Abstract Three-stage thermal reactions were conducted to investigate empirical trends of petroleum-based pitch production and the chemical characteristics of pitch produced by controlling the temperature and pressure operating parameters. The softening point of pitch increased with increasing reaction temperature under atmospheric pressure, whereas the pitch yield increased with decreasing reaction temperature under a pressurized condition. Elemental analysis supported the result of decreased hydrogen content. In addition, thermogravimetric analysis revealed that higher reaction temperatures could induce the polymerization and condensation of polyaromatic hydrocarbons (PAHs) with carbon yield at 900 °C. The molecular weight distribution (MWD) of pitch was analyzed by MALDI-TOF analysis according to the operating parameters during the thermal reaction. The MALDI-TOF spectrum was normalized to observe the variation in the MWD by Anthracene (178 Da) as a pseudo-component. Range 2–3 and range 6–8 in the MWD coincided with the trends of the pitch yield and the softening point, respectively. The results suggested that pitch yield is related to the PAHs with 2–6 aromatic rings and that the softening point is related to highly condensed PAHs with more than 6 aromatic rings. The anisotropy/isotropy of the pitch was analyzed by polarized light microscopy. The pitch produced under the pressurized condition was isotropic. However, the pitch produced under atmospheric pressure exhibited a well-oriented domain texture. We concluded that volatile contents disturb the polymerization and condensation of PAHs because of side reactions involving the aliphatic contents.

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通过压力和温度控制的热反应生产石油基沥青的实证研究

摘要 通过三级热反应研究石油基沥青生产的经验趋势和控制温度和压力操作参数生产的沥青的化学特性。在常压下，沥青的软化点随着反应温度的升高而增加，而在加压条件下，沥青的产率随着反应温度的降低而增加。元素分析支持氢含量降低的结果。此外，热重分析表明，较高的反应温度可以诱导多环芳烃 (PAH) 的聚合和缩合，碳产率为 900 °C。根据热反应过程中的操作参数，通过MALDI-TOF分析来分析沥青的分子量分布(MWD)。将 MALDI-TOF 光谱归一化以观察作为伪组分的蒽 (178 Da) 的 MWD 变化。MWD 的范围 2-3 和范围 6-8 分别与沥青屈服和软化点的趋势一致。结果表明，沥青产率与具有 2-6 个芳环的 PAH 相关，软化点与具有 6 个以上芳环的高度稠合的 PAH 相关。通过偏光显微镜分析沥青的各向异性/各向同性。在加压条件下生产的沥青是各向同性的。然而，在大气压下生产的沥青表现出定向良好的域纹理。