Temperature dilution

["Paul S. Anderson" <psanders@ilstu.edu>]

At 09:14 AM 5/23/02 +0100, AJH wrote:

>Prasad hinted at the fact that combustion efficiency must not be seen
>only as completeness of combustion because this can be achieved at the
>expense of copious amounts of excess air. This raises the mass flow
>and dilutes the temperature. This lower temperature has implications
>for poor heat transfer. IMO the higher grade the fuel the lower excess
>air required to reach an equilibrium which produces an acceptable
>level of pollutants.

Please consider if the problem of "temperature dilution" (mentioned in the 
above paragraph) would be less of a problem if the air entering was already 
at a high temperature.  And I mean at a VERY high temperature, as hot as 
you can get it.

Has research been done on the impact of pre-heated primary and/or 
pre-heated secondary air?  Anyone have references?

Tom Reed was just here in Illinois, so he is on the road and will not get 
this message for several days.  While here he said that the denser (cooler) 
air was better able to force its way into a body of gases than would warmer 
air, meaning better mixing of air and gas if the air was cooler.  I said to 
Tom that I believe in the value of pre-heated air and therefore we need to 
consider how to do better mixing.   (Then he left, and the conversation 
remains open.)

I would think this is pretty basic information that merits data collection 
if data are not already available.

Paul
Paul S. Anderson, Ph.D.,  Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL  61790-4400   Voice:  309-438-7360;  FAX:  309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders


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