不同煤化程度煤与气化细渣混合燃烧特性分析

Analysis of Mixed Combustion Characteristics of Coal with Different Degree of Coalification and Coal Gasification Fine Slag

摘要

为提升气化细渣(CGFS)燃烧热回收效率,通过热重分析(TGA)、管式炉及鼓泡流化床试验装置,探究不同煤化程度煤对CGFS燃烧特性的影响．TGA显示,褐煤与CGFS燃烧区间差异明显,混合燃烧呈现“分阶段燃烧”．随着原煤占比的增加,点火温度(T_i)和燃尽温度(T_b)显著降低,综合燃烧特性指数(S)、燃尽指数(D_b)、可燃性指数(C)整体提升,表明原煤有效改善了CGFS燃烧性能．随着原煤煤阶的升高,共燃烧相互作用由拮抗向协同转变．通过Flynne-Walle-Ozawa(FWO)和Kissinger-Akahira-Sunose(KAS)拟合表明,原煤的加入显著降低混合体系平均活化能．管式炉燃尽评估表明,褐煤与烟煤的加入使混合体系的燃烧速率均低于任一单组分；而无烟煤则通过协同作用提升燃烧速率．此外,升温速率的提高不仅通过缩短热滞后效应来增强燃烧强度,还通过促进挥发分与固定碳的连续释放显著改善燃尽能力．流化床燃烧试验表明,高含量的挥发分会使燃烧效果更好；无烟煤因固定碳含量高,点火阶段碳氧反应能垒较大,燃烧效果受限．

Abstract

To enhance the combustion heat recovery efficiency of coal gasification fine slag(CGFS), this study investigated the effects of coals with different degrees of coalification on the combustion characteristics of CGFS using thermogravimetric analysis(TGA), tube furnace, and bubbling fluidized bed testing equipment. TGA results showed significant differences in the combustion behavior of lignite and CGFS, with distinct “phased combustion” characteristics during co-combustion. With the increasing proportion of raw coal, both ignition temperature(T_i) and burnout temperature(T_b) decreased significantly. Simultaneously, comprehensive combustion characteristic index(S), burnout index(D_b), and flammability index(C) exhibited an overall upward trend, which suggests that the incorporation of raw coal substantially enhances the combustion performance of CGFS. With the increase in raw coal rank, the co-combustion interaction transitions from an antagonistic to a cooperative one. The fitting results of Flynne-Walle-Ozawa(FWO) and Kissinger-Akahira-Sunose(KAS) indicate that the addition of raw coal significantly reduces the average activation energy of the mixed system. The evaluation of tube furnace burnout results indicates that the combustion rate of the mixed coal system is lower than that of any single component when lignite and bituminous coal are added. However, anthracite enhances the combustion rate via a synergistic effect. In addition, the elevated heating rate not only intensifies combustion by mitigating the thermal lag effect but also markedly enhances burnout performance through the promotion of sustained volatile and fixed carbon release. The results of the fluidized bed combustion test indicate that high volatile matter content contributes to more efficient combustion. However, due to the high fixed carbon content, anthracite presents a pronounced energy barrier during the carbon-oxygen reaction in the ignition phase, thereby limiting its combustion efficiency.

关键词

气化细渣 / 混合燃烧 / 热重分析 / 燃烧特性 / 燃尽性能 / 鼓泡流化床

Key words

coal gasification fine slag / mixed combustion / thermogravimetric analysis / combustion characteristics / burnout performance / bubbling fluidized bed

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基金资助

国家自然科学基金资助项目(51974311)

宁夏自然科学基金资助项目(2025AAC020012)