Intrinsic CO2 Capture via Calcium Sulfite Cycle
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Solution Overview
Problem
The production of calcium oxide (CaO) through calcining calcium carbonate (CaCO3) is energy-intensive and generates significant CO2 emissions, leading to high costs for CO2 capture and separation, and alternative methods like oxy-combustion are costly due to the need for air separation units and high operating temperatures.
Innovation Solution
Reacting sulfur dioxide (SO2) with calcium carbonate to form calcium sulfite and CO2, followed by the thermal decomposition of calcium sulfite into calcium oxide and sulfur dioxide, allowing for the intrinsic generation of high-purity CO2 and the recovery of SO2 for reuse, which is more soluble in water than CO2, facilitating its separation and utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If calcium carbonate is calcined to produce calcium oxide, then calcium oxide is obtained, but significant CO2 emissions are generated and energy consumption increases
Solution Approach 1:
The patent introduces an intermediary substance (ammonium carbonate or other carbonate salts) that mediates between the desired calcium oxide production and CO2 emission reduction. The intermediary reacts with calcium oxide to form calcium carbonate, which then decomposes to release pure CO2 for capture, while the cycle regenerates the intermediary, thus decoupling calcium oxide production from direct CO2 emissions.
Solution Approach 2:
The patent implements a recovery system where CO2 that would normally be emitted is captured and recovered. The CO2 is separated from the decomposition of calcium carbonate, purified, and stored or utilized, while the calcium oxide is regenerated and reused in the cycle, effectively recovering both the CO2 and the calcium oxide that would otherwise be lost or emitted.
2Object-generated harmful factors
If post-combustion CO2 capture systems are used to separate CO2 from flue gas, then CO2 can be captured, but capital and operating costs become very high
Solution Approach 1:
The patent uses an intermediary substance (ammonium carbonate or other carbonate salts) that enables CO2 separation through a chemical reaction cycle. The intermediary reacts with calcium oxide to form calcium carbonate, which then thermally decomposes to release concentrated CO2. This intermediary-mediated approach replaces complex post-combustion capture systems with a simpler thermal decomposition process that inherently concentrates CO2.
Solution Approach 2:
The patent changes the physical and chemical parameters of the CO2 separation process by using thermal decomposition of calcium carbonate at elevated temperatures. This parameter change (temperature increase) causes the calcium carbonate to decompose and release CO2 in a concentrated form, eliminating the need for complex low-temperature absorption and separation systems.
3Quantity of substance
If oxy-combustion is used to power the calciner, then CO2 can be concentrated, but capital and operating costs increase due to air separation units and higher temperatures
Solution Approach 1:
The patent introduces an intermediary substance (ammonium carbonate or other carbonate salts) that mediates the CO2 concentration process. Instead of using air separation units to concentrate CO2, the intermediary reacts with calcium oxide to form calcium carbonate, which then decomposes to release concentrated CO2. This intermediary-mediated concentration eliminates the need for expensive air separation equipment.
Solution Approach 2:
The patent replaces the mechanical air separation system with a chemical reaction system. Instead of using physical separation methods (mechanical systems) to concentrate CO2, the patent uses chemical reactions between carbonate salts and calcium oxide, followed by thermal decomposition, to inherently concentrate CO2 as a byproduct of the chemical cycle.
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 process reduces energy consumption and costs by generating high-purity CO2 and enabling the recovery of SO2, improving the efficiency and economics of calcium oxide production while minimizing CO2 emissions.
Implementation Method 1
reacting sulfur dioxide (SO2) with calcium carbonate to form calcium sulfite and CO2
Implementation Method 2
the thermal decomposition of calcium sulfite into calcium oxide and sulfur dioxide
Implementation Method 3
SO2 possesses a significantly greater solubility in water and/or other physical solvents than CO2, which may enable the use of physical solvents to separate SO2
Data Source
AI summary
The present invention pertains to a process for producing captured carbon dioxide. Calcium carbonate may be reacted with sulfur dioxide to produce calcium sulfite and gaseous carbon dioxide. Calcium sulfite may be thermally decomposed to produce gaseous sulfur dioxide. The processes may be used in conjunction with combusting various fuels such as a carbonaceous fuel, or a sulfurous fuel, or a nitrogenous fuel, or a hydrogen fuel, or a combination thereof.