Fluidized Bed LiOH-to-Li2S Conversion Without Solvent Recovery
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Solution Overview
Problem
The current process for converting lithium hydroxide (LiOH) to lithium sulfide (Li2S) is inefficient and costly due to the need for additional processing steps and solvent recovery in a wet process, which complicates the production and increases costs.
Innovation Solution
A continuous process using a fluidized bed reactor system that directly converts anhydrous LiOH to Li2S, incorporating a side stripper for moisture and excess hydrogen sulfide removal, and a solids recovery system to achieve high purity Li2S production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wet process is used to convert LiOH to Li2S, then the reaction can be carried out at mild temperatures, but additional processing steps are required for solvent separation and recovery, increasing process complexity and cost
Solution Approach 1:
The invention extracts and eliminates the solvent from the reaction system, transitioning from a wet process to a dry process. This removes the need for solvent separation and recovery steps while maintaining reaction effectiveness through direct solid-state reaction between LiOH and H2S.
Solution Approach 2:
The invention changes the physical state parameters of the reaction system by using anhydrous conditions and elevated temperatures (above the melting point of LiOH). This parameter change enables a simpler process configuration without requiring solvent management infrastructure.
2Reliability
If a wet process with solvent is used, then the reaction proceeds effectively, but additional equipment and steps are needed for solvent recovery, increasing capital expenditure
Solution Approach 1:
The solvent is completely removed from the reaction system, replacing it with a dry solid-state reaction approach. This eliminates all equipment related to solvent handling, separation, and recovery, reducing capital expenditure while maintaining reaction effectiveness through direct contact between reactants.
Solution Approach 2:
The invention replaces the mechanical solvent-based reaction medium with a solid-state reaction mechanism driven by heat and direct contact. This substitution eliminates the need for complex liquid handling and separation equipment.
3Productivity
If a wet process is used, then Li2S can be produced, but the process requires solvent separation steps that increase operational costs
Solution Approach 1:
By removing the solvent from the process, the invention eliminates the energy-intensive steps of solvent evaporation, condensation, and recovery. The dry process requires only heating to maintain reaction temperature, significantly reducing overall energy consumption while maintaining Li2S production capability.
4Manufacturing precision
If additional processing steps are added for solvent recovery, then product purity can be maintained, but process time and complexity increase
Solution Approach 1:
The invention extracts the source of contamination (solvent) from the process, eliminating the need for multiple purification and separation steps. Product purity is maintained through the inherent cleanliness of the dry reaction system, reducing both process time and complexity.
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 system enables high-purity Li2S production exceeding 95 wt% with reduced energy consumption and capital expenditure, eliminating the need for additional solvent separation steps, thus providing a more efficient and economical solution.
Implementation Method 1
contact the feed of anhydrous LiOH with hydrogen sulfide (H2S) to produce lithium sulfide (Li2S)
Implementation Method 2
the side stripper configured to strip the effluent stream that may include Li2S of moisture, excess H2S, or both
Implementation Method 3
a fluidized bed reactor configured to continuously receive a feed of anhydrous LiOH and contact the feed of anhydrous LiOH with hydrogen sulfide (H2S)
Data Source
AI summary
A process and system for continuously converting anhydrous LiOH into Li2S by reacting with a sulfur containing gas such as H2S using a fluidized bed reactor with one or more internals. The process may include a solids recovery system to recycle fines and excess sulfur containing gas to the reactor. The process may include a side stripper to strip Li2S product of excess sulfur containing gas and moisture that can be recycled to the fluidized bed reactor.