Primary Reformer Oxygen-Enriched Air Integration
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Solution Overview
Problem
The ammonia synthesis process has high carbon dioxide emissions and requires costly equipment due to the need for oxygen enrichment and compression, leading to thermal duty unbalances between primary and secondary reformers, especially when using water electrolysis for green hydrogen production.
Innovation Solution
A method that involves using oxygen-enriched air from water electrolysis in the primary reformer burners to increase flame temperature and reduce fuel consumption, allowing direct oxygen feeding without compression, and mixing hydrogen with the CO2-depleted gas stream to optimize reforming efficiency and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If oxygen-enriched air is fed to the secondary reformer to reduce energy consumption and CO2 emissions, then energy consumption and CO2 emissions are reduced, but the temperature of reforming gases leaving the secondary reformer rises, requiring reduction of primary reformer outlet temperature which lowers natural gas conversion rate
Solution Approach 1:
The patent introduces an intermediary substance (carbon dioxide) to mediate the thermal balance between primary and secondary reformers. By injecting CO2 from the CO2 removal section into the primary reformer inlet, the system can reduce secondary reformer temperature without compromising primary reformer conversion efficiency, thus resolving the contradiction between energy reduction and productivity maintenance
Solution Approach 2:
The patent changes the composition parameter of the reformer feed gas by adding CO2 to the primary reformer inlet stream. This parameter change allows thermal duty redistribution that maintains optimal conversion rates in the primary reformer while reducing excessive temperatures in the secondary reformer, thereby preserving productivity while reducing energy consumption
2Loss of energy
If oxygen-enriched air is fed to the secondary reformer, then energy consumption is reduced, but thermal duty unbalance occurs between primary and secondary reformers
Solution Approach 1:
CO2 injection into the primary reformer acts as a thermal mediator that redistributes heat duties between reformers. The CO2 absorbs heat in the primary reformer and modulates the thermal profile, enabling the system to operate with oxygen-enriched air in the secondary reformer while maintaining overall thermal duty balance
Solution Approach 2:
The system implements a feedback mechanism where CO2 from the CO2 removal section (downstream) is fed back to the primary reformer inlet (upstream). This feedback loop dynamically balances thermal duties between reformers, compensating for the thermal effects of oxygen enrichment in the secondary reformer
3Object-generated harmful factors
If water electrolysis is used for green hydrogen production, then CO2 emissions are reduced, but costly compression and storage units are required due to pressure mismatch
Solution Approach 1:
The patent merges the water electrolysis unit with the existing reformer system by directly integrating the hydrogen and oxygen streams into the reformer feed and combustion air. This integration eliminates the need for separate compression and storage units, as the electrolysis products are directly utilized in the reforming process at compatible pressures
Solution Approach 2:
The electrolysis unit serves multiple functions simultaneously: producing green hydrogen for the reformer feed, providing oxygen for combustion air enrichment, and enabling CO2 emission reduction. This multi-functionality reduces the need for additional dedicated equipment for compression and storage
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 carbon dioxide emissions by 5% and lowers fuel consumption, eliminates the need for costly compression and storage units, and maintains thermal balance between reformers, while enhancing plant productivity and reducing energy costs.
Implementation Method 1
providing the primary reforming heat in the burners of a steam methane reformer (SMR) through the combustion reactions between the fuel and the oxygen-enriched air obtained by mixing air with the oxygen stream from the water electrolysis
Implementation Method 2
SMR is a type of fired tubular steam reformer wherein a gas mixture of hydrocarbons is partially converted to syngas following an endothermic reaction between the hydrocarbons and steam
Implementation Method 3
preparing a hydrogen stream and an oxygen stream by water electrolysis
Data Source
AI summary
Method for preparing a synthesis gas suitable for the synthesis of ammonia or methanol, the method comprises the step of feeding to the radiant portion of a primary reformer an oxygen-enriched air obtained by mixing air with an oxygen stream generated by water electrolysis.