太阳能电池板热解特性及其金属资源回收

Thermal decomposition characteristics of solar panels and their metal resource recovery

  • 摘要: 在全球推动碳中和的背景下,太阳能电池作为一种清洁、可再生且无污染的发电方式,近年来取得了显著的发展。晶硅太阳能电池技术相对成熟,已成为市场主流,并广泛应用于各类能源系统中。然而,晶硅太阳能电池的使用寿命通常不超过30 a,随着大量电池的报废,不及时且妥善的回收可能导致严重的环境问题,如重金属污染和宝贵资源的浪费。现有的太阳能电池板回收方法主要包括化学药剂法、机械破碎法及热处理法,而热解法凭借其高效的回收能力,已在工业界得到广泛应用。通过试验研究,详细探讨了不同热解条件对太阳能电池板回收效果的影响,重点考察了热解温度(400~600 ℃)、升温速率(5~15 ℃/min)以及热解气氛(N2、CO2、H2)的变化对电池板回收效率的影响。研究表明:5 ℃/min的升温速率、500 ℃的热解温度以及在CO2气氛下的热解条件最有利于获得完整的电池片。此外,随着热解温度和升温速率的增加,气体产物的产量也显著增加,尤其是在CO2气氛下。此外,温度的升高显著增加了CH4和C2H4的生成比例;在H2气氛下,C2H6、C2H4和C3H6的生成量更多。较高的温度和升温速率有助于提高铝的回收效率,但高温可能会降低铜的回收率。最后,对太阳能电池板回收的经济效益进行了评估。分析结果显示,银元素的回收对整个经济效益的贡献超过50%。这一研究为未来更高效、更环保的太阳能电池板回收技术提供了重要的参考依据。

     

    Abstract: Against the backdrop of global efforts to achieve carbon neutrality, solar cells are recognized as a clean, renewable, and pollution-free power generation methodd, with significant advancements made in recent years. Crystalline silicon solar cell technology, being relatively mature, has become the mainstream in the market and is widely applied in various energy systems. However, the lifespan of crystalline silicon solar cells typically does not exceed 30 years. Without timely and proper recycling, the disposal of a large number of cells could lead to severe environmental issues, such as heavy metal pollution and the waste of valuable resources. Current methods for recycling solar panels mainly include chemical treatment, mechanical crushing, and thermal processing. Among these, pyrolysis has gained widespread industrial application due to its efficient recycling capabilities. Effects of different pyrolysis conditions on the recycling performance of solar panels are investigated experimentally, with a focus on the impact of pyrolysis temperature (400-600 ℃), heating rate (5-15 ℃/min), and pyrolysis atmosphere (N2, CO2, H2) on recycling efficiency. The results indicate that a heating rate of 5 ℃/min, a pyrolysis temperature of 500 ℃, and a CO2 atmosphere are the most favorable conditions for obtaining intact solar cells. Additionally, the yield of gaseous products significantly increases with higher pyrolysis temperatures and heating rates, particularly in a CO2 atmosphere. Moreover, the increase in temperature notably enhances the production ratio of CH4 and C2H4; in a H2 atmosphere, the generation of C2H6, C2H4, and C3H6 is more pronounced. Higher temperatures and heating rates are found to improve the recovery efficiency, whereas excessive temperatures may reduce copper recovery rates. Finally, the economic benefits of solar panel recycling were assessed, revealing that the recovery of silver contributes over 50% to the overall economic return. This research provides essential insights for the development of more efficient and environmentally friendly solar panel recycling technologies in the future.

     

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