Torrefaction, haven't heard much about it lately

I just spent 3 days running around walking into walls trying to recall the term “torrefaction” and exactly what it meant and why I had been interested in knowing that stuff at all… Two or three years ago it seemed to be a fairly popular subject around woodgassers, but not recently, to my knowledge. I bring it up for a couple of reasons:
First, because when I finish a woodgas run and shut down my gasifier (JXQ-10) I end up with about half charcoal and about half “charred wood” chips. And I couldn’t remember what the difference was. Now I have found some references again, so I can say (right or wrong) that the partially charred wood chips have been torrefied. There. Now I can sleep again and my forehead can heal.

Secondly, I know that many of you are “Charcoal” guys and I wonder if you make the distinction between charcoal and torrefied wood when you prepare your fuel.

to get a better understanding of “torrefaction” than I can give,
Torrefaction or
“Stages of Pyrolysis”. About The fourth link down on this search yields a pdf file that I can’t seem to get a link to that is less than 10,000 characters long, but it does a real good job of explaining where torrefaction fits. The link is labeled “Pyrolysis and Torrefaction of Biomass”

Pete Stanaitis

From what I remember having torriefied wood to start would be more beneficial than raw wood. I was told it wouldn’t be cost effective because of the process needed and the length of time. I am still convinced we can utilize the heat from either right out of the gasifier or after the heat exchanger being that the desired temp is between 300-600F . I have other hurdles to overcome before I can experiment with torrefaction but it is on my list. I think it would be a great prestep prior to putting the wood in the hopper. It would also seal the wood and prevent it from asborbing moisture.

Someone should get some pellets and test!

A chemist buddy did some research on torrefaction. He was able to get 12,500 to 13,000 btu/pound, over a 50% increase over wood. Also, torrefied wood is very moisture resistant, unlike wood pellets. As a result, it flows through the gasifier much smoother. Not nearly as much bridging. I feel this is how Europeans handled running with gasifiers. They controlled the charcoal/coal market like we control gasoline quality today.

My friend would screen his. The under-sized char went to the garden or compost pile. The larger chunks were fuel.

**spaco,**as for torrefaction, it is also a method to produce fuel, which is based on the
thermochemical processing of biomass. In this case, torrefaction is used to
make torrefied wood pellets (so called biocoal) – relatively new kind of
biomass fuel.
As you may know, there is another popular type biomass fuel. This is about
wood pellets, which are considered to be eco-friendly. However, torrefied
pellets appeared to be even cleaner and more efficient. This type of fuel has a
number of advantages in comparison with wood pellets, which the article describes:
First of all, this is about torrefied biomass similarity to coal, which means that
it does not require any special equipment to be combusted. Thus, you can use
it in your home without applying any additional devices. The second is that
torrefied pellets produce more energy in comparison with wood pellets.
In addition, if you are interested in torrefaction technology, you can find more
information in article mentioned.