Cream separator performance was evaluated by measuring the separation yield of skim milk, cream and separator slime; separator productivity and efficiency at different operation speed and different temperatures. The energy consumption and operation costs were also determined. Centrifugal separation process was simulated and the model results were tabulated and discussed. The most important results indicated that the skim milk separation yield ranged from 84.5-89.98%, cream ranged from 4.6-7.9%, and the separator slime ranged from 0.05-0.18% from the whole milk at different milk temperatures and rotational speeds. The separation time decreased by increasing both rotational speed of the separator and the milk temperature. The results indicate that the separation efficiency ranged from 94 to 97 %. The productivity of the cream separator increased from 128.00 to 165 kg/h at different operational speeds. The specific energy increased from 0.825 to 1.117 kW.h/Mg at 33 oC , from 0.790 to 1.011 kW.h/Mg at 38 oC and from 0.773 to 1.011 kW.h/Mg at 43 oC milk temperature, respectively. While the specific energy decrease with increasing the milk temperatures from 0.825 to 0.773 kW.h/Mg at 4000 rpm, from 1.053 to 0.978 kW.h/Mg at 4500 rpm, from 1.130 to 1.052 at 5000 rpm and from 1.117 to 1.011 kW.h/Mg at 6000 rpm the cream separator speeds, respectively. The chemical composition and microbiological changes due to separation of the separated products were not significant at different treatments under study. The model results indicated that the separation capacity (equivalent settling area, m2) increased with increasing the separator rotational speed, while, it decreased with increasing the milk temperature. The centrifugal velocity, flow rate and critical diameter increased with both rotational speed and milk temperature. The time of separation decreases with increases the both rotational speed and milk temperature. Grade efficiency decreased with increasing the rotational speed of the separator. |
