Ammonia Synthesis Gas Circulation at Lower Reaction Pressure
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Solution Overview
Problem
Existing ammonia synthesis systems require high energy for both cooling and increasing reaction pressure, leading to increased overall energy consumption despite reduced cooling costs.
Innovation Solution
An ammonia synthesis system operating at a reaction pressure of 10 MPa or less, using a catalyst with a prescribed ammonia gas concentration, and incorporating a gas-liquid separator and ammonia cooler to optimize ammonia extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reaction pressure is increased to enhance ammonia extraction efficiency, then the ammonia extraction efficiency is improved, but the energy consumption for compression increases
Solution Approach 1:
The patent changes the reaction pressure parameter to 10 MPa or less (lower than conventional pressures) while compensating through optimized catalyst selection and gas circulation management. This parameter change reduces compression energy consumption while maintaining acceptable ammonia extraction efficiency through alternative process optimizations.
Solution Approach 2:
The patent employs a gas circulation system that recycles unreacted gases back to the reaction zone, effectively copying the function of high-pressure compression through continuous gas recycling. This allows the system to maintain high ammonia concentration in the circulated gas without requiring excessive compression pressure.
2Productivity
If the cooling temperature is reduced to extract ammonia as liquid, then the ammonia extraction efficiency is improved, but the cooling energy consumption increases
Solution Approach 1:
The patent uses the cold gas from the cooling section to pre-cool the incoming hot gas from the reaction zone, allowing the system to serve its own cooling needs. The cold gas from ammonia condensation is utilized to cool the reaction effluent, reducing external cooling energy requirements while maintaining effective ammonia extraction.
Solution Approach 2:
The patent exploits the phase transition of ammonia from gas to liquid during cooling, utilizing the latent heat release during condensation to assist in the cooling process. The phase change itself provides a thermal sink that reduces the external cooling energy required, while the liquid ammonia is then separated from the gas stream.
3Productivity
If a high-performance catalyst is used to increase ammonia concentration, then the ammonia synthesis efficiency is improved, but the catalyst cost increases
Solution Approach 1:
The patent implements a dynamic gas circulation system that adjusts the composition and flow rate of gases to the catalyst based on real-time process conditions. By dynamically optimizing the gas mixture (maintaining ammonia concentration at 3% or more) and flow rates, the system maximizes catalyst effectiveness without requiring expensive catalyst materials, achieving high synthesis efficiency through process control rather than catalyst cost.
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
Reduces the total energy required for ammonia production while maintaining efficiency in ammonia synthesis.
Implementation Method 1
ammonia synthesis catalyst under a condition of a reaction pressure of 10 MPa or less
Implementation Method 2
an ammonia cooler that cools an ammonia-containing gas which is discharged from the ammonia synthesis reaction unit
Implementation Method 3
a gas-liquid separator that separates liquefied ammonia produced from the ammonia-containing gas cooled by the ammonia cooler from a circulated gas
Data Source
AI summary
An ammonia synthesis system includes an ammonia synthesis reaction unit that synthesizes ammonia from nitrogen and hydrogen; an ammonia cooler that cools an ammonia-containing gas discharged from the ammonia synthesis reaction unit; a gas-liquid separator that separates ammonia liquefied by the ammonia cooler from a circulated gas; and an ammonia synthesizing gas supplying unit that supplies nitrogen gas and hydrogen gas. The circulated gas supplied to the ammonia synthesis unit has an ammonia gas concentration of 3% by volume or more. A method for producing ammonia includes reacting nitrogen and hydrogen using a circulated gas having an ammonia gas concentration of 6% by volume or more and using an ammonia synthesis catalyst under a condition of a reaction pressure of 10 MPa or less to produce ammonia. The ammonia synthesis system and ammonia production method have a reduced energy requirement.