Hi Don.
I only shake my grate when it needs it. I may go through several hoppers of fuel and will shake it while refueling with a T bar .
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Hi Don, I have one on my Gasifer, but I donāt seem to ever need to use it. Before start ups I check my grate to see how tight it is. Poking a few holes down there to check it through the grate. If it is really tight I have my manual T- handle shaker tube. I have only used this a few times. The poking with the rod before start ups seems to do the trick.
Bob
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Grate shaker??? No grate - no shaker.
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You need a gasifer shaker. Find the roughest bumpy road you can fine and drive over it at high speeds.
Bob
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Hi, Tone!
13.2.2021
It is a good effort to utilize the heat in the outgoing gas from the gasifier to preheat the intake air for energy recycling!
An alternative or complement to this system is to let the hot gases after exiting the hearth go up in the middle of the silo in a full silo-diameter broad āplankā about 1" thick.
The plank has two ālegsā, one on each side of the silo ātrumpetā, where the wood is narrowed into the hearth.
The legs are joined to the full breath plank a bit over this funnel, so they will not disturb the wood flow down into the funnel and hearth.
In the silo upper end, the gas is taken out by a horizontal tube screwed into the plank-top.
The plank has a top-lid from which it can be cleaned downwards, and the soot will fall down into the low down ash bunker, passing outside the hearth.
At the hearth-height, the outer āskinā is a double mantel for
preheating the primary air, and insulated outward.
This way no heat is lost to the outside, as no part of it is exposed to outside cooling!
The silo can still have condense cooling, either in an outside cooler, or using the silo wall with an internal separation cylinder in a traditional silo condensing fashion.
Heating the wood directly brings more energy recovery, than
preheating the intake primary air.
But both are doneā¦
Max
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Thank you Max, I am also of your opinion, to overheat the wood and thus dry it as much as possible, and I think that the supply air will be preheated enough in the supply pipe, which will be cooled so that it does not deform.
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Efforts have been made to decrease these losses through various designs; e.g., through insulation of the fuel storage to prevent heat radiation from the outside walls of the generator, through leading the hot gas up around the fuel storage between 118
the outer and inner mantles, through preheating the primary air, etc. With the exception of the last method, however, these measures do not appear to be useful. The reaction ability of charcoal is impaired by very high charring temperature and long charring time in the generator, which may be observed, for instance, in up-draft generators. As men-tioned in the preceding section, it may be more advantageous to promote condensation and dehumidification through extreme cooling of the walls of the fuel storage.
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[quote=āgasman, post:98, topic:5240ā]
Hi, Tone!
13.2.2021
It is a good effort to utelize the heat in the outgoing gas from the gasifier to preheat the intake air for energy recycling!
Ok , for me a lot is new!
wood ore charcoal gasifier can work without preheat the intake air?
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Yes they can. But preheating air highers efficiancy and aids to whats called the flywheel effecĆ¾. Making constant quality gas when engine demand shifts.
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Hi, Haapio!
15.2.2021
SiittƤ vaan! Suomen Ekoautoilijat r/y ! (just for reference)
It is still more efficient to deliver the exiting gas heat to the wood in the silo. (indirectly of course)
And complementing condensation at the periphery. In a doubble mantel or externally.
This contributes to better drying of the wood; the internally bound water in wood consumes a lot of PROCESS HEAT, which is lost from the gasification and reduction processes.
So, the drier wood we present to the gasification and especially to the reduction process, the more completion the reduction process will reach.
Max
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Hi, Tone!
16.2.2021
Heat up, gas out!
Max
Hi, Haapio!
17.2.2021
Bolts can be used as nozzles, but size and length and count are naturally dependent of the planned hearh-size.
Gasifier planning usually goes ābackwardā starting from the planned or needed gas consumption.
Do you need a formula for the consumption of a motor at a specific displacement volume (cylinder volume) and rpm?
The practical design varies with the planned use; for example cars, boats, tractors, stationery designs have their own solutionsā¦
Switzerland had charcoal-gas driven surveillant planesā¦
Max
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Good Morning Tone,
I have studied much your charging regulation system.
Three phase AC.
I can follow this as I was an automotive electrical specialists for many years. ALL, I ever worked with (except one old obscure) were at their hearts 3 phase AC also. With a DC made variable field.
Here; US and Canada, we use at the personal consumer level only single phase AC.
Sigh. It is weird. An relatively poor to weld with versus three phase.
Now onto your gasifier āPropertiesā topic.
I am now realizing doing trial simulations just how important in a downdraft wood gasifier the above jets ACTUAL VOLUME is to the; below the jets EFFECTIVE VOMUME.
āEffectiveā below the jets is the actual working volume AFTER the char-ash cone and coating ash crust have formed.
Joni last pictured this the best on his GJ 9.0 beginnings topic pictures set. Viewing down only removing the loose center materials.
In all of the publications these volumes proportions are inferred by the nozzle ring dimensions; the base recommended diameters and height settings.
And taking wood gasifier systems with known good performances; assuming they must be within a range of best-use; then a mathematical chart of volume ratios could be made up.
For woodgasifers I can now state why I see this volumes concept works.
As the wood burns down to wood charcoal it shrinks in volume.
And to keep a tight bed of hot wood charcoal that ALL gases must pass through formed . . . then the effective materials holding volume must shrink proportionally also.
Most systems are making the below the jets effective after ash-crust build up TOO SMALL.
And the straight tube walls systems this below the jets is TOO LARGE versus the raw wood volume possible above.
Regards
Steve unruh
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Hi, Steve!
8.3.2021
A ārecordā Volvo with a 2,4 L motor made 130 km/h on āopen roadsā during its travel from Finlands southern tip to Nordcap in Norway. Within 24 hours.
Its cut cone, from nozzletips to restriction volume is
7% of the āsekundenverbrauchā, as the Germans say.
And half a cigarett pak fuel size.
Why is nobody else taking the ratio of the cut conical hearth volume to consumption per second into account when designing the hearth?
Max
9 Likes
Good point Max
Excellent document with tables for calculating hearth size and load here
http://www.driveonwood.com/library/fao-72/
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Hi Max,
Secundenverbrauch translates to Second Consumption/expenditure/drain
So in converting woodfuel as a solid as completely as possible into fuel gases: the the second major phase of physical form changing.
Joniās; WayneKās a few other system place the actual restriction very low down with ~80% of the made wood char and gaseous reduction above their restrictions. KristijanL was the 1st to verbalize recognize this.
My active materials guess volumes ratio only works by adding in all active char areas above, and below, the restriction to the char being grate held volumes.
Something with your vertical-bar, thermal/char-saver grate tubs you should minds-eye see also, maybeā¦
So from a confusing four zones concept; to a practical in-use, functional two zone concept.
Viewing as such may help others not get lost in the upper systems idealizing before they ever make it down to the lower system needs.
Regards
SteveU.
1 Like
Hi, Wallace!
9.3.2021
Excellent for standard builders.
Typical; no explanation of HOW the presented measures have come about!
Just measure tables, in Blanco!
Binding to flow makes sense.
Max
High, Steve!
9.3.2021
The nozzles to restriction cut cone process volume is optimized to deliver a white glowing optimally (tar) cracked raw gas with only a small part of unbound oxygen remaining.
Above it, heat is spent to boil off water first, then tar from the wood.
Assisting in this, a plank preheating the wood with the āfreeā exiting gas-heat is helpful.
And peripheral or external condensation.
The main aim is to deliver the hottest possible and tar-free
low-oxygen gas swiftly into the reduction part.
The better this part functions, the better the reduction comes to grip with its task.
To dimension, the oxidation zone (cut cone) as a percentage part of the gas consumed per second has been successful in applied cases.
From Dutch Johns, small āgrasshoppersā driven on part load to WWII heavy trucks in Sweden and elsewhere.
These calculations are the easiest to do for full load conditions.
Dutch John had the best performance with 4% oxidation volume (part-load). For small āgrasshoppersā.
The record Volvo was specially designed for the record trip, but it has functioned well also in normal traffic. 7%
Fuel size: Half a cigarette pack.
For big trucks 9 ā 11%.
Fuel size: Bear can.
I think we have a design criterium with some good resultsā¦
To handle cut cone properties, try this when you draw: Conical Frustum Calculator
Max
1 Like
I will make a $100 donation to the first go fund me guy that goes to Bonneville and sets a woodgas land speed record to exceed 100mph.
Wayne did 84mph in 2011ā¦
Then you will see properties of a good wood gasifier.
Nothing proves concepts like competition
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