This project was originally initiated at Northern Arizona University (NAU) to improve the economics through the recovery of Pine-Oil. An ongoing project to recover the pine-oil had been successfully in recovering some of the oil, but the process was not suitable for commercial use.  The project was redirected to investigate fluidized-beds to recover the oil.  We learned a lot about handling the wood chips, and some interesting things about recovering the oil,

The fluidized-bed work at NAU used a special form of pulse-fluidization.  Some additional work was done at a forest products company to further develop the technique. It was found to be difficult, and awkward to integrate with the blowers and cyclones associated with the process, and that effort was shut down.

Over a year later we wondered if we could improve the drying technology and built a bench scale unit to investigate the possibilities.  Although we started with the specialized pulse-fluidization that we had used at NAU, we discovered that by changing some of the design we found we did not need the pulse-fluidization.

The “trick” to this is to use high-velocity jets to inject the dryer gas. This prevents the “rat-holes” from ever getting a chance to form.