[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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