Polyester Granule Post-Condensation Using Residual Heat
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polyester production processes face issues such as thermal stress, high energy and investment costs, thermo-oxidative damage, reduction of molecular weight due to hydrolysis, and viscosity reduction during crystallization, particularly in latent heat crystallization processes.
Innovation Solution
A process combining underwater granulation with thermal treatment using residual heat for post-condensation, where granules are subjected to a gas stream without external heat input, achieving improved water separation and dehumidification, allowing for increased molecular weight and viscosity without adhesion, and enabling direct crystallization and dealdehydization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional solid phase post-condensation is used with additional heat input, then molecular weight can be increased, but thermal damage and energy costs increase
Solution Approach 1:
The patent converts the harmful effect of residual heat (which would normally cause thermal damage) into a beneficial resource by using it as the heat source for post-condensation. The residual heat from granulation is utilized to drive the post-condensation reaction, eliminating the need for additional external heating and thereby preventing thermal damage while increasing molecular weight.
Solution Approach 2:
The patent recovers and reuses the residual heat that would otherwise be wasted or cause thermal damage. By capturing and utilizing this residual heat for the post-condensation process, the system transforms a potential harmful byproduct into a valuable energy resource, achieving molecular weight increase without additional energy input.
2Quantity of substance
If conventional solid phase post-condensation with drying and heating is used, then molecular weight increases, but energy costs and investment costs increase
Solution Approach 1:
The patent converts the harmful effect of residual heat (which would normally cause thermal damage) into a beneficial resource by using it as the heat source for post-condensation. The residual heat from granulation is utilized to drive the post-condensation reaction, eliminating the need for additional external heating and thereby preventing thermal damage while increasing molecular weight.
Solution Approach 2:
The patent recovers and reuses the residual heat that would otherwise be wasted or cause thermal damage. By capturing and utilizing this residual heat for the post-condensation process, the system transforms a potential harmful byproduct into a valuable energy resource, achieving molecular weight increase without additional energy input.
3Ease of operation
If latent heat crystallization is used to avoid sticking, then crystallization is achieved, but viscosity reduction occurs
Solution Approach 1:
The patent implements a continuous process where granulation, drying, and post-condensation occur in sequence without interrupting the heat flow. The residual heat from granulation continuously drives the post-condensation reaction, maintaining elevated temperatures that prevent viscosity reduction while avoiding the sticking problems associated with conventional crystallization methods.
Solution Approach 2:
The patent changes the temperature parameter by utilizing residual heat to maintain higher temperatures during post-condensation compared to conventional crystallization. This parameter change allows the process to achieve both non-sticking granules and increased viscosity by conducting post-condensation at temperatures above the glass transition temperature.
4Stability of the object's composition
If improved water separation and dehumidification is implemented, then viscosity increase is possible with small granules, but process complexity increases
Solution Approach 1:
The patent merges the water separation and dehumidification functions into the existing granulation and drying system. By integrating these functions rather than adding separate complex systems, the process achieves improved water removal capability while minimizing additional device complexity. The residual heat from granulation is simultaneously used for both drying and driving post-condensation.
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 process increases the intrinsic viscosity of polyester granules by up to 0.30 dl/g, reduces thermal damage, lowers energy and investment costs, minimizes material loss, and prevents hydrolysis, while maintaining high-quality granules for further processing.
Implementation Method 1
an increase in the molecular weight is possible without additional heat input and therefore only by using the residual heat and the resulting heat of crystallization
Implementation Method 2
only by using the residual heat and the resulting heat of crystallization
Implementation Method 3
the granules obtained in step a) are subjected directly to stage a) to thermal drying and post-treatment by applying the granules to a gas stream of a gas or gas mixture
Data Source
Figure 1
Figure 2
AI summary
Directly increasing molecular weight of non-adhesive polyester granules using residual heat, during its production, comprises: (a) pressing a polyester raw material as a melt by a nozzle, granulating in a cooling water stream, and separating the granules from the cooling water stream after passing through a cooling water zone; and (b) thermally drying and post-treating a bed of the granules obtained in the step (a) with a gas stream of a gas or a gas mixture. The used granules or the supplied gas or the gas mixture of the gas stream during step (b) are not heated by external energy input. Directly increasing molecular weight of non-adhesive polyester granules using residual heat, during its production, comprises: (a) pressing a polyester raw material as a melt by a nozzle, granulating in a cooling water stream, and separating the granules from the cooling water stream after passing through a cooling water zone; and (b) thermally drying and post-treating a bed of the granules obtained in the step (a) with a gas stream of a gas or a gas mixture. The used granules or the supplied gas or the gas mixture of the gas stream during step (b) are not heated by external energy input. The gas stream is conducted in counter-flow to the conducting direction of the granules into a conditioning device. The average temperature of the granules bed is adjusted to greater than 170[deg] C before it enters the step (b).