Real-Time Emission, Chemical Properties, and Dynamic Evolution Mechanism of Volatile Organic Compounds during Co-Pyrolysis of Rice Straw and Semi-Bituminous Coal,ACS ES&T Engineering

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Real-Time Emission, Chemical Properties, and Dynamic Evolution Mechanism of Volatile Organic Compounds during Co-Pyrolysis of Rice Straw and Semi-Bituminous Coal
ACS ES&T Engineering ( IF 7.4 ) Pub Date : 2023-01-04 , DOI: 10.1021/acsestengg.2c00391
Tingting Li _{1,

2} , Fanhao Song ₂ , Yingchen Bai ₂ , Fengchang Wu ₂ , Mingqi Ruan ₂ , Yuhan Cao _{2,

3} , Lingfeng Zhou ₂ , Fuhong Sun ₂

Affiliation

The co-pyrolysis of biomass–coal blends improves energy utilization efficiency; however, the synergistic mechanisms behind thermal degradation and volatile formation remain unclear. We combined online thermogravimetry–Fourier transform infrared spectrometry–gas chromatography/mass spectrometry (TG–FTIR–GC/MS), Gaussian deconvolution, and two-dimensional correlation spectrometry (2D-COS) to reveal the component degradation, sequential response, and evolution mechanism of volatiles during co-pyrolysis of rice straw (RS) and semi-bituminous coal (SBC), which were mixed in three proportions of 1:3, 1:1, and 3:1. The activation energies (24.70–53.43 kJ mol^–1) and preexponential factors (44.67–7663.43 min^–1) for decomposition and average emission intensity coefficient (EIC) (0.06–0.12) of volatiles exhibited significant heterogeneity and were highly dependent on pyrolysis temperature and blend proportion. The EIC values of phenols/esters, alcohols/ethers, ketones, aldehydes, and acids increased with increasing RS proportion. The volatile distribution of blends with high SBC proportions was mainly located in the decarbonylation/dehydration reaction region. Moreover, the volatile organic compound (VOC) and intermediate VOC percentages were 59–83 and 17–39%, respectively, with N-containing species contributing the most to the intermediate VOC fraction. Most of the volatiles mainly exhibited reducing character, with average carbon oxidation state below zero. An increase in the proportion of RS and SBC contributed to high unsaturation and small carbon skeletons of volatiles, respectively. Notably, the primary sequential temperature response of volatiles was hydrocarbons, alcohols/phenols/ethers/esters, and (aldehydes/ketones/acids, aromatics), in that order. Furthermore, we proposed a novel synergistic mechanism to demonstrate that the heterogeneous degradation of RS/SBC components contributed significantly to the dynamic formation of volatiles during the co-pyrolysis process. These novel insights into the mechanisms of biomass–coal co-pyrolysis are useful for energy optimization and pollution control.

中文翻译：

稻草与半烟煤共热解过程中挥发性有机化合物的实时排放、化学性质及动态演化机制

生物质-煤混合物的共热解提高了能源利用效率；然而，热降解和挥发物形成背后的协同机制仍不清楚。我们结合在线热重分析法-傅里叶变换红外光谱法-气相色谱/质谱法 (TG-FTIR-GC/MS)、高斯反卷积和二维相关光谱法 (2D-COS) 来揭示组分降解、顺序响应和演变稻草(RS)和半烟煤(SBC)按1:3、1:1和3:1三种比例混合共热解过程中挥发物的机理。活化能 (24.70–53.43 kJ mol ^–1 ) 和指前因子 (44.67–7663.43 min ^–1) 的分解和挥发物的平均排放强度系数 (EIC) (0.06–0.12) 表现出显着的异质性，并且高度依赖于热解温度和混合比例。酚/酯、醇/醚、酮、醛和酸的 EIC 值随着 RS 比例的增加而增加。具有高SBC比例的共混物的挥发性分布主要位于脱羰基/脱水反应区域。此外，挥发性有机化合物 (VOC) 和中间 VOC 的百分比分别为 59-83 和 17-39%，其中含氮物质对中间 VOC 的贡献最大。大多数挥发物主要表现出还原性，平均碳氧化态低于零。RS 和 SBC 比例的增加分别导致挥发物的高不饱和度和小碳骨架。值得注意的是，挥发物的主要顺序温度响应依次是碳氢化合物、醇/酚/醚/酯和（醛/酮/酸、芳烃）。此外，我们提出了一种新的协同机制来证明 RS/SBC 组分的非均相降解对共热解过程中挥发物的动态形成有显着影响。这些对生物质-煤共热解机制的新见解可用于能源优化和污染控制。以该顺序。此外，我们提出了一种新的协同机制来证明 RS/SBC 组分的非均相降解对共热解过程中挥发物的动态形成有显着影响。这些对生物质-煤共热解机制的新见解可用于能源优化和污染控制。以该顺序。此外，我们提出了一种新的协同机制来证明 RS/SBC 组分的非均相降解对共热解过程中挥发物的动态形成有显着影响。这些对生物质-煤共热解机制的新见解可用于能源优化和污染控制。

更新日期：2023-01-04

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