EW 520 then QR 4704 at Barcelona
Cologne → Barcelona → Porto
Timetable, Barcelona time
16:50EW 520 from Cologne at the gate
08:35QR 4704 to Porto leaves the gate
15 h 45 apart on the timetable, overnight
QR 4704 leaves 15 h 45 after EW 520 arrives on the timetable: more than half a day, so not a connection we count.