Influence of mineral transformation on the reactivity evolution during rice straw char–NO reaction
Influence of mineral transformation on the reactivity evolution during rice straw char–NO reaction
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DOI：
10.1016/j.fuel.2013.05.102
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发表时间：
2013-11
期刊：
影响因子：
7.4
通讯作者：
Xingyuan Wu;Q. Song;Haibo Zhao;Zhi-hao Zhang;Long-li Zhang;Q. Yao
中科院分区：
文献类型：
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作者：
Xingyuan Wu;Q. Song;Haibo Zhao;Zhi-hao Zhang;Long-li Zhang;Q. Yao
本研究以两种不同的半焦为研究对象，分别是未经处理的稻草半焦和经过酸洗处理的稻草半焦。在900 °C和1000 °C的固定床反应器中研究了它们在半焦-NO反应过程中的反应性演变。采用BET法和电感耦合等离子体原子发射光谱法（ICP-AES）对不同转化率下的煤焦样品进行了分析。在900 °C和1000 °C下，经酸洗的半焦的反应活性均先升高后降低，在转化率约为70%时出现转折点。这与比表面积的发展一致。在900 °C下，原始半焦的反应活性变化与酸洗半焦相似，但在1000 °C下，原始半焦的反应活性不断下降至零，这与原始半焦的比表面积变化相矛盾。焦炭中矿物质含量的测定表明，K，Ca和Mg是原始焦炭中的主要矿物质。在煤焦-NO反应过程中，K、Mg和Ca发生了转化，在1000 °C时，从煤焦转化率Xchar = 0%到Xchar = 44.6%，酸溶性K和Mg的浓度分别降低了26.5%和2.7%，而Ca的浓度增加了20.4%。在煤焦与NO反应过程中，酸溶性钾的变化规律与煤焦的反应性演化规律一致，表明酸溶性钾对煤焦与NO反应过程中煤焦的反应性演化起着重要作用。半焦的比反应活性与半焦中酸溶性钾的浓度呈近似线性关系。
Two kinds of chars were used in this research, the original rice straw char and the acid washed rice straw char. Their reactivity evolution during the char–NO reaction was studied in a fixed bed reactor at 900 °C and 1000 °C. The char samples obtained at different conversion were analyzed by BET and Inductively Coupled Plasma–Atomic Emission Spectrometry (ICP–AES). The reactivity of the acid washed char increased first and then decreased with the turning point at the char conversion of about 70% at both 900 °C and 1000 °C. This was consistent with the development of specific surface area. The reactivity evolution of the original char was similar as acid washed char at 900 °C, but the reactivity decreased continually to zero at 1000 °C, which contradicted the specific surface area development of original char. The measurements of mineral concentrations in char showed that K, Ca and Mg were the primary minerals in the original char. During the char–NO reaction, the transformation of K, Mg and Ca occurred, the concentrations of acid soluble K and Mg decreased 26.5% and 2.7% respectively, while the concentration of Ca increased 20.4% from char conversionXchar= 0% toXchar= 44.6% at 1000 °C. The transformation of acid soluble K was consistent with the reactivity evolution of char during the char–NO reaction, which indicates that acid soluble K played an important role on char reactivity evolution during the char–NO reaction. The specific reactivity of char had a nearly linear relationship with the concentration of acid soluble potassium in char.