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在所设计的多功能催化反应及表征装置上,利用一种新的以色谱仪为基础测定催化剂结炭量及结炭C/H 比的方法,并配合氨吸咐TPD,电镜和比表面测量等表征手段,对HZSM-5在甲醇转化过程中的积炭行为进行了研究。在实验条件下,反应温度为350℃和500℃时,HZSM-5上的积炭随反应时间的变化可分别用C_c=1.00×10~(-4)t~(5.00) (350℃)C_c=0.25t~(1.67) (500℃)表示。结炭的产生导致HZSM-5沸石的比活性降低,酸性下降,孔道及孔口堵塞。TPO 及电镜结果表明,HZSM-5上结炭至少有三种形式:初具石墨化的玻璃态炭,无定形炭和部分较富氢的炭(或焦)。在失活的HZSM-5上甲苯歧化反应产物中的对二甲苯选择性随结炭量的增多而提高。
In the designed multi-functional catalytic reaction and characterization device, a new method based on chromatograph was used to determine the amount of carbon in the catalyst and the C / H ratio of the carbonized charcoal. In combination with ammonia adsorption, TPD, electron microscope and specific surface measurement And other characterization methods, the carbon deposition behavior of HZSM-5 in methanol conversion was studied. Under the experimental conditions, when the reaction temperature is 350 ℃ and 500 ℃, the carbon deposition on HZSM-5 with C_c = 1.00 × 10 ~ (-4) t ~ (5.00) (350 ℃) C_c = 0.25t ~ (1.67) (500 ℃). The formation of carbon led to HZSM-5 zeolite specific activity decreased, decreased acidity, pore and orifice blocked. The results of TPO and electron microscopy showed that there are at least three forms of carbon on HZSM-5: initially graphitized vitreous carbon, amorphous carbon and partially hydrogen-rich charcoal (or char). The paraxylene selectivity in the toluene disproportionation reaction product on deactivated HZSM-5 increases with increasing amount of carbon formation.