-1,so2=1.% conversion of so2 to so3 is 2. Determine the dew points of the vapors.Note that we could also have inputted % volume of hrdrobromic and nitric acid vapors and their dew points would be computed.
 
Data 
project-sample units-British 
gas pressure-14.5 psia 
% vol h2o-12 
     hbr- 
     hcl-1 
     hno3- 
     so2-1  % conversion-2
Results 
wat vap dew pt -123 F 
Hcl dew pt  - 146 F 
Hbr dew point- 
Hno3 dew pt- 
ppm so3-160 
h2so4 dew pt-336 F 
 
[the correlations used for acid dew points are shown in my books. See the article on economizer corrosion ]

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