Catalyst-Sorbent Structure for Low-Energy Single-Pass Ammonia Synthesis
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Solution Overview
Problem
Existing ammonia synthesis processes face inefficiencies due to low net conversions, high energy requirements, and the need for large reactor volumes, with significant recycle of unreacted nitrogen and hydrogen feedstocks, and thermodynamic equilibrium limitations.
Innovation Solution
A catalyst-sorbent structure integrating an active catalyst with a specialty sorbent within the same particle, allowing for ammonia synthesis and sorption in a single stage, with the catalyst and sorbent in intimate or molecular contact, facilitating high net conversion and efficient ammonia removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate adsorption vessel is used after Haber-Bosch reactor, then ammonia sorption is achieved, but device complexity and energy requirements increase
Solution Approach 1:
The patent combines the catalyst and sorbent into a single integrated particle structure where the catalyst portion synthesizes ammonia and the sorbent portion immediately adsorbs it. This merging eliminates the need for separate reactors and recycle lines, reducing device complexity while maintaining sorption efficiency.
Solution Approach 2:
The integrated catalyst-sorbent particle performs multiple functions simultaneously: nitrogen and hydrogen conversion, ammonia synthesis, and ammonia adsorption within a single structural unit. This multi-functionality reduces the number of separate components needed in the system.
2Productivity
If high pressure and temperature are used for ammonia synthesis, then conversion rate improves, but energy consumption increases
Solution Approach 1:
The patent employs a sorbent material with specific physical and chemical properties (porosity, surface area, adsorption capacity) that enables effective ammonia adsorption at lower temperatures and pressures. This parameter optimization allows the system to achieve high conversion rates without requiring extreme operating conditions.
Solution Approach 2:
The integrated catalyst-sorbent composite structure combines materials with complementary properties: the catalyst facilitates ammonia synthesis while the sorbent with optimized pore structure and surface characteristics enables efficient adsorption at milder conditions, reducing overall energy requirements.
3Productivity
If large reactor volume is used to achieve high net utilization, then feedstock conversion improves, but device complexity and cost increase
Solution Approach 1:
By integrating the adsorption function within the catalyst particle itself, the system achieves high net utilization of feedstock in a compact configuration. The immediate adsorption of synthesized ammonia prevents equilibrium limitations, allowing smaller reactor volumes to achieve the same productivity.
4Productivity
If recycle lines are used for unreacted feedstock, then feedstock utilization improves, but device complexity and energy requirements increase
Solution Approach 1:
The patent extracts the ammonia product from the reaction zone through immediate adsorption by the sorbent portion of the integrated particle. This removal of product at the site of formation eliminates the need for complex recycle lines to manage unreacted feedstock, simplifying the overall system structure.
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 catalyst-sorbent structure achieves high nitrogen and hydrogen conversion to ammonia in a single pass, reducing the need for recycle lines and reactor volume, and operates at lower temperatures and pressures, enhancing efficiency and reducing energy consumption.
Implementation Method 1
a catalyst portion capable of converting an unreacted hydrogen feedstock and an unreacted nitrogen feedstock to an ammonia product
Implementation Method 2
a sorbent portion capable of absorbing the ammonia product produced by the catalyst portion
Data Source
AI summary
An active catalyst for ammonia synthesis is integrated with a specialty sorbent in a composition or composite, such that the catalyst portion and the sorbent portion are in direct intimate contact, which overcomes the thermodynamic limits for conversion. The sorbent may comprise a metal halide absorbent, zeolite adsorbent, other material absorbents or adsorbents, to capture ammonia as it is produced in intimate or near molecular contact with the catalyst, wherein the composition/composite may be provided in the form of a granular or pellet structure. By removing ammonia essentially as it forms, the forward reaction for producing ammonia can continue nearly unabated such that high net conversion can be achieved in a single pass or cumulative within segmented reactors as operated in series.