Heat exchange area of the heat exchanger
Thread Content
This post was last edited by luojiahui on 2016-7-7 08:29. A single condenser is designed to completely cool the ethanol that could not be condensed in the previous stage using circulating water; the condensation takes place under vacuum conditions, with water at 5 degrees Celsius being used as the cooling medium. The vacuum pumps are dry pumps, and each pump is equipped with a buffer tank. The condenser is installed in front of these buffer tanks, and it is now being considered to use shell-and-tube heat exchangers. Given: The flow rate of uncondensed ethanol is 500 kg/h, the inlet temperature of ethanol is 45–55°C; the operation mode is vacuum concentration, the diameter of the vacuum tube is DN100, the inlet temperature of the cooling medium is 5°C, the ethanol concentration is 90%. 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.
I’m not sure why tubes are considered first; plate heat exchangers are also a good option – they have mature technology, require less space, and offer high efficiency. For something like your case, around 40 square meters should be sufficient with a flow rate of about 30 cubic meters per hour. I’m not good at calculating for tube heat exchangers; sorry about that
Spiral-wound condensers are also a good option, but their price is a bit high; you will need a manufacturer specialized in condensers to provide you with an estimate. They have a set of formulas that can be used to work it out. I’m not sure where you purchased your dry vacuum pump.
The last edit to this post was made by wiseboy on 2016-7-15 at 22:35. After talking so much about \"vacuum\" and emphasizing it over and over again, he still didn’t mention what the pressure level is. Scientifically speaking, whether it is a vacuum or high pressure, both are expressed in terms of pressure. It’s not true that there is no pressure in a vacuum; moreover, there are different levels of vacuum, and accordingly the pressure varies as well – not all vacuums are the same. You just need to provide the pressure. For such a question, with so many posts preceding it, it’s completely impossible to be useful.