A boiler house burns natural gas with excess air in a furnace. The hot combustion gas flows through a heat exchanger, producing saturated steam at $50$ bar from feedwater that enters the heat exchanger at $20C.$

Perform the material balance on the furnace and the energy balance on the heat exchanger, given the information below:

$100\%$ conversion of the natural gas, the combustion is $100\%$ complete

air and natural gas enter the furnace at $25C$

natural gas is $100\%$ methane

$25\%$ excess air is fed to the furnace

the hot combustion gas leaves the furnace at $1000C$ and atmospheric pressure

the heat exchanger is adiabatic

How much steam can be produced per $kg$ of natural gas if the outlet combustion gas temperature from the heat exchanger is $100C?$ What is the dewpoint of the combustion gas?