A compensation strategy to improve gas-solid heat transfer without sacrificing kinetic energy in a cyclone pyrolyzer

Abstract

The enhancement of the gas-solid heat transfer process is usually accompanied by an increase in kinetic energy consumption in a cyclone pyrolyzer. Unfortunately, in the current literature, there are few reports on how to improve the gas-solid heat transfer process without increasing the kinetic energy consumption. In response to these challenges, a compensation strategy was proposed to globally optimize the flow properties in cyclone pyrolyzer. Concretely, increasing the thermal resistance of the localized low thermal resistance region to compensate for the high thermal resistance region, achieving a more uniform thermal resistance distribution, thereby optimizing the overall flow and heat transfer properties. In this work, the exhaust pipe insert depth (S = 30, 45, 60, and 90 mm) was used to regulate gas-solid flow behaviors in a cyclone pyrolyzer. The heat transfer process and its control mechanism are systematically studied using the Computational fluid dynamics-Discrete element method (CFD-DEM). Results show that the extension of S increases the final temperature of the coal particles by 21.6 %, while reducing the pressure drop and kinetic energy consumption. Furthermore, by analyzing the gas-solid flow behavior, it was found that the extension of S can improve the gas flow field and synergy characteristics. These results are expected to provide theoretical guidance for improving the heat transfer efficiency in the cyclone pyrolyzer.