Methionine Recrystallization Additive and Temperature Control
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Solution Overview
Problem
Existing processes for producing D,L-methionine result in poorly filterable, porous particles with low bulk density, requiring high energy for washing and drying, and are often carried out in batch or semicontinuous modes, which are not economically feasible on an industrial scale.
Innovation Solution
A continuous process involving the recrystallization of crude methionine using a polyethoxylated sorbitan stearate as a crystallization additive and controlled temperature conditions to produce coarsely granular, readily filterable crystals with high bulk density, while avoiding the accumulation of additives and minimizing energy costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If antifoam is added during crude methionine precipitation to control foaming and improve crystal quality, then methionine is obtained in the form of spherical particles, but the particles become porous requiring large amounts of water for washing and high energy for drying
Solution Approach 1:
The patent changes the temperature parameter during recrystallization, introducing hot methionine solution (90-110°C) into cold suspension (30-50°C) to control crystal growth and achieve non-porous structure with high bulk density, eliminating the need for excessive drying energy
Solution Approach 2:
The patent uses a crystallization additive as an intermediary substance during recrystallization to modify crystal growth behavior, producing dense non-porous particles that require minimal washing and drying energy
2Manufacturing precision
If recrystallization is carried out by adding cold methionine suspension to hot methionine solution, then methionine precipitates out, but the process is not carried out continuously reducing economic feasibility
Solution Approach 1:
The patent inverts the conventional recrystallization procedure by introducing hot methionine solution into cold suspension rather than adding cold suspension to hot solution. This inversion enables continuous processing while maintaining purification quality and achieving high bulk density
3Productivity
If hydroxyethylcellulose is used as crystallization additive in continuous recrystallization with filtrate reuse, then recrystallization can be carried out continuously, but additive accumulates resulting in reduced bulk density
Solution Approach 1:
The patent employs a different crystallization additive system that does not accumulate upon filtrate reuse, allowing continuous processing without the bulk density reduction problem associated with hydroxyethylcellulose accumulation
Solution Approach 2:
The patent optimizes temperature parameters during continuous recrystallization (introducing solution at 90-110°C into suspension at 30-50°C) to maintain high bulk density despite continuous operation and filtrate circulation
4Device complexity
If crude methionine is obtained as platelet-like or flake-like crystals without antifoam, then no additive is needed, but the crystals are poorly filterable
Solution Approach 1:
The patent uses a crystallization additive as an intermediary during recrystallization to modify crystal morphology and improve filterability, transforming poor filterable platelet-like crystals into readily filterable forms with high bulk density
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 methionine crystals with bulk densities above 500 g/l, improving filterability and reducing energy consumption, and can be operated continuously, enhancing economic feasibility.
Implementation Method 1
By introducing carbon dioxide, the basic potassium methioninate solution is neutralized and methionine is precipitated out
Implementation Method 2
The recrystallization takes place by the dropwise addition of a hot methionine solution to a cold methionine suspension, with methionine precipitating out as a result of cooling the hot solution
Implementation Method 3
the recrystallization takes place by introducing a 60 to 110°C-hot methionine solution into a 35 to 80°C-warm methionine suspension
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a process for the preparation of D,L-methionine, in which carbon dioxide is fed to an aqueous potassium methioninate solution obtained by hydrolysis of 5-(2-methylmercaptoethyl)hydantoin, in order to precipitate out crude methionine, which is separated off and purified, where, for the purposes of purification, an aqueous solution of the separated-off crude methionine is prepared and subjected to a recrystallization, characterized in that the solution from which the recrystallization takes place contains potassium ions and also a crystallization additive, where the crystallization additive is a sorbitan fatty acid ester or a mixture of different sorbitan fatty acid esters, and that the recrystallization takes place by introducing a 60 to 110°C-hot methionine solution into a 35 to 80°C-warm methionine suspension, the temperature of which is lower than that of the introduced solution, the temperature of the methionine suspension being maintained between 35 and 80°C during the addition.