摘要
催化裂化沉降器结焦将导致非计划停工,严重影响催化裂化装置的长周期运行。首先求取了单位时间沉降器内冷凝的油浆液滴的质量,然后利用颗粒轨道模型对液滴的运动轨迹进行模拟计算,得到液滴的停留时间、运动轨迹和分布区域。模拟计算结果表明,液滴在沉降器内的运动具有很强的随机性,不同大小的油浆液滴的停留时间不同,但大部分的液滴粘附在沉降器内壁和旋风分离器外壁上,进而缩合结焦。加强沉降器的保温可减少油气重组分的冷凝,采用“高温汽提”和“化学汽提”可减少进入沉降器的油气重组分的量,从而减少沉降器结焦。
The coking within FCC disengager can result in unscheduled shut-downs of FCC with consequent adverse effects on their long-term operation. In this paper, the quantity of liquid droplets condensed from heavy fractions of FCC products due to temperature decrease was calculated, and a particle-trajectory model was used to simulate the flow tracks of these droplets. Then the residence time, flow track and distributing region of the liquid droplets were obtained. The simulation results show that the droplets flow randomly in the disengager, and the droplets with different diameters have different residence time, but most droplets adhere to the disengager internal surface and the cyclone external surfaces and then are involved in the condensation reactions to form coke. The enhancement of the heat preservation in the disengager can reduce the condensation of heavy fractions. ＂High temperature stripping＂ and ＂chem.-stripping＂ can decrease the heavy fractions of gaseous oil products entering the disengager. The application of the above two methods can alleviate coking.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2007年第3期423-428,共6页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金(20406013)
关键词
沉降器
结焦
液滴
颗粒轨道模型
运动轨迹
disengager
coking
droplet
particle-trajectory model
flow track
