There will be some frictional pressure drop over the lines between column and aircooler, between aircooler and watercoolers, and between watercoolers and drum.
But there will be some pressure gain due to staic pressure of the mixed phase (gas+liquid) between between aircooler and watercoolers, and between watercoolers and drum.
You would need to do calculations to know the exact numbers, but normally the piping pressure drop would be in the order of 0.1 bar.
The pressure drop over the aircooler and over the watercoolers will however be by far the biggest factor in the pressure difference between column top and drum.
If this is an existing system you should be able to obtain column top pressure and drum pressure from the DCS.