In an energy audit, the following information was obtained from the inspection of a boiler: Fuel:...

 

Transcribed Image Text:

In an energy audit, the following information was obtained from the inspection of a boiler: Fuel: Rating (input) Output: Exhaust Temperature: Exhaust Gas Analysis on dry basis: CO₂ 02 N2 Natural Gas 10 million (MM) Btu/hr Saturated Steam at 55 psig 450 F Calculate: 8.6% 5.6% Balance Assume 3% loss due to surface losses and blow-down. a - Fuel air ratio (assume that natural gas can be taken as methane) b - Mass flow rate of fuel and air c - Mass flow rate of steam generation if the feed water (water entering the boiler) is at 180 F. d - Maximum flame temperature that can be expected in the boiler? You may use an online calculator for this purpose. e - Boiler efficiency f- It is decided to recover heat from the exhaust by directing the feedwater through the heat exchanger to be installed on the exhaust stack, to cool the exhaust to 300 F. Calculate % of the energy saved by installing the heat exchanger (economizer). Submit your results along with a tech memo summarizing your results. In an energy audit, the following information was obtained from the inspection of a boiler: Fuel: Rating (input) Output: Exhaust Temperature: Exhaust Gas Analysis on dry basis: CO₂ 02 N2 Natural Gas 10 million (MM) Btu/hr Saturated Steam at 55 psig 450 F Calculate: 8.6% 5.6% Balance Assume 3% loss due to surface losses and blow-down. a - Fuel air ratio (assume that natural gas can be taken as methane) b - Mass flow rate of fuel and air c - Mass flow rate of steam generation if the feed water (water entering the boiler) is at 180 F. d - Maximum flame temperature that can be expected in the boiler? You may use an online calculator for this purpose. e - Boiler efficiency f- It is decided to recover heat from the exhaust by directing the feedwater through the heat exchanger to be installed on the exhaust stack, to cool the exhaust to 300 F. Calculate % of the energy saved by installing the heat exchanger (economizer). Submit your results along with a tech memo summarizing your results.

Answer rating: 100% (QA)

a Fuel air ratio Assuming the natural gas composition is pure methane CH4 the stoichiometric airtofuel ratio is 954 kg airkg fuel From the exhaust gas analysis the O2 concentration is 56 This indicate... View the full answer