D-Allulose Crystallization with Nanofiltration Dimer Removal
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Solution Overview
Problem
Existing processes for producing D-allulose crystals suffer from low overall yield, instability, and the formation of anti-crystallizing impurities, particularly D-allulose dimers, which hinder continuous and efficient production.
Innovation Solution
Incorporating a nanofiltration step before the concentration process to remove D-allulose dimers, followed by a crystallization step using an adiabatic evaporative cooling method to stabilize the process and enhance yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chromatography is used to separate D-allulose from the epimerization mixture, then D-allulose purity is improved, but production complexity and cost increase
Solution Approach 1:
The patent extracts and removes harmful impurities (D-allulose dimers and other anti-crystallizing substances) from the reaction mixture before crystallization using nanofiltration membranes. This selective extraction of harmful components simplifies the overall process by eliminating the need for complex chromatography while maintaining high crystal purity and yield.
Solution Approach 2:
The patent changes the physical-chemical parameters of the system by using nanofiltration membranes with specific pore sizes and charge characteristics to selectively remove dimers based on their size and charge properties. This parameter-based separation approach replaces complex chromatographic methods with a simpler membrane filtration process.
2Productivity
If spray-drying is used to produce D-allulose powder, then production speed is improved, but product quality deteriorates due to impurities and hygroscopicity
Solution Approach 1:
The patent performs preliminary purification of the D-allulose solution by removing dimers and anti-crystallizing impurities through nanofiltration before the crystallization and drying steps. This preliminary action ensures that subsequent spray-drying or crystallization produces high-quality product without the need for rework or additional purification steps.
Solution Approach 2:
The patent converts the harmful effect of dimers (which cause non-centrifugable massecutes and poor crystal quality) into a benefit by using their presence as an indicator to optimize the nanofiltration process parameters, thereby achieving better separation and higher crystal purity.
3Productivity
If recycling of mother liquors is implemented, then overall yield is improved, but dimer content increases causing process instability
Solution Approach 1:
The patent implements continuous nanofiltration to remove dimers throughout the process, including from recycled mother liquors. This continuous removal of harmful substances maintains process stability even when recycling is employed, allowing sustained high yield without the instability that would normally result from dimer accumulation.
Solution Approach 2:
The patent introduces nanofiltration membranes as an intermediary between the mother liquor recycling stream and the crystallization process. This intermediary component selectively removes dimers and other impurities from the recycled stream, allowing recycling to proceed without compromising process stability.
4Device complexity
If conventional crystallization is used without dimer removal, then process simplicity is maintained, but crystal quality deteriorates with high dimer content
Solution Approach 1:
The patent replaces complex mechanical separation systems (centrifugation, filtration) with nanofiltration membrane technology that can selectively remove dimers based on size and charge. This substitution achieves better crystal quality while maintaining or even simplifying the overall process flow.
Solution Approach 2:
The patent uses porous nanofiltration membranes with controlled pore sizes and surface charges to selectively retain D-allulose dimers while allowing monomeric D-allulose to pass through. This porous material-based separation achieves high crystal purity without complex processing steps.
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 process achieves an overall yield exceeding 25% relative to D-fructose introduced, with D-allulose crystals having a low D-allulose dimer content, enabling stable and continuous production at a competitive price.
Implementation Method 1
at least one nanofiltration step, said step taking place in a step prior to the step of concentrating the composition rich in D-allulose
Implementation Method 2
a crystallization step using an adiabatic evaporative cooling method
Implementation Method 3
a crystallization step using an adiabatic evaporative cooling method
Implementation Method 4
a step of crystallizing the stock solution so as to form D-allulose crystals and mother liquors
Data Source
AI summary
A new method for producing D-allulose crystals that allows for a continuous production process and ensures a high yield. Also, new D-allulose crystals. Further, the use of a nanofiltration unit in a method for producing D-allulose crystals to improve the yield and/or quality of the resulting crystals.