高硫石油焦高温热解过程及硫析出特性研究

为深入了解高硫石油焦在工业应用高温工况下的热解过程以及硫的析出特性,本研究采用高温固定床对青岛高硫石油焦进行了高温(900-1500℃)热解实验,考察了高温热解下热解气体释放规律,热解过程中焦的物理孔隙结构以及化学特性的演变,并对热解过程中硫的析出与演变特性进行了研究。结果表明,随着热解温度的升高,石油焦热解气中的H_2含量逐渐增加,CO含量变化不大,CH_4与CO_2含量则逐渐下降;热解焦的比表面积与平均孔隙均随热解温度的升高有所增加,颗粒的表面形态则受温度影响较小;热解温度的升高会降低石油焦中含有的非定型碳比例,提高其微晶结构的有序性以及石墨化程度;热解焦的气化活性随热解温度的升高先降低后升高,在1100℃附近有最小值; 1500℃高硫石油焦硫元素析出率达81.34%,仅少量硫醇类有机硫和噻吩环内的硫元素得以残存。

Study on high temperature pyrolysis process and sulfur transformation property of high sulfur petroleum coke

In order to understand the pyrolysis process and sulfur transformation property of high sulfur petroleum coke at high temperature, the pyrolysis experiment of Qingdao high sulfur petroleum coke at high temperature (900-1500℃) was carried out in a high temperature fixed bed. The release rule of pyrolysis gas and the evolution of physical pore structure and chemical characteristics of coke during pyrolysis were investigated. At the same time, the content and existing mode of sulfur in the samples before and after pyrolysis were studied. The results show that with the increase in pyrolysis temperature, the content of H₂ in the pyrolysis gas of petroleum coke increases gradually; the content of CO changes little; while the content of CH₄ and CO₂ decreases gradually. Moreover, as the pyrolysis temperature is increased, the specific surface area and average porosity of pyrolysis coke increase; the surface morphology of particles is less affected; the content of amorphous carbon in petroleum coke reduces; and the order and graphitization degree of microcrystalline structure increase gradually. However, with the increase in pyrolysis temperature, the gasification activity of pyrolysis coke is first decreased and then increased, with the minimum value around 1100℃. It is found that the sulfur release rate in high sulfur petroleum coke pyrolysis at 1500℃ reaches 81.34%, and only a small amount of organic sulfur in the form of mercaptans and thiophene rings is retained in solid.