In-Situ Study of Volatile Potassium Produced on Carbon Matrix and its Contribution to Other Char Particle Gasification

Abstract

To understand the volatilization behavior between potassium and carbon matrix, the experiments were carried out in high temperature stage microscope (HTSM) and fixed-bed reactor. The migration of volatile potassium between particles was analyzed by SEM-EDS, while the chemical fraction of potassium species was determined by AAS, and XPS was used to investigated the elements on the surface of the samples. The results showed that potassium would volatile at 765-770°C, C/K≈6.2-9.5(wt%), which would be adsorbed by the other char particles, leading to an increasing of the content of soluble potassium and ion-exchanged potassium, promoting carbon conversion in a limited effect, resulting in a decreasing of hydroxyl functional groups on the char particles. Meanwhile, the potassium content was proportional to the migration distance, the migration distance was about 720-800 μm at maximum under HTSM.

Keywords: In-situ study, Volatile potassium, Catalytic char gasification