Mercury Release and Speciation in Chemical Looping Combustion of Coal

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• 作者：T. Mendiara ; M. T. Izquierdo ; A. Abad ; P. Gay谩n ; F. Garc铆a-Labiano ; L. F. de Diego ; J. Ad谩nez
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：April 17, 2014
• 年：2014
• 卷：28
• 期：4
• 页码：2786-2794
• 全文大小：350K
• 年卷期：v.28,no.4(April 17, 2014)
• ISSN：1520-5029

文摘

In the in situ Gasification Chemical Looping Combustion of coal (iG-CLC), the fuel is gasified in situ in the fuel reactor and gasification products are converted to CO₂ and H₂O by reaction with the oxygen carrier. This work is the first study on mercury release in Chemical Looping Combustion of coal. The determination of mercury speciation (Hg⁰/Hg²⁺) in fuel and air reactors as well as the quantification of the amount of mercury released in each reactor were addressed for the first time. The fraction of the mercury in coal vaporized in the fuel reactor depended mainly on the fuel reactor temperature and the coal type. In the fuel reactor, mercury was mainly emitted as Hg⁰ in the gas phase and the amount increased with the temperature. In the air reactor, mercury was mostly emitted as Hg²⁺. In a real CLC system, mercury emissions to the atmosphere will decrease compared to conventional combustion as only mercury released in the air reactor will reach the atmosphere. However, measures should be taken to reduce Hg⁰ in the CO₂ stream before the purification and compression steps in order to avoid operational problems.