Mercury removal from coal-fired flue gas by the mechanochemical S/FeS modified high sulfur petroleum coke

Abstract

The mechanochemical S/FeS modified high sulfur petroleum coke (HSPC) were prepared in this work. The mercury removal performance of the adsorbents was evaluated in a simulated flue gas fixed bed experimental device. The Brunauer-Emmett-Teller (BET), Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), Hg temperature-programmed desorption (Hg-TPD) and thermogravimetric (TG) were used to obtain the physical and chemical properties of some typical samples. It shows that the mercury removal efficiency (MRE) of mechanochemical S/FeS modified HSPC (MC-S/FeS-PC) increases with increasing the S or FeS addition amount under the same mechanical conditions (600/300 rpm, 60 min), where S is superior to FeS. The mass ratio of carbon to sulfur (RCS) of 4.5 for the MC-S-PC is the optimal sulfur addition amount with the MRE of 98.6%. Mechanochemical S/FeS modification is conducive to the development pore structure of raw HSPC with certain effects. S is the main sulfur form on the surface of MC-S-PC, while thiophene, FeS, and Fe2(SO4)3 are the main sulfur forms of MC-FeS-PC. The mercury compound on used adsorbents is mainly HgS (black). Moreover, another immature mechanism hypothesis about the mercury removal by MC-S-PC is proposed.