Cyclone design comprising an inlet device having an inlet height (Hi) and an inlet width (Wi), a gas outlet pipe having a pipe diameter (Di) and a pipe penetration (P), a barrel having an upper barrel diameter (Db) and a barrel length (Lb), said barrel comprising a cylindrical volume on top of a conical volume, a solids outlet pipe (O), an inlet gas velocity (Ug, i) and an inlet gas flow (Q), characterised in that the ratio of the inlet gas flow to the square of the upper barrel diameter (Q/Db2) is higher than 0.5, preferably higher than 0.7, and lower than 1.5, preferably lower than 1.2 (m/s) and in that the barrel length to diameter ratio (Lb/Db) is higher than 3, preferably higher than 3.5, and lower than 6, preferably lower than 4.5.