Abstract: Aiming at the poor operational stability of the topping unit for catalytic cracking slurry (referred to as slurry) in a certain enterprise, the key factors affecting the long-term stable operation of the unit were systematically explored. The results show that the properties of the slurry feedstock, the accuracy of parameter control, and the structure of core equipment are the main factors restricting the operational stability of the slurry topping unit. The mass concentration of solid impurities in the slurry should be controlled below 6 g/L, the temperature of the vacuum distillation column should be controlled at (290 ± 5) ℃, and the top pressure should be controlled at -98 to -96 kPa. Further, based on the analysis results, multiple equipment renovations, vacuum system optimization, operation parameter optimization, and energy consumption structure analysis were carried out on the unit, and countermeasures were formulated for the problems existing in the operation of the unit. The results show that after upgrading the trays, adding an oil collection tank, replacing the steam distributor and riser, adding a valve group to the vacuum system, implementing online monitoring of the slurry feedstock properties, upgrading the material of the slurry pump valve, and on-site monitoring of wastewater, the separation efficiency of light and heavy slurry in the slurry topping unit has significantly improved, the yield of heavy slurry has been significantly enhanced, the quality of the hot mix asphalt regenerant has met the standards, and the stable operation time of the unit has been greatly increased.

Key words: slurry pulling device, yield of hot mix asphalt regenerant, optimizing operation, unit stability