Co-pelletization of edible fungi cultivation residue and pine sawdust: The optimal variable combinations

Co-pelletization of edible fungi cultivation residue and pine sawdust would help reduce the problems of residue disposal and resource limitation of pellet production. The objective of this work was to obtain the optimal variable formulations for pellets production from blends of Flammulina velutipes residue and Pinus sylvestris var. mongolica Litv. sawdust. Response surface methodology was employed to design the experiments. A uniaxial piston-cylinder compression apparatus was used to produce pellets. The effects of variables of residue adding amount, moisture content, temperature, and pressure on responses of specific energy consumption, relaxed density, and Meyer Hardness were analyzed. Variance analysis of the data demonstrates that the differences between adjusted R-2 and predicted R-2 values are all within 0.2. The optimal variable combinations with residue content varying 0-40% were obtained according to the set response goals. Validation experiments were carried out using the same apparatus and relative percentage errors between the response predicted values and the experimental results were analyzed to improve the models. Most final errors were reduced below 10% indicating the high accuracy of the models. Further calculation of calorific value and ash content manifests that pellet performances could be improved by co-pelletization.