What is the difference between superheated steam and saturated steam?

Saturated steam: Steam at a certain pressure when the gas and liquid phases are in equilibrium. Superheated steam: It is saturated steam that has been further heated, giving it a higher enthalpy value (in other words, more energy). It has the characteristic of not being easily reduced to water when releasing energy through work. Under normal circumstances, as long as the conditions are met, saturated steam can be used in the device. Superheated steam is generally used for special purposes, such as driving turbines. If I remember correctly, the steam transported over long distances is also superheated.

I agree with the second floor. By the way, I’d like to ask the guy upstairs: since superheated steam doesn’t easily revert to water while doing work, is it still in a gaseous state after the steam turbine has completed its work? Some of it must have condensed into water, right?

It can be said that there is no pure water vapor, right? Under any pressure conditions, vapor-liquid equilibrium always exists, that is, both the gas phase and the liquid phase are present at the same time :)

That’s because the temperature drops during the expansion process

1. Saturated steam: When a liquid evaporates in a confined space, the liquid molecules move through the surface of the liquid into the space above, turning into steam molecules. Due to the chaotic thermal motion of steam molecules, they collide with each other as well as with the container walls and the liquid surface. When colliding with the liquid surface, some molecules are attracted by the liquid molecules and return to the liquid to become part of it. At the start of evaporation, more molecules enter the space than those that return to the liquid. As evaporation continues, the density of vapor molecules in that space increases, which in turn leads to an increase in the number of molecules that return to the liquid. When the number of molecules entering the space per unit time is equal to the number of molecules returning to the liquid, evaporation and condensation are in dynamic equilibrium. At this point, although evaporation and condensation continue to occur, the density of vapor molecules in the space no longer increases; this state is known as a saturated state. A liquid in a saturated state is called a saturated liquid, and its vapor is called dry saturated vapor (also known as saturated vapor). 2. Superheated steam: Steam with a temperature higher than that of saturated steam is called superheated steam. ——:L

No, it is more likely to exist in the liquid phase or gas phase alone than when the two phases coexist

Saturated steam: Steam containing condensate water, with high heat transfer efficiency, such as steam generated directly by boilers. Superheated steam: Steam with a temperature higher than the condensation temperature at its corresponding steam pressure. Superheated steam is generally produced by depressurizing saturated steam, such as the steam generated after power generation in power plants. Its heat transfer efficiency is low, and water can be added to produce saturated steam.

At the same pressure, the temperature of superheated steam is higher than that of saturated steam! When water is heated, saturated steam is produced once the temperature reaches the saturation point. By continuing to heat the saturated steam, superheated steam can be obtained! Superheated steam is generally used in steam turbines, as the presence of a certain degree of superheat ensures the dryness of the steam after it performs work, thereby reducing corrosion of the turbine. Saturated steam is typically used in various heating applications, as most of the heat contained in such steam lies in its latent heat. At saturation temperature, saturated steam transitions from a gaseous state to a liquid state, releasing a large amount of latent heat that can be used to heat the material being processed

In chemical plants, steam transported through pipelines is usually superheated steam, which reduces heat losses during transportation, prevents the generation of large amounts of condensate when transporting saturated steam, and increases the transport capacity. Saturated steam is generally used with heating equipment. Depending on the heating temperature, superheated steam can be converted into saturated steam if saturated steam is required.

At a certain pressure, there is a corresponding temperature for the saturated steam. Steam with a temperature higher than this is superheated steam. When the temperature is below this value, steam condenses into water. At this temperature, the steam is saturated steam

Superheated steam is steam whose actual temperature is higher than the boiling point temperature at that pressure. Saturated vapor is vapor that does not contain any liquid.

I agree with what was said above: the density of superheated steam is lower than that of saturated steam at the same pressure, and the enthalpy of steam is lower

Superheated steam is gas for which, at a certain boiling point, there exists a fixed saturated vapor pressure; that is, condensation occurs easily at this pressure. However, if the conditions are controlled such that the temperature is higher than the boiling point at this saturated vapor pressure, then such gas is called superheated steam. Superheated steam, saturated steam: data includes specific volume, enthalpy, and entropy. It can be obtained by looking up a table.

It would be good if everyone could mention which devices use superheated steam; it seems that not many devices make use of it!

In my understanding, saturated steam refers to a state of equilibrium between water and water vapor. Superheated steam is this type of steam that has been further heated. In chemical production, in order to increase the temperature and pressure of steam, it is further heated, resulting in superheated steam.

It has a relatively low water content and is mainly used as a heat source driven by turbines, or for long-distance transportation.

Before and after being supplied to the turbine for power generation, the steam extracted from the power plant is superheated steam. In typical chemical processing units, the steam pressure does not need to be that high; even when the pressure decreases, as long as the temperature is not adjusted, it remains superheated steam； Adjusting the temperature appropriately according to pressure results in saturated steam. Superheated steam is used under special heating or other conditions, primarily to utilize temperature differences of gases for heating purposes, but its heat transfer coefficient is very low ； Slightly overheating on an industrial scale, when used for heating, ensures both efficient heat transfer and a significant improvement in heat exchange efficiency.

After superheated steam does work through the turbine, some of it condenses while some does not, depending on the design of the steam turbine. Under normal circumstances, condensing steam turbines have a higher efficiency.

Superheated steam does not produce excessive condensate, making it more suitable for long-distance transportation; for typical bottom reboilers, saturated steam is preferable