Study On Concentric Tube For Main Distributor In Circulating Fluidized Bed Heat Exchanger

Because of the non-homogeneity of particle distribution in the pipe bundle, which results in process instability and great energy consumption, the development of fluidized bed heat exchanger in industry field is restricted. Based on theories of branched pipe line and fluidization, the key problem is solved by a new type of distributor, which is the concentric tube as the main distributor. On the condition of perforated plate as pre-distributor, concentric tubes are fixed on the inlet of heat exchanger pipes. The combination of the pre-distributor and the main distributor is called as the combined distributor.The construction and principle of the main distributor were firstly introduced. The law of conservation of mechanical energy, material balance calculation and pressure balance relation were used to set up a model of main distributor for designing formula. After analyzing the model, all factors were found out to guide the experiment.Under the direction of the designing formula, the small cold model system and 2-dimensional cold model system were constructed for experimental study. Solid holdup and particle circulation rate which described the distribution quantitatively, were investigated in the small equipment. The feasibility of concentric tubes as the main distributor is validated. The coefficients of local resistance of main distributor were measured in order to obtain the relationship which expressed the relation among the coefficients of local resistance, the construction of main distributor and solid holdup. Therefore, the designing formula was accomplished and able to direct the design and magnification of main distributor in the future.