CN114195612A

CN114195612A - Method and device for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon

Info

Publication number: CN114195612A
Application number: CN202110942951.0A
Authority: CN
Inventors: 石宝珍; 李荻; 郭江伟
Original assignee: Qingdao Jingrun Petrochemical Design & Research Institute Co ltd
Current assignee: Qingdao Jingrun Petrochemical Design & Research Institute Co ltd
Priority date: 2020-09-02
Filing date: 2021-08-17
Publication date: 2022-03-18
Also published as: WO2022048440A1

Abstract

The invention relates to a method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, belonging to the technical field of catalytic conversion of petroleum hydrocarbon. The invention provides a method for preparing propylene and ethylene by catalytic conversion, which is characterized in that the temperature is gradually increased, the temperature gradient of two stages is increased, the weight hourly space velocity is independently controlled, a reactor (R10) is divided into two sections or two sections which are connected in series up and down, the two sections or two sections comprise a lower riser reaction zone (R17) and an upper fast fluidized bed reaction zone (R18), and reaction raw materials (R12) are subjected to macromolecular catalytic cracking reaction and micromolecular catalytic cracking reaction in sequence according to molecular structures, so that the staged conversion from macromolecules to propylene and ethylene in the reaction process is realized. The invention reduces the yield of low-value target products such as coke and dry gas on the premise of lower energy consumption; the yield of propylene and ethylene which are high-value target products is improved.

Description

Method and device for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon

Technical Field

The invention belongs to the technical field of petroleum hydrocarbon catalytic conversion, and particularly relates to a method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon.

Background

Propylene is one of the most important petrochemical feedstocks. 70% of the propylene is produced from petroleum hydrocarbons by the tubular furnace cracking process, and the other 30% of the propylene is provided by the catalytic cracking process. By taking the operation and design experience of the conventional heavy oil catalytic cracking reaction-regeneration system as a reference, researchers at home and abroad develop a series of process technologies for producing propylene by heavy oil catalytic cracking.

The petroleum university in china (east china) developed the TMP technology based on the two-stage riser catalytic cracking technology. The technology takes heavy oil as a raw material, utilizes the process characteristics of sectional reaction, catalyst relay and large catalyst-to-oil ratio of a two-section riser catalytic cracking process, performs optimized combination of feeding modes aiming at reaction materials with different properties, and controls the reaction conditions suitable for different materials so as to achieve the purpose of improving the yield of propylene;

the DCC technology which uses heavy oil as a raw material and propylene as a target product is developed by China petrochemical engineering scientific research institute in the last 90 th century. The technology adopts a riser and turbulent fluidized bed layer series reactor, and propylene and ethylene are catalytically prepared from heavy oil under the gas-solid fluidization condition of weight hourly space velocity 4(1/H) -6 (1/H). The reinforced catalytic cracking technology (DCC-PLUS) adopting a novel combined reactor system is developed by the stone institute on the basis of the DCC process, the technology is the same as the DCC process in that a riser reactor and a fluidized bed reactor are adopted, and the difference is that the DCC-PLUS process is additionally provided with a light gasoline and a C4 refining riser, and the light gasoline and the material flow after the reaction of C4 are introduced into the fluidized bed reactor. The DCC or DCC-PLUS divides the raw oil reaction into a riser and a fluidized bed layer reaction; however, DCC and DCC-PLUS control the reaction temperature of the fluidized bed zone through the regenerated catalyst volume entering the raw oil riser reaction zone, i.e. the whole reaction process is controlled according to the conditions of the fluidized bed catalytic cracking reaction zone, so that the catalytic cracking conditions of the riser reaction zone, i.e. the heavy oil reaction zone are inevitably deviated from the ideal raw oil catalytic cracking reaction conditions, especially the thermal reaction is increased; in addition, the airspeed of the bed reaction zone of the fluidized bed with fixed raw material amount can only be controlled by the change of the material level of the catalyst in the bed of the fluidized bed; due to the requirements of catalyst carrying and gas-solid separation, a dilute phase space is arranged between a fluidized bed layer reaction zone and a gas-solid separator, a large amount of catalyst is still carried when oil gas leaves the fluidized bed layer, the residence time of the oil gas leaving the fluidized bed layer to the gas-solid separator is more than 20 seconds, the carrying of the catalyst above the catalyst material level and the residence time of the oil gas inevitably cause further side reaction stop when the fluidized bed layer is adopted for reaction, the propylene is further thermally cracked, the product distribution and the propylene selectivity are influenced, the reaction is difficult to terminate in time, the catalytic cracking reaction is inevitably limited, the thermal reaction is increased, the propylene selectivity is greatly reduced, and the dry gas and coke yield is higher.

The prior art focuses on producing propylene and is divided into two types, wherein the first type is a riser and fluidized bed series type reaction, and the second type is a double-riser parallel type reaction. Researchers believe that propylene in the heavy oil catalytic cracking reaction process is indirectly generated by secondary cracking of a gasoline fraction generated by primary cracking of heavy hydrocarbons, and C5-C8 olefin in the gasoline fraction is a main precursor of the propylene. The prior art has many common features, all of which are operated at higher reaction temperatures, catalyst-to-oil ratios and steam injection levels than conventional FCC processes to increase the cracking severity and propylene selectivity.

Disclosure of Invention

The invention aims to provide a method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, and simultaneously provides a device for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon.

The catalytic cracking reactions of petroleum hydrocarbons, especially heavy oils, appear to be well known and seemingly "almost" although both the regenerated catalyst and the feedstock oil are reacted through a tubular reactor. Due to the complex chemical composition of petroleum hydrocarbon reaction raw materials, complex reaction process, complex change of chemical components of reactants in the reaction process and different product requirements, the actual chemical reactions are different. The improvement of the reaction result by improving the conditions of catalyst activity, space velocity and the like in the reactor and the process conditions of heat distribution, temperature distribution, time distribution and the like in the reaction process is an advanced way of petroleum hydrocarbon catalytic cracking technology. The catalytic conversion of petroleum hydrocarbon to prepare propylene and ethylene is a strong endothermic and coke-forming reaction, and the catalyst, the reactant and the product are obviously changed and complicated in the reaction process; controlling the actual catalyst conditions, temperature conditions, and space velocity conditions in the reactor is extremely important for controlling the chemical reaction process, and different conditions in the reactor actually form different chemical reactions to obtain different products, especially for propylene as a product, a targeted technique is required. The goal of catalytic cracking of petroleum hydrocarbon reaction feedstocks to produce propylene and ethylene is to maximize the possible increase in propylene and ethylene.

The invention adopts the following technical scheme:

a method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon comprises the following reaction processes: heavy component macromolecules are firstly subjected to catalytic cracking conversion under the gas-solid conveying fluidization reaction condition, namely a higher-activity regenerated catalyst environment and a lower temperature condition in a riser reactor to form intermediate molecules mainly comprising C4-C12, and then are subjected to catalytic cracking conversion under the conditions of a gas-solid fast fluidized bed form for improving the catalyst density and reducing the catalyst airspeed, a carbon-containing catalyst environment and high severity to produce propylene and ethylene; the petroleum hydrocarbon catalytic conversion method is carried out in a two-stage reactor which is connected in series up and down, the lower part is a gas-solid conveying bed fluidization form, namely a riser fluidization form, the upper part is a gas-solid fast fluidization form, the reactor is divided into an upper reaction zone and a lower reaction zone by an upper catalyst, namely an upper regenerated catalyst heat providing position (namely an upper catalyst inlet below), namely a riser reaction zone and a fast fluidized bed reaction zone, the lower part of the reactor is a riser reaction zone, or a low-temperature reaction zone, in the riser reaction zone, heavy component macromolecules carry out catalytic cracking reaction to convert to C5-C12 intermediate components under the environment of regenerated catalyst and lower reaction temperature, and intermediate raw materials are provided for preparing propylene and ethylene; the upper part of the reactor is a fast fluidized bed reaction zone or a high-temperature reaction zone, the catalyst entering from an entry point above the reactor, namely the upper catalyst, provides heat to further improve the reaction temperature of the fast fluidized bed reaction zone to form the high-temperature reaction zone, and the intermediate components mainly comprising C5-C12 are subjected to catalytic cracking reaction under the harsher conditions of higher temperature, larger catalyst-oil ratio and lower weight hourly space velocity to convert the petroleum hydrocarbon reaction raw materials into propylene; the selective reaction of the high-boiling-point petroleum hydrocarbon reaction raw material in the upper and lower reactors with two-stage heat supply, two-stage catalyst supply and two-stage control is realized, the gradually-increased reaction mode of the reaction temperature is adapted to the gradually-decreased molecular structure of the molecular weight of reactants and the change of the requirements on the reaction conditions, and the efficiency of preparing propylene and ethylene and the selectivity of target products are improved;

reacting raw materials in a low-temperature riser reaction zone and a high-temperature rapid fluidized bed reaction zone in sequence to realize low-temperature catalytic cracking reaction and high-temperature propylene and ethylene preparation catalytic cracking reaction, respectively feeding the catalyst of a regenerator into the riser reaction zone and the rapid fluidized bed reaction zone, and realizing gradual temperature rise in the reaction process in a graded heat supply mode; the method comprises the following steps of firstly carrying out catalytic cracking reaction on a high-boiling-point heavy component on a petroleum hydrocarbon reaction raw material in a low-temperature reaction zone, preliminarily completing catalytic cracking conversion and decarburization of the heavy component and macromolecules, generating an intermediate component mainly comprising high-olefin gasoline and diesel oil components, enabling the intermediate product and a catalyst to upwards enter a high-temperature reaction zone above a reactor, and continuously providing heat and the catalyst for the zone through another path of catalyst from a regenerator, namely an upper catalyst, so that the temperature of a reactant and the ratio of the gasoline to the gasoline are improved, and realizing the catalytic cracking reaction of the heavy component and the cracking conversion of the intermediate component and the micromolecules; the reaction process comprises the following steps:

(1) the reaction raw materials are atomized by steam and then enter a riser reaction zone at the lower part of the reactor, and carry out catalytic cracking reaction in the environment of lower catalyst introduced from a regenerator through a lower regeneration riser; the riser reaction zone, namely the low-temperature reaction zone, is carried out under the condition favorable for catalytic conversion of heavy components with high boiling points, the catalyst is regenerated, the reaction temperature is 515-620 ℃, the reaction time is 0.5-1.5 s, and when the aim of producing more propylene is fulfilled, the reaction temperature is 515-550 ℃, and the reaction time is 1.0-2.5 s; the actual reaction temperature and the catalyst-to-oil ratio in the riser reaction zone are independently controlled by the amount of the lower catalyst entering the low-temperature reaction zone;

(2) after the reaction raw materials complete low-temperature catalytic cracking reaction in the riser reaction zone, enabling the generated products and the catalyst to flow upwards and enter the rapid fluidized bed reaction zone, reducing the flow velocity of gas and the catalyst in the rapid fluidized bed reaction zone, increasing the density of the catalyst and reducing the weight hourly space velocity of the catalyst; the upper catalyst from the regenerator introduced through the upper regeneration vertical pipe enters a fast fluidized bed reaction zone of the reactor, provides heat for the fast fluidized bed reaction zone, improves the temperature and the catalyst-to-oil ratio, and continues to perform catalytic cracking reaction to generate propylene and ethylene products; the reaction temperature of the fast fluidized bed reaction zone is 530-720 ℃, the reaction time is 0.5-4.0 s, the reaction temperature when propylene is produced in more than one day is 530-580 ℃, the reaction time is 1.0-5.0 s, the absolute pressure of the reaction pressure is 0.20-0.40 MPa, and the actual reaction temperature and the catalyst-oil ratio in the fast fluidized bed reaction zone are controlled by the amount of the catalyst entering the fast fluidized bed reaction zone;

the upper catalyst enters the reactor from an upper catalyst inlet above a reaction temperature control point of a riser reaction zone, or directly enters a rapid fluidized bed reaction zone, or the introduced upper catalyst firstly enters the reactor from an outlet of the riser reaction zone and then is conveyed to the rapid fluidized bed reaction zone, heat is further provided for the rapid fluidized bed reaction zone, the material flow temperature and the solvent-oil ratio are improved, and the catalytic cracking reaction is further carried out;

(3) and the reacted material flow enters a settler for gas-solid separation to obtain a reaction product, and the separated catalyst enters a regenerator for regeneration after steam stripping in a steam stripping section for recycling.

In the specific implementation of the method for preparing propylene and ethylene by catalytic conversion of the petroleum hydrocarbon raw oil, the reaction raw material is preferably one or a mixture of vacuum wax oil, atmospheric residue oil, coker wax oil, deasphalted oil, hydrogenated wax oil (hydrotreated wax oil), hydrogenated residue oil (hydrotreated residue oil) and (straight-run) diesel oil, and the final boiling point is higher than 320 ℃.

In the method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, further, the mixed C4 (also called C4) firstly enters a riser reaction zone below a reaction raw material inlet to react, and then reacts with the reaction raw material in the riser reaction zone and the fast fluidized bed reaction zone; or the C4 enters the reactor above the upper catalyst inlet or directly enters the fast fluidized bed reaction zone for reaction.

In the method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, furthermore, part of the spent catalyst is led out from the stripping section and returned to the reactor, or part of the reacted catalyst is led out from the reactor above the reaction zone of the fast fluidized bed and returned to the reactor from a catalyst return inlet; the spent catalyst or the reacted catalyst returns to the reactor from the catalyst return conveying pipe and the catalyst return inlet, and the catalyst return inlet is arranged at the outlet of the riser reaction zone or at the bottom of the fast fluidized bed reaction zone; the return quantity of the spent catalyst or the catalyst after reaction is controlled by the catalyst inventory and the weight hourly space velocity of the reaction catalyst in the reaction zone of the fast fluidized bed, and the return quantity of the spent catalyst or the catalyst after reaction is controlled by the catalyst return slide valve.

The method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon further comprises the step of enabling liquid light hydrocarbon with the boiling point of more than 90 percent by mass or the final distillation point of less than 360 ℃ to enter a reactor at the outlet of the riser reaction zone or directly enter a fast fluidized bed reaction zone.

The method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon further comprises the steps that a gas-solid pneumatic conveying fluidization form is adopted in a riser reaction zone, and the average gas flow rate is 5.0-20 m/s; the diameter of the fast fluidized bed reaction zone is larger than that of the riser reaction zone, the fast gas-solid fluidized bed condition is adopted, the average gas flow rate is 1.8-5.0 m/s, and the catalyst weight hourly space velocity is 10(1/H) -35 (1/H).

In the method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, furthermore, an upper regeneration zone and a lower regeneration zone, namely a lower regeneration zone and an upper regeneration zone, are arranged below a dilute phase zone of a regenerator of the regenerator, and during specific implementation, the lower regeneration zone is a coke burning tank regeneration zone and the upper regeneration zone is a dense-phase fluidized bed regeneration zone; the lower regeneration zone is a first regeneration zone, the upper regeneration zone is a second regeneration zone, the spent catalyst from the stripping section enters the lower regeneration zone, and the upper regeneration zone is simultaneously provided with a lower catalyst outlet and an upper catalyst outlet; the lower catalyst and the upper catalyst are supplied to the reactor from the upper regeneration zone. Preferably, the lower catalyst temperature is 660-740 ℃, and the carbon content of the catalyst is lower than 0.40%; the temperature of the upper catalyst is 680-730 ℃, and the carbon content of the catalyst is lower than 0.1%. The lower catalyst and the upper catalyst are both regenerated catalysts.

In the method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, an upper regeneration zone and a lower regeneration zone are further arranged below a dilute phase of a regenerator of the regenerator, and in specific implementation, the upper regeneration zone and the lower regeneration zone are both dense-phase fluidized bed regeneration zones; the upper regeneration zone is a first regeneration zone, the lower regeneration zone is a second regeneration zone, the catalyst to be regenerated from the stripping zone enters the upper regeneration zone, the lower regeneration zone is provided with a lower catalyst outlet, the upper regeneration zone is provided with an upper catalyst outlet, the lower catalyst provided to the riser reaction zone through the lower regeneration zone by a lower regeneration vertical pipe (led out from the lower catalyst outlet) is regenerated catalyst, and the upper catalyst provided to the reactor through the upper regeneration vertical pipe (led out from the upper catalyst outlet) is semi-regenerated catalyst with moderate carbon content. During specific implementation, the carbon content and the temperature of the catalysts in the two regeneration zones are adjusted by adjusting the amount of the catalysts in the two regeneration zones of the regenerator and the distribution of the amount of the regenerated oxygen or the amount of air, so that heat is supplied to the high-temperature reaction zone and the catalysts with different carbon contents are supplied to the two reaction zones; when catalysts having different carbon contents are supplied to the reactor, a catalyst having a high carbon content is supplied to the upper pyrolysis reaction zone. Preferably, the lower catalyst temperature is 660-740 ℃, and the carbon content of the catalyst is lower than 0.10%; the temperature of the upper catalyst is 680-730 ℃, and the carbon content of the catalyst is lower than 0.5%.

In the invention, in specific implementation, different regeneration modes are required according to different requirements of different molecular structures of reactants in a reactor on the temperature and the carbon content of the catalyst. When the catalysts entering different reaction zones of the reactor do not need to control the carbon content respectively or do not need to use the catalysts with different carbon contents in different reaction zones for reaction or the temperatures of the catalysts entering different reaction zones are obviously different, the regenerator adopts a conventional coke-burning tank regeneration mode, the lower regeneration zone is a fast fluidized bed, the upper regeneration zone is a dense-phase fluidized bed, and the catalysts are provided for the reactor from the dense-phase fluidized bed;

when the catalysts entering different reaction zones of the reactor need to respectively control the carbon content or need different reaction zones to use catalysts with different carbon contents for reaction, or the temperatures of the catalysts entering different reaction zones are obviously different, the regenerator adopts a regeneration form of an upper and a lower double-phase fluidized bed, the catalyst amount of the two fluidized bed regeneration zones or the entering amount of scorching oxygen or air is adjusted and controlled, so that the catalyst temperature and the carbon content of the two regeneration zones are different, and the catalysts with different carbon contents and temperatures are provided for the reactor from different dense-phase fluidized beds according to the needs;

when the stripped spent catalyst enters the upper regeneration zone, the catalyst in the upper regeneration zone is a 'semi-regenerated catalyst' with moderate carbon, the catalyst in the lower regeneration zone is a regenerated catalyst, the catalyst is provided for the fast fluidized bed reaction zone of the reactor from the upper regeneration zone, and the catalyst is provided for the riser reaction zone from the lower regeneration zone.

The riser reaction zone of the method is mainly used for catalytic conversion of macromolecular heavy components; the fast fluidized bed reaction zone mainly carries out the reaction of cracking to prepare propylene, ethylene and aromatic hydrocarbon.

The invention also provides a device for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, which adopts the scheme that:

a device for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon is provided with a reactor, a regenerator, a settler and a stripping section, a lower regeneration vertical pipe, a lower regeneration slide valve, an upper regeneration vertical pipe, an upper catalyst slide valve, a spent vertical pipe and a spent catalyst slide valve; the regenerator and the settler are arranged in parallel;

the reactor is set into a form of an upper and lower subarea reactor with upper and lower paths of catalyst circulation and twice heat supply, and is divided into two sections or two sections which are connected in series up and down, wherein the two sections or two sections comprise a lifting pipe reaction zone at the lower part and a fast fluidized bed reaction zone at the upper part, the lifting pipe reaction zone is in a gas-solid pneumatic conveying fluidization form with high gas flow velocity, the fast fluidized bed reaction zone is in a fast fluidized bed form with reduced gas flow velocity, and the diameter of the fast fluidized bed reaction zone is larger than that of the lifting pipe reaction zone;

the reactor is provided with two paths of catalyst circulation from a regenerator, heat is supplied to the reactor for the upper and lower times, a riser reaction zone is used for the low-temperature catalytic cracking reaction of the macromolecules of the raw oil, and a fast fluidized bed reaction zone is used for the catalytic cracking reaction of preparing propylene and ethylene at high temperature; a reaction raw material inlet is arranged at the lower part of the riser reaction zone;

a lower catalyst inlet at the lower part of the riser reaction zone is arranged below the reaction raw material inlet, and the lower catalyst inlet is communicated with a lower catalyst outlet of the regenerator through a lower regeneration riser; an upper catalyst inlet is arranged at the bottom of the fast fluidized bed reaction zone or at the outlet of the riser reaction zone and is communicated with the upper catalyst outlet of the regenerator through an upper regeneration riser; a lower regeneration slide valve and an upper catalyst slide valve are respectively arranged on the lower regeneration vertical pipe and the upper regeneration vertical pipe;

the steam stripping section is communicated with the regenerator through a spent catalyst outlet, a spent riser and a spent agent inlet, and a spent catalyst slide valve is arranged on the spent riser.

The above-mentioned apparatus for producing propylene and ethylene by catalytic conversion of petroleum hydrocarbon preferably has a C4 inlet disposed below the inlet of the reaction raw material, or above the inlet of the upper catalyst or at the bottom of the fast fluidized bed reaction zone, or/and a liquid light hydrocarbon inlet disposed above the inlet of the upper catalyst or at the bottom of the fast fluidized bed reaction zone or at the outlet of the riser reaction zone.

In the above apparatus for producing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, preferably, a return catalyst inlet is provided at the lower part of the fast fluidized bed reaction zone or at an outlet of the riser reaction zone above a temperature detection control point of the riser reaction zone, a return catalyst outlet is provided at the stripping section, and the return catalyst inlet is communicated with the return catalyst outlet through a catalyst return conveying pipe, so as to supply a spent catalyst to the fast fluidized bed reaction zone through the stripping section; a catalyst return slide valve is provided on the catalyst return delivery pipe.

In the above apparatus for producing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, preferably, a return catalyst inlet is provided at an outlet of the riser tube reaction zone at the lower part of the fast fluidized bed reaction zone or above a temperature detection control point of the riser tube reaction zone, a return catalyst outlet is provided above the riser tube reaction zone of the reactor, and the return catalyst inlet is communicated with a catalyst return conveying tube, so that the reacted catalyst flows back in the reactor, the reacted catalyst is provided to the fast fluidized bed reaction zone, and the airspeed of the catalyst in the fast fluidized bed reaction zone is controlled; a catalyst return slide valve is provided on the catalyst return delivery pipe.

In the above apparatus for producing propylene and ethylene by catalytic conversion of petroleum hydrocarbon, preferably, an upper regeneration zone and a lower regeneration zone are provided below a dilute phase zone of a regenerator of the regenerator;

the lower catalyst outlet and the upper catalyst outlet are both arranged in the upper regeneration zone, so that the regenerated catalyst is supplied to the reactor through the upper regeneration zone, and the spent agent inlet is arranged in the lower regeneration zone;

or, the upper regeneration zone is a dense-phase fluidized bed regeneration zone, the lower catalyst outlet is arranged in the lower regeneration zone to supply regenerated catalyst, namely lower regenerant, to the riser reaction zone through the lower regeneration zone, the upper catalyst outlet is arranged in the upper regeneration zone to supply catalyst, namely upper catalyst, to the fast fluidized bed reaction zone through the fluidized bed regeneration zone of the upper regeneration zone, and the spent agent inlet is arranged in the upper regeneration zone.

In the invention, the mass ratio of the steam in the low-temperature reaction zone to the reaction raw materials is 5-50%, and the mass ratio of the steam in the high-temperature reaction zone to the reaction raw materials is 15-50%.

During specific implementation, a steam generator can be arranged behind a product outlet of the reaction settler, steam is generated by utilizing heat of high-temperature product material flow, the product material flow is cooled or quenched, and the engineering design unit of the steam generator is mastered.

Effects of the invention

The invention provides a method for preparing propylene and ethylene by catalytic conversion, which is characterized by gradual temperature rise, two-stage temperature gradient and independent control of weight hourly space velocity, based on the principle of catalytic cracking. As is well known in the art, the heavy oil catalytic cracking process can be regarded as a parallel sequential reaction, heavy oil macromolecules are firstly cracked to generate medium molecule (C5-C12) products, the lower cracking temperature can highlight the catalytic cracking reaction, and the temperature suitable for the catalytic cracking reaction is generally 490-530 ℃; part of gasoline and diesel oil is cracked into C3-C4 at 540-580 deg.c. The invention follows the reaction rule and arranges two stages of temperature gradients which are gradually heated in series: a low temperature zone, a high temperature zone; the spent catalyst returns to the reactor, so that the adjustment and control of the catalyst-oil ratio and the catalyst airspeed in the reaction process are realized without influencing the heat balance. The invention reduces the yield of low-value target products such as coke and dry gas on the premise of lower energy consumption; the yield of propylene and ethylene which are high-value target products is improved.

The method of the invention controls the catalyst-oil ratio, the airspeed and the temperature in a reaction process in a grading way, and particularly realizes the reaction along with the reaction, the catalyst-oil ratio and the temperature are gradually increased, the weight hourly space velocity is reduced, and the reaction severity is gradually increased, so that the reaction conditions are adapted to the reaction chemical conditions that the petroleum hydrocarbon molecules are gradually reduced and the required reaction severity is gradually increased in a cracking process of the petroleum hydrocarbon reaction raw materials; the invention also well optimizes the common conversion effect of heavy components and light hydrocarbon raw materials with different properties, avoids over-cracking of small molecular light hydrocarbon, and ensures both the cracking conditions of the heavy components and the light hydrocarbon; the method improves efficiency and increases selectivity of target products.

Drawings

FIG. 1 is a schematic process diagram according to one embodiment of the present invention;

FIG. 2 is a schematic process diagram according to a second embodiment of the present invention;

FIG. 3 is a schematic diagram of a third process according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a fourth process of the present invention;

FIG. 5 is a schematic diagram of a fifth process according to an embodiment of the present invention;

the numbering in the figures illustrates:

an R10 reactor; r11 catalyst lift gas; an R11A catalyst lift gas inlet, an R12 reaction feed, an R12A reaction feed inlet, an R13 feed atomizing steam, an R14A lower catalyst inlet (riser reaction zone catalyst inlet); r15 reaction make-up steam, R15A second reaction make-up steam, R17 riser reaction zone (or low temperature reaction zone), R18 fast fluidized bed reaction zone (or high temperature reaction zone); a catalyst inlet on R24A (fast fluidized bed reaction zone catalyst inlet); R34A returns to the catalyst inlet; r32 liquid light hydrocarbons; R32A liquid light hydrocarbon inlet; R22A C4 inlet; c4 four carbon component petroleum hydrocarbons; an S10 stripping section, S11 stripping means; s12 standing pipe to be generated; an S12A spent catalyst outlet (spent agent outlet); VS12 spent catalyst slide (spent slide); s13 stripping steam; s14 catalyst return conveying pipe; S14A returns to the catalyst outlet; VS14 catalyst return slide valve;

a D10 settler, a D11 settling cyclone; d12 reaction product, D12A settler reaction product outlet;

a G10 regenerator, G11 catalyst regeneration gas, a G11A regeneration gas inlet, a G12 upper regeneration zone (upper catalyst regeneration zone), a G12A spent catalyst inlet, a G13 lower regeneration zone (lower catalyst regeneration zone); g14 lower regeneration vertical pipe (lower catalyst conveying pipe), G14A lower catalyst outlet, G15 regenerator dilute phase region, G16 regeneration cyclone separator, G17 burnt flue gas, G17A flue gas outlet, G18 air, G24 upper regeneration vertical pipe (upper catalyst conveying pipe), G24A upper catalyst outlet (upper catalyst outlet); VG14 lower regeneration spool (lower regeneration catalyst spool), VG24 upper catalyst spool;

TI temperature detection signal, TC temperature control signal and DPC differential pressure control signal.

Detailed Description

The technical solutions of the present invention are described below in the following embodiments and examples, but the scope of the present invention is not limited thereto.

The first implementation mode comprises the following steps:

in the method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon according to the embodiment, the catalytic conversion apparatus shown in fig. 1 is adopted, the reactor R10, the regenerator G10, the settler D10 and the stripping section S10 are arranged, and petroleum hydrocarbon is used as a raw material, and in specific implementation, the petroleum hydrocarbon reaction raw material may be one or a mixture of vacuum wax oil, atmospheric residue oil, wax oil after hydrotreating, residue oil after hydrotreating and crude oil;

the regenerator G10 and the settler D10 are arranged in parallel, the outlet of the reactor R10 is communicated with a settling cyclone D11 in the settler D10, the stripping section S10 is arranged below the settler D10, a stripping component S11 is arranged in the stripping section S10, and stripping steam S13 is introduced into the stripping section S10 to realize the stripping of the catalyst;

the reactor R10 is set into the form of an upper and lower subarea reactor with upper and lower catalyst circulation and twice heat supply, and comprises a lower riser reaction zone R17 and an upper rapid fluidized bed reaction zone R18, the diameter of the rapid fluidized bed reaction zone R18 is larger than that of the riser reaction zone R17, the riser reaction zone R17 is used for low-temperature catalytic cracking reaction, and the rapid fluidized bed reaction zone R18 is used for high-temperature propylene and ethylene cracking reaction; the lower catalyst inlet R14A in the lower portion of the riser reaction zone R17 communicates with the lower catalyst outlet G14A of the regenerator G10 through a lower regeneration standpipe G14, and the upper catalyst inlet R24A in the lower portion of the fast fluidized bed reaction zone R18 communicates with the upper catalyst outlet G24A of said regenerator G10 through an upper regeneration standpipe G24; a reaction raw material inlet R12A is arranged at the lower part of the reactor R10 to introduce a reaction raw material R12 and raw material atomization steam R13, and a catalyst lifting gas inlet R11A is arranged at the bottom of the reactor R10 to introduce catalyst lifting gas R11; the top of the settler D10 is provided with a settler reaction product outlet D12A to lead out a reaction product D12;

the regenerator G10 adopts two zones arranged in series up and down for regeneration, an upper regeneration zone and a lower regeneration zone, namely a lower regeneration zone G13 and an upper regeneration zone G12 are arranged below a dilute phase zone G15 of the regenerator, when the method is concretely implemented, the lower regeneration zone G13 and the upper regeneration zone G12 both adopt a dense-phase fluidized bed form, the lower regeneration zone G13 is a second regeneration zone, the upper regeneration zone G12 is a first regeneration zone, and after the spent catalyst is regenerated in the upper regeneration zone G12, the spent catalyst flows back to enter the lower regeneration zone G13 for continuous regeneration; the lower catalyst outlet G14A is arranged in the lower regeneration zone G13, the upper catalyst outlet G24A is arranged in the upper regeneration zone G12, so that the upper catalyst supplied to the fast fluidized bed reaction zone R18 through the upper regeneration zone G12 is a semi-regenerated catalyst, and the lower catalyst supplied to the riser reaction zone R17 through the lower regeneration zone G13 is a regenerated catalyst; the lower part of the stripping section S10 is communicated with an upper regeneration area G12 of a regenerator G10 through a spent riser S12 from a spent agent inlet G12A, and a spent catalyst slide valve VS12 is arranged on a spent riser S12;

in specific implementation, an upper regeneration zone G12 of the regenerator G10 is communicated with a lower catalyst inlet R14A at the lower part of a riser reaction zone R17 through a lower regeneration standpipe G14 from a lower catalyst outlet G14A, and a lower regeneration slide valve VG14 is arranged on a lower regeneration standpipe G14; the upper regeneration zone G12 is communicated with the upper catalyst inlet R24A at the lower part of the fast fluidized bed reaction zone R18 or at the outlet of the riser reaction zone R17 through an upper regeneration standpipe G24 by an upper catalyst outlet G24A, and an upper catalyst slide valve VG24 is arranged on an upper regeneration standpipe G24; a regenerator cyclone separator G16 is arranged in a regenerator dilute phase zone G15 of the regenerator G10, flue gas G17 after the regenerator is burnt is discharged from a flue gas outlet G17A at the top of the regenerator G10, and catalyst regeneration gas G11 is introduced from a regeneration gas inlet G11A at the bottom of the regenerator G10; air G18 is introduced into regenerator G10 from the lower portion of upper regeneration zone G12;

reaction make-up steam R15 is introduced in the riser reaction zone R17.

In the invention, the catalyst of the regenerator G10 enters a riser reaction zone R17 and a fast fluidized bed reaction zone R18 respectively, and the gradual temperature rise in the reaction process is realized by a graded heat supply mode; the specific implementation process comprises the following steps:

(1) the preheated reaction raw material R12 is atomized by raw material atomization steam R13 and then enters a riser reaction zone R17 at the lower part of a reactor R10, a lower catalyst from a lower regeneration riser G14 and an upper regeneration zone G12 of a regenerator enters a riser reaction zone R17 from a lower catalyst inlet R14A, is conveyed upwards under the action of catalyst lifting gas R11 to be contacted with the raw material, and the reaction raw material R12 is subjected to catalytic cracking conversion under mild conditions in a catalyst environment to form an intermediate product mainly comprising C5-C12; the lower catalyst temperature is preferably 660-740 ℃, and the carbon content of the catalyst is lower than 0.10 percent; the reaction temperature of the riser reaction zone R17 is 515-620 ℃, and the reaction time is 0.5-1.5 s; when the propylene is produced in a high way, the reaction temperature of the riser reaction zone R17 is between 515 and 550 ℃, and the reaction time is between 1.0 and 2.5 seconds; the riser reaction zone R17 adopts a gas-solid pneumatic conveying fluidization form, the average gas flow velocity is 5.0-20 m/s, and the catalyst weight hourly space velocity is 10(1/H) -35 (1/H);

(2) after the reaction raw material R12 finishes the low-temperature catalytic cracking reaction, then the product generated in the riser reaction zone R17 and the catalyst flow upwards together and enter the fast fluidized bed reaction zone R18, the new catalyst, namely the upper catalyst introduced from the regenerator G10 through the upper regeneration riser G24 enters the fast fluidized bed reaction zone R18 and is conveyed to the fast fluidized bed reaction zone R18 by the material flow from the riser reaction zone R17, the new catalyst, namely the upper catalyst further provides heat for the fast fluidized bed reaction zone R18, the material flow temperature and the catalyst-oil ratio are improved, the high-temperature cracking reaction condition with higher severity is formed, the product from the riser reaction zone continues to carry out the combined reaction of catalytic cracking and thermal cracking, and the low-carbon-number small-molecule products such as propylene, ethylene and the like; the preferable temperature of the catalyst is 680-730 ℃, the carbon content of the catalyst is lower than 0.5%, the reaction temperature of the rapid fluidized bed reaction zone R18 is 530-720 ℃, the reaction time is 0.5-4.0 s, when the propylene is produced, the reaction temperature of the rapid fluidized bed reaction zone R18 is 530-580 ℃, the reaction time is 1.0-5.0 s, the absolute pressure of the reaction pressure is 0.20-0.40 MPa, and the actual reaction temperature is controlled by the catalyst entering the rapid fluidized bed reaction zone R18; the diameter of the fast fluidized bed reaction zone R18 is larger than that of the riser reaction zone R17, the fast gas-solid fluidized bed condition is adopted, and the average gas flow speed is 1.8-5.0 m/s;

(3) the reacted material flow enters a settler D10 for gas-solid separation to obtain a reaction product D12, and the reaction product D12 is sent out from a settler reaction product outlet D12A to enter a subsequent treatment part; after being separated by a settling cyclone separator D11, the reacted catalyst is stripped in a stripping section S10 and enters an upper regeneration area G12 of a regenerator G10 through a spent riser S12 and a spent agent inlet G12A, and is regenerated and recycled.

In specific implementation, after the reaction product D12 leaves the catalytic converter shown in FIG. 1, product fractionation is carried out; fractional distillation, etc. are well known to the skilled engineer.

Example 1

The device and the process are shown in figure 1, and the implementation parameters are as follows: the reaction raw materials are vacuum wax oil, the density is 0.89, the hydrogen content is 13.2 percent (weight), the carbon residue is 4.0 percent, and the saturated hydrocarbon is 60 percent;

the preheating temperature of raw oil is 220 ℃;

the reaction device is a settler and a regenerator which are arranged in parallel, and the regenerator adopts a serial regeneration form of a quick fluidized bed of a coking tank and a dense-phase fluidized bed;

reaction conditions in the riser reaction zone: the reaction temperature TIC is controlled to 530 ℃, the average flow velocity of gas is 6.5m/s, and the reaction time is 1.7s (second); the catalyst conveying gas is steam, the quantity of the steam is 3% of the reaction raw material, and the raw material atomized steam is 7% of the raw material; the supplementary steam is 20 percent of the raw material, the catalyst entering from the lower catalyst inlet, namely the lower catalyst is a regenerated catalyst, the carbon content is 0.02 percent, and the lower catalyst temperature is 680 ℃;

reaction conditions in the fast fluidized bed reaction zone: the catalyst entering from the upper catalyst inlet, namely the upper catalyst, is a semi-regenerated catalyst, the carbon content is 0.1 percent, the temperature is 705 ℃, the reaction temperature is controlled to be 560 ℃, the average flow rate of gas is 3.5m/s, and the reaction time is 1.5 seconds; the reaction process is as follows:

atomizing the raw materials by using steam, then feeding the atomized raw materials into a riser reaction zone, and carrying out heavy oil catalytic cracking conversion under the heat provided by a lower catalyst and a catalyst environment to realize the cracking conversion of heavy oil macromolecules to intermediate molecules, so as to obtain an intermediate component raw material with a molecular weight of 100-200 as far as possible and provide an intermediate raw material for further conversion into propylene and ethylene; the gas material flow and the catalyst generated in the riser reaction zone continuously flow upwards and enter the high-temperature reaction zone; the high-temperature catalyst from the regenerator, namely the upper catalyst, enters a fast fluidized bed reaction zone, is conveyed upwards by gas from a low-temperature reaction zone and enters a high-temperature reaction zone, heat is further provided for the high-temperature reaction zone, the reaction temperature in the high-temperature reaction zone is increased, and the conversion reaction to propylene, in which the catalytic reaction of the intermediate component and the thermal reaction are combined, is realized; the reaction material flow in the high-temperature reaction zone is subjected to gas-solid separation in a settler through a gas-solid separator, and the gas with the separated catalyst flows out of the settler and enters a subsequent treatment system;

the catalyst to be regenerated separated from the settler enters a regenerator for catalyst regeneration after being stripped in a stripping section, the catalyst firstly enters an upper regeneration zone for regeneration to be a semi-regenerated catalyst, the semi-regenerated catalyst then enters a lower regeneration zone for continuous regeneration, and the catalyst is regenerated and then enters a reactor for recycling;

regeneration of the catalyst, gas-solid separation, and subsequent oil and gas treatment are common techniques, well known to the skilled artisan and not described further.

The second embodiment:

in the method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon of the embodiment, the catalytic conversion device shown in fig. 2 is adopted, a reactor R10, a regenerator G10, a settler D10 and a stripping section S10 are arranged, petroleum hydrocarbon is adopted as a raw material, and C4 is introduced into a riser reaction zone R17 to participate in catalytic reaction; the mixed C4 firstly enters a riser reaction zone R17 to react below a reaction raw material inlet R12A and then reacts with reaction raw material R12 in a riser reaction zone R17 and a fast fluidized bed reaction zone R18;

reaction make-up steam R15 is introduced into the riser reaction zone R17 and secondary reaction make-up steam R15A is introduced above the upper catalyst inlet R24A in the lower portion of the fast fluidized bed reaction zone R18; the mass ratio of steam in a riser reaction zone R17, namely a low-temperature reaction zone to reaction raw material R12 is 5-50%, and the mass ratio of steam in a fast fluidized bed reaction zone R18, namely a high-temperature reaction zone to reaction raw material R12 is 15-50%;

the regenerator G10 adopts two zones arranged in series up and down for regeneration, the lower regeneration zone G13 adopts a form of a fast fluidized bed of a coking tank, the first regeneration zone is, the upper regeneration zone G12 adopts a form of a dense-phase turbulent fluidized bed, the second regeneration zone is, namely, the regenerator G10 adopts a form of a fast fluidized bed of a coking tank and a series regeneration of a dense-phase fluidized bed, the lower part of a stripping section S10 is communicated with the lower regeneration zone G13 of the regenerator G10 through a spent riser S12 from a spent catalyst inlet G12A, spent catalyst firstly enters the lower regeneration zone G13 for regeneration and then enters the upper dense-phase fluidized bed regeneration zone G12 for regeneration;

the lower catalyst outlet G14A and the upper catalyst outlet G24A are both arranged in the upper regeneration zone G12, the upper regeneration zone G12 of the regenerator G10 is communicated with the lower catalyst inlet R14A at the lower part of the riser reaction zone R17 through the lower regeneration riser G14 from the lower catalyst outlet G14A, and the lower catalyst is provided to the riser reaction zone R17 from the upper regeneration zone G12; upper regeneration zone G12 is connected by upper catalyst outlet G24A to the lower portion of fast fluidized bed reaction zone R18 or upper catalyst inlet R24A at the outlet of riser reaction zone R17 through upper regeneration standpipe G24, and upper catalyst is supplied to fast fluidized bed reaction zone R18 from upper regeneration zone G12; the lower catalyst temperature is 660-740 ℃, and the carbon content of the catalyst is lower than 0.40 percent; the temperature of the upper catalyst is 680-730 ℃, and the carbon content of the catalyst is lower than 0.1%. The lower catalyst and the upper catalyst are both regenerated catalysts;

the other parts of the device structure are the same as the first embodiment.

The third embodiment is as follows:

the method for producing propylene and ethylene by catalytic conversion of petroleum hydrocarbon according to the present embodiment employs the catalytic conversion apparatus shown in fig. 3, which is provided with a reactor R10, a regenerator G10, a settler D10 and a stripping section S10, and uses petroleum hydrocarbon as a raw material;

the reactor R10 is set into the form of an upper and lower partitioned reactor with three catalyst circulations and two heat supplies; a return catalyst inlet R34A is provided in the lower portion of fast fluidized bed reaction zone 18, a return catalyst outlet S14A is provided in the stripping section S10, return catalyst inlet R34A is in communication with return catalyst outlet S14A through catalyst return duct S14, and a catalyst return slide valve VS14 is provided in catalyst return duct S14;

in this embodiment, in the reactor R10, the regenerated catalyst, i.e., the lower catalyst, introduced through the lower catalyst inlet R14A is the first catalyst, the regenerated catalyst, i.e., the upper catalyst, introduced through the upper catalyst inlet R24A is the second catalyst, and the spent catalyst introduced through the return catalyst inlet R34A is the third catalyst;

in the embodiment, the regenerated catalyst of the regenerator G10 enters a riser reaction zone R17 and a fast fluidized bed reaction zone R18 respectively, and the gradual temperature rise in the reaction process is realized by a graded heat supply mode; the spent catalyst part of the stripping section S10 returns to the fast fluidized bed reaction zone R18, and the catalyst inventory and the reaction weight hourly space velocity in the fast fluidized bed reaction zone R18 are controlled by the return amount of the spent catalyst; in the specific implementation process, part of spent catalyst is led from a stripping section S10 to return to a fast fluidized bed reaction zone R18, spent catalyst returns to the fast fluidized bed reaction zone R18 from a catalyst conveying pipe S14 and a return catalyst inlet R34A, the amount of the returned spent catalyst controls the catalyst inventory and the reaction weight hourly space velocity in the fast fluidized bed reaction zone R18, and the amount of the returned spent catalyst is controlled by a spent catalyst slide valve VS 14; the catalyst weight hourly space velocity in the fast fluidized bed reaction zone R18 is in the range of from 10(1/H) to 35 (1/H).

The other parts of the device structure are the same as the second embodiment.

When the method is implemented specifically, the return catalyst outlet can also be arranged above a riser reaction zone of the reactor and is communicated with the return catalyst inlet through the catalyst return conveying pipe, so that the reacted catalyst flows back in the reactor, the reacted catalyst is provided for the fast fluidized bed reaction zone, and the control of the space velocity of the catalyst in the fast fluidized bed reaction zone is realized.

The fourth embodiment:

the method for producing propylene and ethylene by catalytic conversion of petroleum hydrocarbon according to the present embodiment employs the catalytic conversion apparatus shown in fig. 4, which is provided with a reactor R10, a regenerator G10, a settler D10 and a stripping section S10, and uses petroleum hydrocarbon as a raw material;

the reactor R10 is set into the form of an upper and lower partitioned reactor with three catalyst circulations and two heat supplies; a return catalyst inlet R34A is provided in the lower portion of fast fluidized bed reaction zone R18, a return catalyst outlet S14A is provided in stripping section S10, return catalyst inlet R34A is connected to return catalyst outlet S14A by catalyst return duct S14, and a catalyst return slide valve VS14 is provided in catalyst return duct S14;

in the embodiment, the catalyst of the regenerator G10 enters a riser reaction zone R17 and a fast fluidized bed reaction zone R18 respectively, and the gradual temperature rise in the reaction process is realized by a graded heat supply mode; the spent catalyst part of the stripping section S10 returns to the fast fluidized bed reaction zone R18, and the catalyst inventory and the reaction weight hourly space velocity in the fast fluidized bed reaction zone R18 are controlled by the return amount of the spent catalyst; supplying a lower catalyst from the lower regeneration zone G13 to the riser reaction zone R17, the catalyst having a temperature of 680 ℃ to 700 ℃ and a carbon content of 0.02%; the upper regeneration zone G12 is communicated with an upper catalyst inlet R24A at the outlet of the riser reaction zone R17 through an upper regeneration standpipe G24 from an upper catalyst outlet G24A, and the upper catalyst is provided to the fast fluidized bed reaction zone R18 from an upper regeneration zone G12, the upper catalyst temperature is 740 ℃, and the carbon content is 0.15%;

the other parts of the device structure are the same as the first embodiment.

The fifth embodiment:

the method for producing propylene and ethylene by catalytic conversion of petroleum hydrocarbon according to the present embodiment employs the catalytic conversion apparatus shown in fig. 5, which is provided with a reactor R10, a regenerator G10, a settler D10 and a stripping section S10, and uses petroleum hydrocarbon as a raw material;

the reactor R10 is set into the form of an upper and lower partitioned reactor with three catalyst circulations and two heat supplies; a liquid light hydrocarbon inlet R32A is arranged at an outlet of a riser reaction zone R17, a C4 inlet R22A is arranged at the bottom of a fast fluidized bed reaction zone R18, liquid light hydrocarbon R32 enters a reactor R10 at an outlet of a riser reaction zone R17, and C4 directly enters a fast fluidized bed reaction zone R18 for reaction;

the other parts of the device structure are the same as the first embodiment.

Claims

1. A method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon is characterized in that reaction raw materials (R12) are subjected to macromolecular catalytic cracking reaction and micromolecular catalytic cracking reaction in sequence according to molecular structures; the reaction method comprises the following steps:

(1) the reaction raw material (R12) is atomized by steam and enters a riser reaction zone (R17) at the lower part of a reactor (R10) from a reaction raw material inlet (R12A), macromolecule low-temperature catalytic cracking reaction is carried out under the environment of regenerated catalyst, a lower regeneration riser (G14) conveys the regenerated catalyst from a regenerator (G10), namely the lower catalyst enters the reactor (R10) from a lower catalyst inlet (R14A) below the reaction raw material (R12), catalyst lifting gas (R11) enters the reactor (R10) from a catalyst lifting gas inlet (R11A), the catalyst is lifted to the riser reaction zone (R17), and the catalytic cracking reaction of macromolecule components in the reaction raw material (R12) is realized; the reaction temperature within the riser reaction zone (R17) is controlled by the regenerated catalyst flow from the lower regeneration standpipe (G14), the regenerated catalyst flow from the lower regeneration standpipe (G14) is controlled by the lower regeneration slide valve (VG 14);

(2) after the reaction raw material (R12) completes the macromolecule catalytic cracking reaction, the product generated in the riser reaction zone (R17) and the catalyst flow upwards to enter the fast fluidized bed reaction zone (R18), the flow velocity of gas and the catalyst is reduced in the fast fluidized bed reaction zone (R18), the density of the catalyst is increased, and the weight hourly space velocity of the catalyst is reduced; the catalyst introduced from the regenerator (G10) through the upper regeneration riser (G24) is also called as upper catalyst, enters the reactor (R10) from an upper catalyst inlet (R24A), or directly enters the fast fluidized bed reaction zone (R18), or the introduced catalyst firstly enters the reactor (R10) at the outlet of the riser reaction zone (R17) and then is conveyed to the fast fluidized bed reaction zone (R18), further provides heat for the fast fluidized bed reaction zone (R18), improves the material flow temperature and the solvent-oil ratio, and further performs catalytic cracking reaction; the reaction temperature of the fast fluidized bed reaction zone (R18) is controlled by the catalyst flow rate from the upper regeneration standpipe (G24), the catalyst flow rate from the upper regeneration standpipe (G24) is controlled by the upper catalyst slide valve (VG 24);

(3) and the reacted material flow enters a settler (D10) for gas-solid separation to obtain a reaction product (D12), and the separated catalyst enters a regenerator (G10) for regeneration after being stripped in a stripping section (S10) for recycling.

2. The process for the catalytic conversion of petroleum hydrocarbons to propylene and ethylene as claimed in claim 1, wherein the mixed C4 is introduced into the riser reaction zone (R17) below the reaction feed inlet (R12A) and then reacted with the reaction feed (R12) in the riser reaction zone (R17) and the fast fluidized bed reaction zone (R18); alternatively, C4 entered the reactor (R10) above the upper catalyst inlet (R24A) or C4 directly entered the fast fluidized bed reaction zone (R18) for reaction.

3. The process for the catalytic conversion of petroleum hydrocarbons to propylene and ethylene as claimed in claim 1, wherein a portion of spent catalyst is withdrawn from the stripping section (S10) back into the reactor (R10), or a portion of reacted catalyst is withdrawn from the reactor (R10) above the fast fluidized bed reaction zone (R18) back into the reactor (R10); spent catalyst or reacted catalyst is returned to the reactor (R10) from a catalyst return duct (S14) and a return catalyst inlet (R34A), the return catalyst inlet (R34A) being provided at the outlet of the riser reaction zone (R17) or at the bottom of the fast fluidized bed reaction zone (R18); the return amount of spent catalyst or reacted catalyst is controlled by the catalyst inventory and the weight hourly space velocity of the reaction catalyst in the fast fluidized bed reaction zone (R18), and the return amount of spent catalyst or reacted catalyst is controlled by the catalyst return slide valve (VS 14).

4. The process of claim 1, wherein more than 90% by weight of the liquid light hydrocarbon (R32) having a boiling point or end point of less than 360 ℃ enters the reactor (R10) at the outlet of the riser reaction zone (R17) or directly enters the fast fluidized bed reaction zone (R18).

5. The process for the catalytic conversion of petroleum hydrocarbons to propylene and ethylene as claimed in claim 1, wherein the regenerator (G10) has two upper and lower regeneration zones, lower regeneration zone (G13) and upper regeneration zone (G12) disposed below the dilute phase zone (G15), the lower regeneration zone (G13) is the first regeneration zone, the upper regeneration zone (G12) is the second regeneration zone, the spent catalyst from the stripping section (S10) enters the lower regeneration zone (G13), and the regenerated catalyst, lower catalyst and upper catalyst, are supplied from the upper regeneration zone (G12) to the reactor (R10);

or, an upper regeneration zone and a lower regeneration zone, namely a lower regeneration zone (G13) and an upper regeneration zone (G12), are arranged below a regenerator dilute phase zone (G15) of the regenerator (G10), the upper regeneration zone (G12) is a first regeneration zone, the lower regeneration zone (G13) is a second regeneration zone, the spent catalyst from the stripping section (S10) enters the upper regeneration zone (G12), the lower catalyst provided to a riser reaction zone (R17) through the lower regeneration standpipe (G14) is regenerated catalyst, and the upper catalyst provided to a reactor (R10) through the upper regeneration standpipe (G24) is semi-regenerated catalyst; the carbon content and temperature of the catalyst in the two regeneration zones are adjusted by adjusting the amount of the catalyst in the lower regeneration zone (G13) and the distribution of the regeneration oxygen amount in the upper regeneration zone (G12).

6. The method for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon according to claim 1, wherein the reaction temperature of the riser reaction zone (R17) is 515-620 ℃, and the reaction time is 0.5-1.5 s; the reaction temperature of the rapid fluidized bed reaction zone (R18) is 530-720 ℃, the reaction time is 0.5-4.0 s, and the absolute pressure of the reaction pressure is 0.20-0.26 MPa.

7. The process for the catalytic conversion of petroleum hydrocarbon to propylene and ethylene as claimed in claim 1, wherein the riser reaction zone (R17) is in the form of gas-solid pneumatic conveying fluidization with a gas average flow velocity of 5.0-20 m/s; the diameter of the fast fluidized bed reaction zone (R18) is larger than that of the riser reaction zone (R17), the fast gas-solid fluidized bed condition is adopted, and the average gas flow speed is 1.8-5.0 m/s.

8. A device for preparing propylene and ethylene by catalytic conversion of petroleum hydrocarbon is characterized in that a reactor (R10), a regenerator (G10), a settler (D10) and a stripping section (S10) are arranged, a lower regeneration riser (G14) and a lower regeneration slide valve (VG14), an upper regeneration riser (G24) and an upper catalyst slide valve (VG24), a spent riser (S12) and a spent catalyst slide valve (VS12) are arranged; the regenerator (G10) and the settler (D10) are arranged in parallel, and are characterized in that:

the reactor (R10) is divided into two sections or two sections which are connected in series up and down, and comprises a riser reaction zone (R17) at the lower part and a fast fluidized bed reaction zone (R18) at the upper part, wherein the riser reaction zone (R17) is in a gas-solid pneumatic conveying fluidization form with high gas flow velocity, the fast fluidized bed reaction zone (R18) is in a fast fluidized bed form with reduced gas flow velocity, and the diameter of the fast fluidized bed reaction zone (R18) is larger than that of the riser reaction zone (R17); a reaction feed inlet (R12A) is provided in the lower portion of the riser reaction zone (R17);

a lower catalyst inlet (R14A) at the lower part of the riser reaction zone (R17) is arranged below the reaction raw material inlet (R12A), and the lower catalyst inlet (R14A) is communicated with a lower catalyst outlet (G14A) of the regenerator (G10) through a lower regeneration vertical pipe (G14); an upper catalyst inlet (R24A) is provided at the bottom of the fast fluidized bed reaction zone (R18) or at the outlet of the riser reaction zone (R17), said upper catalyst inlet (R24A) being in communication with the upper catalyst outlet (G24A) of said regenerator (G10) via an upper regeneration standpipe (G24); a lower regeneration slide valve (VG14) is arranged on the lower regeneration vertical pipe (G14), and an upper catalyst slide valve (VG24) is arranged on the upper regeneration vertical pipe (G24);

the stripping section (S10) is communicated with the regenerator (G10) through a spent catalyst outlet (S12A), a spent riser (S12) and a spent agent inlet (G12A), and a spent catalyst slide valve (VS12) is arranged on the spent riser (S12).

9. The apparatus for the catalytic conversion of petroleum hydrocarbons to propylene and ethylene as claimed in claim 8, wherein a return catalyst inlet (R34A) is provided at the lower portion of said fast fluidized bed reaction zone (R18) or at the outlet of said riser reaction zone (R17), a return catalyst outlet (S14A) is provided above said stripping section (S10) or fast fluidized bed reaction zone (R18), and said return catalyst inlet (R34A) is in communication with said return catalyst outlet (S14A) through a catalyst return duct (S14); a catalyst return slide valve (VS14) is provided in the catalyst return delivery pipe (S14).

10. The apparatus for the catalytic conversion of petroleum hydrocarbons to propylene and ethylene as claimed in claim 8, wherein the regenerator (G10) has two upper and lower regeneration zones, a lower regeneration zone (G13) and an upper regeneration zone (G12), below the dilute phase zone (G15) of the regenerator;

the lower catalyst outlet (G14A) and the upper catalyst outlet (G24A) are both arranged in the upper regeneration zone (G12), and the spent agent inlet (G12A) is arranged in the lower regeneration zone (G13);

alternatively, the lower catalyst outlet (G14A) is arranged in the lower regeneration zone (G13), the upper catalyst outlet (G24A) is arranged in the upper regeneration zone (G12), and the spent agent inlet (G12A) is arranged in the upper regeneration zone (G12).