Why does higher-temperature steam require a greater quantity to transfer the same energy, unlike other heat sources?

Question

Typically, a higher-temperature heat source requires a smaller quantity, but with steam, calculations show that as temperature increases, a greater amount of steam is needed. I understand that this is due to the decrease in steam's latent heat at higher temperatures, resulting in an increased steam requirement. However, this seems counterintuitive, so I would like to ask:

1. In practical applications of steam, does usage align with calculations, indicating that higher temperatures require more steam?
2. If practical steam usage contradicts these calculations, is there an alternative method for estimating steam quantities that better reflects actual conditions?
3. Could you please provide an example calculation comparing heat sources at different temperatures for the same energy requirement?

I seek this explanation for a technical argument, so any insights from those knowledgeable in this area would be greatly appreciated.

Additional information: I need to determine the amount of steam produced by a steam transformer at a rate of 106,535 kg/h with a temperature of 118 °C for use in other processes. The energy source for this steam transformer is exhaust steam. In this setup, the feedwater amount, the amount of steam produced, and the target temperature remain constant. The only variable factor is the exhaust steam.

Additional images are attached to provide example of calculating steam consumption when steam pressure changes. It was found that as pressure increases (and temperature rises), steam consumption also increases accordingly.

Answer 1

This is due to pressure, not temperture.

This is saturated saturated steam. The heat of vaporization goes down with an increase in pressure because it takes less energy to transition to gas from liquid. Look at it as higher pressure gas is closer to liquid already.

While we're at it, these low pressures are below the top of the enthalpy curve where boilers typically run, where total enthalpy isn't changing very much with pressure, 1202-1205 Btu/lb in freedom units. I guess you SI guys & gals know what that number is off the top of your head like I do for imperial.

Superheated steam will directly increase the enthalpy as you increase the temperature, since we aren't dealing with phase change.