采用热重-红外联用技术(TG-FTIR) 对比研究了陕北低变质粉煤(SJC) 与重油(HS) 、 焦煤(JM) 、 液化残渣(DCLR) 共热解过程中气相产物的析出特性。 研究表明, 随热解温度升高, SJC与HS, JM, DCLR的共热解过程均可分为三个阶段。 第一阶段表现为原料表面吸附物的释放, 第二阶段发生解聚和分解反应, 随温度继续升高, 第三阶段形成更为稳定的半焦。 在热解第二阶段中均存在煤与添加剂之间的协同效应, SJC作为主要的供氢体, 热解产生的氢自由基与HS, JM, DCLR热解产生的小分子自由基碎片之间发生相互作用生成焦油和煤气。 SJC和SJC+DCLR在450 ℃附近的温度区间内热解反应进行的更加充分, 大部分N元素转移到了焦油组分中。 热解过程气相产物中H2O和酚类物质、 含N杂环物质及CO的析出伴随着热解的整个温度区间, SJC+JM和SJC+HS热解过程含N物质的转移主要集中在400~650 ℃区间, CH4和脂肪烃类物质的析出最高峰出现在450 ℃附近, 而SJC+DCLR和SJC则出现在550 ℃。 JM, HS及DCLR的添加可促使焦油中芳香族化合物的析出, SJC+JM与SJC+HS热解过程芳香族物质大量析出的温度区间在400~550 ℃。 该研究结果为低变质粉煤的清洁转化与提质分级新技术的研究开发提供理论依据, 对低变质煤的增值利用具有重要的意义。Coupled with Fourier Transform Infrared Spectroscopy (FTIR)

The gaseous product release characteristic of the low-rank pulverized coal (SJC) in northern Shaanxi co-pyrolysis process with heavy oil (HS), coking coal (JM) and direct coal liquefaction residue (DCLR) were comparatively studied by the thermo-gravimetric analyzer (TG) coupled with fourier transform infrared spectroscopy (FTIR). The research showed that the SJC co-pyrolysis process with HS, JM and DCLR were divided into three stages, the first stage was the release of adsorbed substance from surface of the raw material, and the depolymerizing and decomposition reaction occurred in the second stage, and the third stage was the formation of a stabler semi-coke with the temperature increasing continuously. Coal and the additive have a synergistic effect during the second stage. As the major hydrogen donor, the SJC could generate the hydrogen free-radical in pyrolysis process interaction with small molecular free radical produced by HS, JM and DCLR pyrolysis process, and production of tar and gas. Around 450 ℃ temperature range, the pyrolysis process of SJC and SJC+DCLR were reacted more fully, and the majority of N element was transferred into the tar component. The gaseous product as water, phenols, heterocyclic nitrogen-containing compounds and CO of the pyrolysis process were released during the whole temperature interval of the pyrolysis. During the temperature of 400~650 ℃, the main reaction in the pyrolysis process of SJC+JM and SJC+HS was nitrogenous compounds transfer, the peak temperature of CH4 and aliphatic hydrocarbon compound release nearby 450 ℃, while the peak temperature of SJC+DCLR and SJC was 550 ℃. The aromatic compounds release in tar could be promoted by additive JM, HS and DCLR, generating a large amount of aromatic compounds during 400~550 ℃ in the pyrolysis process of SJC+JM and SJC+HS. The results of this study provided a theoretical foundation for the research and development of the new technology of low rank pulverized coal, which is of great significance to its value.