Hello Tone,
You should wait on this idea until you have ran a few hundreds of kilo’s of wood through your system.
Good operating raw wood system will assume an upper hopper thick coating:
page scroll down for the open hopper down picture.
Ha! I am not picking on Joni. I’ve just kept his earmarked.
All others with worked systems do this too. Why many insist on black painting the outsides of theirs to not have to continually clean the black drool streaks.
You will have to position your tubes inlets to not quickly pick up tars smoke and build up layers clog.
Regards
Steve Unruh
Hi Steve, I definitely plan to operate the system for at least a month in its original state, and then I will try out new ideas. However, this is a very simple and quick procedure, I pull out the core, mount the venturi nozzles, and from the back there is a hollow ring for the supply of steam and gases from the top, where they will reach three 1/2 "pipes. The system has been operating for about 10 hours so far and I notice a very thin layer of tar on the wall, obviously due to the hot atmosphere and the heated wall it does not condense on the housing.
Tone the tar coating is good. It will prevent upper system acid corrosions.
Upper systems (above the nozzles) will become ~2 points to acidic.
Downstream system (after the restriction plate/grate) will become ~2 points beyond 7.5 neutral ph.
S.U.
Hi Tone, I like the idea. Kristijan and I had a discussion on this a couple of years ago. A venturi nozzles sucking from the top of the hopper. The problem with the water vapor is it carries tar juices that could plug up the venturi system. Look at the inside of the hopper walls sticky black tar, inside the nozzles would be the same. Now if you could run this vapor down the sides of the hopper and some how push or pump it out through separate pipelines just above the nozzles where it is the hottest. That would work. Maybe @KristijanL can find some of his drawings on this idea. It is a great idea.
How about a nozzle down the middle of the firetube with the ones all around to cove this center area.
Bob
Yes Bob l remembered that imidiatly. There shuld be drawings of this somewhere here but lost in the sea of posts. But no need to search for it, my drawing was preety much identical to what Tone drew. Never got to building it thugh…
Tar plugging, lts hard to say. Tone runs a hot hopper and the nozzles shuld be wery hot at this point. Tar shuldnt cling to them. But the question is what happens in contact with cold air…
Yes Kristijan, when everything is hot there will be no problem but when the gasifer is cold that is when tars form and can get real sticky in side the nozzles and plug things up. Thanks for your response on this.
Bob
If it was a central nozzle centered in the hopper to feed the water, I would think tar may stick to the outside of the pipe. Then under the next fire and heat cycle the tar would loosen and drip, straight into the hottest part of the fire lobe? Granted it would only feed that tar that was stuck to the pipe that would be a good tar cracking system and more power made, I think?
I think your ideas exchanging came to the spot of “tar recycling gasifier”. One of proven concepts is mentioned in the gasification bible shared on this site:
No matter of particular construction, my humble opinion is, that inner tube sucking the vapours from the top of hopper is the best approach.
First, the tube is wide enough to prevent clogging.
Second, it is easily removable fo cleaning.
Third, it is heated by the surrounding flames and vapours which also prevents clogging with tar.
If air used for venturi suction at the top is preheated by output gas, then tar vapours will not condense at all. Heated inlet air also bring more energy into active zone, what may help to break more water comming along with tars from the top of hopper. And this is what all gasmen are seeking, isn’t it, ya?
Thank you Kamil, I have never seen this drawing before very interesting. It would work in a WK Gasifier unit. Just place it above the other nozzle just out side of the metal melting charcoal zone. It could hang in the hopper from a chain so the whole nozzle could move back and forth alittle. Use a slyclone hose for intake air. It would keep the wood bridging down in the hopper.
Bob
One of the guys here in Sweden (Gengas Werner), has done something that reduces the consumption of wood by about 1/4, and gets better gas, (more hydrogen) now I do not understand it, but it might work.
He has a wire mesh on outgoing gas from the cyclone that catches carbon particles and burns up the oxygen, which means that the water gas is not regenerated but the amount of hydrogen increases. @KristijanL , do you understand how it works?
Unfortunaly not. Talked to Tone the other day, l presented him a similar idea in wich one wuld pass hot gas trugh a catalyst (iron oxide pellets) in order to enrich the gas with methane, but the process looses energy as its exothermic and the side products are CO2 and water. I dubt that route is worth the while.
The process might be similar. Are you sure he has the wire mesh after the cyclone? Shuld be too cool down there for any reaction to happen…
So the peaces that the cyclone is ment to catch anyways? Ok. Well then lm eager to learn more. Shuldnt be possible from phisic point of wiew. Not enaugh energy as the water gas reaction is highly endothermic. Unless he injects some oxigen with the gas, wich defeats the purpose…
But thats the job of the reduction zone. Wich this is too… But it requires vast amounts of energy and there shuld only be trace amounts of free oxigen in the gas of a well designed gasifier. It wuld make sence to me if he tryed to “crack” the remaining water in the gas via water gas reaction but here lm lost
