Abstract: The invention relates to a pipe (13) for conveying a condensable gas or a gas comprising condensable components, comprising at least one portion (15) inclined relative to horizontal. A ring (17) is accommodated in the portion (15) inclined relative to horizontal, which ring is joined to the pipe (13) by a first end face (21) in a liquid-tight manner over its entire circumference and whose diameter decreases towards a second end face (25) opposite the first end face (21), such that a space (27) is formed between the ring (17) and the internal wall of the pipe (13), the ring (17) is positioned in such a way in the pipe (13) that liquid condensing on the pipe wall flows into the space (27) between ring (17) and internal wall of the pipe (13), and an outlet (19), through which the liquid may flow out, opens into the space (27) through the wall of the pipe (13). The invention further relates to a device for carrying out mass transfer processes and to use of the device.