Acrylic Acid Production Process for Reactor Fouling Reduction
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Solution Overview
Problem
The production of acrylic acid from bio-raw materials faces challenges such as fouling in reactors, low selectivity, and the presence of low-boiling point by-products like acetaldehyde and carbon monoxide, which reduce the purity and economic feasibility of the process.
Innovation Solution
A process involving the separation of low- and high-boiling point materials using absorbents, followed by heating and purification steps to enhance energy efficiency and separate by-products, allowing for increased temperature without additional heating calories, thereby improving the yield and purity of acrylic acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gas-phase dehydration reaction using a solid catalyst is used to produce acrylic acid from lactic acid, then the reaction can proceed efficiently, but fouling occurs in the reactor and reaction yield decreases due to lactic acid oligomerization
Solution Approach 1:
The patent applies preliminary action by pre-cooling the reaction mixture to -40°C to -100°C before introducing it to the distillation column. This preliminary cooling step prevents oligomerization reactions from occurring in the reactor by maintaining low temperature conditions, thereby preventing fouling while still allowing efficient acrylic acid production through subsequent separation processes
Solution Approach 2:
The patent changes the temperature parameter from typical reaction temperatures to sub-zero temperatures (-40°C to -100°C) for the cooling step. This parameter change fundamentally alters the reaction kinetics, preventing oligomerization while allowing the dehydration reaction to proceed efficiently when catalyzed, thus resolving the contradiction between productivity and reliability
2Reliability
If bio-raw materials are used as a carbon source to produce acrylic acid, then environmental sustainability is improved, but acrylic acid selectivity is low due to production of by-products such as carbon monoxide, carbon dioxide and acetaldehyde
Solution Approach 1:
The patent applies segmentation by dividing the separation process into multiple stages: first separating low-boiling-point by-products (CO, CO2, acetaldehyde) from high-boiling-point acrylic acid through fractional distillation, then further purifying each fraction. This segmented approach allows efficient separation of desired product from by-products, improving selectivity while maintaining environmental benefits of bio-raw materials
Solution Approach 2:
The patent uses a cooling medium as an intermediary substance to transfer heat from the reaction mixture. The cooling medium circulates through heat exchangers, absorbing heat and enabling precise temperature control during the dehydration reaction and separation processes. This intermediary cooling system allows the process to maintain optimal temperatures for high selectivity while preserving the environmental advantages of using bio-raw materials
3Manufacturing precision
If energy is used to heat the second low-boiling-point material including acetaldehyde in step 3, then separation efficiency in step 4 increases, but energy consumption increases
Solution Approach 1:
The patent merges the heating function with the cooling system by using the cooled second absorbent (which has absorbed heat from the reaction mixture) as the heat source for heating the second low-boiling-point material. This combining of heating and cooling functions into a single integrated thermal management system allows energy recovery and reuse, improving separation efficiency without increasing overall energy consumption
Solution Approach 2:
The patent implements continuous useful action by circulating the second absorbent continuously through the system, where it alternates between absorbing heat from the reaction mixture and providing heat for the second low-boiling-point material. This continuous circulation ensures that the cooling medium continuously performs dual functions, maintaining high separation efficiency while minimizing energy consumption through relentless heat recovery
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 process increases energy efficiency in separation towers, reduces reactor fouling, and enhances the purity and yield of acrylic acid, making it more economically viable and environmentally friendly.
Implementation Method 1
separating a first low-boiling-point material including acetaldehyde (ACHO) and a first high-boiling-point material including acrylic acid (AA) by adding a first absorbent to a reaction product of a bio-raw material and cooling the result
Implementation Method 2
cooling the result
Implementation Method 3
separating a first incompressible material and a second low-boiling-point material including acetaldehyde (ACHO) by adding a second absorbent to the first low-boiling-point material including acetaldehyde (ACHO) and cooling the result
Implementation Method 4
heating the second low-boiling-point material including acetaldehyde (ACHO)
Implementation Method 5
separating the heated second low-boiling-point material including acetaldehyde (ACHO) to acetaldehyde (ACHO) and the second absorbent
Data Source
Figure 1~2
Figure 3
AI summary
The present application relates to a process for producing acrylic acid.