Selective Nitrogen Monoxide Separation in Hydroxylamine Exhaust
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Solution Overview
Problem
Existing processes for recycling nitrogen monoxide and hydrogen from exhaust gases in hydroxylamine production are inefficient due to the formation of explosive mixtures and reduced space-time yield, leading to high investment costs and nitrogen oxide loss.
Innovation Solution
A process involving selective separation of nitrogen monoxide in a first stage, followed by its recycling and subsequent separation of nitrous oxide in a second stage using physical or chemical processes, allowing for complete utilization of nitrogen monoxide and reduction of nitrous oxide to prevent explosive mixtures and maximize yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If exhaust gas is recycled directly into the synthesis, then hydrogen and nitrogen monoxide are utilized, but nitrous oxide levels increase forming explosive mixtures
Solution Approach 1:
The exhaust gas treatment is divided into multiple separation stages. The first separation stage removes nitrogen monoxide, the second stage removes nitrous oxide, and the third stage removes nitrogen. This segmented approach allows selective removal of harmful components while preserving valuable ones for recycling.
Solution Approach 2:
Nitrous oxide and nitrogen are extracted and removed from the exhaust gas stream before recycling. This extraction prevents the formation of explosive mixtures and maintains safe operating conditions while allowing hydrogen and nitrogen monoxide to be recycled.
2Use of energy by stationary object
If exhaust gas is burned to recover energy, then steam generation is achieved, but valuable materials are lost
Solution Approach 1:
Instead of burning the exhaust gas to recover energy, the process converts the harmful nitrous oxide and nitrogen into beneficial separated streams that can be safely removed. The valuable hydrogen and nitrogen monoxide are then recycled back into the synthesis process, turning potential waste into useful resources.
Solution Approach 2:
The process discards harmful components (nitrous oxide and nitrogen) through selective removal while recovering valuable materials (hydrogen and nitrogen monoxide) for recycling. This selective discarding and recovering approach maximizes material utilization while eliminating safety hazards.
3Productivity
If nitrogen levels increase in the process, then recycling is possible, but space-time yield is significantly reduced
Solution Approach 1:
Nitrogen is removed in advance in the third separation stage before the gas is recycled into the synthesis process. This preliminary removal prevents nitrogen accumulation that would otherwise reduce the space-time yield, while still allowing recycling of the beneficial components.
4Manufacturing precision
If pressure swing adsorption on molecular sieves is used, then nitrous oxide separation is achieved, but aggressive nitrogen monoxide attacks absorption material
Solution Approach 1:
The separation process is segmented into distinct stages with different functions. The first separation stage handles nitrogen monoxide removal using methods that are resistant to its aggressiveness, while the second stage handles nitrous oxide separation. This segmentation protects the absorption materials from damage by aggressive nitrogen monoxide.
Solution Approach 2:
The process uses intermediary separation steps and appropriate material selections that mediate between the aggressive nitrogen monoxide and the sensitive absorption materials. By introducing intermediate treatment stages and selecting compatible materials, the direct contact between nitrogen monoxide and vulnerable absorption materials is avoided.
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 process enables nearly complete utilization of nitrogen monoxide and reduction of nitrous oxide, reducing the need for high-cost investments and minimizing nitrogen oxide loss, thereby enhancing the space-time yield and economic efficiency of hydroxylamine production.
Implementation Method 1
nitrogen monoxide is selectively separated from the exhaust gas of the plant for producing hydroxylamine or hydroxylammonium salts in a first separation stage
Implementation Method 2
subsequent separation of nitrous oxide in a second separation stage using physical or chemical processes
Implementation Method 3
catalytic reduction of nitrogen monoxide with hydrogen for the purpose of utilizing at least part of the nitrogen monoxide
Implementation Method 4
producing hydroxylamine or hydroxylammonium salts by catalytically hydrogenating nitrogen monoxide with hydrogen
Data Source
AI summary
The invention proposes a method for processing the waste gas of a system for producing hydroxylamine or hydroxyl ammonium salts by means of catalytic reduction of nitrogen monoxide with hydrogen for the purpose of utilizing at least part of the nitrogen monoxide present in the waste gas, and possibly hydrogen, for the production of hydroxylamine or hydroxyl ammonium salt, characterized in that nitrogen monoxide is selectively separated from the waste gas of a system for producing hydroxylamine or hydroxyl ammonium salts in a first separating step.