[Gasification] another aproach to producing a clean gas
gasman
gasman at welho.com
Sat Jun 3 16:24:13 CDT 2006
To Jim Mason
There are two fundamental factors, that make the
idea of "storing" woodgas on a vehicle unrealistic:
1. CO will "fall apart" (more complicated?) when compressed:
CO ==> CO2 + C.
2. As the heating value of woodgas is low, the amounts
for a reasonable using time are huge; the motor supposed
to go idle, will have a heavy job in driving a compressor
"for almost nothing"... back! But of course the draft in the
gasgenerator will be kept up.
Energy-vice it would be easier to use an electric ventilator
to supply a torch, or some useful heating.
Still, these are only handling the symptoms, and covering up
the real reasons!
During the WWII a turn down ratio of 18:1 was achieved
just by taking care of good insulation, so there is a lesson
to take after!
Now, a natural addition is to take care of good heat-exchange
from the ready made raw-gas to the primary air.
Another prominent factor is to dry out both physical and
the greater part of the "chemical water" from the fuel, before
it reaches the hearth.
That makes a better starting point for making good gas, even
with increased turn down ratios.
On my way today 4.6.2006 to the yearly woodgas jamboree...
Max
----- Original Message -----
From: "jim mason" <jimmason at whatiamupto.com>
To: <gasification at listserv.repp.org>
Sent: Saturday, June 03, 2006 9:55 PM
Subject: Re: [Gasification] another aproach to producing a clean gas
> thanks for the hilsch vortex tube link. i had never head of that.
> very
> interesting.
>
> on the turn down rate / tar problem, i'm curious what the prior art
> is for
> either bladder or high pressure tank storage of woodgas. it seems
> that
> several problems could be addressed here by the addition of a small
> onboard
> storage system, with a pump mechanically driven off the engine (or a
> secondary electrical pump).
>
> imagine a pump/storage system that automatically started when the
> engine was
> a idle, so as to maintain gas production, but to the end destination
> of
> storage and not the engine. such storage production would both
> maintain
> gasifier rates, as well as provide a small storage pool that would
> be tapped
> when high power is needed, and on start up when there is not yet any
> gas.
> (and yes, obviously the pumping and storage will rob some energy)
>
> it seems such a system, combined with the oxygen sensor auto mixture
> adjust
> would go a long ways towards making gasifiers in mobile applications
> more
> convenient for contemporay use expectations. now admitedly, i am
> not a
> promotor of convenience on most any front, but we must admit that
> gasifiers
> are quite a long way from even veg oil systems in the ease of
> running them.
>
>
> so i've been trying to think how gasifier systems might be more
> helpfullly
> automated, with modest add on systems that don't increase complexity
> greatly.
>
> auto mixture control, and automated storage for surge and start up
> support
> seems like a good starting point.
>
> j
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On 6/3/06, drew <drew at artforging.com> wrote:
>>
>> Hi Andy,
>>
>> Sounds like a great setup, I have a suggestion for cleaning up
>> the
>> gas stream. It may be difficult for you to impliment , but if
>> your
>> wood hopper is truely air tight, maybe not. Some people may also
>> see
>> it as inefficent, but for my purposes (stationary engine) it isn't
>> as I
>> will explain.
>>
>> Imberts can provide a clean gas stream only if the gas flow
>> rate is
>> matched to the fuel, and equiptment setup. If as you say, idleing
>> produces fouled plugs then perhaps you are trying to run at gas
>> production rates below what your setup can produce cleanly (you
>> might
>> want to start by seeing if your reactor tube temperature is
>> dropping).
>> What I have some sucess with (not with an imbert) is keeping the
>> gas
>> flow constant by shunting gas to a flare (will be my water heater)
>> when
>> my load is not present. I use a pressurized hopper (2psi) and
>> produce
>> gas at a steady rate almost regardless of load in my system, that
>> makes
>> it realitively easy for me. This keeps the flow rate through the
>> gassifier consistant. I have thought that in a vacum "driven"
>> imbert
>> perhaps if you were to install a one way valve on the air flow to
>> the
>> tures so that air could only be drawn there then you could feed low
>> pressure air to your hopper, or the tures directly, then have a
>> vacum
>> switch on your intake manifold of you engine that would open your
>> flare
>> valve (you would need a pilot of course, but water heaters need a
>> pilot
>> anyway). There are probly other ways to impliment this, but the
>> idea
>> is just to keep the gas flow more consistant, especialy at low rpms
>> on
>> your engine. One thing to keep in mind here is that vacum drawn
>> systems are inherently safer, in that any leaks in the system will
>> only
>> draw in air, but in a pressure driven system if you have leaks you
>> will
>> likely leak flamable gasses, including the deadly CO, take extra
>> care.
>> In the setup I am describing, your system would only be a
>> pressure
>> system at low rpm, it would revert to a vacum system when you
>> increase
>> rpm enough to suck the one way valve open. You might also
>> want to
>> try a smaller diameter and possilbly longer reactor tube or a tube
>> made
>> of refractory? but I would ask Doug W. at fluidyne about that? I
>> have
>> also wondered about the idea of using refractory "balls" in the
>> bottom
>> of the reactor tube to increase the gas dwell time in the high
>> temperature zone, they would have to be large to allow lots of
>> space for
>> ash to drop around them but if you have a grate shaker, or are in a
>> moving vehical it might be a way of keeping the gas exposed to heat
>> for
>> a little longer (to give the tar more time to crack).
>>
>> Recently I have been wondering about including a hilsch vortex tube
>> as a
>> molecular "sorter" if it can sort hot air molcules from cold,
>> perhaps
>> heavy from light eg, tars from hydrogen CO? I know that there
>> is
>> another venturi like device that can do this, but it seemed to be
>> quite
>> tight tolerance, this seems a little looser. If anyone out there
>> knows
>> more about the other venturi system perhaps send me a link?
>> http://www.visi.com/~darus/hilsch/
>> <http://www.visi.com/%7Edarus/hilsch/>
>>
>> keep on truckin
>> Drew
>>
>> --
>> This message is intended only for the addressee(s)and may contain
>> information that is confidential and/or copyright. If you are not
>> the
>> intended recipient please notify me by reply email and immediately
>> delete
>> this email. Use, disclosure or reproduction of this email by anyone
>> other
>> than the intended recipient(s) is strictly prohibited.
>>
>>
>>
>> _______________________________________________
>> Gasification mailing list
>> Gasification at listserv.repp.org
>> http://listserv.repp.org/mailman/listinfo/gasification
>> http://www.repp.org/discussiongroups/resources/gasification
>>
> _______________________________________________
> Gasification mailing list
> Gasification at listserv.repp.org
> http://listserv.repp.org/mailman/listinfo/gasification
> http://www.repp.org/discussiongroups/resources/gasification
--
----------------------------------------
Jag använder gratisversionen av SPAMfighter för privata användare.
1483 spam har blivit blockerade hittills.
Betalande användare har inte meddelande i sin e-post.
Hämta gratis SPAMfighter här: http://www.spamfighter.com/lse
More information about the Gasification
mailing list