I have a chemical reactor producing a humidified stream of hydrogen gas and I need to cool it down to near ambient temperature using a heat exchanger, say 25 degrees Celsius.
Within the reactor I measure a gas temperature of 70 degrees Celsius and 100% relative humidity. In the lab I measure a gas flow rate of 10 liters per minute using a calibrated mass flow controller after the gas passes through a jacketed reflux condenser, a water trap, and a tube of silica desiccant. Between the mass flow controller and the silica gel I measure a temperature close to ambient and a relative humidity of 40%.
How would I size an off-the-shelf air cooled heat exchanger to create the same level of gas cooling as the reflux condenser? The silica gel is only there to protect the mass flow controller, I would be okay with 95% relative humidity hydrogen as long as the temperature is near ambient.
In my mind I think I could purchase any small, cheap air cooled heat exchanger off Amazon but I'd rather try to approach the problem analytically. I plan on having a water trap after the heat exchanger to catch the condensed water vapor.