SU124050A2 - Method for selective two-stage stepwise countercurrent catalytic cracking of heavy oil distillates in a fluidized bed of powdered catalyst - Google Patents

Description

The described method of selective two-stage graded-countercurrent catalytic cracking of heavy petroleum distillates in a fluidized bed of powdered catalyst as compared with the known method by no. St. No. 112676 provides a higher yield of light products and accelerates the process.

The peculiarity of the described method is that the light cracking of primary raw materials is carried out in the zone with partially deactivated pulverized catalyst coming from the deep cracking zone of secondary raw materials, and the deep cracking of secondary raw materials, for example, heavy catalytic gas oil from the light cracking stage, is carried out over freshly regenerated catalyst entering this zone from a step-countercurrent regenerator.

The catalyst activity and the temperature regime in the zone of easy cracking of the primary raw material are maintained by parallel feeding this zone with a hot freshly regenerated catalyst.

The drawing shows the technological scheme for the implementation of a selective two-stage step-countercurrent catalytic cracking.

The feedstock is heated to the required temperature in the coils of the regenerator 1 and enters zone 2 of the reactor 3 to the lower section. The vapors rise up in contact with the catalyst. The top plate of the reactor 3 enters the coked catalyst from the deep cracking zone 4 through the overflow pipe, and the regenerated catalyst from the regenerator / in the quantity required for support No. 124050 enters through the pneumatic channel.

zhan of the set temperature condition. The catalyst passes a selective cracking zone 2 and a stripping zone, for which, along a flow pipe, it is directed to the upper section of the regenerator.

Secondary feedstock — heavy catalytic gas oil of the first light cracking stage — is fed to the lower section of the reactor 3.

The fractionation of the catalytic cracking products of each stage of the selective processing of heavy feedstock is carried out in separate distillation and condensation devices, but with the general system of co-fractionation of gases from all stages of catalytic processing.

Regulation of the temperature and activity of the catalyst in zone 3 of light catalytic cracking of the primary raw material (which is the 1st stage of raw material processing and the fifth stage of using the catalyst) is planned to be carried out by an additional parallel supply of a relatively small amount of freshly regenerated catalyst to this zone. This method of "bypassing part of the catalyst past deep cracking zone 2 (I-stage of the process) creates greater flexibility in controlling the temperature in the light cracking section and the activity of the catalyst in a wide range.

The effectiveness of the two-stage selective stepwise countercurrent catalytic cracking according to the described scheme significantly increases the yield of fractions of light products (liquid motor fuels.

Subject and reference

Claims (2)

1. A method for selective two-stage stepwise countercurrent catalytic cracking of heavy oil distillates in a fluidized bed and a powder-like catalyst, performed by the author. St. No. 112676 in one general-reactive regeneration unit, characterized in that, in order to increase the yield of light products and the process speed, light cracking of the primary raw material is carried out in the zone with partially deactivated dust-like catalyst coming from the deep cracking zone of the secondary raw material, and deep the cracking of secondary raw materials, for example, heavy catalytic gas oil from a light cracking stage, is conducted over a freshly regenerated catalyst entering this zone from a stepwise countercurrent regenerator. 2. Acceptance of the method according to claim 1, characterized in that the catalyst activity and the temperature regime in the zone of easy cracking of the primary raw material are maintained by parallel feeding this zone with a hot freshly regenerated catalyst.