Acetic Acid Purification Sampling Device
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Solution Overview
Problem
Acetic acid production processes face challenges in removing impurities such as permanganate reducing compounds and iodine-containing species, which are difficult to control and monitor, leading to contamination and reduced resin efficiency in purification systems.
Innovation Solution
A process involving carbonylation of methanol or dimethyl ether in the presence of a rhodium catalyst, lithium iodide, and methyl iodide, followed by separation and purification using distillation columns and ion exchange resins, including a cationic exchanger and metal-exchanged ion exchange resin, to produce purified acetic acid, with a sampling device allowing for monitoring and control of resin bed exhaustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional purification systems are used to remove impurities from acetic acid, then impurity removal is achieved, but the resin efficiency decreases and resin life is reduced due to contamination
Solution Approach 1:
The patent implements a sampling device that enables preliminary detection of impurities (particularly PRCs and iodine-containing species) before they can contaminate and exhaust the ion exchange resin. By continuously monitoring the feed stream and resin bed outlet, the system can take preventive actions to protect the resin, thereby extending its operational life while maintaining purification efficiency
Solution Approach 2:
The sampling device provides continuous feedback on impurity concentrations at multiple points in the purification system. This feedback mechanism allows for real-time monitoring of resin bed exhaustion and enables process adjustments to optimize resin performance and extend its service life by preventing premature contamination
2Manufacturing precision
If purification processes are implemented to remove impurities, then acetic acid quality is improved, but the complexity of the process increases
Solution Approach 1:
The sampling device is designed with multiple flow paths that serve different functions: one path provides samples for PRC detection while another path provides samples for iodine-containing species detection. This multi-functional sampling system achieves comprehensive impurity monitoring without requiring separate sampling systems for each impurity type, thereby managing process complexity efficiently while maintaining high acetic acid purity
3Manufacturing precision
If multiple distillation columns are used in the primary purification train, then separation efficiency is improved, but the difficulty of detecting and measuring impurities increases
Solution Approach 1:
The sampling device segments the monitoring function by providing separate flow paths for different types of impurity detection. One flow path is dedicated to PRC detection while another is dedicated to iodine-containing species detection. This segmentation allows for specialized detection methods to be applied to each impurity type, making detection and measurement easier despite the complex multi-column distillation process
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 process effectively reduces impurity concentrations, particularly lithium and iodide ions, extending resin life and improving the quality of acetic acid production by enabling continuous monitoring and control of purification systems.
Implementation Method 1
carbonylating at least one member selected from the group consisting of methanol, dimethyl ether, and methyl acetate in the presence of 0.1 to less than 14 wt.% water, a rhodium catalyst, methyl iodide and lithium iodide, to form a reaction medium comprising acetic acid
Implementation Method 2
contacting the crude acetic acid product with a cationic exchanger in the acid form within a first treatment device to produce an intermediate acid product
Implementation Method 3
contacting the intermediate acetic acid product with a metal-exchanged ion exchange resin having acid cation exchange sites within a second treatment device to produce a purified acetic acid
Implementation Method 4
separating the reaction medium into a liquid recycle stream and a vapor product stream; separating the vapor product stream in up to 2 distillation columns
Data Source
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AI summary
The disclosure is directed to a carbonylation process for producing acetic acid which includes separating a vapor product stream from a carbonylation reactor to produce a crude acid product comprising acetic acid comprising lithium cations and contacting the crude acetic acid product with a cationic exchanger in the acid form within a first treatment device to produce an intermediate acid product; and contacting the intermediate acetic acid product with a metal-exchanged ion exchange resin having acid cation exchange sites within a second treatment device to produce a purified acetic acid. Embodiments directed to a treatment device comprising a plurality of sampling ports having a first open flow path and a second flow path comprising a porous element are disclosed.