Allulose Crystallization Under Reduced Pressure
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Solution Overview
Problem
Conventional methods for preparing crystalline allulose face challenges such as high energy consumption, degradation reactions, and the formation of fines due to temperature gradients, which hinder continuous industrial-scale production and result in unsatisfactory yield and crystal quality.
Innovation Solution
A process involving crystallization under reduced pressure at moderate temperatures (around 45°C) with continuous supply of fresh aqueous mother liquor maintains constant viscosity and supersaturation, optimizing crystal size and yield, and minimizing degradation, while using seed crystals in alcoholic mediums for improved mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional evaporation crystallization is used, then crystalline allulose can be obtained, but high energy consumption occurs due to high temperature requirements
Solution Approach 1:
The patent applies parameter changes by operating at reduced pressure (40-500 mbar) to lower the crystallization temperature from conventional high temperatures to moderate temperatures (20-80°C). This pressure-temperature parameter change allows crystallization to occur at energy-efficient conditions while maintaining crystal quality, directly resolving the contradiction between energy consumption and manufacturing precision
Solution Approach 2:
The patent utilizes phase transitions by controlling the evaporation of water from the aqueous mother liquor under reduced pressure. The phase change from liquid water to vapor occurs at lower temperatures under vacuum conditions, enabling crystallization at moderate temperatures and reducing energy consumption while maintaining effective crystal formation
2Productivity
If high temperature evaporation is used to induce crystallization, then crystallization rate increases, but degradation reactions occur
Solution Approach 1:
The patent changes the pressure parameter to reduced pressure (40-500 mbar), which allows the system to achieve high crystallization rates at moderate temperatures (20-80°C) rather than high temperatures. This parameter change decouples crystallization rate from temperature, enabling fast crystallization without degradation reactions
Solution Approach 2:
The patent converts the harmful effect of reduced pressure (which could cause excessive evaporation and concentration) into a beneficial effect by using it to lower the boiling point and enable controlled evaporation at moderate temperatures. This allows rapid crystallization through controlled supersaturation without the harmful high-temperature degradation
3Productivity
If rapid cooling is used to induce crystallization, then crystallization speed increases, but temperature gradients form causing fines
Solution Approach 1:
The patent applies preliminary action by maintaining the aqueous mother liquor at a constant moderate temperature (20-80°C) before and during crystallization induction. This preliminary temperature stabilization prevents thermal shocks and gradients that would cause fines, while the reduced pressure environment enables rapid crystallization to proceed uniformly
Solution Approach 2:
The patent changes the pressure parameter to reduced pressure, which enables rapid crystallization through controlled supersaturation without requiring rapid cooling. This alternative parameter change achieves high crystallization speed while maintaining thermal uniformity and preventing fine crystal formation
4Ease of operation
If continuous supply of fresh mother liquor is used, then viscosity remains constant improving mixing, but process complexity increases
Solution Approach 1:
The patent applies continuity of useful action by implementing a continuous supply of fresh aqueous mother liquor during the crystallization process. This continuous flow maintains constant viscosity and supersaturation levels, ensuring uniform mixing and crystal growth throughout the process, while the automated continuous operation actually simplifies overall process control compared to batch methods
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 method enhances crystallization rates, reduces energy consumption, and produces allulose crystals with improved size distribution and quality, suitable for continuous or semi-continuous industrial processes with reduced by-products and minimal seed usage.
Implementation Method 1
conventional processes for obtaining crystalline allulose, crystallization is induced by evaporating solvent (water) and/or cooling the solution
Implementation Method 2
maintaining, preferably until the end of crystallization, the vapor phase above the aqueous mother liquor within the evaporating crystallizer at a crystallization pressure within the range of from 40 to 500 mbar
Implementation Method 3
maintaining, preferably until the end of crystallization, the aqueous mother liquor within the evaporating crystallizer at a crystallization temperature within the range of from 20 to 80° C.
Implementation Method 4
inducing crystallization of allulose from the aqueous mother liquor at the crystallization temperature and at the crystallization pressure in a supersaturated state thereby obtaining the solid allulose material as a precipitate
Implementation Method 5
inducing crystallization of allulose from the aqueous mother liquor at the crystallization temperature and at the crystallization pressure in a supersaturated state
Data Source
AI summary
The invention relates to a process for the preparation of a solid allulose material comprising crystalline allulose, the method comprising the steps of (a) providing in an evaporating crystallizer an aqueous mother liquor containing dissolved allulose; (b) maintaining, preferably until the end of crystallization, the aqueous mother liquor within the evaporating crystallizer at a crystallization temperature within the range of from 20 to 80° C.; (c) maintaining, preferably until the end of crystallization, the vapor phase above the aqueous mother liquor within the evaporating crystallizer at a crystallization pressure within the range of from 40 to 500 mbar; and (d) inducing crystallization of allulose from the aqueous mother liquor at the crystallization temperature and at the crystallization pressure in a supersaturated state thereby obtaining the solid allulose material as a precipitate and a supernatant.