[Gasification] Getting both heat and char .....
Energies Naturals C.B.
energiesnaturals at gmx.de
Thu Jan 5 17:53:26 CST 2017
Many thanks to Doug, Paul and others.
Sorry, I had a busy day away from home and could not check my mails.
The Shasta 2 carbonizer is a very interesting design.
How could it be optimized to make high temperature "flare" gas?
Recover heat from the char cooling to preheat the combustion air?
Rolf
On Thu, 5 Jan 2017 16:26:09 -0600
Paul Anderson <psanders at ilstu.edu> wrote:
> Doug, (and a thank-you to Art for his comments also)
>
> Your archive update
> http://www.fluidynenz.250x.com/Feb2015/Shasta2update.html was very
> informative. Although larger and with operational differences, there
> are strong similarities with the Chip Energy Biomass Furnace that Paul
> Wever and I designed and made some years ago. Info is at
> chipenergy.com That is not a TLUD, but is a true up-draft gasifier with
> a few innovations that I have written about in 2007 as AVUD (Another
> Variation Up-Draft) gasifier.
> > http://www.drtlud.com/wp-content/uploads/2012/08/BP53-Anderson-14.pdf
>
> I agree that what Rolf is seeking is not a TLUD.
>
> You wrote:
> > May be the ash from the carbon dust will settle in the tunnel
> > depending on combustion gas velocity. Usually, a correctly sized flue
> > stack is required to assist with removing the exhaust gas, and this is
> > where ash dust can become an emission.
> I have not experienced carbon dust or ash from carbon dust or ash dust
> with the AVUD design.
>
> Again, thank you for your strong support for gasification of biomass.
>
> Paul
>
> Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
> Email: psanders at ilstu.edu
> Skype: paultlud Phone: +1-309-452-7072
> Website: www.drtlud.com
>
> On 1/5/2017 12:27 AM, Doug wrote:
> >
> > Hi Paul,Rolf and Colleagues,
> >
> > This is to clarify Paul's questions. I hope the separations do not
> > confuse too much.
> >
> >
> > >Pyrolytic gas can be quite wet so precise temperatures are risky to
> > quote.
> >> Yes. There is no scrubbing or drying or other preparation of the
> >> pyrolytic gas. In the TLUD world, the gases are usually created in
> >> the 500 C to 650 C range. And the raw biomass fuel might enter with
> >> as much as 15% to 20 % Moisture Content (MC).
> >>
> >> If the MC of the raw fuel was lower (such as 5% MC), would that help
> >> raise the temperature?
> >
> > The short answer is yes, we don't need steam to displace gas volume.
> >
> >>
> >> Hypothetical question: Part A. if the pyrolytic gases were cooled
> >> to below 100 C, water could be removed by condensation, and we would
> >> have lots of wood vinegar. However, there would also be massive
> >> amounts of tars and "gunk" being deposited also. However, the
> >> final, non-condensed gases just might have the desired temperature
> >> when combusted. Those gases would be H2, CO,
> >> methane-and-related-gases, and what else?
> > Cooling the gas is a waste of the heat that it contains. Any condensed
> > tars, hydrocarbons, or vinegars may have applications, but also add to
> > the technical difficulties for their collection. Their removal, other
> > than moisture best removed by drying the wood, reduces the calorific
> > energy of the pyrolysis gas. Difficult to calculate, but also adding
> > to the gas heating value will be carbon particles. Normally we would
> > seek to minimize these by using a cyclone, but ceramics need reducing
> > atmospheres, or read that as carbon rich heated atmospheres, so carbon
> > dust is great.
> >>
> >> Part B. Alternatively, after the removal of the wood vinegar,
> >> perhaps the remaining gases plus the reheated tars, etc. could be
> >> reheated to become a dry, quality gas for higher burning
> >> temperatures. All of this would be with losses of thermal energy
> >> during condensation and then the need to add thermal energy. Could
> >> this have benefits that could justify the expense?
> > I think the previous answer covered this, but I see no benefit at all
> > to this suggestion. At a later date after there is a system working,
> > you will then have opportunity to extract condensates. Our experience
> > tells us that as toxic black liquor, the less you have the healthier
> > the working site. No exaggerating, it's a health and safety hazard.
> >>>
> >>> What I can tell you from experience, is that it always burns hotter
> >>> than clean producer gas, upwards of 1,050C,
> >>>
> >> If that is the maximum, will this be sufficient for Rolf and his
> >> friend to use? There is no way to turn 1000 C into 1300 C, correct?
> > Not well explained, sorry. Clean tar free gas will not burn over
> > 1,050C, but if the system design produces pyrolysis gas which has all
> > it's hydrocarbons, then the temperatures will be upwards and over
> > 1,050C, a basic tar test for cleaner specification gas,
> >
> >>
> >> But your next words I do not understand.
> >>>
> >>> 13-1500C is a rough rule of thumb for gas exiting the combustion
> >>> chamber.
> >>>
> > If you combust pyolysis gas full of hydrocarbons, then the flame
> > temperature will be 1,300-1,500C. One of the most difficult areas of
> > combustion is that thermo-couples start going crazy over 1,300C.
> > Expensive ceramic ones damage too easily, so once the TC melts, you
> > know the higher temperatures are present, possible over 1,500C.
> >
> >
> > >I am not understanding what that means. The combustion chamber is
> > the "burner" of the pyrolytic gases?
> >
> > The short answer is yes if we were just creating heat. Ceramics like
> > Rolf is seeking to fire, are done in a tunnel kiln, and the tunnel
> > becomes the combustion chamber. The geometry is important to create
> > the combustion phenomena, but to design this we first need a tunnel
> > kiln to use.
> >
> > >>It has a very high radiation factor useful for refractory
> > application, but the price for this is that you will get a high ash
> > content in the kiln and flue dust emissions.
> >
> > >Something in the above sentence is not clear to me. The "kiln" is
> > part of the gasifier or is it where the materials are being heated?
> > And the pyrolytic gases of TLUDs do not >have ash in them. And I am
> > not understanding the source of any flue dust emissions.
> >
> > The gasifier is close coupled to the kiln, and the burner is mounted
> > in this case, on the end of the tunnel kiln which forms it's own
> > combustion chamber containing the ceramics. The spent gas has to exit
> > the tunnel at some point, above the condensation temperature. May be
> > the ash from the carbon dust will settle in the tunnel depending on
> > combustion gas velocity. Usually, a correctly sized flue stack is
> > required to assist with removing the exhaust gas, and this is where
> > ash dust can become an emission. It would be good to put aside TLUD
> > understanding, as they work on a totally different principle not
> > relevant to this project need.
> >>
> >> Are your comments somehow referring to the FULL gasification
> >> processes in downdraft gasifiers (pyrolysis AND char-gasification are
> >> both occuring)?
> > No, Downdraft gasifiers more often than not make pyrolysis gas and
> > need char extraction to work. Full gasification as you say, need
> > minimum bed disturbance and between 1-4% of the fuel drops out as
> > char. Rolf only has a downdraft engine gasifier for his first trials,
> > and we should get plenty of pyrolysis gas out of that, at least for
> > the first tests to fire the ceramics. Maybe we will have to extract
> > char as well, but all that is still a long way off at this point.
> >>>
> >>> The actual combustion is complex, but achievable in a non regulated
> >>> situation, emissions being the issue, both dust and toxic gas
> >>> CO,CH4, and Dioxins. Combustion of these gases have been our focus
> >>> for some 6-7 years, and current work at CalForest in California, is
> >>> to use this gas to dry the incoming fuel to the charmaker.
> >>>
> >> The above sentences seem to indicate that your explanation is about
> >> FULL gasification and not about only the pyrolysis process with
> >> resultant charcoal creation.
> > We take raw producer gas from the Shasta gasifier, meaning hot
> > cycloned hydrocarbon free downdraft gas for the boiler green house
> > application. This has high carbon dust content which burns to ash.
> > This is a problem for the boiler, but just needs more cleaning cycles
> > than anticipated.
> >
> > The Charmaker is an updraft system and burns to waste the very dirty
> > pyrolysis gas. The gas flare vertically from high stacks making them
> > safer, as we have no space to work with them on the ground. The
> > radiant heat cooks you from about 3-4ft, so the chances are, unless
> > you have stood by an oil rig flare, many researchers just haven't
> > acquired this type of experience from pyrolysis gas flares.
> >
> > You might like to look again at the Fluidyne Archive last update
> > showing the charmaker and gas flares in action. The bigger flares at
> > higher output are not shown mainly due to us too busy keeping up with
> > the input fuel flow. Earlier updates show the Cyclomix burners and
> > combustion chamber hooked to a heat exchanger, so there is plenty of
> > info to brush up on as we developed these larger gas making system
> > components. When operational, we collect data from those points
> > important to both the gasifier and process, including continuous gas
> > analysis, which cannot be used for pyrolysis gas. (to dirty)
> > http://www.fluidynenz.250x.com/
> >
> > Doug Williams.
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
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--
Energies Naturals C.B. <energiesnaturals at gmx.de>
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