Asphalt Roofing Recycling via Fluid and Solvent Separation
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Solution Overview
Problem
The recycling of asphalt-based roofing materials is challenging due to the difficulty in separating and shredding shingles, which are difficult to handle and require complex equipment modifications, leading to limited recycling options and environmental waste issues.
Innovation Solution
A method involving pressurized fluid streams to mechanically separate aggregate from asphalt-based roofing materials, followed by agitation and pulsing in a separation tank, and subsequent use of solvents to separate fiber and asphalt, utilizing minimal equipment and energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional recycling processes are used to separate aggregate and asphalt from roofing materials, then separation can be achieved, but the process becomes complex and requires multiple process steps
Solution Approach 1:
The recycling process is divided into distinct sequential stages: mechanical size reduction, hydrocyclone separation, and flotation separation. Each stage targets a specific separation function, breaking down the complex task of constituent separation into manageable segments that can be optimized independently while maintaining overall process efficiency
Solution Approach 2:
Water is introduced as an intermediary medium to facilitate separation between hydrophobic aggregate and hydrophilic asphalt. The water-based slurry system enables the use of hydrocyclones and flotation mechanisms, where water acts as the carrier fluid that allows density-based and surface-property-based separation to occur without direct contact between opposing forces
2Productivity
If roofing shingles are shredded on a bulk basis, then material processing can proceed, but the high granular content makes the material difficult to handle, drag, flow, and separate
Solution Approach 1:
Hydraulic principles are applied throughout the process: water is used to create slurry that flows through the system, hydrocyclones use centrifugal force generated by rotating water flow to separate particles, and flotation uses air bubbles rising through water to separate hydrophobic aggregate. This replaces mechanical handling of dry granular material with fluid-based transport and separation, dramatically improving ease of operation
Solution Approach 2:
The material state is changed from dry granular shingles to water-based slurry. This parameter change transforms the handling characteristics, allowing material to flow smoothly through conveyors and processing equipment without the inter-particle friction and clogging problems associated with dry granular materials
3Ease of manufacture
If standard grinding and screening equipment is used for roofing shingle recycling, then basic size reduction can be achieved, but modification is required to reach desired end use products
Solution Approach 1:
Water serves as an intermediary that enables the use of standard hydraulic equipment (hydrocyclones, flotation cells) alongside conventional grinding equipment. This combination allows standard equipment to be used without modification while achieving precise separation of constituents that would be impossible with dry grinding and screening alone
Solution Approach 2:
The process creates a composite approach by combining mechanical size reduction (standard equipment) with hydrodynamic separation (hydrocyclones and flotation). This multi-method approach leverages the strengths of different separation mechanisms to achieve high-purity recovery of aggregate, fiber, and asphalt that cannot be achieved by any single method
4Loss of substance
If roofing shingles are disposed of in landfills, then waste removal is achieved, but the materials take at least 300 years to break down and disposal fees are increasing
Solution Approach 1:
Instead of discarding roofing shingles in landfills, the process recovers all three major constituents (aggregate, fiber, and asphalt) in high purity forms that can be reused in new roofing materials and other applications. This closes the material loop, eliminating the need for long-term landfill disposal and recovering valuable resources that would otherwise be lost
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
High-yield separation of asphalt, fiber, and aggregate constituents, enabling their effective reuse in various applications while reducing landfill waste and energy consumption.
Implementation Method 1
contacting the asphalt-based roofing material with at least one pressurized stream of fluid to mechanically separate the aggregate from the asphalt-based roofing material
Implementation Method 2
agitating or pulsing the separated aggregate, asphalt-based roofing material and fluid in a separation tank
Implementation Method 3
agitating or pulsing the separated aggregate, asphalt-based roofing material and fluid in a separation tank to remove the separated aggregate from the asphalt-based roofing material and fluid by density
Implementation Method 4
a solvent is first added to an asphalt-based material to form a mixture containing asphalt dissolved in solvent
Data Source
AI summary
The present disclosure provides a method, process and system for recycling an asphalt-based roofing material. In particular, the method, process and system are capable of removing and recovering an aggregate product, fiber product and an asphalt product from the asphalt-based roofing material. The aggregate, fiber and asphalt products each may be reused in a variety of applications.