Seeking a solution for heating air using a steam heater
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Seeking a solution for heating air using a steam heater. Currently, there is incoming air with a flow rate of 65,000 Kg/h, a temperature of 130°C, and a moisture content of 0.015 Kg/Kg. This air needs to be heated to 255°C using a finned steam heat exchanger. The steam used is superheated steam at 310°C and 8 MPa. What is the required heat exchange area? What will be the temperature of the condensate water? How should it be handled? I request experts on steam heat exchangers from the Haichuan Forum to provide a solution. Thank you! ! !
A simple approach is to contact the manufacturer directly, but be sure to clarify your requirements; box-type heat exchangers could be considered. Here are two suggestions: 1. The steam pipes should have a certain slope to facilitate the flow of condensate and prevent flashing. 2. Welding must be used between the pipe and the tube sheet; expansion jointing is not allowed. Due to the large volume of gas, the pipes vibrate intensely, which can easily cause cracks near the welds of the pipes. The above are my personal experiences.
What is the operating pressure of the air? If it is air from a fan, then a slight positive pressure is sufficient; in such cases, a conventional exchanger with external fins is recommended. For compressed air, an exchanger with internal fins is advised (in this case, air flows inside the tubes while steam condenses outside them, resulting in a higher heat transfer coefficient). As for the steam outlet temperature, it is generally sufficient to design it with a slight subcooling. Additionally, since the temperature in this operating condition is high, attention should be paid to thermal stress effects during design.
I would like to ask again: can the above conditions be met? What is the process required for pipes and valves? Thanks first