Integrated Ammonia–Nitric Acid Process With Ammonia Buffering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of ammonia and nitric acid is challenged by the inflexibility of processes powered by renewable energy sources, leading to fluctuations in hydrogen production, which affects the entire process efficiency and profitability, and requires costly energy storage solutions.
Innovation Solution
A method for controlling an integrated ammonia-nitric acid process that switches between modes of operation based on available power, storing excess ammonia during high availability and using it during low availability, with thermal and electric power transfer between processes to maintain consistent output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the process is powered by renewable energy sources, then the carbon footprint is reduced, but the process flexibility deteriorates due to fluctuations in energy availability
Solution Approach 1:
The patent applies preliminary action by producing and storing ammonia during periods of high renewable energy availability before the fluctuations occur. The ammonia storage unit accumulates excess ammonia when energy is abundant, allowing the process to continue operating during periods of low energy availability without external intervention, thus resolving the flexibility issue while maintaining low carbon footprint
Solution Approach 2:
The patent changes the operational parameters by switching between different production modes (first mode with high ammonia production and storage, second mode with adjusted production) based on renewable energy availability. This dynamic parameter adjustment allows the process to adapt to fluctuating energy inputs while maintaining consistent output, resolving the contradiction between renewable energy usage and process flexibility
2Productivity
If hydrogen production is increased to meet demand, then ammonia production increases, but the process efficiency deteriorates due to fluctuations in renewable energy availability
Solution Approach 1:
The patent implements feedback control by monitoring renewable energy availability and adjusting hydrogen production rates accordingly. The system receives feedback on energy input and modulates the water electrolysis rate to match actual availability, preventing inefficiency from producing more hydrogen than can be processed while ensuring continuous ammonia production, thus maintaining both productivity and efficiency
Solution Approach 2:
The system performs preliminary action by storing excess ammonia during high-energy periods before efficiency deteriorates can occur. This advance storage ensures that when energy availability drops and production must be reduced, the system can maintain stable output by drawing from stored ammonia, thereby preserving process efficiency while meeting demand
3Stability of the object's composition
If energy storage solutions are installed to buffer fluctuations, then process stability improves, but the capital cost increases
Solution Approach 1:
The patent uses ammonia as an intermediary energy storage medium rather than installing complex electrical energy storage systems. The ammonia storage unit acts as a mediator that converts electrical energy fluctuations into chemical energy storage, providing process stability without requiring expensive batteries or other electrical storage infrastructure, thus achieving stability while minimizing capital cost
Solution Approach 2:
The system applies self-service by using the process itself (ammonia production) to provide the storage function. The ammonia produced during high-energy periods serves as the storage medium, eliminating the need for separate energy storage systems. This self-service approach provides process stability while avoiding the capital costs of external storage infrastructure
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 enhances process flexibility, reduces capital costs for hydrogen and energy storage, and maintains consistent production of ammonia, nitric acid, and optionally ammonium nitrate, even with fluctuating renewable energy sources.
Implementation Method 1
hydrogen is produced from electrolysis of water
Implementation Method 2
conversion to ammonia in a suitable catalytic converter
Implementation Method 3
Heat is normally recovered from the process, e.g. from the hot reforming effluent and from the ammonia converter, in the form of steam
Implementation Method 4
Steam at a sufficient pressure may be expanded in a steam turbine to produce energy
Implementation Method 5
The stored ammonia is combusted when the amount of renewable energy is low. Thereby heat is produced which is converted into electricity.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An integrated process for the synthesis of ammonia and nitric acid, including the production of hydrogen from electrolysis of water, is controlled by a selective switching between a first mode of operation and a second mode of operation, wherein in the first mode of operation ammonia is produced in excess and is stored in a suitable ammonia storage; in the second mode of operation the ammonia from said ammonia storage is used to provide an additional input of ammonia to the production of nitric acid; the switching between said first mode and second mode is based on the amount of power which is transferred to the electrolysis of water.