Experimental study on the structure and reactivity of char in pressurized O2/H2O atmosphere
Chenxi Bai, Yu Zhang, Wenda Zhang, Kun Chen, Lihua Deng, Yijun Zhao, Shaozeng Sun, Dongdong Feng, Jiangquan Wu
Abstract
Pressurized O 2 /H 2 O combustion is regarded as a promising high-efficiency CCS technology. In this study, char combustion in a pressurized O 2 /H 2 O atmosphere was performed with a pressurized horizontal tube furnace. The effects of pressure (0.1–1.3 MPa) and H 2 O concentration (0–60%) on char conversion, char physicochemical structure and reactivity were investigated by means of XPS, Raman, temperature-programed desorption and TGA tests. The results show that both pressurization and H 2 O can promote char conversion and facilitate the formation of carbon‑oxygen bonds on the char surface . Pressure mainly affects the consumption and generation of micropores , while the effect of H 2 O on the pore structure has no obvious selectivity. Pressurization reduces the relative content of C C, while H 2 O has the opposite effect. At low pressure (0.1–0.7 MPa) and low H 2 O concentration (0–40%), pressurization and H 2 O can promote the formation of C(O) on the surface of char. The reactivity of char first decreased and then increased with increasing pressure and increasing H 2 O concentration.