Methionine Production Corrosion Inhibition via Impurity Control
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Solution Overview
Problem
The existing process for producing methionine from 3-methylthiopropanal is prone to corrosion of pipes and reaction vessels due to impurities like thiols and hydrogen sulfide, despite the use of corrosion-inhibiting materials, which can lead to equipment damage and process inefficiencies.
Innovation Solution
The process involves reducing the content of thiols and hydrogen sulfide in 3-methylthiopropanal to 500 ppm or less and 60 ppm or less, respectively, before the cyanohydrination step, ensuring that the subsequent hydantoin hydrolysis step is conducted with a basic potassium compound to produce methionine, thereby inhibiting corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If corrosion-inhibiting materials are used for pipes and reaction vessels, then corrosion resistance is improved, but equipment cost increases and corrosion still occurs occasionally
Solution Approach 1:
The invention extracts and removes harmful impurities (thiols and hydrogen sulfide) from the raw material 3-methylthiopropanal before processing. By eliminating these corrosive substances at the source through purification steps, the patent avoids the need for expensive corrosion-inhibiting materials while preventing corrosion in the hydrolysis step.
Solution Approach 2:
The invention performs preliminary purification of the raw material to remove thiols and hydrogen sulfide before the cyanohydrination and hydrolysis steps. This advance removal of corrosive impurities prevents corrosion issues downstream, eliminating the need for special corrosion-resistant equipment materials.
2Ease of manufacture
If thiols and hydrogen sulfide are present in raw material, then production cost is reduced, but corrosion of equipment occurs
Solution Approach 1:
The invention converts the potentially harmful presence of thiols and hydrogen sulfide into a beneficial purification opportunity. By implementing specific purification steps that target and remove these impurities to controlled levels (thiols ≤500 ppm, hydrogen sulfide ≤60 ppm), the patent transforms a cost-saving opportunity into a controlled process that prevents corrosion while maintaining economic efficiency.
Solution Approach 2:
The invention changes the concentration parameters of impurities in the raw material by establishing specific thresholds (thiols at 500 ppm or less, hydrogen sulfide at 60 ppm or less). This parameter control approach balances raw material cost with corrosion prevention, allowing economical raw materials while maintaining equipment safety.
3Productivity
If basic potassium compound is used in hydrolysis step, then methionine production efficiency is improved, but corrosion risk increases with impure raw material
Solution Approach 1:
The invention introduces an intermediary purification step between raw material preparation and the hydrolysis step. This intermediate purification removes corrosive impurities (thiols and hydrogen sulfide) to create a clean feedstock for the basic potassium compound hydrolysis, allowing high productivity without corrosion damage to equipment.
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 prevents corrosion of pipes and reaction vessels during the methionine production process, ensuring the integrity and efficiency of the equipment and maintaining the quality of the methionine product.
Implementation Method 1
3-methylthiopropanal is reacted with hydrogen cyanide in the presence of a base to give 2-hydroxy-4-methylthiobutanenitrile
Implementation Method 2
the 2-hydroxy-4-methylthiobutanenitrile obtained in step (1) is reacted with ammonium carbonate to give 5-(β-methylmercaptoethyl) hydantoin
Implementation Method 3
the 5-(p-methylmercaptoethyl)hydantoin obtained in step (2) is hydrolyzed in the presence of a basic potassium compound to give methionine
Data Source
AI summary
A process for producing methionine, while corrosion of a pipe and a reaction vessel is well inhibited, is provided. The present invention relates to a process for producing methionine comprising the following steps (1) to (3), wherein a content of thiols in 3-methylthiopropanal is 500 ppm or less, based on the propanal, and a content of hydrogen sulfide in 3-methylthiopropanal is 60 ppm or less, based on the propanal; step (1) in which 3-methylthiopropanal is reacted with hydrogen cyanide in the presence of a base to give 2-hydroxy-4-methylthiobutanenitrile; step (2) in which the 2-hydroxy-4-methylthiobutanenitrile obtained in step (1) is reacted with ammonium carbonate to give 5-(β-methylmercaptoethyl)hydantoin; and step (3) in which the 5-(β-methylmercaptoethyl)hydantoin obtained in step (2) is hydrolyzed in the presence of a basic potassium compound to give methionine.