Ammonium Nitrate Process Steam Integration
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Solution Overview
Problem
The existing integrated process for producing ammonium nitrate and nitric acid requires precise control of ammonia and oxygen levels, and separate streams for each stage, which can be costly and inefficient, especially when using high oxygen-rich oxidizing gases.
Innovation Solution
A process where a gaseous oxidizer feed composed of ammonia, steam, and an oxidizing gas (which can be less than 80% oxygen, such as air) is used to produce nitrogen monoxide and water vapor, which is then cooled and absorbed to form nitric acid, with at least 80% of the steam derived from the ammonium nitrate producing stage and at least 10% of the ammonia from the same stage, allowing for reduced reactor size and mixing precision, and utilizing a heat exchanger to intensify the reaction-absorption process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high oxygen-rich oxidizing gas (more than 80% oxygen) is used in the nitric acid producing stage, then the reaction efficiency and nitrogen monoxide conversion to nitric acid is improved, but the cost of the process increases significantly
Solution Approach 1:
The patent changes the oxygen concentration parameter from high (80%+) to lower levels by using air or oxygen-enriched air as the oxidizing gas, thereby reducing material costs while adjusting other process parameters to compensate
Solution Approach 2:
The patent employs excess air or oxygen-enriched air to compensate for the lower oxygen concentration, ensuring sufficient oxidation capacity is maintained despite using a less concentrated oxidizing gas
2Ease of operation
If separate streams of ammonia are fed to the nitric acid and ammonium nitrate producing stages, then the control of each stage is simplified, but the process complexity and cost increase
Solution Approach 1:
The patent merges the ammonia supply systems by deriving at least 10% of the ammonia for the nitric acid producing stage from the ammonium nitrate producing stage, thereby reducing the number of separate ammonia feed systems and associated complexity
Solution Approach 2:
The ammonia produced in the ammonium nitrate stage serves dual purposes: it is used in the ammonium nitrate reaction and also supplies the nitric acid stage, making the ammonia production system multi-functional
3Productivity
If steam from the ammonium nitrate producing stage is transferred to the nitric acid producing stage, then the process efficiency is improved and external steam requirements are reduced, but the process integration complexity increases
Solution Approach 1:
The patent merges the steam generation and consumption processes by transferring steam from the ammonium nitrate producing stage to the nitric acid producing stage, integrating two previously separate thermal processes
Solution Approach 2:
The ammonium nitrate producing stage generates steam that is then used to meet the steam requirements of the nitric acid producing stage, making the system self-sufficient for steam needs and reducing external utility requirements
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 reduces the size of the ammonium nitrate reactor, minimizes the need for precise mixing, and lowers costs by using a less oxygen-rich oxidizing gas, while maintaining high conversion efficiency of nitrogen monoxide to nitric acid, resulting in a self-sufficient and cost-effective production method with minimal effluent.
Implementation Method 1
the reaction mixture is cooled in a heat exchanger whereby the nitrogen monoxide is oxidised, the water vapour is condensed and the products of the nitrogen monoxide oxidation react with and are absorbed by the condensed water to form a nitric acid stream
Implementation Method 2
the reaction mixture is cooled in a heat exchanger whereby the nitrogen monoxide is oxidised
Implementation Method 3
the products of the nitrogen monoxide oxidation react with and are absorbed by the condensed water to form a nitric acid stream
Implementation Method 4
steam that is generated in the course of concentrating an ammonium nitrate solution in the ammonium nitrate producing stage
Data Source
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AI summary
A process for producing ammonium nitrate is disclosed and in which: a) a gaseous oxidiser feed composed at least substantially of ammonia, steam and an oxidising gas is exposed to conditions whereby the ammonia is oxidised to produce a reaction mixture including nitrogen monoxide and water vapour, b) the reaction mixture is cooled in a heat exchanger whereby the nitrogen monoxide is oxidised, the water vapour is condensed and the products of the nitrogen monoxide oxidation react with and are absorbed by the condensed water to form a nitric acid stream, with substantially all of the nitrogen monoxide in the reaction mixture being converted to nitric acid, and c) the nitric acid stream is reacted with a stream of ammonia in an ammonium nitrate producing stage to form the ammonium nitrate Substantially all of the steam within the oxidiser feed is derived from the ammonium nitrate producing stage, and at least 10% of the ammonia within the oxidiser feed is derived and carried by the steam from the ammonium nitrate producing stage. Also disclosed is ammonium nitrate, in any of its various possible forms, when produced by the disclosed process.