Electrolytic Ammonia Synthesis with Membrane Separation
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Solution Overview
Problem
The existing ammonia synthesis processes, such as the Haber-Bosch process, face challenges in efficiently separating ammonia from hydrogen and nitrogen impurities, requiring high energy consumption and expensive separation membranes, and are not well-suited for electrolysis methods which have different reaction conditions.
Innovation Solution
The process combines electrolysis with ammonia separation using membranes or Pressure Swing Adsorption (PSA) to separate nitrogen from ammonia, allowing for efficient recovery of high-concentration ammonia without substantial hydrogen generation, and permits inert component mixing, enabling a more cost-effective and energy-efficient ammonia production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ammonia is separated through liquefaction at high pressure and low temperature, then ammonia can be separated from hydrogen and nitrogen impurities, but enormous energy is consumed and pressure vessels are required
Solution Approach 1:
The patent changes the separation mechanism from physical liquefaction (requiring extreme T and P) to chemical adsorption (operating at moderate conditions). The PSA process uses pressure cycling to control adsorption/desorption of ammonia on the adsorbent material, achieving high-purity separation without the enormous energy consumption of liquefaction
Solution Approach 2:
The patent replaces the mechanical compression and cooling system (pressure vessels, refrigeration equipment) with a chemical adsorption system. The separation is achieved through chemical interaction between ammonia and the adsorbent material, eliminating the need for complex mechanical pressure and temperature control systems
2Productivity
If the Haber-Bosch process is used with iron-based catalysts, then ammonia synthesis is achieved, but high pressure and temperature conditions are required consuming large amounts of energy
Solution Approach 1:
The patent changes the reaction conditions from extreme (400-600°C, 20-40 MPa) to moderate (near ambient T and P). The electrochemical synthesis mechanism allows ammonia production under much milder conditions by using electrical energy to drive the nitrogen reduction reaction, eliminating the need for high thermal and mechanical energy input
Solution Approach 2:
The patent replaces the thermal-mechanical synthesis mechanism (heat and pressure-driven) with an electrochemical mechanism. Electrical energy directly drives the chemical reaction at the electrode surface, substituting the need for high-temperature furnaces and high-pressure reactors with electrochemical cells operating at near-ambient conditions
3Manufacturing precision
If separation membranes are used to separate ammonia from generation gas, then separation efficiency is improved, but expensive membranes are required
Solution Approach 1:
The patent uses adsorbent materials (such as activated carbon, zeolites, or other porous materials) that are inexpensive and can be regenerated through pressure cycling. These materials are much cheaper than specialized separation membranes and can be reused multiple times through the PSA cycle of adsorption and desorption, eliminating the need for expensive membrane materials
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 approach reduces energy consumption and operational costs, facilitates high-purity ammonia recovery, and allows for the use of renewable energy sources, enhancing the process's compatibility with solar or wind power, and enables ammonia's utilization as a liquid fuel for gas turbines.
Implementation Method 1
subjecting a resultant generation gas to treatment using an ammonia separation membrane
Implementation Method 2
subjecting a resultant generation gas to treatment using an ammonia PSA
Implementation Method 3
synthesizing ammonia through electrolysis using water and nitrogen as raw materials
Implementation Method 4
liquefying the high-concentration ammonia recovered through the ammonia separation membrane or the ammonia PSA
Data Source
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AI summary
A high-concentration ammonia production method according to the present invention is characterized by: synthesizing ammonia by conducting electrolysis using water and nitrogen as materials; treating the resulting product gas with an ammonia separation membrane or an ammonia PSA to separate the resulting product gas into high-concentration ammonia and a residual gas; further liquefying the high-concentration ammonia gas recovered by the ammonia separation membrane or the ammonia PSA while recycling the residual gas as a nitrogen gas material for an ammonia synthesis reactor; and re-treating the unliquefied gas separated from the liquefied ammonia with the ammonia separation membrane or the ammonia PSA. According to the present invention, ammonia is synthesized by applying electrolysis, by which substantially no hydrogen is contained in the synthesized ammonia, and the electrolysis is combined with an ammonia separation/recovery treatment with membrane separation and PSA. Thereby, it becomes possible to synthesize and recover high-concentration ammonia with a high efficiency throughout the entire process.