Control of Solid Mass Flow Rate in Circulating Fluidized Bed by a Pulsed Gas Flow

As a coal-fired power generation technology for further improvement of power generation efficiency of coal-fired power generation, exergy recuperation type coal gasification power generation technology, a triple-bed circulating fluidized bed, has been proposed. The authors analysed the flow characteristics of the triple-bed circulating fluidized bed, it has the flow characteristics of the riser and downer perform the proposed approach to representation by the equivalent circuit model. This equivalent circuit has the nature of the low-pass filter. A combination of the low-pass filter and the pulse voltage is used as a switching power supply. Then, we applied that the pulsed gas supply to the riser combined with a low-pass filter characteristics to control the particle circulation rate of the triple-bed circulating fluidized bed. We used an electric circuit simulator SPICE to calculation of circuit behaviour. Circuit constant is to use the value from the experiment, the input pulse height is set to 80 V. When the input pulse width is changed, the output current is changed depending on the pulse width. Moreover, when changing the density of the pulse, the output current is changing depending on the pulse density. This result by giving a pulsed gas supply to the riser, it shows the possibility controlling the particle circulation rate of the triple-bed circulating fluidized bed.