UFC 3-240-13FN
25 May 2005
Steam Generation, and COC.....................................................
42
3-1.5.6
Calculating Blowdown Rates .....................................................
42
3-1.5.7
Determining Feedwater and Blowdown Rates...........................
42
3-1.6
Determining Makeup Water and Condensate Return Rates .....
43
3-1.6.1
Makeup Water Rate...................................................................
44
3-1.6.2
Condensate Return Rate ...........................................................
44
3-1.6.3
Difference Between Amount of Steam Produced and
Amount of Condensate ..............................................................
45
3-1.6.4
Basis for Evaluating Boiler System Efficiency ...........................
45
3-2
BOILER WATER TREATMENT AND CONTROL ..............................
45
3-2.1
Boiler Deposit Formation ...........................................................
46
3-2.1.1
Scale..........................................................................................
46
3-2.1.2
Sludge Deposits.........................................................................
46
3-2.1.3
Dissolved Solid Materials...........................................................
46
3-2.2
Common Scale Found in Boilers ...............................................
47
3-2.2.1
Calcium Carbonate ....................................................................
47
3-2.2.2
Calcium Sulfate..........................................................................
47
3-2.2.3
Calcium Phosphate....................................................................
47
3-2.2.4
Magnesium Phosphate ..............................................................
47
3-2.2.5
Magnesium Silicate....................................................................
47
3-2.2.6
Iron Oxide and Iron Hydroxide ...................................................
48
3-2.3
External Boiler Water Treatment ...............................................
48
3-2.3.1
External Water Treatment for High-Pressure Boilers ................
48
3-2.3.2
External Treatment for Low-Pressure Boilers ............................
48
3-2.4
Internal Treatment of Boiler Water.............................................
48
3-2.4.1
Preventing Scale Formation ......................................................
48
3-2.4.1.1
Low-Pressure Boilers.................................................................
49
3-2.4.1.2
High-Pressure Boilers................................................................
49
3-2.4.2
Determining Chemical Treatment Feed Rates ..........................
50
3-2.4.3
Preventing Sludge Deposits ......................................................
51
3-2.5
Corrosion in the Boiler ...............................................................
51
3-2.5.1
General Corrosion .....................................................................
51
3-2.5.1.1
Proper pH for Boilers up to 6205 Kilopascals ............................
52
3-2.5.1.2
Proper pH for Boilers Over 6205 Kilopascals ............................
52
3-2.5.2
Pitting Corrosion ........................................................................
52
3-2.5.3
Other Types of Corrosion ..........................................................
52
3-2.6
Removing Oxygen from Feedwater ...........................................
52
3-2.6.1
Mechanical Oxygen Removal ....................................................
53
3-2.6.1.1
Deaerator Operation ..................................................................
53
3-2.6.2
Chemical Removal of Free Oxygen ...........................................
55
3-2.6.2.1
Oxygen Scavengers for Boilers up to 6205 Kilopascals ............
55
3-2.6.2.2
Oxygen Scavengers for Boilers Over 6205 Kilopascals ............
55
3-2.7
Condensate Corrosion and Control ...........................................
57
3-2.7.1
Causes of Condensate Corrosion..............................................
57
3-2.7.1.1
Air ..........................................................................................
57
3-2.7.1.2
Carbon Dioxide ..........................................................................
57
3-2.7.2
Estimating Carbon Dioxide in Steam .........................................
58
3-2.7.3
Control of Carbon Dioxide by Neutralizing Amines....................
59
3-2.7.3.1
Control Limits.............................................................................
59
3-2.7.3.2
Vapor-Liquid Distribution Ratios ................................................
59
3-2.7.3.3
Morpholine .................................................................................
61
3-2.7.3.4
DEAE .........................................................................................
61
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