Ca（OH）2对渭化次烟煤及其热解半焦气化性能的影响

Effects of Ca（OH）2 on Steam Gasification of Weihua Sub-Bituminous Coal and Char

以渭化次烟煤为研究对象,在加压固定床中研究了水蒸气气氛下Ca(OH) 2对次烟煤及其热解半焦气化性能的影响。结果表明,Ca(OH) 2能够显著提高次烟煤及其热解半焦的气化性能,且对低温热解半焦的催化性能更好。红外光谱分析表明,钙是通过较强的静电作用、氢键作用均匀分散到次烟煤及热解半焦表面的。随着反应温度升高和Ca(OH) 2添加量增加,热解半焦的碳转化率显著提高,但Ca(OH) 2添加量存在一个饱和值。压力升高对热解半焦的气化性能影响不大,但可显著提高Ca(OH) 2的催化气化性能。将钙基碳酸化反应与气化反应耦合,可以提高热解半焦的转化率及H 2产量。增加Ca(OH) 2的循环反应次数,热解半焦的碳转化率略有降低。

Effects of Ca(OH) 2 on the steam gasification of Weihua sub-bituminous coal and pyrolysis char were investigated with using a pressurized fixed-bed reactor. Experimental results show that Ca(OH) 2, as a catalyst raw material, can significantly enhance the gasification reactivity of coal and char. It is also found that char obtained by pyrolyzing at low temperatures had higher catalytic activity than that obtained at high temperatures. FT-IR characterization results indicate that the dispersion mechanism of Ca(OH) 2 into the surface of coal and char is through electrostatic and hydrogen-bond interactions, which are key factors to improve coal char gasification reactivity. It has been observed that gasification rate increases with temperature and Ca(OH) 2 loading amount. However, there is a saturation point for Ca(OH) 2 loading amount. Carbonation reaction of Ca(OH) 2 can be enhanced by raising reaction pressure, and both carbon conversion and H 2 production will also increase at a higher pressure. Coupling carbonation with gasification reaction can enhance gasification reactivity of char and also increase the H 2 production. Catalytic activity of Ca(OH) 2 decreases slightly when either amounts of calcination or carbonation cycle numbers increase.