费托合成产物分布的实验研究

Experimental analysis of Fischer-Tropsch synthesis product distribution

将费托合成传统的多级冷却产物收集改进为一级冷却收集,气相产物（C1-C30烃和醇等）经高温管路直接在线分析,液相蜡（C10-C70烃类）离线分析,气相和液相产物均通过内标法精确计量。检验了气相组分高温在线分析方案的准确性和稳定性,通过该精简高效的实验装置获取了工业铁基催化剂更真实的烷烃、烯烃和有机含氧化合物的产物分布,并给出一种适用于本工业铁基催化剂的烃分布关联模型。另外,通过Aspen plus建模估算了液相产物放样闪蒸损失以及分离器中滞留水量随操作工况的变化情况。结果表明,实验操作中的放样闪蒸损失量可以忽略不计;液相滞留水会对产物分布C10-C20区域造成鼓包影响,气液分离器应在高温低压下操作以避免水在液相蜡里的滞留。

The traditional multiple-step collection of Fischer-Tropseh products was replaced by an one-step cooling method. The products （C1-C30 hydrocarbons and alcohols） in the gas phase were analyzed by the on-line GCs with high-temperature heating, while the liquids （C10-C70 hydrocarbons） were analyzed by the off-line GCs. The gases and the liquids were accurately measured by using internal standards, respectively. The work checked the accuracy and the stability of the high-temperature on-line analysis of the gas components. Some more reliable experimental results, e.g. the paraffins, olefins and alcohols formations catalyzed by an industrial iron-based catalyst, were given by this high-efficiency equipment. A correlation between the carbon number and the detailed products was developed. Furthermore, the work estimated the flash loss in product collecting and also the water condensation in the separator with the varied operating conditions by Aspen Plus modeling. It showed that the flash loss is negligible, and the water condensed in the separator, which will be mixed with the liquid wax, could enlarge the yields of the components in C10-C20 region. The separator running at higher temperature and lower pressure would be necessary to avoid the water condensation in the liquid wax.