Multi-Tank Crystal Purification With Mother Liquor Feedback

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Solution Overview

Problem

Existing purification techniques fail to achieve high-yield and low-cost production of high-purity compounds, particularly for organic compounds forming small particles or low-purity crude solutions, leading to increased operating and equipment costs.

Innovation Solution

A purification apparatus with a configuration of N tanks connected in series, including a crystallization tank and optionally a ripening tank, utilizes solid-liquid separators to send slurry upstream and return mother liquor to previous tanks, reducing the amount of low-purity residue and washing liquid, thereby enhancing purity and yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If gravity settling wash column is used for purification, then purification process is simple, but purification effect is insufficient for small particle size crystals or low purity crude compounds

Engineering Contradiction:
Improvepurification process complexityVSAvoidpurification effect
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The purification system is segmented into multiple functional units: crystallization tank, solid-liquid separator, wash column, and mother liquor return lines. This segmentation allows each component to perform its specific function optimally, with the solid-liquid separator handling particle separation and the wash column providing additional purification, thereby resolving the contradiction between simple process design and effective purification for small particle sizes

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A solid-liquid separator is introduced as an intermediary component between the crystallization tank and the wash column. This intermediary device efficiently separates crystals from mother liquor, improving the purification effect for small particle size crystals without significantly increasing overall system complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If multiple crystallization tanks with solid-liquid separators and mother liquor return lines are used, then purification effect and yield are improved, but equipment complexity and investment cost increase

Engineering Contradiction:
Improvecompound purityVSAvoidequipment structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Mother liquor return lines create a feedback mechanism where purified mother liquor from downstream tanks is returned to upstream tanks. This feedback loop enhances purification efficiency and compound yield by allowing multiple passes through the system, while the modular tank design keeps equipment complexity manageable

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Multiple crystallization tanks are merged into a series configuration where each tank performs similar crystallization and separation functions. This merging approach achieves high purification effectiveness through cumulative effect while maintaining relatively simple equipment structure by using identical modular units

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If high purity crude compound solution is used to achieve high yield in crystallization, then crystallization yield is improved, but precrystallization purification cost increases

Engineering Contradiction:
Improvecrystallization yieldVSAvoidpurification cost
Core Design Contradiction:
ProductivityVSUse of energy by stationary object

Solution Approach 1:

The system uses self-service through mother liquor return lines where purified mother liquor automatically flows back to previous tanks without requiring additional purification steps. This self-service mechanism maintains high crystallization yield while avoiding increased precrystallization purification costs by utilizing the existing system infrastructure

Inventive Principle:
Principle #25Self-service

4Manufacturing precision

If crystals are melted and mother liquor is discharged during crystallization, then purification is achieved, but equipment complexity and energy consumption increase

Engineering Contradiction:
Improvecompound purityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The system discards only the necessary mother liquor portions while recovering and returning purified mother liquor to previous tanks. This selective discarding and recovering approach achieves purification without excessive energy consumption, as the mother liquor return lines enable reuse of purified liquid without requiring complete melting and reprocessing

Inventive Principle:
Principle #34Discarding and recovering

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 apparatus achieves high-purity compounds in high yield with reduced crystallization residue and operating costs, especially effective for compounds with small particle sizes or low purity, by optimizing the use of solid-liquid separators and countercurrent contact of mother liquor with crystals.

Implementation Method 1

a 1st tank is a crystallization tank including a cooling mechanism

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 2

a 1st tank is a crystallization tank including a cooling mechanism

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 3

the crystals sent from the crystallization tank are gravity-settled in the purification column

Methodology Applied
Scientific EffectGravitational settling: Gravitation

Implementation Method 4

a portion of the crystals heated and melted by the heater at the lower part of the purification column

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 5

a wash column including a circulation pump that circulates a washing liquid

Methodology Applied
Scientific EffectHydraulic circulation: Hydraulic Press

Implementation Method 6

a portion of the crystals heated and melted by the heater at the lower part of the purification column

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4249095B1Purification device
Publication Date: 2026.01.21 NIPPON SHOKUBAI CO LTD
  • EP4249095B1 patent drawingFigure 1~3
  • EP4249095B1 patent drawingFigure 4~6
  • EP4249095B1 patent drawingFigure 7~8

AI summary

The present invention aims to provide a compound purification apparatus capable of providing a high purity compound in high yield and at low cost. The present invention relates to an apparatus for purifying a compound, the purification apparatus including: a crystallizing unit including a crystal forming section; and a wash column including a mechanism that forcibly transfers crystals, the crystallizing unit including N tanks connected in series, wherein N is 2 or greater, a 1st tank is a most downstream tank, a (N)th tank is a most upstream tank, at least the 1st tank is a crystallization tank including a cooling mechanism, and a 2nd and subsequent tanks are each a crystallization tank or a ripening tank, the purification apparatus including a line that feeds a compound-containing liquid to be purified to at least one of the N tanks, the wash column including: a line that sends a product out; and a line that returns a mother liquor to the crystallizing unit, with the line that returns a mother liquor to the crystallizing unit being connected to at least the (N)th tank, the crystallizing unit including: a line that feeds a slurry from the (N)th tank to the wash column; a line that sends a slurry from a tank among the 1st to (N - 1)th tanks to the next upstream tank; and a line that is provided to each of the 1st to (N - 1)th tanks and that sends thereto a mother liquor withdrawn from an upstream tank, wherein at least one of the lines that send a slurry from a tank among the 1st to (N - 1)th tanks to the next upstream tank is a line that sends a slurry from a tank to the next upstream tank via a solid-liquid separator and that has a line that returns a mother liquor from which crystals are removed in the solid-liquid separator to the tank where the slurry came from, and wherein the line that is provided to each of the 1st to (N - 1)th tanks and that sends thereto a mother liquor withdrawn from an upstream tank is a line that directly sends a mother liquor withdrawn from a tank one upstream or a line that sends a mother liquor withdrawn from a tank one upstream via a solid-liquid separator, the purification apparatus further including a line that sends a mother liquor to the outside of the purification apparatus.