Two Crumbler Modules in a Tower Arrangement

Techno-Economic Analysis of Forest Concepts, LLC Crumbler® Operated at Proton Power to Process Crumbles® from Hardwood Chips

Abstract 

Developing cost-effective methods for processing biomass into an economic biofuel product is critical to the success for the bioenergy industry in the United States. Size reduction and drying of the material, where used, are two of the most costly and energy-intensive operations that are undertaken during preprocessing. Reducing the energy required during these two phases will lower the cost of processing and ultimately reduce the overall cost to the final user. 

In an effort to lower the cost for size reduction, Forest Concepts, LLC has developed a rotary shear for the comminution of biomass feedstocks. Forest Concepts has called this rotary shear the Crumbler®, which uses intermeshed rotating disks that shear the material rather than using impact to reduce the particle size of the materials. Forest Concepts, LLC has teamed with Proton Power, Inc., located in Lenoir City, Tennessee, to set up a pilot plant that uses the Crumbler® to produce roughly 1/4-inch crumbles that ultimately feed a renewable diesel plant in Rockwood, Tennessee. INL was contracted to test Crumbler® performance and provide a techno-economic analysis of the process. 

This demonstration used chipped (roughly 2-inch) hardwood trees, harvested locally near the Rockwood facility. Following the chipping process, a two-stage Crumbler® process was used to size-reduce chips to approximately 1/4-inch particles. The material produced from the Crumbler® (“crumbles”) is normally dried prior to feeding a bank of “CHyP” engines operated at Proton Power to make renewable diesel. Some of the processed crumbles were shipped to INL to be dried using the Biomass Feedstock National User Facility (BFNUF) process demonstration unit (PDU) rotary drier to measure the energy required to dry the crumbles to less than 10% moisture content. Additionally, raw chips were shipped to INL and dried prior to hammer milling to compare the two methods and provide data for the techno-economic analysis. 

About the Publication 

Yancey, N.A., D.S. Hartley, D.N, Lanning and J.H. Dooley, J. H. (2019). Idaho National Laboratory, Idaho Falls, ID.

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