-----Original Message----- From: Hoyt A. Stearns Jr. [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 12, 2007 5:51 PM To: [email protected] Subject: RE: [Vo]:Mostly Wasted
As I recall from thermodynamics courses, you can increase the efficiency of turbomachinery using intercooling ( cooling the fluid between each compressor stage ( for gas turbines )), and reheat ( adding heat between each stage in the expansion array ). This brings the cycle closer to a Carnot cycle. Large coal and oil fired boilers have a pendant tube section that reheats the steam between the high pressure turbine and the intermediate turbine. Steam to both the HP and IP turbines is superheated to prevent water droplets in these sections. Reheat of the LP steam is not done because it was never practical. Nuke plants cannot develop superheat, so the steam to these turbines is always wet. The turbine blades are grooved to channel the moisture which minimizes erosion damage. Jeff I've heard having liquid droplets in the turbomachinery causes severe erosion on turbine blades ( but maybe sonofusion would make up the difference :-) ). Hoyt Stearns Scottsdale, Arizona US http://HoytStearns.com -----Original Message----- From: Horace Heffner [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 12, 2007 3:18 PM To: [email protected] Subject: Re: [Vo]:Mostly Wasted On Dec 12, 2007, at 8:58 AM, Jones Beene wrote: > Horace > >> Do you know what temperature is available post turbine, prior to >> cooling? That means prior to the condenser, which is part of the >> cooling process, true? > > Most often, at least in modern plants, this heat is already being > utilized by a "recuperator" and is therefore unavailable. AFAIK, recuperators are used with gas turbines, not steam turbines. Gas turbines with recuperators can be way more efficient than steam turbines, and there is still heat left over for other uses, possible including recovery by use of Sterling engines for some of the energy recovery. Energy in the form of electricity is way more valuable than energy in the form of heat, so it would seem like there might be a niche there even with gas turbines. One of the problems with gas turbines is obtaining the gas from coal. If a significant amount of electrical energy could be recovered then maybe it could be used to pyrolize the coal to make coal gas. Just thinking out loud here. Horace Heffner http://www.mtaonline.net/~hheffner/ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.1/1181 - Release Date: 12/11/2007 5:05 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.1/1181 - Release Date: 12/11/2007 5:05 PM
