METHOD AND SYSTEM FOR CLEANING OFF GAS

PROBLEM TO BE SOLVED: To provide a method for cleaning off gas that can be optimized without ruining the reliability of the operation.SOLUTION: There is provided a method in which off gas is cleaned by an adsorption step, in the adsorption step, off gas (5) is introduced into reactor (1), is contacted with an adsorbent (8) for the adsorption of a contaminant, and is assigned to a reactor (1), and solid particles are separated from the off gas (5, 13) in a solid separator (2) that is present downstream of a direction of flow of the off gas (5, 13), and at least a part of the solid particle is returned to reactor (1). In the method, the at least one of the solid part returned to the reactor (1) is, before returning to the reactor, cooled by transmitting the thermal energy from the solid particles to a cooling medium (25) of the fluid in a heat exchanging element (23) through the solid surface of at least one heat exchanging element (23).