摘要
提出了一种热重-质谱联用测定积炭催化剂焦炭量及焦炭H/C比的方法。该方法通过惰性气氛高温吹扫排除自由水及结合水对测定的影响,利用热重分析仪测定氧化条件下积炭SAPO-34催化剂的燃烧质量损失,得到焦炭含量;利用草酸钙标样标定质谱特征峰校正因子,结合积炭氧化产物的质谱检测结果,计算获得焦炭H/C的物质的量比。对聚丙烯(n(H)/n(C)=2)样品的测定验证了该方法的准确性。对两个不同焦炭含量的SAPO-34催化剂样品的多次检测显示结果重复性良好。测定结果显示,随着反应时间延长,SAPO-34催化剂焦炭含量增加、焦炭H/C比降低、催化剂吸湿能力降低。
A method using thermogravimetry-mass spectrometry （TG-MS） was proposed to measure the coke content and its H/C ratio on the coked catalyst, which used temperature programmed pretreatment in an inert gas to remove the adsorbed water and water of crystallization in the samples to avoid them affecting the measurement results, then used TG to determine the coke content of the coked catalyst by measuring the mass loss of the deactivated catalyst during temperature programmed oxidation, and used the thermal decomposition of a reference sample CaC2O4＆#183;H2O to get the correction factors for the MS signals, by which the H/C molar ratio could be calculated using the peak areas of the MS spectra when the coke was burned under an oxidizing circumstance. The measurement results for the polypropylene （H/C molar ratio =2） sample verified the accuracy of the proposed method, and the results from two coked SAPO-34 catalysts showed good reproducibility in repeated measurements. The results indicated that with the increase of time on stream in the flow reactor, the coke content of the SAPO-34 catalyst increased, while the H/C ratio of the coke and water adsorbed on the coked catalyst decreased.
出处
《天然气化工—C1化学与化工》
CAS
CSCD
北大核心
2014年第3期5-9,35,共6页
Natural Gas Chemical Industry
基金
国家863项目(2012AA051001)
