Acetic Acid Reactor Feed via Pump-Around Loop
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Solution Overview
Problem
The capacity of existing systems for producing acetic acid is limited by the amount of reactants that can be fed to the reactor, as increasing the feed requires upgrading high-pressure pumps, which is economically unattractive and inefficient.
Innovation Solution
The process involves feeding a portion of the reactant, such as methanol, methyl acetate, or dimethyl ether, to a pump-around loop, allowing increased reactant availability in the carbonylation reactor without the need for pump upgrades, by introducing it upstream of the reactor recycle pumps or directly to the liquid recycle stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feed amount of reactants to the reactor is increased to enhance acetic acid production, then productivity increases, but the existing high-pressure pumps cannot handle the increased throughput, requiring expensive pump upgrades
Solution Approach 1:
The patent divides the single reactor feed system into multiple feed points: the original reactor feed line and an additional pump-around loop feed line. This segmentation allows reactants to be introduced at different locations in the process, enabling increased total feed rate without overloading the original high-pressure pump system.
Solution Approach 2:
The pump-around loop serves as an intermediary pathway that bypasses the limitation of the original high-pressure pump. By introducing reactants through this intermediate loop that recycles liquid from the reactor outlet back to the reactor inlet, the system can handle increased throughput without requiring upgrades to the main feed pumps.
2Productivity
If high-pressure pumps are upgraded to handle increased reactant feed, then productivity can increase, but the cost of upgrading high-pressure pump systems is economically unattractive
Solution Approach 1:
Instead of investing in expensive, durable high-pressure pump upgrades, the patent employs a lower-cost pump-around loop system that uses existing process streams. This approach substitutes costly capital equipment investment with a more economical process modification that achieves the same productivity goal.
Solution Approach 2:
The patent changes the operational parameters of the existing pump system by adding a parallel feed pathway through the pump-around loop. This allows the system to operate at higher total throughput without changing the fundamental high-pressure pump equipment, avoiding the need for expensive upgrades while achieving increased productivity.
3Productivity
If more reactants are fed to the reactor, then acetic acid production rate increases, but the concentration of impurities such as acetaldehyde and propionic acid also increases
Solution Approach 1:
The pump-around loop introduces reactants at a point where they can partially react in the recycle stream before entering the main reactor. This preliminary reaction reduces the burden on the main reactor and decreases the formation of unwanted condensation byproducts like acetaldehyde and propionic acid that occur when excess reactants accumulate.
Solution Approach 2:
The pump-around loop creates a feedback mechanism where liquid recycles from the reactor outlet back through the feed point. This continuous circulation allows for better control of reactant concentrations and reaction conditions, preventing the accumulation of impurities that would otherwise occur with simply increasing the feed rate to the reactor.
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 enhances acetic acid production by increasing the reactant concentration in the reactor, reduces impurities like acetaldehyde and propionic acid, and improves separation and purification efficiencies, thereby increasing the yield of high-purity acetic acid.
Implementation Method 1
The catalysis contains rhodium and/or iridium and a halogen promoter, typically methyl iodide. The reaction is conducted by continuously bubbling carbon monoxide through a liquid reaction medium in which the catalyst is dissolved.
Implementation Method 2
The reaction is conducted by continuously bubbling carbon monoxide through a liquid reaction medium in which the catalyst is dissolved.
Implementation Method 3
feeding a portion of the at least one reactant to the pump-around loop
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
This invention relates to processes for producing acetic acid from carbon monoxide and, in particular, to improved processes, wherein at least one reactant is fed upstream of a reactor recycle pump and/or to a pump-around loop.