Mechanism study of adsorption of alkali with bed material

Alkali in high-sodium coal causes a variety of problems including fouling,the corrosion of heating surface. It is feasible to capture alkali vapors with bed material,which is used as adsorbent. The fundamentals of the adsorption of alkali with bed material were studied through experiments. The mixture of NaCl and bed material was heated in ther-mogravimetric analysis (TGA) and muffle furnace. X-ray diffraction ( XRD) and X-ray Fluorescence ( XRF) were conducted for the burned materials. The XRF test results show that the Na content is much higher than the Cl content in the burned sample at 800-900 ℃ and at the same blending ratio,the Cl content decreases as the temperature rises. At the same temperature,there is almost no Cl element in the burned sample while the Na content increases with the increase of the blending ratio. The XRD test results show that Na mainly exists in the form of unsolvable sodium in the burned materials such as sodium silicoaluminate. The test results demonstrate that the adsorption process is mainly chemical adsorption.