With the booming development of the new energy industry, the demand for recycling waste lithium batteries in the market is experiencing explosive growth. Thermal decomposition technology, as the core means of treating waste lithium batteries, frequently encounters multiple challenges in the tail gas treatment process. This article will deeply analyze the common problems, targeted solutions, and potential safety risks of lithium battery pyrolysis exhaust gas, especially focusing on the upgrading path of heating technology in volatile organic compounds (VOCs) treatment, aiming to provide guidance for the safe and efficient operation of the waste lithium battery recycling industry.

Waste lithium battery pyrolysis exhaust gas: two core issues

1. Pipeline coking: blockage of viscous substances affecting circulation

Polyolefins (PP/PE): Pyrolysis produces long-chain hydrocarbons above C10, which condense into wax like substances and adsorb small molecules to form oily deposits.
SBR (styrene butadiene rubber): Pyrolysis of unsaturated olefin free radical polymerization produces viscous liquid polymer to block pipelines.
PVDF (polyvinylidene fluoride): Residual fluorinated oligomers are mixed with other substances to form a fluorinated viscous mixture that adheres to the pipe wall.
CMC (carboxymethyl cellulose): Pyrolytic carboxylic acid substances adsorb solid particles such as carbon black, forming a “liquid-solid mixed scale layer”.

2. Bag dust removal paste bag: filtration function failure

The viscous condensate blocks the pores of the filter cloth, causing the filtration function of the dust removal system to be lost. The reasons are as follows:

Electrolyte condensation: Pyrolytic carboxylic acids and ketones condense into viscous liquids, which directly adhere to the filter cloth.
SBR polymer: Pyrolytic olefin polymer, such as “glue”, adheres to filter cloth and forms a difficult to remove “particle adhesive” composite scale layer with solid particles.
PVDF pyrolysis: The generated HF combines with water vapor to form hydrofluoric acid, which corrodes the filter cloth and intensifies the adhesion of viscous substances, resulting in filter cloth bag sticking and system paralysis.

Lithium battery pyrolysis exhaust gas solution: precise control throughout the entire process

To solve the problem of thermal decomposition exhaust gas in lithium batteries, efforts need to be made from three aspects: “source process pretreatment”, combined with heating and insulation technology to achieve efficient treatment:

Source control: Temperature rise, viscosity reduction, and burden reduction
Raise the pyrolysis temperature above 500 ℃ to promote further decomposition of incompletely cracked macromolecular intermediates, reduce the generation of viscous substances from the root, and lower the difficulty and pressure of subsequent processing.

Process temperature control: heat tracing, insulation, and anti coking
Using heat tracing technology (such as electric heat tracing) to insulate pipelines, preventing the temperature of pyrolysis products from rapidly dropping from 600 ℃ to below 200 ℃, and avoiding condensation and coking of high boiling point components. At the same time, it is necessary to ensure that the heat tracing equipment has explosion-proof (such as Exd Ⅱ CT6 standard) and corrosion-resistant properties to ensure temperature stability.

Pre treatment purification: dual optimization of debonding filter material
Before the exhaust enters the bag filter, install “de sticking” devices such as high-temperature filters, rapid cooling towers, and defoggers; Choose PTFE and other high-temperature and corrosion-resistant filter materials to reduce the damage of viscous substances to the filter cloth and extend the service life of the equipment.

Advantages of upgrading VOCs treatment heating technology

In the VOCs treatment process, maintaining high temperature stability of exhaust gas is crucial, and electric heat tracing plays an important role in this regard. However, traditional resistance heating methods have problems such as weak electrical performance, low efficiency of pipeline materials at high temperatures, and high energy consumption. After the introduction of electromagnetic heating devices as a replacement in the industry, significant results have been achieved: it avoids the risk of local overheating and short circuits caused by resistance heating, improves insulation and grounding reliability, and reduces fire hazards; Can accurately adapt to high temperature conditions and reduce equipment wear and tear; It can also accurately regulate power, supply energy according to demand, and achieve energy conservation and consumption reduction. When selecting, priority should be given to selecting temperature limiting or constant power electric heat tracing belts to ensure explosion-proof, corrosion-resistant, and overload protection. After installation, regular inspection of the equipment can ensure stable and efficient VOCs treatment.