Wet starting method of hydrocracking unit

Abstract

The invention relates to a wet starting method of a hydrocracking unit. A reaction zone of the hydrocracking unit is filled with a sulfurization type hydrogenation catalyst. The starting method comprises steps of heating starting oil through heat exchange to a certain temperature, passing the starting oil through a catalyst bed layer to raise the temperature of the catalyst bed layer to be 180+ / -15 DEG C or higher by utilization of the heat of reactions during heat exchange and activation, blending a part of gas with a high olefin content into circulating gas, raising the temperature continuously to 230+ / -15 DEG C by utilization of the heat of olefin hydrogenation reactions and activating at the constant temperature, introducing nitrogen-containing light distillate oil when the temperature is 245+ / -15 DEG C, introducing nitrogen-containing heavy distillate oil instead when the temperature is 290+ / -15 DEG C or higher, introducing raw oil instead step by step when the temperature is 320+ / -15 DEG C, raising the temperature continuously by utilization of the heat of hydrogenation reactions of the raw oil, and finally adjusting the reaction temperature by the hydrogen cooling amount and a heat exchanger and shifting to normal production. Compared with the prior art, the starting method omits a heating furnace in the starting process of the hydrocracking unit and the starting process is smooth and steady.

Description

technical field [0001] The invention belongs to a processing method of oil refining technology, in particular to a hydrocracking unit wet start-up method. Background technique [0002] With the increasingly stringent environmental regulations around the world, there is an increasing demand for clean, light, and clean fuels. Hydrogenation technology is an effective means of producing clean products. Therefore, hydrogenation units have become the standard configuration of refineries. The number of hydrogenation units is increasing. [0003] Hydrocracking technology is a kind of hydrogenation technology, and it is one of the important means to process heavy distillate oil into clean products. Hydrocracking technology generally uses vacuum distillate oil or similar distillate oil as raw material to produce high-quality Naphtha, aviation kerosene and diesel oil, while hydrocracking tail oil is also a high-quality raw material for steam cracking to ethylene and isomerization dewa...

AI Technical Summary

Problems solved by technology

However, during the start-up process, since there is no normal hydrogenation reaction, there is no source of heat for the device to heat up, and other equipment generally cannot reach the required temperature. Therefore, a heating furnace needs to be installed during the start-up process.

The heating furnace is a high-temperature and high-pressure equipment in the hydrogenation unit, and the equipment investment is very large, and the heating furnace is only used during the start-up process, and the utilization rate of the device is low, and the heating furnace tube is one of the important sources of increasing the pressure drop of the high-pressure system