Shell-and-tube heat exchanger, method of exchanging heat and use of heat exchanger

A shell-and-tube heat exchanger for exchanging heat between a tube-side fluid and a shell-side fluid comprising:

• a first tubesheet;
• a second tubesheet;
• a shell body that is fitted with a shell-side inlet nozzle, opposing terminal ends of the shell body bordered by the first tubesheet and the second tubesheet;
• one or more heat exchange tubes that extend through the shell body from the first tubesheet to the second tubesheet;
• and
• a spiral baffle following a helical trajectory with its center of rotation substantially aligned with a center line of the shell body, the spiral baffle arranged to provide a helical flow path through the shell body downstream the shell-side inlet nozzle towards the first tubesheet;
• and
• an outlet collector pipe that extends substantially coaxially within the shell body and that supports the spiral baffle along its length, such that the helical flow path is guided along an outer surface of the outlet collector pipe,
• wherein the outlet collector pipe is mounted to and passes through the second tubesheet, and
• wherein the outlet collector pipe is separated from the first tubesheet by a gap downstream the helical flow path to allow the shell-side fluid (FA) to enter an inlet of the collector pipe, which collector pipe inlet faces the first tubesheet across the gap, and to exit the shell body via a shell-side outlet nozzle provided on a terminal end of the outlet collector pipe opposite to the collector pipe inlet.