Polymer Pellet Crystallizer Temperature Control via Solid Additives

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Solution Overview

Problem

The existing methods for crystallizing polyester pellets are energy-intensive and costly due to the need for extensive heating, cooling, and reheating processes, which result in a significant energy penalty and high equipment costs for maintaining large and expensive crystallizers.

Innovation Solution

A method and system that introduces polymeric pellets into a crystallizer where they are contacted with solid additives to adjust their temperature for partial crystallization, maintaining the average pellet temperature below the melting point, and utilizing a conveyor to agitate and transport the pellets to prevent clumping, thereby reducing the length and cost of the crystallizer equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pellets are cooled to 20°C to 30°C to avoid sintering during storage, then sintering is prevented, but significant energy is consumed for cooling and subsequent reheating

Engineering Contradiction:

Improveprevention of sinteringVSAvoidenergy consumption for cooling and reheating

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The pellets are pre-cooled during the extrusion process itself, before storage and processing. The extrusion die surface is cooled to remove heat from the pellets as they are formed, so that when pellets are stored they already have reduced heat content and do not require additional cooling to prevent sintering

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The extrusion process itself provides the cooling function through the die surface, eliminating the need for separate cooling equipment. The system uses its own operational components (the die) to perform the cooling function that would otherwise require dedicated cooling infrastructure

Inventive Principle:

Principle #25Self-service

2Reliability

If large crystallizers are used for crystallization, then crystallization can be achieved, but equipment cost and length increase significantly

Engineering Contradiction:

Improvecrystallization capabilityVSAvoidcrystallizer length

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

Pellets are pre-cooled during extrusion before entering the crystallizer, so they enter at a lower temperature that is closer to the crystallization temperature range. This preliminary cooling reduces the temperature differential that needs to be managed in the crystallizer, allowing for a shorter equipment length

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the temperature parameter of the pellets before they enter the crystallizer by cooling them during extrusion. This parameter change allows the crystallization process to occur more efficiently in a shorter residence time and shorter equipment length

Inventive Principle:

Principle #35Parameter changes

3Reliability

If pellets are reheated to crystallization temperature after cooling, then crystallization can proceed, but energy penalty increases

Engineering Contradiction:

ImprovecrystallizationVSAvoidenergy penalty from heating cycle

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The pellets are pre-cooled during extrusion to a temperature that is already close to the optimal crystallization temperature range. This eliminates or reduces the need for subsequent reheating, as the pellets can be directly crystallized or require minimal temperature adjustment

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heat that would normally be wasted during cooling is instead utilized to bring the pellets to an optimal temperature for crystallization. The cooling process during extrusion is transformed from a separate energy-consuming step into a beneficial pre-conditioning step that prepares pellets for efficient crystallization

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 allows for efficient crystallization of polymeric pellets with reduced energy consumption and equipment costs, minimizing the length of the crystallizer and maintaining the pellets' temperature for effective crystallization without causing melting or sticking, thus optimizing the crystallization process.

Implementation Method 1

the plurality of solid additives adjusts the temperature of the pellets by having a temperature sufficient to allow at least partial crystallization of the plurality of polymeric pellets while maintaining the average pellet temperature below the melting temperature

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

allow at least partial crystallization of the plurality of polymeric pellets

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS7501482B2Crystallizer temperature control via solid additive control

Publication Date: 2009.03.10 ALPEK POLYESTER SA DE CV

AI summary

A method of crystallizing polymeric pellets includes a step in which a plurality of polymeric pellets are introduced into a crystallizer. While within the crystallizer, the plurality of pellets is contacted with a plurality of solid additives for the purpose of adjusting the average pellet temperature. The plurality of solid additives adjusts the temperature of the pellets by having a temperature sufficient to allow at least partial crystallization of the plurality of polymeric pellets while maintaining the average pellet temperature below the melting temperature. Finally, the plurality of polymer pellets is removed from the outlet of the crystallizer.