The goal of this project was to investigate the pyrolysis of hazelnut shells for our sponsors, Clark Farms and Cascade Foods. Currently, these sponsors produce roughly 10,000 tons of hazelnuts. Hazelnut shells are a by-product within this process that are sold at $7.50 per ton. Pyrolyzing hazelnut shells produces a valuable product called biochar. Biochar is primarily used as a soil amendment, where its porous structure increases water and nutrient retention. Another benefit of biochar is that it is environmentally friendly as it is a form of carbon sequestration. On the economic side, biochar can be sold for $1000 - $2000 per ton.
To undergo pyrolysis, the target biomass must undergo thermal decomposition without the presence of oxygen. This separates the biogas compounds from the biomass, leaving behind carbon-rich biochar. To accomplish this process, we decided to use a rotary kiln reactor sourced from Beston Machinery.Their clean and safe process will produce roughly a 33% yield of biochar with a capability of processing up to 3 tons of feedstock per hour. Fuel such as propane is only required to preheat the reactor. The biogas produced from this process will be used to sustain the heating process. The reactor includes several post-processing units to keep exhaust gas emissions environmentally friendly and allows the biochar to be safely handled directly after discharge.
Another benefit of the reactor is that it can potentially be expanded to include other operations such as drying whole hazelnuts or roasting hazelnut kernels. Typically, Beston Machinery includes a drying unit if the feedstock is not adequately dried. This unit utilizes the hot exhaust gas coming out of the rotary kiln reactor to dry the feedstocks. Therefore, the unit can be repurposed to perform one of the aforementioned operations to further increase the energy efficiency of the process.
