Using genset exhaust for drying

[crimson]

Hello everybody.
This is my first post in this forum.
Has anyone ever tried to use the genset exhaust to dry e.g. woodchips in a dryer(e.g. rotary or linear type)?
According to my calculations, for a woodgas that contains 20% H2 the exhaust will contain ~10% of its mass water.(basic chemistry equations for woodgas burn)
If you use a 100 kw genset running 100% on woodgas you will have about 560-580 kgr/hour of exhaust gas at about 400 oC(turbocharged gas genset).
So, you must anticipate about 56-58 kgr/hour of water in your exhaust.
I am not an expert in engines and gensets in general, but does has anyone know if this can work for drying?
Is there a way to get rid of the water from the exhaust?
Keep in mind that the genset exhaust stream can be diluted with ambient air in about 50%-50% or 40%-60% so the final temperature may be ~150 oC.
Regards
Dimitris

[Pascal Kirchner]

Hi Dimitris

This is my first post in this forum.

You are welcome.

Has anyone ever tried to use the genset exhaust to dry e.g. woodchips in a dryer(e.g. rotary or linear type)?
According to my calculations, for a woodgas that contains 20% H2 the exhaust will contain ~10% of its mass water.(basic chemistry equations for woodgas burn)
If you use a 100 kw genset running 100% on woodgas you will have about 560-580 kgr/hour of exhaust gas at about 400 oC(turbocharged gas genset).
So, you must anticipate about 56-58 kgr/hour of water in your exhaust.
I am not an expert in engines and gensets in general, but does has anyone know if this can work for drying?
Is there a way to get rid of the water from the exhaust?
Keep in mind that the genset exhaust stream can be diluted with ambient air in about 50%-50% or 40%-60% so the final temperature may be ~150 oC.

I use in my CHP the heat of the exhaust, like almost everyone which is running a CHP.
I use a tube heat exchanger. This is flowed by water. The water warms up and you can use it for any type of heating. To direct link the hot exhaust gases into the chips I would not recommend. Directly behind the exhaust manifold the temperatures are partly above 600 ° C. That would quickly burn your wood chips.
And there are no problems with the water.

regards Pascal

[crimson]

Hi Pascal.
Good to know that you have already used genset heat for drying.
As you can easily understand, if you use a heat exchanger you have already lowered the efficiency of the process...This depends on the efficiency of the tube heat exchanger.
In countries like India, they use the exhausts diluted with ambient air directly into dryers for drying the biomass.
My question is if anyone has done this in European countries and can post some results.
Especially using a woodgas genset.
How much water does your chp exhaust produce per hour?
Have you measured this?
I have calculated the physics for a 500kwe genset as a phychrometric process.
Let me see where I have this and post it tomorrow.
Regards
Dimitris

[Pascal Kirchner]

Hi Dimitris,

Good to know that you have already used genset heat for drying.

Not for drying! I only use the heat for heating my house.

As you can easily understand, if you use a heat exchanger you have already lowered the efficiency of the process...This depends on the efficiency of the tube heat exchanger.
In countries like India, they use the exhausts diluted with ambient air directly into dryers for drying the biomass.

Sure every heat exchanger lower the efficiency. But it brings you safety! Better for drying biomass you could use solar energy. Holzigas is drying his woodchips with warm water produced in summertimes. Here you find his project http://forum.thedrizzler.com/viewtopic.php?f=76&t=182

How much water does your chp exhaust produce per hour?
Have you measured this?

I´m not sure if i understand you right. My CHP is produces 5,6kW electric und 12 kW thermal energy. http://forum.thedrizzler.com/viewtopic. ... =187#p1102 How much water steam is in my exhaust i don´t know.

regards Pascal

[crimson]

Hi Pascal anf thank you for your reply.
Here you can see the theoretical mixing result of 50-50% engine exhaust and ambient air of about 60% relative humidity:

mix 1_1.jpg

And in this photo you can see the result of mixing 33-67% engine exhaust and ambient air of about 60% relative humidity:

mix 2_1.jpg

As you can see the result in the first case is a stream of 217.5 oC with 94.3 g/kgr water content and in the second case a stream of 150 oC with 65.1 g/kgr water content.
Theoretically, the second mix can be used as it is in a dryer(eg rotary) without the need of a gas-to-water heat exchanger...
The problem is that this is only THEORETICALLY...

Best Regards
Dimitris