For pulverized coal pyrolysis process, it is important to separate the coal dust from coal pyrolysis gas to obtain pure coal tar gas. However, it is difficult to remove the coal dust efficiently at high temperature. A two-stage coal dust removal system which consists of a cyclone separator and a dual-layer granular bed filter has been developed. Semicoke is selected to be the filter media of granular bed filter, because after the filtration process the mixture of semicoke and coal dust can be directly burned for power generation and the regeneration process of filter granules can be eliminated. A series of experiments were conducted to study the performance of this dust removal system and the impacts of temperature and tar gas on this system. The experiment results showed that semicoke performs better than silica sand as filter media and the dual-layer granular bed filter is more effective than single layer granular bed filter in this experimental condition. The best combination of the dual-layer granular bed filter is a 10-cm-thick upper layer filled with 0.83~1.25 mm filter granules and a 5-cm-thick lower layer filled with 0.38~0.83 mm filter granules. The results of this study indicated that the whole system is capable of removing coal dust from the mixture of coal tar gas and nitrogen gas even at 723 K, efficiency reaching up to 99.95 %.
