A fluid bed reactor is configured to process a reactive material to form one or more products. The reactor includes a reaction vessel defining a compartment configured to receive the reactive material. Attached to the reaction vessel is at least one heat transfer module. Each heat transfer module includes a pulse combustor and an associated acoustic chamber. The pulse combustor has at least one tailpipe that terminates in its associated acoustic chamber. Flue gases exiting the tailpipe(s) pass from the acoustic chamber, through a wall separating the acoustic chamber from the reactor vessel and into heat transfer tubes that protrude into a compartment of the reactor vessel. Feedstock inlets are configured to introduce the reactive material into a region that is vertically between the first and second clusters of heat transfer tubes. The heat transfer tubes have an annular construction such that the flue gases pass through an inner shield tube in a direction away from the wall, turn around, and return in a direction towards the wall. The gases are then directed to a manifold from which they ultimately exit the device. Cooling by water or another heat transfer fluid may be provided to the tubes to facilitate integrity of the materials and joints of construction. The reactor may be controlled such that the fluid bed selectively is operated either in the bubbling bed regime or in the turbulent fluidization regime.