| 摘要 |
PURPOSE:To effectively suppress the redissolution of carbon dioxide and to heat supply water without precipitating scale such as Ca-sulfate by arranging a decarbonizing and/or degassing apparatus and a reverse osmosis apparatus for the pretreatment of supply water on the upstream side of a multiple-effect distiller. CONSTITUTION:A decarbonizing and/or degassing apparatus 2 and a reverse osmosis apparatus 3 for the pretreatment of supply water are arranged on the upstream side of a multiple-effect distiller 1. As a result, the greater part of the carbonate group dissolved in the supply water is degassed by the decarbonizing and/degassing apparatus and the greater part of Ca<++>, SO4<++> or Mg<++> becoming the scale component in the supply water can be removed by the reverse osmosis apparatus. By this method, the redissolution of carbon dioxide generated by the thermal decomposition of the carbonate group can effectively be suppressed in an evaporator and ultra-pure water can be obtained. Further, the supply water can be heated to about 125 deg.C or higher in the evaporator without precipitating scale such as Ca-sulfate and the evaporator can be made compact and maintenance cost can be reduced. |
