SU408960A1 - Method of processing hydrocarbon raw material - Google Patents

Description

I

The invention of ognosigs to the field of processing hydrocarbon raw materials, in particular petroleum distillates, by catalytic cracking in the presence of fine catalysagors.

A known method for processing petroleum fractions by catalytic cracking is that the feedstock enters the flow reactor with a gas suspension stream or into a fluidized bed reactor of a fine catalyst. The resulting products pass through a dust collection system where the reaction products are separated from the catalyst. The products of catalytic cracking are fed to fractionation, and the spent catalyst is removed by stripping to remove adsorbed hydrocarbons and then sent to regeneration. Regeneration is carried out as follows. The spent catalyst from the reactor, after passing through the stripping zone, enters the pressure system of the pneumatic conveying system, and

Yes, it is transported by a portion of the regenerating gas through the distribution grid to the fluidized bed of the regenerator. The rest of the regenerating gas is fed through distribution boxes of the mother-type, located concentrically around the distribution grid. Combustion gases, cleared of dust in the settling zone and additionally in cyclone dust collectors, leave the apparatus. 35-5 O weight,% of air required for regeneration, flows through a distribution grid, which area is 8-20% of the apparatus cross-sectional area. Above the distribution grid, the linear velocities of the gas flow reach 2.5–2.3 m / s, creating an upward flow of the gas suspension in the fluidized bed, contributing to the suction of the regenerating gas from the peripheral part of the layer to the central one. The gas flow velocity, referred to the apparatus cross section above the ducts of 0.2-0.3 M / cejs. The gas inflow from the peripheral annular part to the zone with elevated gas flow velocities contributes to a more uneven distribution of the gas over the apparatus cross section. Extreme irregularity of gas flow distribution entails a deadening of phase contact, a decrease in the residence time of the regenerating gas in the fluidized bed and, as a result, a deterioration in the performance of the process as a whole. In addition, the intensive mixing of fine-grained catalyst in the regenerator reduces the driving force of the process and leads to an uneven residence time of the catalyst in the regenerator and, therefore, to uneven burning of coke from individual catalyst particles. As a result of the described vl & Neither the average catalyst activity in the system decreases, and the overall process performance deteriorates. The depth of regeneration under these conditions is 35–5O% with a residual coke content of 0.5–0.9 wt.% (Average O, 7 wt.%). The coke content at the reactor inlet is approximately 1.13, the average coke content on the catalyst in the reaction zone is 0.915 Bes.%. In order to increase the selectivity of the process and increase the gasoline feed rate, the catalyst is regenerated under flow conditions in the gas suspension flow at the first stage and further under the cross-flow conditions of the regenerating gas at the second stage with separate feeding to each stage. The second stage of regeneration is carried out predominantly in a fluidized bed sectioned along the catalyst path. Conducting oxidative regeneration in two stages makes it possible to sharply reduce the residual coke content on the catalyst and thereby increase the activity and selectivity of the catalyst. The ego is especially conspicuous when using zeolite-containing catalysts. The optimal parameters of two-stage regeneration are: linear gas flow rate 1.0-1 O m / s, temperature 50Q-650 C, catalyst concentration 2Q-350 kg / m in the first stage, and, accordingly, 0.1.5 m / All 530-700 ° С, 35О-60О kg / m - secondly, the process has been repaired. FIG. 1 shows a schematic diagram of the process; in fig. 2 traffic dependence of gasoline alchod on the average content of coke on the catalyst. Freshly regenerated catalyst from regenerator 1 through pressure stand 2 enters mixing unit 3 and further into reactor 4, where it contacts with feed or a mixture of fresh and secondary raw materials or only secondary raw materials, or two streams separately with primary and secondary raw materials. The reactor can be of the following type: flow through with a gas suspension or with a fluidized bed. The reaction products, after passing through the separation space 5 of the reactor and the dust collection system 6, are transferred to fractionation. The spent catalyst from the reactor is sent to desorber 7, from which, after removal of adsorbed hydrocarbons, flows through the pressure stand 8 to the exhaust catalyst capture node 9 of the spent catalyst pneumatic transport, where it is picked up by the flow of regenerating gas and moves to the straight section of the regenerator 11. partial regeneration of the catalyst to a depth determined by calculation. The partially regenerated (in the first stage) catalyst enters the fluidized bed, where, under cross-current conditions, the second regeneration stage proceeds and its predetermined depth is reached. Next, the catalyst enters the pressure stand of the regenerated catalyst and into the reactor 4. Air at the second stage of regeneration is supplied independently through the junction box 12. It is possible to carry out the second stage of regeneration by separating the catalyst after the first stage into two independent streams. According to this scheme, the catalyst, which has passed the first stage of regeneration, enters the ring fluidized bed at the point opposite to the point of its withdrawal from the regenerator, and, being divided into two streams, moves to the inlet and further to the pressure station to 2. Efficiency ;, the regenerator works under this scheme is the same as under the scheme of the main variant. The separation of the central and peripheral zones according to the proposed method makes it possible to exclude the flow of catalyst from the lower part of the first layer of the central layer and reduce the flow of regenerated gas to the first stage of regeneration. As a result, catalyst carryover away from the regenerator is reduced and erosion of the transport line is reduced. The dependence of the gasoline yield and catalyst selectivity on the average coke content on the catalyst in the reaction zone is illustrated by the following example. Example The test is carried out in a laboratory setup with a reactor equipped with a stirrer. The raw material is heavy vacuum gas oil (fraction 35 O50O s) of Romashka oil, having the following properties: Density J 0.9170 Fractional composition Boiling start, С332 Boils up 50%, ° С447 To №1кш1ает, wt.% 1.5 To boil up, weight .% 93.0 Sulfur content, weight. % 1.78 Sulfurized, vol.% 54.0 Coking ability, wt.% O, 40 Kinematic viscosity, est 35.0 Pour point, C + 4.0 Chemical composition wt.%: Hydrocarbons: caftan-paraffin 47,5 light aromatic 17 , 6 medium aromatic19.1 t aromatherapy jelly12.4 Resin3.4

Table 1 An equilibrium zeolite-containing aluminosilicate catalyst of type AShNTs-3 with an activity index of 50.8 is taken as a catalyst. The sieve composition of the catalyst ranged from 43 to 1000 µm with a predominance of a fraction from 63 to 3OO µm (about 90 wt.%). The raw material is heated to about 1OO C and is pumped into the reactor. Reaction products and raw materials from the reactor enter the condensation system and the receivers, Gas products, the reaction products through gas, i.e. the clock is discharged into the atmosphere. Condensed liquid products accelerate the sweat by the target fractions. The amount of coke formed is determined on the catalyst after stripping. The experiments are carried out on a regenerated catalyst at a temperature of about 500 ° C, a weight feed rate of about 0.80-0.99 hours, with a different duration so that the content of Koicca on the catalyst after the experiment and thus the average coke content the catalyst was different, in table. Figure 1 shows the experimental data on the dependence of gasoline flow rates and catalyst selectivity on the average content of coke on it.

Experimental conditions Temperature, C

Duration, min

E} the EU feed rate, h

The coke content on the catalyst before the experience,

weight.%

The content of coke on the catalyst after (zhyta, wt.%

The average coke content, weight%

497

500 20 10

0.93

0.80

0.99

0.0

Oh oh

0.0

2.2

1.5

.3,2

0.75

1.1

1.6

Material balance, weight. %

Gas Hg «С ,, Petrol, Cj 195 ° C Balance above 195 С Coke,% Loss

Depth of raw material

l

The output of gasoline on the decomposed raw materials, wt.%

Gasoline / gas ratio

Characteristic qualities of gasoline

It follows from the above data that a decrease in the content of residual coke (and therefore the average content of CBX on the catalyst in the zone catalytic cracking) makes it possible to increase the yield of the target product and increase the selectivity of the catalyst.

The dashed lines in FIG. 2 correspond to the average coke content on the catalyst in the reaction zone with residual coke on the regenerated catalyst O, 75 wt.% (Average coke content 1.075 wt.%) And residual coke 0.15 wt.% (Average coke content about 0.5 wt.%) with the same formation of coke in the cracking process. From these data, it follows that reducing the residual coke content from 0.75 to O, 15 wt.% Allows to increase the yield of gasoline from 46 to 52 wt.% On the initial raw material, and the selectivity of the catalyst also increases. In addition, two-stage regeneration excludes the flow of gas from the periphery

eight

Continued tabl, 1

19.5

40.4

32.7

1.0

67.3

63.7

62.9 2.8O

2.57

to the central ascending gas flow, which increases the uniform distribution of gas over the apparatus’s cross section, aligns the residence time of the catalyst particles in the regenerator, significantly

weakens the intra-reactive mixing of fine-grained catalyst, improves the contact of the phases. Egeneriruquiai raai is served in each stage by its own flow.

The proposed method can significantly increase the depth of catalyst regeneration and reduce the content of residual coke on it. The sectioning of the annular zone makes it possible to further increase the depth of regeneration of the catalyst by further reducing the intrareactive mixing of the fine-grained catalyst.

In tab. 2 shows the results of comparing the regeneration depth and residual coke values and expected gasoline yields according to the known and proposed methods.

As can be seen from this table, when the process according to the proposed method is dried, the residual coke on the regenerated catalyst decreases to 0.15 wt.%, And the yield of bean increases to 52.0 wt.%.

The additional sectioning of the annular fluidized bed into four successive sections along the catalyst makes it possible to ensure the content of residual coke on the regenerated catalyst is about 0.1 wt.% And, consequently, increase the yield of gasoline to 52.5 wt.%.

Claims (2)

1. Method for processing hydrocarbon feedstock by catalytic cracking air 6 NorUa Va in the presence of a fine catalyst and oxidative regeneration of the spent catalyst, is due to the fact that, in order to intensify and increase the selectivity of the process and increase the yield of gasoline, the regeneration is carried out in flow conditions at the first stage stage and then in terms of cross-current regenerating gas in the second stage with a separate feed it to each stage. 2. A method according to claim 1, characterized in that the second stage of catalyst regeneration is preferably carried out in a fluidized bed partitioned along the catalyst. Gases 0. 0,61,01,52,0 ipeoHee codepffiofiue th / ica, / aoes f. n