Law of conservation of energy
Thread Content
For the top condenser of the distillation tower (water-cooled), is there any inherent pattern regarding the temperature of the material after cooling and the temperature of the return water? Must the temperature of the material after cooling be higher than or equal to the temperature of the return water?
How can the temperature of a material be lower than that of the cooling return water? This violates the second law of thermodynamics
After the material is condensed, its temperature does not necessarily need to be higher than or equal to the temperature of the recycled cooling water; it can be made close to the temperature of the cooling water before entering the system. However, it is necessary to design sufficient heat exchange baffles for the cooling water to ensure that there is enough space for counterflow heat exchange. Such condensers require higher investment, so in terms of design considerations related to costs, it is generally preferred to choose a condensation temperature that is ≥ the temperature of the recycled cooling water
In actual operating conditions, the temperature of the red material is always higher than that of the return water
The return water temperature can be kept low; the heat exchanger can simply avoid temperature cross-over.
The attached figure shows two flow pattern arrangements for the heat exchanger: counterflow and parallel flow, qualitatively describing the temperature relationship between the cold and hot fluids