Iron Catalyst For Ammonia Synthesis Research Articles

Calorimetric determination of the heat of adsorption of nitrogen on a technical iron catalyst for ammonia synthesis at 400°C

The heat of adsorption of nitrogen on a technical iron catalyst at 400°C has been found to be 209 kJ/mol at small coverages. The measurements have been carried out in a Calvet high temperature microcalorimeter.

CATALYSIS BY METALS: THE R H. EMMETT AWARD ADDRESS

Abstract It is a pleasure to receive the second Paul H. Emmett Award in Fundamental Catalysis and to have the opportunity to present this address. The subject, catalysis by metals, is one in which Professor Emmett himself has contributed extensively. His long-standing interest in the iron catalysts for ammonia synthesis, and also his later interest in metal alloy catalysts, are well known.

The role of dislocations in an iron catalyst for ammonia synthesis

The role of dislocations in an iron catalyst for ammonia synthesis

Studies of a triply promoted ammonia synthesis catalyst with an electron probe microanalyzer

Electron probe studies of an iron ammonia synthesis catalyst promoted with Al 2O 3, CaO and K 2O are described. The catalyst was not homogeneous on a micrometer scale. A large portion of the structural and chemical promoters was sequestered by silica to form slag-like envelopes surrounding grains of magnetite which contained only small amounts of these promoters. Large cracks and holes associated with the envelopes provided a good ventilation system in the catalyst particles which facilitated the entry of hydrogen and removal of steam during reduction and the entry of hydrogen sulfide in the poisoning experiments. The reduction started at the periphery of a particle and proceeded from this point toward the center along the envelopes. However, some portions near the periphery remained unreduced while other portions in the interior were already reduced completely. At 25 °C a small amount of hydrogen sulfide was adsorbed in the reduced magnetite grains throughout a particle. At 450 °C large amounts of hydrogen sulfide were adsorbed near the periphery or at positions inside the particle where easy entry of H 2S was possible. In the portions near the periphery where adequate H 2S was available, FeS was formed.

Kinetics of reduction of iron catalysts for ammonia synthesis

The reduction of industrial iron synthetic ammonia catalysts by a stoichiometric mixture of hydrogen and nitrogen has been investigated. The reduction was studied in the temperature range 450–550 °C and for several grain sizes using a spring microbalance in a flow system. It was found that the results satisfy the Seth and Ross kinetic equation for a mixed-control mechanism in which neither the surface reaction nor the diffusion determines the reaction rate. The parameters of the Seth and Ross equation were calculated by a least squares method.

Electron probe studies of an iron ammonia synthesis catalyst

Electron probe studies of an iron ammonia synthesis catalyst promoted with MgO and K 2O are described. The catalyst was not homogeneous on a scale of microns. Two structures were found. The predominant structure, designated as A, was composed of large grains of magnetite containing MgO in about the concentration in the over-all catalyst, and inclusions of potassium silicate. The A-component reduced progressively inward from the periphery of the particle. The minor component, type B, contained a banded structure of light and dark stripes and in some cases inclusions containing large concentrations of MgO. The light and dark bands contained about 2 and 10 wt % Mg, respectively. The type-B material was generally more completely reduced than the A-structure. Potassium and silicon were not found in amounts exceeding the limits of detectability of the probe, about 0.1 wt %, in the iron-rich parts of either the A- or B-components. Thus, the structural promoter MgO was dispersed throughout the iron-rich parts, but most of the chemical promoter K 2O was found in the inclusions. If potassium is present at all in the iron-rich parts, its concentration is less than 0.1 wt %.

Influence of ionizing radiation on the catalytic activity of iron catalysts for ammonia synthesis

Influence of ionizing radiation on the catalytic activity of iron catalysts for ammonia synthesis

Modification of the iron catalyst for ammonia synthesis by certain metals

Modification of the iron catalyst for ammonia synthesis by certain metals

Distribution of promoters in iron catalysts for ammonia synthesis

Distribution of promoters in iron catalysts for ammonia synthesis

A detailed study of iron catalysts for ammonia synthesis: The texture and structure of doubly-promoted coprecipitated catalysts

A detailed study of iron catalysts for ammonia synthesis: The texture and structure of doubly-promoted coprecipitated catalysts

(64)アンモニア合成用鉄触媒中の微量の銅の分光化学的定量

(64)アンモニア合成用鉄触媒中の微量の銅の分光化学的定量