In this study, coke deposits during thermal cracking of light naphtha in the presence of sulfur‐ and sulfur/phosphorous‐containing compounds with different addition methods were investigated from the points of morphology and structure. Sulfur/phosphorous‐containing compounds were applied by continuous addition, pretreatment, and pretreatment followed by continuous addition. As for continuous addition, the amount of coke was decreased with increasing the mass concentration of sulfides in short‐term cracking periods. Catalytic coke was inhibited because of passivating the metal by sulfides at the initial stage of coking process. When phosphides were combined with the mixture of sulfides, the coke formation was further decreased as the synergistic effects of adsorption of sulfur and phosphorous onto the metal led to the decreased activity of metal surface. In the case of pretreatment with sulfur/phosphorous, the reduction in coke formation at the initial stage of cracking process was due to the adsorption of S/P‐containing radicals on the oxide film. In further cracking operation, an enrichment of Fe and Ni in the oxide layer from the pretreatment process leads to the appearance of coke filaments in coke layers. The combined addition method, the surface pretreatment with dimethyl disulfide (DMDS)/triphenyl phosphite (TPPI) followed by continuous addition of sulfides/TPPI in the feed, shows the best coking inhibition performance. The inhibition rate is up to 88.8% and 78.5% respectively when the cracking time is 1 and 3 h. The combined application strengthened the coverage of catalytic activity sites by sulfur/phosphorous‐containing radicals. The scanning electron microscope (SEM) results showed that the structural characteristics of coke deposit at the applied conditions were mainly amorphous coke. Variant coke filaments were also observed at the conditions of pretreatment and pretreatment followed by continuous addition. The analyses of Raman spectra indicated that the application methods decreased the graphitization degree of coke deposited and increased the structure defects of the coke matrix. During naphtha cracking, sulfur/phosphorous‐containing compounds reduced dehydrogenation and condensation by which hydrocarbons were degraded to coke.

中文翻译：

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轻石脑油热裂解过程中硫化物和含硫/磷化合物对焦炭形成的影响

在这项研究中，从形态和结构的角度研究了轻质石脑油在存在硫和含硫/磷化合物的情况下热裂解过程中的焦炭沉积物。通过连续添加，预处理和预处理，然后连续添加来施用含硫/磷的化合物。至于连续添加，焦炭的数量随着短期裂解期硫化物质量浓度的增加而减少。由于在焦化过程的初期，硫化物使金属钝化，因此抑制了催化焦炭的产生。当磷化物与硫化物混合物混合时，由于硫和磷吸附到金属上的协同作用导致金属表面活性降低，焦炭形成进一步减少。在用硫/磷进行预处理的情况下，裂解过程初期焦炭形成的减少是由于含S / P的自由基吸附在氧化膜上。在进一步的裂化操作中，来自预处理过程的氧化物层中的铁和镍的富集导致在焦炭层中出现焦炭丝。联合添加方法，即用二甲基二硫（DMDS）/亚磷酸三苯酯（TPPI）进行表面预处理，然后在进料中连续添加硫化物/ TPPI，显示出最佳的焦化抑制性能。裂解时间为1 h和3 h时，抑菌率分别达到88.8％和78.5％。联合应用增强了含硫/含磷自由基对催化活性位点的覆盖。扫描电子显微镜（SEM）结果表明，在应用条件下，焦炭沉积物的结构特征主要为非晶态焦炭。在预处理和预处理，然后连续添加的条件下，还观察到变焦炭丝。拉曼光谱分析表明，该方法降低了焦炭沉积的石墨化程度，增加了焦炭基质的结构缺陷。在石脑油裂解过程中，含硫/磷的化合物减少了脱氢和冷凝，从而使烃降解为焦炭。扫描电子显微镜（SEM）结果表明，在应用条件下，焦炭沉积物的结构特征主要为非晶态焦炭。在预处理和预处理，然后连续添加的条件下，还观察到变焦炭丝。拉曼光谱分析表明，该方法降低了焦炭沉积的石墨化程度，增加了焦炭基质的结构缺陷。在石脑油裂解过程中，含硫/磷的化合物减少了脱氢和冷凝，从而使烃降解为焦炭。扫描电子显微镜（SEM）结果表明，在应用条件下，焦炭沉积物的结构特征主要为非晶态焦炭。在预处理和预处理，然后连续添加的条件下，还观察到变焦炭丝。拉曼光谱分析表明，该方法降低了焦炭沉积的石墨化程度，增加了焦炭基质的结构缺陷。在石脑油裂解过程中，含硫/磷的化合物减少了脱氢和冷凝，从而使烃降解为焦炭。在预处理和预处理，然后连续添加的条件下，还观察到变焦炭丝。拉曼光谱分析表明，该方法降低了焦炭沉积的石墨化程度，增加了焦炭基质的结构缺陷。在石脑油裂解过程中，含硫/磷的化合物减少了脱氢和冷凝，从而使烃降解为焦炭。在预处理和预处理，然后连续添加的条件下，还观察到变焦炭丝。拉曼光谱分析表明，该应用方法降低了焦炭沉积的石墨化程度，增加了焦炭基体的结构缺陷。在石脑油裂解过程中，含硫/磷的化合物减少了脱氢和冷凝，从而使烃降解为焦炭。