How does the super heater raise the temperature of steam with out raising pressure?

Answer 1

Steam behaves as an ideal gas as long as it is not condensing. That means PV = nRT. The term super heat just means you are heating the vapor above the saturation point.

Since you are adding temperature to this ideal gas, PV must increase. You mentioned. P (pressure) does not increase during superheat. The answer is simple, the steam is allowed to expand. Because the ideal gas law here just says that the product of pressure and volume must increase, if volume is increased by enough (that is, the steam is allowed to expand at constant pressure) there will be no pressure increase.

Answer 2

Steam is like any other gas, it can be heated to higher temperatures without increasing pressure .. However, the volume will increase at constant pressure and, it is at a temperature above its saturation temperature and becomes superheated steam.

Answer 3

A superheater is a device in a steam engine that heats the steam generated by the boiler again, increasing its thermal energy and decreasing the likelihood that it will condense inside the engine. Superheaters increase the efficiency of the steam engine, and were widely adopted. Steam which has been superheated is logically known as superheated steam; non-superheated steam is called saturated steam or wet steam. Superheaters were applied to steam locomotives in quantity from the early 20th century, to most steam vehicles, and to stationary steam engines including power stations.

In physics, superheating (sometimes referred to as boiling retardation, or boiling delay) is the phenomenon in which a liquid is heated to a temperature higher than its standard boiling point, without actually boiling. This can be caused by rapidly heating a homogeneous substance while leaving it undisturbed (so as to avoid the introduction of bubbles at nucleation sites).

Because a superheated liquid is the result of artificial circumstances, it is metastable, and is disrupted as soon as the circumstances abate, leading to the liquid boiling very suddenly and violently (a steam explosion). Superheating is sometimes a concern with microwave ovens, some of which can quickly heat water without physical disturbance. A person agitating a container full of superheated water by attempting to remove it from a microwave could easily be scalded.

Superheating is common when a person puts an undisturbed cup of water into the microwave and heats it. Once finished, the water appears to have not come to a boil. Once the water is disturbed, it violently comes to a boil. This can be simply from contact with the cup, or the addition of substances like instant coffee or sugar, which could result in hot scalding water shooting out. The chances of superheating is more common with smooth containers, such as brand-new glassware that lacks any scratches (scratches can house small pockets of air, which can serve as a nucleation point).

Rotating dishes in modern microwave ovens can also provide enough perturbation to prevent superheating.

There have been some injuries by superheating water, such as when a person makes instant coffee and adds the coffee to the superheated water[1]. This sometimes results in an "explosion" of bubbles. There are some ways to prevent superheating in a microwave oven, such as putting a popsicle stick in the glass, or having a scratched container to boil the water in.

Answer 4

By increasing the volume. PV=nRT, so when V increases, T increases