Acetic Acid Distillation Column Material and Temperature Control
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Solution Overview
Problem
The existing methods for producing acetic acid through the carbonylation of methanol fail to sufficiently extend the life of silver-substituted ion exchange resins used for removing organic iodine compounds, leading to increased metal ion concentrations and deterioration in the quality of the product acetic acid due to corrosion and ion exchange issues.
Innovation Solution
The method involves using a nickel base alloy or zirconium for the dehydration column, controlling metal ion concentrations, and maintaining a column bottom temperature below 175°C to reduce metal ion concentrations in the acetic acid, thereby enhancing the life of the ion exchange resin and improving the quality of the acetic acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional dehydration column material is used, then the process is simpler and cheaper, but metal ion concentrations increase and ion exchange resin life decreases
Solution Approach 1:
The patent applies parameter changes by controlling the column bottom temperature to 175°C or lower and managing metal ion concentrations in the charging mixture. This temperature control prevents excessive corrosion and metal ion release, thereby extending ion exchange resin life while maintaining low metal ion concentrations in the product acetic acid.
Solution Approach 2:
The patent employs composite material strategy by selecting specific dehydration column materials (nickel base alloy or zirconium) that resist corrosion and minimize metal ion release. These materials form a composite system with the ion exchange resin, where the column material protects against corrosion and the resin removes organic iodine compounds, achieving both low metal ion concentrations and extended resin life.
2Productivity
If column bottom temperature is increased, then distillation efficiency improves, but metal ion concentrations increase and resin life decreases
Solution Approach 1:
The patent optimizes the column bottom temperature parameter to 175°C or lower, finding the optimal balance between distillation efficiency and metal ion release. This parameter control ensures sufficient distillation performance while preventing excessive corrosion that would release metal ions and degrade the ion exchange resin.
3Quantity of substance
If metal ion concentrations are reduced, then ion exchange resin life is extended, but distillation process becomes more challenging
Solution Approach 1:
The patent manages metal ion concentrations through controlled parameter changes in the distillation process, specifically maintaining column bottom temperature at 175°C or lower and controlling the composition of the charging mixture. This approach achieves low metal ion concentrations without requiring overly complex process modifications.
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 significantly extends the life of the silver-substituted ion exchange resin and reduces metal ion concentrations in the acetic acid, resulting in high-quality acetic acid suitable for electronic material applications.
Implementation Method 1
the metal ion concentrations in the acetic acid fed into the IER in a subsequent adsorptive removal step can be controlled to a low level
Implementation Method 2
an adsorptive removal step of treating the purified acetic acid stream obtained in the acetic acid distillation step with an ion exchange resin
Implementation Method 3
a distillation step of carrying out the purification of the acetic acid stream under conditions of a column bottom temperature of the distillation column of less than 175° C.
Implementation Method 4
the organic iodine compound concentration in the acetic acid has been reduced to as low as possible by using a cation exchange resin substituted with silver ions
Data Source
AI summary
A method for producing acetic acid can improve the life of a silver-substituted ion exchange resin for removing organic iodine compounds in acetic acid. In a carbonylation process of a methanol method, an acetic acid distillation step has at least one distillation step of carrying out the purification of an acetic acid stream under conditions of a column bottom temperature of a distillation column of less than 175° C., a nickel base alloy or zirconium is used as a material of the distillation column in the distillation step, and as metal ion concentrations in a charging mixture of the distillation column in the distillation step, an iron ion concentration is less than 10,000 ppb by mass, a chromium ion concentration is less than 5,000 ppb by mass, a nickel ion concentration is less than 3,000 ppb by mass, and a molybdenum ion concentration is less than 2,000 ppb by mass.