原料组成对针状焦结构的影响

Study on the influence of raw material composition on the structure of needle coke

在330–390°C、8 MPa、加氢时间为1.5 h和剂油比为1∶40的条件下对中低温煤焦油原料进行加氢处理,得到精制原料后再通过热聚合煅烧等过程制得针状焦。通过元素分析、红外光谱(FT-IR)、气相色谱-质谱联用仪(GC-MS)等检测方法分析了精制原料组成,并采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和偏光显微镜等方法测试了不同原料所制备出的针状焦结构,研究了加氢温度和精制原料组成对针状焦结构的影响。结果表明,提高缓和加氢精制温度有利于脱除杂原子(尤其是S),但当加氢温度为390°C时,原料中的芳烃会因为裂解和缩聚而发生两极分化。此外,精制原料中3环和4环芳烃的含量越高,所制备出针状焦石墨化程度越高。

The refined raw material was first prepared from the low-medium temperature coal tar through hydrogenation for 1.5 h under 330–390°C and 8 MPa,with a catalyst/oil mass ratio of 1∶40,which was then used to produce needle coke through thermal polymerization and calcination.The composition of refined raw materials was analyzed by elemental analysis,Fourier-transform IR spectroscopy(FT-IR)and gas chromatography-mass spectrometry(GC-MS)and the structure of needle coke was characterized by scanning electron microscope(SEM),X-ray diffractometer(XRD)and polarizing microscope;the effect of raw material composition(related to the hydrogenation temperature)on the structure of needle coke was then investigated.The results indicate that a proper increase in the hydrofining temperature is beneficial to the removal of heteroatoms(especially sulfur).By hydrogenation at 390°C,the aromatics in the feedstock are polarized due to the cracking and polycondensation.In addition,a higher content of tricyclic and tetracyclic aromatics in the refined raw materials may also lead to a higher graphitization degree for the needle coke product.