Metal Silicate Carbon Capture via Nitric Acid Leaching
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Solution Overview
Problem
Current methods for capturing and storing carbon dioxide from industrial sources, such as fossil fuel power stations, are inadequate in scale and stability, as natural sinks cannot keep up with emissions, and existing technologies face challenges in efficiently and permanently sequestering CO2 without requiring ongoing monitoring for leaks.
Innovation Solution
A process and system involving the reaction of metal silicates with nitric acid to produce metal nitrates, which are then thermally decomposed to metal oxides for scrubbing CO2 from flue gases, forming stable metal carbonates or bicarbonates that can be permanently stored, minimizing the need for ongoing monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If natural sinks (oceans, plants, rock weathering) are used to capture carbon dioxide, then no additional infrastructure is required, but the capture capacity is insufficient to keep up with current emissions volumes
Solution Approach 1:
The patent introduces an intermediary chemical system using metal silicates (such as magnesium silicate or calcium silicate) as a mediator between CO2 emissions and permanent storage. The metal silicates react with CO2 to form stable metal carbonates, serving as a chemical bridge that enables high-capacity capture beyond natural sink limitations while requiring infrastructure only at the capture and storage sites.
2Productivity
If conventional carbon capture and storage methods are used, then some carbon dioxide can be captured, but ongoing monitoring for leaks is required essentially in perpetuity
Solution Approach 1:
The patent employs metal silicate materials that permanently convert CO2 into stable carbonate minerals through chemical reaction. This disposable-like approach uses the metal silicate as a consumable reactant that permanently sequesters CO2 in a stable solid form, eliminating the need for long-term monitoring infrastructure. The converted carbonate product serves as permanent storage without requiring ongoing maintenance or monitoring.
3Reliability
If metal silicates are reacted with nitric acid to produce metal nitrates and then thermally decomposed to metal oxides for CO2 scrubbing, then carbon dioxide can be permanently stored in stable form, but the process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-processing metal silicates through reaction with nitric acid to produce metal nitrates, which are then thermally decomposed to generate highly reactive metal oxides. This preliminary preparation creates an optimized reactive material that enhances CO2 capture efficiency and product stability in the subsequent scrubbing step, ensuring reliable permanent 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 method effectively captures and permanently stores carbon dioxide from industrial sources, reducing emissions and avoiding the need for perpetual monitoring for leaks, while being economically viable and thermodynamically and geologically stable.
Implementation Method 1
reacting in a first reactor a blend, which may be a paste or slurry, of a metal silicate rock with concentrated nitric acid solution to form a paste or slurry of a metal nitrate salt
Implementation Method 2
the paste or slurry of the metal nitrate salt is then transferred to a second reactor where it is progressively heated to a temperature sufficient to decompose the metal nitrate to the metal oxide
Implementation Method 3
the gas stream is then scrubbed with slurry comprised of inter alia the hydroxides of the metals leached from the metal silicate and taken into solution by the nitric acid to form precipitates of metal carbonates
Data Source
AI summary
A process and system are disclosed for capturing carbon dioxide from a gas stream. The process and system comprise a first stage, in which a metal silicate is reacted with nitric acid to produce a metal nitrate. The metal silicate can be one or more of: an alkaline-earth metal silicate, in particular magnesium or calcium; or an alkali metal silicate, in particular lithium. The process and system also comprise a second stage, in which the metal nitrate from the first stage is heated to a temperature sufficient to decompose the metal nitrate to a metal oxide. The process and system further comprise a third stage, in which the metal oxide is mixed with water to convert the metal oxide to a metal hydroxide solution. The process and system additionally comprise a fourth stage, in which the gas stream is scrubbed with the solution from the third stage such that the metal hydroxide reacts with the carbon dioxide to form a metal carbonate/bicarbonate product.