John_Mc
Elite Member
- Joined
- Aug 11, 2001
- Messages
- 4,563
- Location
- Monkton, Vermont
- Tractor
- NH TC33D Modified with belly pan, limb risers & FOPS. Honda Pioneer 520 & antique Coot UTV
A former business partner of mine was a wood combustion guru. He designed a couple wood fired boilers, and repaired and redesigned faulty control systems on commercial-scale wood chip boilers. He gave me the full technical explanation at one point (most of which I no longer remember). What it boils down to is that some moisture is needed to regulate the combustion process. What the ideal amount is varies a bit with the design of the combustion chamber/system (there are some commercial boilers designed to burn most efficiently with the wood chips just below the fiber saturation point - which is around 30% or a little less for most species). If you want to design a system from the ground up to burn most efficiently, you'd design it for around 15% MC, but sometimes there are other considerations. (In the case of the commercial systems, it's relatively quick and easy to get wood down to the fiber saturation point. Once you do, the wood chips won't freeze together, so there is no need for inside/heated storage. Even though they could eke more efficiency out of they system if they designed it to burn 15% MC chips and purchased chips of that MC, they don't because it's expensive to dry truckload after truckload of chips. It takes a fair amount of time and/or energy to dry the chips that much. Aside from the cost, it's a lot of inventory for a supplier or customer to keep on hand - which also costs money.)
