Hi Koen
do you mean that the gas coming out of a “Riche” still contains tar and can not be used in an engine ?
1 Like
Hi Thiery,
the words to look for “carbonic acid” in one way and insoluble tar’s the other way…
if however a glowing charbed at high temperature could be created at the bottom, beforehand, and maintained during the batch process, then all tar would be cracked as would the carbonic acids.
That temperature would be above 1300ºC
ad some oxygen in the carbon in the Riche retort to compensate the endothermic reaction from reducing the tar fraction does the trick… 
3 Likes
Might explain the strange experiments i perform ? anyone ?
4 Likes
The retort is supposed to be preloaded with some charcoal in the bottom and brought up to temp, then wood was added. But it seems it was a continuous feed system of sorts. Every so often the charcoal at the bottom was removed and fresh wood added at the top. Don’t know if I’d want to be the guy with that job. Thank goodness for modern automation.
You actually make a similar argument about temperature as someone quoted by the author of one of the books. And yet the Riche’ Retort apparently worked. From my own reading about autothermal reforming and gasification, 800-900° C seems to be just fine for the temperature to crack the tars. Not trying to argue. I am a noob, just saying the design and operation was already proven a long time ago.
But who knows. The definition of clean gas could have been a little more loose back then. Maybe 1300°C is necessary to clean it to today’s standards.
Think you could share the results of some of your tests with the device you made? If you can’t because it’s a trade secret, I understand.
3 Likes
1500 2000 f degree seems too work just fine, a well design hearth too match too motor size, wood size, dry the wood enough, and choke sized. and as you said a good size charbed, no tar cracker needed. oh and recycle the heat around burn box and or heat exchangers.
3 Likes
Yup, i am reading the book on Google , thanks for pointing out, stating 1652ºf, what equals 900ºC.
The "cherry red " does cause some misunderstanding ( for me) leading to confusion about the actual temperature ( colors are more subjective )
Riche also injected air when there was Tar present in excess.
The Charcoal (carbon ) , if the retort system is well designed, is consumed in the process of reduction. ( only ashes out ) or leftovers are sorted out to reuse…
Depending the temperature ranges working in, the glowing carbon strips the O’s from the nasty’s and form CO ( nuttshell explanation )
If you check this clip, then you see the reduction of the CO2 starting at a certain temperature and nearing complete at 1250ºC ( input gas was 100 % CO2 ) at the end i did have the insert probes molten (stainless steel) as well the Kanthal heating elements…
3 Likes
Thats cool hot research equipment you have there. how well do bambo priolisize in the wood gasifoer mode. would you say that bambo is harder too drive on than wood in a wood gas truck system like WK trucks. ?? Thanks
2 Likes