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Performance and Emissions Control of Commercial-Scale Biochar Production Unit

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Applied Engineering in Agriculture. 34(1): 73-84. (doi: 10.13031/aea.12375) @2018
Authors:   Mark A. Severy, David J. Carter, Kyle D. Palmer, Anthony J. Eggink, Charles E. Chamberlin, Arne E. Jacobson
Keywords:   Biochar, Biomass, Biomass conversion technology, Carbon sequestration, Forest residuals, Gasification, Pyrolysis.


Two commercial biochar production machines – a single-auger unit and a larger dual-auger version – were operated to evaluate feedstock specifications, biochar quality, throughput rates, and emissions profiles. Biochar was produced from woody biomass feedstocks of various species, contamination levels, comminution methods, and moisture contents. Feedstocks with ash content exceeding 15% dry basis or moisture content exceeding 25% wet basis were observed to decrease fixed carbon content of biochar and to increase the labor effort required to operate the machine. The dual-auger version of the machine was able to process 380 kg h-1 of biomass feedstock (dry basis) to produce 63 kg h-1 of biochar with a mean electricity demand of 4.5 kW. Average CO, propane, NOx, and SO2 emission rates from the flare of this machine were measured to be 160, 120, 51, and 43 g h-1, respectively, with total particulate matter (PM), PM10, and PM2.5 emission rates of 380, 40, and 4.5 g h-1, respectively. Results from these experiments indicate that high-quality biochar can be produced from a variety of feedstocks, including forest residuals, as long as the ash and moisture content are within the specifications. Future research and development should focus on increasing the throughput of the machine, implementing an automated control system to reduce the operational effort, and improving safety and product consistency.

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