Reverse Flow Reactor Reforming for CO2-Rich Ammonia and Urea Feed
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Solution Overview
Problem
Conventional hydrocarbon reforming processes, such as those used in ammonia production, generate substantial amounts of CO2, contributing significantly to global emissions, and the resulting flue gas is difficult to integrate with ammonia production processes due to its composition and pressure, leading to inefficiencies in CO2 sequestration and hydrogen production.
Innovation Solution
The use of reverse flow reactors with controlled combustion and high-purity oxygen sources, such as from an air separation unit, allows for direct heating of the reaction environment, producing an oxygen-depleted flue gas rich in CO2 and H2O, which can be easily separated and utilized for ammonia synthesis, reducing the need for additional separation steps and increasing the efficiency of CO2 capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional steam methane reforming or autothermal reforming is used to provide hydrogen for ammonia production, then hydrogen production is achieved, but substantial CO2 emissions are generated
Solution Approach 1:
The patent uses pure oxygen instead of air as the oxidant in the reforming process. This substitution eliminates nitrogen from the combustion reaction, converting what would be nitrogen-rich flue gas into a CO2-rich stream that can be directly utilized in urea synthesis. The strong oxidation capability of pure oxygen accelerates the reforming reaction while producing a cleaner, more usable gas stream.
Solution Approach 2:
The patent converts the harmful CO2 emission into a valuable resource by directly integrating the CO2-rich stream from the reformer into the urea synthesis process. Instead of treating CO2 as waste requiring separation and sequestration, the process utilizes it as a feedstock for urea production, transforming an environmental liability into an economic and environmental asset.
2Quantity of substance
If conventional reforming processes are used, then hydrogen is produced, but the flue gas composition and pressure make integration with ammonia production difficult
Solution Approach 1:
The patent merges the reforming process with the urea synthesis process by directly connecting the CO2-rich stream from the reformer to the urea synthesis unit. This integration eliminates the need for separate CO2 capture, compression, and purification systems, simplifying the overall process flow and reducing equipment complexity while maintaining efficient hydrogen and urea production.
3Power
If air is used as the oxygen-containing stream in reforming, then combustion can proceed, but nitrogen in the flue gas reduces CO2 concentration and complicates utilization
Solution Approach 1:
The patent substitutes pure oxygen for air as the oxidant, eliminating the 79% nitrogen component that would otherwise dilute the flue gas. This results in a CO2-concentrated stream suitable for direct use in urea synthesis without requiring additional separation or concentration steps, while still providing sufficient combustion heat for the reforming reaction.
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 significantly reduces CO2 generation and simplifies the integration of flue gas into ammonia production, enhancing the efficiency of hydrogen production and CO2 sequestration, while minimizing energy consumption and reactor size.
Implementation Method 1
reacting a fuel mixture including a fuel stream, an oxygen-containing stream containing 10 vol % or less N2 relative to a volume of the oxygen-containing stream, and a recycle stream under combustion conditions including a combustion pressure of 0.7 MPa-g or more in a combustion zone within a reactor. The reacting under the combustion conditions can form a flue gas and can heat one or more surfaces in a reaction zone to a regenerated surface temperature of 600° C. or more.
Implementation Method 2
The reaction zone can include a catalyst composition. exposing a hydrocarbon-containing stream to the catalyst composition in the reaction zone at the regenerated surface temperature under reforming conditions to form a reforming product stream comprising H2 and CO.
Implementation Method 3
a pressure swing adsorption separator, the regenerator inlet being in intermittent fluid communication with the pressure swing adsorption separator
Data Source
AI summary
Systems and methods are provided for using a reverse-flew reactor (or another reactor with flows in opposing directions at different parts of a process cycle) as part of a reaction system for production of ammonia and/or urea. Using a reverse flow reactor as part of an ammonia production process can provide a variety of advantages, including direct heating of the reaction environment, and simplified generation of multiple high-purity reagent streams for ammonia and/or urea synthesis.