| 摘要 |
An apparatus used in a forced circulation evaporation process for concentrating process solutions capable of forming incrustations, eg. sugar solutions from the production of sugar or liquors from pulp mills, contains a centrifugal pump (3), a vertical multi-pass heat exchanger tube (2) located on the pressure side of the pump and a separator (1) positioned at a higher level than the heat exchanger.The vertical distance between an imaginary horizontal plane (reference plane 1) through the pump and an imaginary horizontal plane (reference plane 0) through the outlet of liquid into the separator is greater than the sum of the following values (a)-(d) minus value (e) : (a) equilibrium pressure in the process solution (htwi [mvp]) in the liquid film found next to the inner heat exchanger tube wall at the given temperature for the tube wall ; (b) total pressure drop (hfvx [mvp]) for the flow of liquid through the heat exchanger ; (c) sum of the pressure drop in a pipe between t he pressure side of the heat exchanger and the separator and the one-off losses occurring between the pressure side of the heat exchanger and the separator (hfroer [mvp]) ; (d) heat exchanger tube length (htub [m]) (e) the equilibrium pressure in the separator (havsk [mvp]), as defined in the following equation : |
