Just this morning I finished up a short department for the September issue of Biomass Magazine inspired by a conversation that I had with Hess Hess at the Idaho National Laboratory. The interview I did with Hess was the kind of interview that I find the most rewarding. Hess’s technical fluency is top shelf, but it was his ability to make his incredible stores of knowledge accessible to me.
Hess’s assertion is that if biomass is going to continue to gain market share in our energy portfolio, our means of collecting it and preparing it for further conversion into energy products is going to have to evolve. Hess and I often found ourselves talking about the challenges of making corn stover ready for conversion into cellulosic ethanol. If you don’t follow that corner of the broader biomass industry very closely its helpful to know that the earliest pioneers in the frontier of cellulosic ethanol production from corn stover have found it challenging to receive, pre-process and move corn stover bales into their fermentation tanks.
In Hess’s mind, the problem is a fundamental one. He asserts that cellulosic ethanol plants need to get out of the business of preparing corn stover for conversion altogether. He points to this coupling of pre-processing and conversion as a rare and risky endeavor in industries that handle and convert solid materials.
By decoupling these two process steps, Hess believes that the work of doing some real valuable pre-processing, well beyond must running materials through a hammer mill can take begin. To be fair, I’m sure the folks who have invested in cellulosic ethanol plants would love to be able to buy conversion ready stover, but these biomass depots that Hess and others think are in our future simply don’t exist yet. Or don’t they?
Pellet producers are in the business of making a biomass stream conversion ready, right? Certainly when looking at heat, and even power markets, wood pellets are a conversion ready energy product. Still, as Hess continued to talk I found myself thinking about other biomass streams and other final energy products and the role pelletization could play. It didn’t take long before Hess mentioned some work being done to pretreat corn stover with a mile ammonia bath and then pelletizing it. The ammonia begins to break down the stover making it more susceptible the enzymes in the biorefinery and the pelletizing makes it a material that is vastly easier to handle than raw corn stover.
Hess also mentioned forms of torrefaction that while not full torrefaction is more similar to coffee roasting. This process greatly reduces the downstream energy required to pulverize difficult biomass feedstocks.
Hess closed by telling me that we had to get away from simply beating on biomass with hammers. The wood pellet industry has done quite well with just that approach, thank you. Still, Hess’s words certainly ring true as our industry looks to expand beyond our current markets or even as we look to bolster the value proposition within the markets we serve.