Process for the production of low carbon olefins from oxygenates

Abstract

A process for producing lower olefins from oxygenates, comprising the step of contacting a feedstock comprising oxygenates with a molecular sieve catalyst in a fluid bed reaction zone under effective conditions to produce an ethylene and / or propylene containing product; said effective conditions including controlling the ratio of the mass of catalyst having various amounts of coke to the total mass of catalyst in said fluid bed reaction zone as follows: the mass of catalyst having less than 3 wt% of coke to the total mass of catalyst in said fluid bed reaction zone.

Description

Technical Field

[0001] This invention relates to a method for producing low-carbon olefins from oxygen-containing compounds. Background Technology

[0002] Low-carbon olefins, primarily ethylene and propylene, are two important basic chemical raw materials, and their demand is constantly increasing. Generally, ethylene and propylene are produced via the petroleum route, but due to the limited supply and high price of petroleum resources, the cost of producing ethylene and propylene from petroleum resources is continuously increasing. In recent years, efforts have been made to develop technologies for converting raw materials into ethylene and propylene. One important class of alternative raw materials for low-carbon olefin production are oxygen-containing compounds, such as alcohols (methanol, ethanol), ethers (dimethyl ether, methyl ethyl ether), and esters (dimethyl carbonate, methyl formate). These oxygen-containing compounds can be converted from energy sources such as coal, natural gas, and biomass. Some oxygen-containing compounds can already be produced on a large scale; for example, methanol can be produced from coal or natural gas using mature processes, achieving production scales of millions of tons. Due to the wide availability of oxygen-containing compounds and the economic viability of converting them into low-carbon olefins, processes for converting oxygen-containing compounds into olefins (OTO), especially methanol-to-olefins (MTO), are receiving increasing attention.

[0003] Reference US4499327 provides a detailed study on the application of silica-alumina molecular sieve catalysts in the methanol-to-olefins (MTO) process, concluding that SAPO-34 is the preferred catalyst for the MTO process. SAPO-34 catalyst exhibits high selectivity for low-carbon olefins and also high activity, enabling the methanol-to-olefins reaction time to be less than 10 seconds, and even within the reaction time range of risers.

[0004] Document US6166282 discloses a technology and reactor for the conversion of methanol to low-carbon olefins. It employs a fast fluidized bed reactor. After the gas phase reacts in the dense-phase reaction zone with a low gas velocity, it rises to a rapidly decreasing-diameter zone, where a special gas-solid separation device initially separates most of the entrained catalyst. Because the product gas and catalyst are rapidly separated after the reaction, secondary reactions are effectively prevented. Simulation calculations show that compared to traditional bubbling fluidized bed reactors, this fast fluidized bed reactor significantly reduces the inner diameter and the required catalyst storage. The carbon-based yield of low-carbon olefins in this method is generally around 77%.

[0005] Document CN101328103A discloses a method for converting methanol or dimethyl ether into low-carbon olefins. The method involves feeding methanol or dimethyl ether into the reaction zone of a fluidized bed reactor, where it contacts a catalyst comprising a silica-aluminophosphate molecular sieve. Under the conditions of a reaction pressure of 0.05–1 MPa (gauge pressure), an average reaction zone temperature of 450–550 °C, and an average empty gas velocity of 0.8–2.0 m / s, the average density of the reaction zone is 20–300 kg / m³, and the average coking amount of the catalyst in the reaction zone is 1.5–4.5% by weight. The carbon-based selectivity for low-carbon olefins reaches a maximum of 81.51% by weight.

[0006] However, with the increasing market demand for ethylene and propylene, higher requirements are being placed on low-carbon olefin production technology. Summary of the Invention

[0007] The inventors of this invention have discovered that in the process of converting oxygen-containing compounds (especially methanol) into low-carbon olefins in the prior art, a certain amount of carbon deposits on the catalyst are necessary to ensure high selectivity for low-carbon olefins. In a fluidized bed reactor, there is a catalyst cycle between reaction and regeneration, which inevitably leads to the mixing of multiple catalyst streams in the reaction zone. The amount of carbon deposits on the catalyst in the reaction zone is an average concept, and the mixing quality of catalysts with low and high carbon deposits is crucial for improving the selectivity for low-carbon olefins.

[0008] Building upon this, the inventors further discovered that the reactivity of the feedstock varies significantly with catalysts of different coking amounts, especially when reacting with catalysts with a coking amount of less than 3 wt%, where the selectivity for low-carbon olefins decreases drastically. However, to ensure a high feedstock conversion rate, catalysts with a coking amount of less than 3 wt% are essential. Controlling the content and distribution of this lower coking amount catalyst, while simultaneously controlling the catalyst concentration within the reaction zone, is an effective way to resolve this contradiction, ensuring both a high methanol conversion rate and high low-carbon olefin selectivity. Furthermore, the inventors unexpectedly discovered that controlling the difference in coking amount among the mixed catalysts within the reaction zone is crucial for achieving the desired technical effect.

[0009] This invention is based on these findings.

[0010] Specifically, the present invention provides, for example, the following embodiments:

[0011] 1. A method for producing low-carbon olefins from oxygen-containing compounds, comprising the step of contacting a feedstock containing oxygen-containing compounds with a molecular sieve catalyst in a fluidized bed reaction zone to generate ethylene and / or propylene products under effective conditions.

[0012] The effective conditions include, within the fluidized bed reaction zone, controlling the proportion of catalyst mass with various coking amounts to the total catalyst mass within the fluidized bed reaction zone, based on the mass of molecular sieves in the catalyst, as follows:

[0013] The proportion of catalyst with a coke content of less than 3% by weight to the total catalyst mass in the fluidized bed reaction zone is 1 to 20% by weight, preferably 1 to 15% by weight, 1.5 to 10% by weight, or 2 to 5% by weight;

[0014] The catalyst with a coke content of 3 to less than 5% by weight accounts for 10 to 70% by weight, preferably 15 to 60% by weight, 20 to 50% by weight, or 30 to 45% by weight;

[0015] The catalyst, with a coking content of 5-10% by weight, comprises 10-88% by weight, preferably 15-80% by weight, 20-70% by weight, or 30-60% by weight.

[0016] 2. According to the method described in Embodiment 1, the ratio of the gas phase volume to the total catalyst volume in the fluidized bed reaction zone is 1 to 15, preferably 5 to 12.

[0017] 3. According to the method of embodiment 1 or 2, the raw material enters the reaction zone of the fluidized bed reactor via a distribution device, wherein the maximum difference in the amount of carbon deposited on the catalyst particles within a range of 1 / 2 bed height from the distribution device is less than 8% by weight, preferably less than 5% by weight, or less than 3% by weight.

[0018] 4. According to the method of embodiment 3, the maximum difference in the amount of carbon deposited on the catalyst particles within a range of 1 / 2 bed height from the distribution device is greater than 0.1% by weight.

[0019] 5. A method for producing low-carbon olefins from oxygen-containing compounds, comprising the step of contacting an oxygen-containing compound feedstock with a molecular sieve catalyst in a fluidized bed reaction zone to generate ethylene and / or propylene products under effective conditions.

[0020] The raw material enters the reaction zone of the fluidized bed reactor via a distribution device, wherein the maximum difference in carbon deposition on the catalyst particles within a 1 / 2 bed height range from the distribution device is less than 8% by weight, preferably less than 5% by weight, or less than 3% by weight.

[0021] 6. According to the method of embodiment 5, the maximum difference in the amount of carbon deposited on the catalyst particles within a range of 1 / 2 bed height from the distribution device is greater than 0.1% by weight.

[0022] 7. According to the method of embodiment 5 or 6, the effective conditions include, within the fluidized bed reaction zone, controlling the proportion of catalyst mass with various coking amounts to the total catalyst mass within the fluidized bed reaction zone, based on the mass of molecular sieves in the catalyst, as follows:

[0023] The proportion of catalyst with a coke content of less than 3% by weight to the total catalyst mass in the fluidized bed reaction zone is 1 to 20% by weight, preferably 1 to 15% by weight, 1.5 to 10% by weight, or 2 to 5% by weight;

[0024] The catalyst with a coke content of 3 to less than 5% by weight accounts for 10 to 70% by weight, preferably 15 to 60% by weight, 20 to 50% by weight, or 30 to 45% by weight;

[0025] The catalyst, with a coking content of 5-10% by weight, comprises 10-88% by weight, preferably 15-80% by weight, 20-70% by weight, or 30-60% by weight.

[0026] 8. According to the method described in Embodiment 7, the ratio of the gas phase volume to the total catalyst volume in the fluidized bed reaction zone is 1 to 15, preferably 5 to 12.

[0027] 9. The method according to any of the foregoing embodiments, wherein the oxygen-containing compound raw material includes methanol.

[0028] 10. The method according to any of the foregoing embodiments, wherein the molecular sieve is a silica-alumino-phosphorus molecular sieve, preferably SAPO-18, SAPO-34, SAPO-5 or a combination thereof.

[0029] 11. The method according to any of the foregoing embodiments, wherein the fluidized bed reaction zone is a dense phase, turbulent or rapid fluidization type, preferably a rapid fluidization type.

[0030] 12. The method according to any of the foregoing embodiments, wherein the effective conditions further include: reaction temperature of 400-550°C and reaction pressure of 0-1 MPaG.

[0031] 13. According to any of the methods described in the foregoing embodiments, the difference in the amount of coke deposited between the unused catalyst and the regenerated catalyst is no more than 7% by weight, preferably no more than 6% by weight, and more preferably no more than 5% by weight.

[0032] 14. According to any of the methods described in the foregoing embodiments, the catalyst with a coke content of less than 3% by weight is uniformly distributed in the fluidized bed reaction zone.

[0033] 15. According to any of the methods described in the foregoing embodiments, the gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone.

[0034] Preferably, according to an exemplary embodiment of the present invention, a regeneration pipeline outlet is provided at the lower part of the reaction zone, and a catalyst distributor is provided at the regeneration pipeline outlet, the catalyst distributor being arranged substantially horizontally along the radial direction of the reaction zone.

[0035] 16. According to any one of embodiments 3-15, the catalyst in the reaction zone is deactivated to form a spent catalyst, which is then regenerated in a regenerator through a spent catalyst pipeline to form a regenerated catalyst, which is then returned to the fluidized bed reaction zone through a regeneration pipeline; wherein the ratio of the regenerated catalyst to the spent catalyst in the reaction zone is controlled to be 0.01 to 1, preferably 0.05 to 0.5, more preferably 0.07 to 0.3; and the amount of coke deposited on the regenerated catalyst is 0 to 5% by weight, preferably 0.05 to 3% by weight, more preferably 0.5 to 2% by weight.

[0036] 17. A fluidized bed reactor for implementing the method for producing low-carbon olefins from oxygen-containing compounds as described in any of the foregoing embodiments, comprising:

[0037] The reaction zone is used to receive methanol feedstock, bring it into contact with the catalyst, and generate olefin products, wherein the process deactivates the catalyst at least partially, resulting in a spent catalyst.

[0038] Gas-solid rapid separation equipment is used to separate the catalyst to be produced from the reaction zone;

[0039] Cyclone separators are used to receive gaseous products separated by rapid gas-solid separation equipment, as well as some unseparated catalysts, for further separation.

[0040] The stripping zone is used to receive spent catalyst from the feed legs of the cyclone separator; and

[0041] The catalyst external circulation inclined tube is used to return at least a portion of the stripped catalyst from the stripping zone to the bottom of the reaction zone. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the fluidized bed reactor described in the method of the present invention.

[0043] Figure 1 middle,

[0044] 1 is the reactor feed line;

[0045] 2 is the reactor reaction zone;

[0046] 3 is the gas-solid rapid separation zone;

[0047] 4 is the stripping area;

[0048] 5 represents the inclined tube for external circulation of the reactor;

[0049] 6 represents raw material distribution equipment;

[0050] 8 represents the reactor gas-solid cyclone separator;

[0051] 9 is the reactor separation zone;

[0052] 11 is the product gas outlet pipeline;

[0053] 14 is the inclined tube to be generated;

[0054] 15 is a regeneration inclined tube;

[0055] Technical effect

[0056] According to the method of the present invention, both a high raw material conversion rate and a high low-carbon olefin selectivity can be guaranteed, with the low-carbon olefin selectivity reaching more than 84%. Detailed Implementation

[0057] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0058] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0059] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0060] In the context of this specification, the terms “basically,” “about,” or similar expressions mean that deviations that are acceptable or reasonable to a person skilled in the art are permitted, such as deviations within ±10%, ±5%, ±1%, ±0.5%, or ±0.1%.

[0061] In the context of this specification, the term "reaction zone" is used in relation to a fluidized bed reactor. Ideally, a fluidized bed reactor comprises a reaction zone, an inlet zone, and a separation zone. The "inlet zone" is the section in the reactor where the feed and catalyst are introduced. The "reaction zone" is the section in the reactor where the feed and catalyst come into contact under conditions that effectively convert the oxygen-containing compounds of the feed into light olefin products. The "separation zone" is the section in the reactor where the catalyst and any other solids within the reactor are separated from the products. Typically, the reaction zone is located between the inlet zone and the separation zone.

[0062] In the context of this specification, "gas phase" includes one or more of the following: heated and vaporized raw material methanol, dilution gas (such as water vapor), and gas phase reaction products (such as light olefins, C4 hydrocarbons, etc.).

[0063] In the context of this specification, it should be noted that the volume of the reaction zone, in addition to the volume occupied by the gas phase, is the volume of the catalyst. The ratio of the gas phase volume to the catalyst volume indicates the volume fraction of solid catalyst particles in the gas-solid mixture within the reaction zone.

[0064] In the context of this specification, the amount of catalyst coking (or average amount of coking) is calculated by dividing the mass of coking on the catalyst by the mass of the catalyst itself. The method for determining the mass of coking on the catalyst is as follows: 0.1 to 1 gram of carbonized catalyst is weighed and burned in a high-temperature carbon analyzer. The mass of carbon dioxide produced during combustion is measured by infrared spectroscopy, thus obtaining the mass of coking on the catalyst. To determine the amount of catalyst coking within the reaction zone, equal amounts of small portions of catalyst can be continuously or periodically extracted or directly taken from various locations within the reaction zone.

[0065] In the context of this specification, after the catalyst in the fluidized bed reaction zone is deactivated, a dormant catalyst (dormant agent) is formed. The dormant catalyst enters a regenerator for regeneration to form a regenerated catalyst (regenerated agent), which is then returned to the fluidized bed reaction zone.

[0066] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight, and the pressure is gauge pressure.

[0067] In the context of this specification, any two or more embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0068] According to one embodiment of the present invention, a method for producing low-carbon olefins from oxygen-containing compounds is provided. The method includes the step of contacting an oxygen-containing compound feedstock with a molecular sieve catalyst in a fluidized bed reaction zone to generate ethylene- and propylene-containing products under effective conditions.

[0069] According to one embodiment of the present invention, the oxygen-containing compound raw material comprises an aliphatic alcohol containing 1-20 carbon atoms, preferably 1-10 carbon atoms, and more preferably 1-4 carbon atoms. Examples include methanol, ethanol, n-propanol, isopropanol, methyl ethyl ether, dimethyl ether, diethyl ether, diisopropyl ether, formaldehyde, dimethyl carbonate, dimethyl ketone, acetic acid, and mixtures thereof; preferably methanol, ethanol, dimethyl ether, diethyl ether, and mixtures thereof; more preferably methanol and dimethyl ether; and most preferably methanol.

[0070] According to one embodiment of the present invention, the effective conditions include: within the fluidized bed reaction zone, the mass of catalyst with a coke content of less than 3% by weight, based on the mass of molecular sieves in the catalyst, accounts for 1 to 20% by weight of the total mass of catalyst in the fluidized bed reaction zone, preferably 1 to 15% by weight, more preferably 1.5 to 10% by weight, and even more preferably 2 to 5% by weight. The proportion of catalyst with a coke content of less than 3% by weight in the total mass of catalyst in the fluidized bed reaction zone is controlled by adjusting the regenerator circulation rate and the coke content of the regenerator (i.e., the degree of carbonization in the regenerator).

[0071] According to one embodiment of the present invention, the catalyst with a coke content of less than 3% by weight is uniformly distributed in the fluidized bed reaction zone.

[0072] According to one embodiment of the present invention, the effective conditions further include: in the fluidized bed reaction zone, the ratio of gas phase volume to total catalyst volume is 1 to 15, preferably 5 to 12.

[0073] According to one embodiment of the present invention, the effective conditions further include: a reaction temperature of 400–550°C and a reaction pressure of 0–1 MPa.

[0074] According to one embodiment of the present invention, the molecular sieve is a silica-alumino-phosphorus molecular sieve, preferably SAPO-18, SAPO-34, SAPO-5, or a combination thereof, more preferably SAPO-34. Methods for preparing SAPO molecular sieves or SAPO molecular sieve catalysts are well known in the art.

[0075] According to one embodiment of the present invention, the fluidized bed reaction zone is a dense phase, turbulent or rapid fluidization type, preferably a rapid fluidization type.

[0076] According to one embodiment of the present invention, the difference in coke deposits between the spent catalyst and the regenerated catalyst is no more than 7% by weight, preferably no more than 6% by weight, and more preferably no more than 5% by weight. The amount of coke deposits on the spent catalyst can be directly controlled by the reaction, while the amount of coke deposits on the regenerated catalyst can be controlled by the degree of regeneration in the regenerator.

[0077] According to one embodiment of the present invention, the gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone. The separation device is preferably a cyclone separator.

[0078] An exemplary embodiment 1 of the present invention is as follows: Figure 1 As shown. See also Figure 1 The fluidized bed reactor used in this invention is a rapid fluidized bed, dense-phase fluidized bed, or turbulent fluidized bed. A methanol feedstock enters the reactor via feed line 1 and then passes through feed distribution equipment 6 into reaction zone 2, where it contacts the molecular sieve catalyst. The reaction produces a product containing low-carbon olefins, causing at least partial deactivation of the catalyst, forming a spent catalyst. The spent catalyst then passes through a gas-solid rapid separation zone 3 into reactor separation zone 9. Most of the catalyst separated by the gas-solid rapid separation equipment 3 enters stripping zone 4, while the gaseous product and some spent catalyst not separated by the gas-solid rapid separation equipment are further separated by a cyclone separator 8. The spent catalyst separated by the cyclone separator 8 is returned to stripping zone 4 via the cyclone separator's feed leg, while the separated gaseous product enters subsequent separation stages via outlet line 11. The catalysts separated by the gas-solid rapid separation zone 3 and the cyclone separator 8 are combined and stripped in the stripping zone 4. They are then divided into two parts. One part is returned to the bottom of the reaction zone 2 through the catalyst external circulation inclined tube 5. The other part is sent to the regenerator for carbon burning and regeneration through the catalyst waiting inclined tube 14. The regenerated catalyst is then returned to the reaction zone 2 through the regeneration inclined tube 15.

[0079] Example

[0080] The present invention will be further described in detail below through embodiments and comparative examples, but the present invention is not limited to the following embodiments.

[0081] Example I-1

[0082] A fast fluidized bed reactor is used. Methanol feedstock (95 wt% purity) enters the fast fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst, which is then regenerated in a regenerator to form a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. The difference in coke deposition between the spent catalyst and the regenerated catalyst is 5 wt%. The gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone. The effective conditions are: reaction temperature 450℃, reaction gauge pressure 0.15 MPa, catalyst mass with less than 3 wt% coke deposition in the reaction zone (based on the molecular sieve mass) is 14 wt%, catalyst with 3 to less than 5 wt% coke deposition is 68 wt%, catalyst with 5-10 wt% coke deposition is 16 wt%, and the gas phase volume to catalyst volume ratio is 10. Sampling analysis results showed that the methanol conversion rate was 99.96% and the ethylene + propylene carbon-based selectivity was 84.52%.

[0083]

Example I-2

[0084] A dense-phase fluidized bed reactor is used. Methanol feedstock (95% purity) enters the dense-phase fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst, which is then regenerated in a regenerator to form a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. The difference in coke deposition between the spent catalyst and the regenerated catalyst is 6 wt%. The gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone. The effective conditions are: reaction temperature 550℃, reaction gauge pressure 1 MPa, catalyst mass with less than 3 wt% coke deposition in the reaction zone (based on the molecular sieve mass) is 18 wt%, catalyst with 3 to less than 5 wt% coke deposition accounts for 63 wt%, catalyst with 5-10 wt% coke deposition accounts for 17 wt%, and the gas phase volume to catalyst volume ratio is 1. Sampling analysis results showed that the methanol conversion rate was 99.32% and the ethylene + propylene carbon-based selectivity was 82.14%.

[0085]

Example I-3

[0086] A turbulent fluidized bed is used. Methanol feedstock (95% purity) enters the turbulent fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst, which is then regenerated in a regenerator to form a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. The difference in coke deposition between the spent catalyst and the regenerated catalyst is 3 wt%. The gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone. The effective conditions are: reaction temperature 400℃, reaction gauge pressure 0.05 MPa, catalyst mass with less than 3 wt% coke deposition in the reaction zone (based on the molecular sieve mass) is 15 wt%, catalyst with 3 to less than 5 wt% coke deposition is 66 wt%, catalyst with 5-10 wt% coke deposition is 16 wt%, and the gas phase volume to catalyst volume ratio is 3. Sampling analysis results showed that the methanol conversion rate was 99.09% and the ethylene + propylene carbon-based selectivity was 83.99%.

[0087]

Example I-4

[0088] A fast fluidized bed reactor is used. Methanol feedstock (99% purity) enters the fast fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst, which is then regenerated in a regenerator to form a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. The difference in coke deposition between the spent catalyst and the regenerated catalyst is 5 wt%. The gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone. The effective conditions are: reaction temperature 480℃, reaction gauge pressure 0.2 MPa, catalyst mass with less than 3 wt% coke deposition in the reaction zone (based on the molecular sieve mass) is 5 wt%, catalyst with 3 to less than 5 wt% coke deposition is 50 wt%, catalyst with 5-10 wt% coke deposition is 42 wt%, and the gas phase volume to catalyst volume ratio is 6. Sampling analysis results showed that the methanol conversion rate was 99.90% and the ethylene + propylene carbon-based selectivity was 84.22%.

[0089]

Example I-5

[0090] Methanol feedstock (99% purity) enters the rapid fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst, which is then regenerated in a regenerator to form a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. The difference in coke deposition between the spent catalyst and the regenerated catalyst is 6 wt%. The gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone. The effective conditions are: reaction temperature 480℃, reaction gauge pressure 0.15 MPa, catalyst mass with less than 3 wt% coke deposition in the reaction zone is 10 wt% (based on the mass of the molecular sieve on the catalyst), catalyst with 3 to less than 5 wt% coke deposition is 45 wt%, catalyst with 5-10 wt% coke deposition is 40 wt%, and the gas phase volume to catalyst volume ratio is 12. Sampling analysis results showed that the methanol conversion rate was 99.96% and the ethylene + propylene carbon-based selectivity was 84.78%.

[0091] Comparative Example I-1

[0092] Following the conditions and procedures described in [Examples I-5], except that the catalyst mass with a coke content of less than 3 wt% in the reaction zone was 30 wt%, and the gas phase volume to catalyst volume ratio was 0.5. Sampling analysis results showed that the methanol conversion rate was 99.99%, and the ethylene + propylene carbon-based selectivity was 80.32%.

[0093] Comparative Example I-2

[0094] Following the conditions and procedures described in [Examples I-5], except that the catalyst mass with a coke content of less than 3 wt% in the reaction zone was 30 wt%, and the gas phase volume to catalyst volume ratio was 20. Sampling analysis results showed that the methanol conversion rate was 99.67%, and the ethylene + propylene carbon-based selectivity was 79.61%.

[0095] Comparative Example I-3

[0096] Following the conditions and procedures described in [Examples I-5], except that the catalyst mass with a coke content of less than 3 wt% in the reaction zone was 10 wt%, and the gas phase volume to catalyst volume ratio was 20. Sampling analysis results showed that the methanol conversion rate was 99.07%, and the ethylene + propylene carbon-based selectivity was 83.98%.

[0097] Comparative Example I-4

[0098] Following the conditions and procedures described in [Examples I-5], except that the catalyst mass with a coke content of less than 3 wt% in the reaction zone was 0.5 wt%, and the gas phase volume to catalyst volume ratio was 12. Sampling analysis results showed that the methanol conversion rate was 99.01%, and the ethylene + propylene carbon-based selectivity was 83.76%.

[0099] Comparative Example I-5

[0100] Following the conditions and procedures described in [Examples I-5], except that the difference in coke deposition between the catalyst under development and the regenerated catalyst was 9 wt%. Sampling analysis results showed a methanol conversion rate of 98.97% and an ethylene + propylene carbon-based selectivity of 83.55%.

[0101] Obviously, the method of the present invention can achieve the goal of increasing the yield of low-carbon olefins and can be used in the industrial production of low-carbon olefins.

[0102]

Example II-1

[0103] A fast fluidized bed reactor is used. Methanol feedstock (95 wt% purity) enters the fast fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst, which is then regenerated in a regenerator to form a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. A catalyst distributor is installed at the outlet of the regeneration pipeline. The distributor is arranged horizontally along the radial direction of the fluidized bed reactor, uniformly distributing the regenerated catalyst on the radial plane of the reaction zone. The catalyst distributor is equipped with a conveying medium, which is water vapor. The fluidized bed reactor reaction zone is a fluidized bed. The fluidized bed is divided into a dense phase and a dilute phase. The region from the distribution device to half the bed height is located in the dense phase section (for fast fluidized bed types, the height of the dense phase section is the same as the reaction zone height). The maximum difference in carbon deposition on catalyst particles within this range is 3.3%. The effective reaction conditions are: reaction temperature 480℃, reaction gauge pressure 0.15MPa. The ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled at 0.1, the carbon deposition of the regenerated catalyst is 1.0% by weight, and the methanol conversion rate from the distribution device to half the bed height is 85%. Sampling analysis results show that the methanol conversion rate at the reactor outlet is 99.95%, and the ethylene + propylene carbon-based selectivity is 84.36%.

[0104]

Example II-2

[0105] Following the conditions and steps described in Example II-1, methanol feedstock (95 wt% methanol purity) enters the rapid fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst. This spent catalyst enters a regenerator for regeneration, forming a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. A catalyst distributor is installed at the outlet of the regeneration pipeline. The distributor is arranged horizontally along the radial direction of the fluidized bed reactor, uniformly distributing the regenerated catalyst on the radial plane of the fluidized bed reactor reaction zone. The catalyst distributor is equipped with a conveying medium. The transport medium is steam; the fluidized bed in the reaction zone of the fluidized bed reactor is divided into dense and dilute phase sections, with the area from the distribution device to half the bed height located in the dense phase section; the maximum difference in carbon deposition on catalyst particles within this range is 2.5%; the effective reaction conditions are: reaction temperature 480℃, reaction gauge pressure 0.01MPa; the ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled at 0.3; the carbon deposition on the regenerated catalyst is 2% by weight; the methanol conversion rate from the distribution device to half the bed height is 82%. Sampling analysis results show that the methanol conversion rate at the reactor outlet is 99.61%, and the ethylene + propylene carbon-based selectivity is 86.55%.

[0106]

Example II-3

[0107] Following the conditions and steps described in Example II-1, methanol feedstock (95 wt% methanol purity) enters the rapid fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst. This spent catalyst enters a regenerator for regeneration, forming a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. A catalyst distributor is installed at the outlet of the regeneration pipeline. The distributor is arranged horizontally along the radial direction of the fluidized bed reactor, uniformly distributing the regenerated catalyst on the radial plane of the fluidized bed reactor reaction zone. The catalyst distributor is equipped with a conveying medium. The transport medium is steam; the fluidized bed in the reaction zone of the fluidized bed reactor is divided into dense and dilute phase sections, with the area from the distribution device to half the bed height located in the dense phase section; the maximum difference in carbon deposition on catalyst particles within this range is 7%; the effective reaction conditions are: reaction temperature 550℃, reaction gauge pressure 1.0 MPa; the ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled at 0.05; the carbon deposition on the regenerated catalyst is 0.01% by weight; the methanol conversion rate from the distribution device to half the bed height is 91%. Sampling analysis results show that the methanol conversion rate at the reactor outlet is 99.99%, and the ethylene + propylene carbon-based selectivity is 83.59%.

[0108]

Example II-4

[0109] Following the conditions and steps described in Example II-1, methanol feedstock (95 wt% methanol purity) enters the rapid fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst. This spent catalyst enters a regenerator for regeneration, forming a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. A catalyst distributor is installed at the outlet of the regeneration pipeline. The distributor is arranged horizontally along the radial direction of the fluidized bed reactor, uniformly distributing the regenerated catalyst on the radial plane of the fluidized bed reactor reaction zone. The catalyst distributor is equipped with a conveying medium to transport... The feed medium is steam; the fluidized bed in the reaction zone of the fluidized bed reactor is divided into dense and dilute phase sections, with the area from the distribution device to half the bed height located in the dense phase section; the maximum difference in carbon deposition on catalyst particles within this range is 4.5%; the effective reaction conditions are: reaction temperature 490℃, reaction gauge pressure 0.17MPa; the ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled at 0.08; the carbon deposition on the regenerated catalyst is 0.5% by weight; the methanol conversion rate from the distribution device to half the bed height is 88%. Sampling analysis results show that the methanol conversion rate at the reactor outlet is 99.98%, and the ethylene + propylene carbon-based selectivity is 85.19%.

[0110]

Example II-5

[0111] Following the conditions and steps described in Example II-1, methanol feedstock (95 wt% methanol purity) enters the rapid fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst. This spent catalyst enters a regenerator for regeneration, forming a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. A catalyst distributor is installed at the outlet of the regeneration pipeline. The distributor is arranged horizontally along the radial direction of the fluidized bed reactor, uniformly distributing the regenerated catalyst on the radial plane of the fluidized bed reactor reaction zone. The catalyst distributor is equipped with a conveying medium. The transport medium is water vapor; the fluidized bed in the reaction zone of the fluidized bed reactor is divided into dense phase and dilute phase sections, with the area from the distribution device to half the bed height located in the dense phase section; the maximum difference in carbon deposition on catalyst particles within this range is 1.5%; the effective reaction conditions are: reaction temperature 490℃, reaction gauge pressure 0.15MPa; the ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled at 0.5; the carbon deposition on the regenerated catalyst is 5% by weight; the methanol conversion rate from the distribution device to half the bed height is 86%. Sampling analysis results show that the methanol conversion rate at the reactor outlet is 99.92%, and the ethylene + propylene carbon-based selectivity is 85.99%.

[0112]

Example II-6

[0113] Following the conditions and steps described in Example II-1, methanol feedstock (95 wt% methanol purity) enters the rapid fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst. This spent catalyst enters a regenerator for regeneration, forming a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. A catalyst distributor is installed at the outlet of the regeneration pipeline. The distributor is arranged horizontally along the radial direction of the fluidized bed reactor, uniformly distributing the regenerated catalyst on the radial plane of the fluidized bed reactor reaction zone. The catalyst distributor is equipped with a conveying medium. The transport medium is steam; the fluidized bed in the reaction zone of the fluidized bed reactor is divided into dense and dilute phase sections, with the area from the distribution device to half the bed height located in the dense phase section; the maximum difference in carbon deposition on catalyst particles within this range is 3%; the effective reaction conditions are: reaction temperature 400℃, reaction gauge pressure 0.01MPa; the ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled at 0.05; the carbon deposition on the regenerated catalyst is 0.5% by weight; the methanol conversion rate from the distribution device to half the bed height is 81%. Sampling analysis results show that the methanol conversion rate at the reactor outlet is 99.51%, and the ethylene + propylene carbon-based selectivity is 84.80%.

[0114]

Example II-7

[0115] Following the conditions and steps described in Example II-1, methanol feedstock (95 wt% methanol purity) enters the rapid fluidized bed reaction zone and contacts the SAPO-34 molecular sieve catalyst. Under effective conditions, products including ethylene and propylene are generated. After deactivation, the catalyst in the fluidized bed reaction zone forms a spent catalyst. This spent catalyst enters a regenerator for regeneration, forming a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone. A catalyst distributor is installed at the outlet of the regeneration pipeline. The distributor is arranged horizontally along the radial direction of the fluidized bed reactor, uniformly distributing the regenerated catalyst on the radial plane of the fluidized bed reactor reaction zone. The catalyst distributor is equipped with a conveying medium. The transport medium is steam; the fluidized bed in the reaction zone of the fluidized bed reactor is divided into dense and dilute phase sections, with the area from the distribution device to half the bed height located in the dense phase section; the maximum difference in carbon deposition on catalyst particles within this range is 8%; the effective reaction conditions are: reaction temperature 550℃, reaction gauge pressure 0.75MPa; the ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled at 0.15; the carbon deposition on the regenerated catalyst is 0.1% by weight; the methanol conversion rate from the distribution device to half the bed height is 93%. Sampling analysis results show that the methanol conversion rate at the reactor outlet is 99.99%, and the ethylene + propylene carbon-based selectivity is 84.33%.

[0116] Comparative Example II-1

[0117] Following the conditions and procedures described in Example II-1, the maximum difference in carbon deposition on catalyst particles within a range of 1 / 2 bed height from the distribution device was 10%; the methanol conversion rate at the range of 1 / 2 bed height from the distribution device was 71%. Sampling analysis results showed that the methanol conversion rate at the reactor outlet was 99.01%, and the ethylene + propylene carbon-based selectivity was 81.78%.

[0118] Obviously, the method of the present invention can achieve the goal of increasing the yield of low-carbon olefins and can be used in the industrial production of low-carbon olefins.

Claims

1. A method for producing low-carbon olefins from oxygen-containing compounds, comprising the step of contacting a feedstock containing oxygen-containing compounds with a molecular sieve catalyst in a fluidized bed reaction zone to generate ethylene and / or propylene products under effective conditions; The effective conditions include, within the fluidized bed reaction zone, controlling the proportion of catalyst mass with various coking amounts to the total catalyst mass within the fluidized bed reaction zone, based on the mass of molecular sieves in the catalyst, as follows: The mass of catalyst with a coke content of less than 3% by weight accounts for 1 to 20% of the total mass of catalyst in the fluidized bed reaction zone. The catalyst with a coke content of 3 to less than 5% by weight accounts for 10 to 70% by weight; The catalyst with a coking content of 5-10% by weight accounts for 10-88% by weight.

2. The method according to claim 1, characterized in that, The mass of catalyst with a coke content of less than 3% by weight accounts for 2 to 5% of the total mass of catalyst in the fluidized bed reaction zone. The catalyst with a coke content of 3 to less than 5% by weight accounts for 30 to 45% by weight; The catalyst with a coking content of 5-10% by weight accounts for 30-60% by weight.

3. The method according to claim 1 or 2, characterized in that, Within the fluidized bed reaction zone, the ratio of the gas phase volume to the total catalyst volume within the fluidized bed reaction zone is 1 to 15.

4. The method according to claim 3, characterized in that, The ratio of the gas phase volume to the total catalyst volume in the fluidized bed reaction zone is 5 to 12.

5. The method according to claim 1 or 2, wherein the raw material enters the reaction zone of the fluidized bed reactor via a distribution device, characterized in that, The maximum difference in carbon deposition on catalyst particles within a range of 1 / 2 bed height from the distribution device is less than 8% by weight.

6. The method according to claim 5, characterized in that, The maximum difference in carbon deposition on catalyst particles within a 1 / 2 bed height range from the distribution device is less than 3% by weight.

7. The method according to claim 5, characterized in that, The maximum difference in carbon deposition on catalyst particles within a range of 1 / 2 bed height from the distribution device is greater than 0.1% by weight.

8. A method for producing low-carbon olefins from oxygen-containing compounds, comprising the step of contacting an oxygen-containing compound feedstock with a molecular sieve catalyst in a fluidized bed reaction zone to generate ethylene and / or propylene products under effective conditions; The raw material is introduced into the reaction zone of the fluidized bed reactor via a distribution device, characterized in that... The maximum difference in carbon deposition on catalyst particles within a range of 1 / 2 bed height from the distribution device is less than 8% by weight.

9. The method according to claim 8, characterized in that, The maximum difference in carbon deposition on catalyst particles within a 1 / 2 bed height range from the distribution device is less than 3% by weight.

10. The method according to claim 8 or 9, characterized in that, The maximum difference in carbon deposition on catalyst particles within a range of 1 / 2 bed height from the distribution device is greater than 0.1% by weight.

11. The method according to any one of claims 1-2 and 8-9, characterized in that, The oxygen-containing compound raw material includes methanol.

12. The method according to any one of claims 1-2 and 8-9, characterized in that, The molecular sieve is a silica-alumino-phosphorus molecular sieve.

13. The method according to claim 12, wherein the silicon-aluminum-phosphorus molecules are screened from SAPO-18, SAPO-34, SAPO-5, or combinations thereof.

14. The method according to any one of claims 1-2 and 8-9, characterized in that, The fluidized bed reaction zone is a dense phase, turbulent, or rapidly fluidized type.

15. The method according to any one of claims 1-2 and 8-9, characterized in that, The effective conditions include: reaction temperature of 400–550°C and reaction pressure of 0–1 MPaG.

16. The method according to any one of claims 1-2 and 8-9, characterized in that, The catalyst with a coke deposition of less than 3% by weight is uniformly distributed within the fluidized bed reaction zone.

17. The method according to any one of claims 1-2 and 8-9, characterized in that, The gas phase and catalyst in the fluidized bed reaction zone are rapidly separated by a separation device after the reaction is completed or after leaving the fluidized bed reaction zone.

18. The method according to any one of claims 1-2 and 8-9, wherein the raw material enters the reaction zone of the fluidized bed reactor via a distribution device, and the maximum difference in carbon deposition on the catalyst particles within a 1 / 2 bed height range from the distribution device is less than 8% by weight, characterized in that... After the catalyst in the reaction zone is deactivated, it forms a dormant catalyst. The dormant catalyst enters the regenerator through the dormant pipeline for regeneration, forming a regenerated catalyst. The regenerated catalyst is returned to the fluidized bed reaction zone through the regeneration pipeline. The ratio of the regenerated catalyst to the dormant catalyst in the reaction zone is controlled to be 0.01 to 1. The amount of coke deposited on the regenerated catalyst is 0 to 5% by weight.

19. The method according to claim 18, characterized in that, The ratio of regenerated catalyst to unregenerated catalyst in the reaction zone is controlled to be 0.07–0.3; the amount of coke deposited on the regenerated catalyst is 0.5–2% by weight.

20. The method according to claim 18, characterized in that, The difference in coke deposits between the spent catalyst and the regenerated catalyst shall not exceed 7% by weight.

21. The method according to claim 20, characterized in that, The difference in coke deposits between the spent catalyst and the regenerated catalyst shall not exceed 5% by weight.

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