Fluidization in Cold Flow Circulating Fluidized Bed System

Abstract

Fluidized bed combustion (FBC) system is widely regarded as one of the most promising techniques for burning low-grade fuels and also to reduce the emission of atmospheric pollutants such as SO₂ and NO _x released during the combustion. The performance of a circulating fluidized bed (CFB) boiler is influenced by the mixing of gas and particles. A high mixing rate contributes to an effective distribution of reactants, whereas insufficient mixing can lead to hydrocarbon emissions. Therefore, an adequate understanding of the mixing behavior is important to ensure a high combustion efficiency and emission control. In this work, the cold flow CFB system containing rectangular cross section (150 × 300 mm) riser having a height of 2.1 m was fabricated in the Department of Energy and Environment Engineering, Quaid-e-Awam University of Engineering, Science and Technology, to study the fluidization of fuel particle and air at various flow rates. The riser exit has also been made of Plexiglas, which is useful in studying the end effects in rectangular cross section geometry. While conducting experiment, it was found that the pressure in the riser section increased as primary air flow rate was increased, and also the rate of circulation of solid particles increased.