CN111689829B - Method and device for preparing ethylene by catalytic conversion of petroleum hydrocarbon - Google Patents

Abstract

The invention relates to a method for preparing ethylene by catalytic conversion of petroleum hydrocarbon, belonging to the technical field of catalytic conversion of petroleum hydrocarbon. The method is provided with a reactor (R10) and a second reactor (R20), wherein the second reactor (R20) is provided with an upper reaction zone and a lower reaction zone, namely a lower reaction zone (R27) and an upper reaction zone (R28), heavy petroleum hydrocarbon R12 is subjected to independent catalytic conversion in the reactor (R10), light hydrocarbon (R22) sequentially reacts in the lower reaction zone (R27) with low temperature and the upper reaction zone (R28) with high temperature, a catalyst of a regenerator (G10) respectively enters the lower reaction zone (R27) and the upper reaction zone (R28), and gradual temperature rise in the reaction process is realized in a graded heat supply mode. The invention also provides a device for realizing the method.

Description

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

Background

The low-carbon olefin represented by ethylene and propylene is the most basic raw material in chemical industry, and the existing catalytic conversion technology is used for producing gasoline and diesel oil and simultaneously producing the low-carbon olefin as a byproduct, so that the requirement of the current market on organic chemical raw materials can not be met. Natural gas or light petroleum fractions are mostly used as raw materials at home and abroad, and low-carbon olefin is produced by adopting a steam cracking process in an ethylene combined device. Although the steam cracking technology is developed for decades and the technology is continuously improved, the steam cracking technology still has the advantages of high energy consumption, high production cost and CO ₂ The discharge amount is large, the product structure is not easy to adjust, and other technical limitations, and the traditional technology for producing ethylene and propylene by steam cracking is facing a severe test. The catalytic conversion method is used for preparing ethylene, and meanwhile, the by-products of chemical raw materials such as low-carbon olefins such as propylene, butylene and the like are new directions for solving the problems of resource shortage and low-cost production of chemical products, and become important research subjects and hot problems at present.

In the aspect of preparing ethylene by catalytic conversion and by-producing low-carbon olefins such as propylene, butylene and the like, the following ideas are mainly provided:

1. the reaction raw material is divided into different fractions by a distillation tower, and the different fractions are respectively subjected to catalytic reaction in different reactors. For example, CN109575982a provides a method for preparing low carbon olefins and aromatic hydrocarbons by catalytic cracking of crude oil, the crude oil is desalted and dehydrated, then heated in a heating furnace, and then enters a distillation tower to separate the crude oil into light and heavy components, and the cutting point is between 150 ℃ and 300 ℃; the light components coming out of the top of the tower and the heavy components coming out of the bottom of the tower contact and react with the high-temperature catalyst in the atmosphere of water vapor in the two reactors.

2. The materials in the reactor are fed and reacted layer by layer. For example, CN1898362 provides a method for producing light olefins and aromatics, in which a raw material is contacted with a catalytic cracking catalyst, the reaction is divided into at least two layers of feeding materials according to the properties of the raw material, and different liquid reaction products from a fractionating tower except for a target product are returned to a reactor from different positions for conversion again. CN1215041A provides a method for preparing ethylene, propylene, aromatic hydrocarbon and the like by directly converting various feed hydrocarbons into olefins, and a reactor is provided with a plurality of groups of feed inlets, so that hydrocarbons with different properties enter a device from different feed inlets, and are subjected to cracking reaction under the same process conditions of all parts. CN104560154A provides a hydrocarbon catalytic conversion method for producing light olefins and light aromatics in high yield, which comprises the following steps: contacting a heavy hydrocarbon raw material with a cracking catalyst in a first reactor to perform catalytic cracking reaction, and then separating to obtain a first carbon deposition catalyst and a first reaction product; injecting light hydrocarbon raw materials from the upstream of the second reactor, and injecting medium hydrocarbon raw materials from the middle part of the second reactor to perform catalytic cracking reaction; and introducing the reaction mixture generated in the second reactor into a third reactor to continue reacting, and then separating to obtain a second carbon deposition catalyst and a second reaction product. Wherein the cracking catalyst is a cracking catalyst containing modified beta zeolite, and the modified beta zeolite is beta zeolite modified by Lin and transition metal M.

3. Outside the raw oil riser, additionally establishing a reactor to convert different fractions by catalysis again, namely adopting a multi-reactor form, carrying out conventional raw oil reaction in the first reactor, and feeding one or more fractions such as crude gasoline into the additionally established reactor for further conversion to obtain a target product after fractionation; for example, CN1388216 discloses a catalytic conversion method for preparing propylene, butylene and gasoline with low olefin content, which comprises the following steps: (1) Injecting preheated hydrocarbon oil (still liquid) into a riser, contacting and reacting with a catalyst containing pentasil zeolite and Y-type zeolite, and introducing an oil agent mixture into a fluidized bed through the riser; (2) Injecting gasoline into the fluidized bed, and contacting and reacting with the catalyst from the riser; (3) Separating the oil mixture, stripping the reacted catalyst, regenerating in a regenerator, and returning the regenerated catalyst to the riser for reuse. The method can not only increase the yield of low-carbon olefin, but also produce high-quality gasoline with low olefin content. CN1258580C discloses a method and a system for upgrading gasoline by deeply reducing olefin and increasing octane number by catalytic conversion, which is to add a catalytic upgrading reactor in a reaction-regeneration system of a heavy oil catalytic conversion device to carry out catalytic upgrading reaction on gasoline fraction by catalytic conversion. The upgraded catalytically converted gasoline fraction may be a naphtha whole fraction, a naphtha light fraction or a naphtha heavy fraction obtained by establishing a secondary condensation system at the top of the fractionator.

4. Light raw material is used for producing low-carbon olefin. CN104557378A discloses a method for producing propylene by naphtha catalytic cracking. The method comprises the following steps: (1) Under the pretreatment condition, contacting naphtha with a pretreatment agent to obtain treated oil with reduced alkaline nitrogen content; (2) And (2) under the condition of naphtha catalytic cracking reaction, contacting the treated oil and water obtained in the step (1) with a catalyst to obtain a catalytic cracking product.

5. In order to increase the yield of the light olefins, a 'cocatalyst' suitable for cracking the small-molecular hydrocarbons can be added, and the propylene can be increased by 1-1.5% by adding 5-8% of the heavy oil reaction catalyst.

The above technologies for reducing olefins by Fluidized Catalytic Conversion (FCC) and increasing the production of chemical feedstocks have some common drawbacks as follows:

1. different raw materials require different catalysts, heavy oil cracking requires high macromolecule cracking capability of the catalyst, and generally requires a larger aperture; the cracking of C4 and C5 requires a catalyst with low carbon olefin selectivity, and generally requires a smaller pore diameter; the prior art processes described above all use the same catalyst, i.e., only one catalyst. Although 5-8% of auxiliary agent can be added into the regenerator to further convert the small molecules in order to increase the yield of the low-carbon olefins, when the auxiliary agent is added into the FCC catalyst, the catalyst cracking activity is inevitably reduced due to the dilution effect on the catalyst. The heavy oil cracking conversion rate is reduced by 1 percentage point per 5% of the addition of the promoter, which is an important factor that seriously affects the economy of the FCC technology, and the improvement of the objective product is limited due to the low concentration of the promoter after mixing with the heavy oil cracking catalyst.

2. Because the second reaction system needs more reaction heat and generally has less coke formation, the heat generated by the regeneration of the coke formation can not provide the heat required by the reaction, and if the independent second reaction system is established by utilizing the prior art, the heat balance problem is restricted.

3. In all the recycling methods, the fraction is separated by a fractionating tower, cooled into liquid by heat exchange and then returned to the reactor, different fractions are firstly cooled into liquid by the heat exchange of the fractionating tower, and the liquid is returned to the original reactor or is further converted by another reactor directly after separation or after proper re-preheating (still liquid). Through the processes of cooling and heating, the investment of equipment and energy consumption is increased, and the economical efficiency of the process technology is greatly reduced.

4. The preparation of ethylene from petroleum hydrocarbon requires higher reaction temperature, generally higher than 650 ℃; the reaction process of catalytically preparing olefin from catalytically cracked material oil, especially heavy material oil, is a process of gradually cracking and gradually reducing molecular weight; small molecules are difficult to activate, the higher the required reaction temperature is, the higher the temperature is, the thermal cracking reaction is naturally carried out, and the selectivity of target products is influenced; how to allocate the reaction temperature and the molecular characteristics of petroleum hydrocarbon well, balance the catalytic cracking reaction and the thermal cracking reaction well, and have important significance for realizing the limit control of the reaction; the expected reaction process is that the specific gravity of catalytic reaction is increased as much as possible in the macromolecular cracking stage of heavy oil and the like, thermal cracking is limited, the temperature is gradually increased in the lower molecular cracking stage, and the thermal cracking reaction proportion is increased; however, in the prior art, heat is provided in the inlet area of the reactor in the reaction process, the reaction is a gradual cooling process, particularly for the reaction for preparing ethylene, the reaction temperature is higher in the initial stage, namely the heavy oil cracking stage at the lower part of the reactor, and heavy components are directly subjected to thermal cracking reaction, so that the effect of catalytic cracking reaction is reduced.

Disclosure of Invention

The invention aims to provide a method for preparing ethylene by catalytic conversion of petroleum hydrocarbon, which can realize high-yield preparation of various low-carbon olefin products such as ethylene, propylene and the like, has low equipment investment and low energy consumption, and can be used for simultaneously treating heavy petroleum hydrocarbon and light hydrocarbon raw materials to produce ethylene products. The invention also provides a device for preparing ethylene by catalytic conversion of petroleum hydrocarbon.

The invention adopts the following technical scheme:

a method for preparing ethylene by catalytic conversion of petroleum hydrocarbon is characterized in that heavy petroleum hydrocarbon and light hydrocarbon are subjected to catalytic conversion in a reactor and a second reactor respectively, the second reactor is provided with an upper reaction zone and a lower reaction zone, namely a lower reaction zone with a lower temperature and an upper reaction zone with a raised temperature, the light hydrocarbon sequentially enters the lower reaction zone with a lower temperature and the upper reaction zone with a higher temperature to realize low-temperature catalytic cracking reaction and high-temperature ethylene preparation cracking reaction, catalysts of a regenerator respectively enter the lower reaction zone and the upper reaction zone, and the gradual temperature rise in the reaction process is realized by a graded heat supply mode; the reaction process comprises the following steps:

(1) The heavy petroleum hydrocarbon enters a reactor and is subjected to catalytic cracking reaction in the catalyst environment from a regenerator, the reaction temperature at the outlet of the reactor is 490-700 ℃, the reaction time is 0.5-5.0 s, and the absolute pressure of the reaction pressure is 0.23-0.40 Mpa;

(2) Light hydrocarbon enters a second reactor for catalytic conversion;

the light hydrocarbon enters a lower reaction zone at the lower part of the second reactor, and is subjected to catalytic cracking reaction in the environment of a lower regenerant introduced from a regenerator through a lower regeneration vertical pipe; the reaction temperature of the lower reaction zone is 530-620 ℃, and the reaction time is 0.5-3.0 s;

after the low-temperature catalytic cracking reaction of the light hydrocarbon is completed, the product and the catalyst generated in the lower reaction zone flow upwards and enter the upper reaction zone, the upper regenerant introduced from the regenerator through the upper regeneration vertical pipe enters the upper reaction zone, heat is provided to the upper reaction zone, the temperature and the catalyst-to-oil ratio are improved, and the catalytic cracking and thermal cracking combined reaction is continuously carried out; the reaction temperature of the upper reaction zone is 550-750 ℃, the reaction time is 0.2-3.0 s, and the absolute pressure of the reaction pressure is 0.20-0.40 MPa;

(3) And the material flow reacted by the second reactor and the material flow reacted by the reactor enter a settler together 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 above method for producing ethylene by catalytic conversion of petroleum hydrocarbon, the heavy petroleum hydrocarbon is one or a mixture of vacuum wax oil, (atmospheric) residual oil, coker wax oil, deasphalted oil, hydrogenated wax oil (hydrotreated wax oil), hydrogenated residual oil (hydrotreated residual oil), and crude oil, and the boiling point is higher than 320 ℃. The light hydrocarbon is petroleum hydrocarbon with the boiling point lower than 360 ℃. Preferably, the light hydrocarbon is one or a mixture of naphtha, C4, C5, hydrocatalytic (cracked) diesel components.

The method for preparing ethylene by catalytic conversion of petroleum hydrocarbon further comprises the step of supplementing heavy oil or recycling refined oil at any 1-3 positions of the downstream of the upper reaction zone, the downstream of the stripping section and the downstream of the reactor of the second reactor, and is used for increasing coke formation heat supplement and oil gas temperature reduction.

In the method for preparing ethylene by catalytic conversion of petroleum hydrocarbon, an upper regeneration zone and a lower regeneration zone, namely a lower regeneration zone and an upper regeneration zone, are further arranged below a dilute phase zone of a regenerator of the regenerator, and a regenerant is provided for the reactor and the second reactor through the upper regeneration zone.

The invention also provides a device for preparing ethylene by catalytic conversion of petroleum hydrocarbon, which is provided with a reactor, a second reactor, a regenerator, a settler and a stripping section, wherein the regenerator and the settler are arranged in parallel,

the second reactor and the reactor share a settler, a stripping section and a regenerator; a heavy petroleum hydrocarbon inlet is arranged at the lower part of the reactor; the lower part of the reactor is provided with a regenerant inlet which is communicated with a regenerant outlet of the regenerator through a regeneration vertical pipe, the second reactor is arranged into an upper-lower partitioned reactor form with upper and lower catalyst circulation and twice heat supply, and comprises a lower reaction zone at the lower part and an upper reaction zone at the upper part, the lower reaction zone is used for low-temperature catalytic cracking reaction at lower temperature, and the upper reaction zone is used for high-temperature ethylene preparation cracking reaction; a light hydrocarbon inlet is arranged at the lower part of the lower reaction zone; and a lower regenerant inlet at the lower part of the lower reaction zone is communicated with a lower regenerant outlet of the regenerator through a lower regeneration vertical pipe, and an upper regenerant inlet at the lower part of the upper reaction zone is communicated with an upper regenerant outlet of the regenerator through an upper regeneration vertical pipe.

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 the regenerator, and a regenerant outlet, a lower regenerant outlet and an upper regenerant outlet are arranged in the upper regeneration zone.

Effects of the invention

The invention provides a method for preparing ethylene by gradual temperature rise and two-stage temperature gradient conversion based on a catalytic cracking mechanism. By controlling the ratio of the catalyst to the oil and the temperature in the reaction process, particularly along with the reaction, the ratio of the catalyst to the oil and the temperature are gradually increased, 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 the cracking process of the heavy petroleum hydrocarbon; the common conversion effect of heavy components and light hydrocarbon raw materials with different properties is locally and well optimized, and the excessive cracking of small molecular light hydrocarbon is avoided, so that the cracking conditions of the heavy components and the light hydrocarbon are ensured; 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;

the numbering in the figures illustrates:

an R10 reactor; r11 catalyst pre-lift gas; an R11A catalyst pre-lift gas inlet, R12 heavy petroleum hydrocarbon; an R12A reaction raw material inlet, R13 raw material atomized steam, an R14 regeneration slide valve, an R14A regenerant inlet, an R20 second reactor or a light hydrocarbon reactor, and an R20A second catalyst lift gas; the reaction zone under R21 is supplemented with steam and R22 light hydrocarbon; steam is supplemented to the reaction zone on R23, a regeneration slide valve is arranged on R24, and a regenerant inlet is arranged on R24A; r27 lower reaction zone, R28 upper reaction zone, R29 second reactor make-up recycle oil, R34 lower regeneration slide valve, R34A lower regenerant inlet;

s10, a stripping section, S11, a stripping component; s12, a spent catalyst slide valve, an S12A spent vertical pipe or a spent catalyst conveying pipe and S13 steam stripping;

d10, D11, a settling cyclone separator; d12 reaction product, and a D12A reaction settler product outlet;

the device comprises a G10 regenerator, G11 catalyst regeneration gas, a G11A regeneration gas inlet, a G12 upper regeneration zone, a G12A spent agent inlet, G13 fuel oil, a G14 regeneration vertical pipe or a regeneration agent conveying pipe, a G14A regeneration agent outlet, a G15 regenerator dilute phase zone, a G16 regeneration cyclone separator, G17 burnt flue gas, a G17A flue gas outlet, G18 second regeneration gas and a G19 lower regeneration zone; g24, a regeneration vertical pipe or a regeneration agent conveying pipe is arranged, and G24A is provided with a regeneration agent outlet; g34 lower regeneration vertical pipe, G34A lower regenerant outlet;

a0, heating the furnace by using a furnace,

TIC temperature display control; controlling the outlet temperature of the lower reaction zone of TIC-1, controlling the outlet temperature of the TIC-2 reactor, and controlling the outlet temperature of the upper reaction zone of TIC-3.

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:

the method for producing ethylene by catalytic conversion of petroleum hydrocarbon according to the present embodiment employs the catalytic converter shown in FIG. 1, which comprises a reactor R10, a second reactor R20, a regenerator G10, a settler D10 and a stripping section S10,

the heavy petroleum hydrocarbon and the light hydrocarbon are used as raw materials, and in the specific implementation, the heavy petroleum hydrocarbon can be one or a mixture of vacuum wax oil, residual oil, coking wax oil, deasphalted oil, wax oil after hydrotreating, residual oil after hydrotreating and crude oil, and the boiling point is higher than 320 ℃; the light hydrocarbon R22 is petroleum hydrocarbon with the boiling point lower than 360 ℃, preferably one or a mixture of naphtha, C4, C5 and hydrocatalytically cracked diesel components;

the regenerator G10 and the settler D10 are arranged in parallel, the outlet of the reactor R10 is communicated with a settling cyclone separator 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 second reactor R20 shares a settler D10, a stripping section 10 and a regenerator G10 with the reactor R10; a heavy petroleum hydrocarbon inlet R12A is arranged at the lower part of the reactor R10 to introduce the heavy petroleum hydrocarbon R12 and the raw material atomization steam R13, and a catalyst pre-lifting gas inlet R11A is arranged at the bottom of the reactor R10 to introduce the catalyst pre-lifting gas R11; a reaction settler product outlet D12A is arranged at the top of the settler D10 to lead out a reaction product D12; a regenerant inlet R14A at the lower part of the reactor R10 is communicated with a regenerant outlet G14A of the regenerator G10 through a regeneration vertical pipe G14;

the second reactor 20 is set into a form of an upper and lower partitioned reactor with upper and lower catalyst circulation and twice heat supply, and comprises a lower reaction zone R27 at the lower part and an upper reaction zone R28 at the upper part, wherein the lower reaction zone R27 is used for low-temperature catalytic cracking reaction, and the upper reaction zone R28 is used for high-temperature ethylene preparation cracking reaction; a light hydrocarbon inlet is arranged at the lower part of the lower reaction zone R27 to introduce a light hydrocarbon R22, and a second catalyst lifting gas R20A is introduced at the lower part of the second reactor R20; a lower regenerant inlet R34A at the lower portion of the lower reaction zone R27 is in communication with a lower regenerant outlet G34A of the regenerator G10 through a lower regeneration standpipe G34, and an upper regenerant inlet R24A at the lower portion of the upper reaction zone R28 is in communication with an upper regenerant outlet G24A of the regenerator G10 through an upper regeneration standpipe G24;

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 G19 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 G19 adopts a coking tank fast fluidized bed form, the upper regeneration zone G12 adopts a dense-phase fluidized bed form, namely the regenerator G10 adopts a coking tank fast fluidized bed and dense-phase fluidized bed series regeneration form, and a regenerant outlet G14A, a lower regenerant outlet G14A and an upper regenerant outlet G24A are arranged in the upper regeneration zone G12, so that a regenerant is provided for the reactor R10 and the second reactor R20 through the upper regeneration zone G12; the lower part of the stripping section S10 is communicated with a lower regeneration zone G19 of the regenerator G10 through a spent riser S12A from a spent agent inlet G12A, and a spent catalyst slide valve S12 is arranged on the spent riser S12A;

in specific implementation, an upper regeneration zone G12 of the regenerator G10 is communicated with a regenerant inlet R14A at the lower part of the reactor R10 through a regenerant outlet G14A through a regeneration vertical pipe G14, and the regeneration vertical pipe G14 is provided with a regeneration slide valve R14;

the upper regeneration zone G12 is communicated with an upper regenerant inlet R24A at the lower part of the upper reaction zone R28 through an upper regenerant outlet G24A by an upper regeneration vertical pipe G24, and an upper regeneration slide valve R24 is arranged on the upper regeneration vertical pipe G24; the upper regeneration zone G12 is communicated with a lower regeneration agent inlet R34A at the lower part of the lower reaction zone R27 through a lower regeneration standpipe G34 by a lower regeneration agent outlet G34A, and a lower regeneration slide valve R34 is arranged on the lower regeneration standpipe G34;

a regeneration cyclone separator G16 is arranged in a regenerator dilute phase zone G15 of the regenerator G10, flue gas G17 generated 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; a second regeneration gas G18 is introduced into the regenerator G10 from the lower portion of the upper regeneration zone G12;

introducing lower reaction zone make-up steam R21 above a lower regenerant inlet R34A in the lower portion of the lower reaction zone R27 and upper reaction zone make-up steam R23 above an upper regenerant inlet R24A in the lower portion of the upper reaction zone R28; introducing a second reactor supplemented recycle oil R29 at the downstream of the upper reaction zone R28, and during specific implementation, introducing steam stripping supplemented recycle oil at a steam stripping section S10, or introducing reaction supplemented recycle oil at the downstream of the reactor R10 to realize coke formation heat supplementation and oil gas cooling; introducing fuel oil G13 into the lower part of the upper regeneration zone G12;

setting a heating furnace A0, preheating a light hydrocarbon R22 in the heating furnace A0, then entering a second reactor R20, reacting in the second reactor R20 to form a material flow, and entering a settler D10 together with the material flow formed by the reaction of the reactor R10 to separate a catalyst, thus obtaining a reaction product D12;

heavy petroleum hydrocarbon R12 is preheated in the heating furnace A0 and then enters the reactor R10 to participate in catalytic conversion.

In the invention, heavy petroleum hydrocarbon R12 and light hydrocarbon R22 are respectively subjected to catalytic conversion in a reactor R10 and a second reactor R20, the second reactor R20 is arranged into an upper reaction zone and a lower reaction zone, namely a lower reaction zone R27 and an upper reaction zone R28, the light hydrocarbon R22 sequentially enters the lower reaction zone R27 with low temperature and the upper reaction zone R28 with high temperature to realize low-temperature catalytic cracking reaction and high-temperature ethylene cracking reaction, the catalyst of a regenerator G10 respectively enters the lower reaction zone R27 and the upper reaction zone R28, 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) Heavy petroleum hydrocarbon R12 is preheated in a heating furnace A0, atomized by raw material atomizing steam R13 and enters a reactor R10, a catalyst from an upper regeneration area G12 of the regenerator G10 from a regeneration vertical pipe G14 enters the reactor R10 from a regenerant inlet R14A, and is conveyed upwards to contact with the raw material under the action of catalyst pre-lifting gas R11, the heavy petroleum hydrocarbon R12 is subjected to catalytic conversion in a catalyst environment, the reaction temperature at the outlet of the reactor R10 is 490-700 ℃, the reaction time is 0.5-5.0 s, and the absolute pressure of the reaction pressure is 0.23-0.40 MPa; the actual reaction temperature is controlled by the amount of catalyst entering reactor R10;

(2) Light hydrocarbon R22 enters a second reactor R20 for catalytic conversion;

after being preheated in the heating furnace A0, the light hydrocarbon R22 firstly enters a lower reaction zone R27 at the lower part of a second reactor R20, a lower regenerant from an upper regeneration zone G12 from a lower regeneration vertical pipe G34 enters the second reactor R20 from a lower regenerant inlet R34A, is conveyed upwards under the action of a second catalyst lifting gas R20A to be contacted with the light hydrocarbon R22, and carries out catalytic cracking reaction under the environment of the lower regenerant introduced from a regenerator G10 through the lower regeneration vertical pipe G34; the light hydrocarbon R22 is subjected to low-temperature catalytic cracking in the lower regenerant environment, the reaction temperature of the lower reaction zone R27 is 530-620 ℃, and the reaction time is 0.5-5.0 s; the actual reaction temperature is controlled by the amount of catalyst entering the lower reaction zone R27;

after the light hydrocarbon R22 finishes the low-temperature catalytic cracking reaction, the product and the catalyst generated in the lower reaction zone R27 flow upwards to enter the upper reaction zone R28, the upper regenerant from the upper regeneration zone G12 from the upper regeneration riser G24 enters the upper reaction zone R28 from the upper regenerant inlet R24A, heat is provided for the upper reaction zone R28, the temperature and the agent-oil ratio are improved, and the catalytic cracking and thermal cracking combined reaction is continuously carried out; the reaction temperature of the upper reaction zone R28 is 550-750 ℃, the reaction time is 0.1-5.0 s, and the absolute pressure of the reaction pressure is 0.20-0.40 MPa; the actual reaction temperature is controlled by the amount of catalyst entering the upper reaction zone R28; a second reactor additionally recycled oil R29 introduced at the upstream of the upper reaction zone R28 realizes coke formation heat supplement and oil gas cooling;

(3) And the material flow reacted by the second reactor R20 and the material flow reacted by the reactor R10 enter a precipitator D10 together for gas-solid separation to obtain a reaction product D12, and the separated catalyst is subjected to steam stripping in a steam stripping section S10 and then enters a regenerator G10 for regeneration and recycling.

In specific implementation, after the reaction product D12 leaves the catalytic conversion device shown in FIG. 1, quenching and cooling are firstly carried out, the continuous reaction is stopped, the subsequent treatment and the coking of a conveying pipeline are avoided, and then the product fractionation is carried out; the product gas can be quenched by directly generating steam, or quenched by directly mixing other heat exchange and low-temperature media; quenching and fractionation, 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 heavy petroleum hydrocarbon is 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 light hydrocarbon is naphtha;

preheating the heavy raw oil at 220 ℃; the light hydrocarbon preheating temperature is 550 ℃;

the reaction device is a settler and a regenerator which are arranged in parallel, the regenerator adopts a serial regeneration form of a fast fluidized bed and a dense-phase fluidized bed of a coke burning tank, and the reactor R10 and the second reactor are riser reactors;

reactor R10 reaction conditions: the reaction temperature TIC-2 was 630 ℃ and the reaction time was 1.2s (sec); the temperature of the regenerant entering from the regenerant inlet of the reactor is 720 ℃;

r20 reaction zone R27 reaction conditions: the reaction temperature TIC-1 is controlled to 530 ℃, and the reaction time is 1.1s (second); the catalyst conveying gas is steam, the quantity of the steam is 6% of the light hydrocarbon raw material, and the atomized steam is 10% of the raw material; the temperature of the lower regenerant is 720 ℃;

reaction conditions in the upper reaction zone: the temperature of the upper regenerant is 725 ℃, the reaction temperature TIC-3 is controlled to be 665 ℃, the reaction time is 0.6 second, the proportion of steam is 30 percent, and the supplementary steam is 14 percent of the raw material;

the reaction process is as follows:

the preheated heavy raw oil enters a reactor after being atomized by steam, and heavy oil catalytic cracking conversion is carried out under the heat provided by a regenerant and a catalyst environment;

the preheated light hydrocarbon enters a lower reaction zone of a second reactor, and low-temperature catalytic cracking conversion of the light hydrocarbon is carried out under the heat provided by a lower regenerant and a catalyst environment to obtain an intermediate component raw material with the molecular weight of 100-200, and the intermediate raw material is provided for further conversion into propylene and ethylene; the gas stream and catalyst produced in the lower reaction zone continue to flow upwardly into the upper reaction zone; the high-temperature catalyst from the regenerator, namely the upper catalyst, enters the upper reaction zone, is conveyed upwards by the gas from the lower reaction zone to enter the high-temperature upper reaction zone, further provides heat for the upper reaction zone, improves the reaction temperature in the upper reaction zone, and realizes the conversion reaction to ethylene by combining the catalytic reaction and the thermal reaction of the intermediate component;

the material flow reacted by the second reactor and the material flow reacted by the reactor are subjected to gas-solid separation in a settler through a gas-solid separator, and the gas with the catalyst separated out 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, enters a lower regeneration zone firstly, and then is conveyed to an upper regeneration zone by coke-burning gas, and the catalyst enters a reactor after being regenerated 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.

Table 1 shows the product distribution of example 1.

Table 1 example 1 product distribution

Components	Unit% (weight)
		Dry gas	33.56
Wherein:
		H	0.14
methane	12.27
		Ethane (III)	4.58
Ethylene	15.45
		Liquefied gas	32
Wherein:
		propane	2.15
Propylene (PA)	18.96
		Butane	1.42
Butene (butylene)	8.71
		Gasoline (gasoline)	13.89
Diesel oil	9.33

Claims (7)

1. A method for preparing ethylene by catalytic conversion of petroleum hydrocarbon is characterized in that heavy petroleum hydrocarbon (R12) and light hydrocarbon (R22) are subjected to catalytic conversion in a reactor (R10) and a second reactor (R20) respectively, the second reactor (R20) is provided with an upper reaction zone and a lower reaction zone, namely a lower reaction zone (R27) and an upper reaction zone (R28), the light hydrocarbon (R22) sequentially enters the lower reaction zone (R27) with low temperature and the upper reaction zone (R28) with high temperature to realize low-temperature catalytic cracking reaction and high-temperature ethylene preparation cracking reaction, a catalyst of a regenerator (G10) respectively enters the lower reaction zone (R27) and the upper reaction zone (R28), and gradual temperature rise in the reaction process is realized by a graded heat supply mode; the reaction process comprises the following steps:

(1) Heavy petroleum hydrocarbon (R12) enters a reactor (R10) and is subjected to catalytic cracking reaction under the environment of a catalyst from a regenerator (G10), the reaction temperature of the reactor outlet of the reactor (R10) is 490-700 ℃, the reaction time is 0.5-5.0 s, and the absolute pressure of the reaction pressure is 0.23-0.40 Mpa;

(2) Light hydrocarbon (R22) enters a second reactor (R20) for catalytic conversion;

the light hydrocarbon (R22) firstly enters a lower reaction zone (R27) at the lower part of the second reactor (R20) and carries out catalytic cracking reaction under the environment of a lower regenerant introduced from a regenerator (G10) through a lower regeneration vertical pipe (G34); the reaction temperature of the lower reaction zone (R27) is 530-620 ℃, and the reaction time is 0.5-3.0 s;

after the low-temperature catalytic cracking reaction of the light hydrocarbon (R22) is finished, products and a catalyst generated in the lower reaction zone (R27) flow upwards to enter the upper reaction zone (R28), an upper regenerant introduced from the regenerator (G10) through the upper regeneration vertical pipe (G24) enters the upper reaction zone (R28), heat is provided for the upper reaction zone (R28), the temperature and the catalyst-to-oil ratio are improved, and the combined reaction of catalytic cracking and thermal cracking is continuously carried out; the reaction temperature of the upper reaction zone (R28) is 550-750 ℃, the reaction time is 0.2-3.0 s, and the absolute pressure of the reaction pressure is 0.20-0.40 MPa;

(3) The material flow reacted by the second reactor (R20) and the material flow reacted by the reactor (R10) enter a settler (D10) together 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 ethylene according to claim 1, wherein the heavy petroleum hydrocarbons (R12) are one or a mixture of vacuum wax, residual oil, coker wax, deasphalted oil, hydrotreated wax, hydrotreated residual oil, crude oil, and have a boiling point higher than 320 ℃.

3. The method for preparing ethylene by catalytic conversion of petroleum hydrocarbon as claimed in claim 1, wherein the light hydrocarbon (R22) is one or a mixture of naphtha, C4, C5, hydrogenated catalytic cracking diesel components.

4. The process for the production of ethylene by the catalytic conversion of petroleum hydrocarbons as claimed in claim 1, wherein the heavy oil is replenished or the oil is recycled at any of 1 to 3 locations of the upper reaction zone (R28) downstream of the second reactor (R20), the stripping section (S10) and the reactor (R10).

5. A process for the production of ethylene by the catalytic conversion of a petroleum hydrocarbon as claimed in claim 1, wherein the regenerator (G10) has a dilute phase zone (G15) below which two upper and lower regeneration zones, a lower regeneration zone (G19) and an upper regeneration zone (G12), are disposed, and wherein the regenerator is supplied to the reactor (R10) and the second reactor (R20) via the upper regeneration zone (G12).

6. The device for preparing the ethylene by the catalytic conversion of the petroleum hydrocarbon is characterized in that a reactor (R10), a second reactor (R20), a regenerator (G10), a settler (D10) and a stripping section (S10) are arranged, the regenerator (G10) and the settler (D10) are arranged in parallel, and the device is characterized in that:

the second reactor (R20) shares a settler (D10), a stripping section 10 and a regenerator (G10) with the reactor (R10); a heavy petroleum hydrocarbon inlet (R12A) is arranged at the lower part of the reactor (R10); a regenerant inlet (R14A) at the lower part of the reactor (R10) is communicated with a regenerant outlet (G14A) of the regenerator (G10) through a regeneration vertical pipe (G14),

the second reactor (R20) comprises a lower reaction zone (R27) at the lower part and an upper reaction zone (R28) at the upper part, the lower reaction zone (R27) is used for low-temperature catalytic cracking reaction, and the upper reaction zone (R28) is used for high-temperature ethylene cracking reaction; a light hydrocarbon inlet is arranged at the lower part of the lower reaction zone (R27); the lower regenerant inlet (R34A) at the lower portion of the lower reaction zone (R27) is in communication with the lower regenerant outlet (G34A) of the regenerator (G10) through a lower regeneration riser (G34), and the upper regenerant inlet (R24A) at the lower portion of the upper reaction zone (R28) is in communication with the upper regenerant outlet (G24A) of the regenerator (G10) through an upper regeneration riser (G24).

7. An apparatus for producing ethylene by catalytic conversion of petroleum hydrocarbon according to claim 6, wherein the regenerator (G10) has a dilute phase zone (G15) below which an upper and a lower regeneration zones (lower regeneration zone (G19) and upper regeneration zone (G12) are disposed, and the regenerant outlet (G14A), the lower regenerant outlet (G34A) and the upper regenerant outlet (G24A) are disposed in the upper regeneration zone (G12).

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