Experiment study on collection and heat transfer characteristics of hot gas with coagulative particles flowing through a fixed granular bed with embedded heat exchange tubes

The collection and heat transfer characteristics of hot gas with coagulative particles flowing through a novel fixed granular bed with embedded heat exchange tubes are experimentally investigated. The NaCl dust is used as coagulative particles, and the SiO2 dust is used as the solid particles to replace the NaCl for comparison. The experimental results show that the high collection efficiency can be achieved earlier for the coagulative particles than the solid particles, but the corresponding pressure drop is larger. In the initial stage of filtration, the overall heat transfer coefficient is higher for the coagulative particles than the solid particles, which increases with the rise of the inlet particles concentration. However, in the later stage of filtration, the overall heat transfer coefficient is lower for the coagulative particles than the solid particles, which increases while the inlet particles concentration decreases. The pressure drop caused by the coagulative particles increases with the decrease of the gas velocity and the rise of the inlet particles concentration. This novel structure can realize the high collection efficiency of > 98% and the high waste heat recovery efficiency of > 70% simultaneously.