Acrylic Acid Reactor Laminarization to Prevent Autoxidation
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Solution Overview
Problem
Conventional processes for producing acrylic acid from propene via gas-phase oxidation face challenges with autoxidation, leading to undesired complete oxidation and by-product formation, which reduces yield and efficiency.
Innovation Solution
A two-stage process utilizing a tube bundle reactor with a laminarization means in the outflow area to reduce turbulence and autoxidation, featuring a first reactor for acrolein synthesis and a second reactor for its conversion to acrylic acid, with specific catalyst compositions and a cone-shaped laminarization structure to minimize residence time and prevent autoxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas-phase oxidation of propene is carried out in conventional reactors, then acrylic acid can be produced, but autoxidation occurs leading to complete oxidation and by-product formation
Solution Approach 1:
The reactor is divided into multiple tubes arranged in a tube bundle, with each tube containing catalyst layers separated by inert layers. This segmentation prevents autoxidation by isolating reaction zones and controlling gas flow through each tube individually.
Solution Approach 2:
Inert layers are introduced as intermediary barriers between catalyst layers within the tubes. These inert layers prevent direct contact between reactants and catalyst surfaces in uncontrolled ways, thereby preventing autoxidation while still allowing desired oxidation reactions to proceed.
2Ease of operation
If gas flows through the reactor with high turbulence, then mixing is improved, but residence time increases leading to autoxidation
Solution Approach 1:
The system dynamically balances gas flow velocity and residence time by optimizing the number and arrangement of tubes, allowing sufficient mixing while maintaining short enough residence times to prevent autoxidation. The gas flow is continuously moved through the tube bundle with controlled velocity.
Solution Approach 2:
By dividing the gas flow into multiple parallel streams through numerous tubes, the system achieves effective mixing across each tube while the overall residence time remains short. The segmented flow paths prevent prolonged exposure of any single gas parcel to reaction conditions.
3Productivity
If catalyst loading is increased to improve conversion, then reaction efficiency increases, but heat generation increases leading to hot spots and autoxidation
Solution Approach 1:
The catalyst is segmented into multiple layers within each tube, separated by inert layers. This distribution of catalyst loading prevents excessive heat generation in any single location, avoiding hot spots while maintaining overall high conversion efficiency through the cumulative effect of multiple catalyst layers across many tubes.
Solution Approach 2:
Different zones within the tube bundle have optimized catalyst loading and composition tailored to local heat dissipation capabilities. The inert layers create local thermal management zones that prevent hot spot formation while maintaining catalytic activity in adjacent regions.
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 the yield of acrylic acid by reducing autoxidation and preventing damage from explosions, resulting in a more efficient and stable production process.
Implementation Method 1
a laminarization means (8) which causes laminarization of a flow profile of a gas flowing through the outflow area (7)
Implementation Method 2
at least the first reactor (2) is a tube bundle reactor with a plurality of tubes (4) comprising a catalyst which catalyzes the synthesis of acrolein from propene
Implementation Method 3
gas-phase oxidation of propene
Implementation Method 4
the at least one further reactor (3) is a tube bundle reactor with a plurality of tubes (4) comprising a catalyst which catalyzes the conversion of acrolein to acrylic acid
Implementation Method 5
conversion of acrolein to acrylic acid
Data Source
Figure 1
Figure 2~3
AI summary
The present invention relates to a device (1) for producing acrylic acid, comprising a first reactor (2) and at least one other reactor (3), at least the first reactor (2) being a tubular reactor with a plurality of tubes (4) that enclose a catalyst that catalyzes the synthesis of acrolein, with the tubes (4) discharging into a collecting chamber (6), which can be connected for fluid flow through a discharge area (7) to the at least one other reactor (3), with the discharge area (7) comprising means of smoothing flow (8), which bring about a laminar flow profile of a gas flowing through the discharge area (8). The invention also relates to a method for producing acrylic acid, an acrylic acid, a method for producing a hydrophilic polymer, a hydrophilic polymer, a method for producing a water-absorbing hygiene article, chemical products such as fibers, molded objects or films, and to the use of an acrylic acid.