TWI548732B - A method for producing catalytic cracking of propylene - Google Patents

Description

Method for producing catalytic cracking of propylene

The present invention relates to a process for catalytic cracking, and more particularly to a process for the production of propylene via a catalytic cracking reaction of a heavy feedstock.

Heavy oil catalytic cracking is an important method for the preparation of small molecular olefins such as ethylene, propylene and butene. Industrially used heavy oil catalytic cracking processes for the production of light olefins include catalytic cracking techniques for maximum production of propylene and catalytic pyrolysis techniques for the maximum production of ethylene using either a single riser reactor or a single riser reactor. The reactor structure of the combined fluidized bed is combined with a dedicated catalyst to carry out the reaction at a higher temperature. The above two methods can produce low-carbon olefins such as propylene and ethylene, but the yields of helium and coke are relatively high, and the propylene yield is difficult to further increase.

CN1140608C (i.e., US Pat. No. 6,059,958, A) discloses a method for cooling a regenerated catalyst by cooling a partially regenerated catalyst, a part of the cooled regenerated catalyst and an uncooled high-temperature regenerated catalyst being mixed in a pre-lifting section of the riser, and a relatively low temperature mixed catalyst. The reaction is then contacted with the hydrocarbon oil while another portion of the cooled regenerated catalyst is returned to the regenerator to regulate the regeneration temperature. This method does not involve increasing the yield of propylene.

CN1081222C (i.e., US 6,495,028 B1) discloses a catalytic conversion process for reducing the olefin content of liquefied gases and gasoline. The method proposes that the preheated hydrocarbon oil raw material enters the bottom of the riser and contacts the catalyst in a composite reactor composed of a single riser or a single riser and a fluidized bed, and the reacted hydrocarbon The stream flows up to the middle of the riser or the top of the riser to contact and react with the cooled catalyst, and the reactant stream is subjected to subsequent separation by a settler outflow device to obtain a product. After the high-temperature charred regeneration, the reacted catalyst is divided into two parts, one part enters the bottom of the riser, and the other part is cooled to enter the middle of the riser or the top of the riser, but this method is not conducive to the production of propylene and other small molecular olefins.

CN1428402A discloses a catalytic cracking combined process comprising the following steps: cooling 10 to 80% by weight of a regenerated catalyst into a circulating fluidized bed reactor to contact and react with a gasoline feedstock, and the reacted catalyst enters a circulating fluidized bed reactor. The stripping zone is stripped; 40-90% by weight of the stripped catalyst is returned to the reaction zone for recycling, and the remainder is sent to the pre-lift section of the heavy oil riser before mixing with the uncooled high-temperature regenerated catalyst and then with the heavy hydrocarbons. Oil contact reaction. The method has a low propylene yield, and no method for increasing propylene production and reducing helium is proposed.

CN1177020C discloses a method and device for upgrading a poor quality gasoline. The method proposes that the regenerated catalyst is cooled to 300 ° C -500 ° C and then sent to the stripping section and mixed with the catalyst to be regenerated for countercurrent contact reaction with inferior gasoline, reducing the olefin content and sulfur content in the gasoline, and improving the gasoline RON, but not involving Increased production of propylene.

CN101074392A discloses a method for producing propylene and high quality gasoline and diesel using two-stage catalytic cracking, using a two-stage riser, using a catalyst rich in shape-selective molecular sieves, with heavy petroleum hydrocarbons or hydrocarbon-rich Various animal and vegetable oils are reacted as raw materials. However, the method has low propylene yield and low heavy oil conversion ability.

The technical problem to be solved by the present invention is to provide a catalytic cracking method for producing propylene which can improve propylene yield and low helium selectivity, in view of the deficiencies of the existing catalytic cracking process for producing propylene.

The present invention provides a catalytic cracking process for producing propylene comprising: (1) introducing a heavy feedstock and a first catalytic cracking catalyst into a first riser reactor for catalytic cracking reaction, separation via a riser end The device separates the hydrocarbon stream from the carbon deposition catalyst, introduces the hydrocarbon stream into a subsequent product separation system for separation, and directly introduces the carbon deposition catalyst into the stripper for stripping, or first introduces the fluidized bed reactor, and then enters the steam. The stripper is stripped and introduced into the regenerator for regeneration after stripping; the first catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; and (2) introducing the cracked heavy oil into the second riser reaction In contact with a second catalytic cracking catalyst introduced into the second riser reactor, the second catalytic cracking catalyst comprising a shape-selective zeolite having an average pore diameter of less than 0.7 nm; (3) after introduction of cracked heavy oil Introducing light hydrocarbons into the second riser reactor, mixing and reacting with a mixture formed by contacting the cracked heavy oil and the second catalytic cracking catalyst; the light weight Comprising the product obtained by C4 hydrocarbons separation system and / or gasoline fractions; (4) after the second riser reactor hydrocarbon stream with a catalyst reaction primer Into the fluidized bed reactor in series with the second riser reactor to react; (5) after the fluidized bed reactor reaction, the hydrocarbon stream is introduced into the product separation system for separation, and the carbon deposition catalyst is introduced into the stripper Stripped and then introduced into the regenerator for regeneration.

In a specific embodiment, the present invention provides a catalytic cracking process for producing propylene, comprising: (1) introducing a heavy raw material and a first catalytic cracking catalyst into a first riser reactor for catalytic cracking reaction, Wherein, the riser outlet temperature is about 530 ° C, the reaction time is about 3 seconds, the agent to oil ratio is about 10.7 w / w, and the ratio of atomized steam to heavy raw material is about 8 w%; separation by the end of the riser The device separates the hydrocarbon stream from the carbon deposition catalyst, introduces the hydrocarbon stream into a subsequent product separation system for separation, and directly introduces the carbon deposition catalyst into the stripper for stripping, or first introduces the fluidized bed reactor, and then enters the steam. The stripper is stripped and introduced into the regenerator for regeneration after stripping; the first catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; and (2) introducing the cracked heavy oil into the second riser reactor Contacting a second catalytic cracking catalyst introduced into the second riser reactor, the second catalytic cracking catalyst comprising a shape selective zeolite having an average pore diameter of less than 0.7 nm; The second riser catalyst temperature is about 695 ° C, the second riser outlet temperature is about 540 ° C, and the weight ratio of the cracked heavy oil to the heavy raw material is about 5:100. The cracked heavy oil introduction position is the second riser bottom cracking heavy oil riser total The reaction time is about 1.30 seconds, the ratio of atomized steam to cracked heavy oil is about 10 w%, and the ratio of the oil to cracked heavy oil is about 33.3 w/w; (3) after introducing the cracked heavy oil, the gasoline fraction as a light hydrocarbon is introduced. a second riser reactor which is mixed and reacted with a mixture formed by the contact reaction of the cracked heavy oil and the second catalytic cracking catalyst; wherein the reaction time of cracking the heavy oil before contact with the light hydrocarbon is about 0.3 seconds before contact with the light hydrocarbon The cracking heavy oil reaction temperature is about 655 ° C. When the initial contact with the light hydrocarbons, the amount of carbon deposited on the catalyst is about 0.23 w%. The weight ratio of the light hydrocarbon to the heavy raw material is about 12:100. The ratio of the light hydrocarbon to the light hydrocarbon is about 13.9. The w/w light hydrocarbon riser reaction time is about 1.00 seconds. The proportion of atomized water vapor to light hydrocarbons is about 15 w%. The light hydrocarbons include the gasoline fraction obtained by the product separation system; (4) Hydrocarbons after the second riser reactor reaction The fluidized bed reactor with the catalyst stream is introduced to the second riser reactor to a reaction series; wherein the bed temperature of bed weight hourly space velocity of from about 530 ℃ about 10 h ^-1 (5) in a fluidized bed reactor After the reaction, the hydrocarbon stream is introduced into the product separation system for separation, and the reacted coke catalyst is introduced into a stripper for stripping and then introduced into a regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking process for producing propylene, comprising: (1) introducing a heavy feedstock and a first catalytic cracking catalyst into a first riser reactor for catalytic cracking reaction Wherein the riser outlet temperature is about 560 ° C, the reaction time is about 3 seconds, the agent to oil ratio is about 11.7 w/w, and the ratio of atomized steam to heavy feedstock is about 8 w%; The separation device separates the hydrocarbon stream from the carbon deposition catalyst, introduces the hydrocarbon stream into a subsequent product separation system, and directly introduces the carbon deposition catalyst into the stripper for stripping, or first introduces the fluidized bed reactor, and then enters the steam. The stripper is stripped and introduced into the regenerator for regeneration after stripping; the first catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; and (2) introducing the cracked heavy oil into the second riser reactor Contacting a second catalytic cracking catalyst introduced into the second riser reactor, the second catalytic cracking catalyst comprising a shape selective zeolite having an average pore diameter of less than 0.7 nm; The second riser catalyst temperature is about 655 ° C. The second riser outlet temperature is about 540 ° C. The weight ratio of the cracked heavy oil to the heavy raw material is about 5:100. The cracked heavy oil introduction position is the second riser bottom cracking heavy oil riser total The reaction time is about 1.10 seconds, the ratio of atomized water vapor to cracked heavy oil is about 10 w%, and the ratio of agent to oil of cracked heavy oil is about 34.5 w/w; (3) the gasoline fraction which will be light hydrocarbon after introduction of cracked heavy oil And introducing a second riser reactor at the same level as the C4 hydrocarbon, mixing and reacting with the mixture formed by the contact reaction between the cracked heavy oil and the second catalytic cracking catalyst; wherein the reaction time for cracking the heavy oil before contacting with the light hydrocarbon is about The reaction temperature of cracking heavy oil before contact with light hydrocarbons in 0.5 seconds is about 620 ° C. When the initial contact with light hydrocarbons is about 0.16 w% on the catalyst, the reaction time of the light hydrocarbon riser is about 0.60 seconds. The gasoline fraction and heavy raw materials The weight ratio of the fuel to oil ratio of about 12:100 gasoline fraction is about 14.4 w / w. The ratio of atomized water vapor to gasoline fraction is about 10 w%. The weight ratio of C4 fraction to heavy raw material is about 8:100 C4 fraction. The ratio of agent to oil is about 21.6 w/ w atomized water vapor accounts for about 5 w% of the C4 fraction. The light hydrocarbon comprises C4 hydrocarbon and/or gasoline fraction obtained by the product separation system; (4) after reacting the second riser reactor The hydrocarbon stream and the catalyst are introduced into a fluidized bed reactor connected in series with the second riser reactor; wherein the bed temperature is about 550 ° C, the bed weight hourly space velocity is about 6 h ^-1 (5) in the fluidization After the bed reactor reaction, the hydrocarbon stream is introduced into the product separation system for separation, and the reacted soot catalyst is introduced into a stripper for stripping and then introduced into a regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking process for producing propylene, comprising: (1) introducing a heavy feedstock and a first catalytic cracking catalyst into a first riser reactor for catalytic cracking reaction Wherein the riser outlet temperature is about 500 ° C, the reaction time is about 4 seconds, the agent to oil ratio is about 7 w/w, and the ratio of atomized water vapor to heavy feedstock is about 5 w%; The separation device separates the hydrocarbon stream from the carbon deposition catalyst, introduces the hydrocarbon stream into a subsequent product separation system for separation, and directly introduces the carbon deposition catalyst into the stripper for stripping, or first introduces the fluidized bed reactor, and then enters The stripper is stripped and introduced into the regenerator for regeneration after stripping; the first catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; and (2) introducing the cracked heavy oil into the second riser reaction In contact with a second catalytic cracking catalyst introduced into the second riser reactor, the second catalytic cracking catalyst comprising a shape selective zeolite having an average pore diameter of less than 0.7 nm; The second riser catalyst temperature is about 695 ° C, the second riser outlet temperature is about 520 ° C, and the weight ratio of the cracked heavy oil to the heavy feedstock is about 20:100. The cracked heavy oil introduction position is the second riser bottom cracking heavy oil riser total The reaction time is about 0.80 seconds, the ratio of atomized steam to cracked heavy oil is about 5 w%, and the ratio of the oil to the cracked heavy oil is about 8.3 w/w; (3) after introducing the cracked heavy oil, the gasoline fraction as a light hydrocarbon is introduced. a second riser reactor which is mixed and reacted with a mixture formed by the contact reaction of the cracked heavy oil and the second catalytic cracking catalyst; wherein the reaction time of cracking the heavy oil before contact with the light hydrocarbon is about 0.1 second before contact with the light hydrocarbon The cracking heavy oil reaction temperature is about 595 ° C. When the initial contact with the light hydrocarbons, the amount of carbon deposited on the catalyst is about 1.23 w%. The weight ratio of the light hydrocarbon to the heavy raw material is about 6:100. The ratio of the light hydrocarbon to the light hydrocarbon is about 27.7. The w/w light hydrocarbon riser reaction time is about 0.7 seconds. The proportion of atomized water vapor to light hydrocarbons is about 20 w%. The light hydrocarbons include the gasoline fraction obtained by the product separation system; (4) Hydrocarbons after the second riser reactor reaction The fluidized bed reactor and the catalyst is introduced into the second riser reactor to a reaction series; wherein the bed temperature of bed weight hourly space velocity of about 510 ℃ about 12 h ^-1 (5) in a fluidized bed reactor After the reaction, the hydrocarbon stream is introduced into the product separation system for separation, and the reacted coke catalyst is introduced into a stripper for stripping and then introduced into a regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking process for producing propylene, comprising: (1) introducing a heavy feedstock and a first catalytic cracking catalyst into a first riser reactor for catalytic cracking reaction Wherein the riser outlet temperature is about 515 ° C, the reaction time is about 2.5 seconds, the agent to oil ratio is about 14 w/w, and the ratio of atomized water vapor to heavy feedstock is about 10 w%; The separation device separates the hydrocarbon stream from the carbon deposition catalyst, introduces the hydrocarbon stream into a subsequent product separation system for separation, and directly introduces the carbon deposition catalyst into the stripper for stripping, or first introduces the fluidized bed reactor, and then enters The stripper is stripped and introduced into the regenerator for regeneration after stripping; the first catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; and (2) introducing the cracked heavy oil into the second riser reaction And contacting a second catalytic cracking catalyst introduced into the second riser reactor, wherein the second catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; The temperature of the second riser catalyst is about 695 ° C, the outlet temperature of the second riser is about 530 ° C, and the weight ratio of the cracked heavy oil to the heavy raw material is about 10:100. The cracking heavy oil introduction position is the second riser bottom cracking heavy oil riser The total reaction time is about 0.95 seconds. The ratio of atomized water vapor to cracked heavy oil is about 8 w%. The ratio of the oil to the cracked heavy oil is about 16.6 w/w; (3) the gasoline fraction which will be used as the light hydrocarbon after the introduction of the cracked heavy oil. Introducing a second riser reactor, mixing and reacting with a mixture formed by contacting the cracked heavy oil and the second catalytic cracking catalyst; wherein the reaction time of cracking the heavy oil before contact with the light hydrocarbon is about 0.15 seconds and contacting with the light hydrocarbon The pre-cracking heavy oil reaction temperature is about 645 ° C. When the initial contact with the light hydrocarbons, the amount of carbon deposited on the catalyst is about 0.62 w%. The weight ratio of the light hydrocarbon to the heavy raw material is about 15:100. The ratio of the light hydrocarbon to the light hydrocarbon is about 11.1w/w light hydrocarbon riser riser reaction time is about 0.8 seconds. The proportion of atomized water vapor to light hydrocarbons is about 15 w%. The light hydrocarbons include gasoline fractions obtained by the product separation system; (4) Hydrocarbon after reaction in the second riser reactor The fluidized bed reactor with the catalyst stream is introduced to the second riser reactor to a reaction series; wherein the bed temperature of bed weight hourly space velocity of about 520 ℃ about 11 h ^-1 (5) in a fluidized bed reactor After the reaction, the hydrocarbon stream is introduced into the product separation system for separation, and the reacted coke catalyst is introduced into a stripper for stripping and then introduced into a regenerator for regeneration.

In another embodiment, the present invention provides a catalytic cracking process for producing propylene, comprising: (1) introducing a heavy feedstock and a first catalytic cracking catalyst into a first riser reactor for catalytic cracking reaction Wherein the riser outlet temperature is about 570 ° C, the reaction time is about 1.5 seconds, the agent to oil ratio is about 10 w/w, and the ratio of atomized water vapor to heavy feedstock is about 10 w%; The separation device separates the hydrocarbon stream from the carbon deposition catalyst, introduces the hydrocarbon stream into a subsequent product separation system for separation, and directly introduces the carbon deposition catalyst into the stripper for stripping, or first introduces the fluidized bed reactor, and then enters The stripper is stripped and introduced into the regenerator for regeneration; the first catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; and (2) introducing the cracked heavy oil into the second riser reactor Receiving a contact reaction with a second catalytic cracking catalyst introduced into the second riser reactor, the second catalytic cracking catalyst comprising a shape selective zeolite having an average pore diameter of less than 0.7 nm; The second riser catalyst temperature is about 695 ° C, the second riser outlet temperature is about 575 ° C, and the weight ratio of the cracked heavy oil to the heavy feedstock is about 3.5:100. The cracked heavy oil introduction position is the second riser bottom cracking heavy oil riser total The reaction time is about 1.13 seconds, the ratio of atomized water vapor to cracked heavy oil is about 10 w%, and the ratio of the oil to the cracked heavy oil is about 47.5 w/w; (3) after introducing the cracked heavy oil, the gasoline fraction as a light hydrocarbon is introduced. a second riser reactor which is mixed and reacted with a mixture formed by the contact reaction of the cracked heavy oil and the second catalytic cracking catalyst; wherein the reaction time for cracking the heavy oil before contact with the light hydrocarbon is about 0.43 seconds before contact with the light hydrocarbon The cracking heavy oil reaction temperature is about 675 ° C. The initial carbon on the catalyst is about 0.22 w% when the light hydrocarbon is initially contacted, and the weight ratio of the light hydrocarbon to the heavy raw material is about 12:100. The ratio of the light hydrocarbon to the light hydrocarbon is about 13.9. The w/w light hydrocarbon riser reaction time is about 0.7 seconds. The proportion of atomized water vapor to light hydrocarbons is about 15 w%. The light hydrocarbons include the gasoline fraction obtained by the product separation system; (4) Hydrocarbons after two riser reactor reactions The fluidized bed reactor with the catalyst stream is introduced to the second riser reactor to a reaction series; wherein the bed temperature of bed weight hourly space velocity of about 570 ℃ about 7 h ^-1 (5) in a fluidized bed reactor After the reaction, the hydrocarbon stream is introduced into the product separation system for separation, and the reacted coke catalyst is introduced into a stripper for stripping and then introduced into a regenerator for regeneration.

In the above five specific embodiments, the term "about" means a deviation of ±10%, ±8%, ±6%, ±5%, ±4%, ±3%, ±2%, or ±1%.

The present invention also provides an apparatus for the above method for producing propylene by catalytic cracking, the apparatus comprising a first riser reactor, a second riser reactor, a fluidized bed reactor, a stripper, a settler, a product a separation system and a regenerator; wherein the second riser reactor is connected in series with the fluidized bed reactor, the fluidized bed reactor is in communication with the stripper and the settler, the first riser reactor is connected to the settler, and the regenerator is passed through the catalyst The transfer line is respectively connected with the stripper, the first riser reactor and the second riser reactor, the first riser reactor is provided with a heavy raw material inlet, and the second riser reactor is provided with a cracked heavy oil reaction section and cracking At the heavy oil inlet and the light hydrocarbon inlet, the light hydrocarbon inlet is located between the cracked heavy oil inlet and the second riser reactor outlet; the riser between the cracked heavy oil inlet and the light hydrocarbon inlet constitutes a cracked heavy oil reaction section.

The catalytic cracking method for producing propylene provided by the invention is based on a combined reactor composed of a double riser and a fluidized bed, and is optimized by a process scheme, equipped with a suitable catalyst, and selectively converts different feeds, which is high The heavy oil conversion rate and the higher yield of high-value products, without increasing the yield of helium and coke, have higher propylene yield and butene yield, and lower helium and coke selectivity.

The catalytic cracking method for producing propylene provided by the invention introduces the heavy raw material and the first catalytic cracking catalyst into the first riser reactor, and the heavy raw material is contacted with the first catalytic cracking catalyst through the riser. The terminal separation unit separates the hydrocarbon stream from the carbon deposition catalyst, and the hydrocarbon stream is introduced into a subsequent product separation system for separation; the first catalytic cracking catalyst of the carbon deposit is introduced into the stripper or the fluidized bed of the present invention The reactor, preferably introduced into a fluidized bed reactor. The separation device at the end of the riser is used to separate the reacted hydrocarbon stream from the carbon deposition catalyst, which is advantageous for reducing the helium gas yield and suppressing the reconversion of the low carbon olefin (especially propylene) after the formation. The separating device is preferably a quick dividing device, and the existing quick dividing device can be used, and the preferred quick dividing device is a coarse cyclone separator.

The first riser reactor reaction operating conditions include: the reaction temperature (rising tube reactor outlet temperature) is 480-600 ° C, such as 500-570 ° C, such as about 500 ° C, about 515 ° C, about 530 ° C, about 560 ° C and Approximately 570 ° C; the ratio of agent to oil (weight ratio of catalyst to heavy feedstock) is 5-20, such as 7-15, such as about 7, about 10, about 10.7, about 11.7, and about 14; reaction time is 0.50- 10 seconds, for example 1-4 seconds, such as about 1.5 seconds, about 2 seconds, about 2.5 seconds, about 3 seconds, and about 4 seconds; atomized water vapor accounts for 2-50% by weight of the heavy raw material feed, For example, it is 5 to 10% by weight, such as about 5% by weight, about 8% by weight, and about 10% by weight; the reaction pressure is 0.15-0.3 MPa (absolute pressure), for example, 0.2-0.25 MPa ( Absolute pressure).

In the method for producing catalytic cracking of propylene provided by the present invention, the heavy raw material is a heavy hydrocarbon or a hydrocarbon-rich various animal and vegetable oil raw materials selected from the group consisting of petroleum hydrocarbons and mineral oils. And a mixture of one or more of the synthetic oils. Petroleum hydrocarbons are well known to those skilled in the art and may, for example, be vacuum wax oil, atmospheric residue, vacuum wax oil blended partially vacuum residue or other secondary processed hydrocarbon oil. The hydrocarbon oil obtained by the secondary processing is one or more of a coking wax oil, a deasphalted oil, and a furfural refined raffinate oil. The mineral oil is selected from the group consisting of a mixture of one or more of coal liquefied oil, oil sand oil, and shale oil. The synthetic oil is a distillate obtained by F-T synthesis of coal, natural gas or pitch. The hydrocarbon-rich various animal and vegetable oil raw materials such as animal fats and oils and/or vegetable fats and oils.

The heavy raw material of the present invention has an initial boiling point of a normal pressure boiling range higher than 270 ° C or higher, and a 5% distillation point of a normal pressure boiling range is higher than 300 ° C or higher.

In the method for producing catalytic cracking of propylene provided by the present invention, the cracked heavy oil is introduced into the second riser reactor and contacted with the high-temperature regenerated catalyst, and the reaction mixture formed by cracking the heavy oil and the second catalytic cracking catalyst is raised in the second step. The tube reactor flows and reacts. After a period of reaction, it is mixed with the light hydrocarbons introduced into the second riser reactor, and the resulting mixture flows in the second riser reactor and reacts, and finally flows out of the second riser. reactor. The second riser reactor may have one or more cracking heavy oil inlets and/or one or more light hydrocarbon inlets. Where the second riser reactor has two or more cracked heavy oil inlets, these inlets may be at the same level or at different levels. In the second riser reactor Where there are two or more light hydrocarbon inlets, these inlets may be at the same level or at different levels. The light hydrocarbon is introduced at one or more locations between the second riser reactor cracking heavy oil inlet (the highest inlet) and the second riser reactor outlet, and the second riser reactor is splitting the heavy oil inlet (maximum The area before the entrance to the light hydrocarbon inlet (lowest inlet) is also referred to as a cracked heavy oil reaction zone (also referred to as a cracked heavy oil reaction zone) which undergoes a cracking reaction of the cracked heavy oil.

As used herein, the effective length of the second riser reactor refers to the distance from the second riser reactor cracking heavy oil inlet (the highest inlet) to the second riser reactor outlet.

As used herein, the introduction height of a certain light hydrocarbon refers to the distance from the light hydrocarbon inlet of the second riser reactor to the secondary riser reactor cracking heavy oil inlet (the highest inlet).

According to the present invention, preferably, the introduction height of a certain light hydrocarbon is 1-99%, 2-90%, 3-80%, 4-70%, 5-60 of the effective length of the second riser reactor. %, 5-50%, 5-40%, 5-30%, 5-25%, 5-20%, 5-15%, or 5-10%.

In the cracked heavy oil reaction zone, the ratio of the ratio of the agent oil to the cracked heavy oil reaction (the weight ratio of the second catalytic cracking catalyst introduced into the second riser reactor to the cracked heavy oil introduced into the second riser reactor) is 5-50. For example, 8-48 or 20-48, such as about 8.3, about 16.6, about 33.3, about 34.3, and about 47.5.

The cracked heavy oil atomized water vapor comprises from 5 to 15% by weight of the cracked heavy oil feed, such as about 5% by weight, about 8% by weight, and about 10% by weight.

The cracked heavy oil and the heavy raw material introduced into the first riser reactor The weight ratio is from 0.01 to 0.35:1, such as from 0.01 to 0.10:1 and from 0.01 to 0.20:1, such as about 0.035:1, about 0.05:1, about 0.1:1, about 0.2:1.

Reaction time of cracking heavy oil before contact with light hydrocarbons and second catalytic cracking catalyst in second riser reactor (this invention is referred to as reaction time for cracking heavy oil before contact with light hydrocarbons, ie cracking heavy oil in cracking heavy oil The reaction time of the reaction zone is from 0.1 to 1 second, for example from 0.1 to 0.5 second and from 0.2 to 0.5 second, such as about 0.1 second, about 0.15 second, about 0.3 second, about 0.43 second, and about 0.5 second.

The temperature of the second catalytic cracking catalyst introduced into the second riser reactor in contact with the cracked heavy oil is 600-720 ° C, such as 650-700 ° C, such as 655-695 ° C; such as 655 ° C or 695 ° C.

In the second riser reactor, the reaction temperature of the cracked heavy oil before contact with the light hydrocarbon (ie, the reaction temperature of the cracked heavy oil in the cracked heavy oil reaction zone, which is the outlet temperature of the cracked heavy oil reaction zone) is 580-700 ° C, for example 595-675 ° C and 620-650 ° C, such as about 595 ° C, about 620 ° C, about 645 ° C, about 655 ° C, or about 675 ° C.

According to the invention, the cracked heavy oil has an atmospheric distillation range of between 300 and 550 ° C or between 350 and 500 ° C. The cracked heavy oil of the present invention may be a hydrocarbon oil fraction having a distillation range of from 300 to 550 ° C or a narrow fraction thereof, for example, comprising a heavy oil obtained from the product separation system of the present invention, that is, a cracked product entering the product separation system, separating the gas, After gasoline and diesel, most of the liquid product remains.

Introducing the cracked heavy oil into the second riser reactor, first contacting the high temperature regenerated catalyst for reaction, and then reacting the hydrocarbon stream mixture formed by the reaction Contact reaction with light hydrocarbons. On the one hand, the secondary conversion of heavy oil is realized to increase the heavy oil conversion rate of the whole device, and the heavy oil fraction is used to increase the production of propylene; on the other hand, the heavy oil is formed to selectively deposit the catalyst matrix and the macroporous molecular sieve (if included, for example, Y) The pores of the zeolite, which modulate the properties of the catalyst, enhance the catalytic action of the shape-selective zeolite in the catalyst, and inhibit the hydrogen transfer reaction easily induced by the macroporous molecular sieve (Y zeolite) and the catalyst matrix.

The amount of carbon deposited on the second catalytic cracking catalyst leaving the cracked heavy oil reaction zone (ie, the amount of carbon deposited on the catalyst upon initial contact with the light hydrocarbon) is, for example, 0.1 to 1.5% by weight or 0.1 to 0.5% by weight, such as about 0.16 wt%, about 0.22 wt%, about 0.23 wt%, about 0.62 wt%, and about 1.23 wt%, relative to the weight of the catalyst.

The contact reaction of the cracked heavy oil with the high temperature regenerated catalyst reduces the temperature of the catalyst system and provides a highly efficient conversion environment for the subsequent reaction of the olefin-rich gasoline fraction and/or C4 hydrocarbon, thereby optimizing the catalytic reaction process and increasing the selectivity to propylene formation. Suppresses the formation of hernia.

In the method for producing catalytic cracking of propylene provided by the present invention, the light hydrocarbon is introduced into the second riser reactor after the introduction of the cracked heavy oil, and the temperature formed by the cracked heavy oil and the second catalytic cracking catalyst is 580. The reaction is carried out by contacting a hydrocarbon stream mixture at -700 ° C, for example 595-675 ° C and 620-650 ° C, such as about 595 ° C, about 620 ° C, about 645 ° C, about 655 ° C, or about 675 ° C. The ratio of the ratio of the agent to the oil in the second riser reactor (the weight ratio of the second catalytic cracking catalyst introduced into the second riser reactor to the light hydrocarbon introduced into the second riser reactor) is 5-40, such as about 11.1, about 13.9, about 27.7, and about 36, the second riser The temperature of the reactor (refers to the second riser outlet temperature) is 520-580 ° C, such as about 520 ° C, about 530 ° C, about 540 ° C, or about 575 ° C.

As used herein, light hydrocarbon refers to a hydrocarbon material having a final boiling point of not higher than 250 ° C or 220 ° C.

The light hydrocarbons include gasoline fractions and/or C4 hydrocarbons. In a particular embodiment, the light hydrocarbon is a gasoline fraction and/or a C4 hydrocarbon. The reaction operating conditions of the gasoline fraction in the second riser reactor when the light hydrocarbon comprises a gasoline fraction: the ratio of the ratio of the gasoline to the gasoline in the second riser reactor (the catalyst and the gasoline introduced into the second riser reactor) The weight ratio of the fractions is 10-30, such as 11-28 or 15-25, such as about 11.1, about 13.9, about 14.4, and about 27.7; and the reaction time is 0.1-1.5 seconds, such as 0.3-1.0 seconds or 0.3- 0.8 seconds, such as about 0.6 seconds, about 0.7 seconds, about 0.8 seconds, and about 1.0 seconds; the atomized water vapor of gasoline accounts for 5-30% by weight of the gasoline feed, for example 10-20% by weight, such as about 10 weights. %, about 15% by weight, and about 20% by weight. When C4 hydrocarbons are included, the reaction operating conditions of the C4 hydrocarbons: the ratio of the ratio of the solvent to the C4 hydrocarbons operating in the second riser reactor (the weight ratio of the catalyst introduced to the second riser reactor to the C4 hydrocarbons) is 12-40, For example, 17-30, such as about 21.6; the reaction time of the C4 hydrocarbon in the second riser reactor is 0.5-2.0 seconds, such as 0.5-1.5 seconds, such as about 0.6 seconds; the C4 hydrocarbon atomized water vapor accounts for the C4 hydrocarbon feed amount. 1-8 wt%, such as 3-6 wt%, such as about 5% wt%.

The weight ratio of light hydrocarbons to heavy feedstock introduced into the second riser reactor is from 0.05 to 0.5:1, such as from 0.05 to 0.3:1, such as about 0.06:1, about 0.12:1, about 0.15:1, and about 0.20:1.

In the catalytic cracking method provided by the present invention, the hydrocarbon stream and the catalyst after the second riser reactor reaction are introduced into the fluidized bed reactor to carry out the reaction, and the reaction operating conditions of the fluidized bed reactor include: the reaction temperature is 500-580 ° C, for example, 510-570 ° C and 510-560 ° C, such as about 510 ° C, about 520 ° C, about 530 ° C, about 550 ° C, or about 570 ° C; reaction time-space-speed (reaction to fluidized bed) The total feed of hydrocarbons is 1-35 hours ^-1 , for example 3-30 hours ^-1 , such as about 6 hours ^-1 , about 7 hours ^-1 , about 10 hours ^-1 , about 11 hours ^-1 , and for about 12 ^h-1; and the reaction pressure was 0.15-0.3MPa (absolute), for example 0.2-0.25 MPa (absolute pressure), such as about 0.21 MPa (absolute pressure).

In the catalytic cracking process provided by the present invention, the light hydrocarbons introduced into the second riser reactor include or are gasoline fractions and/or C4 hydrocarbons, such as olefin-rich gasoline fractions and/or C4 hydrocarbons. The gasoline fraction includes gasoline produced by the apparatus itself (obtained from the product separation system) and/or gasoline fraction produced by other means. The gasoline fraction produced by other devices may be selected from the group consisting of catalytically cracked naphtha, catalytically cracked stabilized gasoline, cokered gasoline, reduced viscosity pyrolysis gasoline, and a mixture of one or more of the gasoline fractions produced by other refinery or chemical processes. Preferably, a gasoline fraction produced by the apparatus itself is used. The olefin-rich gasoline fraction has an olefin content of from 20 to 95% by weight, such as from 35 to 90% by weight, preferably more than 50% by weight. The gasoline feedstock may be a full-range gasoline fraction having a final boiling point of not more than 204 ° C, for example, a gasoline fraction having a distillation range of 30-204 ° C, or a narrow fraction thereof, for example, a distillation range of 30-140 ° C. The gasoline fraction is preferably a gasoline fraction having a distillation range of 30 to 85 ° C or a narrow fraction thereof.

The weight ratio of the gasoline fraction introduced into the second riser reactor to the heavy feedstock introduced into the first riser reactor is 0.05-0.20:1, for example 0.06-0.15:1 or 0.08-0.15:1, such as about 0.06: 1, about 0.12:1, and about 0.15:1. The gasoline fraction is preferably an olefin-rich gasoline fraction, more preferably an olefin-rich gasoline fraction produced by the apparatus itself.

The C4 hydrocarbons refer to low molecular hydrocarbons present in a gaseous form at normal temperature (eg, 0-20 ° C) and atmospheric pressure (eg, 1 atm) with a C4 fraction, including carbon atoms in the molecule of 4. Alkanes, alkenes and alkynes. It may be a gaseous hydrocarbon product rich in C4 fraction produced by the apparatus itself, or a gaseous hydrocarbon rich in C4 fraction produced by other apparatuses or processes, preferably a C4 fraction produced by the apparatus. The C4 hydrocarbons are preferably olefin-rich C4 fractions wherein the C4 olefin content is greater than 50% by weight, preferably greater than 60% by weight, and most preferably greater than 70% by weight. Preferably, the light hydrocarbon comprises a gasoline fraction, with or without C4 hydrocarbons, and the weight ratio of C4 hydrocarbon to gasoline fraction is 0-2:1, such as 0-1.2:1 or 0-0.8:1, such as about 2: 3. When the light hydrocarbon comprises C4 hydrocarbons, the weight ratio of C4 hydrocarbons to heavy feedstock introduced into the second riser reactor is from 0.05 to 0.3:1, such as from 0.05 to 0.15:1, such as about 0.08:1.

The pre-lifting media described herein may be selected from one or more of water vapor, C1-C4 hydrocarbons or conventional catalytic cracking helium, preferably water vapor and/or olefin-rich C4 cut. The pre-lifting section described herein refers to the work of redirecting the regenerative catalyst from the regenerated catalyst to the vertical upward acceleration along the riser and causing the catalyst to form a relatively evenly distributed flow state (ie, the flat flow) in the radial direction of the riser. Section.

In the catalytic cracking process provided by the present invention, the heavy feedstock and the cracked heavy oil are in the direction from the riser inlet (lowest) to the riser outlet (highest), before, during or after the pre-lift section Introduced.

According to the invention, the bottom of the riser refers to the position near the pre-lift section and after the pre-lift section in the direction from the riser inlet (lowest) to the riser outlet (highest).

In the catalytic cracking process provided by the present invention, the separation unit at the end of the first riser reactor separates the hydrocarbon stream from the carbon deposition catalyst. The hydrocarbon stream is further separated from the catalyst carried therein (as described below) into a subsequent product separation system. The hydrocarbon stream after the fluidized bed reactor reaction is separated into the carried catalyst by a settler and then passed to a subsequent product separation system. In the product separation system, the hydrocarbon stream is separated to obtain cracked gas, pyrolysis gasoline, cracked light oil, and cracked heavy oil. The product separation system can adopt the prior art, and the present invention has no special requirements.

In the catalytic cracking method provided by the present invention, the carbon deposition catalyst separated by the separation device at the end of the first riser reactor can be directly introduced into the stripping system for stripping, or can be introduced into the fluidized bed reactor first, and the fluidized bed. After the catalyst in the reactor is mixed, it is then fed into a stripping system for stripping, preferably after being introduced into the fluidized bed reactor and then entering the stripper for stripping. The cracking catalyst leaving the fluidized bed reactor enters the stripper for stripping, the two catalysts are stripped in the same stripper, the stripped catalyst is introduced into the regenerator for regeneration, and the regenerated catalyst is introduced into the first riser reactor. And the second riser reactor is recycled.

In the catalytic cracking method provided by the invention, stripping steam and stripping The hydrocarbon stream, preferably introduced into the bottom of the fluidized bed reactor, exits the reactor after passing through the fluidized bed, can reduce the partial pressure of the hydrocarbon stream, shorten the residence time of the hydrocarbon stream in the settling section, increase the production of propylene, and reduce Helium, coke yield.

In the catalytic cracking method provided by the present invention, the riser reactor is selected from one or a combination of an equal diameter riser, an equal line speed riser and a variable diameter riser, wherein the first riser reaction The second riser reactor and the second riser reactor may be of the same type or of different types. The fluidized bed reactor is selected from the group consisting of a fixed fluidized bed, a fluidized bed, a bubble bed, a turbulent bed, a fast bed, a transport bed, and a dense bed reactor.

In the catalytic cracking method provided by the present invention, the catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm, that is, the first catalytic cracking catalyst and the second catalytic cracking catalyst both have an average pore diameter of less than 0.7 nm. Shape-selective zeolite. The shape-selective zeolite having an average pore diameter of less than 0.7 nm is selected from the group consisting of ZSM series zeolites, ferrierite, chabazite, ring spar, erionite, zeolite A, zeolite zeolite, turbidite, and physical and/or chemical treatment. A mixture of one or more of the above obtained zeolites. ZSM series zeolites are selected from the group consisting of ZSM-5, ZSM-8, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, ZSP, ZRP zeolite and other similar structures. a mixture of one or more of the zeolites. For a more detailed description of ZSM-5, see USP 3,702,886, which may be HZSM-5 or an elementally modified ZSM-5 zeolite, such as a phosphorus and transition metal modified ZSM-5 zeolite. One or more. ZSM-5 zeolite modified with phosphorus and transition metals is for example modified with phosphorus and iron ZSP zeolite. The ZRP zeolite may be a hydrogen form or a ZRP zeolite modified with an element such as phosphorus and rare earth. See USP 5232675, CN1211470A, CN1611299A for a more detailed description of ZRP.

The shape-selective zeolite catalyst having an average pore diameter of less than 0.7 nm may be a combination of one or more of the catalysts provided by the prior art, and may be commercially available or prepared according to existing methods. The catalyst comprises a zeolite, an inorganic oxide and optionally a clay, for example comprising: 5 to 50% by weight of zeolite, 5 to 95% by weight of inorganic oxide, 0 to 70% by weight of clay, said zeolite comprising an average pore diameter of less than 0.7 nm of shape-selective zeolite, or further comprising optional large-pore zeolite, the shape-selective zeolite having an average pore diameter of less than 0.7 nm accounts for 25-100% by weight of the active component, preferably 50-100% by weight, macroporous The zeolite comprises from 0 to 75% by weight of the active component, preferably from 0 to 50% by weight.

The large pore zeolite is a zeolite having a pore structure of at least 0.7 nm ring opening, such as a Y zeolite, such as a rare earth Y zeolite (REY), a rare earth hydrogen Y zeolite (REHY), an ultrastable Y zeolite (USY) And a mixture of one or two or more of rare earth super stable Y-type zeolite (REUSY), beta zeolite, and L-type zeolite.

The inorganic oxide is used as an adhesive and may be selected from the group consisting of cerium oxide (SiO ₂ ) and/or aluminum oxide (Al ₂ O ₃ ). The clay is used as a substrate, i.e., a carrier, and may be selected from kaolin and/or halloysite.

In the catalytic cracking method provided by the present invention, the shape-selective zeolite catalyst having an average pore diameter of less than 0.7 nm used in the second riser reactor may be the same as or different from the catalyst used in the first riser reactor. Preferred is a first catalytic cracking catalyst and a second catalytic cracking The catalyst is the same catalyst.

In the catalytic cracking method provided by the present invention, the catalytic cracking apparatus used includes at least a reactor portion, a regenerator portion and a product separation system, and preferably the reactor adopts a combined reaction formed by a double riser and a fluidized bed. In a configuration, one of the riser and the fluidized bed reactor is preferably connected in series with the other of the riser in series, and the coaxially connected structure of the riser and the fluidized bed is further coupled with the stripper. Preferably, the coaxial coupling arrangement.

A specific embodiment of the apparatus for catalytically cracking propylene produced by the present invention is shown in FIG. 1 and includes a first riser reactor 1, a second riser reactor 2, a fluidized bed reactor 4, and a stripping 3, a settler 5, a product separation system 6 and a regenerator 7; wherein the riser reactor 2 is coaxially connected in series with the fluidized bed reactor 4, and the fluidized bed reactor 4 is connected to the stripper 3 and the settler 5 to be lifted The tube reactor 1 is connected to the settler 5; the bottom of the riser reactor 2 is provided with a cracked heavy oil inlet and a cracked heavy oil reaction section, and the cracked heavy oil inlet is connected to the cracked heavy oil outlet 34 of the product separation system 6 via a line 36, the riser A light hydrocarbon inlet is provided between the cracked heavy oil inlet of reactor 2 and the outlet of riser reactor 2, the inlet being in communication with light hydrocarbon line 24, said cracked heavy oil reaction section being at the cracking heavy oil inlet and the light hydrocarbon inlet between. The bottom of the stripper 3 is in communication with the regenerator 7 via a catalyst transfer line 8 to be regenerated, the regenerator 7 is in communication with the bottom of the riser reactor 1 via a regenerated catalyst transfer line 9, and the regenerator 7 is upgraded via the regenerated catalyst transfer line 10 The bottom of the tube reactor 2 is connected.

The riser and the fluidized bed reactor are coaxially connected in series, and are lifted The tube outlet preferably includes a low pressure outlet distributor having a pressure drop of less than 10 KPa. The low pressure outlet distributor is for example an arched distributor.

The method provided by the present invention is further illustrated below with reference to the drawings: as shown in Fig. 1, the high-temperature regenerative catalytic cracking catalyst flowing to the reactor system is divided into two, and the first regenerated catalyst delivery line 9 enters the riser reaction. At the bottom of the vessel 1, another stream is passed through the regenerated catalyst delivery line 10 to the bottom of the riser reactor 2. Correspondingly, the two catalysts accelerate the upward flow under the action of the pre-lifting medium introduced by lines 22 and 23, respectively.

The preheated heavy raw material (heavy hydrocarbon or various hydrocarbon-rich animal and vegetable oils) is mixed with a certain amount of atomized water vapor from line 21 via line 20, and then introduced into riser reactor 1. The hydrocarbon stream and the catalyst mixture are separated by a fast separation device (not shown) at the end of the riser 1 to obtain a hydrocarbon stream and a carbon deposition catalyst.

The cracked heavy oil stream from the product separation system 6 of the apparatus is mixed with atomized water vapor from line 38 via line 36 and introduced into the bottom of riser reactor 2 to contact and react with the high temperature regenerated catalyst introduced via line 10, hydrocarbon stream. The mixture with the catalyst flows upward along the riser 2, in the subsequent path, i.e., between the cracked heavy oil inlet and the riser reactor 2 outlet, with light hydrocarbons from line 24 and atomization from line 25. The mixture of water vapor contacts and reacts and continues to ascend. All of the mixture of hydrocarbon stream and catalyst passes through the outlet distributor of the riser 2 (not shown) and enters the fluidized bed reactor 4 to continue the reaction and finally enters the settling zone. The separator 5 performs the separation of the hydrocarbon stream from the catalyst.

All hydrocarbon streams, including the hydrocarbon stream from riser reactor 1 and the hydrocarbon stream from fluidized bed reactor 4, are collected via a settler top cyclone separation system (not shown) and via line 30. Lead out and enter the subsequent product separation system 6.

In product separation system 6, catalytic cracking products are separated into gaseous hydrocarbons (derived from line 31), pyrolysis gasoline (derived from line 32), cracked light oil (derived from line 33), cracked heavy oil (derived from line 34), and cracked. Slurry (extracted by line 35).

The cracked gaseous hydrocarbons from line 31 are subjected to subsequent product separation and refining to provide a polymer grade propylene product and an olefin-rich C4 fraction, wherein the olefin-rich C4 fraction can be returned to riser reactor 2 for conversion to produce propylene.

The pyrolysis gasoline drawn from line 32 can be partially or completely returned to the riser reactor 2 for conversion; the gasoline can be first cut into light and heavy gasoline distillation sections, and the light gasoline fraction or all returned to the riser reactor 2 for conversion.

A portion or all of the cracked heavy oil from line 34 is introduced via line 36 to the bottom of riser reactor 2 for conversion.

The carbon deposition catalyst separated by the quick separation device at the end of the riser reactor 1 is introduced into the fluidized bed reactor 4 and mixed with the catalyst from the riser 2, introduced into the stripper 3 after the reaction, and the stripped steam is introduced through the line 37. In countercurrent contact with the carbonaceous catalyst, the hydrocarbon stream carried by the carbonaceous catalyst is stripped as clean as possible and passed through the fluidized bed reactor 4 to the settler 5, along with other hydrocarbon streams, leading to the settler via line 30. .

The stripped catalyst is sent to the regenerator 7 via the catalyst delivery line 8 to be regenerated to be charred and regenerated. Oxygen-containing gas such as air is introduced into the regeneration via line 26. The regeneration flue gas is led out via line 27. The regenerated catalyst is returned to the riser reactors 1 and 2 via the regenerated catalyst transfer lines 9 and 10, respectively.

In the above-described embodiment, the pre-lifting medium is introduced to the riser 1 and the riser 2 via lines 22 and 23, respectively.

The invention will be further illustrated by the following examples.

The raw material B used in the examples and comparative examples was a normal pressure heavy oil, and the specific properties are shown in Table 1. The catalyst used is a catalyst of the product number MMC-2 produced by Sinopec Catalyst Qilu Branch. The specific properties are shown in Table 2. The catalyst contains a shape-selective zeolite having an average pore diameter of less than 0.7 nm.

Example 1

Example 1 was carried out in a medium-sized apparatus. In the medium-sized apparatus, the first riser reactor has an inner diameter of 16 mm and a length of 3800 mm, the second riser reactor has an inner diameter of 16 mm and a length of 3200 mm, and the second riser reactor outlet is connected. In a fluidized bed reactor, the fluidized bed reactor has an inner diameter of 64 mm and a height of 600 mm. The configuration is shown in Fig. 1, and the test is operated by a refining method.

A high-temperature regenerated catalyst is introduced into the bottom of the riser reactor 1 through the regenerator 7 via the regenerated catalyst transfer line 9, and flows upward under the action of the steam pre-lifting medium; the feedstock B is preheated and mixed with the atomized water vapor. , entering the riser reactor 1 via the feed nozzle, contacting the hot regenerated catalyst for catalytic conversion reaction, and the mixture of the hydrocarbon stream and the catalyst is ascended along the riser reactor 1 to the rapid separation of the end of the riser reactor 1 The apparatus performs gas-solid separation; after separation, the hydrocarbon stream is introduced into the product separation system 6 to separate into gas and liquid products, and the catalyst enters the fluidized bed reactor 4 by gravity.

Another high temperature regenerated catalyst is sent to the bottom of the riser reactor 2 via the regenerated catalyst transfer line 10 and flows upwards under the action of the steam pre-lifting medium, with the cracked heavy oil fraction from the product separation system 6 (the distillation range is 350- 500 ° C) and the atomized water vapor mixture continued to rise after contact with the reaction, and then with the refinery light gasoline fraction from the product separation system 6 introduced through the nozzle at 300 mm above the cracking heavy oil introduction point (distillation range 30-85 ° C The contact reaction, ascending, and then entering the fluidized bed reactor 4 to continue the reaction, and the reacted hydrocarbon stream is separated into the catalyst carried therein by a settler and introduced into the product separation system 6.

The reacted catalyst (the catalyst to be regenerated, including the catalyst from the first riser reactor and the second riser reactor) enters the stripper 3 in communication with the fluidized bed reactor from the bottom of the fluidized bed reactor, After stripping, the regenerator 7 is brought into contact with air for high-temperature scorch regeneration. The regenerated catalyst is returned to the two riser reactors for recycle via the regenerated catalyst transfer line. The stripping water vapor strips the hydrocarbon stream adsorbed on the catalyst to be regenerated, and then enters the settler via the fluidized bed for gas-solid separation. The main operating conditions and results of the experiment are listed in Table 3.

Comparative example 1

The experiment of Comparative Example 1 was carried out in a medium-sized apparatus. The medium-sized unit uses a double riser reactor structure. The inner diameter of the first riser reactor is 16 mm The length is 3800 mm and the second riser reactor has an inner diameter of 14 mm and a length of 3800 mm. Unlike the test apparatus used in Example 1, the second riser reactor outlet was not connected to the fluidized bed reactor, and its basic configuration can be seen in Figure 1 of CN101074392A. The test was carried out in a refining mode, which was basically the same as in Example 1. The main operating conditions and results of the experiment are shown in Table 3.

Example 2

The experiment was carried out in accordance with the method of Example 1, and the refining C4 fraction from the product separation system 6 was added to the second riser to participate in the reaction, and the reaction operating parameters were adjusted. The reaction conditions and reaction results are shown in Table 3.

Example 3

This embodiment is performed on a medium-sized device as shown in FIG. In the medium-sized apparatus of the continuous reaction-regeneration operation, the riser 1 has an inner diameter of 16 mm and a length of 3800 mm, the riser 2 has an inner diameter of 16 mm and a length of 3200 mm, and the riser 2 outlet is connected to the fluidized bed. 3. The fluidized bed 3 has an inner diameter of 64 mm and a height of 600 mm. The raw material is atmospheric heavy oil B, and the catalyst is MMC-2. The first high-temperature regenerated catalyst is introduced into the bottom of the riser reactor 1 from the regenerator 7 via the regenerated catalyst transfer line 9, and flows upward by the action of the steam pre-lifting medium, and then introduced into the raw material of the riser reactor 1 via the line 20. B contacts the reaction, and then enters the settler 5 [C1] to separate the hydrocarbon stream from the catalyst. The separated hydrocarbon stream is introduced into the product separation system 6, and the catalyst enters the fluidized bed reactor 4; The green catalyst is introduced into the bottom of the riser reactor 2 via the regenerated catalyst transfer line 10, flows upwardly under the action of the water vapor pre-lifting tube medium, and the cracked heavy oil from the product separation system 6 introduced into the riser reactor 2 via line 36 ( The distillation range is 300-550 ° C) and the mixture of atomized water vapor is contacted; the cracked light gasoline (distillation range 32-85 ° C) is introduced into the riser reactor 2 from the top of the cracking heavy oil introduction point 300 mm; the reaction mixture Upstream along the riser, through the riser outlet into the fluidized bed reaction connected to the riser, the hydrocarbon stream after the fluidized bed reaction carries a portion of the catalyst into the settler, followed by gas-solid separation via a cyclone system disposed at the top of the settler. The hydrocarbon stream is introduced into the product separation system 6 via line 30 to separate into gaseous and liquid products; the coke-containing catalyst (catalyst to be regenerated) after the fluidized bed reaction flows into the stripper by gravity, and the stripping steam is presented The adsorbed hydrocarbon stream on the regenerated catalyst is then passed through a fluidized bed into a settler for gas-solid separation. The stripped catalyst to be regenerated enters the regenerator via the catalyst delivery line 8 to be regenerated, and is contacted with air for high-temperature scorch regeneration. The regenerated catalyst is recycled.

The main operating conditions and results of this example are listed in Table 4.

Example 4-5

According to Example 1, the conditions of the reaction were adjusted, and the reaction conditions and results are shown in Table 4.

Comparative example 2

According to the method of Example 2, the difference is the cracking light gasoline At the bottom of the riser 2, the cracked heavy oil is introduced into the bottom of the fluidized bed 4, and the refining C4 fraction from the product separation system 6 enters the pre-lift section of the riser 2. The reaction conditions and results are shown in Table 3.

Comparative example 3

The apparatus used is as shown in Example 1, except that light hydrocarbons are introduced at the bottom of the riser reactor 2, and the split heavy oil inlet is one-half the length between the light hydrocarbon inlet and the outlet of the riser 2. The regenerated catalyst introduced into the riser reactor 2 via the catalyst transfer line is reacted with the light hydrocarbon for a period of time, then reacted with the cracked heavy oil introduced into the riser reactor 2, and then introduced into the fluidized bed reactor 4 for reaction.

It can be seen from Table 3 and Table 4 that the method provided by the present invention can increase the yield of propylene and butene, and can also significantly reduce the yield of helium and coke, and the selectivity of helium (ie, helium yield ^* 100 / conversion rate) ) Reduced, heavy oil conversion capacity enhanced, product distribution is more reasonable.

In Tables 1, 3 and 4, w represents the weight

The fresh feed described in Tables 3 and 4 refers to a heavy feedstock, in the present embodiment, the feedstock B. w refers to the weight and the reaction pressure is the settler pressure.

1‧‧‧First riser reactor

2‧‧‧Second riser reactor

3‧‧‧Sketcher

4‧‧‧ Fluidized Bed Reactor

5‧‧‧Settling device

6‧‧‧Product separation system

7‧‧‧ Regenerator

8‧‧‧Catalyst transfer pipeline to be regenerated

9‧‧‧Regenerated catalyst transfer line

10‧‧‧Regenerated catalyst transfer line

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34‧‧‧ cracking heavy oil outlets, pipelines

35‧‧‧ pipeline

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1 is a schematic flow chart of a catalytic cracking method provided by the present invention, wherein 1 is a first riser reactor, 2 is a second riser reactor, 3 is a stripper, 4 is a fluidized bed reactor, and 5 is sedimentation. , 6 is the product separation system 7, 7 is a regenerator, 8 is a catalyst transfer line to be regenerated, 9 and 10 are regenerated catalyst transfer lines; riser reactor 2 is connected in series with fluidized bed reactor 4 via settler 5 and riser reactor 1 Arranged, the fluidized bed reactor 4 is placed in high and low with the stripper 3 and is in communication.

1‧‧‧First riser reactor

2‧‧‧Second riser reactor

3‧‧‧Sketcher

4‧‧‧ Fluidized Bed Reactor

5‧‧‧Settling device

6‧‧‧Product separation system

7‧‧‧ Regenerator

8‧‧‧Catalyst transfer pipeline to be regenerated

9‧‧‧Regenerated catalyst transfer line

10‧‧‧Regenerated catalyst transfer line

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34‧‧‧ cracking heavy oil outlets, pipelines

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Claims (19)

A catalytic cracking process for producing propylene, comprising: (1) introducing a heavy feedstock and a first catalytic cracking catalyst into a first riser reactor via a pre-lifting medium for catalytic cracking reaction via a riser The terminal separation unit separates the hydrocarbon stream from the carbon deposition catalyst, introduces the hydrocarbon stream into a subsequent product separation system for separation, and directly introduces the carbon deposition catalyst into the stripper for stripping, or first introduces the fluidized bed reactor. And then enter the stripper for stripping, and after stripping, introduce the regenerator to regenerate; the first catalytic cracking catalyst comprises a shape-selective zeolite having an average pore diameter of less than 0.7 nm; (2) the pyrolysis is carried out by the action of the pre-lifting medium The heavy oil is introduced into the second riser reactor and is contacted with a second catalytic cracking catalyst introduced into the second riser reactor, the second catalytic cracking catalyst comprising a shape-selective zeolite having an average pore diameter of less than 0.7 nm; (3) After introduction of the cracked heavy oil, the light hydrocarbon is introduced into the second riser reactor, and the mixture formed by the contact reaction between the cracked heavy oil and the second catalytic catalyst Touching the reaction; the light hydrocarbon comprises a C4 hydrocarbon and/or a gasoline fraction obtained from the product separation system; (4) introducing the hydrocarbon stream and the catalyst after the second riser reactor reaction in series with the second riser reactor In the fluidized bed reactor, the reaction is carried out; (5) after the fluidized bed reactor reaction, the hydrocarbon stream is introduced into the product separation system for separation, the carbon deposition catalyst is introduced into the stripper for stripping, and then introduced into the regenerator. regeneration. For example, the catalytic cracking method of claim 1 of the patent scope, wherein The reaction temperature of the heavy raw material in the first riser reactor is 480-600 ° C, the ratio of the agent to the oil is 5-20, the reaction time is 0.50-10 seconds, and the atomized water vapor of the heavy raw material accounts for the heavy raw material feed amount. 2-50% by weight, and the reaction pressure is 0.15-0.3 MPa absolute. The catalytic cracking method according to claim 2, wherein the reaction temperature of the first riser reactor is 500-570 ° C, the ratio of the agent to the oil is 7-15, and the reaction time is 1-4 seconds, and the heavy raw material is The atomized water vapor accounts for 5-10% by weight of the heavy raw material feed, and the reaction pressure is 0.2-0.25 MPa absolute pressure. The catalytic cracking method according to claim 1, wherein the contact time between the cracked heavy oil and the second catalytic cracking catalyst in the second riser reactor is 0.1 to 1 second before the contact with the light hydrocarbon, The ratio of the oil to the cracked heavy oil reaction is 5-50:1, the atomized water vapor of the cracked heavy oil accounts for 5-15% by weight of the feed of the cracked heavy oil; the second catalytic cracking catalyst introduced into the second riser reactor The temperature is 600-720 °C. The catalytic cracking process of claim 4, wherein the contact of the cracked heavy oil with the second catalytic cracking catalyst in the second riser reactor is 0.1 to 0.5 seconds before contact with the light hydrocarbon. The catalytic cracking process of claim 4, wherein the temperature of the second catalytic cracking catalyst introduced into the second riser reactor is 650-700 °C. The catalytic cracking method of claim 4, wherein the ratio of the oil to the cracked heavy oil in the second riser reactor is 20-48. For example, the catalytic cracking method of claim 1 of the patent scope, wherein In the second riser reactor, the reaction temperature for cracking the heavy oil is 580-700 ° C before contact with the light hydrocarbon. The catalytic cracking process of claim 8, wherein the reaction temperature of the cracked heavy oil is 595-675 ° C before contact with the light hydrocarbon. The catalytic cracking process of claim 1, wherein the light hydrocarbon reacts in the second riser reactor at a ratio of from 5 to 40. The catalytic cracking method of claim 1, wherein the light hydrocarbon is a gasoline fraction and/or a C4 hydrocarbon, and when the light hydrocarbon comprises a gasoline fraction, the gasoline fraction is reacted in the second riser reactor. The operating conditions are: the ratio of the agent to the oil is 10-30, the reaction time is 0.1-1.5 seconds, and the amount of atomized water vapor of the gasoline is 5-30% by weight of the gasoline fraction feed; when the light hydrocarbon includes C4 hydrocarbon, The operating conditions for the reaction of the C4 hydrocarbon in the second riser reactor are: a ratio of the agent to the oil of 12 to 40, and a reaction time of 0.50 to 2.0 seconds. The catalytic cracking method of claim 1, wherein the weight ratio of the cracked heavy oil to the heavy raw material is 0.01-0.35:1; and the weight ratio of the light hydrocarbon to the heavy raw material is 0.05-0.5: 1. The catalytic cracking method according to claim 12, wherein the weight ratio of the cracked heavy oil to the heavy raw material is 0.01-0.10:1, and the weight ratio of the light hydrocarbon to the heavy raw material is 0.05-0.3:1. The catalytic cracking method according to claim 1, wherein the fluidized bed reactor has a reaction temperature of 500 to 580 ° C and a weight hourly space velocity of ¹ to 35 hr ^-1 . The catalytic cracking method of claim 1, wherein the carbon catalyst from the first riser reactor is introduced into the fluidized bed The device. The catalytic cracking method of claim 1, wherein the heavy raw material is a heavy hydrocarbon and/or a hydrocarbon-rich various animal and vegetable oil. The catalytic cracking process according to claim 1, wherein the cracked heavy oil is a hydrocarbon fraction having a distillation range of 300 to 550 ° C or a narrow fraction thereof, which is separated by the product separation system. The catalytic cracking method of claim 1, wherein the catalyst comprises 5 to 50% by weight of zeolite, 5 to 95% by weight of inorganic oxide, and 0 to 70% by weight of clay, the zeolite comprising 25 to 100% by weight of the average A shape-selective zeolite having a pore diameter of less than 0.7 nm, and 0 to 75% by weight of a large pore zeolite. An apparatus for producing propylene for catalytic cracking, comprising a first riser reactor (1), a second riser reactor (2), a fluidized bed reactor (4), a stripper (3), a settler (5), a product separation system (6) and a regenerator (7); wherein the second riser reactor (2) is connected in series with the fluidized bed reactor (4), the fluidized bed reactor (4) and the steam The extractor (3) is in communication with the settler (5), the first riser reactor (1) is connected to the settler (5), the settler (5) is connected to the product separation system (6); the second riser is connected The bottom of the reactor (2) is provided with a cracked heavy oil inlet and a cracked heavy oil reaction section, which is separated from the product separation system (6) via a product separation system (6) for transporting the cracked heavy oil line (36). The heavy oil outlet (34) is in communication, and the regenerator (7) passes through the catalyst transfer line (8) to be regenerated, the catalyst transfer line (9) to the first riser reactor (1), and the second riser reactor (2) Catalyst transfer line (10) with stripper (3), first riser reactor (1) and second lift The tube reactor (2) is in communication, and a light hydrocarbon inlet is disposed between the cracked heavy oil inlet of the second riser reactor (2) and the outlet of the second riser reactor (2), and the cracked heavy oil reaction section is in the cracked heavy oil Between the inlet and the light hydrocarbon inlet.