The tube connection issues in shell and tube heat exchangers
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In the tube side, the cooled medium (also water at 80-90 degrees) flows in from below and out from above; in the shell side, the cooling water also flows in from below and out from above. Is this okay? Does it affect the heat transfer efficiency? I remember that in the principles of chemical engineering, counter-current contact is supposed to yield better results, right?
In this way, the heat exchange efficiency is lower than that in counterflow, but if connections are to be made, it should be done in accordance with the process flow.
The flow pattern of hot and cold fluids can be chosen, mainly depending on the process requirements. If the process requirements cannot be met in co-current operation, counter-current operation should be considered, as it yields better results.
In the situation described by the poster, to improve heat exchange efficiency, counterflow should be chosen
The situation described by the poster is acceptable. The heat transfer efficiency depends only on the effective average temperature difference, and the effective average temperature differences for co-current and counter-current flow are not significantly different. However, counterflow can enable the hot fluid to achieve a lower exit temperature.
Counterflow allows the hot fluid to achieve a lower outlet temperature; if the temperature of the cooling water is 10°C, then as long as the heat exchange area is sufficient, the temperature of the hot water can be reduced to 10°C, which is not possible with co-flow!
I think whether a heat exchanger operates in counterflow or co-current mode cannot be determined by the way the heat transfer medium enters and exits the heat exchanger; it mainly depends on the flow direction of the two fluids – if they are in the same direction, then it is co-current flow； Difference means counterflow.
Counterflow should be chosen, haha. As for the choice between the tube side and the shell side, there’s no problem with that
On the high-temperature side, flow should be from top to bottom, while on the low-temperature side it should be from bottom to top; in addition to considering the effectiveness of counterflow, the effect of the retention zone also needs to be taken into account
The inlet and outlet connections are in the correct direction: for liquid media, flow is from top to bottom, and for gas media as well. The inlet connections in the upper part of the shell side are close to those in the tube side, while those in the lower part of the shell side are far away from those in the tube side; this arrangement ensures that the flow direction of the medium in the shell side is opposite to that of the medium in the tube side.
This is also acceptable; the inlet and outlet directions of the fluid in the heat exchanger are primarily determined by the process requirements. However, counterflow is generally chosen as it yields better heat exchange results.
It is best to have counterflow, with the cold-side fluid entering at the bottom and exiting at the top, as this helps to protect the heat exchanger
For heat exchangers of the same size, counterflow has a higher heat transfer efficiency. It’s best to do it in the reverse direction
Is the heat transfer efficiency of counterflow necessarily better than that of coflow? Maybe your process doesn’t require such good heat transfer? May I ask if the cooling water you export has any other uses? If it’s for some other purpose, maybe the design is correct? Design institutes generally don’t make such mistakes, right? If it’s gas exchange, then it’s a different story!
This works too; in actual production, it is arranged such that on the high-temperature side, flow is from top to bottom, while on the low-temperature side it is from bottom to top. This counter-current arrangement yields good results. Is this arrangement a requirement of the manufacturing process?
When it comes to heat exchangers, the efficiency of heat transfer needs to be taken into consideration; however, from the information I’ve seen, counterflow is considered to be the better option!
Such a method of takeover has a significant impact on heat exchange efficiency, and counterflow should be considered
If the requirements can be met and installation is straightforward, a co-current configuration can be chosen; in that case, using a counter-current configuration would make it difficult to connect the pipes
It mainly depends on the process flow; it’s not the case that the lower the outlet temperature, the better. Of course, the counterflow heat exchange efficiency is high! Many of the top condensers we produce are in the situation described by the poster
Counterflow heat exchange provides better results; if this is determined by the process conditions, then it’s also acceptable. The hot fluid enters from above and exits from below, while the cold fluid enters from below and exits from above. Special attention must be paid when phase change occurs