Forced-Circulation Crystallizer Hydraulic Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing crystallizers face challenges in achieving adjustable crystal size and narrow crystal size distribution due to design difficulties and mechanical stress on crystals, leading to either moderate or coarse crystals with broad distribution.
Innovation Solution
A crystallizer design comprising two chambers with a system for maintaining supersaturation, selective circulation, and separate streams for smaller and larger crystalline particles, eliminating mechanical stress and allowing for adjustable crystal size through controlled circulation and recycling, with optional solid-liquid separation for fine particle removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a stirrer is used to create ascending movement in DTB crystallizers, then crystal circulation is improved, but mechanical destruction of crystals occurs leading to broad size distribution
Solution Approach 1:
The patent replaces the mechanical stirrer system with a circulation pump system that uses hydraulic principles instead of mechanical agitation. The pump creates controlled upward flow through the crystal bed, achieving crystal circulation and suspension without mechanical contact that would cause destruction. This substitution eliminates the broad size distribution problem while maintaining circulation efficiency.
Solution Approach 2:
The patent introduces a circulation pump as an intermediary device between the heat exchanger and the crystallizer chamber. This intermediary creates a gentle hydraulic flow field that suspends and circulates crystals without the direct mechanical impact of a stirrer, thereby preserving crystal integrity while achieving the desired circulation.
2Productivity
If forced-circulation crystallizers are used with external circuits, then crystal production is achieved, but crystal size is limited to moderate size with wide distribution
Solution Approach 1:
The patent segments the crystallizer into distinct functional zones: a heat exchange zone for supersaturation creation, a circulation zone for crystal suspension and growth, and a discharge zone for crystal removal. This segmentation allows each zone to optimize its function, with the circulation zone maintaining gentle conditions for uniform crystal growth while the heat exchange zone drives crystallization, achieving both productivity and size uniformity.
Solution Approach 2:
The patent implements dynamic control of the circulation flow rate to match crystal growth requirements. The circulation pump can adjust flow conditions to maintain crystals in suspension without excessive shear stress, allowing crystals to grow to larger, more uniform sizes while maintaining high productivity through optimized residence time in the growth zone.
3Temperature
If circulating pumps are used to convey solution, then supersaturation is achieved, but mechanical stress on crystals reduces crystal size
Solution Approach 1:
The patent extracts the crystal suspension function from the main circulation circuit and places it in a separate internal circulation zone. The external circuit handles only the liquid phase for heat exchange, while the internal zone gently suspends and circulates crystals. This separation removes mechanical stress from the crystal-laden stream while maintaining the temperature control needed for supersaturation.
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
Enables the production of crystals with adjustable size and narrow distribution without mechanical stress, reducing the risk of crystal destruction and allowing for flexible operation between different crystallizer types.
Implementation Method 1
a circuit external to this chamber for conveying said solution to be circulated, through the action of a circulating pump, from an outlet located at the bottom of said chamber to an inlet located at the top of the latter
Implementation Method 2
passing through a heat exchanger in order to create a state of supersaturation within the solution
Implementation Method 3
crystallizer for crystallizing solute contained in a solution to be treated
Data Source
AI summary
A crystallizer for crystallizing solute contained in a solution has first (2) and second (1) communicating chambers, for the solution, and a heat exchanger (20) for keeping a state of supersaturation therein. A first circuit extracts from a calm zone (15) of the latter chamber a first stream of liquid containing small crystals and recycles this stream into the first chamber. A second circuit extracts from the second chamber a second stream of liquid containing coarse crystals and brings this second stream into the first chamber. The downstream end (26) of the first circuit runs into the second circuit so that the first and second liquid streams are made to flow in the same direction into said second circuit.