ZSM-5(38)/Al-MCM-41复合分子筛对纤维素催化热解的影响

Influence of ZSM-5(38)/Al-MCM-41 composite molecular sieve catalysts on pyrolysis of cellulose

摘要:

以纤维素为原料，以自制的不同硅铝比ZSM-5(38)/Al-MCM-41微-介孔复合分子筛为催化剂，在固定床反应器上进行了催化热解实验。采用XRD表征分子筛，采用GC-MS分析生物油成分，考查了催化剂的改变对生物质热解产物及生物油成分的影响。实验结果表明：添加催化剂后，生物油产率降低，且其含水率也有所增加。与未添加催化剂相比，生物油中D L-2,3-丁二醇有明显提高。其中，ZSM-5(38)/Al-MCM-41(20) 最有利于苯酚、愈创木酚 (2-甲氧基-苯酚) 的生成。此外，这几种催化剂均有利于小分子化合物的生成，其中，ZSM-5(38) 有利于C4~C5化合物的生成，微-介孔复合分子筛则有利于C6~C8化合物的生成。

Abstract:

Pyrolysis of cellulose with different catalysts has been conducted in a fixed-bed reactor. Micro-mesoporous composite molecular sieves of ZSM-5(38)/Al-MCM-41 with different Si/Al ratios were prepared under hydrothermal conditions. With powder X-ray diffraction (XRD), the catalyst samples were characterized. GC-MS was used to analyze the bio-oil composition. The effects of catalysts on the pyrolysis product yields were investigated and the results were compared with the results of experiments performed without catalyst under the same pyrolitic conditions. The presence of the catalysts decreased the liquid yield, while increased the moisture content. The major improvement in the quality of bio-oil with the use of catalysts was the increase of DL-2,3-Butanediol. ZSM-5(38)/Al-MCM-41(20) favored the formation of phenol and 2-methoxy-phenol. In addition, these catalysts were all benefit for the generation of small molecular compounds. Also, it was found that ZSM-5(38) was better for the production of C4?C5 compounds. And micro-mesoporous composite molecular sieves mainly promoted the production of C6?C8 compounds.