Lactose Refiner Countercurrent Washing System
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Solution Overview
Problem
Lactose crystals produced from deproteinized cheese whey or skim milk often contain high levels of ash and protein, failing to meet commercial and governmental standards of identity, and tend to adsorb riboflavin, resulting in an undesirable yellow color, which requires refining to reduce impurities and improve appearance.
Innovation Solution
A countercurrent washing system is employed, utilizing a recirculating wash medium and screens to separate lactose crystals from impurities, allowing for efficient purification and reduced operator intervention by discharging washed lactose crystals downstream with minimal impurities and wash medium, thereby achieving higher purity and whiteness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-stage washing of lactose crystals is performed using gravity settling, then purification effectiveness is improved, but operator intervention is required to maintain high crystal density
Solution Approach 1:
The system employs a density-based separation mechanism where the wash medium and crystal slurry automatically stratify based on density differences. The wash medium, being less dense, naturally rises to the top while the crystal slurry settles to the bottom, eliminating the need for operator intervention to maintain density stratification. This self-service approach maintains purification effectiveness while reducing operational complexity.
Solution Approach 2:
The invention replaces manual or mechanically-controlled density maintenance systems with a passive density-based separation system. By utilizing the inherent density differences between the wash medium and crystal slurry, the system achieves automatic separation without requiring operators to actively manage crystal density, thus improving ease of operation while maintaining manufacturing precision.
2Manufacturing precision
If gravity settling is used to separate lactose crystals from wash medium, then separation is achieved, but wash medium containing impurities is discharged with crystals
Solution Approach 1:
The system extracts and removes the wash medium from the crystal stream at an intermediate point in the process, before the crystals are discharged. By separating the wash medium removal function from the crystal discharge function, the system prevents impurity-containing wash medium from being discharged with the crystals, thereby reducing loss of substance while maintaining separation efficiency.
Solution Approach 2:
The discharge system is segmented into separate streams: one for crystals and one for wash medium. The crystal discharge occurs from the bottom of the settling zone, while the wash medium is removed separately from the top or intermediate zones. This segmentation ensures that impurities contained in the wash medium do not accompany the discharged crystals, resolving the contradiction between separation efficiency and impurity discharge.
3Manufacturing precision
If conventional washing systems are used, then lactose crystals are washed, but substantial operator attention is required to achieve reasonable effectiveness
Solution Approach 1:
The system is designed to automatically maintain optimal operating conditions through density-based separation. The natural density differences between wash medium and crystal slurry drive the separation process without requiring operator monitoring or adjustment, thereby achieving reasonable refining effectiveness with minimal operator attention and increasing automation.
Solution Approach 2:
The system incorporates implicit feedback through the density-based separation mechanism. As crystals are washed and impurities removed, the density of the remaining slurry changes, which automatically adjusts the separation efficiency. This self-regulating feedback loop maintains refining effectiveness without requiring external operator control, reducing the extent of automation needed.
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 system effectively reduces the amount of wash medium required and operator attention, achieving lactose crystals with less than 0.3% ash and 0.1% protein, meeting commercial standards and producing a white product by efficiently separating lactose from impurities and riboflavin.
Implementation Method 1
separating lactose crystals from the mother liquor, purifying the crystals through washing with water, and drying the washed crystals
Implementation Method 2
Lactose crystals have a tendency to tenaciously adsorb riboflavin, which is present in milk products. Lactose crystals may exhibit a yellow color due to the presence of adsorbed riboflavin. This riboflavin may be removed from the crystal surface to produce white lactose.
Data Source
AI summary
An example method for refining lactose may include washing lactose crystals in a lactose stream in an upstream wash stream including an upstream recirculating wash medium. Washed lactose crystals may be sieved from the upstream recirculating wash medium. The upstream recirculating wash medium may be recirculated back to the upstream wash stream. The washed lactose crystals may be discharged to a downstream wash stream comprising a downstream recirculating wash medium. An example system may include a plurality of refining stages. At least one refining stage may include a washing tank including a lactose crystal inlet and a crystal slurry outlet. The refining stage may include a pump to recirculate a wash stream from the crystal slurry outlet back to the washing tank at a predetermined flow rate. The refining stage includes a screen to separate washed lactose crystals from the wash stream.