I have a friend that asked a question the other day. "Is it possible to create a small switchgrass pelletizer. so that someone with a small rural homestead could efficiently grow and harvest their own fuel?"
This sparked an interest in me, and questions started to arise. In order for the fines of grass to stick together, how little or much moisture is needed? What is the actual process that pelletizing takes? And, most of all, why would someone want to do it?
Why? Having renewable resources is a hot topic these days. Man has been using fire to heat homes since the beginning. Wood as a fuel is what people default to when you think of this. Burning corn has been an alternative that is attractive because it is renewable on an annual basis unlike a tree that takes decades to grow. Switchgrass, which can be harvested multiple times a year produces as much if not more heat per pound as corn and depending on the desisity of the pellet can rival wood.
Next, I was looking at the process it takes to produce pellets. First, bales are chopped into small chips and or fines. These fines are then dried to a moisture content of 10-12%. then the fines are mixed, extruded out a die and cut to length. In the mixing process moisture or steam in added to facilitate the fines to bind together during the extrusion process.
Once the process was set the question is how to get this process to a size that can be mobile, affordable and easy to use and monitor. Having worked with a farmer in the past the designed a built his own harvester, I started to think of ways to pelletize cornstalks, hay, and straw to a density and form that can be used by cellusoic ethenol plants. But this led me away from the original quest of a rural homestead being able to grow its own heating fuel.
How would you like to mow your grass and get fuel for you home at the same time. The clippings from your lawn mower would be chopped into small fines, compressed to reduce the moisture, and extruded into pellets that will burn in a pellet furnace. Now any piece of property becomes a source of fuel. Road sides are mowed and the pellets are used to fuel the boilers in our municiple building and our schools get theirs from mowing the football and soccer fields. Or the fuel in burned to produce steam for a turbine that powers our building.
