| 摘要 |
An evaporating apparatus includes an evaporator (E) for converting a liquid into vapor and a preheater (2) for heating the liquid before it is fed to the evaporator (E). A pump (6) for feeding the liquid to the preheater (2) and another pump (8) for pressurizing the liquid passing from the preheater (2) to the evaporator (E) are provided, where the former maintains the liquid at a saturation pressure with respect to a temperature slightly higher than a saturation temperature (to) at the preheater outlet, and the latter serves to raise the liquid pressure to a saturation pressure with respect to a desired evaporation temperature (t2). Rate of flow of a heating medium for the preheater (2) is controlled so that its temperature (tw3) is slightly higher than a liquid preheater outlet temperature (tex). Thus, in the preheater (2), the liquid temperature (tex) is maintained lower than saturation temperature (to), ensuring a greater amount of heat transfer by subcool boiling.
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