Abstract: Method and a device for controlling the temperature of a reaction carried out within a vessel in a fluidized bed containing solid particles which can be entrained with the smoke and then recovered in a separating device and recycled into the fluidized bed after passage through a heat exchanger where they yield up their heat. The flow of particles separated from the smoke is divided into two parts, a hot part recycled directly into the fluidized bed and a cool part constituted by particles taken up at the outlet of the separating device and passed into the heat exchanger to constitute a reserve of cold material which can be mixed with the hot part before reinjection into the fluidized bed, the relative flow rates of the hot particles and of the cold particles being regulated so as to control the flow-rate and the average temperature of the flow of particles recycled into the fluidized bed for maintaining at the desired level the reaction temperature in the midst of the latter.

Abstract: Method and apparatus for regulating the heat transfer coefficient between a granular material and an exchange surface inside a heat exchanger in which a descending flow of a charge of material is arranged in the form of a mobile bed in contact with an elongated exchange member extending between lower and upper levels of the tank of the exchanger. The latter is provided with injection means for a gas into the charge of material. The flow conditions of the gas passing through the charge from below upwards are regulated so that the ascending flow speed is initially less than, at the base of the tank, the critical fluidization speed and then increases gradually to reach such critical speed at an adjustable level comprised between the lower and upper levels of the exchange member. The invention is especially applicable to heat exchangers used for cooling a granular material and/or for the heating of a heat transfer fluid.