How does high altitude affect the steam boiler?

Combustion is a process which needs constant air supply for its survival, but as we move up the earth i.e. at higher altitudes, things aren’t the same as they used to be at sea level. Due to decreased air density at higher altitude, it will consume the same volume of air but will not consume the same mass of air.

This results in less fuel consumption & less steam generation rate. Due to the reduction of mass flow of gases through tubes of a steam boiler, convective heat transfer also decreases which further results in reduced evaporation rates.

At higher altitudes, atmospheric temperature decreases, so to increase the Boiler Efficiency one must focus on increasing the temperature of feed water and air.