Power Battery Vacuum Cracking With Staged Pyrolysis
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Solution Overview
Problem
Traditional high-temperature treatment methods for recycling power batteries face issues such as dioxin production in aerobic pyrolysis, tar and coke generation in anaerobic cracking, leading to secondary pollution, acid and alkali consumption, and difficulties in wastewater treatment, which hinder effective recycling and resource recovery.
Innovation Solution
A vacuum cracking method that combines battery cracking and pyrolysis, where waste power batteries are preheated, cracked under an inert atmosphere, and then pyrolyzed in an aerobic environment, allowing for the recovery of heat and avoidance of secondary pollution, with cracked gas used as fuel for pyrolysis, and the apparatus includes sequential sealing units for material and gas isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional aerobic pyrolysis method is used, then battery treatment is achieved, but dioxin is produced causing secondary pollution
Solution Approach 1:
The treatment process is divided into two separate stages: first anaerobic cracking to decompose organic substances without producing dioxin, then aerobic pyrolysis to burn remaining materials. This segmentation prevents the formation of harmful dioxins by avoiding direct aerobic decomposition of chlorinated compounds.
Solution Approach 2:
Anaerobic cracking is performed as a preliminary step before aerobic pyrolysis. This preliminary action removes organic substances that would otherwise react with oxygen during pyrolysis to form dioxins, thereby preventing secondary pollution.
2Ease of manufacture
If traditional anaerobic cracking method is used, then battery cracking is achieved, but tar and cokes are produced affecting subsequent processes
Solution Approach 1:
The process separates cracking and pyrolysis into distinct stages with different atmospheric conditions. Anaerobic cracking breaks down organic materials into gas, liquid, and solid products, followed by aerobic pyrolysis that combusts tar and cokes, converting them into CO2 and H2O.
Solution Approach 2:
The atmospheric parameter (oxygen presence) is changed between stages: anaerobic conditions during cracking to preserve valuable gases, then aerobic conditions during pyrolysis to eliminate tar and cokes. This parameter change resolves the contradiction between cracking efficiency and byproduct formation.
3Ease of manufacture
If traditional high-temperature treatment is used, then battery decomposition is achieved, but heat cannot be recovered making temperature control difficult
Solution Approach 1:
The heat generated during aerobic pyrolysis, which would normally be wasted energy, is captured and used to preheat the feed material entering the cracking unit. This converts the harmful heat loss into a beneficial preheating function, improving energy efficiency and simplifying temperature control.
Solution Approach 2:
The pyrolysis unit and cracking unit are thermally coupled through heat exchange. The high-temperature aerobic pyrolysis process is merged with the lower-temperature anaerobic cracking process via heat recovery, allowing the exothermic pyrolysis to supply heat for the endothermic cracking operation.
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 method effectively decomposes tar and cokes, reduces acid and alkali consumption, simplifies wastewater treatment, and increases the yield of valuable metal recoveries, while avoiding dioxin production and enhancing resource utilization by using cracked gas as fuel.
Implementation Method 1
heated and cracked under an inert atmosphere or vacuum to obtain cracked gas, solid cracked products and non-crackable products
Implementation Method 2
the crushed material is transported to a cracking unit through a first sealing unit for preheating, then heated and cracked
Implementation Method 3
the solid cracked products and non-crackable products are transported to a pyrolysis unit through a second sealing unit for pyrolysis in an aerobic atmosphere to obtain pyrolysis gas and non-pyrolysis products
Implementation Method 4
pyrolysis in an aerobic atmosphere to obtain pyrolysis gas mainly composed of carbon dioxide and water vapor
Implementation Method 5
the cracked gas is used as a fuel for pyrolysis in the step (3)
Data Source
AI summary
A vacuum cracking method and a cracking apparatus for a power battery are disclosed. The vacuum cracking method includes the following steps that: waste power batteries are fed from a feed hopper and then enter a rolling unit for rolling treatment to obtain a crushed material; the crushed material is transported to a cracking unit for preheating, then heated and cracked under an inert atmosphere or vacuum to obtain cracked gas, solid cracked products and non-crackable products; and the solid cracked products and the non-crackable products are transported to a pyrolysis unit for pyrolysis at an aerobic atmosphere to obtain pyrolysis gas and non-pyrolysis products.