Students enrolled in the Integrated Design Experience (IDX) course at Washington State University are working with NARA to explore potential solid and liquid depot sites in the Olympic Peninsula region. These potential depots would fit into a supply chain that converts post-harvest forest residuals (material generally burned in slash piles) into chemical products like bio-jet fuel. In late November and early December, 2015, the IDX students conducted four webinars to distribute their results. Two of the webinars provide a rational for the sites.
Whereas an additional set of webinars provide schematic designs for each site.
These webinars are the product of work generated after visiting select forest products companies last October.
Pilot Plant at Port Townsend
The IDX students selected the Port Townsend Paper mill as a potential site to include a liquids depot. A liquids depot would process post harvest forest residuals into a sugar syrup and also produce a lignin-rich co-product. The sugar syrup could then be transported to bio-refineries for further conversion into biochemicals, biofuels and/or livestock feed. To do this, a liquids depot would be capable of performing a pretreatment and enzymatic hydrolysis process. The pretreatment step uses heat and chemicals to break apart the wood structure to expose sugar polymers. Exposure of the sugar polymers is necessary for the enzymatic hydrolysis step: a process where applied enzymes reduce the sugar polymers (like cellulose and hemicellulose) into simple sugars. Paper mills are ideal sites to include a liquid depot facility as they already have infrastructure to handle wood biomass storage and transport. In addition, they already process and market lignin as a byproduct.
In the webinar, the students estimated that a viable liquids facility would need 100,000 bone-dry tons (BDT) of post-harvest forest residual material annually to be economically viable. This amount would produce 4000 tons of glucose and 40,000 tons of lignosulfonate annually. The Port Townsend Paper mill already uses 120,000 BDT of post-harvest forest residuals annually for energy production, so the total amount of woody biomass needed annually to supply both energy and sugar syrup would be 220,000 BDT.
While this number represents a significant amount of wood biomass, it is estimated that only 14% of forest residuals generated annually after timber harvest in the Olympic Peninsula are currently used; the rest is either left on site or burned.
Using a biomass supply model generated by NARA researchers, the IDX students illustrated on maps the amount of sustainable post-harvest biomass available based on a set delivery price. Delivery price included all acquisition, processing and transport fees from the harvest site to the liquids depot. At $73 average per BDT delivered, 246,000 BDT would be available annually under averaged timber harvest scenarios. The students also estimated that 60 new jobs would be created.
The webinar presenters described three sites and provide detailed schematics within the Port Townsend Paper mill property that could potentially host the added liquids depot facility.
Micronized Wood Product Plant at Hermann Brothers
For a potential solids depot in the Olympic Peninsula, the IDX students used the Hermann Brothers Logging and Construction site in Port Angeles for their case study. A solids depot would process and store post-harvest forest residuals for energy use or for distribution to a liquids depot or bio-refinery. Hermann Brothers already supplies post-harvest forest residuals for a variety of uses and thus already functions as a solids depot. The added feature explored by the IDX students is to incorporate a micronized milling capacity to the business.
Micronized milling is a process that grinds wood material into a wood flour with average particle size of 50 microns. The advantage gained using this technology is that the pretreatment step (and costs) used to expose the sugar polymers for enzyme hydrolysis is avoided. The wood particles are so small that the enzymes, when added, have access to the polymers and can generate simple sugars. Efficient wood milling relies on electric energy, which is relatively inexpensive in some Pacific Northwest locations.
In the webinar, the IDX students estimated that a sustainable micronized milling plant would require 50,000 BDT of post harvest forest residuals annually. Using NARA biomass models, the students predicted that 122,000 BDT of post-harvest forest residuals could be sustainably delivered at a $63 cost per BDT. Three sites within the Hermann Brothers wood yard property were evaluated for accommodating the micronized wood infrastructure.
Student professional development and stakeholder benefit
The IDX students perform critical data gathering and analyses for the NARA project and for regional stakeholders. Their research results to date can be found on the NARA website.
Nearly 100 undergraduate and graduate students with varied majors including law, engineering, and design have participated in the IDX research for NARA. These students leave with an amazing understanding of biomass and biofuel supply chain issues. Already, the students are getting jobs in the region as planners, architects, and engineers and are becoming the bioenergy experts in their communities and in business.
The impact from these students entering the bioenergy workforce is a desired outcome of NARA’s bioenergy literacy goal. An additional benefit is that data and outreach accomplished through their efforts educates Pacific Northwest stakeholders and provides a solid foundation of information for investment and planning purposes.