Exercise-1

1) A furnace is heated by combusting a gaseous fuel of composition and with dry air. The Orsat analysis of products of combustion (POC) is and Calculate the following on the basis of of gaseous fuel.

• Volume of POC at NTP, STP and at
• Volume of air at NTP
• Percent excess air
• in POC

SOLUTION:

a)Volume of POC ( Note that POC and flue gas are the same)

Consider of gaseous fuel at NTP ( 1 atm. and 273K). Let is POC (1atm,273K)

Performing Carbon balance:
; it follows that
,  hence
at NTP (1 atm and 273K)
at STP (1 atm and 298K)
at (1 atm and 1273K)

Note the increase in volume of POC at 1273 K which is around 5 times than at 273K. This knowledge is important in designing combustion chamber.

b)Volume of air

Let is the volume of air required at NTP . Performing nitrogen balance we get
, we get
, hence
at NTP