A method for producing low-condensation diesel oil using catalyst grading technology

Abstract

The invention discloses a method for producing diesel oil with a low condensation point by catalyst gradation technology. The method comprises the following steps: mixing a diesel oil raw material with hydrogen, orderly passing through at least two hydrogenation reaction zones connected in series, wherein in the material flowing direction, each hydrogenation reaction zone orderly comprises a hydrodewaxing catalyst bed layer, and a hydro-refining dewaxing catalyst composite bed layer filled with a mixture of a hydro-refining catalyst and a hydro-upgrading isodewaxing catalyst; performing separation and fractionation of the reaction effluent from the last hydrogenation reaction zone to obtain the diesel oil product with a low condensation point. The method of the invention reasonably combines and utilizes the temperature increase of the hydro-refining and hydro-upgrading dewaxing process with the temperature decrease of the hydrodewaxing process, improves the diesel oil yield and the cetane value while producing diesel oil with a low condensation point and low sulfur, reduces the hot-spot temperature of the device, prolongs the running period, also reduces the cold hydrogen consumption or the combustion gas loss of a heating furnace, and saves operation cost.

Description

Technical field [0001] The invention relates to a method for producing low-pour-point diesel, in particular to a hydrogenation method for producing low-pour-point diesel through catalyst grading technology and composite filling technology. Background technique [0002] Diesel, as the fuel of compression ignition engines, plays an irreplaceable role as a non-renewable resource in the modern production and life process. It can be used as vehicles, tanks, airplanes, tractors, railway vehicles and other vehicles or other machinery. Fuel can also be used for power generation and heating. According to the different industries and environments, users also have very different quality requirements for diesel products. For people living in alpine regions or winter, the demand for low-freezing point diesel has always been high. The traditional choice The cracking process can process waxy heavy diesel fractions, and the pour point reduction range can reach 20-50 ℃. While obtaining low freez...

AI Technical Summary

Problems solved by technology

In this method, the temperature drop in the bed of the hydrodepreciation catalyst is relatively large, and the yield of the diesel fraction and the improvement of the depreciation effect are limited to a certain extent, which reduces the service life of the hydrodecondensation catalyst.

[0006] CN102051232A introduces a method for diesel hydrotreating decondensation. This method is to adjust the properties of the catalyst so that the effect of diesel decondensation is good and the yield of diesel fractions is high. The combination process, the contradiction between the pour point depressing effect and the diesel fraction yield still exists

[0008] The reaction temperature at the outlet of each bed layer is still relatively high, and the cycle is limited to a certain extent

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