Research topic for master thesis related to energy conservation at power plant 1

If you work at a power plant, I would think you should be able to come up with many, many ways to conserve energy and improve heat rate.

I suggest you review the published papers by Weizhong Feng, of shanghai's Waigaoxiao power plant. He has publishecd many proven improvements applicable to large coal fired power plants which have not yet been incorporated in US power plants. see this linnk for a start<blogs.wsj.com/chinarealtime/2010/03/10/behind-a-power-plants-efficiency-drive/>

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

I disagree with Dave. Don't waste your time with coal plants. Having worked for two large power generation utilities, I can say for certain, coal plants are the bastard child of the industry. They keep them, but they aren't going to spend money on them if they don't have to. CCGTs are the better option. They are the first units to get dispatched and are what will continue to be built for the foreseeable future. If you can get an older CCGT (52-55% efficient) to get closer to what the newer units achieve (58-62%), that will make a bigger difference that making a 32% efficient coal unit 40% efficient. The coal unit will still be near the bottom of the dispatch list.

If you focus on CCGT plants , you would need to recognize that the new method of operation is mostly 2-shift operation with daily startups and very fast startups, as opposed to the older design objective of base load operation . The older method was able to focus on high cycle efficiency while basically ignoring the startup /shutdown losses and limitations, while the new requirements force the designer to recognize fatigue damage caused by frequent load cycling and fast startups. Also, the economic payback for high cycle efficiency was made possible 10 yrs ago by a high cost of natural gas and a high plant capacity factor. Current US conditions are a low cost of fuel gas and a low capacity factor , with a premium paid for power avaialble from very fast startups.

The higher cycle efficiency available for base load designed CCGT units was made posible by the use of high Tit ( made possible by advanced gas turbine blade materials and very high efficiency compressor blade designs) , high steam pressures, double reheat steam cycles, wet compression for the CTG compressor, recovery of compressor work energy by use of a fuel gas heater or LP evaporator, and a variable speed BFP drive . Few of these design factors can be retrofit onto an existing CCGT plant. Also, these same design factors also hinder fast startups and worsen the fatigue damage that occurs during very fast startups.

Fast startups and low fatigue damage is typically achieved by using thin wall pressure parts ( which implies either a lower design pressure or the use of a once thru steam generator in lieu of a drum type unit), using design codes that recognize fatigue damage ( en 12952-3 annex C), installing mid wall thermocouples in thick pressure parts to monitor thermal stress during fast startups, 100% capacity HRH vent to atmosphere, final attemporators, electrically heated SCR NH3 heating gas, oversized demin storage tank, and fully automated startups . Some of these items can be retrofit, but these design objectives are different than the objectives used for a base load designed unit with a high capacity factor and a high cost of fuel gas.



"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

Correction: "high steam pressure, single reheat cycles"- there are no existing double reheat steam cycles on CCGT plants.

Items that could be retrofit on existing CCGT plants to improve efficiency may include:
a) compressor wet compression fogger nozzles, if permitted by OEM
b) VS BFP drive
c) VS ACC fan drives
d) improved ACC blades, as per Braunswerk ( netherlands)
e) control stack exhaust temperature to equal 5F over the acid dew point temperature , based on the average of the exhasut temp and the lowest tube metal temperature.

Coal fired plants have many areas that can be improved, but they are a dying breed, as MFJewell pointed out.


"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

davefitz said:

If you focus on CCGT plants , you would need to recognize that the new method of operation is mostly 2-shift operation with daily startups and very fast startups

Click to expand...

That depends on the ISO and who owns the plant (merchant versus regulated utility). Many new CCGTs startup and run baseload for years because the heat rate is good enough that they are much more economical than running older units. At the last utility I was at, most of our CCGTs ran 70% or more capacity factor, so of the newest units were in the 90%+ range.