Question 1: One of your fellow Energy Engineers comments that the flue gas leaving the natural gas-fired boiler that you are designing should be at a high temperature because of dew point. Your boss asks you to examine that argument by performing some calculations.

The natural gas boiler that you are designing uses a gas with a composition of CH₄-95% and C₂H₆ - 4% and other inert gases 1%. You have a coal fired facility next door and they use a coal with the following analysis C-73.4% H-4.3%, S-1.1%, N-1.3%. The fuel's proximate analysis is given as follows: Moisture 6.8%, Ash-8.6%, FC- 65.4 and VM 19.2%. The HHV of the Fuel is 13,380 BTUs/lb. The air that is used is ambient at 78 F and 40% relative humidity. This plant is designed to use 22% exc ess air.

Evaluate both cases and show to your boss with calculations whether the dew point is different? If so by how much? And what is the impact?

Question 2:

If 90% of the sulfur dioxide produced has to be captured from the coal fired power plant in problem 1 (500 MW Thermal) by using lime (CaO). What is the flow rate of the CaCO₃ that would be required if CaO is produced by calcining CaCO₃? The efficiency of sulfur capture is 65%.