Riello RS 280 - Procedure to Refer Burner Operating Condition in High Altitude Plants

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Technical description of the burner
3.8.1 Procedure to refer burner operating condition
in high altitude plants
Find the CORRECTED BURNER CAPACITY for the plant’s alti-
tude in chart 1 and the CORRECTED PRESSURE in chart 2.
Check in the firing rate graph of the burner (Fig. 5), if the working
point defined by the values above is within the range limits.
If not, higher burner size is needed.
Note
 Charts are based only on altitude variation (reference tem-
perature = 68°F, 20°C)
 To get the combined correction in case of different air tem-
perature, a compensation of 1000 ft each 3.6°F (305 m each
2°C) is applicable (100 ft = 0.36°F).
Example
– Rated Capacity = 5000 MBtu/hr
– Rated Air Pressure = 2.61 “WC
– Reference Altitude = 328 ft
– Reference Temperature = 20°C = 68°F
– Real Altitude = 3000 ft
– Real Temperature = 17°C = 62.6°F
– Temperature Difference = 68°F – 62.6°F = 5,4°F
– Virtual Altitude Increment = 5.4°F/3.6°F x 1000 ft = 1500 ft
– Virtual Altitude = (Real Altitude) + (Virtual Altitude Increment) =
3000 ft + 1500 ft = 4500 ft
– Corrected Capacity = (5090+5113)/2 = 5101,5 MBtu/hr
– Corrected Pressure = (4.41+4.87)/2 = 4.64 “WC
Reference conditions:
– Ambient temperature 68 °F (20 °C)
– Barometric pressure 394” WC (1000 mbar)
– Altitude 328 ft a.s.l. (100 m a.s.l.).
CORRECTED BURNER CAPACITY ACCORDING TO ALTITUDE
Altitude
Rated Capacity
m a.s.l. 0 100 305 610 915 1220 1525 1830 2135 2440
ft a.s.l 0 328 1000 2000 3000 4000 5000 6000 7000 8000
1000 995 1000 1011 1029 1048 1068 1090 1113 1137 1163 995
2333 2328 2333 2344 2362 2381 2401 2423 2446 2470 2496 2328
3667 3662 3667 3678 3696 3715 3735 3757 3780 3804 3830 3662
5000 4995 5000 5011 5029 5048 5068 5090 5113 5137 5163 4995
6333 6328 6333 6344 6362 6381 6401 6423 6446 6470 6496 6328
7667 7662 7667 7678 7696 7715 7735 7757 7780 7804 7830 7662
9000 8995 9000 9011 9029 9048 9068 9090 9113 9137 9163 8995
10333 10328 10333 10344 10362 10381 10401 10423 10446 10470 10496 10328
11667 11662 11667 11678 11696 11715 11735 11757 11780 11804 11830 11662
13000 12995 13000 13011 13029 13048 13068 13090 13113 13137 13163 12995
Average barometric
pressure (20°C)
mbar 1013 1000 977.4 942.8 908.2 875.8 843.5 811.85 779.8 747.8
Average barometric
pressure (68°F)
"w.c. 399 394 385 371 358 345 332 320 307 294
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