Iron Catalyst Promoter Composition for Ammonia Synthesis
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Solution Overview
Problem
Existing iron-containing catalysts for ammonia synthesis lack improved catalytic properties such as activity and long-term stability, particularly in the presence of catalyst poisons like O2 or H2O.
Innovation Solution
An iron-containing catalyst with specific promoter compositions of potassium (0.08-0.6% K2O), calcium (0.8-2.2% CaO), and aluminum (1.0-2.3% Al2O3) is developed, primarily comprising magnetite or wuestite, with a process involving mixing elemental iron and promoter compounds, melting, cooling, and granulating to enhance stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional iron-containing catalysts are used for ammonia synthesis, then the basic catalytic function is provided, but the catalytic activity and long-term stability are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters of the catalyst - specifically setting potassium (K2O) at 0.08-0.6%, calcium (CaO) at 0.8-2.2%, and aluminum (Al2O3) at 1.0-2.3% by weight. These optimized parameter ranges resolve the contradiction by enhancing both stability and activity through specific compositional adjustments
Solution Approach 2:
The patent employs composite materials by combining iron-based catalyst (magnetite or wuestite) with multiple promoter elements (potassium, calcium, and aluminum) in specific proportions. This composite approach creates a synergistic effect where each element contributes to different aspects of catalyst performance, simultaneously improving stability and productivity
2Reliability
If catalysts are exposed to elevated H2O concentrations, then real-world conditions are simulated, but catalyst deactivation occurs
Solution Approach 1:
The patent converts the harmful effect of water (a catalyst poison) into a beneficial test condition. By deliberately exposing the catalyst to elevated H2O concentrations (100-5000 ppmv) during evaluation, the invention identifies catalysts that maintain stability under these challenging conditions, effectively using the harmful factor to screen for superior materials
Solution Approach 2:
The patent applies beforehand cushioning by pre-forming the catalyst with specific promoter compositions (K, Ca, Al) that provide protective effects against water and other catalyst poisons before they cause damage. The optimized compositional parameters create an intrinsic resistance mechanism that cushions the catalyst against deactivation during operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catalyst exhibits improved stability and activity, maintaining performance even under elevated H2O concentrations, leading to higher ammonia yields and extended catalyst lifespan compared to prior art catalysts.
Implementation Method 1
The synthesis of ammonia from the elements hydrogen and nitrogen represents an important large industrial scale application... The catalysts used for ammonia synthesis are predominantly based on iron-containing catalysts
Implementation Method 2
Industrial scale production of the catalyst is carried out by melting the substances present in the catalyst as a mixture in an electric arc furnace or resistance furnace
Data Source
AI summary
An iron-containing catalyst for ammonia synthesis, characterized in that it contains the promoters potassium, calcium and aluminum, wherein the proportion of potassium, calculated as K2O, is 0.08% to 0.6% by weight, the proportion of calcium, calculated as CaO, is 0.8% to 2.2% by weight and the proportion of aluminum, calculated as Al2O3, is 1.0% to 2.3% by weight, is described. The invention further relates to the production of the catalyst according to the invention and to a process for ammonia synthesis using the catalyst according to the invention.