Testing of a Spouted Bed Reactor for Thermal Desorption of Mercury Compounds in Coal

Abstract The topic of this thesis is coal pre-treatment for mercury and sulfur removal before combustion. Mercury is a neuro toxic impacted in health issue, and is targeted by strict environment regulations. Thermal desorption was used in this investigation, since mercury exists in coal as different mercury species, which can be released at different pre-combustion temperatures. To achieve the thermal desorption process, two different kind of spouted beds, provided by the Advanced Cooling Technologies (ACT), Inc. were tested at the Lehigh University Energy Research Center. One is a baseline spouted bed with one central flow inlet, and the other apparatus consisted of a new design called multiple path spouted bed with eight flow channels. The experiments, carried out by the author of this thesis, targeted the highest mercury removal efficiency. Experimental parameters were selected and discussed in this thesis. Bituminous coal with a size of 4 mm top size was used as experimental material. Operation conditions were 300℃ for temperature and 27.5 m/s for air flow rate. The results of the experiments show that the multipath design has a better performance on both mercury and sulfur removal than the baseline design, achieving up to 65% mercury removal efficiency and about 30% side-benefit, sulfur removal. This project was performed under funding from the US Department of Energy's (DOE's) Small Business Innovation Research (SBIR) Phase І. The results are encouraging for a technology that would provide mercury emissions control as well as a means for sulfur emissions mitigation before coal is burned in coal-fired boilers. At the time of writing this thesis, the team of ACT and Lehigh University were awarded a Phase II project for further development of the spouted bed technology for mercury and sulfur removal from coal.