ENGINEMAN 1 & C
Table 7-6.Calculated Trisodium Phosphate Dosages For Some Natural Circulation Auxiliary Boilers (Trisodium Phosphate,
Dodecahydrate Na3Po412H2O)
Boiler Water
Alkalinity
epm (meg/L)
84
215
280
300
Required to Raise Alkalinity to 2.0 epm (2.0 meq/L)
0.1
8
0.2
7.5
0.3
7
0.4
6.5
0.5
6.5
0.6
6
0.7
5.5
0.8
5
0.9
4.5
1.0
4
1.1
4
1.2
3.5
1.3
3
1.4
2.5
1.5
2
1.6
1.5
1.7
1.5
1.8
1
1.9
0.5
Boiler Water Volume at Normal Steaming Level
(Gallons)
Ounces of TSP
1 ounce = 28.35 grams
1 gallon = 3.785 liters
TSP - Trisodium Phosphate
20.5
19.5
18.5
17
16
15
14
13
12
10.5
9.5
8.5
7.5
26.5
28.5
180
25
21
170
24
25.5
160
22.5
24
150
21
22.5
140
19.5
21
130
18
19.5
120
17
18
110
15.5
16.5
100
14
15
90
12.5
13.5
90
11
12
80
10
10.5
70
8.5
9
60
7
7.5
50
5.5
6
40
4
4.5
30
3
3
20
1.5
1.5
10
Add
to
Current
Phosphate
6.5
5.5
4.5
3
2
1
3. Continue to the last column to find the
phosphate correction. This is the amount the
phosphate will increase due to the TSP. Record
the phosphate correction in the log.
4. Add the phosphate correction caused by
TSP to the measured boiler water phosphate. This
gives the corrected phosphate concentration;
record this in the log.
5. Proceed to table 7-5. Locate the corrected
phosphate in the first column. Read across the
table to the weight of DSP required for the
correct volume. (Use table 7-7 for the vessels listed
earlier.) Enter this weight in the log.
6. Weigh the chemicals, dissolve them
together in the 10-liter safety dispensing bottle,
and inject the solution into the boiler.
NOTE: TSP must be dissolved in cold feed-
water since TSP generates heat when dissolving.
DSP must be dissolved in hot feedwater if only
DSP will be injected into the boiler. Therefore,
TSP should be added first to cold water in the
bottle, then dissolved. This will generate sufficient
7-14