Acetic Acid Production Process for Formic Acid Reduction
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Solution Overview
Problem
The existing methods for producing acetic acid through the carbonylation of methanol result in the formation of formic acid as a by-product, which reduces the purity of acetic acid and destabilizes the catalyst when water concentration is controlled to minimize formic acid levels.
Innovation Solution
Maintaining low hydrogen partial pressure, low carbon dioxide partial pressure, and high temperature conditions in the reaction and distillation steps, with recycling of formic acid-rich fractions to decompose formic acid, effectively suppressing its formation and concentration in the product acetic acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water concentration in the reaction medium is decreased to lower formic acid concentration, then formic acid formation is suppressed, but catalyst stability deteriorates
Solution Approach 1:
The patent extracts and removes formic acid from the reaction system by controlling distillation conditions. By adjusting the distillation temperature and pressure to maintain specific hydrogen and carbon dioxide partial pressures, formic acid is selectively removed from the reaction medium without requiring extreme water concentration control, thus preserving catalyst stability while reducing formic acid concentration in the final product
Solution Approach 2:
The patent changes operational parameters during the distillation process, specifically controlling temperature, pressure, and gas partial pressures. By dynamically adjusting these parameters, the system achieves optimal formic acid removal at different stages of distillation, resolving the contradiction between formic acid reduction and catalyst protection
2Manufacturing precision
If multiple distillation columns are used to purify acetic acid, then product purity is improved, but device complexity increases
Solution Approach 1:
The patent designs distillation columns that perform multiple functions: the first distillation column simultaneously removes lower boiling point components and controls formic acid concentration, while also serving as a dehydration step. This multi-functionality reduces the total number of columns needed compared to conventional sequential purification trains, achieving high purity with simplified 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 efficiently lowers the formic acid concentration in the acetic acid product, stabilizes the catalyst, and improves the overall purity of acetic acid by decomposing formic acid under specific operating conditions.
Implementation Method 1
formic acid can be decomposed by recycling a process solution containing the formic acid to a reaction vessel, an evaporator, or a distillation column and maintaining a low hydrogen partial pressure, a low carbon dioxide partial pressure, and a high temperature
Implementation Method 2
The reaction mixture is evaporated in an evaporator, and the vapor phase is purified in a lower boiling point component removal column
Implementation Method 3
the vapor phase is purified in a lower boiling point component removal column and subsequently in a dehydration column so that product acetic acid is prepared
Data Source
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AI summary
It is intended to provide a method capable of lowering a formic acid concentration in product acetic acid by a simple approach. The method for producing acetic acid according to the present invention comprises at least one step selected from a step that satisfies the following operating conditions (i) and a step that satisfies the following operating conditions (ii) in an acetic acid production process: (i) operating conditions involving a hydrogen partial pressure of less than 500 kPa (absolute pressure), a carbon dioxide partial pressure of less than 70 kPa (absolute pressure), and an operating temperature of more than 175°C; and (ii) operating conditions involving a hydrogen partial pressure of not more than 5 kPa (absolute pressure), a carbon dioxide partial pressure of less than 20 kPa (absolute pressure), and an operating temperature of more than 100°C.