CaSO_(4)载氧体在煤气化化学链燃烧中的脱汞

Mercury removal by CaSO_(4) oxygen carrier during in-situ gasification and chemical-looping combustion of coal

为了研究载氧体在煤气化化学链燃烧中的脱汞机理,选择CaSO_(4)载氧体作为研究对象,900℃的反应温度下,在还原反应器中通入CO_(2)气体和水蒸气作为气化介质进行实验。结果表明:以CaSO_(4)作为载氧体的煤气化化学链燃烧中,CaSO_(4)载氧体本身促进Hg~0的氧化,但CaSO_(4)分解产生的SO_(2)抑制Hg^(0)的氧化。CaSO_(4)促进煤气化化学链燃烧产生S单质,会进一步与Hg^(0)反应生成多种复杂的HgS_(n),降低了烟气中Hg^(0)含量,提高了脱汞效率。同时CaSO_(4)载氧体在还原-氧化的循环反应中具有良好的循环特性,是一种优良的化学链载氧体。

To understand the mechanism of mercury removal by oxygen carriers during in-situ gasification and chemical-looping combustion of coal,we used CaSO_(4) as oxygen carrier and CO_(2) and water vapor as gasification medium in a reduction reactor working at 900℃.Results showed that the CaSO_(4) oxygen carrier itself promoted the oxidation of Hg~0,but the SO_(2) produced by the decomposition of CaSO_(4) inhibited the oxidation of Hg^(0).CaSO_(4) promoted the chemical-looping combustion of coal to produce element S,which would further react with Hg^(0) to generate a variety of complex HgS_n.This,reduced the Hg^(0) content in the flue gas and improved the mercury removal efficiency.In addition,the CaSO_(4) oxygen carrier has good cycle characteristics in the reduction-oxidation cyclic reactions,indicating an excellent chemical-looping oxygen carrier.