Hi Marcus, pallet wood works great in gasifer nails too. The wood is free. The only draw back is putting the biochar in the garden, old rusty nails that have not rusted away and your Wood cutting blades. I use a sawall with a metal cutting blade. I try to only
Use nail free and the pallet pieces with nail goes into the retort barrel a magnet pick up the nails out of the charcoal.
Bob
Jan, I can have 5, 7, 8 , 10, or 12 nozzles. Tar can not get by the proper size restriction open for your gasifer design and engine size that you are using. With the proper depth from the nozzles to the restrection opening and then reserve charcoal depth to the grate.
High velocities nozzles to low velocities nozzles it is all going through one opening the restiction opening. If it is to larger it will make tar. If it is to small it will limit how much gases you can make.
Think about it. I have 12 nozzles and my velocities are lower at the nozzles at a 1000 rpms of the engine then with your 5 high velocities nozzles. the air is colliding with the air shooting across from the other nozzles through the hot charcoal. Your hot lobe area might be a little higher than mine because of the velocity at the same 1000 rpms. of the engine. The one thing that is the same in my gasifer and yours is the restiction, just one opening for all the air and moisture and gases to pass through.
Different Gasifiers but one and the same restriction opening. Sizing it to the engine size you are using and gasifer design and you are good to go. Lots of other variables in operation of the gasifer to be considered like fuel types and sizes. But for tuning the gasifer seems to come down to the depth and restriction opening and to the grate or bottom of the gasifer in a grateless gasifer making a good charcoal reserve.
Bob