Abstract
The effects of aeration on the aerobic fermentation and drying process were investigated through experiments widely ranged for aeration rate which was represented by superficial velocity. While our last paper (reference 3) mainly described the experiment at the aeration rate of 7.32 [cm/min], this paper reported the results of experiments ranged from 0.18 to 40.3 [cm/min] for the aeration rate and uniformly controlled for the other conditions.
Twelve examples of experiments (Table 1), reasonably distributed for aeration rate were analyzed, using the computed estimation method confirmed its effectiveness in the previous paper. The effects of aeration rate on the material temperature rising were shown in Fig. 3-Fig. 5. The heat losses, caused by the differences between central temperatures and the outside temperature, from the side wall or from the upper covering plate varied, when the aeration rate was widely changed. We checked these relations, and improved the compensation method of the computed estimation by substituting the formulas (1)-(4) for the formulas (3)-(6) of the previous paper. After the improvement, calculations were very close to experimental values shown in Fig. 2.
Using the computed estimation method, some important characteristics of the aerobic fermentation and drying process, such as dry matter decrease, water decrease, air ratio and so on, were grasped in detail as to the lapse of time as Fig. 6-Fig. 10. Furthermore, the criteria of optimum aeration rate were presented.
