Vertical Multistage Reactor for Polyamidation
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Solution Overview
Problem
Conventional methods for producing high molecular weight polyamides in vertical multistage reactors face challenges such as degradation, gel build-up, and the need for mechanical agitation, which complicates reactor design, increases costs, and limits production output due to the requirement for large and complex agitators.
Innovation Solution
A continuous process involving counter-current flow of molten dicarboxylic acid and diamine in a vertical multistage reactor, where the viscosity of the polyamide is controlled by adjusting the chemical equilibrium, pressure, or steam injection, eliminating the need for mechanical agitation and allowing for larger reactor sizes and improved mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If mechanical agitation is used to ensure homogeneous mixing in vertical multistage reactors, then mixing efficiency is improved, but device complexity and capital expenditure increase due to the need for large and complex agitators
Solution Approach 1:
The patent replaces mechanical agitation systems with a counter-current flow system where molten diacid and diamine streams flow in opposite directions through the reactor stages. This substitution eliminates the need for complex mechanical agitators while achieving homogeneous mixing through the controlled counter-current flow of reactants, thereby reducing device complexity and capital expenditure.
Solution Approach 2:
The patent employs fluid flow dynamics (hydraulics) to achieve mixing and heat transfer without mechanical agitation. The counter-current flow of molten materials creates natural mixing patterns and heat exchange mechanisms that eliminate the need for mechanical agitators, reducing reactor design complexity while maintaining mixing efficiency.
2Productivity
If mechanical agitation is used to prevent gel build-up, then reaction efficiency is improved, but productivity is limited due to the size constraints of agitators in large reactors
Solution Approach 1:
The patent eliminates mechanical agitators entirely by using counter-current flow to prevent gel build-up and ensure reaction efficiency. This allows for larger reactor sizes and higher production outputs without being constrained by agitator size limitations, thereby improving productivity while reducing device complexity.
Solution Approach 2:
The patent divides the reactor into multiple vertical stages with counter-current flow paths. This segmentation allows the reactants to mix and react efficiently in each stage while preventing gel build-up, enabling larger overall reactor capacity and higher productivity without requiring proportionally larger mechanical agitators.
3Productivity
If high temperatures are used to retain components in melt form, then reaction efficiency is improved, but harmful factors increase due to degradation and discoloration
Solution Approach 1:
The patent employs continuous counter-current flow of reactants through the reactor stages, allowing the reaction to proceed efficiently at controlled temperatures without the need for high temperatures to maintain melt form. The continuous flow ensures consistent heat transfer and reaction progression, reducing thermal degradation and discoloration while maintaining high reaction efficiency and productivity.
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 simplifies reactor design, reduces energy requirements, increases production output, and minimizes impurities and colorants, while reducing capital expenditure and improving heat transfer and reliability.
Implementation Method 1
flowing a stream A comprising a molten dicarboxylic acid, or a molten dicarboxylic acid-rich mixture comprising a dicarboxylic acid and a diamine, through a first stage and at least one more reaction stage of a vertical multistage reactor, wherein the first stage is at the top of the reactor; counter-currently flowing a stream B comprising a diamine as either a vapour or a diamine-rich liquid through at least one of the stages below the first reaction stage of said vertical multistage reactor
Implementation Method 2
the reaction of a dicarboxylic acid with a diamine via counter-current flow in a vertical multistage reactor
Implementation Method 3
the viscosity of said liquid phase material P is controlled by directly controlling the chemical equilibrium of the polyamidation reaction in the reactor or by controlling stream B so that the amounts of diamine and dicarboxylic acid introduced into the reactor during the process are stoichiometrically imbalanced
Data Source
Figure 1
Figure 2a~2b
Figure 3a
AI summary
A continuous process for the manufacture of a polyamide, the process comprising the steps of: (i)flowing a stream A comprising a moltendicarboxylic acid, or a molten dicarboxylic acid-rich mixture comprising a dicarboxylic acid and a diamine, through a first stage and at least one more reaction stage of a vertical multistage reactor, wherein the first stage is at the top of the reactor; (ii)counter-currently flowing a stream B comprising a diamine as either a vapour or a diamine-rich liquid through at least one of the stages below the first reaction stage of said vertical multistage reactor; (iii)accumulating a liquid phase material P comprising polyamide at and/or below the final stage of said reactor; wherein said reactor is equipped with internal features suitable for effecting contact between counter-currently flowing streams A and B; and wherein the process further comprises controlling the viscosity of said liquid phase material P by directly controlling the chemical equilibrium of the polyamidation reactionor by controlling stream B so that the amounts of diamine and dicarboxylic acid introduced intothe reactorduring the processare stoichiometrically imbalanced. The invention further provides a vertical multistage reactor configured to implement said process.