Steam Power

Power plant operator here: I'll give you a brief description of our basic steam cycle.

1. Water starts in condenser hotwell, it then passes through what we call condensate pumps, raising pressure to about 200 psi.

2. From the condesate pumps, water passes though a series of feedwater heaters, the purpose of these is to increase efficiency, by reclaiming heat that would otherwise be lost.

3. After passing through those feedwater heaters, the water passes though what is called a boiler feed pump, this is steam driven and is two pumps in series. Pressure is raised from 200psi to nearly 3000psi (load depending)

4. From the boiler feed pumps, the water then passes though the high pressure feedwater heaters, further adding heat to the water and increasing efficiency.

5. After the last feedwater heater, water enters the boiler passing through the economizer, this is the coolest section of the boiler where heated gasses are just about to exit the boiler.

6. From the econmizer the water passes though a series of tube bundles that are in the boiler furnace, at this point the water is heated to a point where it becomes superheated steam. Circulation of water in boiler is assisted with 3 large boiler circ pumps.

7. Steam leaves boiler and heads to the steam turbine, it's energy is imparted onto the blading of the high pressure turbine, causing it to rotate. Steam exits the high pressure turbine and is returned to the boiler as what we call cold reheat steam. This steam is "reheated" and passes though the intermediate pressure turbine.

8. After exiting the intermediate pressure turbine, steam passes through two low pressure turbines. All of the turbines I have mentioned are driving a common shaft, which of course, is attached to a generator. Steam enters the high pressure turbine at about 2800psi and leaves at low pressure turbines at 25" vacuum.

9. As the steam leaves the low pressure turbines, it is cooled and condensed in the main condenser and returned to liquid form. This leads us back to step 1 and we start all over.

Here is how the fire side of the boiler works.

1. Coal feeds from 8 large silos into 8 seperate pulverizers. The pulverizers grind the coal into a talcum powder like consistancy.

2. Large fans blow this coal from the pulverizer into the boiler though adjustable nozzles that are arranged on the corners of the boiler at 8 seperate levels. This coal dust is initially ignited with fuel oil, but once fire is established it's self sustaining. These nozzles create a spinning fireball in the center of the furnace. Our furnace is comprised of 2 boxes, 45'x45'x130'

3. 2 even larger fans provide adequate combustion air to sustain the fireball. Heat is forced though a series of close to 50 miles of boiler tube. It is in these tubes that the water is turned to steam.

4. 2 5000HP fans on the exit of the boiler ensure that gasses are pulled completely though and expelled though a series of emissions reducing systems before discharge to the atmosphere.

5. Ash that collects on these tubes is periodically removed by sootblowers, their purpose is to use high pressure steam to blow the collected ash off the boiler tubes, thereby ensuring good heat transfer. Ash is collected in water filled hoppers at the bottom of the boiler and removed with a wet conveyor system.

In a nutshell, that's it....that is the quick and dirty. I could go on and on and on, as there are numerous systems and subsystems not mentioned.