Ammonia Purification via Multi-Stage Adsorption
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Solution Overview
Problem
Current methods for purifying ammonia to high purity for electronic applications are inadequate due to sensitivity of advanced catalysts to impurities, energy-intensive distillation processes, and the use of metallic sodium, which is undesirable in semiconductors.
Innovation Solution
A multi-stage process involving columns packed with specific materials like aluminium oxide, CaO, and activated carbon, with temperature-controlled operation, to efficiently remove impurities from ammonia and syngas streams, maintaining a consistent gas flow and using readily available chemicals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metallic sodium is used to purify ammonia, then ammonia purity is improved, but the method becomes unsuitable for electronics applications due to sodium contamination
Solution Approach 1:
The invention extracts and removes harmful sodium impurities from the ammonia purification process by replacing metallic sodium with alternative materials (molecular sieves, activated carbon, calcium sulfate) that do not introduce contamination, while still achieving the required purification of oxygen-containing compounds to below 0.1 ppm
Solution Approach 2:
The invention replaces the expensive and problematic metallic sodium with more economical and safe alternative purification materials such as molecular sieves, activated carbon, and calcium sulfate, which can be easily replaced or regenerated without introducing contamination risks
2Manufacturing precision
If fractional distillation is used to purify ammonia, then ammonia purity is improved, but energy consumption and equipment complexity increase significantly
Solution Approach 1:
The invention replaces the mechanical distillation system with a chemical adsorption system using molecular sieves, activated carbon, and calcium sulfate beds, which achieve equivalent or superior purification without the high energy consumption and complex equipment requirements of fractional distillation
Solution Approach 2:
The invention changes the purification approach from thermal-based (distillation requiring temperature and pressure changes) to chemical-based (adsorption at ambient or near-ambient conditions), significantly reducing energy consumption while maintaining high purification efficiency
3Productivity
If advanced catalysts are used in ammonia synthesis, then synthesis efficiency is improved, but sensitivity to impurities in syngas increases
Solution Approach 1:
The invention applies preliminary purification of syngas before it enters the ammonia synthesis reactor, using molecular sieves and activated carbon to remove water vapor, carbon oxides, and other impurities that would poison advanced catalysts, thereby protecting the high-efficiency catalysts from deactivation
Solution Approach 2:
The invention introduces intermediary purification stages (molecular sieve beds, activated carbon beds, calcium sulfate beds) between the syngas source and the ammonia synthesis reactor, which act as mediators to remove harmful impurities while allowing the desired syngas components to pass through to the catalyst
4Manufacturing precision
If multiple purification stages are applied to remove all impurities, then ammonia purity is improved, but process complexity increases
Solution Approach 1:
The invention merges multiple purification functions into a single integrated system using a combination of molecular sieve beds, activated carbon beds, and calcium sulfate beds arranged in series, which simultaneously remove multiple types of impurities (water, carbon oxides, hydrocarbons, oxygen) in one pass through the purification train
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
This method achieves ammonia and syngas purification to 99.9999% purity with a simple apparatus and available chemicals, overcoming the limitations of existing technologies by effectively removing impurities and maintaining a technologically convenient and energy-efficient process.
Implementation Method 1
ammonia or a mixture of gases under pressure of from 0.1 to 25 MPa is passed through a column packed with aluminium oxide
Implementation Method 2
columns packed with specific materials like aluminium oxide, CaO, and activated carbon
Implementation Method 3
columns packed with specific materials like aluminium oxide, CaO, and activated carbon
Data Source
Figure 1~2
AI summary
Method for purification of ammonia or mixtures of nitrogen and hydrogen, or nitrogen, hydrogen and ammonia, according to which: a) ammonia or a mixture of gases under pressure of from 0.1 to 25 MPa is passed through a column packed with aluminium oxide with a large specific surface area; b) the ammonia or mixture of gases is then passed through a column packed with CaO, NaOH, KOH or an NaOH/KOH melt, separately or in a mixture, at 20 to 70°C and under pressure of from 0.1 to 25 MPa; c) next, the ammonia or mixture of gases is passed through a column packed with activated carbon having a specific area of 100÷3000 m2 /g with sodium, potassium, caesium, magnesium, calcium, strontium, barium or cerium nitrates(V) or nitrates(III) deposited on its surface, separately or in a mixture; the aforementioned steps being realised in a serial process at a gas stream flow rate in the range of 100 dm3/h to 1000 m3/h.