摘要
随着塑料污染问题的日益加剧,废塑料的回收和再利用已成为全球关注的热点。在我国实现碳达峰碳中和目标的背景下,将废塑料转化为高品质的液体燃料,对于实现碳资源循环利用、减少对化石燃料的依赖具有重要意义。综述了废塑料转化为液体燃料的技术,重点分析了催化热解、微波热解和光催化解聚的最新进展。探讨了关键参数对产物选择性的影响,并比较了3种技术在调控液体产物方面的共性与差异:催化热解依赖催化剂特性,微波热解利用热效应和非热效应,光催化解聚则利用光能激活催化剂。这些技术为实现塑料的高值化利用提供了多种途径。同时,还探讨了废塑料定向解聚技术在液体燃料生产中面临的挑战和机遇,并对其未来发展趋势进行了前瞻性展望。
This study evaluates catalytic pyrolysis,microwave pyrolysis,and photocatalytic depolymerization for converting waste plastics into liquid fuels,with an emphasis on the efficiency,selectivity,and scalability.Catalytic pyrolysis achieved a 79.08%liquid yield from high-density polyethylene(HDPE)at 550℃using Fe-HZSM-5 catalysts.Hydrocarbon selectivity was governed by catalyst acidity and pore structure.Hierarchical ZSM-5 further enhanced low-density polyethylene(LDPE)conversion(>95%)by mitigating overcracking through optimized pore architecture.The microwave pyrolysis demonstrated rapid heating kinetics,yielding a 98.78%aromatic-rich liquid fuel from polystyrene(PS)at 600 W with 60 g SiC absorbent.Monoaromatic hydrocarbons dominated the liquid fuel(93.9%),meeting aviation fuel standards.However,excessive power(>6 kW)reduced yields by 10%due to secondary decomposition.Photocatalytic depolymerization in 30%H_(2)O_(2)facilitated the production of acetic acid yield of 1.1 mmol·g^(-1)·h^(-1)from polyethylene(PE),utilizing hydroxyl radicals(·OH)to cleave C—C bonds,leading to an increase in PE mass loss from 50.1%to 85.4%.The key findings are as follows:(1)Fe doping in HZSM-5 boosted liquid yields by 16%via enhanced dehydrogenation activity;(2)Microwave absorber loading(e.g.,SiC)nonlinearly affected cycloparaffin selectivity(65.6%at 450 W for polypropylene);(3)H_(2)O_(2)increased photocatalytic PE conversion by 70%compared to pure water,where limited·OH generation restricted CO_(2)-to-fuel pathways(≤47.4μg·g^(-1)·h^(-1)).Catalytic pyrolysis faces the challenge of rapid catalyst deactivation(resulting in a 30%activity loss after 5 cycles),while microwave systems incur high capital costs.Photocatalysis prioritizes gaseous products(e.g.,H_(2),CH4)with liquid fuel selectivity below 15%for most polymers.To address these challenges,three actionable pathways are proposed:(1)Pilot-scale optimization:Current studies predominantly use lab-scale feeds(<100 g),necessitating trials with industrial-grade plastics containing pigments and plasticizers.Electrostatic separation pretreatment reduced PVC-derived HCl corrosion by 80%in pilot tests,while anti-fouling membranes(90%recovery)enhanced acetone purity(>98%)in continuous systems.(2)Hybrid energy systems:Integrating microwave heating(200–300℃/min)with photocatalysis may synergize rapid thermal activation and selective bond cleavage.For instance,microwave-enhanced light absorption in TiO_(2)-MoS2 hybrids doubled charge carrier density,potentially reducing energy consumption by 30%–40%.(3)Intelligent reactors:IoT-enabled sensors and machine learning algorithms stabilized multiphase reactions in simulated trials,minimizing yield fluctuations to±5%versus±15%in batch modes.Real-time monitoring of temperature gradients and microwave power enabled dynamic adjustments,improving diesel-range hydrocarbon selectivity by 25%.Economically,catalytic pyrolysis shows near-term viability with a break-even cost of 0.8–1.2$/L for diesel-range fuels,while photocatalysis requires a 50%–70%reduction in catalyst synthesis costs(e.g.,replacing Pt with Fe-Ni sulfides).Environmentally,microwave pyrolysis reduces carbon intensity by 40%–60%versus incineration,aligning with net-zero roadmaps.Lifecycle assessments revealed that hybrid systems could achieve carbon-negative profiles when coupled with renewable energy.Future work should focus on developing multifunctional catalysts(e.g.,acid-base bifunctional sites for tandem cracking-isomerization),modular reactor designs,and standardized testing protocols to expedite industrial implementation.These strategies underscore the potential of tailored energy-input systems to advance plastic valorization,supporting circular economies and global decarbonization efforts.
作者
李欣泽
骆治成
肖睿
LI Xinze;LUO Zhicheng;XIAO Rui(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,School of Energy and Environment,Southeast University,Nanjing 210096,China)
出处
《能源环境保护》
2025年第3期1-11,共11页
Energy Environmental Protection
基金
国家自然科学基金资助项目(52206236)
国家自然科学基金联合基金资助项目(U23A2090)
江苏省自然科学基金资助项目(BK20220837)
中央高校基本科研业务费专项资助项目(3203002211A1,2242024k30025)。
关键词
废塑料
高附加值利用
液体燃料
催化热解
微波热解
光催化解聚
Plastic waste
High value-added utilization
Liquid fuel
Catalytic pyrolysis
Microwave pyrolysis
Photocatalysis depolymerization
