NO/N2 Gas Mixture Purification via Segmented Catalytic Conversion
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Solution Overview
Problem
Conventional processes for manufacturing NO/N2 gas mixtures often result in impurities, particularly NO2, which are toxic and do not meet medical specifications, leading to unreliable and impure final products.
Innovation Solution
A process involving the purification of nitrogen gas using a nickel catalyst to convert O2 impurities and a molecular sieve to remove H2O impurities, followed by mixing with NO to achieve a NO/N2 mixture with low O2 and H2O concentrations, ensuring high purity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mixing processes are used to produce NO/N2 gas mixtures, then the manufacturing process is simple, but the final product contains toxic NO2 impurities that do not meet medical specifications
Solution Approach 1:
The purification process is divided into three distinct sequential stages: catalytic conversion of O2 to H2O, adsorption of H2O by molecular sieve, and filtration of solid particles. Each stage targets specific impurities independently, ensuring thorough purification while maintaining process manageability and reliability.
Solution Approach 2:
The purification steps are performed before mixing the nitrogen with nitric oxide. By pre-purifying the nitrogen stream to remove O2 and H2O impurities beforehand, the process prevents formation of NO2 during subsequent mixing, ensuring high purity final product without requiring complex post-processing.
2Reliability
If impure nitrogen is used directly in mixing, then the manufacturing process is fast and simple, but toxic NO2 impurities are formed in the final mixture
Solution Approach 1:
The patent performs catalytic conversion and molecular sieve adsorption of impurities before the mixing step. This preliminary purification ensures that when nitrogen mixes with nitric oxide, no O2 or H2O are present to form toxic NO2, guaranteeing product safety while maintaining efficient production throughput.
Solution Approach 2:
The process converts harmful O2 impurities into H2O through catalytic conversion, and then the molecular sieve converts the H2O into adsorbed water molecules on its surface. By transforming harmful impurities into removable forms, the process ensures NO2-free product while maintaining manufacturing efficiency.
3Reliability
If single-stage purification is used, then the process is simple, but it cannot remove both O2 and H2O impurities effectively
Solution Approach 1:
The purification system is segmented into three specialized units: catalytic converter for O2 removal, molecular sieve for H2O removal, and filter for particle removal. Each unit is optimized for its specific function, achieving comprehensive impurity removal while keeping individual components relatively simple and manageable.
Solution Approach 2:
The molecular sieve performs multiple functions: it adsorbs H2O impurities, prevents re-oxidation of NO, and can be regenerated in place. This multi-functionality reduces the need for additional separate systems, balancing purification effectiveness with device complexity.
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 process effectively reduces O2 and H2O impurities to near zero, preventing the formation of toxic NO2, resulting in a reliable and pure NO/N2 gas mixture suitable for medical use.
Implementation Method 1
contacting the impure nitrogen with a catalyst to eliminate or convert at least part of the O2 type impurities
Implementation Method 2
contacting the nitrogen purified in sub-step i) with a molecular sieve to eliminate at least part of the H2O type impurities from step i)
Data Source
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AI summary
The invention relates to a method for manufacturing a NO/N2 gas mixture comprising the steps of purifying impure nitrogen gas containing at least O2-type impurities by contacting the impure nitrogen with a catalyst and then with a molecular sieve; mixing the resulting pure nitrogen with nitric oxide (NO); and obtaining a mixture of NO and pure nitrogen containing an NO content of less than 20% by volume and an O2-type impurity content of less than 5 ppmv and an H2O-type impurity content of less than 40 ppmv. The NO/nitrogen mixture thus formed can be further diluted with pure nitrogen. Such NO/nitrogen mixtures can be used to treat pulmonary vasoconstriction by inhalation in adults or children, particularly in newborns with primary pulmonary hypertension or in patients undergoing cardiac surgery.