I just came to think of a quite different system to put the silo-gases running!
Take exhaust from the motor just opposite one outlet channel in the exhaustmanifold, where the pressure pulses are strongest.
Pipe these “pistol-shots” into a few liter bucket with a backflap valve.
From this bucket, run a 1/2" or less tube to the down leading leg from the silo to the cooler.
Try to form an ejector downward to the cooler; blow hole 0,5 --1mm for a wild blow beam…
Hmm l like the idea Max! A venturi/propane burner ejector!
This leads me to think further. Since now there is artifiial and undepended to the thermosiphone flow of gas, l culd draw the hopper gases to the front of the vehicle and trugh a cooler mounted before the engines radiator. From there, condensed (dry and free of tar-smoke) hopper gases culd either be drawn back in the hopper, or, being rather dry and containing mainly nitrogen and CO2, expelled altogether out from the tailpipe together with engines exhaust gases! This way useless exhaust poluted hopper gases are prevented to enter the gasifier completely.
Hi, Kristijan!
2.11.2017
Let’s see! Ejecting out N2 out from the silo loop system brings immediately in new COLD N2! — to the middle of the hearth!
Internal “circulation help”, yes, but not new heat diluting…
Hi Kristijan, your design needs to be more like WK. First the bottom of your condensation tank is going to fill up with tar, and that is good, so there is no reason to have fins on the bottom. Just 2 drains, 1" for water and it will be a stand pipe drain about 5" from the bottom. 2" for tar that drains the bottom of the tank. Make this tank as big as you can. I can fill my tank of water in one day of driving, wish it was bigger.
The pipe coming up out of the condensation tank and going back to the hopper is not needed. Just connect your bottom hopper pipe two the other pipe and make sure it is going up like you have it drawn. All of your pipes can be hooked up the same way. Also weld fins on the pipes that are vertical. Now for getting air to the pipes , build a in closer box around your pipes in that part of the trunk and use your fan to bring air in and have exit out the top. You can also have a air scoop under the car to bring air in when traveling down the road. A handy thing I put on my truck was valve on the 1" pipe and I can open and close it from the driver seat.
The return gases are cold, wet and mixed with a bit of exhaust gases. They first need to heat untill they can rise back up the wood bed, and suffocateing the hearth while goeing down.
If they are disposed, the volume of them gets replaced with strongly preheated air that keeps the hearth hot eaven at wery low engines gas demand, while produceing exess heat riseing up the bed, drying the wood. In a way, turbocharged hearth.
But, at the expense of higher fuel consumption.
Bob, yes, you show and describe the original plan. But two problems have occured that lead me to the slimer, monorator way.
Lack of space and the use of a fan. Althugh the fan seems wery quiet by its self, once its runing in the trunk, the story is different. Its anoying and above all, a potential cop magnet at regulat police patrools.
I have to come up with something that is both simple, foulproof, safe and quiet.
Out goes warm steam-saturated gas and back comes cooled saturated gas, but at a lower temperature level.
Most of the heat loss is in the condensed water brought to the cooler.
This results in drier wood at a lower temperature.
This results in lower heart load further down.
To overcome this heatloss, the return gas can be re-heated by a heatexchanger from the exhaust gases.
The unfortunate “topography” of the hot and cold points in the circulation system asks for external “moving power”.
There seems to be three alternatives:
A modified centrifugal fan or a “high-pressure” exhaust injector.
If the heatexchanger (from exhaust) is at the lowest point (excluding condense tank)
it can control the thermosiphonic circulation without any other “extras”!
“This results in drier wood at a lower temperature”
This is true. Allso a big priority as the hopper is nevertheless in the trunk and has to remain as cool as possible! Allso one reason why l wanted to go monorator way, as the hopper wuld need much less insulation. But since this doesent work…
There is allso one other way to circulate the gases. Useing the air nozzles as ejectors. We talked about that sometime back…
Hi Max, and Kristijan, everyone that have added fins on their tubes have noticed a big improvement in cooling and condensation of the gases than with out fins. I am not sure how many tubes Kristijan is planning on using off the hopper. If you can get air movement from the out side to the car into the container surrounding the tubes and at a good flow rate it will work. The key is a good flow rate of outside air passing by the fins on the tubes and exiting the container out the top and out of the trunk of the car. This container needs to be isolated from the rest of the trunk space area to work. Air scoops work best in front of the car down at the bottom for stealth look. You can mount them on top but they are noticeable. Caution, Winter snow conditions can plug up the scoop and this will causes air drag on the car. With the car moving most of the time the air scoop under the car will provide incoming air. Good insulation from the hopper and a air gap between the container box would help keep heat transfer from the hopper wall to the container box housing to the cooling tubes.
Here some more quick drawings and not to scale. Not sure but I think you could put 7 tubes in for cooling.
With all this said it might be just to complex to to do. The one thing that is nice about it, there no moving parts, just air flow.
Bob
One more problem is the car needs to pass anual inspection so there must be no big changes to it as such! Holes in the body have to be kept to a minimum. The one l made for the gasifier is easyaly covered, any more holes and vents wuld be hard to hide. Allso, the scoop wuld be dangerously low- danger of hitting it on road speed opsticles. And water/snow from the road! Those are problematic too.
Hey Bob, say you idle for a long time or drive real slow on your truck. How hot do the wk tubes get with that minimal air speed?
Yes low clearance would be a problem. Ok do any of the cars in your country run with sport car spoilers on them. If they do you could make one for your car that is really a air scoop or you could make a luggage or buy one for the top of the car that is really a air scoop might be hard to hide the pipe going under the car to the trunk, but it would be easy to remove for inspections. People in our country leave the ski or snowboard carrier boxes on their cars year around, shows some kind of status ( I am a skier or snowboarder). It could carry extra wood for you too. They are really streamlined.
When idling my tubes are hotter on top than the bottom, so I know they are working. Do need some temperature reading?
My hopper runs at about 160 * f to 170 * f at the top, and at about 220*f it is time to think about refilling the hopper with wood. The cooler tubes are running at a much cooler temperature.
Bob
Easy removal of all woodgas items from the trunk for inspections.
Minimum heat radiation and convection from the gasifier silo.
The rest of the gasifier and Thien cyclone are probably airtight
below a tight lid in the former exhaust muffler box?
Making a 5 – 10 mm thick watermantel around the silo and a tar-condens
gutter inside in the lower end, abowe the funnel toward the hearth inlet.
An inside condens mantel down into the gutter is necessary!
Light insulated silo.
Gutter outlet down to a cictern under the car bottom.
No “silo ventilations”! They make it hard to control in/out flows, and using
space!
The watermantel needs a strong (mobile-home) circulation pump (electric).
The water cooler under the bottom or in the front. If a skibox can’t be
used (and connected).
This is the coolest and smallest system coming up so far…
Yes the extra room for wood on top of the car wuld sure be handy for longer trips. Allso l like the spoiler idea, but its connecting all this without pipes sticking trugh cars body thats the problem. Otherwise this is the most elegant solution.
Max, you nailed it. Althugh, l am thinking to change the lower part too. The preheat box that surrounds the gasifier/baffle fits tightly in the muffer box, and the intake air doesent doesent cool it enough from inside so there is still heat radiateing trugh the trunk bottom, specialy at cooldowns. At hard pulls the water insulation of the trunk floor starts to melt. The fuel tank is near and l do not like heat being radiated in the trunk.
This calls for a design change. I might eaven have to extract the so great working baffle, it radiates a lot of heat becouse of its size.
The gasifier its self is small enough to fit inside with enough clearance to the muffer box walls to insulate it. After that, a smaller baffle or cyclone will be installed for the same reason.
I have to rip the system off becouse l have inspection this month, so there will be plenty of time/room for changes.
I like your thinking on water cooling. A bit tricky to make watertight but doable.
Time will tell!
I allso have to make aditional filtration when l put it all back.
A question for all you “condensing hopper guys”. How much condensate do you collect in the cooling rails/hayfilter? I ask becouse l am prepareing a gas filtration sistem and need to know what to expect once l am done with hopper condensation.
Thanks, l apreciate your help!
I think my wood is 20-30 % moisture content. On a 50 pound hopper load of wood I would expect to collect about a half gallon of condensate in the monorator tank . I would expect about 1/5 of that amount in the condensate tank .
I dump my monorator tank on the go so I haven’t paid a lot of attention to the amount .
This tricky to answer, but agree with what Michael has said about the wood and his system. The way my truck is built I have very little moisture going to my condensation tank after the rails, I even added more rail length. I have lots and lots of soot in that tank tho. Most of the water it going into my hopper condensation tar/water tank off the hopper rails and I think this is good. And yes my hay filter collects water also where the gases really slow down.
So the big question will be moisture content of the wood that you will be burning. My wood is less than 16% most of the time. Michael’s is a little higher.
What will your moisture content be on a average?
I do know adding fins on the hopper rails changed how my water was being condensed out that part of the system.
Michael added cooling tubes to his momohopper and he started collecting more water out of his hopper condensation tank. Take a look at Michael’s hopper cooling tubes, he has a short hopper but longer cooling tubes by put them at a angle.
I think it has a cool look to it also.
My point is this, collect as much water out of the hopper area as you can, and with that water, will come the tar. Less tar to deal with is a good thing to me in anyone’s gasifier system.
Bob
Right on Wayne, And I love my dump on the go hopper condensation valve I put in. Open it and close it from the driver’s seat driving down the road if needed. I usually wait until I am back at home, like you do. The best weed killer I have, and it is all organic.
Bob
