What happens to steam temperature when pressure is reduced?

What happens to steam temperature when pressure is reduced?

Energy Saving by Increase of Latent Heat by Pressure Reduction. For saturated steam, the higher the pressure is, the smaller the latent heat which the steam contains become, and the larger the sensible heat become. This means that, the higher pressure, the larger the heat quantity loss for using for indirect heating.

Why Desuperheating is done after pressure reduction?

Desuperheating systems are used to reduce the temperature of process steam by spraying water into superheated steam, thereby reducing its enthalpy. Steam-conditioning systems combine the desuperheating function with pressure reduction.

What are the effects of improper pressure reduction?

Excessive pressure drop will result in poor system performance and excessive energy consumption. Flow restrictions of any type in a system require higher operating pressures than are needed, resulting in higher energy consumption.

What is the difference between Attemperator and desuperheater?

An attemporator controls steam temperature while a desuperheater removes whatever superheat there is in steam and reduces the temperature to a point at or nearly at saturation temperature.

What is the relationship between steam pressure and temperature?

The higher the pressure of a boiler the more heat must be applied to make steam. With the increased pressure, you in turn get steam at higher temperatures. Higher temperature steam contains more energy per pound, which is known as Enthalpy.

What does Desuperheating mean?

Desuperheating is the process by which superheated steam is restored to its saturated state, or the superheat temperature is reduced. Most desuperheaters used to restore the saturated state produce discharge temperatures approaching saturation (typically to within 3°C of the saturation temperature as a minimum).

Why superheated steam is not used for heating?

Superheated steam is also not useful for heating, but it has more energy and can do more work than saturated steam, but the heat content is much less useful. This is because superheated steam has the same heat transfer coefficient of air, making it an insulator – a poor conductor of heat.

How do you reduce pressure loss?

Tube side pressure drop can be lowered in following ways: Increasing the shell diameter. Increasing the shell diameter increases tube flow area due to increased number of tubes and, thereby, reduces tube flow velocity and, hence, reduces tube side pressure drop.

What is desuperheater of steam?

A desuperheater device injects a controlled amount of water into the superheated steam. The steam temperature is reduced by evaporative cooling from the water being injected into the superheated steam thereby lowering the temperature to allow for more efficient downstream use of the steam.

Which material are used for superheater tubes?

These tubes are constructed from steel alloy material because of their high operating temperature. The main difference between superheaters and reheaters is the steam pressure (Kitto and Stultz, 2005).

How does steam pressure reduction affect the steam system?

Steam pressure reduction affects mainly the high pressure part of the steam system. Within practical limits, pressure-reducing valves (PRVs) will adjust the pressure at lower levels to the previous set points. This means that most of the savings benefits from pressure reduction occurs in the high pressure section of the steam system.

What happens to pressure when you reduce a pipe?

In other words, when you reduce a pipe or hose, the flow does not increase; however, you will feel more pressure. So, it is a choice of reduced flow and increased pressure and vice versa. The same concept is relevant in sprinkler systems. Sprinklers with smaller pipes are likely to experience reduced flow but have increased pressure.

What are the effects of incorrect steam line sizing?

Many of the problems involve incorrect steam and condensate line pipe sizing (see “Pipe friction data”). The effects of these errors range from noise and erosion to equipment damage, erratic process control, safety hazards, and higher fuel costs.

What are the requirements for a steam pressure reducing valve?

To summarize: the steam pressure-reducing valve must be able to operate successfully at the minimum steam flow rates as well as the maximum flow rates. Figure 1: Two-Stage Steam Pressure-Reducing Station