Thank you to everyone who came out for the workshop and made it such a pleasurable success.  As usual, we had a very interesting cross-section of biomass thermal conversion enthusiasts, about 60 in total over the weekend.    Where else but at a wood gas and biochar workshop can you find hippies and rednecks, liberal academics and AM talk radio jockeys, grumpy old guys and well dressed financiers all mixed together, turning wrenches together, and getting along reasonably well in the process.  In fact, most of them get along so well they and were still trickling out on Thursday– over a week after the first enthusiasts started arriving.

Kelpie Wilson of the International Biochar Initiative wrote a nice article and posted a nice gallery of the full show.  It was published in the Huffington Post and Truth-Out. See here:  http://www.huffingtonpost.com/kelpie-wilson/post_1050_b_760217.html

The goal of the longer workshop format this time was to take on some long-anticipated projects requiring more than the usual weekend to finish.  In the end, and as usual, none of the 4 main projects got exactly to the end state we wanted, but all of them pushed the ball significantly down the road.  We’re extremely happy with what was accomplished, the details of which are elaborated below.


Kubota 10kw Power Pallet Report

The big news of the weekend/week was not the impress of ALL Power Labs’ engineering, but rather the impress of the engineering on display by Kubota.  I’m amazed how smooth running these kubotas 3 cyl engines are.  It is very odd to have a proper industrial design engine at this small of size.  Kubota does very impressive work.  All the workshop attendees stood around and talked about the same.  Given things were so quiet, it was easy to have regular conversation right at the genset.

Pictures of the power pallet and other workshop events are in the forum gallery here: http://www.gekgasifier.com/gallery/browseimages.php?c=44

Our long runs tests, however, turned out to be not as long as desired.  The power pallet worked without hiccup for each of the 5 days we ran it, but fuel preparation, instrumentation and datalogging proved to be more than we bargained for.  Keeping a full instrumentation suite up and running, along with tracking the fuel mass and moisture input, energy output, and char/ash byproduct, proved much more difficult than just operating the gasifier.

This was complicated by our starting with fresh cut cedar wood chips at 100% moisture (dry basis), thus quite a bit of drying was needed to get the fuel to the under 30% range which the GEK can handle.  I’ve been surprised how much higher fuel moisture content a gasifier can handle with a full heat recycling rig like the Hot TOTTI.  We’re regularly seeing good operation in the 20-30% moisture range, which is about twice what is typical.  It is easy to get to the 20-30% range with just air drying if you presource and store your fuel for a bit (which we didn’t).  Still, you can’t run freshly cut wet wood.  We ran out of ready fuel on Thursday afternoon, right about the same time everyone fell over exhausted anyways.

Nonetheless, we put in 5 days of 6-12 hour runs.  The cyclone catch jar was still without any black goo at the end of the 5 days of running.  Just dry soot and ash.  The last two days had the fuel and power monitoring fully online and reasonably accurate.  Here’s what we learned about our “fuel in to energy out” efficiencies, while running at an average of 4kwe.

10/13 (Weds)-
Dry Mass Consumed: 31.4 kg
kWh Produced: 24.75
kg/kWh: 1.3
Average MC: ~24% (mass weighted average)

10/14 (Thurs)-
Dry Mass Consumed: 26.6 kg
kWh Produced: 21.75
kg/kWh: 1.2
Average MC: ~35%

I’m thrilled to see “fuel to power” ratio of 1.2-1.3kg per kwh for this small of gasifier-genset.  Remember that each component in the system (gasifer, engine, genhead) gets less efficient as their size decreases.  High efficiency is always more difficult at smaller scale.  The above “fuel in to energy out ratio” is at the better end of the numbers reported for much larger units.  The power pallet efficiency is mostly made possible by the Hot TOTTI thermal recycling system.

We’ll be continuing these long datalogged runs in the coming weeks.  Now that the fuel tracking and instrumentation solutions are fully set up, ongoing proving runs are much easier to do.

Lister spark conversion

After some technical drama with a cut trace on the ignition control board, the spark converted Lister finally came to life Tuesday eve.  Ron Ohler, Mike LaRosa and Jay did the honors, but Ken Boak, Marcus Hardwick, Michael Shiloh and Peef did much of the preparation that made it possible.  Pictures from the first run are in the workshop gallery here:  http://www.gekgasifier.com/gallery/browseimages.php?do=browseimages&c=44&page=3

This time the spark plug it in the COV valve on the side of the head.  The diesel injection was left intact so we can switch back and forth easily between the two.

For the first run, we fired it on diesel then switched over to woodgas while running.  It was surprisingly easy to switch over, much easier than with a carburetor on gasoline, as you could get a sharp switch off of the diesel via the shut down lever.  No usual fuel wandering back and forth as the carb runs out of fuel.

The timing was fussed with quite a bit.  We ended up with it about 45deg advanced, and it still didn’t seem fully enough.  One problem we found with the coil over plug arrangement is you can’t get a timing light on the spark plug wire, as there isn’t one.  The inductive clamp won’t work over the plug boot.

We had the kill-a-watts hooked up on each of two legs and topped out at 2.9kw.  That was pushing the absolute max. 2.5kw was easy to maintain.  This was at about 600rpm.  A little below the standard 650rpm.  Shaky shake started above 600rpm.

The compression is the 13.3:1 of last time.  The injector is leaking a bit too.  We’ll likely get a bit more power once we return to 17:1 and get the injector better sealed.

All in all, i’m happy how much power it made, and how smooth it ran. It seemed to run about the same as it did with the spark plug in the injector hole.  The biggest difference was in the timing adjust. so given the lack of good control on that last time, it is difficult to compare properly between the two modes.  But it was clear that it works just fine in the COV valve, and this is good news, as this is a better place to put it.

The ability to start on diesel then switch over with a hard “fuel off” switch was very nice.

Thank you Ken, Marcus, Ron, Mike and the others that made it go.  Another very impressive effort by all of you.

The rest of the Workshop: — Biochar making and Planting– Fischer Tropsch experiments

Many interesting things happened.  We’ll report on them in the next Geknews.  This is getting too long already.

In the interim, there pictures of the 350.org 10-10-10 biochar planting in a Berkeley community garden here: http://www.gekgasifier.com/gallery/browseimages.php?c=44

The biochar talks were fabulous too.  All the talks are available on the APL YouTube channel here: http://www.youtube.com/user/allpowerlabs .

Germany Workshop, October 22-24

The Germany workshop starts in about 5 days.   We’re hoping this workshop will be easier for the GEK interested in Europe to get to than flying all the way to Berkeley.

The Power Pallet arrived in Frankfurt on Friday.  It should be at the workshop site by mid week.   We’ll be on the plane over on Tuesday.

Holger Roswandowicz, the sponsor of the workshop in Germany, has posted an update on the event here:

http://nrg-consultants.com/biomass/15kwbiomassbackuppowergenerator/workshop-zellingen/index.html

excepted text:

Jim Mason from Allpowerlabs, Holger Roswandowicz from NRG-Consultants.com and Herbert Hornung from Hornung Energy have planned to do the first EU GEK-workshop in Zellingen near Würzburg.

It is planned, that Jim is speaking about the Basics of Gasfications on Friday 22.th October in the eveneing.
If possible a GEK run with the new Kubota Motor is planned for the evening

On Saturday, the major workshop day Jim plans to make 4 RUNs in a day
He will make explanations before, during and after a run.

Meanwhile Holger Roswandowicz will explain the major differences between the markets and properties of the wood gasifier power gens and chps.

Holger is CHP-project consultant / engineer and has many experiences with standard chps,
Biomass CHPs from Talbotts and the Biomass CHP from Stirling Denmark and has experience with many applications out in the industries.
He is specialized in flow and heatmetering solutions in different applications (metering).

Herbert Hornung is the owner of the large Store Möbel Hornung and naturally the founder of Hornung Energy.

He is the owner of the GEK now with the Kubota Motor and allows us all to make this workshop at his loctaion in Zellingen.

On Sunday the 24th we will repeat the runs and go more in depth with the technology of gasification and speak about the capabilties of your planned applications, if you like.

Jim, Herbert and Holger are williing to serve the GEK-owners and its later modifications in the EU.

The workshop starts on late Friday after 6.00 pm (18.00 Uhr).

You can call Holger under ++49 171 1988 926
His mail is info
Follow on Twitter twitter.com/nrgconsultant
Follow on Facebook www.facebook.com/nrgconsultant

Gasification and Biochar Workshop this coming weekend- October 8-11

1. GEK Power Pallet 7 day endurance test with new Kubota engine and Mecc alte genhead
2. Syngas-to-Liquid experiments via Fischer Tropsch
3. Lister spark conversion
4. Biochar database samples generation with the BEK

Workshop Details:

Opening Intro/ Lecture: Friday, October 8, 7:30-9:30PM
Weekend Build, Run and Test: Saturday, Sunday, and Monday, October 9-11, 11am – 7pm

Location: ALL Power Labs, 1010 Murray Street. Berkeley, CA
Contact: jim ^at^ allpowerlabs dot org
Cost: Free if you are a GEK or BEK owner, either through self build or purchase. Otherwise, $100 for weekend. Pay via paypal here.

For more information and RSVP instructions for the workshop, see: http://www.gekgasifier.com/forums/showthread.php?t=413

—————————————————————————————————————————————–

1. GEK Power Pallet 7 day endurance test
2. Syngas-to-Liquid experiments
3. Lister spark conversion
4. Biochar database samples generation with the BEK

Jay has started a journal in the forum to track progress on the Gas-to-Liquids test rig.  See here:  http://www.gekgasifier.com/forums/showthread.php?p=1539#post1539

The Lister diesel spark conversion discussion is mostly in the yahoo woodgas forum, but with the highlights copied over to the gek forum here: http://www.gekgasifier.com/forums/showthread.php?t=312

The Power Pallet and Biochar disccussions are less localized.  However, one recent page of interest is the recent grate shaking tests Bear has started to compare and characterize the performance of various grate shaking modes and perf hole sizes.  See here: http://gekgasifier.pbworks.com/Grate-Shake-Testing-20100922

Workshop Details:

Opening Intro/ Lecture: Friday, October 8, 7:30-9:30PM
Weekend Build, Run and Test: Saturday, Sunday, and Monday, October 9-11, 11am – 7pm

Location: ALL Power Labs, 1010 Murray Street. Berkeley, CA
Contact: jim ^at^ allpowerlabs dot org
Cost: Free if you are a GEK or BEK owner, either through self build or purchase. Otherwise, $100 for weekend. Pay via paypal here.

For more information and RSVP instructions for the workshop, see: http://www.gekgasifier.com/forums/showthread.php?t=413

While Jim and Nick are in operating gasifiers in the Philippines, the rest of the APL team is here in Berkeley, CA holding down the fort and setting up the logistics for our upcoming series of workshop around the world.  Our date for the workshop in Germany is now set and Power Pallets now have a new, lower price.

Power Pallet Price Reduction

More details can be found here: http://www.gekgasifier.com/gasification-store/gasifier-genset-skids/

Jim’s report from Tuwa the Laughing Fish, an ecovillage a bit north of Manila in the Philippines

here’s some pictures from the power pallet set up and first day of the workshop. http://www.gekgasifier.com/gallery/browseimages.php?c=40

we have a very interesting collection of people from local govt, ag development agencies throughout the philipines, and business folk. about half of the audience is involved with other gasification projects in the philipines, most all rice husk gasification projects.

the big topic of concern is the waste water from wet scrubbing based solutions, and the large size of typical gasification plants. seems we’ve heard this theme before. most all the rice husk gasification systems are using open top downdrafts of one sort or another, feeding it with a low void space fuel, and thus getting a very dirty gas out of the reactor. the dirty gas problem is “solved” in the filtering, but at significant cost, size and disposal complexity.

the potential for a small compact system that can be made mobile and put along side threshing, drying or milling machinery, and moved from site to site, is of great local interest. new things are possible when you move a gasifier towards a washing machine size object, away from a typical industrial plant size.

of course the current gek reactor will not handle small granular fuels like rice husk. we have other ones in process that will, and do so with good tar conversion in the reactor, so the same minimized clean up system will still be possible.

currentely we are running wood chips made locally, at about 30% moisture content. the totti heat recycling systems are giving us much more tolerance to run higher moisture content fuels. everything here is extrememly wet. air drying seems to only get things into the mid 20s moisture. our moisture meter on the fuels we’re chipping is reading 30% on average. that is the driest we can find without purpose drying the fuel.

even with this 30% moisture fuel, the restriction in the hearth is staying at 850-930c on a 3kwe load. this corresponds to 1200c or so at the nozzles most likely (but unmeasured). these are the temps we want to see for full tar conversion. we had a white filter and unmolested sawdust after our first runs yesterday.

the chipped fuel we’re running looks like this. we’re also using it in the bottom of the filter, as you can see here. the rest of the filter is filled with rice husk and sawdust.

Power Pallets in Farm Show

In the most recent issue of Farm Show Magazine there was a great article about the Power Pallets.  We spend a lot of time reading Farm Show around the shop.  Also included in this issue were some very informative articles on other topics of general interest including “How to Make Money With Skunks” and “Deer Urine Business Pays Off.”  If you are not familiar with Farm Show Magazine – we highly recommend it.

Upcoming Workshops Around the World

The dates for our workshop in Germany are set.  Kenya is soon to follow.

• Germany, October 22nd-24th, 2010 with Holger Roswandowicz of http://nrg-consultants.com/ Details and registration here: http://www.gekgasifier.com/about/workshop/germany-workshop-sign-up/

• Kenya in late September with Jon Bohmer of the Kyoto Institute at Narok University College: http://horufadhi.com/news_detail.php?nid=105

• Nigeria in winter with Yoav Platnik of www.ecopowerafrica.com

• Berkeley, California, USA, October 8-11, 2010, at APL headquarters http://www.gekgasifier.com/about/workshop/

Rachael and the APL Team

Gasification PowerExchange Workshop #9

Opening Intro/ Lecture: Friday, October  8, 7:30-9:30PM
Weekend Build, Run and Test: Saturday, Sunday, and Monday, October 9-11, 11am – 7pm

Location: ALL Power Labs, 1010 Murray Street. Berkeley, CA
Contact: jim ^at^ allpowerlabs dot org
Cost: Free if you are a GEK or BEK owner, either through self build or purchase.  Otherwise, $100 for weekend.
RSVP in the forum thread here, so others know you are coming. http://www.gekgasifier.com/forums/showthread.php?t=413
Pay via paypal here

The quarterly workshop series at ALL Power Labs offers education, research reports and hands-on experience to bring more people to successful operation of small scale gasification and pyrolysis units.  The event is open everyone, not just GEK or BEK users/owners.  So come and join us while we progressively make small-scale biomass thermal conversion a reasonable proposition, adequately advanced for everyday use

This fall we’re running the workshop in an extended format so we can take on some long-anticipated projects requiring more than the usual weekend to finish.  The main event will be four days this time (Friday through Monday) but with one of the projects continuing until the following weekend. (yes, we’ll have a live webcam so you can watch the whole process, even if you’re not here).

This round we’re elaborating the guest lecturer contributions, given how enjoyable the talks by Dr. Devinder Mahajan (SUNY, BNL) and Dr. Kyoung Ro (USDA, ARS) were during the June workshop.   We’re also adding a poster session for GEK/BEK owners and other researchers to present their work and machines.   In previous workshops, the combination of intro information, hands-on project building/running, and reports on current research has proved to be a great mix– thus we’re further elaborating things in this direction.  If you would like to give a talk or poster presentation during the weekend, please contact us at [EMAIL="gek"]gek[/EMAIL] and we’ll get you on the agenda.

Here’s the list of projects for this round of the workshop.  All four will run simultaneously over the weekend.  Everyone can participate in all of them.

1. Power Pallet 7 Day Endurance Run:
A 168 hour around the clock run of the GEK 10kw Power Pallet.  This will include full data logging of the fuel input, gas output and power produced, as well as all internal reactor conditions.  The goal is to fully characterize the performance the GEK 10kw Power Pallet a long, continuous run operation.

2. Biochar Database Sample Generation:
Characterized biochar and bio-oil making with the [URL="http://bekbiochar.pbworks.com/"]Biochar Experimenter’s Kit (BEK)[/URL], using attendee provided biomass.  Bring your own biomass and we’ll convert it to biochar through a variety of process conditions, temps and residence times.  Samples will be analyzed post workshop to seed a public biochar samples database.

3. Syngas-to-liquids workshop:
Experiments in reactor design, catalyst making, and system control with various guest lecturers from the field.  We’ll explore and assess the potential for small-scale DIY gas-to-liquids solutions, and look at some new ways around the long-standing hurdles for making it reasonable.

4. Changfa diesel and Lister spark conversion for Woodgas:
More run tests and electronics hardware hacks towards an easy DIY spark conversion solution for Listers and China Diesels. We all have a soft spot for these engines, but dual fueling them is annoying.  A ready-to-go spark conversion solution is needed.

Click on each of the above for more info on the project.

The workshop begins with a Friday evening talk on the science of gasification and pyrolysis, and the new engineering solutions embodied in the GEK and BEK.  Both beginning and expert reactor assemblies will be presented, with pointers to further reading and opportunities in the field. Everyone will get a packet with lots of explanatory graphics and core data charts relating to gasification and pyrolysis.  These info graphics are also posted online here: http://gekgasifier.pbworks.com/Gasification-Graphics

Saturday, Sunday and Monday are full days of building, running and testing the physical particulars.  Wear clothes that can get dirty. Come prepared to turn wrenches, shovel char, weld and generally get your hands into the details of biomass thermal conversion.

Sign-up here: http://www.gekgasifier.com/about/workshop/sign-up/

Travel information can be found here: http://www.gekgasifier.com/about/workshop/travel-and-accomodation/

CNC Laser Cut Parts and Stainless Steel GEKs

We’ve recently moved to a CNC laser cutter solution for sourcing the raw gek metal parts.  For the last two years we’ve been making these in house with a CNC plasma cutter, but our throughput has outgrown the reasonableness of the plasma cutter solution.

Fortunately we can use the same files to outsource to a CNC laser cutting house, and have everything show up done, clean and nicely taped together in bunches on a pallet.  The locals find this MUCH superior and do not miss the de-slagging, re-drilling and general fussing with each piece off the plasma cutter by hand.  Abram, Nick, Ben and Johnny would’ve been here for the above pictures, but they were out celebrating at the local bar, telling war stories of our CNC plasma table (tales of both love and hate).

So hurray for desktop manufacturing and outsourcing (all the way to southern California).  It continues to amaze me how accessible CAD/CAM/CNC tools have made complex manufacturing processes that used to only be available at the mass scale with large capitalization.  The GEK manufacturing process would not have been possible just 10 years ago.

The full gallery of CNC laser cut parts is here: http://www.gekgasifier.com/forums/showthread.php?p=1409#post1409

As you can see, we’ve sourced the parts in both mild steel and 304 stainless steel.  We can now provide GEKs in all stainless for those who want it as such.  The default and value optimized GEK is a mix of mild and stainless steel.  We only use the exotics where they are really needed, and minimize stainless for price optimization and reduction in shop health issues around working it regularly.  But for those who really, really can’t live without their stainless indulgence, and find it pleasing to pay extra for the indulgence, we now agree to indulge.  We can now provide any GEK reactor or add-on you want in stainless, finished with a fancy brushed surface.  Prices are on average about 50% more for the stainless versions.  Inquire to gek for the details.

BEK at Biochar Conference at Ames, Iowa State University
Full gallery here: http://www.gekgasifier.com/gallery/browseimages.php?c=37

Bear Kaufmann Reports:

All Power Labs attended the Biochar 2010: U.S. Biochar Initiative Conference in Ames, Iowa this past week.  We brought with us a full GEK TOTTI and Biochar Experimenters Kit (BEK) for consideration and Q&A.  We now have the BEK in 5 university and research sites, and hope it will soon become a meaningful platform for comparative biochar research.  Recently we launched a BEK wiki, which will soon grow into a parallel biochar information resource like the GEK wiki and forum.  See here for the beginnings: http://bekbiochar.pbworks.com/

The conference was host to many major researchers on biochar including Johannes Lehmann, Christoph Steiner, Stephen Joseph, and others exploring the potential for biochar to be a potential component of sustainable agriculture and energy production, including Gloria Floria and Hunter Lovins.

There were a number of recurring themes in the presentations at the conference.

• Use of biochar to improve nutrient recovery and cycling in agriculture: filtering and capturing nutrients from manure lagoon effluents with biochar, reducing weight of manures through charring to make return of nutrients from over concentrated animal farming operations to fields more viable, and the necessity to manage phosphorous in agriculture wisely as it becomes a limiting nutrient.
• Integrating biochar creation into systems to capture the various product streams: biochar, heat, bio-oils.
• How to source biomass in a sustainable manor: cropping systems that yield biomass with low inputs and yield other ecosystem services, biomass sources.

One of the final plenary talks was given by Laurens Rademakers of Biochar Fund which is working to reduce deforestation in Africa (Cameroon, Congo) by improving agriculture yields and minimizing the pressure by farmers to clear additional forest for farming.

Iowa State hosted the conference, feeding attendees with ample supplies of local and corn-based foods and showing their facilities and research on bio-energy and biochar.  More information on the conference is here:  http://www.biorenew.iastate.edu/events/biochar2010.html.  Hopefully the papers and posters will be up here soon.

The gallery of all our photos from the conference is here: http://www.gekgasifier.com/gallery/browseimages.php?c=37 If you were there, feel free to add more.

Get your own BEK and join the learning and testing over the biochar proposition.  Details of acquisition are available via email post to gek.

Driving a gasifier is hard.   Proper hearth dimensioning and good fuel is important, but not enough to guarantee success.  Most of us learn an informed operator is also needed.  In fact, an informed operator is often the most important variable on the road to success.  Unfortunately, it is also the variable that varies the most.

Things would be much easier if we had the equivalent of a “speedometer” and “tachometer” to guide the operator.  Something like a car where we have a gauge that tells us how fast we are going, and another gauge that tells us how hard we’re pushing the engine.   Or maybe even idiot lights or automated control systems, further reducing the need for “intuitive expertise” from the operator.  How have gasifiers existed for over a century without these sorts of simple gauges and numbers to tell us what to do?

ALL Power Labs has been working for the last year to formalize downdraft gasifier performance, and through this, to find simple measurement points and number guidelines which tell the operator what is going on in the reactor.   The goal has been to find the easy to measure “indicator values” for the min and max pull rate of the reactor, as well as real time signals which correspond to tar conversion success or failure.  Tar is difficult to measure in real time.  But maybe there are combinations of temp and pressure measurements with high enough correspondence to tar production to give us the same information more easily.

The result of this work is “The Masonic Method”– a formal operation and tuning method for an Imbert type downdraft gasifier.

The Masonic Method uses two temperature and two pressure measurement points to guide all critical operational issues with a  downdraft gasifier.  The same 4 points are also used to diagnosis common problems with a gasifier as well as guide configuration refinements of nozzle sizing, hearth geometry and fuel specific optimizations.  How specifics on using these same measurement points for tuning will come in a separate post.

The two temperature and pressure measurement points needed are as follows.  See also the above graphic.

Temperature 1: Hearth restriction
Temperature 2: Bottom of reduction zone
Pressure 1: Pressure drop across nozzles
Pressure 2: Pressure drop across full reactor (nozzles + bed)

For more info on the tests and analysis that generated the correspondences between temperature, pressure/flow rate and tar conversion, see here:  http://gekgasifier.pbworks.com/Multi-fuel+Run+Comparison

________________________________________________________________________________________

Your Gasifier Speedometer
(aka: the manometer)

The most helpful gauge for informed gasifier driving is a manometer measuring the pressure drop across the reactor.  The pressure drop across the reactor tells you to an approximation how fast you are pulling the reactor– or in other words, how much gas you are making.

For good results, you need to pull gas between the min and max gas rate acceptable for the gasifier hearth dimensions.   Pulling too fast or too slow will create problems.

-Pull too slow and you’ll make a mess of tar.
-Pull too fast and you’ll make soot, weak gas, and ultimately clinkers.

This min and max gas rate band is fairly narrow, thus the need for an experienced operator to find it.  Fortunately we can quantify this “good band” and have the “newbie” read a gauge to approximate “expertise”.

Our tests have shown the min-max pull rate band as 2″ to 10″ of h2o vac across the reactor (before filtering).  Stay within these limits and you’ll have good results.  For even better results, try to stay in the sweet spot,, which we consistently find to be 4-6″h2o vac range.  You can push things up to about 12″ and idle down to about 1″, but you are tempting trouble at these extremes.

Here’s these “speedometer” manometer numbers as a chart.  You might want to print these out and keep them with your gasifier.

12+: Overpull
10: Maximum
8: OK
6: Good
5: Ideal
4: Good
2: OK
1: Minimum
0-1: Underpull

These values can be read manually via a simple manometer, or we can use the same values to inform idiot lights and electronic automation.  In all these cases, the critical new learning here is that we can formalize the min-max rate, and make informed operating decisions in relation.  We do not need to guess, nor do we need to rely on years spent face down in the black goo.

These numbers assume a well configured gasifier with reasonable hearth geometry and nozzle sizing.  We can get close to reasonable dimensions using the standard Imbert charts.  For further refinement of these dimensions and configurations, see the tuning section below.

Yes, different gasifier types, sizes and fuels will introduce some variations in this scale, but they are less than one would fear.  Also, these variations can be quantified with the same formal system, and thus compared between machines.  Refinements and addenda are expected to the above guidelines as others use it.

—

Your Gasifier Tachometer
(aka: the thermocouple)

Minimum RPM

Tar cracking in an Imbert type gasifier is achieved through creating a high temp combustion lobe across the full hearth area, and forcing tars to pass through it and crack from the high heat.  The goal is to spread cracking adequate temps across the full hearth volume –all the down to the restriction– and not let any tar pass around the edges, center, or other cool spots.

Full and complete temp PROPAGATION is what is important here, not just high spot temps in front of the nozzles.  Actually, the temp in front of the nozzles is somewhat irrelevant. What matters is how well the high temp has filled the entire hearth and propagated all the way to the restriction.

Our hypothesis is that the best way to measure this “fullness of propagation” is the temp achieved at the restriction, NOT the temp right in front of the nozzle.  If the nozzles are sized reasonably, and we find some X adequate tar cracking temp still present at the restriction, we can reasonably conclude that the hearth is filled with a temp somewhat above this.  Tar most likely will be passing through these higher hearth temps, and at the very least will pass through the directly measured temp at the restriction (given the narrow gas passage).

In our recent tests we’ve been very pleased to find there is, in fact, a very strong correlation with temp at the restriction and tar in the output gas.  There is a very clear and rather linear relationship between temperature at the restriction and tar cracking success.   There is similarly a rather poor relationship between temps right in front of the nozzles and success in tar conversion.

You can see test results on the correspondence between restriction temp and tar conversion here:
http://gekgasifier.pbworks.com/f/1259099233/summary2_tar_s2_v_tredc.png

The takeaway from the tests is that if we have 900c or above at the restriction, tar will disappear “completely” form the output gas.  Tar destruction continues to be reasonable down to about 800C at the restriction.  Below here tar passing will rise to unacceptable levels.

This gives us a very simple probe point we can monitor in real time to see if we are making tarry gas or not.  It is also a somewhat cooler measurement point than the right at the nozzles, thus our thermocouple is less likely to melt.  We can use this measurement point and numeric value as a new rule for helping newbies drive a gasifier successfully:

“Always keep the restriction temp above 800C!  If you let it go below this, you will have lots of tar in your gas”

—

Maximum RPM

If a thermocouple at the restriction is your best monitoring point to know when things are too cold, a thermocouple at the end of the reduction zone is your best monitoring point to know when things are too hot.

A thermocouple at the end of your reduction zone tells you how fully your reduction is finishing.  Pull too fast and the reduction reactions will not have adequate time to complete.  Gas exit temp will rise as a result.

Gas energy density increases the further we run reduction to it lowest temp potential.  Also, CO reversion to soot and CO2 increases the higher temp the CO leaves the bed.  Run the temps up even higher and the ash will begin to fuse into clinkers.  This is the ultimate “redline” point of the gasifier—when you start to make clinkers.

This “redline” RPM of the gasifier appears to be about 900-950C out the reduction bell.  Above here I anecdotally notice significantly increased soot production and soot filling the cyclone jar.  Go significantly above it and you’ll fill the hearth with clinkers.

Thus we can give the newbie a simple rule to define the max pull rate and temp before things will start melting down.

“Always keep the restriction temp at or below 900C!  If you let it go above this, you will create excess soot, weak gas, and ultimately clinkers that will plug the hearth.”

—

When to Shake the Grate

As the reduction bell gets packed with ash, the resistance to gas flow increases.  This will increase the pressure drop across the reactor.  At a constant gas flow rate, we can see this as a rising reading on the manometer.

Unfortunately, gas flow rate will also change this reactor vac reading.  We need to find a signal that is independent of, or co-varies with changes in gas flow rate.  The way we’ve discovered to do this is to monitor the RATIO between the pressure drop across the nozzles and the pressure drop across the bed.

The pressure drop across the nozzles is NOT impacted by variations in bed packing.  The pressure drop across the nozzles follows from the nozzle hole size, not anything happening later in the bed. We can measure this with a pressure port somewhere in the reactor around nozzle level, as shown in the graphic above.  The pressure drop across the bed is the total reactor pressure drop reading minus the nozzle reading.  The total reactor reading is measuring the combination of BOTH the nozzle and bed pressure drops.

Once we know the nozzle and bed pressure drop readings separately, we can find the ratio between them, and this ratio will stay about the same independent of flow rate.  Or rather, both of the pressure readings co-vary near proportionally with flow rate changes, thus the ratio between them stays constant.  This ratio will only change when the bed packs and the resistance to gas flow through the bed rises.

When the bed is properly purged and gas is flowing well, we like to see at 1:1 ratio between the nozzle drop vs bed drop.  Said another way, the nozzle pressure reading should be about 50% of the total reactor pressure reading.  (This of course assumes your nozzles are sized correctly in the first place, which is covered below in the tuning section.)

If this ratio changes, we know the bed is packing.  Proportionally more pressure drop is coming from the bed than the nozzles.  When we see this, we know to shake the grate and restablish the correct ratio.   We can use this ratio threshold for manual grate shaking, or as input to an automated grate shaking system.   We can most simply read this ratio off a manual visual manometer.  Or the computer can read this ratio and respond accordingly via a micro-controller.

Note: This “new” pressure reading at nozzle level is easy to take on the GEK by using the lighting tube as your sample tap. Put a barb on the end of the lighting tube (once done lighting) and attach it to the standard manometer.  Put the other channel of the manometer on the usual end of the reactor tap.  Now you have the total reactor pressure drop and just the nozzle pressure drop.  The difference between the two readings is the bed drop.

Jim

We’re running two 10 hour endurance tests on the GEK 10kw Power Pallet for the workshop weekend, this Saturday and Sunday, June 5 and 6. One of the locals has set up a webcam on the proceedings so you can watch the process online.

See here for the show: http://www.gekgasifier.com/web-cam/

The Power Pallet is running with full automation of fuel feed, woodgas/air mixture and grate shaking. All temp, pressure, and flow rate particulars are being datalogged for presentation after the run, as are the specifics of fuel in to electricity out.

The fuel is regular wood chips. No exotically produced chunks. We’re running a variety of loads usually in the 3kw-6kw range.

We started the rig at about 1pm pacific time and we’ll shut down tonight sometime around 11pm. Then we’ll do the same thing tomorrow.

We’ll be posting more info here in the forum over the weekend, so check back to see how things are going.

jim

Maker’s Faire 2010, San Mateo, CA.

Last weekend we ran the GEK Power Pallet for two days at the Maker’s Faire to power our “Power Parlour” of food and drink making.  Wood chips in to popcorn, margaritas, cookies and bacon out.  Like this was simple all along (which it unfortunately has been not).  This was a dry run for this coming weekend workshop where we’re planning a long endurance test of the GEK Power Pallet.

So far things continue to be good.  We were able to run two 8 hours days at Maker’s in a fully automated hands-off manner, using common softwood chips.  Things ran satisfyingly well the entire time with no active tending of any system.  We filled the fuel in the morning and once in the afternoon.  That’s about it.

You can see the Power Pallet in this gallery Popular Mechanics did of the Maker’s Faire:  http://www.popularmechanics.com/home/how-to-plans/maker-faire-2010-gallery
We also have a gallery of Maker’s Faire in the GEKforum here:  http://www.gekgasifier.com/gallery/browseimages.php?c=32

Other Art

The Popular Mechanics gallery also has some good pictures of various “moonlighting” projects by APL folk.  When we’re not building gasifiers, most of us also build large scale mechanical, kinetic and pyrotechnic art.  A few of these get airtime in the PopMech gallery, including:  The Rocketship by Nathaniel, who is also the main APL prototyper.  Fishbug is by Jess Hobbs, the co-founder of APL, and Rebecca Anders, previous APL prototyper.  And the Apocalypse Stagecoach, Nick’s current creative indulgence when he’s not running GEK manufacturing with Abram.

Most of these creative curiosities orbit around the institution of Burning Man.  But more generally, they tend to seep up from the art and innovation groundwater under the Bay Area.  The continuum between art and tech has been deeply muddled locally, which is likely why such interesting things get cast up from the region with regularity.  Google, Burning Man and the Maker’s Faire all drink from the same creative aquifer.

We’ve been deeply fortunate to have this rich pool to draw from towards solving the problems of small scale biomass thermal conversion.  Building large machines on fire with slumming Phd’s has been an oddly effective preparation for new engineering strategies on gasification and pyrolysis systems.  Who could have known?  Either way, there’s a little context on how were got here to our two year anniversary.


Weekend Workshop next weekend, June 4-6

We’re putting things in order for our two year anniversary workshop this coming weekend.  If you want to join us but have yet to RSVP, see here: http://www.gekgasifier.com/forums/showthread.php?t=348

The focus of the weekend will be on running the GEK, BEK and Power Pallet.  This will be hands-on learning and running more than project building for this round.  Hands will get dirty.  Biochar, clean gas and electricity will be made.  Arrive at the end of the weekend knowing how to make it all work back at your homestead.

The Friday eve talk is expanding with some interesting guest lecturers.  My (Jim Mason’s) gasification intro talk will be shortened so others can also present.  We’re honored to have joining us Dr. Kyoung Ro of the USDA ARS in South Carolina who will present his work on: “Pyrogasification of animal manures to produce combustible gas and value-added biochar”.   Dr. Devinder Mahajan of Brookhaven National Laboratory is also joining us to give an overview of his syngas to liquid fuel work at Stony Brook and BNL.  If you are unaware of Dr. Ro or Dr. Mahajan’s work, I encourage you to consult the internet.  Both are pillars in the field and we’re very lucky to have them joining us in the GEK/BEK collaboration.

Prof. Sundar Narayan will also join us from Lambton College in Ontario, Canada.  Sundar is the owner of the first GEK we shipped, which he’s returning to the mothership for the anniversary workshop.  In return he’ll take home a new v4.0 GEK.  Hopefully we can run the first GEK side by side with the current GEK over the weekend.

Two Year Anniversary Sale Final Week

This is the last week of our anniversary sale. To qualify for the discounts below your order needs to be placed and paid for by the end of Sunday, June 6th.  Here’s the nice prices for the next week.

- $1,000 off: Fully automated Power Pallet
- $750 off: Manual Power Pallet
- $500 off: Level IV GEK with all Hot TOTTI heat recycling add-ons (pyrocoil and auger feed drying bucket)
- $100 off: Basic Level IV GEK kit.

More info on these items is in the GEK store here: http://www.gekgasifier.com/gasification-store/.  You can find us to go through more of the details of your application at gek.

New Power Pallet Gallery

Here’s a gallery of the most recent power pallet we shipped.  This one went to Latvia.

http://www.gekgasifier.com/wpgallery/10-15kw-gek-gasifier-kohler-genset-skid-2/latvian-skid/

You can see we’ve gone back to a traditional C channel frame skid under the engine genset.  The CNC cut version turned out to be more work than the benefits realized.  The C channel method is stronger with about the same weight.  On top you can see the new 55gal stainless steel drum hopper.  And on the bottom we’ve added rubber mounting feet under the skid and under the GCU box to further isolate vibration.

Here’s another version of the same with just the engine-genset and wood gas mixing control.  Everything except the gasifier, as this went to a researcher in the UK already with the gasifier part.  See here: http://www.gekgasifier.com/gallery/browseimages.php?c=31&userid=

That’s enough for now.  I hope to see many of you this weekend in Berkeley.

jim