Still: Be sure of thread thickness, opening size and ss material,
roll width and length, MOQ = minimum order quantity!
Remember: Heat resisting quality!
Don’t do shortcuts! Go exclusively through PAYPAL!
I seem to have lapped to answer on Vesa Mikkonen’s system as a whole:
I am going back to the fundamental (starting) question:
How do you prefer to handle 8 gallons (~30liters) of soot?
Is it a good idea to blast all that soot directly into a large fine-filter,
and then follow up with washing, cooling and drying?
My idea is to do a daily 2 – 3 minute cyclone-pot emptying and
removing 90 – 95% of the soot, thereby postponing
the filter handling with a considerable count of weeks.
Who likes what?
In the proposed 3 – component system (including gasifier) the big fine-filter is totally scrapped,
a paper filter handles dry warm gas after the cyclone and washing – cooling – re-heating.
Washing by a flap–flap–flapping cloth on the water surface under the cooler. The gas streaming between the surface and the wet flapping cloth. No significant pressure drop from floating the wet flapping cloth on the water surface.
Child’s play with a towel at the water-edge, just remembering…
From one end of the condense tank to the opposite end.
The gas inlet has to be near the top, and the cloth has to start
at the top, and then fast going down to mid height (rails) on both sides.
The cloth (canvas) has to have very liberal slack to fully reach both the bottom
and the top along the length of the condense tank.
The gas-inlet better be turned downward, to avoid “burning” an eventually dry cloth.
Heat resistant cloth preferred.
In my gasifiers, we use charcoal is first filter
This makes me think: why trow away the charcoal from the ashdump ? why not build a first media filter with it ? After use , this material can be mixed with your wood into your gasifier.
The charcoal from the gasifier is “activated” and a good adsorbent for tar and acids.
Ha, funy you mention charcoal as filter. I am thinking to make a hidroponic sistem with charcoal to be the bed media for denitrification bacteria to clean the fish water. Seems the black gold is endlessly useable
As long as char remains dry it shuld collect tar. Once wet, the pores will plug with water/soot and close for tar absorbtion. Hard to acheave with woodgas. But it wuld still work as a wet hayfilter!
Hi!
13.2.2018
Those who have a gasifier without a dangling grate, but a reasonably effective cyclone, are observing that the collected soot- and flyash-volume is far grater than the cleaned out restchar volume.
This ratio, combined with a double charcoal siftning effort is hardly attractive. First sifting the outrakes from the gasifier, and then once again sifting the charcoal filter contents…
Combine these factors for the function of a massfilter filled with on board made carcoal, and figure out where it leads. At least you need extra charcoal for the filter.
Further more: A cyclone cathes on a daily bases 90 – 95% of the soot and ash stream, prolonging the cleaning intervals of the second stage of filters…
On wood gasifiers, maybe use charcoal to build a last media filter, just before the safety filter to catch any tiny nasties that worm their way through the system?
Charcoal granules were recommended for primary filters on charcoal gasifiers that used anthracite. Another charcoal gasifier used a wide bed of charcoal granules over a cloth drum. The surface could be raked periodically to break up the caked surface.
In general, surface filters as cloth, fine mesh or felt are working better than volume filters filled with cork, char, wood shavings or something similar. Volume filters can’t separate especially the fine particles as effectively. And they are often bulky (not that much a problem on a pick-up).
This was already known in WW2, but a lack of a suitable hot filtering cloth prevented the widespread use. They mostly used cotton, which was OK for charcoal gas with a low dew point and thus lower possible dry filtering temps, but not for the moist woodgas.
Today, there are much better filter cloths availlable.
Only disadvantage: They cost more money, as you have to buy the special filter cloth.
Back in '08 and '09, I spent a lot of time around the US Forestry Service’s BioMax 25 by Community Power. They use bag filters sewn by the wives of some of the workers. Essentially, it looked like a pillow case of white filter material. Weights are sewn into the closed end. The bag filter sits inside a 30 gallon or 55 gallon drum, as I recall. The engine vacuum and the flow of gas causes the bags to billow up. They had three or four bag filters in a line. When one bag gets clogged up, the operator switches from one drum to the other. Those weights in one end now drop down, shaking out the particulates.
The soot and particulate accumulated in a sealed base at the bottom of the series of drums. A screw auger pulled the particulates out into a drum for disposal or recycling as a soil amendment. I was surprised at how it looked like rich carbon, just like a black laser printer toner contents. This was almost a decade ago so my memories may be off a little.
They also have rolls and some bigger sheets of 25, 85, 100, and 125 micron. They mentioned 125 micron as a pollen sifter… would have to try it out. Ebay seller with a good rating.
What ever we use i need one for sure and i think as max has been saying large filter, i am thinking on two big flat filter too fit beside the cooling racks, with able too get apart for cleaning or inspection, this way would have at leaste a few hundred miles before car washcor bucket funnel cleaning with a few pipe caps. The big cean out door would be angle iron 1/4 too 3/8"and siliconed till anual inspection check. Something around 2 by 3 feet or big as fits beside cooling rack.??? Is this a good idea? Or is maltable towel filters in paralelle be better.??? PS Whops i am talking cold filtering.
Inches and inches; small patches, handketrchiefs, towels as maximum!
We need yards and meters on a roll! Dont look at less than 30m!
And with openings no bigger than 25 microns, 15 preferred!
The opening is the important factor, not the “thread”!
I agree with Max. I think 25 micron is minimum. Problem with hot filters and woodgas soot is vibration. The idea here is to make a cake of soot on the mesh that does the actual fine filtering. Now, with the mesh too large, and the vibration, the soot cake gets “ground” trugh it.
Thats my experiances with to loose fibreglass cloth, l figure its the same with ss mesh.
