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Sunday, March 17, 2013

Explaining How Wood Gasification Works Part3

The best made unit still is the one that you make from junk yes I said junk. They just seem to work better than if you buy all brand new metal don’t ask why but they seem to me to fire up faster and burn better.
Now let’s get back to how to filter I now like to say make it for burning pine if you make it so it can do that than if you burn good hard wood it will be over kill but if you want to use it for a car or truck. Than you have it made right the first time and if you do drive around and need wood and if you can get free wood than you won’t be scared to use it. For filtering this is what I have learned that if you keep some heat in threw the first few filters and slowly drop the temp each one it will filter out the tar a lot better. Another thing is cyclones with heavy tar just don’t mix too well they build up a heavy layer of gunk inside them and it’s a real pain to get out. So I worked on a new way to filter using washable stuff this so far has been really nice for several reasons first is I don’t need to keep making or buying filter goods. Now I know you want to know what am I using in my filters and how do I make them, easy for the main filters I just use tubing that is upright so one has the gas enter the bottom and flows up the next enters the top and flows down. Now for what I use as filter medium here are some of the items stainless steel wool, ball bearings, small rocks, pure light, glass marbles, BB’s like the ones used for a BB gun. The way I now look at it is this for the first filters I like stuff that holds heat and for the last few I like stuff that will take out heat. What I think I have figured out is if the gas moving through the filters is still warm the water vapor stays in the gas and the tars don’t dry up letting the tar stay moist. This I see as a big plus for one reason the tars don’t dry up and crystalize making what most know is cresol. With holding some heat I keep from making it and if I have a wash setup not a bubbler it should wash off the tars keeping my filters cleaner. After I go through say 6 tube filters or more then I go into a sawdust filter out of that I go into a cyclone filter to catch any dust or water left. Now as you can see its not rocket science to make one it just takes some welding drilling and metal cutting and some thinking.
This next one I am going to make I think I will try even to wash out the first few filters as it is running using a spay setup at the top my hope is that by have a water flow it will collect more tar and dust and keep my filler clean. I already am planning on having to change stuff up some I may need to add a few cyclones in to help dry out the water vapor from the gas but as long as I keep it so I know the gas will be wetter gas than I just need to plan for it. The only thing I can’t plan for is just how wet the gas is and the one variable as it is run for several hours how much will that effect the wetness of the gas making more or a lot more moisture in it. See the one variable here is will the water get hot enough to make a big difference on how much is added in moisture to the gas.
Now how to know if a filter is a good one or not easy the cleaner the gas is the less you can see it what I mean is wood smoke is easy to see white in color how I test a new filter is I take off all my filters from my unit then I fire it up. Once it’s going good and I have a burnable gas 5 to 15min burn time. What I do is I take off my blower and put on the new filter and put the blower on the end of the new filter. The first thing I look at is how easy it is to see I use my camera to take a picture of it right off the burner unit. That gives me a good way to compare the 2. A good filter will cut out some tar and some water. There are 2 ways to test how good it is when it’s running right off the burner take a measurement of how much blue is in your flame and I like to do a time test. My time test most won’t do due to they still have tar in there mix I use a bright white chunk of cloth and put it over the outlet of the fan holding it over the pipe tight for 1 minute. Then when I put the new filter on I do the same test I then can compare the two by the color and richness and it give a real good idea and if it’s really damp I will weigh it b4 and after so I can get an idea of how much water is in the gas.
Now I wasn’t sure I was going to talk about this but I will put it out there. I still have more testing to do but I may have found a water additive that is used in some commercial exhaust systems to help clean up the gasses. If this helps at all I will talk more about it when I get a lot more testing done with it. If it’s not working like it could I may still throw it out just to see what other people think of it and maybe someone will find something else better. There is another filter medium I have yet to try out its used for a lot of stuff and for filtering out a lot of different stuff and I think it’s worth a try too. If that works out I will let you all know about it that is if it helps at all not sure.