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使用原位穆斯堡尔谱和微型反应器考察了铁/活性炭催化剂在不同物相时的F-T反应性以及在实际反应中的物相及其变化,并讨论了铁/活性炭系催化剂不同于传统F-T铁催化剂的特性。发现金属态铁比还原到Fe_3O_4时具有高得多的活性和对烯烃和高碳烃的选择性。在实际反应中,金属铁可转化为碳化铁(ε’-Fe_(2·2)C、ε-Fe_2C和x-Fe_5C_2)并受担载铁粒径的制约,但这些碳化铁与F-T反应性间似没有确定的相依关系。影响F-T反应性的主要是铁在载体上的分散度以及铁质,即活性炭与载体的相互作用。铁与活性炭间合适的相互作用既使铁有较高的还原度,又可能调变铁的电子性不仅是载体,还可能起着电子给予体的作用,促进碳链的增长。而活性炭丰富的微孔又限制了过长链烃的生成。这些特点使得铁/活性炭催化剂具备活性高、气态烯烃和高碳烃(C_5~+)选择性高以及烃分布相对集中的优点。
The in-situ Mossbauer spectroscopy and microreactor were used to investigate the FT reactivity of iron / activated carbon catalysts in different phases and their phases in practical reaction and their changes. The effects of iron / activated carbon catalyst FT iron catalyst characteristics. It was found that the metallic iron has a much higher activity and selectivity to olefins and higher hydrocarbons than to Fe_3O_4. In the actual reaction, metallic iron can be transformed into iron carbide (ε’-Fe 2 (2 2) C, ε-Fe 2 C and x-Fe 5 C 2) and controlled by the supported iron particle size. However, these iron- There does not seem to be a definite dependency. Affect the F-T reactivity is mainly iron in the carrier dispersion and iron, that activated carbon and the carrier interaction. Appropriate interaction between iron and activated carbon Even if the iron has a high degree of reduction, it is possible that the electronic properties of the iron may be modified not only as a support but also as an electron donor to promote the growth of the carbon chain. Activated carbon-rich micropores limit the generation of long chain hydrocarbons. These characteristics make the iron / activated carbon catalyst have the advantages of high activity, high selectivity for gaseous olefins and high-carbon hydrocarbons (C 5 ~ +) and relatively concentrated hydrocarbon distribution.