Abstract: Fluidized bed apparatus, comprising a circulating fluidized bed reactor with at least one outlet port at its upper part, wherein said outlet port allows a mixture of gas and solid particles exhausted from the fluidized bed reactor to flow into a number (n) of associated separators for separating solid particles from said gas, a number (n) of means to transfer said separated solid particles from said (n) separators into a number (up to n) of discrete fluidized bed heat exchangers (24.1, 24.2, 24.3), and return means to transport at least part of said solid particles back from said discrete fluidized bed heat exchangers (24) into the circulating fluidized bed reactor, wherein the number (up to n) of discrete fluidized bed heat exchangers (24.1, 24.2, 24.3) are mechanically connected to provide one common fluidized bed heat exchanger (24)mwith water cooled intermediate walls (24i) between adjacent discrete fluidized bed heat exchangers (24.1, 24.2, 24.3).