Enhancing Oxidation Process in Chemical Looping Combustion Applying Jet Fountain Fluidized Bed. (Dept. M ( Power ) )

Abstract

Chemical-Looping Combustion (CLC) has emerged as a very promising combustion technology for power plants and industrial applications with inherent CO 2 capture. CLC avoids the energetic penalty present in other competing technologies. The technology basis is to transfer oxygen from air to the fuel by means of a solid oxygen-carrier avoiding direct contact between fuel and air. It consists of two successive reactions, oxidation and reduction, in two interconnected fluidized beds. The aim of the current work is to enhance the oxidation process by applying jetting fountain fluidized bed. A jetting fountain fluidized bed reactor has been designed, fabricated and installed to carry out the experimental work. It has 105 mm ID and 4000 mm height. Activated ilmenite has been used as oxygen carrier. During the tests atmospheric air is fed through an ilmenite bed that reacts with oxygen. The oxygen concentrations are measured after the bed to estimate the quantities of oxygen that combined with bed materials. The influences of operating conditions including bed temperature, fluidization velocity, jet air ratio and jet orifice height on the process effectiveness have been studied. The findings of the present work indicate that the jetting fountain fluidized bed is more effective in ilmenite oxidation where the oxidation conversion rate increases and the time required for full conversion reduces. Applying jetting fountain configuration enhances gas solids contact and improves the interphases mass exchange between bubbles and emulsion. The oxidation conversion rate was found to improve with bed temperature and fluidization velocity. On the other side, studying the influences of jet air ratio and jet orifice height demonstrate that there is an intermediate value at which the oxidation process records an optimal.