Sodium Hydroxide Production via Calcium Sulfite Cycle
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Solution Overview
Problem
The production of sodium hydroxide is energy-intensive, CO2 emissions-intensive, and expensive, and existing methods are not environmentally friendly, posing challenges for reducing energy consumption, costs, and emissions, while also dealing with the environmental impact of hydrochloric acid byproducts.
Innovation Solution
A process that uses calcium sulfate as a side product to produce sodium hydroxide with low carbon emissions, employing carboxylic acid and sulfur dioxide intermediates to achieve ultra-low CO2 emissions and scalable, environmentally beneficial systems for ocean deacidification, utilizing abundant and recyclable materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the chlor-alkali process is used to produce sodium hydroxide, then sodium hydroxide can be produced, but energy consumption is high and CO2 emissions are intensive
Solution Approach 1:
The patent introduces calcium carbonate and sulfur dioxide as intermediary substances to enable sodium hydroxide production through a chemical reaction pathway that avoids direct electrical energy consumption. The reaction sequence involves calcium carbonate reacting with sulfur dioxide to form calcium sulfite, which then reacts with sodium chloride to produce sodium hydroxide, thereby mediating the transformation without requiring high energy input
Solution Approach 2:
The patent changes the fundamental reaction parameters from electrochemical (chlor-alkali process) to chemical reaction-based. By altering the production mechanism from electrical energy-driven to chemical reagent-driven, the process achieves low energy consumption while maintaining sodium hydroxide production capability
2Object-generated harmful factors
If the chlor-alkali process is used to produce sodium hydroxide, then sodium hydroxide can be produced, but CO2 emissions are intensive
Solution Approach 1:
The patent converts the harmful effect of CO2 emissions into a beneficial cycle by using sulfur dioxide (which can be captured from industrial processes) to react with calcium carbonate, forming calcium sulfite. This process captures CO2-equivalent emissions and transforms them into useful chemical intermediaries for sodium hydroxide production, thereby converting harmful emissions into beneficial products
Solution Approach 2:
The patent recovers and reuses calcium carbonate and sulfur dioxide as reactants in the chemical process. Instead of discarding these materials as waste or emissions, the process recycles them through the reaction sequence to produce sodium hydroxide, thereby eliminating CO2 emissions and reducing harmful factors
3Object-generated harmful factors
If hydrochloric acid is produced as a byproduct, then sodium hydroxide can be produced, but environmental damage occurs and CO2 emissions increase
Solution Approach 1:
The patent extracts and eliminates hydrochloric acid from the production process by replacing the chlor-alkali electrolysis method with a chemical reaction pathway using calcium carbonate and sulfur dioxide. This extraction removes the harmful byproduct at the source, preventing environmental damage and CO2 emissions associated with hydrochloric acid disposal
Solution Approach 2:
The patent converts the harmful hydrochloric acid byproduct into a beneficial process by using sulfur dioxide and calcium carbonate to form calcium sulfite, which then produces sodium hydroxide without generating strong acid byproducts. This transformation converts the harmful hydrochloric acid pathway into an environmentally friendly chemical reaction sequence
4Quantity of substance
If prior art production methods are used, then sodium hydroxide can be produced, but costs are expensive
Solution Approach 1:
The patent uses inexpensive and readily available materials such as calcium carbonate (limestone) and sulfur dioxide (from industrial flue gases) as reactants. These cheap, abundant materials replace expensive electrical energy and specialized reagents, significantly reducing production costs while maintaining sodium hydroxide output
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 energy consumption and costs, achieves negative CO2 emissions, and enables scalable carbon removal and ocean pH increase, producing high-purity carbon dioxide and avoiding strong acid byproducts.
Implementation Method 1
reacting a carbonated alkaline earth material with sulfur dioxide and water to form a sulfite
Implementation Method 2
reacting the sulfite with a carboxylic acid to form a carboxylate and sulfur dioxide
Implementation Method 3
reacting the carboxylate with sulfur dioxide and water to form the carboxylic acid and sulfite
Implementation Method 4
reacting an alkaline earth metal hydroxide with carbon dioxide to form a carbonated alkaline earth material
Data Source
AI summary
The present application pertains to processes producing oxides using a weak acid intermediate. In one embodiment a material comprising calcium carbonate is reacted with a solution comprising aqueous carboxylic acid to form a gas comprising carbon dioxide and a solution comprising aqueous calcium carboxylate. The solution comprising aqueous calcium carboxylate is reacted with sodium sulfate to form a solution comprising aqueous sodium carboxylate and a solid comprising calcium sulfate. The solution comprising aqueous sodium carboxylate is reacted with sulfur dioxide to form sodium sulfite and an aqueous carboxylic acid. The sodium sulfite is separated from said aqueous carboxylic acid and reacted to form a solid comprising calcium sulfite which is decomposed to form calcium oxide and sulfur dioxide.