Coker diesel hydrofining process

Abstract

The invention discloses a coker diesel hydrofining process. A fixed bed reactor is adopted in the process, the fixed bed reactor is filled with a hydrodesulfurization and denitrification catalyst, and the catalyst comprises a carrier and an active component. The carrier is a compound or mixture of MSU-G, SBA-15 and HMS. The active component is a mixture of molybdenum nitride (MO2N), tungsten nitride (W2N), molybdenum carbide (Mo2C) and tungsten carbide (WC); the catalyst further contains a catalytic addictive, and the catalytic addictive is a mixture of TiO2, CeO2, V2O5 and NbOPO4. According to the reaction conditions of the fixed bed reactor, the reaction temperature ranges from 300 DEG C to 450 DEG C, the hydrogen partial pressure ranges from 6 MPa to 9 MPa, the hydrogen-oil volume ratio ranges from 450 to 700, and the volume velocity ranges from 1.5 h<-1> to 3 h<-1>. According to the process, the total sulphur content of coker diesel can be controlled to be smaller than 5 ppm, and the service life of the catalyst can be prolonged to 8 a or above.

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