循环流化床还原性气氛对固硫效果的影响

利用热天平对固硫所用石灰石的煅烧特性进行了试验研究,并选取不同煤质的煤样在旋转炉中进行了模拟CFB运行状态的固硫试验,分析了钙硫摩尔比、床温和固硫时间对固硫效果的影响.结果表明：床温在850℃左右、钙硫比为2.3时能得到一个较高的固硫效率;升温速度越大,石灰石开始分解的时间越早,则其分解速度越快.固硫过程中存在一个最佳的反应时间：反应时间过短,固硫反应不完全;反应时间过长,由于燃煤后期还原性气氛的形成容易发生硫酸盐分解,导致固硫效率降低.在适当的钙硫摩尔比工况下,存在一个最佳的炉膛温度和气氛的匹配,使固硫效果达到最佳.

Effect of Reduction Atmosphere on Sulfur Dioxide Capture in CFB

Experimental studies were carried out in a thermo-balance reactor on the calcination characteristics of limestone for sulfur dioxide capture,while sulfur capture tests performed in a simulated rotary furnace with coal samples of different grades,so as to analyze the effect of Ca/S molar ratio,bed temperature and reaction time on the capture process.Results show that high desulfurization efficiencies can be obtained at a bed temperature of 850 ℃ and a Ca/S molar ratio of 2.3.The higher the temperature rising speed,the earlier the limestone starts to decompose,resulting in a higher decomposition speed of limestone.During desulfurization process,there exists an optimal reaction time,compared with which if actual reaction time is shorter than it,incomplete reaction will be resulted;whereas if actual reaction time is longer than it,lower desulfurization efficiency will be produced,due to partial decomposition of sulfate caused by reduction atmosphere in late stage of coal combustion.At an appropriate Ca/S molar ratio,there exists an optimal matching condition of furnace temperature with reaction atmosphere,which produces the highest desulfurization efficiency.