International WoodGas Forum

Hello guys,

Can anyone help me? if possible. Im trying to convert a 1 kWe stratified gasifier to drizzler. But im not close to getting the blue/violet flame like other drizzlers. Only orange. Here's the gasifier:





30 cm - distance between the grate and throttle (only charcoal)
10 cm above throttle - only charcoal

after the initial charcoal burning, i put 2-5 cm of biomass.

Biomass:




I've try 30 mbar, 20 mbar, 10 mbar and 5 mbar suction under pressure.

30 mbar: no flame
20 mbar: no flame
10 mbar: orange unstable flame
5 mbar: orange stable flame

Am i doing something wrong? Can someone tell me? i just don't understand!

put more then 10 cm above throttle - only charcoal

30cm should do it and try to hold the hight

The trottle is not realy needed. Just put 10 to 15 cm charcoal on top of the grate. Light it untill red glowing, Let it sinc down and poor some more untill more or less having a stable hot glowing coalbed. Sip in litle by little chips, keep the glowing bed flaming, do not overfeed. DriZzleR feed means drip feed and that is what you must do. drop by drop.
If your charcoal produces gas it will light at first blue and then go out but as soon you but in a little amount of woodchips you produces greyisch smoke and by lighting it you should get a sustainable flare at about half to four minutes time depending on how much gas acumulates in your system.

The unknown factor for me is the scrubber. I do not know of somebody among us that uses a scrubber. Are you sure it eliminates all the charcoaldust? Because charcoaldust is what makes your flare burn redisch. Orange will mean that in your flame is a littel bit yelow burning tar that also might slips trough. Try to put somwhere a piece of ceramic wool to grasp the litleist of particles coal.If you then has a blue flame then your filtering is incomplete and you need to put somewhere an end filter stage.

So either you have too much woodchips and you do not DriZzle and run too cold or somewhat the scrubber is the cause. Just speculating because it is always difficult to judge from distance.
still
Luk

Thanks for the advice, Jan! i will try it.

hum.. i forgot to mentioned that i have some troubles with the biomass/charcoal flow through the throttle even using a manual pyrotouch. I think its become of because the size of the charcoal and biomass is too big for the throttle diameter. Does it explain the unstable flame? Should i get charcoal/biomass with lower dimensions?? THANK YOU!

Luk,

the scrubber is fine . There is no dust in the gas flame, only tar. Soon i will make a video, using your and Jan advices, lets see what i will get. But no throttle, 30 mbar? 20 mbar? 15 cm charcoal? THANK YOU, LUK!

Continuing... Today i found my throttle almost melted inside the reactor, the flat plate became a curved plate . Maybe it explain why my test failed yesterday (no blue flame achievements). So, i tried it again, but this time, without throttle or restrictions. Now i get a sustainable orange flame . Take a look:





First, i put 20-25 cm of charcoal in the reactor and lit. I've wait a complete charcoal glowing surface, this takes 2-4 min and then did try to light the gas, no success. But, when i threw a full hand of biomass, the gas starts burn. The color did'nt change, only this orange. If i threw a little amount less of biomass, the flame turns off, like on the end of first video.

Under pressure: 30 mbar - no flame.
Under pressure: 20 mbar - sustanable flame
Fabric filter: on
No restrictions - 150 mm reactor diameter.
Wood chips

Andre,

It seems you made some progression already. As I said trottle plate not needed. Then the isue about your flare going out. DriZzling is a "Knack" you have to find the sweet spot between not overfeeding and not underfeeding. DriZzling is just in time feeding. By doing it by hand you first have to find a ritm. Then time this ritm interval and then always trow at the same interval the same amount of chips. Later with a pyrotouch the feeding will be decided by the feeler.
And about this flare I would say it is not orange, more violet and purperisch so that is a good sign. There is not much tar in it as far I can judge by a video. Why it is not completely clear blue as my filtered flare allways is I have no clue. Maybe your waterfilter has to do with it. As I said before I have no experience with that sort of filtering.
Keep on working.

Luk

Andre,

Just something came to my mind after studying your scheme again. It seems you replenisch the water of your scrubber. Can it be that after a while this water becomes saturated with coal dust and some of it goes trough with your wet gas?
Just guesing.

Luk

Luk, good question .

I will examine it and bring you a answer. But something that i dont understand is why cant i get a flamable gas only with charcoal?
back to work now...

Andre,

That is an answer you should seek with the charcoal gasifier builders. It has to to with the chemical reactions (for instance the watershift reaction) that are different in both type of gasifiers. To compensate for some of the limits of only charcoal gasifiers those people inject steam or experiment with water and oil drip.

Luk