Flash Calcined Lime Hydrate Reactivity
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Solution Overview
Problem
Traditional methods for producing calcium hydroxide fail to consistently achieve high reactivity necessary for effective acid gas mitigation, as they rely on surface area proxies like BET surface area, which do not accurately predict reactivity, especially in dry injection processes, and require complex manufacturing processes to produce highly reactive hydrate (HRH) compositions.
Innovation Solution
A method involving flash calcination to produce calcium oxide, which is then mixed with traditionally calcined calcium oxide, slaked with water, and processed to create calcium hydroxide with enhanced reactivity and BET surface area, allowing for the production of High Reactivity Hydrate (HRH) and Super Reactive Hydrate (SRH) compositions using conventional manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lime kiln calcination is used to produce calcium oxide, then the manufacturing process is simple and well-established, but the resulting calcium hydroxide does not achieve sufficiently high reactivity for effective acid gas mitigation
Solution Approach 1:
The patent changes the calcination parameters by introducing flash calcination as an alternative to traditional lime kiln calcination. Flash calcination uses rapid heating at lower temperatures (below 900°C) compared to traditional methods, which operate at higher temperatures (above 900°C). This parameter change in the calcination process produces calcium oxide with different surface properties that enhance the reactivity of the resulting calcium hydroxide, achieving reaction times under 10 seconds while maintaining manufacturing feasibility
Solution Approach 2:
The patent creates a composite calcium oxide material by mixing flash calcined calcium oxide with traditionally calcined calcium oxide in specific ratios. This composite approach combines the high reactivity benefits of flash calcined material with the manufacturing simplicity and consistency of traditional methods, producing calcium hydroxide that achieves both high reactivity (reaction time < 10 seconds) and manufacturing practicality
2Reliability
If flash calcination is used to produce highly reactive calcium oxide, then calcium hydroxide reactivity is significantly enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-mixing the flash calcined and traditionally calcined calcium oxide in optimal ratios before the slaking process. This preliminary blending ensures that the reactive components are properly distributed in advance, allowing the subsequent calcium hydroxide production to achieve consistent high reactivity without requiring complex real-time process control or specialized equipment during the main manufacturing operation
Solution Approach 2:
The patent uses traditionally calcined calcium oxide as an intermediary material that bridges the gap between flash calcined calcium oxide and the final calcium hydroxide product. This intermediary component provides manufacturing stability and process familiarity while the flash calcined portion contributes the enhanced reactivity, effectively mediating between the conflicting requirements of high performance and simple manufacturing
3Difficulty of detecting and measuring
If BET surface area is used as a proxy to predict reactivity, then measurement is simplified, but the prediction accuracy for actual acid gas mitigation performance is insufficient
Solution Approach 1:
The patent substitutes the mechanical/BET surface area measurement approach with a chemically-based reactivity test method. Instead of relying on surface area measurements that do not accurately predict performance, the invention uses a citric acid reaction time test that directly measures the chemical reactivity of calcium hydroxide particles. This substitution replaces an indirect physical measurement with a direct chemical performance measurement, achieving both measurement simplicity and prediction accuracy by defining HRH as having a reaction time of less than 10 seconds in the citric acid test
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 enables the production of calcium hydroxide with reactivity times under 10 seconds and BET surface areas above 20 m2/g, effectively addressing the limitations of traditional methods by enhancing acid gas reactivity without the need for modified manufacturing processes, making the calcium hydroxide suitable for applications requiring rapid neutralization.
Implementation Method 1
forming a calcium oxide particulate in a flash calciner
Implementation Method 2
slaking said calcium oxide particulate mixture with water to form calcium hydroxide particles
Data Source
AI summary
A system and related methods for the production of lime sorbent compositions from a calcium carbonate feedstock formed using flash calcination to produce the intermediate calcium oxide material.