阅读说明：本技术 双反应器双催化剂的催化裂化方法及催化裂化装置 (Catalytic cracking method and catalytic cracking device for double-reactor double-catalyst ) 是由 孙世源 孟凡东 闫鸿飞 张亚西 武立宪 张瑞风 杨鑫 于 2020-07-15 设计创作，主要内容包括：本发明公开了双反应器双催化剂的催化裂化方法及催化裂化装置,涉及石油炼制技术领域。双反应器双催化剂的催化裂化方法,包括如下步骤：将重质油与重质油催化剂在第一反应器中反应得到第一反应产物；将轻烃原料、甲醇和轻烃催化剂在第二反应器中反应得到第二反应产物；将第一反应产物和第二反应产物混合后进行气固分离得到烯烃产品和待生催化剂；轻烃催化剂的温度小于或等于650℃。用于实施上述催化裂化方法的催化裂化装置,有利于增加轻烃裂解的深度,提高低碳烯烃的产率,利用甲醇在反应中的放热有利于节省装置的能耗。(The invention discloses a catalytic cracking method and a catalytic cracking device of a dual-reactor dual-catalyst, and relates to the technical field of petroleum refining. The catalytic cracking method of the dual-reactor dual-catalyst comprises the following steps: reacting heavy oil with a heavy oil catalyst in a first reactor to obtain a first reaction product; reacting a light hydrocarbon raw material, methanol and a light hydrocarbon catalyst in a second reactor to obtain a second reaction product; mixing the first reaction product and the second reaction product, and then carrying out gas-solid separation to obtain an olefin product and a spent catalyst; the temperature of the light hydrocarbon catalyst is less than or equal to 650 ℃. The catalytic cracking device for implementing the catalytic cracking method is beneficial to increasing the cracking depth of light hydrocarbon and improving the yield of low-carbon olefin, and the energy consumption of the device is saved by utilizing the heat release of methanol in the reaction.)

1. A catalytic cracking method of a dual-reactor dual-catalyst is characterized by comprising the following steps:

reacting heavy oil with a heavy oil catalyst in a first reactor to obtain a first reaction product; reacting a light hydrocarbon raw material, methanol and a light hydrocarbon catalyst in a second reactor to obtain a second reaction product; mixing the first reaction product and the second reaction product, and then carrying out gas-solid separation to obtain an olefin product and a spent catalyst;

the temperature of the light hydrocarbon catalyst is less than or equal to 650 ℃.

2. The catalytic cracking method of the dual reactor dual catalyst as claimed in claim 1, further comprising the steps of regenerating the spent catalyst, separating to obtain a regenerated heavy oil catalyst and a regenerated light hydrocarbon catalyst, introducing the regenerated heavy oil catalyst into the first reactor, and introducing the regenerated light hydrocarbon catalyst into the second reactor;

preferably, the temperature of the regenerated light hydrocarbon catalyst after separation is less than or equal to 650 ℃;

preferably, the temperature for regenerating the spent catalyst is 600-800 ℃, more preferably 650-750 ℃;

preferably, the spent catalyst is stripped prior to regeneration.

3. The dual reactor dual catalyst catalytic cracking process of claim 1 or 2, wherein the proportion of methanol in the total feedstock formed by methanol and the light hydrocarbon feedstock is 20-80% by mass; preferably 40 to 60%.

4. The dual reactor dual catalyst catalytic cracking method as claimed in claim 3, wherein the reaction temperature of the second reactor is 530 ℃ to 600 ℃,

preferably, the reaction pressure of the second reactor is 0.1-0.3MPa,

preferably, the ratio of the agent to the oil of the second reactor is 9-30;

preferably, the second reactor is a fluidized bed reactor, and the reaction time of the second reactor is 3-10 seconds;

preferably, the end point of the light hydrocarbon feedstock is in the range of 60 to 200 ℃.

5. The dual reactor dual catalyst catalytic cracking process of claim 4, wherein the light hydrocarbon catalyst is a ZSM series molecular sieve catalyst;

preferably, the ZSM series molecular sieve catalyst has a bulk density of 0.4 to 0.7g/cm³More preferably 0.5 to 0.65g/cm³；

Preferably, the ZSM series molecular sieve catalyst has an average particle size of 20 to 80um, more preferably 40 to 60 um;

preferably, the ZSM series molecular sieve catalyst has 60-100 wt% particles in the size range of 40-60um, more preferably 80-100 wt%;

preferably, the light hydrocarbon catalyst is carried by the lift dry gas into contact with the light hydrocarbon feedstock.

6. The dual reactor dual catalyst catalytic cracking process of claim 1 or 2, wherein the reaction temperature of the first reactor is 480-530 ℃;

preferably, the reaction pressure of the first reactor is 0.1-0.3 MPa;

preferably, the ratio of the agent to the oil in the first reactor is 5-9;

preferably, the first reactor is a riser reactor, and the reaction time of the first reactor is 2-4 s;

preferably, the heavy oil has a hydrogen content of 9.5-12.5% and a carbon residue content of 1-7%.

7. The dual reactor dual catalyst catalytic cracking process of claim 6, wherein the heavy oil catalyst comprises a Y-type molecular sieve catalyst and a ZSM series molecular sieve catalyst, and the proportion of the Y-type molecular sieve catalyst is 70-95% by mass;

preferably, the bulk density of the heavy oil catalyst is from 0.8 to 1.6g/cm³More preferably 0.9 to 1.3g/cm³；

Preferably, the average particle size of the heavy oil catalyst is 80-600um, more preferably 100-200 um;

preferably, the heavy oil catalyst has particles with a particle size of more than 80um making up 60-100 wt%, more preferably 80-100 wt% of the total;

preferably, the heavy oil catalyst is carried into contact with the heavy oil by the lift dry gas.

8. A catalytic cracking apparatus for implementing the catalytic cracking method of the dual reactor dual catalyst as claimed in any one of claims 1 to 7, which comprises a first reactor for carrying out heavy oil reaction, a second reactor for carrying out light hydrocarbon raw material reaction and a settler for carrying out gas-solid separation on reaction products; the first reactor is provided with a heavy oil feed port and a heavy oil catalyst feed port, and the second reactor is provided with a light hydrocarbon raw material inlet, a methanol raw material inlet and a light hydrocarbon catalyst feed port; and the discharge holes of the first reactor and the second reactor are communicated with the feed inlet of the settler.

9. The catalytic cracking apparatus of claim 8, further comprising a regenerator for regenerating spent catalyst and a particle separator for separating regenerated catalyst; the solid discharge port of the settler is communicated with the regenerator, and the discharge port of the regenerator is communicated with the feed port of the particle separator; the particle separator is provided with a first discharge hole and a second discharge hole, the first discharge hole is communicated with the heavy oil catalyst feed inlet of the first reactor, and the second discharge hole is communicated with the light hydrocarbon catalyst feed inlet of the second reactor.

10. The catalytic cracking apparatus of claim 9, wherein the settler comprises a gas-solid separation section from top to bottom and a stripping section for stripping solids after gas-solid separation, the stripping section extending into the regenerator;

the bottom of strip section is connected with the discharging pipe, the bottom of discharging pipe extends to the cavity bottom of regenerator, be provided with regenerator cyclone in the cavity of regenerator, regenerator cyclone's bottom discharge gate extends to regenerator's cavity bottom, just regenerator cyclone's bottom discharge gate is higher than the bottom of discharging pipe.

Technical Field

The invention relates to the technical field of petroleum refining, in particular to a catalytic cracking method and a catalytic cracking device of a double-reactor double-catalyst.

Background

At present, a catalytic cracking unit produces 70% of gasoline for vehicles and 30% of diesel oil for vehicles. Under the large background of the transformation from 'fuel type' to 'chemical type' of Chinese oil refining enterprises, the catalytic cracking device is taken as one of the most important sources of profit of the oil refining enterprises, and bears the responsibility of continuously making profits for the oil refining enterprises, so that the catalytic cracking process needs to be technically upgraded to adapt to new market conditions. The technical upgrading of the catalytic cracking process mainly has two directions, one is to produce low-carbon olefin mainly containing propylene, and the other is to produce aromatic hydrocarbon mainly containing BTX. The method for producing the low-carbon olefin by catalytic cracking by using the heavy oil and the light hydrocarbon as the raw materials has good market application value and is an important profit source for oil refining enterprises.

Cracking of heavy oil macromolecules requires a larger catalyst pore size, while cracking of light oil macromolecules requires a smaller catalyst pore size. For the same catalyst, it is difficult to achieve the above properties simultaneously, and this is often considered. In order to make up for the defect that the same catalyst cannot give consideration to multiple performances, the current method is to use two catalysts, such as a mixture of USY and ZSM series catalysts, and to enhance the secondary reaction of small molecules by adding the ZSM series catalysts so as to increase the yield of low-carbon olefins.

However, the existing dual catalyst system still has the problem of low yield of low-carbon olefins due to the high difficulty of light hydrocarbon cracking.

Disclosure of Invention

The invention aims to provide a catalytic cracking method of a double-reactor double-catalyst, aiming at improving the cracking degree of light hydrocarbon and increasing the yield of low-carbon olefin.

Another objective of the present invention is to provide a catalytic cracking apparatus, which is beneficial to increase the cracking degree of light hydrocarbons and increase the yield of low-carbon olefins.

The technical problem to be solved by the invention is realized by adopting the following technical scheme.

The invention provides a catalytic cracking method of a double-reactor double-catalyst, which comprises the following steps:

reacting heavy oil with a heavy oil catalyst in a first reactor to obtain a first reaction product; reacting a light hydrocarbon raw material, methanol and a light hydrocarbon catalyst in a second reactor to obtain a second reaction product; mixing the first reaction product and the second reaction product, and then carrying out gas-solid separation to obtain an olefin product and a spent catalyst;

the temperature of the light hydrocarbon catalyst is less than or equal to 650 ℃.

The invention also provides a catalytic cracking device for implementing the catalytic cracking method of the double-reactor double-catalyst, which comprises a first reactor for heavy oil reaction, a second reactor for light hydrocarbon raw material reaction and a settler for gas-solid separation of reaction products; the first reactor is provided with a heavy oil feed port and a heavy oil catalyst feed port, and the second reactor is provided with a light hydrocarbon raw material inlet, a methanol raw material inlet and a light hydrocarbon catalyst feed port; the discharge ports of the first reactor and the second reactor are communicated with the feed port of the settler.

The embodiment of the invention provides a catalytic cracking method of a double-reactor double-catalyst, which has the beneficial effects that: heavy oil and light hydrocarbon raw materials are respectively subjected to catalytic cracking under the catalytic action of a heavy oil catalyst and a light hydrocarbon catalyst, and an olefin product and a spent catalyst are obtained after a product of the catalytic cracking is separated.

The inventor creatively introduces the methanol into the second reactor for the reaction of the light hydrocarbon raw material, and the methanol is in contact reaction with the light hydrocarbon catalyst with lower temperature, and has two advantages: (1) with reactive coupling. The methanol conversion is carried out to generate the low-carbon olefin, the methanol conversion reaction which is easy to carry out can drive the light hydrocarbon cracking reaction which is not suitable to carry out, the difficulty of the light hydrocarbon cracking reaction is reduced, and the yield of the low-carbon olefin is further improved. (2) With coupling in energy. The light hydrocarbon cracking reaction is a strong heat absorption reaction, the heat released by methanol conversion and the heat absorbed by light hydrocarbon cracking are mutually offset, a heat collector is not needed for heat removal, a high temperature can be kept in the fluidized bed reactor at the same time, the high temperature is favorable for the cracking reaction, the light hydrocarbon cracking depth can be improved, and more low-carbon olefins are produced.

The embodiment of the invention also provides a catalytic cracking device for implementing the catalytic cracking method, which is characterized in that heavy oil is reacted in the first reactor, methanol is introduced into the reaction, light hydrocarbon raw materials are reacted in the second reactor, and the product after the reaction is subjected to gas-solid separation through a settler to obtain olefin products and spent catalyst. The method is favorable for increasing the cracking depth of light hydrocarbon and improving the yield of low-carbon olefin, and the energy consumption of the device is favorably saved by utilizing the heat release of the methanol in the reaction.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a catalytic cracking unit provided in an embodiment of the present invention;

FIG. 2 is a catalytic cracking apparatus according to comparative example 1 of the present invention;

FIG. 3 shows a catalytic cracking apparatus according to comparative example 2 of the present invention.

Icon: 100-a catalytic cracking unit; 001-heavy oil feed port; 002-regenerating inclined pipes; a 003-light hydrocarbon raw material inlet; 004-methanol raw material import; 005-lifting dry gas; 006-regenerative chute; 007-regenerant line; 008-lifting dry gas; 009-regenerant ramps; 110-a first reactor; 120-a second reactor; 130-a settler; 131-gas-solid separation section; 132-a stripping section; 133-settler cyclone; 134-a gas collecting chamber; 135-a discharge pipe; 136-a reaction product line; 140-a regenerator; 141-a regenerator cyclone; 143-regenerator heat exchanger; 150-particle separator.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The following is a detailed description of the catalytic cracking method and catalytic cracking apparatus of the dual reactor dual catalyst provided in the embodiments of the present invention.

The embodiment of the invention provides a catalytic cracking method of a double-reactor double-catalyst, which comprises the following steps: heavy oil and light hydrocarbon raw materials are respectively reacted, and then products formed by the reaction are subjected to gas-solid separation to obtain olefin products and spent catalysts.

S1 reaction of heavy oil

The heavy oil and a heavy oil catalyst react in a first reactor to obtain a first reaction product, and the heavy oil catalyst is carried by the lifted dry gas to contact with the heavy oil to generate low-carbon olefins such as ethylene, propylene and the like through catalytic cracking.

In order to further improve the yield of the low-carbon olefin, the inventor optimizes the operation parameters of the first reactor. The reaction temperature of the first reactor is 480-530 ℃, the reaction pressure is 0.1-0.3MPa, and the catalyst-oil ratio of the first reactor is 5-9. Wherein, the catalyst-oil ratio refers to the weight ratio of the catalyst and the heavy oil.

Furthermore, the first reactor is a riser reactor, the reaction time of the first reactor is 2-4s, the hydrogen content of the heavy oil is 9.5-12.5%, and the carbon residue content is 1-7%.

The composition of the heavy oil catalyst is further optimized by the inventor so as to improve the rate and the cracking depth of the catalytic cracking. The heavy oil catalyst comprises a Y-type molecular sieve catalyst and a ZSM series molecular sieve catalyst, wherein the proportion of the Y-type molecular sieve catalyst is 70-95% (accounting for the total weight of the heavy oil catalyst) in terms of mass fraction, and the ZSM series molecular sieve catalyst is added in a small amount, so that the yield of olefin is further improved.

Further, the bulk density of the heavy oil catalyst is 0.8 to 1.6g/cm³Preferably 0.9 to 1.3g/cm³(ii) a The average particle size of the heavy oil catalyst is 80-600um, preferably 100-200 um; the particles with the particle size of more than 80 mu m of the heavy oil catalyst account for 60 to 100 wt% of the total amount, preferably 80 to 100 wt%. The inventor further optimizes the bulk density, the average particle size and the proportion of large-particle catalyst of the heavy oil catalyst, so that the heavy oil catalyst and the heavy oil are better contacted, and the catalytic effect is improved.

S2, light hydrocarbon reaction

Reacting a light hydrocarbon raw material, methanol and a light hydrocarbon catalyst in a second reactor to obtain a second reaction product; the temperature of the light hydrocarbon catalyst is less than or equal to 650 ℃, and the light hydrocarbon catalyst is carried by the lifting dry gas to contact with the light hydrocarbon raw material. The inventor creatively introduces the methanol into the second reactor for the reaction of the light hydrocarbon raw material, and the methanol is in contact reaction with the light hydrocarbon catalyst with lower temperature, and has two advantages: (1) with reactive coupling. The methanol conversion is carried out to generate the low-carbon olefin, the methanol conversion reaction which is easy to carry out can drive the light hydrocarbon cracking reaction which is not suitable to carry out, the difficulty of the light hydrocarbon cracking reaction is reduced, and the yield of the low-carbon olefin is further improved. (2) With coupling in energy. The light hydrocarbon cracking reaction is a strong heat absorption reaction, the heat released by methanol conversion and the heat absorbed by light hydrocarbon cracking are mutually offset, a heat collector is not needed for heat removal, a high temperature can be kept in the fluidized bed reactor at the same time, the high temperature is favorable for the cracking reaction, the light hydrocarbon cracking depth can be improved, and more low-carbon olefins are produced.

It is necessary to supplement that the light hydrocarbon catalyst is generally from the regenerator, the temperature of the light hydrocarbon catalyst is generally high, the inventor creatively separates the light hydrocarbon catalyst before the light hydrocarbon catalyst is introduced into the second reactor to cool the catalyst, the catalyst is prevented from contacting methanol due to overhigh temperature to generate low-value carbon monoxide and hydrogen instead of producing low-carbon olefin, and simultaneously, huge heat energy released by methanol cracking needs a huge heat extractor to take away excessive heat.

Further, the mass fraction of the methanol in the total raw material formed by the methanol and the light hydrocarbon raw material is 20-80%; preferably 40 to 60%. The amount of the methanol is controlled within the range, reaction coupling and energy coupling can be realized to the greatest extent, and the yield of the low-carbon olefin is remarkably improved.

To increase the cracking depth of the light hydrocarbon feedstock, the inventors optimized the operating parameters of the second reactor. The reaction temperature of the second reactor is 530-600 ℃, the reaction pressure is 0.1-0.3MPa, and the catalyst-oil ratio is 9-30; the second reactor is a fluidized bed reactor, and the reaction time of the second reactor is 3-10 seconds; the final distilling point of light hydrocarbon raw material is 60-200 deg.C.

Further, the light hydrocarbon catalyst is ZSM series molecular sieve catalyst, the ZSM series molecular sieve catalyst is more suitable for light hydrocarbon cracking, and the bulk density of the ZSM series molecular sieve catalyst is 0.4-0.7g/cm³Preferably 0.5 to 0.65g/cm³(ii) a The average particle size of the ZSM series molecular sieve catalyst is 20-80nm, preferably 40-60 nm; the ZSM series molecular sieve catalyst has particles in the particle size range of 30-50um in an amount of 60-100 wt%, preferably 80-100 wt%. The inventor further optimizes the bulk density, the average particle size and the particle size range of the light hydrocarbon catalyst, so that the heavy oil catalyst and the heavy oil are better contacted, and the catalytic effect is improved.

S3, separation and regeneration

And mixing the first reaction product and the second reaction product, and then carrying out gas-solid separation to obtain an olefin product and a spent catalyst. In some embodiments, the method further comprises regenerating the spent catalyst, separating the regenerated catalyst to obtain a regenerated heavy oil catalyst and a regenerated light hydrocarbon catalyst, introducing the regenerated heavy oil catalyst into the first reactor, and introducing the regenerated light hydrocarbon catalyst into the second reactor. The catalyst is recycled through the regeneration and separation of the catalyst, and the temperature of the regenerated light hydrocarbon catalyst after the separation is generally less than or equal to 650 ℃, so that the over-cracking of methanol caused by the overhigh temperature of the catalyst is prevented.

Specifically, the temperature for regenerating the spent catalyst is 600-800 ℃, preferably 650-750 ℃; the spent catalyst is stripped prior to regeneration. The catalyst regeneration process can be referred to the description of the prior art, and will not be described in detail herein.

It should be added that the catalyst separation process after regeneration in the embodiment of the present application is performed by using a particle separator, which is only named functionally, and it may be an existing device, a device which can perform screening according to particle size or density, and its specific structure is not limited. Alternatively, device separation in combination with manual separation may be employed in other embodiments.

Referring to fig. 1, an embodiment of the present invention further provides a catalytic cracking apparatus 100 for implementing the catalytic cracking method of the dual-reactor dual-catalyst, including a first reactor 110 for performing a heavy oil reaction, a second reactor 120 for performing a light hydrocarbon feedstock reaction, and a settler 130 for performing a gas-solid separation on reaction products; the first reactor 110 is provided with a heavy oil feed port 001 and a heavy oil catalyst feed port (not shown), and the second reactor 120 is provided with a light hydrocarbon raw material inlet 003, a methanol raw material inlet 004 and a light hydrocarbon catalyst feed port (not shown); the discharge ports of the first reactor 110 and the second reactor 120 communicate with the feed port of the settler 130.

Specifically, the heavy oil feed inlet 001 corresponds to a joint between a heavy oil delivery line and the first reactor 110, the light hydrocarbon raw material inlet 003 corresponds to a joint between a light hydrocarbon raw material delivery line and the second reactor 120, and the methanol raw material inlet 004 corresponds to a joint between a methanol raw material delivery line and the second reactor 120.

In some embodiments, the catalytic cracking apparatus 100 further comprises a regenerator 140 for regenerating spent catalyst and a particle separator 150 for separating regenerated catalyst; the solid discharge port of the settler 130 is communicated with the regenerator 140, and the discharge port of the regenerator 140 is communicated with the feed port of the particle separator 150; the particle separator 150 has a first discharge port and a second discharge port (not shown), the first discharge port is communicated with the heavy oil catalyst feed port of the first reactor 110, and the second discharge port is communicated with the light hydrocarbon catalyst feed port of the second reactor 120. The regenerated catalyst regenerated by the regenerator 140 is separated by the particle separator 150 and then returned to the first reactor 110 and the second reactor 120, respectively.

It should be added that the regenerator 140 and the particle separator 150 are conventional devices, and the structure and operation thereof will not be described in detail herein. A regenerator heat exchanger 143 is also connected to the regenerator 140 for supplying heat to the regenerator 140.

Specifically, the settler 130 comprises a gas-solid separation section 131 and a stripping section 132 for stripping the solids after the gas-solid separation from top to bottom, and the stripping section 132 extends into the regenerator 140; a precipitator cyclone separator 133 is arranged in the cavity of the gas-solid separation section 131, a gas collection chamber 134 is arranged at the top of the gas-solid separation section 131, a gas outlet at the top of the gas-solid separation section 131 is communicated with a gas inlet of the gas collection chamber 134, and the separated gas product is collected in the gas collection chamber 134 and introduced into the next process through a reaction product pipeline 136. The settler cyclone 133 works in combination with a top cyclone and a coarse cyclone and is capable of adequately separating the gaseous products from the catalyst.

Further, the bottom of the stripping section 132 is connected with a discharge pipe 135, the bottom of the discharge pipe 135 extends to the bottom of the cavity of the regenerator 140, a regenerator cyclone 141 is arranged in the cavity of the regenerator 140, a bottom discharge port of the regenerator cyclone 141 extends to the bottom of the cavity of the regenerator 140, and a bottom discharge port of the regenerator cyclone 141 is higher than the bottom of the discharge pipe 135.

The operating principle of the catalytic cracking unit 100 is as follows: heavy oil enters the first reactor 110 from a heavy oil feed inlet 001 through a heavy oil raw material feed pipeline and contacts with a catalyst carried by lifted dry gas 005 to generate a catalytic cracking reaction, a reaction product and the catalyst enter the settler 130 together, the separation of the reaction product and a spent catalyst is realized through the settler cyclone 133, the spent catalyst enters the regenerator 140 through a dipleg after being stripped through a stripping section 132, a regenerated catalyst enters the regenerating agent pipeline 007 through a regeneration inclined pipe 006, the spent catalyst is carried by the lifted dry gas 008 to enter the particle separator 150, a heavier catalyst in the regenerating agent enters the bottom of the first reactor 110 through a regenerating agent inclined pipe 009, a lighter regenerated catalyst and the lifted dry gas 008 enter the second reactor 120 together and contact with light hydrocarbon and methanol to generate a reaction, the reaction product and the spent catalyst enter the settler 130, the separation of the reaction product and the spent catalyst is realized through the settler cyclone 133, the reaction product enters the plenum 134 and then enters the next unit of operation through a reaction product line 136.

The features and properties of the present invention are described in further detail below with reference to examples.