有机组分原位再吸附对生物质-褐煤燃料品质调控研究

In-situ Redistribution of Organic Components for Regulating the Fuel Quality of Biomass-Lignite Blends

摘要

面对化石能源渐趋枯竭与生态压力持续加剧的双重挑战，可再生能源已被各国提升至能源战略核心，其中储量庞大、可循环再生的生物质尤受瞩目，其高效转化与规模化应用被认为是应对能源与环境双重挑战的关键路径。生物质与褐煤混合掺烧是一种可行性很强的利用手段。针对褐煤高含水、易自燃及提质后复吸难题，本文以云南小龙潭褐煤与河南小麦秸秆为原料，在固定床中经空气和氩气气氛、 170∼270^∘C 共烘焙 30 min 制备 0∼100% 掺混的联合提质燃料。利用热重、动力学计算、BET、SEM、接触角及水分复吸实验系统评估其燃烧反应性与疏水性能。结果表明，空气气氛下 75% 生物质掺混并于 220^∘C 提质效果最佳：改性燃料着火与燃尽温度分别降低 149.6^∘C 和 90.5^∘C，平均活化能降至 99.7 kJ/mol；生物质焦油在煤粒表面形成致密覆层，改性燃料疏水性明显增强，水接触角为 135.1^∘；过度升温或惰性气氛会破坏焦油膜完整性导致水分复吸率回升。该工艺以廉价生物质副产物替代石化添加剂，可以实现褐煤低能耗提质与长周期储运，为低阶煤和农林固体废弃物清洁、高效资源化利用提供新的途径。

Abstract

In response to the dual challenges of depleting fossil fuel reserves and escalating ecological pressures， renewable energy has been elevated to the core of national energy strategies.Among various renewable sources， biomass characterized by its abundant reserves and renewable nature has attracted particular attention.Its efficient conversion and large-scale utilization are regarded as key pathways for addressing both energy and environmental challenges.Blending and co-firing with lignite is a usable method.To address the problems of high moisture con-tent，easy spontaneous combustion and re-absorption after quality improvement of lignite，this paper uses lignite from Xiaolongtan，Yunnan Province and wheat straw from Henan Province as raw materials to prepare a blended fuel with improved quality at a 0-100% blending ratio by torrefying them in a fixed bed at 170-270^∘C for 30 minutes under an air or argon atmosphere..The combustion reactivity and hydrophobic performance were evalu-ated by thermogravimetric，kinetic calculation，BET，SEM，contact angle and moisture re-absorption test systems.The results show that the optimal quality improvement is achieved when 75% biomass is mixed at 220^∘C in an air atmosphere.The ignition and burnout temperatures decrease by 149.6^∘C and 90.5^∘C respectively，and the average activation energy drops to 99.7 kJ/mol.Tar derived from biomass forms a dense hydrophobic film on the surface of coal particles，resulting in strong hydrophobicity with a water contact angle of 135.1^∘，which is significantly supe-rior to traditional asphalt/petroleum coke modification.Excessive heating or an inert atmosphere can damage the integrity of the tar film，leading to a rebound in the reabsorption rate.This technology will substitute petrochemical additives for inexpensive biomass by-products，enabling low-energy consumption upgrading and long-term storage and transportation of lignite.It provides a new pathway for the clean and efficient resource utilization of low-rank coal and agricultural and forestry solid waste.

关键词

褐煤 / 生物质 / 燃料品质 / 燃烧特性 / 疏水性

Key words

lignite / biomass / fuel quality / combustion characteristics / hydrophobicity

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基金资助

安徽省质量基础设施标准化专项资助项目(2023MKS19)