Gas-Solid Heat Exchangers

Abstract

Gas-Solid particle heat exchanging is usually realized by direct contacting in a suitable medium such as packed, fluidized or spouted bed. It is also possible to utilize especially fluidized beds as an indirect contact type heat exchanger through the introduction of heat transfer pipe bundles. In the latter case heat exchange usually takes place between the bed and liquid flowing through the pipes. As the topic of this study is gas-solid heat exchange, indirect contact type heat exchanging application of fluidized beds are excluded. Thus solely direct contact heat exchanging between gas and solid particle medium will be the topic of this study. Due to strong mixing of particles and very large amounts of heat transfer surfaces achieved in fluidized beds, they offer high heat transfer rates. On the other hand packed beds offer similar advantages whereas spouted beds consisting of a central fluidized region and annular dense packing exposes a combination of the former two regimes. The common applications of the gas-solid heat exchangers are drying, adsorption, reactor engineering and quenching. Mainly two regimes namely packed bed and fluidized bed regimes will be considered for the analysis.