| 摘要 |
During a heat treatment in continuous flow of a product mixture consisting of a liquid containing solid particulates, the mixture is heated to a certain desired temperature in one or more heat exchange sections, held at this temperature in a heat-holding section for a certain time, and then cooled to the desired end temperature in one or more heat exchange sections. The residence time of the solid particulates in the heat-holding section is regulated separately and indepedently of the residence time of the liquid in the heat-holding section, while the solid particulates are constantly flowed round by the liquid. If there are solid particulates of various sizes in the liquid, the residence time of the various size fractions of solid particulates is regulated separately depending on the size of the solid particulates in a particular fraction. With this fraction-specific heat treatment it can be achieved that both the solid particulates of differing size and the liquid in the product mixture acquire a minimum required processing value, while at the same time it is prevented that one or more of the size fractions of solid particulates or the liquid is exposed to a high temperature for an unnecessarily long time, which can lead to detoriation of the quality of the product mixture. The device for carrying out the process comprises a heat-holding device (8) with one or more retaining devices (23, 24, 25). Each retaining device (23, 24, 25) is designed for retaining solid particulates of a certain size and larger during a certain time and allowing the smaller particulates and the liquid to pass. |
