煤直接液化残渣催化热解过程中官能团演变特性研究

Evolution Characteristics of Functional Groups during Catalytic Pyrolysis of Direct Coal Liquefaction Residue

采用原位红外催化反应装置,利用傅里叶变换红外光谱仪(FT-IR),以CaCl_(2)·6H_(2)O、FeCl_(3)·6H_(2)O和Cs_(2)SO_(4)为催化剂,对比分析了添加3种不同催化剂以及不同含量的Fe^(3+)在煤直接液化残渣(DCLR)催化热解过程中官能团的演变特性。结果表明:3种催化剂一定程度上都促进了DCLR的缩聚反应;对于以FeCl_(3)·6H_(2)O为催化剂的样品,当热解温度为500℃左右时苯骨架结构峰位由1546 cm^(-1)向1600 cm^(-1)偏移,表明DCLR内的缩聚反应大于分解反应,其芳香骨架结构缩聚程度提高,稠环体系变大;对比不同浓度FeCl_(3)·6H_(2)O在升温过程中对脂肪侧链甲基和亚甲基在热解过程中的催化效果,发现Fe^(3+)在DCLR热解过程中对脂肪族甲基的脱除起到了抑制作用,且随着样品中Fe^(3+)含量的增加(在质量分数为1%~10%时),其抑制作用越强。

Using in situ infrared catalytic reaction device and Fourier transform infrared spectrometer(FT-IR),CaCl_(2)·6H_(2)O,FeCl_(3)·6H_(2)O and Cs_(2)SO_(4) as catalysts,the evolution characteristics of functional groups during catalytic pyrolysis of DCLR by adding three different catalysts and different content of Fe^(3+)were compared and analyzed.The results showed that the three catalysts all promoted the polycondensation of DCLR to some extent;for the sample with FeCl_(3)·6H_(2)O as catalyst,the peak of benzene skeleton structure shifted from 1546 cm^(-1) to 1600 cm^(-1) when the pyrolysis temperature was about 500℃,indicating that the polycondensation reaction in DCLR was greater than the decomposition reaction,the degree of polycondensation of aromatic skeleton structure increased,and the thickened ring system increased;by comparing the catalytic effects of different concentrations of FeCl_(3)·6H_(2)O on the pyrolysis of aliphatic methyl and methylene during the heating process,it was found that Fe^(3+)inhibited the removal of aliphatic methyl during the pyrolysis of DCLR,and with the increase of the content of Fe^(3+)in the sample(within the mass fraction range of 1%~10%),the stronger the inhibition effect.