钙添加剂对Na_(2)CO_(3)催化高铝煤焦水蒸气气化反应性的影响

Effect of calcium additive on Na_(2)CO_(3)-catalyzed gasification reactivity of a high-aluminium coal char with steam

以孙家壕高铝煤为实验煤样,将煤样在800℃制成煤焦,采用热重分析仪(TGA)研究了钙添加剂对孙家壕煤焦Na_(2)CO_(3)催化水蒸气气化反应性的影响。结果表明:Ca(OH)_(2)对孙家壕煤焦水蒸气气化具有催化作用,在对孙家壕煤焦进行800℃Ca(OH)_(2)催化水蒸气气化时,Ca(OH)_(2)的负载量在15%(质量分数,下同)时达到饱和;通过比较Na_(2)CO_(3)和Ca(OH)_(2)对孙家壕煤焦800℃水蒸气气化的催化活性,发现Na_(2)CO_(3)的催化气化活性比Ca(OH)_(2)的催化气化活性大,负载5%Na_(2)CO_(3)和10%Ca(OH)_(2)的孙家壕焦的800℃水蒸气气化反应性相等;添加10%Ca(OH)_(2)添加剂可以使负载10%Na_(2)CO_(3)的孙家壕煤焦在700℃,750℃,800℃,850℃时的水蒸气气化反应性指数分别提高42.31%,77.60%,137.00%和153.00%,Ca(OH)_(2)对Na_(2)CO_(3)的催化气化活性的提高幅度随着温度升高而增大;尽管Ca(OH)_(2)的催化气化活性不如Na_(2)CO_(3),但添加Ca(OH)_(2)可以显著提高负载Na_(2)CO_(3)孙家壕煤焦的水蒸气气化反应性,Ca(OH)_(2)和Na_(2)CO_(3)催化剂在煤焦气化过程中存在协同作用,Ca(OH)_(2)通过抑制Na_(2)CO_(3)的失活作用,从而促进了Na_(2)CO_(3)对孙家壕煤焦水蒸气气化的催化作用。因此,钙添加剂能够提高负载Na_(2)CO_(3)的高铝煤焦的水蒸气气化反应性,钙添加剂对Na_(2)CO_(3)催化气化活性具有促进作用。

To investigate the effect of calcium additives on Na_(2)CO_(3)-catalyzed gasification of high-aluminium coal char with steam,Sunjiahao(SJH)high-aluminium coal and Ca(OH)_(2)were selected as the experimental coal sample and calcium additive respectively in this study.The SJH char was prepared from the raw coal sample at 800℃.The effect of Ca(OH)_(2)on Na_(2)CO_(3)-catalyzed steam gasification reactivity of SJH coal char was studied with a thermogravimetric analyzer(TGA).The experimental results show that Ca(OH)_(2)has a catalytic effect on the steam gasification of SJH char and the catalytic effect reaches saturation at 15%(mass fracion,the same below)Ca(OH)_(2)loading at 800℃.The comparison between the steam gasification reactivity of SJH char impregnated with Na_(2)CO_(3)and that of SJH char with Ca(OH)_(2)loaded at 800℃shows that the catalytic activity of Na_(2)CO_(3)is higher than that of Ca(OH)_(2).SJH char loaded with 5%Na_(2)CO_(3)and 10%Ca(OH)_(2)has equal steam gasification reactivity at 800℃.The addition of 10%Ca(OH)_(2)could increase the steam gasification reactivity of SJH char loaded with 10%Na_(2)CO_(3)by 42.31%,77.60%,137.00%and 153.00%at 700℃,750℃,800℃and 850℃,respectively,which shows that the promotion of catalytic gasification activity by Ca(OH)_(2)increases with increasing temperature.Although the catalytic activity of Ca(OH)_(2)is inferior to that of Na_(2)CO_(3),the addition of Ca(OH)_(2)can remarkably improve the steam gasification reactivity of SJH char impregnated with Na_(2)CO_(3)owing to the synergistic catalytic effect of Ca(OH)_(2)and Na_(2)CO_(3)catalysts in the SJH char gasification process,where the deactivation of Na_(2)CO_(3)is inhibited by Ca(OH)_(2).Therefore,calcium additive can enhance the steam gasification reactivity of the high-aluminium coal char loaded with Na_(2)CO_(3),and calcium additive can promote the catalytic activity of Na_(2)CO_(3)for the steam gasification of SJH char.