Performance of hot-gas cleanup technology for clean coal processing

Abstract The integration of advanced coal-based power generation systems with hot-gas cleanup technology endows the former with higher efficiency and reduces their environmental impacts. Syngas from coal gasification or flue gas from combustion contains dust particulates that must be eliminated before the raw gas is burned in gas turbines to protect the turbine blade and control particulate emissions. The present work attempts to provide a general understanding of moving granular bed filters (MGBFs), which are regarded as a promising technology for hot-gas cleanup, and proposes a filtration technology for application to near-industrial environments. An experimental method was established to investigate the filtration processing of dust particulates under various operating conditions. The experimental facility included an air fan, two-stage gas heaters, a screw feeder for dust particulates, a measurement system to detect the size distribution of dust particulates, a filter granule supply device, a rotary valve, and an MGBF filled with filter granules. The collection efficiency of the MGBF was assessed at different temperatures ranging from room temperature to 500 °C and granular mass flow rates of 300–1500 g/min under a fixed filtration superficial velocity of 2100 cm/min and dust concentration 7500 ppmw. Variations in the outlet concentration and size distribution of dust particulates were measured to evaluate the dynamic characteristics of the cleanup process. Results revealed that an optimal mass flow rate must exist for high collection efficiency under specific operating temperatures. In addition, important design constraints were identified for the successful operation of the proposed MGBF system. The findings indicated that the proposed design could be useful in different cross-flow filter systems for gas cleanup. This work lays a solid foundation for future research on clean coal processing.