May I ask if the non-condensable gases from the primary condenser, along with the primary condensate, can be fed into the secondary condenser? ?

1. Condensate gas from stage 1 should not be discharged into stage 2, as this may lead to excessive load and poor gas-liquid mixing in the pipelines and condenser； 2. Based on the nature of your process, it is not recommended to do this

What would be the best way to do it? ?

1. May I ask if the non-condensable gases in the primary condenser, along with the primary condensate, can be fed into the secondary condenser? ? ? Of course, as long as there are enough pipes and this doesn’t cause poor flow of gas and liquid. Secondly, doing this will require an increase in the load on the secondary condenser. Originally, only the gas phase needed to be condensed, but now the liquid phase is also further supercooled. Finally, it is necessary to check whether your process requires the condensate to be supercooled to such a low temperature. It’s a waste if it’s not needed! ! 2. May I ask if it is possible to seal the non-condensable gas outlet of the primary condenser, so that non-condensable gas can only be discharged from the secondary condenser? ? It’s okay for the liquid to come out from the bottom; have you ever seen exhaust gas coming out from the bottom as well?

The heat load due to liquid-phase condensation is not high, and the amount of non-condensable gases is also small; it mainly consists of saturated vapor pressures

It’s not high, it’s not big; you can just do the math by yourself

It should be possible. Leaving aside the possibility of operational issues for now, there is likely to be a buffer tank in the lower part of these heat exchangers, which essentially provides pressure control (pressure relief functionality). So it should be fine. Only in cases where there is a large amount of non-condensable gas during the initial operation of the system might it be necessary to consider making adjustments to the exhaust piping of the heat exchanger

If your secondary heat exchange area is large enough, it’s possible

First, you need to figure out what the function of this secondary condenser is In a process design like the one shown in the figure, stage 1 is generally considered to be condensation and stage 2 to be cooling. In that case, allowing the gas phase from the first-stage condenser to flow into the second-stage cooler will increase the load on the second stage, unless this additional load has been taken into account when calculating the heat exchange area; in such a situation, it is necessary to enlarge the outlet pipe for the liquid from the first-stage condenser ； If the temperature of the liquid obtained from the first-stage condensation already meets the process requirements and no further cooling is needed, and if the second stage is used solely for condensation purposes, then the connection method of the second-stage condenser is incorrect; the gas phase after the first-stage condensation should be fed into the second-stage condenser, with the latter being used for condensing the exhaust gases. Considering the boiling point of dichloroethane, there is not much of a problem with condensing the water in the primary circulation system; the secondary system should be used for condensing exhaust gases, and chilled water is more suitable for cooling purposes, for reference.

Isn’t your secondary condensation meant to cool further the air that hasn’t been cooled in the primary stage? ?

It’s possible, but it will reduce the efficiency of the secondary cooling; the liquid that enters will form a liquid film, which significantly lowers the heat transfer coefficient!