[Gasification] Drying using a syngas genset exhaust

[Doug Williams]

Hi Shivanand,

You are right to raise these points. 

>shivanand at infiniteenergyindia.com wrote:

> One major issue in using engine cooling air for drying would be the 
> power requirement.  Typically, the engine cooling fan consumed about
> 5% of BHP ( BHP,  not  net power). Assuming similar pressure drop for 
>the dryer system, another 5% of BHP towards power consumption of dryer 
>would be too high a parasitic load.


This would be true if the biomass being dried was high resistance,but
not all driers need the extra fan.
 
Unless the engine generator is being used for base load, many
generators are operating on demand. Listers recommend that in this
situation, the engine operates at about 70% of it's rated electrical
load, leaving 30% to pick up start-up peaks to prevent a drop in
frequency. It's a small price to pay using unused power for adding what
could be a second $$$ making activity drying "stuff" in any rural
community.
 
> Typically the cooling air would be @ 50-55 Deg C ( amx in Indian 
> conditions). This temperature  would be sufficient to dry out the 
> surface moisture. For drying beyond the surface, a higher temperature 
> differential would be required to drive the heat transfer at a 
> reasonable rate so as to make the residence times  reasonable.

While this is true, in practice drying wood blocks in these types of
driers has been very successful allowing more to be dried than consumed
by the gasifier.  Important to watch those parasitic ancillary loads
however.

You might like to check out the Wood chip Bunkers on the Fluidyne
Archive http://www.fluidynenz.250x.com/ The CHP engines were fitted
with water heat exchangers, allowing hot air drawn from the engine
radiator and gasifier room, to be blown over the heating radiators
feeding the drying floors. Lots of waste heat if you can catch it all
(:-)

Doug Williams,
Fluidyne.