Thermoplastic Moulding Compound Recirculation to Prevent Rubber Blockage
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Solution Overview
Problem
Existing processes for producing thermoplastic molding compounds result in high water and rubber content in wastewater, leading to blockages and inefficiencies in downstream plant components, with up to 15% rubber by weight being disposed of, and there is a risk of deposits and blockages in pipelines.
Innovation Solution
A process involving the collection of the liquid phase containing residual rubber in a buffer container for stirring and recirculation back to the precipitation vessel, minimizing rubber removal and reducing the risk of blockages by maintaining product quality and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the liquid phase containing residual rubber is directly recirculated to the precipitation vessel, then rubber loss is minimized, but deposits and blockages occur in pipelines and downstream plant components
Solution Approach 1:
The harmful component (rubber particles) is extracted from the recirculated liquid phase through the disc separator, which separates the rubber-rich phase from the water phase. The separated water phase is then recirculated without rubber particles, preventing blockages while minimizing rubber loss by returning the rubber-rich phase to the precipitation process.
Solution Approach 2:
The disc separator acts as an intermediary device between the recirculation pump and the precipitation vessel. It processes the liquid phase to remove rubber particles before recirculation, serving as a mediator that enables both rubber conservation and pipeline protection simultaneously.
2Reliability
If more dewatering is performed to reduce rubber content in wastewater, then blockage risk is reduced, but rubber particles are lost and product yield decreases
Solution Approach 1:
Instead of discarding rubber particles through excessive dewatering, the system recovers them by separating the rubber-rich phase from the water phase using the disc separator. The recovered rubber-rich phase is returned to the precipitation vessel, maintaining product yield while achieving sufficient dewatering to reduce blockage risk.
Solution Approach 2:
The system changes the approach from removing rubber through dewatering (which causes loss) to separating rubber through phase separation (which enables recovery). This parameter change in the separation mechanism allows rubber to be retained and reused rather than lost with the wastewater.
3Productivity
If direct recirculation of removed water is implemented, then process continuity is maintained, but rubber from the liquid phase causes deposits and blockages in downstream components
Solution Approach 1:
The system maintains continuous recirculation of the liquid phase to the precipitation vessel, ensuring process continuity. The disc separator enables this continuous operation by efficiently separating rubber particles from water in real-time, allowing uninterrupted recirculation without blockages.
Solution Approach 2:
The rubber-containing liquid phase, which would normally be harmful and cause blockages, is converted into a beneficial resource. The rubber-rich phase separated by the disc separator is returned to the precipitation vessel, where the rubber is recovered and reused, turning a harmful waste stream into a valuable material input.
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 effectively reduces the amount of rubber and wastewater, minimizing blockages and maintaining product quality by recirculating the liquid phase containing residual rubber, thereby optimizing the production process.
Implementation Method 1
the buffer container comprising at least one stirrer with which the liquid phase containing residual rubber is stirred to prevent accumulation of the rubber particles still contained in the liquid
Implementation Method 2
feeding a dispersion containing a rubber and also a precipitation solution into a precipitation vessel, to generate an aqueous suspension containing rubber particles
Data Source
AI summary
The invention relates to a method for producing thermoplastic moulding compounds (73), said method comprising: (a) feeding a dispersion (1), that contains a rubber, and a precipitation solution (3) into a precipitation tank (5), an aqueous suspension (9) that contains rubber particles being produced; (b) optionally sintering the rubber particles contained in the aqueous suspension (9) that contains rubber particles to form larger particles; (c) mechanically dewatering the aqueous suspension that contains rubber particles, rubber particles (33) that contain residual moisture and a liquid phase (35) that contains fine-particle rubber being obtained; (d) feeding the rubber particles (33) that contain residual moisture into an extruder (57), the extruder (57) comprising a drawing-in zone (55), a dewatering section (59), at least one feed section (65) for at least one further polymer (67) and/or additives, a mixing section (69), and a discharge zone (71), the liquid phase that contains residual rubber separated in the dewatering section (59) being collected in a buffer tank (63), the buffer tank (63) comprising at least one agitator (75); and returning the liquid phase (77) that contains residual rubber collected in the buffer tank (63) to the precipitation tank (5).