Polyamide Reactor Cooling Unit for Viscosity Control
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Solution Overview
Problem
Existing polymerization systems for polyamides face challenges in increasing viscosity without causing thermal damage or polymer degradation, as reducing pressure or increasing temperature in the last reactor stage leads to dislocation, thermal damage, or deposits that result in product discoloration and degradation.
Innovation Solution
A reactor system with a cooling unit between flow tube parts and a separate wall heating system, thermally coupled via a single heat transfer circuit, allows for controlled temperature reduction in the polymer melt, enhancing water evaporation and increasing relative viscosity without further equipment changes, while maintaining product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the temperature in the last reactor stage is increased to separate water from polymer melt, then water separation is improved, but thermal damage and dislocation to the polymer occur
Solution Approach 1:
The patent applies preliminary action by cooling the polymer melt in a heat exchanger before it enters the final reactor stage. This pre-cooling step prepares the melt to undergo more extensive water evaporation at lower temperatures in the final stage, thereby achieving better water separation without causing thermal damage to the polymer.
Solution Approach 2:
The patent changes the temperature parameter profile by introducing a cooling step before the final reaction stage. This parameter change allows the system to achieve water separation at lower temperatures than traditionally possible, avoiding thermal damage while improving water removal efficiency.
2Quantity of substance
If the pressure is reduced significantly below 600 mbar absolute to separate water from polymer melt, then water separation is improved, but deposits form on walls causing polymer degradation and discoloration
Solution Approach 1:
The patent applies preliminary action by cooling the polymer melt before the final reactor stage, which prepares the melt for more efficient water evaporation at moderate pressures. This eliminates the need to reduce pressure significantly below 600 mbar, thereby preventing deposit formation on walls and associated polymer degradation.
Solution Approach 2:
The patent changes the approach by using temperature control rather than extreme pressure reduction to achieve water separation. This parameter change allows water evaporation to occur at moderate pressures, avoiding the harmful effects of low-pressure deposits and discoloration.
3Quantity of substance
If additional reactor stages are added to separate water from polymer melt, then water separation and viscosity increase are improved, but system complexity increases
Solution Approach 1:
The patent merges the cooling function and the final reaction function into a single integrated reactor system. The heat exchanger is incorporated within the reactor structure, allowing water separation through cooling and evaporation to occur in one unit rather than requiring multiple separate reactor stages.
Solution Approach 2:
The patent makes the reactor multi-functional by incorporating a heat exchanger within it, enabling the same device to perform both cooling and the final polymerization reaction. This universal design achieves water separation without requiring additional dedicated reactor stages.
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 increases the relative viscosity of polyamide melts by up to 0.2 viscosity points without altering process parameters in subsequent reactors, preventing thermal damage and polymer degradation, thus maintaining high product quality.
Implementation Method 1
the reactor has a cooling unit between the first flow tube part and the second flow tube part... This allows the temperature of the polymer melt at the outlet of the reactor for the prepolymerization to be reduced
Implementation Method 2
a heating unit... the temperature of the polymer melt is set to 240 to 270 ° C, in particular 250 to 265 ° C, by means of a heating unit (2)
Implementation Method 3
a first flow tube part (3) which is coupled to a separate wall heating to avoid heat loss
Implementation Method 4
This shifts the reaction weight so that the proportion of evaporable water in the polymer melt is increased. After reaching chemical equilibrium at a lower temperature... greater water evaporation can be achieved
Data Source
Figure 1
AI summary
This utility new type relates to one used for a polymerization polyamide and a copolymer of reactor, comprising adding inlet area of educt used for (1), heater (2), a single wall heating device of a first flow pipeline part (3), a second flow pipeline has a separate part of a heating device (5), and used for pre-polymer of discharge pipe (7), a reactor in a first flow pipeline part (3) and said second flow pipeline part (5) is provided with a cooler (4). Through according to reactor of this utility new type and according to method of this utility new type a preparation of high viscosity polyamide, the polyamide to a a further strengthening of the polymer and to a high product quality is suitable for a different application field.