Xylitol Crystal Preparation for Stable Large-Particle Crystallization

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Solution Overview

Problem

Existing xylitol crystallization processes face issues such as time-consuming operations, severe secondary nucleation, high fine powder content, significant product variations between batches, and unstable crystallization, leading to caking of xylitol products due to unreasonable process parameters and lack of theoretical basis for adding crystal seeds.

Innovation Solution

A preparation system and method involving a series of interconnected tanks and units, including blending, decolorization, ion exchange, nanofiltration, evaporation, crystallization, centrifugation, and drying, optimized with controlled vacuum, temperature, and seed addition to enhance particle size and reduce secondary nucleation, resulting in larger xylitol crystals with improved caking cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If evaporation crystallization or cooling crystallization is used with conventional process parameters, then xylitol crystals can be obtained, but the crystallization process is time-consuming and produces severe secondary nucleation with high fine powder content

Engineering Contradiction:
Improvecrystallization speedVSAvoidparticle size distribution
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by optimizing crystallization temperature, adding crystal seeds at specific supersaturation levels, and controlling evaporation rates to achieve faster crystallization with reduced secondary nucleation and improved particle size distribution

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements preliminary action by pre-cooling the xylitol solution before crystallization and preparing crystal seeds in advance, which allows the crystallization process to start under optimal conditions and reduces induction time while controlling nucleation

Inventive Principle:
Principle #10Preliminary action

2Productivity

If crystal seeds are added based on experience without theoretical basis, then crystallization can proceed, but the process is unstable with significant product variations between batches

Engineering Contradiction:
Improvecrystallization efficiencyVSAvoidbatch consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback control by monitoring supersaturation levels during crystallization and adjusting process parameters accordingly, ensuring consistent crystal growth conditions across batches and reducing product variation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces empirical mechanical judgment with theoretical calculations based on solubility curves and supersaturation models, allowing precise determination of crystal seed addition timing and quantity for reliable batch-to-batch consistency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional crystallization processes are used, then xylitol crystals are produced, but caking occurs due to fine powder content and unstable crystallization

Engineering Contradiction:
Improveproduct stabilityVSAvoidcaking phenomenon
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent changes process parameters including final crystallization temperature, drying conditions, and particle size control to produce larger, more uniform crystals with reduced fine powder content, thereby preventing caking and improving product stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of supersaturation-induced secondary nucleation into a benefit by carefully controlling supersaturation levels to promote primary crystal growth while minimizing unwanted nucleation, resulting in better crystal quality and reduced caking

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 method produces xylitol crystals with a higher proportion of 30-mesh particles and extends the caking cycle from 45 days to over 100 days, achieving more stable and efficient crystallization.

Implementation Method 1

a decolorization tank (2), an ion exchange column (3), a nanofiltration system (4) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

an ion exchange column (3), a nanofiltration system (4) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 3

a nanofiltration system (4), a first evaporator (5) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectNanofiltration: Semipermeable Membrane

Implementation Method 4

a nanofiltration system (4), a first evaporator (5) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 5

a first evaporator (5), a first crystallization kettle (6) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 6

a first crystallization kettle (6), a first centrifuge (7) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 7

a first centrifuge (7), a hot air drying tank (8) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectHot air drying: Heating

Implementation Method 8

a hot air drying tank (8), and a first fluidized bed dryer (9) that are sequentially connected through pipelines

Methodology Applied
Scientific EffectFluidized bed drying: Fluidisation

Data Source

PatentEP4424660B1Preparation system and method for xylitol crystal
Publication Date: 2026.02.25 ZHEJIANG HUAKANG PHARMA
  • EP4424660B1 patent drawingFigure 1
  • EP4424660B1 patent drawingFigure 2

AI summary

The present disclosure provides a preparation system and a preparation method for xylitol crystals. In the preparation system, outlets of a first centrifuge are connected with an inlet of a hot air drying tank and an inlet of a primary mother liquor storage tank through pipelines, respectively. Outlets of a second centrifuge are connected with an inlet of a second fluidized bed dryer and an inlet of a secondary mother liquor storage tank through pipelines, respectively. An outlet of a dicrystalline sugar dissolution tank is connected with an inlet of a blending tank through a pipeline. An outlet of a tricrystalline sugar dissolution tank is connected with the inlet of the primary mother liquor storage tank. The blending tank is provided with an inlet for a raw material of xylitol hydrogenation solution. An output of an outlet of a first fluidized bed dryer is prepared xylitol crystals.