关键词: 沥青质, 蜡油加氢, 长周期运行, 温度翘尾

Abstract: The catalyst deactivation rate of a 3.2 MMTPY wax oil hydrotreating unit in a certain company is as high as 2.16℃/month. After analysis, it is found that the significant increase of asphaltene content in feedstock is the main reason for the rapid deactivation of the catalyst in the unit. Based on the molecular model of asphaltene and the principle of catalyst deactivation, a comparative analysis is conducted on the catalyst deactivation rates when the asphaltene mass fraction in feedstock is at 200, 500, 2800 μg/g, and the hydrogen partial pressure is at 9.0 MPa and 11.0 MPa, respectively. Measures to extend the operating cycle of the unit are proposed. According to the principle of catalyst deactivation, it is proposed that for the wax oil hydrotreating unit with a hydrogen partial pressure less than 10.5 MPa, the mass fraction of asphaltene in feedstock should be controlled at less than 500 μg/g, and the operating cycle of the unit can reach 4 years. When the mass fraction of asphaltene in feedstock is reduced to below 300 μg/g and a suitable catalyst grading scheme is matched, the carbon deposition on the catalyst surface can reach a steady-state equilibrium, achieving ultra-long cycle operation of the unit.

Key words: asphaltene, wax oil hydrotreating, long cycle operation, temperature rise