Between my cyclone and my filter, I have a 2 "pipe in aluminum.
This can pose a problem there?
With wood charcoal I can’t see why it would be a problem. Just inspect it from time to time. Maybe others have experience with aluminum pipe. It does conduct heat well.
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I’ve used an aluminum lid on my filter for a few years and it’s holding up fine with woodgas. I’m trying it on the cooling rails next. Like Jeff said just inspect regularly.
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Thank you for the information, Jeff, Marvin.
You eliminate a doubt in my mind
Thierry
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Hi, Thierry!
17.3.2016
The safe temperature area is between dew point and meltingpoint.
If condensing happens, water soluable components like CO2 and already made accidic gases can corrode aluminium.
Max
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Some melting ponits to decide in the future.
The first are in centigrades, the second ones are in farenheit.
Metal Melting Point
(oC) (oF)
Admiralty Brass 900 - 940 1650 - 1720
Aluminum 660 1220
Aluminum Alloy 463 - 671 865 - 1240
Aluminum Bronze 1027 - 1038 1881 - 1900
Antimony 630 1170
Babbitt 249 480
Beryllium 1285 2345
Beryllium Copper 865 - 955 1587 - 1750
Bismuth 271.4 520.5
Brass, Red 1000 1832
Brass, Yellow 930 1710
Cadmium 321 610
Chromium 1860 3380
Cobalt 1495 2723
Copper 1084 1983
Cupronickel 1170 - 1240 2140 - 2260
Gold, 24K Pure 1063 1945
Hastelloy C 1320 - 1350 2410 - 2460
Inconel 1390 - 1425 2540 - 2600
Incoloy 1390 - 1425 2540 - 2600
Iridium 2450 4440
Iron, Wrought 1482 - 1593 2700 - 2900
Iron, Gray Cast 1127 - 1204 2060 - 2200
Iron, Ductile 1149 2100
Lead 327.5 621
Magnesium 650 1200
Magnesium Alloy 349 - 649 660 - 1200
Manganese 1244 2271
Manganese bronze 865 - 890 1590 - 1630
Mercury -38.86 -37.95
Molybdenum 2620 4750
Monel 1300 - 1350 2370 - 2460
Nickel 1453 2647
Niobium (Columbium) 2470 4473
Osmium 3025 5477
Palladium 1555 2831
Phosphorus 44 111
Platinum 1770 3220
Plutonium 640 1180
Potassium 63.3 146
Red Brass 990 - 1025 1810 - 1880
Rhenium 3186 5767
Rhodium 1965 3569
Ruthenium 2482 4500
Selenium 217 423
Silicon 1411 2572
Silver, Coin 879 1615
Silver, Pure 961 1761
Silver, Sterling 893 1640
Sodium 97.83 208
Steel, Carbon 1425 - 1540 2600 - 2800
Steel, Stainless 1510 2750
Tantalum 2980 5400
Thorium 1750 3180
Tin 232 449.4
Titanium 1670 3040
Tungsten 3400 6150
Uranium 1132 2070
Vanadium 1900 3450
Yellow Brass 905 - 932 1660 - 1710
Zinc 419.5 787
Zirconium 1854 3369
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Interesting to note that carbon steel has a higher melting temp than stainless. Why are we using stainless in the extreme regions like the grate, and the simple fire nozzles?
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Great list! Keep in mind that for tuyeres/nozzles we are not dealing with melting, but with catastrophic oxidation which severely corrodes metal at much lower than melting temps.
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Is there such a thing as a chart of oxidation rates of various common metals? It would be interesting to compare oxidation rate to melting temp in choosing.
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Ok guys, good morning!
You made me fetch and read more than expected. I found 2 papers that can help answer your question. These are a bit long, but if you read the resume you get the idea. In small words, the condition is that it depends on the alloys, temperature and oxigen concentration; this mens that in a poor environment as in the hearth of the reactor (very low oxigen), the rate of oxidation is low. The presence of tars over the metal should contribute even more to lower the rate of oxidation (I think).
Ups…I cant upload the PDF papers. If smeone give me an idea of how to, I’ll apreciate. Sorry
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Can you just link to them? We don’t have uploads for files, just pictures.
Some food for thought.
Many people here have said they can produce charcoal of high enough quality to make it conductive.
This would indicated graphite production…
Can a gasifire itself produce graphite dust?
All dry lubricants with a Milspec rating have no graphite in them because this material is known to be a catalyst for aluminum corrosion.
Add acid and water and the potential for graphite in the slip char and I think its worth further investigation of aluminum is a suitable material for a gasifier cooling circuit…
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Didn’t someone try sticking a piece aluminum (possibly a chunk of window frame) in their cooling rack for a while to see how it faired a while back? I recall it came out quite corroded, but it might have been a cheap alloy. That said, would one want to use better, more expensive alloys for something like a cooling rack?
@Wallace I believe graphite has to form under considerable pressure, basically cold diamonds.
I installed an Aluminum hopper fill lid about a year ago, and it seems to be doing very well. Only time will tell how long it will last. SS is about the only thing that will not corrode in our harsh environments. I have SS nozzles hoping they could be replaced if necessary. Again, time will tell. Last month I replaced 24" sections of the cooling rails with Aluminum handrail pipe for added condensation, and temp reduction.
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That said, aren’t hopper (before reaction) condensate and cooler (after reaction) condensate opposite pH? I believe hopper is more acidic and cooler is more alkaline. I thought aluminum handled alkaline better than acid though, so you should be ok.
Acids and bases are both hard on aluminum.
Stronger the solution the more violent the reaction
Aluminum is actually a very reactive metal, but it has a very strong bond to the oxide layer that forms on its surface when exposed to air.
This is why you can not easily solder it.
Anything you put on it to break the oxide layer will eat the metal underneath.
Aluminum is aggressively able to steal oxygen from other metals like iron that have both a weaker bond and permeable oxide layer.
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At the business end of the tuyere in a charcoal gasser, there is both high temp and high oxygen. Oxygen is pouring over the hot lip of the nozzle before it combines with the fuel.
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Hi,
l an thinking to make a heat exchanger with flexible aluminium tube. The metal is very thin (0,15mm) but has a lot of surface area. A 3m peace l plan to use has about 1,5m2. The issue is heat and alkaline ash. Thy are rated for up to 300°c.
Any thods?
Hi Kristijan, I am going to test aluminum tubing on my cooling rack on the charcoal gasifier. I will let you know what happens with any heat and alkaline ash problems.
Bob
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I would like too test aluminum on the Wayne Keith Type heat exchanger too see how it holds up, maybe after a pipe cyclone heat exchanger too rid the heat the aluinum caint handle,should bring back more heat yet,than steel drop box heat exchanger…
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