Road Rubble Processing via Low-Temperature Oxidation
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Solution Overview
Problem
Existing methods for processing road demolition materials containing pitch are costly and inefficient, requiring high temperatures that damage aggregate mechanical properties and generate toxic residues, while also necessitating catalytic denitrification and external energy sources.
Innovation Solution
A method involving combustion of road demolition material at temperatures not exceeding 600°C with oxidation air, followed by post-combustion and energy recovery through ORC processes, which maintains aggregate mechanical quality and eliminates the need for denitrification and external energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high temperature combustion (800-900°C) is used to process road debris, then the binder is effectively converted into gas, but the mechanical properties of the aggregate are impaired
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperatures (800-900°C) to a lower range (450-600°C), which is sufficient for binder removal while preserving aggregate mechanical properties. This parameter optimization resolves the contradiction between effective binder conversion and aggregate strength preservation.
2Use of energy by moving object
If pyrolysis process is used to convert binder into gas, then the process can operate without external energy supply, but toxic residues (pyrolysis coke) are left on the aggregate
Solution Approach 1:
The patent introduces oxidizing air into the combustion chamber to enable complete combustion of the binder, converting it fully into gaseous products without leaving toxic carbonaceous residues. This oxidation approach eliminates pyrolysis coke while maintaining energy self-sufficiency through autothermal operation.
3Quantity of substance
If high reaction temperatures are used, then the binder is effectively removed, but catalytic denitrification is required increasing process complexity and cost
Solution Approach 1:
By reducing the combustion temperature to 450-600°C, the patent eliminates the formation of significant nitrogen oxides, thereby removing the requirement for catalytic denitrification systems. This temperature optimization simultaneously achieves effective binder removal and simplifies the overall process design.
4Ease of operation
If stand-alone plant with gas burner is used, then the process is simple to operate, but external energy supply is required and transportation cost increases
Solution Approach 1:
The patent implements autothermal combustion where the binder itself serves as the fuel source, generating sufficient heat to sustain the combustion process without external energy input. The binder acts as both the material to be removed and the energy source, eliminating the need for separate fuel supply systems and reducing operational complexity.
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 reduces costs, preserves aggregate mechanical properties, minimizes toxic residues, and allows for autothermal operation, reducing CO2 emissions and fossil fuel consumption.
Implementation Method 1
burning the road debris material in step b) with the supply of oxidizing air at a temperature not exceeding 600°C
Implementation Method 2
the oxidation air used in the initial combustion and/or in the post-combustion is preheated by the flue gases produced during the combustion of the binder
Implementation Method 3
the volatile components of the binding agent are driven off by simple heating; the resulting gases are partly condensed and partly combusted after leaving the reaction vessel. For this to occur, an oxygen-deficient atmosphere is required within the reaction vessel, so this process can be described as pyrolysis
Data Source
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AI summary
The method involves crushing the road scarification material. The crushed road scarification material is heated to a reaction temperature, with which a binding agent is converted into a gas. The road scarification material is burnt under supply of oxidation air at a temperature, which is not exceeding more than 600 degrees Celsius. An independent claim is also included for an arrangement for processing road scarification material.