Activated carbon has been used commercially to remove SO2 from coal combustion flue gas. However, the role of inherent CaO in activated carbon is uncertain. In this study, the adverse effects of inherent CaO in the activated carbon derived from coconut shell (CSAC) on its desulfurization performance were systematically studied at the temperature range of 60-100 °C in a fixed-bed reactor. The solid sorbent samples were analyzed using scanning electron microscopy, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis. The flue gas compositions were analyzed by using an online flue gas analyzer. The experimental results showed that the inherent CaO had a profoundly adverse influence on the desulfurization capacity and efficiency of CSAC at all of the temperatures studied. This adverse influence was clearly identified by a comparison of the desulfurization performance of the raw CSAC to those of the acid-washed CSAC samples. It was found that the removal of the inherent CaO from CSAC using a pretreatment of HCl aqueous solution led to an increase in the desulfurization capacity of 41.7%. The adverse effects were attributed to the conversion of CaO into dihydrate calcium sulfate whiskers which formed solid crystals that blocked the micropores of the CSAC particles.

中文翻译：

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烟道气脱硫过程中椰子壳衍生活性炭中固有CaO对其性能的不利影响。

活性炭已在商业上用于从燃煤烟气中去除SO2。但是，固有的CaO在活性炭中的作用尚不确定。在这项研究中，系统地研究了固定床反应器中温度为60-100°C时，椰壳衍生的活性炭（CSAC）中固有的CaO对其脱硫性能的不利影响。使用扫描电子显微镜，X射线衍射，X射线荧光，傅里叶变换红外光谱和Brunauer-Emmett-Teller分析对固体吸附剂样品进行分析。使用在线烟气分析仪分析烟气成分。实验结果表明，在所有研究温度下，固有的CaO对CSAC的脱硫能力和效率都具有深远的不利影响。通过将原始CSAC的脱硫性能与酸洗过的CSAC样品的脱硫性能进行比较，可以清楚地识别出这种不利影响。发现使用HCl水溶液的预处理从CSAC中除去固有的CaO导致脱硫能力增加41.7％。不利影响归因于CaO转化为二水合硫酸钙晶须，该晶须形成了固体晶体，阻塞了CSAC颗粒的微孔。