Micro CoGen.

Heat exchangers/thermal storage => Coolant & Exhaust exchangers => Topic started by: squarebob on May 25, 2010, 12:22:25 PM

Title: Direct contact heat exchanger
Post by: squarebob on May 25, 2010, 12:22:25 PM
Has anyone tried this type of exchanger on an IC engine? I installed a bunch of them on boilers in the 90's. The transfer medium is a bunch of pall rings.

The hot gas enters the direct contact exchanger inlet (3) and travels upward through a high efficiency packed bed (4) with "X" sq. ft./cu. ft. of active heat transfer surface area.   Cool water is introduced at the top of the unit through a liquid distributor (5) where it comes into intimate counter current contact with the hot gas in the packed bed as it travels downward.  Sensible heat transfer between the colder water and hot gas occurs resulting in rapid heat up of the water.  The heated water drains into the sump section (6) and is pumped (7) through a plate and frame or shell and tube heat exchanger  to reheat return heat transfer liquid in a complete closed loop cycle.  Cleaned reduced temperature gas now saturated with water vapor exits out of the top of the unit (9).

I hope the pics attach.

Bob


Title: Re: Direct contact heat exchanger
Post by: billswan on May 25, 2010, 05:37:01 PM
welcome aboard squarebob

If the IC engine ran on propane or natural gas it might work but like jens said a diesel power plant puts out way to much carbon. But we sure would like to hear more about the systems you put in. What fuel, how big, did the water become acid, was the water filtered? What part of the country? Cost?

Billswan
Title: Re: Direct contact heat exchanger
Post by: Ronmar on May 25, 2010, 06:18:27 PM
I think if the surface area of the Conduction media had enough water flow to remain wet, the carbon would have no surface to bond to.  I think This would result in the carbon condensing in the water and being carried down with the water flow to the lower chamber. If the flow was allowed to slow at some point, the carbon should fall out of suspension.  It should make for easy carbon collection/cleaning.  I was going to play around with this, but I was concerned about water consumption thru evaporation, and the ultimate water chemestry.  Is it going to make sulfuric acid?
Title: Re: Direct contact heat exchanger
Post by: Westcliffe01 on May 25, 2010, 07:24:31 PM
Ronmar, the potential problem with this line of thinking is that the carbon produced in an IC diesel engine of this nature does not resemble toner.  It varies from a tarry hydrocarbon which would float on the water to popcorn like.  Generally, both types are in play if some load variation is involved and it is highly likely that it would tend to form crusty layers on anything it settled on.

Quote from: Ronmar on May 25, 2010, 06:18:27 PM
If the flow was allowed to slow at some point, the carbon should fall out of suspension.  It should make for easy carbon collection/cleaning. 
Title: Re: Direct contact heat exchanger
Post by: highwater on May 25, 2010, 09:43:33 PM
Water discharge exhaust.

Slightly related paper by the EPA on water disharge exhaust for small watercraft.

http://www.epa.gov/owow/oceans/regulatory/unds/TDDdocuments/appAboatNOD.pdf

Analysis on the composistion of contaminants contained in the discharge.

Read far enough and you'll get to the small diesel engines.

Randall