Acoustically enhanced cyclone collectors offer the potential of achieving environmental particulate control standards under pressurized fluidized bed combustion (PFBC) conditions without the need for post turbine particulate control. The objective of this research program is to extend acoustic agglomeration technology from the laboratory scale up to the sub-pilot scale. The effects of high intensity sound on the agglomeration of fly ash particles are being investigated in a simulated PFBC effluent stream. The test facility consists of a variable residence time acoustic agglomeration chamber with a vitiating air preheat combustor, an ash injection system utilizing an auger feeder, a natural gas fired pulse combustor sound source, and a two-stage high temperature, high pressure cyclone. Fly ash for these tests has been obtained from the TVA (Tennessee Valley Authority) Shawnee Station circulating fluidized bed combustor (CFBC), as well as the Nucla CFBC, and Tidd PFBC. Acoustic agglomeration tests are underway.
The acoustically enhanced cyclone collector is being evaluated with two distinct goals in mind: 1) determine the effects of the major operating parameters on acoustic agglomeration efficiency, and 2) optimize the agglomeration system performance for maximum particulate removal efficiency. The data obtained during these tests will provide direct information on the effects of sound intensity and frequency, particle residence time, ash loading, and pressure on the enhancement of cyclone collection efficiency with acoustic agglomeration. These data, in conjunction with results from an acoustic agglomeration computer model will be used to evaluate the economic and engineering feasibility of an acoustically enhanced cyclone collector for a full scale pressurized fluidized bed combustor.