FIRST EXPERIENCE IN OPERATION OF COLD MODEL OF FB-CLC-SF (FLUIDIZED-BED CHEMICAL-LOOPING-COMBUSTION SOLID-FUELS) FACILITY

摘要

The experiences with a cold model of dual fluidized-bed unit designed for chemical looping combustion of solid fuels (FB-CLC-SF) are presented in this paper. The constructed facility combines two different type reactors. The first one, which is the air reactor (AR) is operated in a regime of fast fluidized bed, whereas, the second one, which is the fuel reactor (FR) works under bubbling fluidized bed conditions. However, the integrated reactors make the whole construction being a CFB-type (Circulating Fluidized Bed) unit. The facility is made entirely of transparent material. This feature supports effectively the measurements, which enables to conduct the comprehensive studies in the field of investigations. During this research, the air was used for bed fluidization in both reactors. As an inventory, the glass beads were employed, since they size and density (d_p = 100 -200 μm, ρ_s = 2450 kg/m~3) relate closely to the properties of oxygen carriers developed concurrently in the project, whereas they are significantly less expensive and friendlier in use. Over a dozen ports for pressure measurements are provided along the main circulation path of the solids. These experimental data enable to determine the pressure balance around the whole CFB loop, which becomes the starting point for further studies. The cold simulations of solids flow demonstrate the conditions that are expected in a case of the hot test rig operation, which remains under construction. Therefore, the main goal of this work is to establish the operating conditions that consider both: a smooth fluidization throughout the FB-CLC-SF unit and an efficient oxidation/reduction of oxygen carriers in AR and FR, respectively. The effect of gas velocities in air- and fuel reactor on the process performance found to be essential.