Hydrated Lime Manufacturing via Segmentation and Inversion
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Solution Overview
Problem
Current methods for manufacturing hydrated lime struggle to produce a highly reactive and high-purity product with a high surface area, which is essential for effective flue gas treatment, as they often result in ultrafine particles that are less reactive and prone to clogging, and do not adequately remove acid gases like sulfur trioxide from flue gases.
Innovation Solution
A method involving initial grinding of lime feed to a coarse particle size, followed by removal of smaller particles, hydration, maturation as lime putty for a specified period, and flash drying to produce hydrated lime with a high BET surface area and small particle size, ensuring high reactivity and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to manufacture hydrated lime, then production is simpler and faster, but the product has lower reactivity and lower purity
Solution Approach 1:
The manufacturing process is divided into distinct stages: initial grinding to coarse particles, removal of smaller particles, hydration, maturation, and flash drying. This segmentation allows each stage to be optimized independently, producing highly reactive hydrated lime with controlled particle size distribution while managing process complexity through systematic breakdown of operations.
Solution Approach 2:
The lime feed is ground to a coarse particle size distribution before hydration, and smaller particles are removed in advance. This preliminary action ensures that only appropriately sized particles undergo hydration and maturation, preventing formation of ultrafine particles that would reduce reactivity, and establishing the foundation for high-purity product with controlled morphology.
2Area of stationary object
If ultrafine particles are produced, then surface area increases, but reactivity decreases and clogging occurs
Solution Approach 1:
Instead of grinding lime to ultrafine particles to increase surface area, the invention inverts the approach by grinding to coarse particles, removing the smallest particles, and allowing controlled formation of small particles during hydration and maturation. This produces hydrated lime with optimal particle size distribution that maintains high reactivity while achieving adequate surface area, preventing clogging issues.
Solution Approach 2:
The invention changes the particle size distribution parameters throughout the process: starting with coarse particles after initial grinding, removing particles below a certain size threshold, then allowing hydration and maturation to produce a final distribution with small but not ultrafine particles. This parameter control ensures high reactivity is maintained while surface area is sufficient for effective flue gas treatment.
3Productivity
If hydrated lime is used for flue gas treatment, then acid gas removal efficiency improves, but equipment corrosion increases without proper mitigation
Solution Approach 1:
The invention produces hydrated lime with controlled particle size and high reactivity that is highly effective for acid gas removal. The product is designed to be consumed in the scrubbing process, reacting with sulfur trioxide and other acid gases to form harmless products, thereby protecting equipment from corrosion while maintaining high productivity in flue gas treatment.
4Manufacturing precision
If high purity hydrated lime is produced, then reactivity increases, but manufacturing complexity increases
Solution Approach 1:
The invention extracts and removes smaller particles from the ground lime feed before hydration. This extraction step is crucial for achieving high purity hydrated lime, as it prevents formation of ultrafine particles and ensures consistent particle size distribution. The removal of unwanted particle sizes simplifies the overall process by preventing downstream handling issues and ensuring product quality without requiring excessively complex purification steps.
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
The method produces hydrated lime with a reactivity of 10 seconds or less in citric acid, a BET surface area greater than 30 m2/g, and a particle size of less than 44 microns, significantly improving the efficiency of acid gas removal and reducing equipment corrosion.
Implementation Method 1
feeding the fine ground lime into an air classification system; removing a refined fine lime from the air classification system wherein the refined fine lime has a particle size distribution of greater than 70% minus 200 mesh
Implementation Method 2
adding water to the refined fine lime to form damp hydrated lime
Implementation Method 3
maintaining the damp hydrated lime as a lime putty for at least 30 minutes
Implementation Method 4
flash-drying the damp hydrated lime to form dried hydrated lime
Data Source
AI summary
A method of providing highly reactive hydrated lime and the resultant lime hydrate where an initial lime feed comprising calcium and impurities is first ground to a particle-size distribution with relatively coarse particles. Smaller particles are then removed from this ground lime and the smaller particles are hydrated, allowed to mature in a damp state, and flash dried to form a hydrated lime, which is then milled to a significantly smaller particle size than that of the relatively coarse particles.