Faster, Cleaner Gasifier Startup

[Eric Johnson]

Even though they don't make any smoke or smell at all when up to speed and running, a gasifier (mine anyway) will smoke like an OWB during the 10 or 15-minute startup period. Even after you close the bypass damper and turn on the fan, it will smoke for awhile until the gasification chamber gets up to temp and the nozzles light off.

I've been thinking, more out of idle curiosity than anything else, about how you could minimize the smoke on startup. So this morning I took 8 pieces of commercial charcoal and placed them on my two nozzles. Eight pieces--four to a nozzle, covers the nozzle openings in the firebox. I started a small paper fire with a couple of pinecones bark and let it burn for awhile. Then I stuck a few small pieces wood in there, closed the bypass damper and kicked on the fan.

It smoked for a short while and then went clear. A lot faster than usual.

I haven't used the boiler enough to have a bed of unburned coals accumulate on the nozzles, but I suspect you'd see a similar result with that. As somebody pointed out, successful gasification is all about having a good bed of coals. Lacking that, charcoal seems to work pretty well. Nice to have on hand.

 

[Nofossil]

Nice! I have one of those chimney-style charcoal lighters where you put in a piece of newspaper, put the charcoal on top, and light it. I've also seen electric ones that are basically a toaster oven heater element. Either might get the charcoal going with even less smoke. If it ever gets cold, I have to play...

 

[Eric Johnson]

I knew going into this that starting fires from scratch is a fact of life with a big gasifier and storage, and I expected it to be a major pain. However, getting a fire going is really no more than lighting a piece of paper under some cardboard with a few pinecones or bark piled on top. Works every time. As I said, a little smoke is no big deal at all, but there is a small perfectionist side of me wants to make it better.

I think having the charcoal right on the nozzles with air rushing past is a good way to heat them up with a relatively smokeless fuel source. If it works consistently and if you're cheap like me, you'll figure out a way to make your own charcoal, too.

 

[webbie]

Eric, did you try upside down fires - kindling and paper on top........

 

[slowzuki]

I've seen some reference to a manual override on the pump to bring the boiler up to temp from the storage to help light off go a bit quicker. Your setup will probably get better as the winter gets on and the boiler is still hot between firings.

 

[Eric Johnson]

Yes Craig, I think that's the way to go. You want the fuel as close to the nozzles as possible on startup. So I've been going: charcoal, pinecones, cardboard and paper--starting at the nozzles.

It's not very cold out, but the boiler holds its heat really well between firings. This morning I went out to build a small fire and the water was still 65C, even though it had been out since yesterday evening. Since I don't have the tank going yet, I've been getting by with small fires and frequent restarts. It's not shy about putting out the heat, I'll say that.

Know Your Boiler: It's amazing what you can make a piece of equipment do once you've had some experience operating it and begin to understand why it does what it does.

 

[hkobus]

Erik,

You sound like you have the same idea's I have been toying with. I bought thid unit since we moved to town. (I'm a wood burner at heart and cheap dutchman to boot and believe smoke is a waste and nusance) I was sold on the smokeless burn and the fact that this is proven technology. My dad has seen this used in WWII and since in many european countries.
Since my heat storage is nit ready, I needed to find a way to reduce the Btu output. To do this I shortened the nozzle slot by inserting some fire brick pieces between the ends of the slot to just before the air inlet tubes. In your model you could probably just close off one whole slot. With that I also tempered the air by moving the slide on the blower. This setup as worked like a charm for the last few weeks.

Sure like you charcoal idea.
:coolsmile:
Thanks

 

[Eric Johnson]

Excellent idea. The more I think about it, the more I really like it. I don't see why blocking off one nozzle wouldn't work. Tonight I'm going to put a firebrick over the opening of one of my nozzles, fire it up, and see what happens. Half capacity sounds just about right for now.

Nice group of new gasifier owners we've got developing here, along with a few veterans like nofossil and slowzuki. I'm thinking all our rigs are going to run a lot better this winter than if we'd all tried to go it alone.

Hopefully we can entice some owners of Tarms, Garns, Greenwoods, etc. to join the fray. Maybe just mentioning those brand names will cause people to "Google in."

Let's see:

Tarm Solo 60
Tarm Solo 40
Greenwood Boiler
Garn Boiler
BioMax Boiler
EconoBurn Boiler
Woodgun Boiler
Atmos
KP Pyro

List 'em if you got 'em. List 'em and they will come.

 

[hkobus]

Erik,

You may also have to adjust the air, I found the flame more unstable when I did not. I run at about one third of the opening on the blower adjustemnt at this point. Good luck.

Henk.

 

[Eric Johnson]

Are you talking about the slider adjustment on the blower body or the adjustment with the screw below the blower?

Actually, I have two of everything (blowers, adjustment screws, sliders), so maybe all I have to do is shut the air down completely on the nozzle that I'm not using. No way to shut off one fan, however, without digging into the wiring.

Anyway, I'll give it a shot and let you know how it goes.

 

[Nofossil]

On my brother's homemade gasifier, too much fan was a problem. Life got much better when we throttled back a bit. It uses a 3 speed 12Vdc heater fan out of a Dodge truck.

 

[hkobus]

Yes I adjusted the fan, I feel it is to early to mess with the screws yet. Once I have some more time and equipment to measure the effect I may attempt the set screws.

 

[Eric Johnson]

I'm doing it tonight Henk, and it's working pretty well. I put a piece of firebrick over the back nozzle and closed off the air supply. The one in the front lit off and has been burning well ever since. Basically, I'm operating at half capacity, which is handy when you don't have any place to put excess heat. So thanks again--I think that was an inspired move on your part and one that I plan to exploit. And I did shut off the air supply through the screw for that nozzle, as well as the fan baffle.

 

[TCaldwell]

With the garn there are there are only 2 moving parts, the loading door and the blower motor, hence no supply air adjustment possible, the only variables are volume and moisture content of wood and ambient boiler temp. A (fast start) fire or high starting boiler water temp will minimize morning sickness to under 5 minutes. Also suspect the 400k btu/ hr fire rate and the open, low mass fiberfrax secondary burn chamber help. However too much surface area of wood in the primary chamber will cause puffing and not enough area for secondary gasses to flow properly, resembles a locomotive or a owb. Has anybody actually monitored secondary burn temp lite off differences based upon cast nozzle mass , could a lighter mass nozzle refractory cut morning sickness time?

 

[Eric Johnson]

I bet nofossil has. That sounds like it's right up his alley.

In my very limited experience, I've noticed that the starting temp of the water jacket, firebox and nozzles all play a role, as does the presence or absence of charcoal around the nozzles. I suspect that the ambient temps outside might be a factor, and the material you're trying to start the fire with definitely makes a difference. Essentially, I think that if you can fire it off and heat things up with a relatively low-smoke fuel like charcoal before you start producing smoke, it will be hot enough to eat it once you do.

I'm used to conventional wood boilers which smoke but never go out during the heating season. That's good, because they smoke even more on cold startup and take forever to get warmed up. So I'm not used to handling much kindling, cardboard and other firestarters. I like pinecones and charcoal, but bark, which burns like crazy, produces a lot of smoke and you're going to see it coming out the stack if you try to use it for cold starts.

 

[Nofossil]

I bet nofossil has. That sounds like it's right up his alley.

I have monitored combustion temperature a few times, but not enough to draw conclusions yet. We're working on an oxygen sensor. In order to figure this out definitively, we'd have to do a series of controlled experiments and keep a logbook. Really, we need a flue temperature sensor as well. This is starting to sound like work....

 

[Nofossil]

Update - first fire with my new low-mass labyrinth combustion chamber. I built a fire as usual, but with 6 or 8 pieces of dry white pine in the 3/4" - 1" size range along with a similar amount of hardwood, same size and a little larger. Switched to gasification after 5 minutes of very low-smoke warmup, and it caught.

At that point, flue temp was 250 and the water jacket was 30 degrees C.

Took another 5 minutes to get cranking, but I'd rate it as one of my better starts.

After the first ten minutes, my pristine white labyrinth had dark creosote / soot deposits all over it. After another half-hour, it's as white as snow again - actually cleaner and whiter than in the pre-fire photo below.

Feels like progress. Thanks for the ideas and inspiration.

 

[Eric Johnson]

That's pretty cool. It looks to me like you should get even better heat transfer.

I've been running on one nozzle since last night, as per hogstroker's excellent idea. It works fine; takes longer to get up to temp, but stays in the high 60s/low 70s and the wood lasts a lot longer, of course. The front nozzle lights right off and burns hot.

I liken it to putting a smaller nozzle on your oil gun. If it gets cold tomorrow as predicted, maybe I'll try loading it up good and see if it can stay in the zone. The way I look at it, my 200 Kbtu boiler can now run at 100k for the price of one firebrick. Pretty neat.

 

[Burn-1]

Nofossil is that new combustion chamber an upgrade or improved re-design replacement for the Orlan products line or is that a DIY setup?

 

[Nofossil]

Nofossil is that new combustion chamber an upgrade or improved re-design replacement for the Orlan products line or is that a DIY setup?

It's a DIY improved re-design replacement

There's another thread with more photos and some history here.

 

[EricV]

Excellent idea. The more I think about it, the more I really like it. I don't see why blocking off one nozzle wouldn't work. Tonight I'm going to put a firebrick over the opening of one of my nozzles, fire it up, and see what happens. Half capacity sounds just about right for now.

Nice group of new gasifier owners we've got developing here, along with a few veterans like nofossil and slowzuki. I'm thinking all our rigs are going to run a lot better this winter than if we'd all tried to go it alone.

Hopefully we can entice some owners of Tarms, Garns, Greenwoods, etc. to join the fray. Maybe just mentioning those brand names will cause people to "Google in."

Let's see:

Tarm Solo 60
Tarm Solo 40
Greenwood Boiler
Garn Boiler
BioMax Boiler
EconoBurn Boiler
Woodgun Boiler
Atmos
KP Pyro

List 'em if you got 'em. List 'em and they will come.

Hey, it worked, I googled in and now your stuck with me, haha.

I have a Tarm solo 40. I installed it last winter and used a bit without the tank. I now have a 1000 gallon tank I built myself, that is now online (working) as of this past weekend. so far so good.

The tank started out at 65 degrees but it was up to 160 last night.

This forum looks real interesting and full of energy minded folks.

Thanks
Eric

 

[Burn-1]

EricV, tell us more about your tank. Could you share some pictures?

 

[Eric Johnson]

Welcome to Hearth.com and our new Boiler Room, EricV.

Yes, how about some details? I'm putting the finishing touches on my tank right now.

 

[Nofossil]

I now have a 1000 gallon tank I built myself online as of this past weekend. so far so good.

That's pretty good - most of us just talk about tanks online, but you've actually built one online ;-)

Seriously, any pictures, descriptions, heat exchanger designs, performance data, lessons learned, insulation techniques, plumbing, tank construction - any information that you can share would be of interest. Welcome aboard.

 

[EricV]

Sorry, meant to say that it is now online, as in working, oops.

I'd be happy to share. but it is only my personal experience with data gleaned from anywhere I could read.

I don't have any pics yet but I will take some tonight when I get home.

I've only fired with the tank attached twice. Saturday evening and again Sunday. It took a while to get from 65 to 160. I hope now to not let it go below 120 so subsequent firings should be shorter.

I have the Tarm solo 40 that I purchased last year (x-mas time). I built a small addition on the back of the house, 12 x 16. Half for the boiler and half for added laundry room space.

I plumbed it to my tank in the basement with 1" pex through the floor so there are no exposed pipes, etc.

In the basement I have a Wiel-McLain oil boiler and the house is all baseboard fin and tube (except the new addition is in-floor which is run of my domestic tank.

I have a Tri-Tube, indirect domestic water heater at is a priority zone off my oil boiler.

The tank is just over 8' x 4' x 4', steel frame with 3/4 plywood for sides plus 2" foam all the way around the inside. Inside that is a 60 mil EPDM Firestone pond liner. I picked Firestone as it was the only one I found that rated the liner for enough heat, I forget now what they spec'd it at but it was enough.

The piping scheme I came up with (again, experimentation) is the 1" pex flows from the Tarm to the boiler. This way the house and domestic gets first crack at the hot water from the boiler. From the boiler to the tank which has 1" splitting to two coils of 3/4" copper for a total of 200'. It then returns to the boiler.

So that's the circle of life in my situation. Last winter I fired the Tarm without the tank and it seems to work just fine so far.

The only concern I have so far is the speed at which the tank heats up. but, I'm premature there as I've not fired it from say 120 or 130 as of yet, that will be tonight.