On the reduction of iron catalyst for ammonia synthesis

• Autorzy: Arabczyk W. , Moszyński D. , Jasińska I.
• Języki publikacji: EN

Abstrakty

EN

The influence of the potassium concentration change on the surface area and active surface of an iron catalyst for ammonia synthesis was studied. The removal of potassium leads to the increase of the surface area, while potassium addition gives rise to the decrease of the surface area which is accompanied by the fourfold increase of the active area. The mechanism of the reduction of iron catalyst was proposed. A special attention was paid to the role of promoters. First, the reduction of iron oxides leads to the formation of porous structure with a well-developed surface area. It is due to the formation of aluminium and calcium oxides film on the iron surface. This structure thanks to high oxygen content balances the iron surface tension which results in a high surface area. This process is followed by potassium diffusion from the grain boundaries to the crystallite surface. Potassium atoms are more favoured to form stable structure on the iron surface than aluminium and calcium. It leads to the formation of K+O film on the iron surface. Because K+O structure requires less oxygen atoms part of the iron surface is freed. The balance between chemical bonds and surface energy is disturbed and the surface area is lowered. At the same time some number of free adsorption sites are formed giving rise to the increase of active surface and the activation of a catalyst.

Słowa kluczowe

EN

iron catalyst; ammonia synthesis; reduction; promoters

PL

katalizator żelaza; syntaza amoniaku; redukcja; promotory

• Wydawca: West Pomeranian University of Technology. Publishing House
• Czasopismo: Polish Journal of Chemical Technology
• Rocznik: 2002
• Tom: Vol. 4, nr 4
• Strony: 1--5
• Opis fizyczny: Bibliogr. 29 poz., rys., tab.

Twórcy

autor

Arabczyk W.

• Technical University of Szczecin, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin, Poland

autor

Moszyński D.

• Technical University of Szczecin, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin, Poland

autor

Jasińska I.

• Technical University of Szczecin, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin, Poland

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