Hcl REMOVAL FROM SYNG AS USING SOLID SORBENTS PREPARED BY SPRAY-DRYING METHOD

摘要

IGCC integrated with CCS has been regarded as a promising option to reduce CO_2 emissionunder the situation that coal is the dominant source among fossil fuels for the electricitygeneratingunits. Recently, KEPCO Research Institute proposed the new concept for the precombustionCO_2 capture process, which is named as one loop sorption enhanced water gas shift(SEWGS) process consisted of two fluidized bed reactors. Prior to CO_2 capture process, syngasclean-up should be done since contaminant gases such as H_2S and HCl can cause seriousproblems due to hot corrosion. Warm syngas clean-up has an advantage of increasing the thermalefficiency of IGCC system compared with wet scrubbing operated at low temperature. Warmsyngas clean-up using solid sorbents is the most direct and cost-effective method of providinghigh quality of syngas. In this study, we demonstrated the performance of solid sorbents toremove HCl from coal-derived synthesis gas at temperature range of 300–500°C. The sorbentswhich consist of an active material, a support, inorganic binders, water as solvent, organicadditives as dispersant, a defoamer, and an organic binder were produced by using a spray-dryingtechnique that is easily scalable to commercial quantities. These sorbents were designed for CO_2capture in the fluidized-bed process. However, since the active materials of CO_2 sorbentbasically are similar to those of HCl sorbent, all sorbents can be applied to the HCl treatment. We,therefore, aimed to utilize the sorbent used in CO_2 sorption process, which enables to decreaseprocess cost. The removal performance of various CO_2 sorbents was evaluated in terms ofsorption capacity and kinetics as a function of reaction temperature. HCl sorption capacities ofNa-, K-, and Na/K-based sorbents were determined on the basis of absorbed Cl- ion ranging from15 to 30 wt% in the experiment with the simulated syngas (HCl 2500ppm, H_2 20%, N_2 3%, andCO balance).