Got this question from Eric, and reposting it here so he can get some intelligent responses.
I have a couple of questions and would like for you to help me out. First off I would like to explain a little of my gasifier setup. I have a 420cc ~12hp generator running on the wood gas. The Gasifier has 5x 3/8" nozzles with a 4" throat. The system consist of the gasifier, a cylone, a tubular heat exchanger, a 9"x9" 30" tall filter box, silicone hose to ball valves for throttle/gas regulation, a condensation catch can, and a smaller 6"x6" filter box. The primary filter box has wood chips in it and the secondary has shredded paper. The wood I’m burning are small wood chips that typically come from a chipper shredder of which is laid out to dry before burned. The air intake enters at the top, on the side of the gasifier and travels down to a chamber which feeds the nozzles. I’m only measuring metal temperatures of the gasifer from the outside and this is what I have.
At throat area on outside shell: 350-400 deg
Gas outlet to cyclone: 140-160 deg
Cyclone out to heat exchanger: 100-120 deg
Heat exchanger out to primary filter box: 85-105 deg
Filter box out: 60-80 deg
Catch can:40-60 deg
Secondary filter box: 45-65 deg
Ambient Air Temp: 35-55 deg
Right now the biggest problem I have is tar build up on the intake valve and making it stick pretty bad. As well, I have a lot of moisture throughout the system with different amounts at each drain point, about a quart of water total after a couple of hours of run time. I also have to change out the wood in the primary filter box every couple of days because of moisture and tar build up. I’m ultimately wondering if you can help me figure out what could be improved. Here’s just some of my simple questions:
Is my throat too big?
Is my cyclone/heat exchanger not taking out enough moisture?
Should my heat exchanger be taking out more heat?
Removal/Reduction of moisture help reduce tar turning it into soot?
Is soot easier to clean/filter than tar?
One theory I have is if the throat is too big, then there’s not enough time to allow the water to convert to good wood gas. Also, I’m taking out a lot of moisture now, but I feel like I have more than I should in the first place and I can’t remove it fast enough which is why I have tar throughout the system. So, should my heat exchanger be cooling the wood gas down more than what it’s doing. These are just some of my problems I have and I much appreciate your input. I’m sorry for making this long but I want to make sure I provided enough information for you to help me.