Mike,
thermal power plants work this way. Let's say that it's a conventional power plant.
Water coming from the deaerator is taken by the boiler feed pump and passes through the high pressure heaters and enters the boiler, precisely into the steam drum. From the steam drum, the water goes down to the mud drum, from where it's partially distributed to the water headers. From the mud drum the water enters the so called raiser tubes and it's directed to the steam drum. From the water headers the water is directed to the steam headers, and then to the steam drum. Somewhere in between the mud drum and the steam drum, and in between the water headers and the steam headers, the water evaporates and becomes humid steam. Humid steam means that it's not pure, rather, it contains water droplets.
In the steam drum the humid steam passes through the scrubber, which retains the water droplets. The steam that leaves the scrubber is saturated steam, whose definition you've given on your posting. From the steam drum the steam goes to the superheater tubes, where it becomes superheated, whose definition you've given on your posting. The superheated steam goes then to the high pressure section of the turbine where it expands, loosing pressure and temperature (remember the gas law PV = RT). Before being sent to the low pressure section of the turbine, the steam must be reheated to recover some (although not all) of its pressure and temperature. So, it goes back to the boiler, where this operation takes place.
The reheated steam is then sent to the low pressure section of the turbine, where, again, it expands and looses pressure and temperature. Somewhere before the last turbine stages the temperature and pressure losses have been so great that the steam becomes humid again. At this point, the steam velocity is low and no blade erosion will occur. When it leaves the last turbine stage and goes to the condenser, the steam is at a pressure below the atmospheric and at a temperature below 100 C or 212 F.
From the condenser, the water (called condensate in boiler room slang) is taken by the condensate pumps and sent first to the low pressure heaters and then to the deaerator, where the cycle starts all over again. This cycle is called the Rankine cycle and you can follow it, step by step, on the Mollier diagram.
Giovanni S. Crisi
PS 1. If you hate to read something that's not true, you better abandon this Forum, because I've seen a lot of incorrections written along the years that I frequent it.
PS 2. I've not been able to open the site attached to your second posting. Sorry.
Best regards
This link is sooo much better than the one you're offering Mike!
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