Problems with the balance line of the tower top condenser

Actually, either one will work. There is a slight pressure difference between these two points; it’s due to the resistance of the condenser equipment. Doesn’t the condenser also have a gas outlet? Usually, it’s connected to the pipe at that outlet

Thank you. Now, I’m thinking that if there’s a high pressure drop in the equipment at the gas inlet, this line might short-circuit; instead of passing through the condenser, the gas should go directly into the tank. It would be better to connect it to the top of the tube box, so that the condensate can be used to condense the non-condensable gases once again

It’s a very common design; there shouldn’t be any doubts about it. The balance line No. 3 can only be installed on the condensate side, that is, according to the scheme in your first diagram. The reasons for this are quite clear to you; the consequences of using a shortcut can be severe, especially when design work is not done carefully or when there is a lack of experience. It is necessary to carefully calculate the diameter of this balance line, and there are also many considerations regarding the piping used. . . It is best for the temperatures of the media on both sides of the balance tube to be identical; if one side is higher and the other lower, problems will arise during actual operation. . . Actually, the simplest and most practical solution is to not make Line 2 too thin – design it as a pipe with one half used for gas flow and the other half for liquid flow. This approach is simple, practical, and requires no extra hassle. Of course, this is true provided there is no need for measurement. If it’s necessary to install a flow meter on the liquid flowing in Line 2 in order to measure things like the reflux ratio, then a U-shaped bend will be required for Line 2, and it won’t be possible to use a pipe with two separate flow channels.