Mercury Emission And High-temperature Mercury Control During Coal Gasification

Emission of trace elements, such as mercury, from coal utilization have already causedgreat damage to our environment as well as human health. Coal gasification is an effectiveclean coal technology, and it can improve the efficiency effectively.The aim of the presentresearch was to investigate the mercury release during coal gasification and explore thehigh-temperature gas adsorbent.In this paper, thermodynamic calculation software HSC was used to reveal themigration and transformation of mercury at high temperature and high pressure during coalgasification. Besides, experimental studies were conducted to study the release of mercury,and the mercury removal capacity of high-temperature adsorbents in a simulated coal gas.HSC thermodynamic calculation results showed that the gas temperature and pressureare the main factors affect the process of mercury during coal gasification. With theincreased of temperature, the release rate of element increased. In different pressure therelease forms are not same. Experimental study showed that temperature residence time andheating rate were the most important impacts on the release of Hg. The higher reactiontemperature were used, the more mercury were released from the coal. At same the longerresidence time was extending, the release rate was increasing. With the increasing heatingrate, the content of Hg2+in the mercury vapor increased.Zinc ferrite and Titanium zinc serise sorbents were good sorbent for Hg at hightemperatures in the simulated gas atmosphere. The Zinc ferrite which droped14.2%Titanium dioxide had better capacity of mecury removel than others,30minutes later, thecapability of adsorption maintains90%. For Titanium zinc series adsorbent, the increasingamount of Al₂O₃-doped in,the more mercury were removing. The Titanium zinc whichdroped25%Al₂O₃had better capacity of mecury removel than other droped rates.At thesame time,it have a stable removal rate,as the reaction time increasing mercury removalefficiency have small changes in30minutes.