Abstract
A nanofiltration experiment on skim milk up to a volume reduction factor 2 was conducted using 2-stage continuous equipment. The results were compared with the data obtained for the batch mode. During nanofiltration, the average total solids of retentate in continuous mode were higher than those in batch mode, but the content of Na, K and Cl in dry matter of product (de-mineralized and concentrated milk) was the same for both continuous and batch modes. A continuous operation experiment was also conducted at a temperature of 2-7 degrees Celsius, initial operating pressure of 1.5 MPa, and a fixed a volume reduction factor of 2.0. When this was done, the operating pressure rose by 0.1 MPa three hours after starting. This implies the possibility of safe long-time-operation.
