Process for hydrogenating and refining coking diesel oil

Abstract

The invention discloses a process for hydrogenating and refining coking diesel oil. The process is implemented by the aid of fixed-bed reactors. The fixed-bed reactors are filled with hydrogenation, desulfurization and denitrification catalysts, and the catalysts comprise carriers and active components; the carriers are SAPO (silicoaluminophosphate)-5, and hetero atoms Cu2+ are doped in synthesis skeleton structures of the SAPO-5; the active components are mixtures of di-molybdenum nitride MO2N, tungsten nitride W2N, molybdenum carbide Mo2C and tungsten carbide WC; the catalysts further comprise catalytic auxiliaries, and the catalytic auxiliaries are mixtures of TiO2, CeO2, V2O5 and NbOPO4; reaction conditions of the fixed-bed reactors include that the reaction temperatures are 300-450 DEG C, the hydrogen partial pressures are 6-9 MPa, the hydrogen-to-oil volume ratios are 450-700, and the volume space velocities are 1.5-3 h<-1>. The process has the advantages that the content of total sulfur in the coking diesel oil can be lower than 5 ppm under the control, and the service lives of the catalysts can be prolonged and reach 8 a at least.

Description

technical field [0001] The invention relates to a coking diesel hydrodesulfurization refining process, in particular to a coking diesel hydroprocessing refining process using a specific catalyst. Background technique [0002] The delayed coking process is based on heavy oil, such as vacuum residue, cracked residue, etc., as raw materials, thermal cracking and condensation reaction at high temperature (about 500 ° C), to produce gas, gasoline, diesel oil, wax oil and petroleum coke. [0003] Coking diesel oil has high sulfur content and olefin content, and cetane number is higher than that of catalytic diesel oil, but it is very unstable, easy to change color (oxidation), and has many impurities. After stabilization, coking diesel oil can only be used as a semi-finished product, and generally needs to be hydrotreated , to remove nitrogen-containing, sulfur-containing compounds and dienes, it can be used as a vehicle diesel blending component or as a petrochemical raw materia...

AI Technical Summary

Problems solved by technology

[0005] In the existing desulfurization process, hydrofining has been widely used due to its mature environment-friendly technology. However, the sulfur content of the raw materials targeted by the existing hydrogenation process is mostly at the level of several hundred ppm. Sulfur content, the catalyst used in the existing hydrorefining process is difficult to adapt to such a high sulfur content, generally there will be two problems: one is that the activity of the catalyst decreases rapidly, and the catalyst’s degradation rate when the device is processing other raw materials The service life can reach 6a (6 years) or even longer, but after processing coked diesel, the service life of the catalyst is only 1-2a

[0006] After analysis, it is found that when the catalyst used in the existing hydrofinishing is used for the hydrofinishing of coked diesel oil, the loss of the metal components of the catalyst is relatively large, indicating that the active components on the catalyst are reduced, and the pore volume becomes much smaller, resulting in the reaction between the reactant and the catalyst. The contact area of ​​the catalyst decreases, which is directly reflected in the decrease of the catalyst activity

At the same time, when producing ethylene feedstock, reformate feedstock, and synthetic ammonia feedstock, coking diesel oil requires high operating severity and high hydrogenation depth, which leads to intensified carbon deposition in the catalyst bed and a rapid increase in pressure drop