Molybdenum Vanadium Catalyst Packing for Acrylic Acid Yield
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Solution Overview
Problem
Existing methods for producing (meth)acrylic acid through gas-phase catalytic oxidation reactions result in insufficient yields due to the formation of carbides, which reduce catalytic activity and increase production costs.
Innovation Solution
A method involving a fixed-bed reactor with a packed layer containing a used and cleaned packing material and a catalyst layer with molybdenum and vanadium, where the catalyst is present at a specific ratio of 0.001-0.15 mass% to suppress carbide formation and enhance yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst is used for gas-phase catalytic oxidation reactions for a certain period, then production continues, but carbides form and catalytic activity decreases
Solution Approach 1:
The patent introduces an inert substance layer as an intermediary between the reaction gas and the catalyst. This inert layer selectively removes impurities from the reaction gas before it reaches the catalyst, preventing carbide formation while allowing the oxidation reaction to proceed. The inert substance acts as a mediator that protects the catalyst from harmful interactions.
Solution Approach 2:
The patent extracts and removes impurities from the reaction gas phase before they can reach the catalyst surface. By using the inert substance layer to trap and remove carbon-containing impurities, the harmful substances are taken out of the reaction system, preventing their deposition on the catalyst as carbides.
2Reliability
If the catalyst is removed and replaced frequently, then catalytic activity is maintained, but production time is lost and costs increase
Solution Approach 1:
The patent applies preliminary action by placing the inert substance layer in advance before the reaction gas reaches the catalyst. This pre-positioned protective layer proactively removes impurities before they can cause carbide formation, preventing catalyst deactivation rather than responding to it after occurrence. This allows the catalyst to maintain activity for extended periods without replacement.
3Productivity
If impurities are allowed to accumulate in the reaction gas, then the process is simple, but carbide formation increases and yield decreases
Solution Approach 1:
The patent merges the inert substance layer with the existing reactor structure, integrating the impurity removal function into the reaction system. Rather than adding a separate complex purification system, the inert layer is incorporated directly into the reactor, combining the reaction and purification functions in a single integrated structure.
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
The method effectively suppresses carbide formation, leading to improved production yields of (meth)acrylic acid and reduced pressure loss, while minimizing cleaning costs and maintaining catalytic activity.
Implementation Method 1
gas-phase catalytic oxidation reactions of (meth)acrolein by using molecular oxygen in a fixed-bed reactor configured to have a packed layer containing a packing material and a catalyst layer formed with a catalyst containing at least molybdenum and vanadium
Implementation Method 2
an inert substance layer is arranged by packing an inert substance between the first catalyst layer and the subsequent catalyst layer so that when a reaction gas from previous reactions passes through the inert layer, impurities contained in the reaction gas are removed to prevent deterioration of catalytic activity
Data Source
Figure 1~2
AI summary
The present invention provides a (meth)acrylic acid-producing method capable of suppressing formation of carbides so that the production yield of (meth)acrylic acid is enhanced. In such a method, (meth)acrylic acid is produced through gas-phase catalytic oxidation reactions of (meth)acrolein by using molecular oxygen in a fixed-bed reactor configured to have a packed layer containing a packing material and a catalyst layer formed with a catalyst containing at least molybdenum and vanadium. The packed layer contains a packing material that has been used at least once for above gas-phase catalytic oxidation reactions, and the catalyst is present in the packed layer at 0.001~0.15 mass% of the total amount of the packing material.