Retort Chamber Segmentation for Tire Depolymerization
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Solution Overview
Problem
Current thermal depolymerization processes for tires and waste materials face challenges in achieving rapid cycle times, leading to potential explosions and clogging issues due to the mixing of gases and particulates, which hinders efficient processing and product separation.
Innovation Solution
The proposed apparatus includes a retort chamber with multiple temperature zones and a product separation unit, utilizing partial combustion at the bottom to generate heat for depolymerization higher up, with controlled oxygen and water input, and a desulfurization unit to manage sulfur compounds, allowing for quicker cycle times and effective separation of products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cycle time is decreased to around 11 hours, then productivity is improved, but the oxygen introduced through the bottom of the retort chamber and the syngas produced by the depolymerization of the tires mix before reaching the upper third of the retort chamber, posing a risk of explosion
Solution Approach 1:
The retort chamber is divided into distinct zones: a lower combustion zone where oxygen is introduced and tires are partially burned, and an upper depolymerization zone where syngas is produced and removed. This spatial segmentation prevents mixing of oxygen and syngas, eliminating explosion risk while enabling faster cycle times.
Solution Approach 2:
A vacuum line or aspirator is positioned in the upper third of the retort chamber to extract syngas as it is produced, removing it from the system before it can mix with oxygen in the lower zone. This extraction prevents the harmful mixing while maintaining rapid processing.
2Object-generated harmful factors
If a desulfurization unit is used to remove sulfur from products, then sulfur emissions are reduced, but carbon black particulate matter is rapidly removed which can plug up the pipes and lead to the generation of excess pressure in the retort chamber
Solution Approach 1:
A cyclone separator is introduced to extract carbon black particulate matter from the product stream before it enters the desulfurization unit. This preliminary extraction prevents particulates from plugging pipes and causing pressure issues, while allowing the desulfurization unit to effectively remove sulfur emissions.
Solution Approach 2:
The cyclone separator acts as an intermediary device between the retort chamber and the desulfurization unit, filtering out carbon black particulates before they can interfere with the desulfurization process or cause pressure problems in the system.
3Productivity
If thermal depolymerization is carried out at higher temperatures to reduce cycle time, then productivity is improved, but the risk of gas mixing and explosion increases
Solution Approach 1:
The retort chamber is segmented into temperature zones: a lower high-temperature combustion zone and an upper depolymerization zone. This allows high temperatures to be maintained for productivity while spatial separation prevents unsafe gas mixing.
Solution Approach 2:
Syngas is continuously extracted from the upper depolymerization zone via vacuum line or aspirator, removing it from the system before it can mix with oxygen. This extraction maintains process safety even at higher temperatures that reduce cycle time.
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 enables faster processing of waste materials, reduces the risk of explosions, and facilitates the isolation of valuable products like carbon black, olefinic fractions, and fuels, while minimizing environmental sulfur emissions.
Implementation Method 1
The retort chamber in the '876 patent flows oxygen or air into the bottom of the retort chamber, enabling the lower-most tire to burn and generate the heat required to thermally depolymerize the tires overlying the lower-most tire.
Implementation Method 2
The phase separator is connected to an aspiration unit, which enables the depolymerizing device to operate at pressures up to 10 mBar lower than atmospheric pressure.
Data Source
AI summary
An apparatus and process for thermally de-manufacturing tires and other materials. The apparatus is a retort chamber with various zones in which tires are combusted to provide energy for the thermal depolymerization reaction, depolymerization takes place, and products leave the retort chamber. In one embodiment, the process reacts water with iron present in steel-belted tires to produce hydrogen, which helps to break sulfur-sulfur bonds in vulcanized materials. The water also helps control the temperature of the reaction, which allows for control over the types and relative amounts of the various depolymerization products.