Impact Reactor Cooling Medium for Composite Material Comminution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing impact reactors often heat plastic materials due to high mechanical stress during comminution, leading to undesirable changes in material properties, particularly when processing temperature-sensitive materials like polyethylene terephthalate (PET) in beverage packaging, which limits their recyclability.
Innovation Solution
An impact reactor design that incorporates a cylindrical shell with a rotor and additional filling openings for a cooling medium, such as water, which is introduced alongside the composite material to absorb energy and prevent overheating, along with optional additives for enhanced cleaning and separation, and a classification device for continuous or batchwise discharge of comminuted components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high mechanical stress is applied during comminution to effectively crush composite material, then comminution efficiency is improved, but the plastic material heats up causing undesirable changes in material properties
Solution Approach 1:
A cooling medium (water or liquid nitrogen) is introduced as an intermediary substance between the rotor and the plastic material. The cooling medium absorbs the mechanical energy and heat generated during comminution, preventing the plastic material from overheating while still allowing effective crushing to occur.
Solution Approach 2:
The physical state and temperature of the cooling medium are utilized to counteract the heat generation during comminution. By controlling the temperature parameter of the cooling medium (using cold water or liquid nitrogen), the process maintains low plastic material temperature despite high mechanical stress.
2Temperature
If cooling medium is introduced into the impact reactor to prevent overheating, then plastic material temperature is controlled, but the device complexity increases
Solution Approach 1:
The cooling medium serves multiple functions simultaneously: it cools the plastic material to prevent overheating, absorbs mechanical energy to reduce wear on the rotor, and can facilitate separation of comminuted material. This multi-functionality justifies the additional structural elements required.
Solution Approach 2:
The cooling medium (particularly water) provides self-cleaning effects by washing away contaminants and comminuted material from the rotor surface, reducing maintenance requirements and allowing the system to service itself to some extent.
3Temperature
If water is used as cooling medium to absorb energy and prevent overheating, then plastic material temperature is controlled, but the energy input required increases
Solution Approach 1:
The mechanical energy that would otherwise be converted to harmful heat is instead transferred to the water, which absorbs it through its high specific heat capacity. The water converts the harmful thermal energy into internal energy, preventing plastic material overheating while utilizing the same energy input.
Solution Approach 2:
When liquid nitrogen is used as the cooling medium, it undergoes phase transition from liquid to gas, absorbing large amounts of energy in the process. This phase change efficiently removes heat from the plastic material without requiring excessive continuous energy 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 method effectively and gently comminutes composite materials like PET-containing beverage packaging, preventing overheating and allowing for high-quality recycling by mixing the cooling medium with the material to absorb energy, while also facilitating the separation and removal of contaminants, resulting in a cleaned and separated output.
Implementation Method 1
Because water has a very high energy absorption capacity, heating of the composite material can be effectively avoided
Implementation Method 2
The water dampens the Momentum transfer from the rotor to the composite material, but transfers simultaneously the recorded impulse on the composite material
Implementation Method 3
The objects are crushed by impact stress with a high pulse transmission using rotating impact elements
Data Source
AI summary
The invention relates to an impact reactor (1) for comminuting composite material, comprising a cylindrical shell (2), in which a rotor (3) is arranged, a filling opening (9) for filling the composite material, and a removal opening (8) for discharging the comminuted composite material, wherein at least one additional filling opening (10) for a cooling medium is provided.