Burning tires presents a unique problem......... The heat of the
fire causes gassification of the rubber at a far faster rate than you
can supply oxygen to burn the gasses. Supply oxygen (air), and the rate
or gassification simply increases as the fire gets hotter....... the
result is incomplete combustion and lots of smoke as we all know from
having seen rubber burn
The solution is fairly simple......... You burn in two stages.
The first stage produces heat and gasses (smoke), and the second stage
burns those gasses far enough away from the first stage that it doesn't
contribute to the gassification process.
A third and very viable alternative is to break down the tires with
heat, but to condense the condensible gasses into a liquid to be burned
later. Those gasses that will not condense are simply fed into the fuel
stream that is being used to break down the rubber.
This allows a very controllable combustion when you are using the
heat for something like your metal casting, and allows you to batch
process the rubber which for obvious reasons is preferable to firing up
a rubber burner every time you need the heat.
The non-consumable materials in tires is significant....... A lot
of steel belting mainly.
The logical way to "render" tires for combustion is with a
hydraulic shear. Rotating blades don't work well due to the heat
created. Sharp blades work very well.
Interestingly, I once ran a Ford V8 on rubber vapor for about 15
minutes just to prove that it could be done. I built a small chamber
from a piece of pipe with one end welded in, and one that bolted on, and
put cut up inner tubes in the chamber. One end had a pipe fitting and
short steel line with a valve on the end. I heated the chamber with a
weed burner to get the rubber to vaporize, and once I had a stream of
vapor, I fed it into the top of the carb and started the engine,
regulating the flow with the valve. A friend ran the weed burner, and
made sure I had pressure, but not too much. I of course didn't have
any load on the engine, but I ran it up to about 3000 on the tach, and
held it there awhile, and moved up and down the range. The engine was
sitting on the shop floor with water plumbed from a faucet for cooling
as we often did with engines we were playing with. Needless to say, both
doors were open so I had "flow thru ventilation" to avoid stinking the
shop up. The exhaust smell didn't give any indication that rubber was
On 07/05/2013 01:20 PM, rogers92026 wrote:
> Hello Bob,
> Before you start converting your scrap to ZA12, make sure to double check the percentages using some google searches. I think that you are high on the copper and low on the aluminum.
> I've read about various companies using tires for fuel. Like for manufacturing Portland cement which takes a lot of energy. I've tried cutting tires up with a variety of saws - - saber, reciprocal, circular and have had rather poor results even using soap as a lubricant. The blade really binds against the high-friction rubber. If you can come up with a way to shred the tires into small pieces, perhaps it might work.
> There are a lot of articles on the internet about Tire Derived Fuels (TDF) and it contains more energy per pound than coal. As you mention, the users typically blend the tire material in with coal. But from what I've read, it is also a much dirtier and smellier fuel than even coal. If you have neighbors next door, you might not be very popular with them once you start burning tires.
> BTW, if you use nitrous oxide and tires, you will have a type of rocket fuel. ;-)
> --- In email@example.com, Bob Colquitt <wahsatch@...> wrote:
>> For the last 3 years I've been driving between Chattanooga & Nashville
>> tending my late father's house.
>> AND, my accumulation of diecast, zinc alloy, is at the stage of
>> converting to ZA12 or the latest alloy which is, IIRC, 5% alum & 5%
>> copper [Generous Motors special] - rest zinc.
>> Can the tire tread scattered about, be chopped up, & used to supplement
>> charcoal [more heat?] in a furnace with forced air?
>> Seems to me I read tire tread can be used in a fluidized bed with coal.
>> OR, are there more nasty chemicals in the tire tread to make zinc fuming
>> only a minor PITA?
>> Thanks for any info!
>> -=- Bob Colquitt
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