Strange phenomena in heat exchangers
Thread Content
This post was last edited by blued simple life on 2020-6-5 09:44. Hello everyone, there is a condenser on one of the company’s production units (as shown in the diagram). In this condenser, the circulating water flows through the tube side (four tube passes), while the process fluid flows through the shell side. A rather strange phenomenon has emerged: if the object is divided vertically down the axis, the temperature of the left half is significantly higher than that of the right half (it’s not due to sunlight:P). In particular, it should be the case that the temperature in the central area of both the left and right halves of the casing is low, but in reality the temperature in the upper-central part of the left half is quite high, while the upper-central part of the right half has a normal temperature, being low. I wonder if any friends have encountered a similar phenomenon? (The circulating water flow rate is very low). Since some friends don’t understand how to distinguish between left and right as I described, I found a heat exchanger shell online and illustrated it as follows (not cut radially :)): The actual structure of the heat exchanger is shown below:
The flow rate of the cooling water in the four-pass system is still relatively slow; if the outlet side is also the inlet side, it’s reasonable that the heat exchange in this section isn’t sufficient at first
Water is on the tube side, entering from below and exiting from above； Gas enters at both ends of the shell side; non-condensable gas exits from the middle of the upper part, while condensate exits from the middle of the lower part. A slow water flow rate is indeed not very reasonable, but the problem now is the significant temperature difference between the left and right halves, which is hard to understand; normally they should be the same.
The temperature of the circulating water on the right side is low, resulting in a greater average temperature difference; it seems fine that the temperature of the exhaust gas is low. Also, regarding what you mentioned – is it the gas or the water that is lower on the left side compared to the right side? If it’s gas, how can you tell without looking at the shell side? If it’s water, the inlet temperature is low; it’s fine if the right side is lower as well
The temperature of the circulating water on the right side is low, resulting in a greater average temperature difference; it seems fine that the temperature of the exhaust gas is low. Also, regarding what you mentioned – is it the gas or the water that is lower on the left side compared to the right side? If it’s gas, how can you tell without looking at the shell side? If it’s water, the inlet temperature is low; it’s fine if the right side is lower as well
How does the cooling water flow in a four-pass system? Are you sure it’s not caused by high water temperature?
Look at your process: since a steam jet pump is used, are both the shell sides of the heat exchanger under negative pressure? Differences in negative pressure on the two sides could be caused by factors such as non-condensable gas circuits on those sides, which is why the temperature of the condensate water coming out of each side also differs. You can try measuring the pressure on each shell side.
There are reasons behind the requirements of the process package; there’s no need to worry about it.
We went to the site and touched the heat exchanger shell.