Abstract: A novel arrangement of cyclone and plenum assembly and support therefor wherein the plenum is a totally separate vessel and is suspended from the main vessel shell on pinned connectors to thereby provide for unrestrained vertical and horizontal movement. In turn, the cyclone weight or load is supported directly from the outer periphery of the plenum chamber in a manner to allow direct load transfer from the heavy cyclones directly upward through the brackets and pinned connectors to the main vessel shell. This arrangement which is in effect a floating plenum and cyclone combination, is connected to the vessel outlet line with a flexible bellows connection providing the necessary seal between the main vessel and the plenum. The use of relatively short radial bracket members on the outer periphery of the plenum chamber, to which the pivoted support links are connected, minimizes the length of the support beam to which the combined load of the cyclones and the plenum is applied.