Lactose Crystallization Yield via Segmented Cooling
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Solution Overview
Problem
Existing lactose production methods result in significant losses due to metastable phases during cooling, leading to small crystal formation and breakage, resulting in 17% and 20% lactose loss, respectively, with the mother liquor containing 35-40% lactose requiring high processing effort.
Innovation Solution
A method involving adjusting the lactose solution temperature between 62-67°C, cooling to 20-30°C, holding for 0.5-5 hours, re-heating to 35-40°C, and then cooling to 10°C to allow crystal growth, reducing lactose loss by solubilizing small crystals and particles, achieving a maximum 20% lactose content in the mother liquor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the lactose solution is cooled continuously from high temperature to low temperature, then the crystallisation process is completed, but small crystal nuclei form during metastable phases and are lost during separation
Solution Approach 1:
The continuous cooling process is segmented into distinct phases: initial cooling to first holding temperature, second cooling to second holding temperature, and final cooling to crystallisation temperature. This segmentation allows control over crystal formation at different stages, preventing premature nucleation and ensuring only mature crystals form and are separable.
Solution Approach 2:
The solution is pre-cooled to first and second holding temperatures before final crystallisation. This preliminary cooling action prepares the solution by removing excess heat and stabilising the lactose concentration, ensuring that when final cooling occurs, crystal formation happens at optimal conditions with minimal nucleation and maximum crystal size.
2Manufacturing precision
If the cooling process is extended to allow crystal growth, then larger crystals are formed, but the process time increases significantly
Solution Approach 1:
The solution is pre-cooled to first holding temperature (e.g., 30-40°C) and held there for a predetermined time (e.g., 1-3 hours) before proceeding to second cooling. This preliminary action allows controlled crystal nucleation and initial growth without requiring extended total cooling time, as the holding period at intermediate temperature accelerates subsequent crystal maturation.
Solution Approach 2:
The cooling process uses periodic holding periods at intermediate temperatures between continuous cooling phases. The solution is cooled to first holding temperature, held for a set time, then cooled to second holding temperature, held again, and finally cooled to crystallisation temperature. This periodic action allows crystal growth to occur at optimal temperatures without requiring continuously extended cooling.
3Manufacturing precision
If stirring is applied in the decanter to improve separation, then separation efficiency increases, but crystal breakage increases and fine particles are formed
Solution Approach 1:
Crystals are formed and matured in the crystallisation tank before being transferred to the decanter for separation. By preparing large, stable crystals in advance during controlled cooling and holding periods, the crystals are less susceptible to breakage during the mechanical separation process, reducing fine particle formation and lactose loss.
4Productivity
If the mother liquor is processed further to reduce residual lactose, then yield improves, but processing effort and cost increase
Solution Approach 1:
The crystallisation process is optimised to achieve maximum crystal formation and mother liquor clarification in the initial cooling and holding phases. By conducting thorough crystallisation and separation in the crystallisation tank before final decanting, the residual lactose in the mother liquor is minimised, reducing or eliminating the need for additional 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
This approach effectively halves lactose loss due to crystal breakage and improves separation efficiency, reducing the lactose content in the mother liquor to a maximum of 20% by weight, enhancing the overall process yield and economy.
Implementation Method 1
the solution is cooled down to about 10° C., and is subsequently held at this temperature for a period of from 12 to 15 h, thus allowing the alpha-lactose crystals to separate
Implementation Method 2
Pure beta-lactose is present above a temperature of 93.5° C. During the cooling process it is quantitatively transformed to alpha lactose
Data Source
AI summary
A method for improving the yield during the production of crystalline alpha lactose is suggested, wherein(a) An aqueous lactose solution is adjusted to a temperature of between about 62 and 67° C.,(b) The solution is cooled down to between about 20 and 30° C.,(c) The solution is held at this temperature for a period of from 0.5 to 5 h,(d) Subsequently, the solution is re-heated to between about 35 and 40° C.,(e) The solution is held at this temperature for a period of from 0.5 to 5 h,(f) Subsequently, the solution is cooled down to about 10° C., and(g) Eventually, the precipitated alpha-lactose crystals are separated from the mother liquor.