Heat exchange area of shell-and-tube heat exchanger
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Overview: A total of 2 condensers are considered, with the aim of completely cooling the ethanol that could not be condensed in the previous stage using circulating water. The condensation takes place under vacuum conditions, and the cooling medium used is water at 7 degrees Celsius. The vacuum pumps are dry pumps, each equipped with a buffer tank; the condensers are installed in front of these buffer tanks. Tubular heat exchangers are planned to be used for all of them. I. For condenser A: It is known that the flow rate of uncondensed ethanol is 600 kg/h, the inlet temperature of ethanol is 40–55°C; the operation mode is vacuum concentration. The diameter of the vacuum tube is DN150, the inlet temperature of the cooling medium is 7°C, and the ethanol concentration is 88%. Ethanol flows through the shell side while the cooling water flows through the tube side. Determine the heat exchange area of the heat exchanger ； Cooling water flow rate ； Check whether the area of the heat exchanger channels is sufficient. II. For condenser B: It is known that the flow rate of uncondensed ethanol is 2000 kg/h, the inlet temperature of ethanol is 40–55°C; the operation mode is vacuum concentration. The diameter of the vacuum tube is DN100, the inlet temperature of the cooling medium is 7°C, and the ethanol concentration is 88%. Ethanol flows through the shell side while the cooling water flows through the tube side. Determine the heat exchange area of the heat exchanger ； Cooling water flow rate ； Check whether the area of the heat exchanger channels is sufficient.
For a vacuum condenser, at the very least, the inlet pressure should be provided, right? This is very important! Are there also the composition and names of non-condensable gases? This is also very important. What about the material?
The pressure is set at -0.08 MPa (gauge pressure); no non-condensable gases are planned to be used. The material used is stainless steel. Thank you for your attention! Could you provide some guidance on how to solve this problem?
Without non-condensable gases, how can it be designed? ? Should it be calculated with constant non-condensable gas? What about none? !
I’m sorry; as this is my first time dealing with this, the owner refuses to provide detailed information, so I can only do a preliminary and simple calculation. . . . . .
Non-condensable gases have a significant impact on the heat transfer coefficient; it is impossible to calculate it without taking them into account.