JPH01306497A - Catalytic decomposition of hydrocarbon - Google Patents

Abstract

PURPOSE: To make catalytic cracking of hydrocarbons with a high yield of propylene by supplying gasoline and crude material of hydrocarbons to a long stretching division in a tubular shape, conducting catalytic cracking using a specific catalyst under a high-temp. partial evaporation, separating the catalyst at the other end, making fractional distillation of the flowout object from reactions, and recirculating part of the products from fractional distillation.

CONSTITUTION: A catalyst containing one or more sorts of zeolite is inserted at a temp. T1 from a pipeline 2 at one end of a long stretching division 1 in a tubular shape and positioned vertically and allowed to flow through, and gasoline is inserted from a pipeline 3a at the level C of the previous flow at the crude material inlet level B, and then, a liquid state crude material for hydrocarbons is inserted at a temp T2 lower than T1 from a pipeline 3 at the level B, and partial evaporation of the crude material is made at the temp T3 by means of heat exchange between the catalyst particles and liquid state crude material so that a catalytic cracking of the crude material takes place. The catalyst is separated from the outflow object from reactions using a separation device 4 installed at the other end of the division 1, and the outflow object is subjected to fractional distillation into LPG, gasoline, light petroleum, and heavy petroleum, when part of the heavy petroleum fraction is recirculated to the level A of the division 1 through a pipeline 5 to that effective catalytic cracking of the hydrocarbons will take place.

COPYRIGHT: (C)1989,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is within the framework of catalytic cracking of hydrocarbon feedstocks in the fluid state.

[Prior art and its problems] Currently, the most commonly used method for this purpose is the so-called fluidized bed catalytic cracking method (Fluid Ca
talytlc cracking, or FCC law)
. In this type of process, a hydrocarbon feedstock is vaporized and contacted at high temperature with a cracking catalyst, which is suspended in the feedstock vapor. After the boiling point has been lowered to a certain extent and the desired molecular weight range has been obtained by cracking, the catalyst is separated from the resulting product, stripped, the coke produced is burned and regenerated, and then brought into contact with the feedstock to be cracked. let

Raw materials that can be used are those with a final boiling point of about 400°C, such as gas oil under vacuum, as well as heavier hydrocarbons, such as crude oil and/or petroleum excluding gasoline, and atmospheric distillation. or vacuum distillation residues, and these raw materials are, if necessary, pretreated, e.g.
Treatments such as hydrogen treatment in the presence of cobalt-molybdenum or nickel-molybdenum type catalysts may also be applied. Preferred feedstocks of the present invention will normally contain fractions with boiling points up to 700°C, and may also contain high proportions of asphaltene-based materials, and contain some amount of Conradson carbon, up to 10% or more. You may do so.

Catalysts that can be used in the above devices include aluminosilicate crystal types and certain silica-alumina, magnesia, and silica-zirconium decomposition catalysts.

The applications of catalytic cracking reactions are currently increasing, and the raw materials to be treated are becoming increasingly heavy. And such raw materials become difficult to evaporate. As a result, the part of the raw material that is not evaporated is charged to the reactor regardless of the details.
A large amount of coke will be formed. The resulting disadvantages are, inter alia, a lower yield of vaporizable substances, an increased generation of regeneration gas, an increased air consumption, and an increased catalyst flow rate, resulting in an oversized overall reaction-regeneration apparatus. That's true.

What is important is that a good evaporation of the raw materials can be carried out in the reaction zone. Due to the additional formation of coke, an undesirable quantity of heat is generated, which is therefore advisable to remove.

What governs successful vaporization of the feedstock is the temperature of the mixture of feedstock and catalyst overall, the partial pressure of the hydrocarbon utilized in the reaction zone, and the surrounding technology. As is known, injector type and modification affect the evaporation rate, not the evaporation limit due to thermodynamic issues.

Among the parameters that are thought to affect the evaporation of raw materials, temperature appears to be the key parameter, and increasing the temperature improves evaporation.

The purpose of French Patent No. 2,604,720 is to allow the evaporation of the feedstock to be completed by flowing the feedstock and catalyst upward in a long tubular reaction zone (i.e. the elevator-back riser in FIG. 1). . Generally, in existing methods, the catalyst enters the bottom of the long zone (1) via line (2), and the feedstock is liquid and flows to the long zone (1), i.e. the bottom of the riser, but above the catalyst inlet level. Bell B is entered via at least one conduit (3). The catalyst enters the riser at a temperature T1, generally above 600° C., and flows through the lower part of this riser in a flow ffi D1. The feedstock enters the riser at a temperature T2 and with a flow ffi D2. Mixing of the feedstock and catalyst takes place at the outlet level of the feedstock inlet line (3). Heat exchange occurs between the catalyst and the feedstock, and this heat exchange results in the evaporation of at least a portion of the feedstock. At this time, equilibrium is reached at a temperature T3 higher than T27,
At this level of the riser, the mixture of feedstock and catalyst is
Distributed in D3. There, a decomposition reaction occurs, and this reaction (
Since it is an endothermic reaction, heat is absorbed by this reaction. At the top of the riser or long section (1), the separation of the gaseous reaction effluent from the catalyst particles is carried out, for example by a T-shaped separator (4).

The device control parameter is the temperature T4 (lower than T3) prevailing at the exit of the riser. Constant temperature T
4 (e.g. 520°C) and a constant heat of reaction (
For example, if ΔH), and also if the flow rate is constant,
Eight T is considered to correspond to a constant ΔH. In other words,
This means that if the operator determines T4 and △H, then T
A temperature T3 higher than 4 means a constant value. At this time, if T4 drops for some reason, the temperature T
3 and thereby raise T4 to the value originally selected by the operator, it is necessary to control the supply of heat to the reaction system (typically by modifying the flow rate of the flowing catalyst). In French patent no. 2,604,720, T
3, it is necessary to supply more heat to the system by, for example, increasing the flow rate of the catalyst or raising the temperature of the raw material. But if you do this,
The temperature at the riser outlet also increases, which is not the desired objective. In other words, what is desired is that T4 be determined to a predetermined value (conversion rate is determined) from thermodynamic and kinetic considerations of the decomposition reaction. The method of French patent no.
5), the downstream flow is completely above the raw material injection point (pipe line (
3)) The purpose of this is to inject heat into the system (Q2
).

By injecting the fluid above the raw material injection point, the temperature T3 can be increased, but this is different from what would happen if the fluid was mixed with the raw material and mixed with the raw material. It's the opposite.

The adjustment of this temperature T3 can therefore be achieved by injecting a suitable fluid into at least one line (5), thus making it possible to increase the flow rate of the catalyst or the temperature of the feed without increasing the temperature T4. implement.

As a result, a higher temperature level is obtained in the vicinity of level A, which is suitable for improving the evaporation of the raw material (achievement of temperature T'3, which is higher than temperature T3 and therefore higher than temperature T4).

This method of temperature control by mixing suitable fluids, raw materials, and catalysts is now customarily referred to as "mixing temperature control".
mperature control! )'' or "MTC". This method may be distinguished from conventional methods that do not inject the fluid of interest, conventionally referred to as "no mixing temperature control."

The fluid that allows this adjustment is a suitable gas or fluid. This may be reformate gasoline from a nearby unit, or it may be a suitable gas such as propene. It may also be part of the reaction effluent transferred from the riser (1). Such effluents are generally fractionated into various fractions, as described in the main application. These spills include, among others, gasoline, relatively light petroleum oils (i.e. “light cycle oils”)
il) L, C, O,), relatively heavy petroleum (i.e. “
Heavy cycle oil H
,C,0,)'' and residue (i.e., slurry).

In French Patent No. 2,604,720, at least a portion of gasoline or, preferably, L, C, O,
A portion of or H,C.

0, recirculate a portion. For more details, H, C,
It is preferred to recirculate the O. After all, H, C
If the weight of ,O, is constant (gasoline or gas, C,O
There are fewer molecules in gasoline or gasoline than in C, O, (compared to the equivalent weight of gasoline or gasoline, C, O, etc.), and therefore the riser sizing is sized for gasoline or gasoline.

Furthermore, H,C,0, has the advantage of being evaporable substances, that is, while creating conditions favorable for improving the evaporation of raw materials, This is because it has the advantage of being a substance that will be present once again in the reaction zone and will therefore be subject to once more cracking and thus improve the overall yield of vaporizable material of the total fraction initially fed. be.

H, C, O, (In some cases, C, O.

The recirculation of 2) has the advantage that the recycle material coming from the fractionation zone is suitable. If it is desired to recycle the residue obtained from the bottom of the fractionation column, even if this slurry is processed for refining purposes (clarified oil or “
(Manufacturing of clarif'1edoil" C, O,) This would not be applicable.

Generally, the difference between T3 and T4 is about 2 to 150℃,
More specifically, it is appropriate to select a temperature of 30 to 70°C. This temperature difference mainly depends on the type of raw material.

Preferably, T'3-T3 is about 2
to 30℃, more specifically about 18 to 25℃, and T
In this case, it is preferable to select a temperature range of 20 to 70°C as the difference between T3 and T4.

The recycling ratio of a portion of the reaction effluent is 1 to 1 to feedstock.
00% by volume. If a portion of the H, C, O, is recycled, the recycled portion could preferably be from 10 to 50% by volume, based on the feedstock.

Furthermore, French patent application No. 881100763 of January 21, 1988 (see Figure 2 of the present patent application) discloses that a fluidized or entrainment bed in a substantially vertical tubular long section (1) A catalytic cracking process for hydrocarbon feedstocks is described, in which the catalyst particles are charged via line (2) to the bottom bottom of a long section (1), and the feedstock is passed through at least one line (3). At the bottom of the long section (1) after passing through the wake,
That is, it is charged at level B above the inlet level of the catalyst particles, which are separated from the reaction effluent in the upper part of the long section (1), which in turn in particular contains LPG.
, gasoline, relatively light petroleum 'L,C,O,' and relatively heavy petroleum 'H,C,O,' are fractionated to obtain various fractions.The characteristics of this method are: So,
Gasoline is passed through at least one pipe (3-a) into the long section (1) with a wake above the catalyst particle inlet level and below the feedstock feed level B. Injected into Level C, the gasoline is from 5 to 50% by volume of the feedstock, and on the other hand, triate (eri) is used as a catalyst.
The method is to use a material containing at least one zeolite of the onite group.

It has been found in the present invention that when operating according to the method of French Patent Application No. 88100763 and at the same time according to the method of French Patent Application No. 264,720, on the one hand C.

A synergistic effect occurred in improving the propylene production yield due to O9 and, on the other hand, also improving the overall selectivity.

[Means for solving the problem] The present invention is illustrated in FIG. 3, and is it tubular? It relates to a process for the catalytic cracking of hydrocarbon feedstocks in a fluidized or entrainment bed in a substantially vertical long section (1) (see Figure 3) in the presence of a catalyst comprising at least one zeolite of the trifoliite group. The feedstock and catalyst particles flow from bottom to top (Figure 3) or from top to bottom, and the contact particles are at a temperature Tl, generally above 600°C, through at least one long pipe (2). Area (1)
The liquid raw material is charged at one end, and the liquid raw material is at a temperature T lower than the temperature T1.
2, the material is charged to the long zone (1) via at least one line (3) leading to the long zone (1) at level B downstream of the contact particle charge level, and partially drains the raw material. The evaporation
The heat exchange between the catalyst particles and the liquid raw material takes place at a temperature T3 higher than the temperature T2, and then the catalyst particles rise to a temperature T3.
At the other end of said long zone (1), where a lower temperature T4 prevails, it is separated from the reaction effluent, which is then separated from the reaction effluent, in particular LPG, gasoline fraction, light petroleum fraction (i.e. L.C. O.) fractions, relatively heavy petroleum fractions (i.e. H, C, O,) and generally residues are collected.

A feature of this process is the use of a catalyst comprising a zeolite of the erl, onlte family; another feature is that (a) the H,C on the one hand;

A fluid comprising at least a portion of the O9 fraction passes through at least one line (5) at level A downstream of level B;
is recirculated within the long zone, so as to obtain a temperature T'3 higher than the temperature T3 at L Novel A, and at temperature T3 to enable the evaporation of all or most of the raw material that would not have been evaporated at level B. , and (b) on the other hand, gasoline;
Recycled gasoline comprising at least a portion of a fraction selected from the group consisting of, for example, gasoline and LPG (C3 and/or C4 paraffins) is passed through at least one line (3a) to the catalyst particle inlet level. Its long section (
1).

Generally, T3-T4 is 2 to 100℃, and even 2 to 1
00℃ and T'3- T3 is between 2 and 30℃
, preferably between 18 and 25°C, especially T3-
T4Lt30 to 70°C or 20 to 70°C, or in the case of some raw materials, 10 to 45°C or 4 to 30°C
``It's between C.

Generally, the fluid (recirculated to level A) is 1 to 100 vol% (preferably 2 to 10 vol%) of the feedstock, but depending on the feedstock it may be 10 to 50 vol%, and level C. The fraction that is recycled is 5 to 50% of the raw material.
% by volume, preferably from 10 to 30 % by volume.

[Example] The following examples are illustrative of the invention.

The properties of the heavy feedstock proposed to be processed in these examples are as follows.

That is, Specific gravity (20℃) (1,988 Viscosity (60℃) Solid C5t (80℃) 119.8 (L), 9.8
mm 2/5) (100℃) 52.2 (52
, 2+nm 2/s) Conradson% 5. l Na1) 1) II 2 Ni ppm 1,6 v ppm, 2 C% 8B, 9 H% 12.2 N % 0,35 S % 0.21 Basic N% 0.055 Aromatic C% 22.3 Aromatic H% 2,7 Simulated Distillation ('C) 5% 367 10% 399 20% 436 40% 495 60% 575 FBP - In the first series of tests, the catalyst used was:
Conventional ultra-stable zeolite diluted with a matrix that is a silica-rich silica-alumina and kaolin mixture)
USY (30% by weight of zeolite based on the weight of the catalyst).

Other properties of the catalyst Total alumina present 37% by weight Surface area m2/g 110 Rare earth oxides, 6% by weight Na20 0.3% by weight Vanadium 4800 ppI11 Nickel 2800 ppm Iron
The 10200 ppm first test operates conventionally with FCC in the elevator tube (riser) without H,C,0° recirculation and without gasoline injection.

- Injection temperature of catalyst 771°C - Injection temperature of raw material 210°C - Temperature of elevator near pipe (3) - 537°C - Temperature of upper part of elevator: 516°C - C10-6 (C is the flow rate of catalyst , O is the flow rate of heavy feedstock. Therefore, C1
0 is the ratio "catalyst/oil").

In the second test, the same operation as the first test is carried out, and in addition, direct distillation gasoline is injected countercurrently to the feedstock injection.

Therefore, operate according to FIG. Although this direct distillation gasoline is a 50-160°C fraction, it is not olefinic and has the following composition.

Paraffins (wt%) = 58 Olefins (wt%) - 0 Naphthenes (wt%): 29.5 Aromatics (wt%) 12.5 This gasoline contains 2 wt%
The following compounds with 5 carbon atoms are included. The weight of gasoline injected is 20% of the weight of the cracked feedstock. The temperature T3 near the inlet of line (3) is 537°C, and the temperature T4 at the top of the riser is 516°C.

In the third test, operate as in the first test, but in this case according to FIG. 4. The resulting heavy diluent 4096 is therefore recycled via line (5).

Catalyst particles are injected via line (2) at 771°C and feedstock is injected via line (3) at 210°C. Pipeline (3)
The temperature T3 of the riser near the artificial pipe is 537°C.

The temperature T4 at the top of the riser is 516°C.

Temperature T'3 is 556°C.

The fourth test operated according to the second and third tests, while at the same time using the method illustrated in FIG.

In the course of the previous three tests, the operating conditions were therefore as follows: That is, catalyst injection temperature Ti (℃) 771 raw material injection temperature T2 (''C), 210 level B temperature T3 (''C) 537 temperature T4 ('C)
516 In the third and fourth tests, the temperature T'3 of level A of conduit (5) is 556°C. The gasoline injection temperature was 210° C. in the fourth test, and the injection rate was the same as in the second test.

The results obtained in these four tests are shown in the following table.

The yield is expressed in weight % based on fresh raw material in the first and third tests, and expressed in weight % based on fresh raw material 10 injected gasoline in the second and fourth tests.

In the second and fourth tests, the conversion of the injected gasoline is about 56% by weight.

The yield of C4 olefins as well as propylene can be improved by an injection device for light gasoline of the first distillation at the bottom of the elevator onto a very hot catalyst.

In the case of simultaneous gasoline injection and recirculation of H, C, O, (fourth test), the results are not very surprising (especially for propylene, C4 unsaturated hydrocarbons, (and gasoline) has no increase in coke or slurry content, which can be appreciated in large-capacity industrial equipment.

In the second series of tests, the second and fourth tests (tests 2-2 and 4-2) are repeated under the same operating conditions. This time, however, the catalyst used above is used, but it is combined with orthopotite, which is prepared as follows.
) Add the base solids.

The results are shown in the table below. Test 4-2 is consistent with the present invention.

1-2 square main pipe hole is 6.4Xl O-”m (W,
MEIER, H,0LSON Zeolite Structural Style Diagram, 1978), 200 g of potashite with a molar ratio Si02/Al2O3 equal to 8 and containing 9.9% by weight of potassium and 2.8% by weight of tetramethylammonium ions. , in dry air at a flow rate of 31)/h/g for 2 hours,
The cation TMA+ was removed by firing at 550°C.

The resulting material (designated IA) was then mixed with a 2M solution of ammonium nitrate at 100° C. for 4 hours under stirring at a volume ratio of solution to solid dry weight (V/P) equal to 5. Ion exchanged twice.

The obtained solid, designated as IB, contains 2.8% by weight of potash, and its molar ratio S i02 /A
/203 is 8. This solid IB is referred to as Product 1.

The dodecagonal main pores of potashite did not change with each treatment.

The potassium zeolite (Product 1) obtained above contains 2.8 by weight 96 potash, and was subjected to the following operations. In other words, the first cycle is self-steaming at 550°C for 12 hours (preparation of product 2A); the second cycle is continuous 2-cation exchange with NH4NO32M under the conditions described in Example 1 (preparation of product 2B) - Self-steaming at 650°C for 12 hours (preparation of product 2C) - cation exchange with NH4No32M under the conditions described in Example 1 (preparation of product 2D) - 0.23N hydrochloric acid, then 0.36N hydrochloric acid According to 10
Continuous two-acid diet with V/P of 10 at 0°C for 4 hours (product 2E is obtained after the first acid diet, and product 2F is obtained after the second acid diet).

As a result of these treatments, the crystallinity of product 2F always remains excellent, its potassium content is 0.7% by weight, its ratio S i 02 /A /203 is 25, and its water adsorption capacity is 15% (P/P o -0,1). Let solid 2F be product 2.

Next, in a 20 liter container equipped with a stirrer, add 14 liters of water and 600 liters of dried pseudoboehmite gel, commercially available from CONDEA and containing about 75% alumina by weight.
g and 2.5 kg of silica-alumina that has been calcined and ground to an average particle size of 6 microns. 1
60 cII 13 of pure concentrated nitric acid was added to the mixture with stirring, which was then heated for 45 minutes with constant stirring.
Heat to 0°C. Next, 74% of the potassium zeolite prepared above was added.
Add 0g and stir for 15 minutes.

The mixture was then sprayed in an atomizer NIRO at an inlet temperature of 380°C.
Spray at an outlet temperature of 140°C.

The finished solid has a microspherical shape, and its particle size is comparable to that of commercially available fluidized bed cracking catalysts. This includes 20 per dry product.
Contains % by weight of potashite.

Before such solids are used for decomposition, they are generally
16 at 750°C in an atmosphere consisting of 100% water vapor.
Bake for an hour.

This solid is then added to the previously used catalyst, which contains 20% by weight of this solid, or 4% of the potashite prepared above. The catalyst thus determined is according to the invention.

In Test 2 of 2, the conversion rate of the injected gasoline was the same as that of 56-fold fire.

First, to prepare the molar ratio 5i02/A/203 is 25
It is orthorhombicite which is equal to .

(Left below) In Test 4-2, the light gases H2, CI and C2 did not increase, indicating an improvement in the yield of C3-.

[Brief explanation of the drawing]

1 and 2 are flow sheets showing the prior art, and FIG. 3 is a flow sheet showing an embodiment of the present invention. Applicant for the above patents: Institut Français

Claims (1)

[Claims] 1) Catalytic cracking of a hydrocarbon feedstock in a tubular and substantially vertical long section (1) in a fluidized bed or an entrainment bed in the presence of a catalyst comprising at least one zeolite of the trivolite group. A method in which the feedstock and catalyst particles flow from bottom to top or from top to bottom, the catalyst particles being charged at one end of a long section (1) via at least one pipe (2) at a temperature T1. and the liquid feedstock is transferred to the long zone (1) at a temperature T2 lower than the temperature T1 via at least one pipe (3) leading to the long zone (1) at level B downstream of the contact particle charge level. ), partial evaporation of the raw material takes place at a temperature T3 higher than the temperature T2 by heat exchange between the catalyst particles and the liquid raw material, and then the catalyst particles are dominated by a temperature T4 lower than the temperature T3. is separated from the reaction effluent at the other end of said long section (1), which is then separated from the reaction effluent by
Especially LPG, gasoline fractions, light petroleum fractions (i.e. L.C.O.) and heavier petroleum fractions (
That is, H. C. O. ) in which (a) on the one hand the H. C. O. a fluid comprising at least a portion of the fraction is recirculated in a long section at level A downstream of level B via at least one line (5);
At level A, a temperature T'3 higher than temperature T3 is obtained, and at temperature T3 it is possible to evaporate all or most of the raw material that would not have been evaporated at level B, and (
b) on the other hand, via at least one conduit (3a);
downstream of the catalyst particle inlet level and at the raw material inlet level B
A method characterized in that the long zone (1) is charged with gasoline at level C upstream of the gasoline. 2) In the method according to claim 1, T3-T4 is 2
to 150℃, T'3-T3 is 2 to 30
Methods in the range of °C. 3) A method according to claim 1, in which T'3-T3 is in the range from 18 to 25C. 4) A method according to claim 2 or 3, in which the fluid (recirculated at level A) is from 1 to 100% by volume of the feedstock and the gasoline injected at level C is 5 to 50% by volume. 5) A method according to claim 4, wherein the fluid comprises 2 to 10% by volume of the feedstock and the gasoline comprises 10 to 3% by volume of the feedstock.
A method that is 0% by volume. 6) A method according to one of claims 1 to 5, in which the raw materials are injected into the reaction zone at a temperature generally in the range from 80 to 400°C and at a relative pressure from 0.7 to 3.5 bar; The temperature of the regenerated catalyst arriving in this zone is between 600 and 95
A method within the range of 0°C.