INTRODUCTION
what is steam?
- is an invisible gas generated by adding heat energy to water in a boiler. Enough energy must be added to raise the temperature of the water to the boiling point.
- Then additional energy addition changes the water to steam – without any further increase in temperature.
- Steam is a very efficient and easily controlled heat transfer medium.
- It is most often used for transporting energy from a central location (the boiler) to any number of locations in the plant where it is used to heat air, water or process applications.
why is steam used?
- steam is an efficient heat transfer medium
- steam is easily controlled
- we have a lot of knowledge concerning steam
- we have developed the equipment and expertise to design and install steam systems for many different applications
How do we create steam?
- steam is created by adding heat energy to water
- heat energy is expressed in Btu's.
Definitions:
The Btu:
a Btu--British thermal unit1Btu is the amount of heat energy required to raise the temperature of 1pound of water by 1F
Temperature :
the degree of hotness with no implication of the amount of heat energy available.
Heat:
a measure of energy available with no implication of temperature .to illustrates the one Btu that raises one pound of water from 39 0 f to 40 F could come from the surrounding air at a temperature of 70 F from a flame at a temperature of 1000 F.
the heat energy required to create steam is:
SENSIBLE HEAT:
is the amount of heat energy required to raise the temperature of water from 32oF to boiling point(saturated liquid)at a given pressure
-sensible heat raises the temperature of the water and can be sensed with a thermometer
LATENT HEAT:
is the amount of heat energy required to transform water at the boiling point (saturated liquid )to steam
-adding latent heat does not raise the temperature saturated liquid and steam have the same temperature for a given pressure remember:
the latent heat added at the boiler is what we have available to do work in our equipment but when we remove latent we create condensate
