Rheological properties of several kinds of feedstocks for anaerobic fermentation and their influencing factors

In order to provide a theoretical basis for selecting apparatus and designing processes of anaerobic fermentation, rheological properties of six kinds of feedstock were investigated, and rheological parameters were evaluated at different total solid concentrations, temperatures and fermentation time. The experimental results showed that the six kinds of manures behaved like pseudoplastic fluid and followed the power law model, and the flow behavior index decreased with the increase of concentration. The viscosities of duck manure, cattle manure and chicken manure decreased linearly with the increase of temperature, and the flow behavior index increased. The viscosities of pig manure, sheep manure and rabbit manure reduced at first, and then increased. The calculated activation energy of duck manure, cattle manure and chicken manure were 8.018, 11.337 and 8.285 kJ/mol, respectively. With the processes of fermentation, the viscosity of duck manure declined in the basic trends and showed similar changes with total solids. The viscosities of pig, sheep and cattle manures showed an upward trend, and the change trends of chicken and rabbit viscosities were not obvious.