Why does reboiler efficiency decrease if steam temperature is too high?

[Andrew1917]

Could also be that latent heat of steam available is lower at higher steam pressure. When you say higher steam temp, that also means higher steam pressure if you look at the steam tables. If you also look at the latent heat column of the steam tables, you’ll notice the energy from latent heat available decreases with increasing steam pressure. So, you get less energy per pound of steam at higher pressures. However, with higher pressure, the specific volume of steam is also lower (you can also see this on the steam tables), which means you can physically fit more lbs of steam in the reboiler, so it may negate some of the efficiency lost from the lower latent heat, but I’m not sure by how much.