Method for preparing ethylene and propylene by means of fluid catalytic conversion

Abstract

The present invention belongs to the technical field of fluid catalytic conversion, and relates to a method for preparing ethylene and propylene by means of fluid catalytic conversion. In the method, an upstream-downstream combined reactor is used, reaction raw materials are selectively cracked during an upstream reaction process and a downstream reaction process respectively by means of the arrangement of the reaction raw materials, and stable or delayed coking and removal of high-temperature cracking products are achieved during the reaction processes, thereby both achieving high yields of ethylene and propylene and avoiding the situation of equipment being incapable of implementing long-period operation due to coking; moreover, since the reactor is in the form of a folding reactor, construction investments are reduced. The method of the present invention is suitable for treating hydrocarbon compounds or hydrocarbons, particularly petroleum hydrocarbons, and liquefied waste plastics, and olefins are prepared by means of catalytic cracking.

Description

A method for preparing ethylene and propylene by fluidized catalytic conversion Technical Field

[0001] The present invention relates to the technical field of catalytic conversion, in particular to a method for preparing ethylene and propylene by fluidized catalytic conversion, wherein the reaction raw materials are hydrocarbons or hydrocarbons, especially petroleum hydrocarbons, or liquefied waste plastics. Background Art

[0002] Light olefins, represented by ethylene and propylene, are essential raw materials for the chemical industry. Existing catalytic conversion technologies produce these olefins as byproducts during gasoline and diesel production, far from meeting the current market demand for organic chemical raw materials. Aromatic hydrocarbons are a key organic chemical raw material second only to ethylene and propylene in terms of production and scale. Their derivatives are widely used in the production of chemical fibers, plastics, rubber, and other chemical products, as well as fine chemicals. With the continuous development of the petrochemical and textile industries, global demand for aromatic hydrocarbons is also growing. Light olefins are produced primarily domestically and internationally through steam cracking in ethylene complexes, using natural gas or light petroleum fractions as feedstock. This produces significant quantities of other essential raw materials, including other olefins and aromatics, as byproducts. Despite decades of development and continuous improvement, steam cracking technology remains limited by high energy consumption, high production costs, high CO2 emissions, and difficulty in adjusting product structure. Traditional steam cracking technology for ethylene and propylene production is facing significant challenges. Using catalytic conversion to produce light olefins, while simultaneously producing propylene, butenes, and other chemical raw materials, such as aromatics, offers a new approach to addressing resource shortages and achieving low-cost production of chemical products, and has become a significant research topic and hot topic. In addition, due to the widespread use of plastics, plastics that take 500 to 1,000 years to decompose often cause large-scale if pollution. Liquefying waste plastics and then cracking them to produce propylene is also a direction of plastic recycling.

[0003] Catalytic cracking technicians know that the propylene yield of catalytic cracking can only be around 20%. Increasing the ethylene yield as much as possible is the main goal of catalytic cracking to produce olefins, the core of improving the economic efficiency of catalytic cracking, and the key to whether fluidized catalytic cracking can compete with steam cracking. The bottleneck problem of catalytic cracking to produce ethylene is the "long-cycle operation" problem. As we all know, petrochemical industry is a large-scale chemical industry, which mainly relies on scale to improve its economic competitiveness. The scale of steam cracking equipment is 2 million tons / year of olefins, and the economic scale of catalytic cracking and propylene production must also be above 3 million tons / year of raw material processing capacity. Long-cycle operation is the key to economic benefits or whether the technology can be applied. For such a large-scale device, any technology that cannot operate continuously and smoothly is not feasible.

[0004] Catalytic cracking to produce ethylene and propylene is a hot topic both domestically and internationally. Almost all major oil conglomerates have invested heavily in its development, and relevant universities are also paying close attention. Various routes, including catalytic cracking of light hydrocarbons, heavy oil, and crude oil, have received significant attention. Catalytic cracking to produce ethylene and propylene is not a new idea. HCC has been experimenting with heavy oil catalytic cracking to produce ethylene for many years, and CPP has also sought to maximize propylene yields. KBR has developed ACO / K-COT light hydrocarbon fluidized catalytic cracking technology for ethylene and propylene, which has entered industrial application. The China University of Petroleum is developing UPC technology for olefins from crude oil catalytic cracking and is currently conducting industrial trials. Tsinghua University proposed a multi-stage descending reaction technology in ZL201810646036.5. In summary, the main technical routes for producing ethylene and propylene through fluidized catalytic cracking include a dual-riser route and a dual-descent reaction route. Professor Zhang Jianfang of the China University of Petroleum proposed a multi-stage riser (upstream) cascade reaction (with catalyst separation in the middle) in 1999, while Tsinghua University has proposed a multi-stage descending cascade route (with catalyst separation in the middle). Technical issues

[0005] Since components below C2 (including C2) mainly come from free radical reactions, high temperatures are required to produce high ethylene content, such as steam cracking reaction temperatures above 800°C. Catalytic cracking to produce olefins, especially catalytic cracking with high ethylene yield targets, still requires relatively high reaction temperatures, generally above 630°C, to produce the required ethylene. The bottleneck problem faced by high-temperature catalytic cracking to produce ethylene and propylene is the long-term operation cycle. The main problem affecting long-term operation is "coking of some oil and gas processing equipment after the catalytic cracking reaction."

[0006] Existing technologies quench the product oil and gas after the reactor settler, but this does not truly address the long cycle time required to meet high ethylene yield requirements. To date, only KBR's ACO / K-COT catalytic cracking system has achieved truly high olefin yields of 40% for both ethylene and propylene, and this system still faces challenges in achieving long cycle times. Therefore, it can be said that there is no truly successful, viable catalytic cracking technology for producing ethylene and propylene with high olefin yields. This long cycle time has become a bottleneck, and the patents and technical solutions available do not yet offer a sound solution. Technical Solutions

[0007] Summary of the Invention

[0008] The object of the present invention is to provide a method for producing ethylene and propylene by fluidized catalytic conversion. Specifically, a reaction method is provided in which the reaction raw materials are reorganized and selectively cracked according to different targets. This method not only achieves the target of high ethylene and propylene yields, but also facilitates long-term operation and reduces construction investment.

[0009] The technical solutions of the present invention are as follows:

[0010] The method for preparing ethylene and propylene by fluidized catalytic conversion of the present invention comprises a raw material reaction and catalyst regeneration section. In one embodiment, a method for preparing ethylene and propylene by fluidized catalytic conversion comprises a reaction section provided with one or more reactors, at least one of which is designed as a continuous up-down and down-down combined folded form, i.e., an up-down and down-down combined reactor or a folded reactor is used. When an up-down and down-down combined reaction is carried out in the up-down and down-down combined reactor, the reactant flow and the catalyst continuously pass through the up-down reaction section (commonly known as a riser form) and the down-down reaction section, and the two sections are operated at different temperatures and with different product targets. The reaction raw materials of at least one reactor are composed of two parts according to different targets, one part is used to maximize the ethylene yield, and the other part is used to target propylene and ethylene (primarily propylene, with ethylene as a secondary target). The up-down reaction section is used to increase the yield of ethylene. and propylene yields, and the main purpose of the downstream reaction part is to operate for a long period of time; a part of the reaction raw materials, as raw materials for ethylene, undergo high-temperature catalytic cracking reaction at a higher temperature in the upstream part of the reactor to achieve high ethylene and propylene yield targets, and then enter the downstream part of the reactor together with the catalyst for reaction; another part of the reaction raw materials, as raw materials mainly composed of propylene and also producing ethylene, reacts in the downstream part at a slightly lower reaction temperature. In one embodiment, the other part of the reaction raw materials enters the reactor downstream (or above, i.e., downstream on the process stream) of the upstream reaction part, or enters the reactor at the connecting part of the upstream and downstream combined reactor, or enters the reactor in the downstream reaction part, and reacts under the condition of reduced temperature; in one embodiment, the upstream and downstream combined reaction process, i.e., the upstream and downstream components and reactions, are carried out according to the following process:

[0011] (1) The up-down combined reactor is provided with an up-down portion (commonly known as a riser) and a down-down portion, and the two portions form a whole. In one embodiment, the reaction raw materials of the up-down combined reactor are divided into a first reaction raw material in a first portion and a second reaction raw material in another portion. The up-down portion is used for catalytic cracking of the first reaction raw material at a higher temperature to produce ethylene and propylene. The down-down portion chemically stabilizes the catalytic cracking products of the up-down portion to achieve delayed removal of coke from the up-down reaction products. The down-down portion simultaneously completes catalytic cracking of the second reaction raw material at a lower temperature relative to the first reaction raw material to produce propylene and ethylene. In one embodiment, the up-down portion can be a constant diameter riser or a variable diameter riser. The riser form is a common technology and is mastered by technical personnel.

[0012] (2) The first reaction raw material with high ethylene content as the target enters the up-and-down combined reactor at the lower part or bottom area of ​​the up-and-down section. The catalyst from the regenerator first enters the up-and-down section through the catalyst tube and the catalyst inlet tube, contacts with the first reaction raw material to undergo catalytic cracking reaction while flowing upward. Then, the reaction product / catalytic cracking product and the catalyst are turned and enter the down-and-down section together, where the product is stabilized under mild conditions. The reaction temperature in the up-and-down section is controlled by a catalyst slide valve provided between the catalyst tube and the catalyst inlet tube.

[0013] Alternatively, in one embodiment, the catalyst from the regenerator enters the upward section in two ways through the catalyst tube and the catalyst inlet tube, and the upper catalyst tube C and the catalyst inlet tube C, respectively. In specific implementation, the upward section is provided with two catalyst circulations from the regenerator, the lower one entering the reactor through the catalyst inlet tube and the catalyst slide valve, and the upper one entering the reactor through the catalyst inlet tube C and the catalyst slide valve C;

[0014] In one embodiment, the catalyst from the regenerator first enters the regeneration agent stripper, where it is fluidized by steam to displace the carried non-condensable gases such as N2, CO2, CO, and O2 from the regenerator, which are well known to technicians in the regeneration catalyst stripping process;

[0015] The first reaction raw material or a mixture of the first reaction raw material and steam, or the first reaction raw material is atomized with steam and then enters the ascending part; catalytic cracking requires steam dilution, and steam is separated or mixed with the raw material before entering the reactor, which is familiar to technicians;

[0016] (3) The second reaction raw material enters the combined up-and-down reactor at the upper end of the downstream section, or enters the reactor at the connecting section or section between the downstream section and the upstream section, or first enters the reactor at the upper or downstream portion of the upstream section and then enters the downstream section; the second reaction raw material is catalytically cracked in the downstream section, with propylene as the primary target and ethylene as a secondary target; the flow rate of the second reaction raw material can be adjusted according to the reaction temperature range limited by the downstream section, which is mainly propylene with a secondary requirement for ethylene;

[0017] (4) The flow of the first reaction raw material and the second reaction raw material after the reaction is separated into gas and solid in the reaction settler, and the reaction product after the catalyst is separated flows out of the reaction settler from the product outlet of the reaction settler; the separated catalyst settles to the stripping section below, and the stripped catalyst enters the regenerator from the spent catalyst pipe and the spent catalyst inlet pipe of the regenerator for regeneration, and after regeneration, enters the upward part of the upward and downward combined reactor for recycling.

[0018] In one embodiment, it is a common practice to set up multiple reactors according to the amount of raw materials or the properties of different raw materials. In particular, when some non-ethylene and propylene components in the cracking product need to be recycled, it is customary to set up independent reactors for the recycled components. When multiple reactors are set up, gas-solid separation is performed in the same reaction settler, or gas-solid separation is performed in different reaction settlers.

[0019] In one embodiment, the reaction settler is provided with one or two stages of cyclone separators in series for gas-solid separation, which is well known to technicians; the cyclone separators are one or more stages in series, and each stage is composed of multiple cyclone separators in parallel, which is well known to technicians.

[0020] In one embodiment, the descending part of the up-downward combined reactor enters the reaction settler downward from the top of the reaction settler, and the outlet is vertically downward. The catalyst in the reactor flows downward at the outlet of the descending part, and the momentum formed by the gravity of the catalyst and the downward flow velocity is used to achieve the first stage of gas-solid separation; the gas and part of the catalyst then flow upward in the opposite direction and enter the cyclone separator for further gas-solid separation.

[0021] In one embodiment, a gas passage tube is disposed around the periphery of the descending section. Gas and a portion of the catalyst flowing out of the descending section outlet flow upward into the annular gap / channel between the gas passage tube and the descending section, and then into the cyclone separator, or from the annular gap through the outlet tube into the cyclone separator. The stripping steam in the stripping section and the oil and gas removed thereby also flow into the annular gap between the gas passage tube and the descending section. In one embodiment, the lower end of the gas passage tube is at a higher elevation than the descending section outlet.

[0022] In one embodiment, a cyclone separator is provided outside the outlet of the descending portion, and a gas channel tube is provided outside the cyclone separator; the catalyst separated by the cyclone separator is gravity-precipitated to the stripping section below, and the gas and part of the catalyst flow upward in the annular gap between the gas channel tube and the descending portion and enter the cyclone separator, or enter the cyclone separator from the annular gap through the outlet tube, which is well known to technicians skilled in the art.

[0023] In one embodiment, the descending portion of the up-downward combined reactor is outside the reaction settler, and the lower end outlet of the descending portion turns to enter the reaction settler, and gas-solid separation is performed in the reaction settler.

[0024] In one embodiment, an up-and-down combined reactor is provided with two parallel up-flow parts, an up-flow part and an up-flow part B, and a common down-flow part, that is, two up-flow parts and a common down-flow part are provided; the first reaction raw material is first subjected to catalytic cracking in the up-flow part, and then turns together with the catalyst to enter the down-flow part for further catalytic cracking; the reaction raw material of the up-flow part B is first subjected to catalytic cracking reaction in the up-flow part, and then reacts together with the logistics from the up-flow part in the down-flow part, specifically, the reaction raw material of the reactor B is first subjected to catalytic cracking reaction in the up-flow part B, and then enters the down-flow part, is mixed with the reaction product and catalyst from the up-flow part, and continues to catalytic cracking in the common down-flow part; the second reaction raw material enters the reactor for reaction in the down-flow part, or enters the reactor in the connecting section of the down-flow part and the up-flow part and / or the up-flow part B, or enters the reactor downstream or upstream of the up-flow part or / and the up-flow part B.

[0025] In one embodiment, the upstream part is provided with two catalyst circulations from the regenerator, and the catalyst from the regenerator is first steam stripped in the regeneration agent stripper and the regeneration agent stripper C, respectively, and then enters the up-down combined reactor through the catalyst tube and the catalyst inlet tube, and the catalyst tube C and the catalyst inlet tube C, respectively; the second reaction raw material enters the up-down combined reactor above / upper part of the upper catalyst inlet tube C (or downstream, i.e., downstream in the process flow), or enters the up-down combined reactor in the connecting section between the upstream part and the down-down part, or enters the up-down combined reactor in the down-down part.

[0026] In one embodiment, the reaction temperature of the upstream part of the up-and-down combined reactor is higher than the reaction temperature of the downstream part, the reaction temperature of the first reaction raw material in the upstream part is 600°C-720°C, and the reaction time is 1.0 second-10.0 seconds; the reaction temperature of the downstream part is 570°C-670°C, and the reaction time is 1.0 second-7.0 seconds; the reaction pressure is 80kPa-200kPa (table); because catalytic cracking is an endothermic reaction, the temperature at different positions in the reactor is different during the reaction process, and the reaction temperature is the outlet zone temperature of the corresponding reaction according to the practice of the fluidized catalytic cracking / cracking industry, and the pressure is the settler pressure outside the reactor outlet.

[0027] In one embodiment, the first reaction raw material and the second reaction raw material are of the same or different natures; when the first reaction raw material and the second reaction raw material are of different natures, the first reaction raw material is a raw material with a low actual boiling point or low density, and the second reaction raw material is a raw material with a high actual boiling point or high density.

[0028] In one embodiment, the first reaction raw material and / or the second reaction raw material is a petroleum hydrocarbon raw material, or a hydrocarbon, or a hydrocarbon, or a petroleum hydrocarbon and methanol, or a mixture of multiple raw materials, or multiple raw materials fed separately; when multiple raw materials are used, they can be fed into the reactor separately; when the first reaction raw materials have different actual boiling points, the raw material with the lower actual boiling point preferentially enters the reactor at the bottom to contact and react with the catalyst first. In one embodiment, the first reaction raw material and / or the second reaction raw material is liquefied waste plastic.

[0029] In one embodiment, when the reaction raw materials include raw materials with a true boiling point lower than 200° C., they are fed into the reactor as the first reaction raw materials in the upward portion.

[0030] In one embodiment, when there is a raw material with a true boiling point lower than 200° C. in the first reaction raw materials, it is preferentially vaporized before entering the reactor.

[0031] In one embodiment, the first reaction raw material and the second reaction raw material are petroleum hydrocarbon raw materials, or a mixture of petroleum hydrocarbon and steam, or a material atomized by steam.

[0032] In one embodiment, the second reaction raw material is a raw material having a true boiling point higher than 300° C. in an amount of 90% or more by mass.

[0033] In one embodiment, when the C4 and light gasoline components in the cracking products need to be recycled, they are recycled in an independent reactor, or recycled as part of the first reaction feed.

[0034] In one embodiment, the reactor B reaction raw material may be the same as or different from the first reaction raw material, and the upstream portion B reaction raw material may be the same as or different from the first reaction raw material.

[0035] In one embodiment, the catalyst can be a catalyst containing ZSM-5 molecular sieve, a catalyst containing modified ZSM-5 molecular sieve, a metal oxide, an alkaline earth oxide, a heat carrier, a mixture of multiple catalysts, etc. The catalyst does not affect the specific implementation of this method.

[0036] In one embodiment, when the regeneration of hydrocarbons or hydrocarbon-based coke to produce ethylene and propylene is insufficient to provide the heat required for the reaction, heat is supplemented to the reaction system by adding fuel to the regenerator.

[0037] In one embodiment, one or more reactors are provided, and at least one reactor is provided in an up-and-down folded form, i.e., an up-and-down combination form. The folded reactor, or folded reactor, i.e., an up-and-down combination reactor, comprises at least two vertical reaction sections and a transverse connecting section, wherein the length or total height of the upward vertical reaction section (upward portion) is greater than that of the downward vertical reaction section (downward portion), the vertical reaction section and the transverse connecting section are connected by a bend connection or a tee connection, the reactor outlet is connected downward or laterally to the gas-solid separator, the catalyst enters the reactor in the upward vertical reaction section, and the catalyst enters the reactor in the upward vertical reaction section; the reactor is provided with 1-3 catalyst inlets. In one embodiment, the diameters of the various parts of the folded reactor may be equal, or different diameters or a tapered combination may be used. The use of different diameter combinations according to the needs of the reactants is a common engineering design, which is mastered by technical personnel.

[0038] In one embodiment, a portion of the catalyst is separated from the upstream portion and / or the upper portion of the upstream portion B, and the remaining catalyst continues to react downstream. Specifically, a catalyst outlet is provided at the upper portion of the upstream portion, and a portion of the catalyst is separated from the upstream portion, while a portion of the catalyst and oil gas is retained for continued use in the downstream portion, thereby reducing the catalyst-to-oil ratio and heat supply of the downstream reaction. In one embodiment, 50%-85% of the catalyst is separated from the upstream portion. The catalyst separated from the upstream portion of the reactor enters the regenerator, or enters the stripping section for stripping before entering the regenerator.

[0039] In one embodiment, when multiple reactors are provided, one reaction settler or multiple reaction settlers are provided; there are many actual cases of multiple reaction settlers, which are well known to technicians. Beneficial effects

[0040] Beneficial effects of the present invention:

[0041] The method of the present invention achieves simultaneous high-temperature cracking to produce ethylene and catalytic cracking of a portion of the raw materials to produce propylene and ethylene during the reaction process through optimized rearrangement of the reaction raw materials. Simultaneously, the high-temperature cracking to produce ethylene product achieves stable and delayed coke removal during the reaction process, achieving high ethylene yield requirements while effectively resolving the problem of long-term operation due to high-temperature cracking and product instability. The present invention fully utilizes the temperature of the reaction products to achieve low-energy catalytic cracking to produce olefins and optimize products. Simultaneously, the present invention optimizes the reaction structure and improves olefin yield without increasing construction investment. The present invention forms a combined solution, increasing reaction and product selectivity and improving efficiency. The present invention is particularly suitable for mixed catalytic cracking of light and heavy components. In previous technical routes, catalytic cracking with high ethylene yield requirements, to achieve stable and delayed coke removal of the ethylene production reaction product, has been achieved through "quenching." While "quenching" has long been available, it is impossible to achieve "quenching" in high-temperature catalytic cracking technologies targeting ethylene without separating a portion of the catalyst. The heat content of the reactants is too high, and the amount of quenching raw material required may even be higher than the reaction raw material. Furthermore, in the past, the purpose of "quenching" was to terminate the reaction, and the quenching medium was not considered for the reaction, resulting in pure energy consumption. If the second reaction raw material is fed, reaction time is required, and the temperature of the first reaction raw material product and the delayed removal of coke also require time, making "quenching" at the reactor outlet useless. In fact, if the conventional scheme is used to achieve normal cracking of the second reaction raw material and the desired stability of the upstream reaction, the height of the equipment construction would need to be doubled, which is not feasible in engineering terms. The present invention solves the above problems.

[0042] The folding reactor of the present invention can simultaneously exert the advantages of upward reaction and downward reaction in one reactor, and the folding structure greatly reduces investment and improves economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic diagram of an apparatus according to Embodiment 1 and Embodiment 3 of the present invention;

[0044] FIG2 is a schematic diagram of a device according to embodiment 2 of the present invention;

[0045] FIG3 is a schematic diagram of a device according to embodiment 4 of the present invention;

[0046] FIG4 is a schematic diagram of a device according to embodiment 5 of the present invention;

[0047] FIG5 is a schematic diagram of a device according to embodiment 6 of the present invention;

[0048] FIG6 is a schematic diagram of a device according to embodiment 7 of the present invention.

[0049] The numbered marks in the figure are as follows:

[0050] 10: Up-down combined reactor, 10B: Reactor B; 11: Bottom diameter expansion portion of the (up-down combined reactor); 12: Up-down portion, also known as the up-down combined reactor up-down portion, or the up-down reaction portion; 12B: Up-down portion B, also known as the up-down combined reactor up-down portion B, or the up-down reaction portion B; 13: Down-down portion, also known as the down-down combined reactor down-down portion, or the down-down reaction portion; 14: Cyclone separator, also known as the gas-solid cyclone separator at the outlet of the down-down portion of the (up-down combined reactor); 15: Connecting section (connecting section of the up-down combined reactor), 15B: Connecting section B; 16: Catalyst inlet pipe, 16B: Catalyst inlet pipe B, 26: Catalyst inlet pipe C; 17: Catalyst slide valve, 17B: Catalyst slide valve B, 27: Catalyst slide valve C, 37: Catalyst slide valve D; 18: Inner pipe, also known as the inner reaction pipe, or the inner reaction pipe for the reaction raw materials at the bottom of the up-down combined reactor; 19: Turning connecting section;

[0051] 20 reaction settler, 21 spent catalyst pipe, 22 cyclone separator, 23 stripping section, or stripper; 24 gas channel pipe, also called channel pipe or gas outlet channel pipe; 25 annular gap; 25B ​​outlet pipe, also called gas upflow channel; 28 reaction settler product outlet; 30 regenerator, 31 regenerator catalyst outlet, 36 spent catalyst inlet pipe entering the regenerator;

[0052] 40 regenerant stripper, 40B regenerant stripper B; 46 catalyst tube (from the regenerator), 46B catalyst tube B (from the regenerator), 46C catalyst tube C (from the regenerator);

[0053] 50 crude oil separation tower, 51 crude oil flow (entering the crude oil separation tower), 54 heavy components separated from the crude oil, 55 light components and other gases separated from the crude oil; 60 heat exchanger;

[0054] F0 crude oil, F11 steam; F12 first reaction raw material, used for the upper reaction raw material, or called the bottom reaction raw material of the upper and lower combined reactor; F12B upper reaction raw material B; F13 second reaction raw material, used or mainly used for the lower reaction raw material; F14 reaction product, the reaction product after the catalyst is separated; F15 reactor B reaction raw material;

[0055] C4 hydrocarbons with a carbon number of 4, FRC flow metering control signal, TIC temperature measurement control signal, and other steam are not marked. Injecting steam into the reactor during implementation is a conventional requirement and is not shown in detail in the figure. Best Mode for Carrying Out the Invention

[0056] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, in order to help readers better understand the spirit of the present invention. However, the protection scope of the present invention includes but is not limited to this.

[0057] Example 1:

[0058] The apparatus shown in FIG1 is used to implement the fluidized catalytic conversion method for producing ethylene and propylene of the present invention. An up-and-down combined reactor 10, a reaction settler 20, and a regenerator 30 are provided. The up-and-down combined reactor 10 is in a folded form and includes an upward vertical reaction section, i.e., an upward portion 12, and a downward vertical reaction section, i.e., a downward portion 13. The two parts form a whole. The upward portion 12 adopts a riser of equal diameter; the total height of the upward vertical reaction section is greater than that of the downward vertical reaction section, and the vertical reaction section and the horizontal connecting section 15 are connected by a bend. In specific implementation, the connecting section 15 can also be connected by a tee; the downward portion 13 enters the reaction settler 20 from the top of the reaction settler downward, and the outlet is vertically downward;

[0059] The reaction raw materials include two parts, the first reaction raw material F12 is naphtha and / or recycled pyrolysis gasoline, a hydrogen content of 15.3%, the second reaction raw material F13 is diesel, a hydrogen content of 13.8%, the properties of the first reaction raw material F12 are shown in Table 1, the properties of the second reaction raw material F13 are shown in Table 2; in the present invention, including the various embodiments, including the% unless otherwise specified represent mass percentage, ie m%;

[0060] Steam F11 enters the reactor from the bottom, and the first reaction feed F12 enters the reactor in the lower area of ​​the ascending portion 12; the catalyst from the regenerator 30 flows through the regenerator catalyst outlet 31 and enters the regeneration agent stripper 40. After the steam replaces the carried non-condensable gases such as N2, CO2, CO, and O2 from the regenerator, it enters the ascending portion 12 through the catalyst tube 46 and the catalyst inlet tube 16, mixes upward with the first reaction feed F12, and undergoes a catalytic cracking reaction. At the same time, it flows upward, and the catalytic cracking products and catalyst are turned and enter the descending portion 13 together, and the products are stabilized under mild conditions; the second reaction feed F13 enters the reactor at the upper end of the descending portion 13 and undergoes catalytic cracking in the descending portion 13;

[0061] The stream after the reaction of the first reaction raw material F12 and the second reaction raw material F13 undergoes gas-solid separation in the reaction settler 20, and the reaction product F14 after the catalyst is separated flows out of the reaction settler through the product outlet 28 of the reaction settler; the separated catalyst settles to the stripping section 23 below, and the stripped catalyst enters the regenerator 30 through the spent catalyst pipe 21 and the spent catalyst inlet pipe 36 for regeneration, and after regeneration, enters the upstream section 12 of the up-down combined reactor 10 for recycling;

[0062] Fuel oil was added to the dense phase fluidized bed section of regenerator 30, with the fuel oil quantity controlled based on a regeneration temperature of 740°C. The reaction temperature in the ascending section 12 was 670°C, the reaction time was 3 seconds, and the steam ratio was 40%. The reaction temperature in the descending section 13 was 635°C, the reaction time was 3 seconds, and the steam ratio was approximately 35%. The pressure in the reaction settler was 120 kPa (gauge pressure). The catalyst was a metal oxide. The product distribution of Example 1 is shown in Table 3 (relative to the total feed, excluding recycled material). Modes for Carrying Out the Invention

[0063] The following are other embodiments of the present invention.

[0064] Example 2: The apparatus shown in FIG2 is used to implement the method for producing ethylene and propylene by fluidized catalytic conversion of the present invention:

[0065] An up-and-down combined reactor 10, a reaction settler 20, and a regenerator 30 are provided; a descending portion 13 of the up-and-down combined reactor 10 is outside the reaction settler 20, and a lower end outlet of the descending portion turns to enter the reaction settler 20, where gas-solid separation is performed, and a turning connection section 19 is provided at the turning point;

[0066] A reactor bottom expansion section 11 is provided at the bottom of the ascending section 12. Steam F11 enters the reactor from the bottom, mixes with the catalyst entering through the catalyst tube 46 and the catalyst inlet tube 16, and the C4 components introduced into the reactor, and flows upward in the reactor bottom expansion section 11, where it contacts and mixes with the first reaction feed F12 to undergo catalytic cracking. The second reaction feed F13 enters the reactor at the connecting section 15.

[0067] The first reaction feedstock F12 uses naphtha and recycled light gasoline as raw materials, with a C4 olefin content of 78%, a naphtha hydrogen content of 15.3%, and a recycled light gasoline final boiling point of 88°C. C4 and recycled light gasoline are recycled parts separated from the cracking products of this unit, with C4 accounting for 12% of the naphtha feedstock and recycled gasoline accounting for 10% of the naphtha feedstock. The second reaction feedstock F13 is atmospheric heavy oil with a hydrogen content of 13%. Its composition is shown in Table 4.

[0068] The reaction conditions were as follows: reaction temperature of 665°C, reaction time of 2.5 seconds, and a steam ratio of 45% relative to the naphtha in the upstream portion 12 of the reactor; reaction temperature of 600°C, reaction time of 3.5 seconds, and a steam ratio of 35% relative to the total feed in the downstream portion 13; and a settler pressure of 115 kPa (Table). All other conditions were the same as in Example 1. The product distribution of Example 2 is shown in Table 5 (relative to the total feed).

[0069] Example 3:

[0070] The apparatus shown in Figure 1 was used to implement the fluidized catalytic conversion method for producing ethylene and propylene according to the present invention. The reaction feedstock consisted of two components: the first reaction feedstock F12 and the second reaction feedstock F13, both of which were atmospheric heavy oil from the Qingyang Oilfield, with a hydrogen content of 12.8%. The first reaction feedstock F12 accounted for 70% of the total reaction feedstock, while the second reaction feedstock F13 accounted for 30%. The reaction temperature for the first reaction feedstock F12 was 630°C, the reaction time was 3.5 seconds, and the reaction temperature for the second reaction feedstock F13 was 605°C, the reaction time was 3.5 seconds. The pressure in the reactor was 110 kPa (table), and the steam usage in the reactor was 35% of the total reaction feedstock. The catalyst was a mixture of metal oxides and a catalyst containing 35% ZSM-5 molecular sieve. All other components were the same as in Example 1. The product distribution of Example 3 is shown in Table 6 (excluding cracking product recycling). Example 4:

[0071] The apparatus shown in FIG3 is used to implement the method for producing ethylene and propylene by fluidized catalytic conversion of the present invention:

[0072] An up-and-down combined reactor 10, a reaction settler 20, and a regenerator 30 are provided; a reactor bottom diameter expansion portion 11 is provided at the bottom of the up-and-down portion 12, and an inner reaction tube or inner tube 18 is provided in the reactor bottom diameter expansion portion 11;

[0073] C4 first reacts in the fluidized bed area outside the inner tube 18, then flows upward into the ascending portion 12, where it mixes with the first reaction raw material F12 as an intermediate reactant and continues to react. The first reaction raw material F12 first enters the inner tube 18 from the bottom of the reactor, and the catalyst after reacting with C4 enters the inner tube 18 from the bottom to react with the first reaction raw material F12. The reaction products and catalyst flow upward out of the inner tube 18, mix with the C4 reaction products, and enter the ascending portion 12 to continue to react.

[0074] The ascending section 12 is provided with two catalyst circulations from the regenerator 30. The catalyst from the regenerator 30 is first steam stripped in the regeneration agent stripper 40 and enters the bottom diameter expansion section 11 of the reactor through the catalyst tube 46 and the catalyst inlet tube 16 as the first catalyst, and first reacts with C4. The catalyst after the reaction with C4 enters the inner tube 18 from the bottom and reacts with the first reaction raw material F12. The reaction product and catalyst flow upward out of the inner tube 18, mix with the C4 reaction product and enter the ascending section 12 to continue the reaction.

[0075] The second regenerated catalyst enters the reactor upstream portion 12 from the catalyst inlet pipe C26. In practice, this catalyst is either directly introduced from the regenerator 30 via the catalyst pipe C46C into the upstream portion 12, or first stripped with steam in a regeneration agent stripper C (not shown) connected to the regenerator 30 and then introduced into the upstream portion 12 via the catalyst pipe C46C.

[0076] The second reaction feedstock F13 enters the reactor above the catalyst inlet pipe C26;

[0077] The descending portion 13 flows downward from the top of the reaction settler into the reaction settler 20, with the outlet pointing vertically downward. A gas passage tube 24 is provided on the periphery of the descending portion 13, with the lower end of the gas passage tube 24 at a higher elevation than the outlet of the descending portion 13. The gas and part of the catalyst flowing out of the outlet of the descending portion 13 flow upward into the annular gap 25 between the gas passage tube 24 and the descending portion 13, and then enter the cyclone separator 22 for gas-solid separation.

[0078] The first reaction raw material F12 is light naphtha with a hydrogen content of 16%. The second reaction raw material F13 is atmospheric heavy oil from Qingyang Oilfield with a hydrogen content of 12.8%. C4 is recycled self-produced components.

[0079] The reaction temperature in the reactor's upstream section 12 below the second regeneration agent inlet, i.e., the catalyst inlet pipe C26, was 630°C for a reaction time of 2 seconds. The reaction temperature in the reactor's upstream section 12 above the second regeneration agent inlet was 615°C for a reaction time of 1.5 seconds. The reaction temperature in the downstream section 13 was 600°C for a reaction time of 2.5 seconds. All other components were the same as in Example 1. Example 5:

[0080] The apparatus shown in FIG4 is used to implement the method for producing ethylene and propylene by fluidized catalytic conversion of the present invention:

[0081] An up-down combined reactor 10, a reaction settler 20 and a regenerator 30 are provided;

[0082] The descending portion 13 flows downward from the top of the reaction settler into the reaction settler 20, with the outlet pointing vertically downward. A cyclone separator 14 is disposed outside the outlet of the descending portion. A gas passage pipe 24 is disposed outside the cyclone separator 14, and an outlet pipe 25B is provided between the gas passage pipe 24 and the inlet of the first-stage cyclone separator. The gas and a portion of the catalyst flowing out of the outlet of the descending portion 13 first enter the cyclone separator 14 for gas-solid separation. The catalyst separated by the cyclone separator 14 gravity-settles to the stripping section 23 below. The gas and a portion of the catalyst flow upward through the annular gap 25 between the gas passage pipe 24 and the descending portion 13, and then enter the cyclone separator 22 through the outlet pipe 25B for gas-solid separation.

[0083] The first reaction raw material F12 is a light crude oil component, and the second reaction raw material F13 is a heavy crude oil component. Crude oil F0 is heated to 280-320°C in a heat exchanger 60 and, as crude oil stream 51, is separated into a gaseous light component and a heavy component in a two-component separation tower, i.e., a crude oil separation tower 50. The gaseous light component, i.e., the light crude oil component or the light components and other gases 55 separated from the crude oil, partially or entirely enters the reactor from the bottom as the first reaction raw material F12. The heavy component 54 separated from the crude oil, i.e., the heavy crude oil component, enters the reactor above the catalyst inlet pipe C26 as the second reaction raw material F13.

[0084] The hydrogen content of crude oil F0 was 13.0%; the light component C4 was heated to 50° C. and entered the reactor; the rest was the same as in Example 4. Example 6:

[0085] The apparatus shown in FIG5 is used for fluidized catalytic conversion to produce ethylene and propylene, and is provided with a regenerator 30, a reaction settler 20, an up-and-down combined reactor 10, and a reactor B10B. The reactor B10B is a riser reactor.

[0086] The two reactors share a reaction settler 20, and the dilute phase pressure of the reaction settler is 120 kPa. In specific implementation, the outlet of the reactor B10B can be directly connected to the cyclone separator 22, and the reaction products and catalyst of the reactor B enter the cyclone separator for gas-solid separation. The outlet of the reactor B10B can also be connected to the gas channel pipe 24. The reaction products and catalyst of the reactor B first enter the annular gap 25 between the gas channel pipe 24 and the descending portion 13, and then enter the cyclone separator 22 through the annular gap 25 through the outlet pipe 25B for gas-solid separation. In this embodiment, the outlet of the reactor B10B is connected to the gas channel pipe 24.

[0087] The regeneration temperature is 735°C; a regeneration agent stripper 40 and a regeneration agent stripper B40B are provided from the regenerator 30. The catalyst from the regenerator first enters the catalyst stripper, and after the N2, CO2, CO, O2 and other gases carried by the catalyst are replaced by steam, it enters the up-down combined reactor 10 from the catalyst tube 46 and the catalyst inlet pipe 16, and enters the reactor B10B from the catalyst tube B 46B and the catalyst inlet pipe B16B;

[0088] The first reaction raw material F12 is one or more of recycled cracked light oil and naphtha components. In this embodiment, recycled cracked light oil is used. The second reaction raw material F13 is straight-run diesel. The reaction raw material F15 of reactor B is heavy oil with a hydrogen content of 12.6% to 13.2%.

[0089] The first reaction raw materials F12 and C4 are heated to 400°C for feeding, the second reaction raw material F13 is fed at a temperature of 200°C, and the reactor B reaction raw material F15 is heat exchanged to 300°C; the reaction temperature of the first reaction raw material F12 is 675°C, the reaction temperature of the second reaction raw material F13 is 630°C, and the reaction temperature of the reactor B reaction raw material F15 is 620°C; the steam ratio of the up-and-down combined reactor 10 relative to the total feed amount of the first reaction raw material F12 and the second reaction raw material F13 is 30%, and the steam ratio of the reactor B10B relative to the feed amount of the reactor B reaction raw material F15 is 40%; the rest is the same as in Example 4. Example 7:

[0090] The apparatus shown in FIG6 is used for fluidized catalytic conversion to produce ethylene and propylene. A regenerator 30, a reaction settler 20, and an up-and-down combined reactor 10 are provided. The up-and-down combined reactor comprises an independent up-and-down portion 12 and an up-and-down portion B12B, while the down-and-down portion 13 is shared. The connecting section 15 between the up-and-down portion 12 and the down-and-down portion 13, as well as the connecting section 15B between the up-and-down portion B12B and the down-and-down portion 13, are both connected in a tee.

[0091] The upward section 12 is provided with only one catalyst circulation path from the regenerator 30. The catalyst from the regenerator 30 is first steam stripped in the regeneration agent stripper 40, enters the bottom diameter expansion section 11 of the reactor through the catalyst tube 46 and the catalyst inlet tube 16, and first reacts with C4. The catalyst after the reaction with C4 enters the inner tube 18 from the bottom and reacts with the first reaction feed F12. The reaction product and catalyst flow upward out of the inner tube 18, mix with the C4 reaction product, and enter the upward section 12 to continue the reaction. The second reaction feed F13 enters the reactor at the upper end of the downward section 13 and undergoes catalytic cracking in the downward section 13.

[0092] The reaction feedstock F12B of the upstream portion B enters the reactor B12B from the bottom. The catalyst from the regenerator 30 is first steam stripped in the regeneration agent stripper B40B and enters the lower portion of the upstream portion B12B through the catalyst tube 46B and the catalyst inlet tube 16B. The reaction feedstock F12B of the upstream portion B first undergoes a catalytic cracking reaction in the upstream portion B12B and then enters the descending portion 13, where it is mixed with the reaction products and catalyst from the upstream portion 12 and further catalytic cracking is carried out in the common descending portion 13. The first reaction feedstock F12 is recycled light hydrocarbons with a carbon number of C7 or less, the reaction feedstock F12B of the upstream portion B is naphtha, and the second reaction feedstock F13 is heavy oil. C4 is olefins after butane separation, and the olefin content is greater than 95%. The temperature of the reaction feedstock F12B of the upstream portion B is 420°C.

[0093] The reaction temperature of the upstream section 12 is 644°C, the reaction temperature of the upstream section B12B is 650°C, and the reaction temperature of the downstream section 13 is 610°C. The reaction time of the upstream section 12 is 5 seconds, the reaction time of the upstream section B12B is 5 seconds, and the reaction time of the downstream section is 4 seconds. The catalyst is an alkaline earth oxide containing 10% ZSM-5 molecular sieve. Other parts are the same as those in Example 4. In the specific implementation of the present invention, the upstream section B12B can preferably use a riser, a variable diameter riser, a combination of different fluidization modes, or the same as the upstream reactor 12, as will be appreciated by those skilled in the art.

[0094] Finally, it should be noted that the above description is only used to illustrate the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the present invention can be modified or replaced with equivalents without departing from the spirit and scope of the present invention, which should all be included in the scope of protection of the present invention.

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

Claims

1. A method for preparing ethylene and propylene by fluidized catalytic conversion, characterized in that: One or more reactors are provided, at least one of which is a continuous up-and-down combination reactor, and the reactant flow and the catalyst are continuously passed through the two parts of the up-and-down reaction and the down-and-down reaction; the reaction raw materials of at least one reactor are composed of two parts, one part of the reaction raw materials is subjected to a high temperature catalytic cracking reaction in the up-and-down part of the reactor to achieve the target of high ethylene and propylene yield, and then enters the down-and-down part of the reactor together with the catalyst for reaction, and the other part of the reaction raw materials enters the reactor at the downstream of the up-and-down combination reactor connection part or in the down-and-down reaction part, and reacts under the condition of reduced temperature; the method is carried out according to the following process: (1) The up-and-down combined reactor (10) comprises an up-and-down portion (12) and a down-and-down portion (13), the two portions forming a whole; the up-and-down portion (12) is used for catalytic cracking of a first reaction raw material (F12) at a relatively high temperature to produce ethylene and propylene, and the down-and-down portion (13) chemically stabilizes the catalytic cracking product of the up-and-down portion to achieve delayed removal of coke; the down-and-down portion (13) simultaneously completes catalytic cracking of a second reaction raw material (F13) at a lower temperature than the first reaction raw material (F12) to produce propylene and ethylene; (2) The first reaction raw material (F12) enters the upward and downward combined reactor (10) at the lower part or bottom of the upward part (12), and the catalyst from the regenerator (30) first enters the upward part (12) through the catalyst tube (46) and the catalyst inlet tube (16), contacts with the first reaction raw material (F12) to undergo catalytic cracking reaction while flowing upward, and then the catalytic cracking product and the catalyst enter the downward part (13) together; or, the catalyst from the regenerator (30) enters the upward part (12) in two ways through the catalyst tube (46) and the catalyst inlet tube (16), and the upper catalyst tube C (46C) and the catalyst inlet tube C (26); (3) the second reaction raw material (F13) enters the up-and-down combined reactor (10) at the upper end of the down-flowing section (13), or enters the up-and-down combined reactor (10) at the connecting section (15) between the down-flowing section (13) and the up-flowing section (12), or first enters the up-and-down combined reactor (10) at the upper part of the up-flowing section (12) and then enters the down-flowing section (13); (4) The flow of the first reaction raw material (F12) and the second reaction raw material (F13) after the reaction is separated into gas and solid in the reaction settler (20), and the reaction product (F14) after the catalyst is separated flows out of the reaction settler (20) from the product outlet (28) of the reaction settler; the separated catalyst settles to the stripping section (23) below, and the stripped catalyst enters the regenerator (30) from the spent catalyst pipe (21) and the spent catalyst inlet pipe (36) of the regenerator for regeneration, and after regeneration, enters the upward part (12) of the upward and downward combined reactor (10) for recycling.

2. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1, characterized in that the upward part (12) is provided with two catalyst circulations from the regenerator (30), the catalyst from the regenerator (30) is firstly subjected to steam stripping in the regenerator stripper (40) and the regenerator stripper C, respectively, and then enters the upward and downward combined reactor (10) through the catalyst tube (46) and the catalyst inlet tube (16), and the catalyst tube C (46C) and the catalyst inlet tube C (26), respectively; the second reaction raw material (F13) enters the upward and downward combined reactor (10) above the catalyst inlet tube C (26).

3. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1 or 2, characterized in that the descending part (13) of the up-and-down combined reactor (10) enters the reaction settler (20) from the top of the reaction settler downward, and the outlet is vertically downward, and the catalyst in the reactor flows downwardly out of the outlet of the descending part (13), and the first stage of gas-solid separation is achieved by relying on the momentum formed by the gravity of the catalyst and the downward flow velocity; the gas and part of the catalyst then flow upward in the opposite direction and enter the cyclone separator (22) for further gas-solid separation.

4. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1 or 2, characterized in that the descending part (13) is outside the reaction settler (20), and the outlet at the lower end of the descending part turns to enter the reaction settler (20), and gas-solid separation is carried out in the reaction settler (20).

5. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 3, characterized in that a gas passage tube (24) is arranged on the periphery of the descending portion (13), and the gas and part of the catalyst flowing out from the outlet of the descending portion (13) enter the annular gap (25) between the gas passage tube (24) and the descending portion (13) upward, and then enter the cyclone separator (22), or enter the cyclone separator (22) from the annular gap (25) through the outlet pipe (25B).

6. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 5, characterized in that the elevation of the lower end of the gas passage pipe (24) is higher than the outlet of the descending part (13).

7. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 3, characterized in that a cyclone separator (14) is arranged outside the outlet of the descending part (13), and a gas channel pipe (24) is arranged outside the cyclone separator (14); the catalyst separated by the cyclone separator settles by gravity to the stripping section (23) below, and the gas and part of the catalyst flow upward in the annular gap (25) between the gas channel pipe (24) and the descending part (13) and enter the cyclone separator (22), or enter the cyclone separator (22) from the annular gap (25) through the outlet pipe (25B).

8. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1, characterized in that an ascending section (12), an ascending section B (12B) and a common descending section (13) are provided; the first reaction raw material (F12) is first subjected to catalytic cracking in the ascending section (12), and then turns to enter the descending section (13) together with the catalyst for further catalytic cracking; the reaction raw material (F12B) of the ascending section B is first subjected to catalytic cracking reaction in the ascending section B (12B), and then enters the descending section (13), is mixed with the reaction product and catalyst from the ascending section (12), and further subjected to catalytic cracking in the common descending section (13); the second reaction raw material (F13) enters the reactor for reaction in the descending section (13), or enters the reactor at the connecting section of the descending section (13) with the ascending section (12) and / or the ascending section B (12B), or enters the reactor at the downstream or upper part of the ascending section (12) or / and the ascending section B (12B).

9. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 8, characterized in that part of the catalyst is separated from the upper part of the upstream part (12) and / or the upstream part B (12B), and the remaining part of the catalyst continues the downstream reaction.

10. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1, characterized in that part of the catalyst is separated from the upper part of the upward part (12), and the remaining part of the catalyst continues to react downstream.

11. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1, characterized in that at least one reactor is designed in a folded form, using an up-and-down combination form, the folded reactor comprises at least two vertical reaction sections and a transverse connecting section, wherein the length of the up-and-down vertical reaction section is greater than that of the down-and-down vertical reaction section, the vertical reaction section and the transverse connecting section are connected in a bend connection or a tee form, the reactor outlet is connected downward or transversely to a gas-solid separator, and the catalyst enters the reactor in the up-and-down vertical reaction section.

12. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1, characterized in that the reaction temperature of the upstream part of the up-and-down combined reactor is higher than the reaction temperature of the downstream part, the reaction temperature of the first reaction raw material (F12) in the upstream part (12) is 600°C-720°C, and the reaction time is 1.0 second-10.0 seconds; the reaction temperature of the downstream part (13) is 570°C-670°C, and the reaction time is 1.0 second-7.0 seconds; the reaction pressure is 80kPa-200kPa (gauge).

13. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1, characterized in that the first reaction raw material (F12) and / or the second reaction raw material (F13) are petroleum hydrocarbon raw materials, or methanol, or liquefied waste plastics, or two or more of the above raw materials reacted together.

14. The method for preparing ethylene and propylene by fluidized catalytic conversion as claimed in claim 1, characterized in that the first reaction raw material (F12) is a raw material with an actual boiling point lower than 200°C; and the second reaction raw material (F13) is a raw material with an actual boiling point higher than 300°C in a mass ratio of more than 90%.

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