[Gasification] If connecting a gasifier to a micro CHP unit isnot feasible what other options are there?

[doug.williams]

Ian,

You might spend some time reading the Gasification Archives to see what has 
been done already, but here are a few answers to get you going.

> My question on that topic would be what waste products (gases etc) would
> come out of the exhaust if the material combusted were rice husks?

The exhaust gas from an engine running on producer gas is mainly CO2, some 
CO, water vapour, and Nitrogen. Gasifiers operating with rice husks are 
notorious tar makers, so you could expect a higher than normal CO content.

The
> reason I say rice husks is that in many places in Asia, rice husks are a
> waste product dumped by the side of the road or burned in the open air
> causing respiratory problems downwind). I'm very interested in the whole
> zero emissions aspect of how to use waste products at each stage of a 
> system
> that would have a gasifier as it's central unit; much like the Kalundborg
> Industrial Ecology system in Denmark has a whole bunch of industries 
> feeding
> off the waste products of the power station there.

Rice husks are used for a wide variety of heating applications, and their 
ash waste stream is used for refractory, and cement additive to make a 
highly acid resistant concrete, just two applications that come to mind. 
Rice husks do not gasify in a way to make clean producer gas, so limit their 
use to process heating, at least on a small scale.

> Since Doug writes that marrying a Stirling Engine to a Gasifier is not an
> easy marriage of technology to organize, might I ask both of you what in
> your opinion would be the best way to harness this heat prior to its use 
> in
> a conventional engine?

In the very first instance, You cannot take the heat away from the casing of 
a gasifier without disturbing the endothermic heat consumption. The only 
heat available, is contained in the hot dusty gas once it leaves the bottom 
of the char bed. The temperature will depend on the type of gasification 
process, but it is usually soaked up using air, or water heat exchangers. 
You could of course use oil instead, but it depends on what you want to do 
with the heat.


> Also who in your opinion would be the best company to
> approach for such a project.

>From what you have said about your own lack knowledge,  I would suggest you 
are leaving yourself open to loosing your shirt. All you have to do is wave 
your cash, and you will be inundated with offers of wondrous technology.

>The reason I ask is that Whispertech seem to be
> operating at full capacity to fill orders in Europe, so I don't imagine 
> they
> would be interested.

If you bring a lot of money with your ambitions, you can possibly do 
something, but ideals and ambitions on their own are useless. Companies do 
not in general, have people able to work on developing a new process outside 
of their own expertise, or product range, particularly if they have cornered 
a market sector like WhisperTech.

> I realize that this is going off the gasifier topic, since it's more like
> industrial ecology, but Bof and I seem to be interested in the same kind 
> of
> thing: using the waste heat to generate additional value somehow; Bof's
> looking at using the waste heat to assist in the production of Ethanol 
> which
> would mean two for the price of one; gas and ethanol. Here's a thought, 
> and
> excuse me if it's dumb since I'm not an engineer, but could the central
> chamber be married to a steam engine? The chamber is really a furnace so
> what would be the effect of wrapping a steam boiler around it? I'm trying 
> to
> figure out how to make a gasifier multifunctional in a '1 raw material in
> more than one product out' fashion.

I admire enthusiastic thought, but why are you not better informed at the 
huge body of work that so many differing technologies cover in the area of 
your interest?
Without engineering knowledge, you are obviously wasting talent covering so 
much old ground. Utilising waste heat is a noble pursuit (in a cold 
climate), but only a fraction of use compared to creating electricity in a 
rural situation that cannot convert it's local resources into a saleable 
product. Have you considered the impact of creating a micro economic 
activity around a gasifier installation in a rural community? It's true that 
you can do almost anything you can imagine as joint processes, but in 
practice not usually possible due to location, climate, market need, 
regulations, etc. In gasification, we use the waste heat to dry the incoming 
fuel, especially in the wet season.

This is all I can offer myself at this point in time, so hope it covers some 
of your thoughts.

Doug Williams,
Fluidyne Gasification.




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