CN113385113A - Method for improving yield of ethylene and propylene and fluidized bed reactor - Google Patents

Abstract

The invention relates to a method for improving the yield of ethylene and propylene and a fluidized bed reactor, which mainly solve the problem of lower yield of ethylene and propylene in the prior art. The method comprises the steps that a raw material of methanol enters a fluidized bed reaction zone and contacts with a catalyst comprising a silicoaluminophosphate molecular sieve to generate a product material flow comprising ethylene and propylene, and a spent catalyst is formed at the same time; at least one part of the spent catalyst enters a regenerator for regeneration to form a regenerated catalyst; the regenerated catalyst returns to the reaction zone through a regeneration pipeline; wherein the reaction zone at least comprises a shape-selective zone and a transformation zone, the shape-selective zone is positioned at the lower part of the reaction zone, and the transformation zone is positioned at the upper part of the reaction zone; the connection part of the shape selecting area and the transformation area is provided with distribution equipment; the reforming zone is provided with the regeneration line inlet at least on the bottom side wall. The method can be used for the industrial production of ethylene and propylene.

Description

Method for improving yield of ethylene and propylene and fluidized bed reactor

Technical Field

The invention relates to a method for improving the yield of ethylene and propylene and a fluidized bed reactor.

Background

Light olefins, i.e. ethylene and propylene, are two important basic chemical raw materials, and the demand of the light olefins is increasing. Generally, ethylene and propylene are produced through petroleum routes, but the cost of producing ethylene and propylene from petroleum resources is increasing due to the limited supply and high price of petroleum resources. In recent years, technologies for producing ethylene and propylene by conversion of raw materials have been developed vigorously. Among them, an important alternative raw material for producing low-carbon olefins is an oxygen-containing compound, such as alcohols (methanol and ethanol), ethers (dimethyl ether and methyl ethyl ether), esters (dimethyl carbonate and methyl formate), and the oxygen-containing compound can be converted from energy sources such as coal, natural gas and biomass. Certain oxygenates have been produced on a larger scale, such as methanol, from coal or natural gas, and the process is well established and can be produced on a megaton scale. Due to the wide availability of oxygenate sources, coupled with the economics of the conversion to lower olefins, processes for the conversion of Oxygenates To Olefins (OTO), particularly Methanol To Olefins (MTO), have received increasing attention.

Document US4499327 makes detailed studies on the application of silicoaluminophosphate molecular sieve catalyst to the process of preparing olefin by methanol conversion, and considers SAPO-34 as the first catalyst of MTO process. The SAPO-34 catalyst has high selectivity of low-carbon olefin and high activity.

In addition, as is known in the art, in order to ensure high selectivity of low-carbon olefins, a certain amount of carbon needs to be deposited on the SAPO-34 catalyst, the catalyst alcohol ratio of the MTO process is small, the coke rate is low, and in order to achieve a large and easily controlled catalyst circulation amount, the carbon deposition on the catalyst needs to be controlled to a certain level in the regeneration zone, so as to achieve the purpose of controlling the average carbon deposition of the catalyst in the reaction zone. Therefore, how to control the average carbon deposit amount of the catalyst in the reaction zone to a certain level is critical in the MTO technology.

Document US6166282 discloses a technique and reactor for converting methanol into low carbon olefins, which uses a fast fluidized bed reactor, after the gas phase is reacted in a dense phase reaction zone with lower gas velocity, the gas phase rises to a fast partition zone with rapidly reduced inner diameter, and a special gas-solid separation device is used for primarily separating most entrained catalyst. Because the product gas and the catalyst are quickly separated after the reaction, the occurrence of secondary reaction is effectively prevented. The yield of the low carbon olefin carbon group in the method is generally about 77 percent.

Document CN1723262A discloses a multi-stage riser reactor with a central catalyst loop for the process of converting oxides into lower olefins, which comprises a plurality of riser reactors, a gas-solid separation zone, a plurality of offset elements, etc., each of the riser reactors has a port for injecting catalyst, and the ports converge to the separation zone to separate the catalyst from the product gas. The yield of the low-carbon olefin carbon base in the method is generally 75-80%.

However, with the increasing demand of ethylene and propylene in the market, higher requirements are put on the production technology of the low-carbon olefin.

Disclosure of Invention

In the process of converting methanol into low-carbon olefin, a certain amount of carbon deposition on a catalyst is necessary for ensuring high selectivity of the low-carbon olefin, and in a fluidized bed reactor, catalyst circulation between reaction and regeneration exists, so that the problem that a plurality of strands of catalysts are mixed inevitably exists in a reaction zone, and the carbon deposition amount of the catalysts in the reaction zone is an average concept. By adopting the technical scheme of the invention, the reaction zone is divided into an upper zone and a lower zone, in the shape selective zone at the bottom, the methanol raw material is contacted with the catalyst with higher carbon deposition amount to generate olefin with high selectivity, and then the residual methanol is converted by the catalyst with high activity in the conversion zone. The parameter setting of the shape-selective area and the conversion area is crucial, such as the diameter ratio, the height ratio, the density ratio and the like, and the inventor obtains the technical scheme of the invention through optimization, so that the high methanol conversion rate can be ensured, the high low-carbon olefin selectivity can be ensured, the selectivity can reach more than 85 percent, and a better technical effect is achieved.

In particular, the present invention relates to the following aspects:

1. a method for improving the yield of ethylene and propylene comprises the steps that a raw material of methanol enters a reaction zone of a fluidized bed and contacts with a catalyst comprising a silicoaluminophosphate molecular sieve to generate a product material flow comprising ethylene and propylene, and a spent catalyst is formed at the same time; at least one part of the spent catalyst enters a regenerator for regeneration to form a regenerated catalyst; the regenerated catalyst returns to the reaction zone through a regeneration pipeline; wherein the reaction zone at least comprises a shape-selective zone and a transformation zone, the shape-selective zone is positioned at the lower part of the reaction zone, and the transformation zone is positioned at the upper part of the reaction zone; the connection part of the shape selecting area and the transformation area is provided with distribution equipment; the reforming zone is provided with the regeneration line inlet at least on the bottom side wall.

2. The method for increasing the yield of ethylene and propylene according to claim 1, wherein the ratio of the height of the shape selective zone to the height of the transformation zone is 1-5: 1, preferably 1-3: 1, and more preferably 1-2: 1.

3. The process for increasing the yield of ethylene and propylene according to any one of claims 1-2, wherein the ratio of the diameter of the shape selective zone to the diameter of the reforming zone is 0.5 to 1.5:1, preferably 0.8 to 1.5:1, more preferably 1 to 1.5: 1.

4. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 3, wherein the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 1 to 10:1, preferably 1.5 to 8:1, more preferably 2 to 5: 1.

5. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 4, wherein the activity index of the regenerated catalyst is greater than 0.7, preferably greater than 0.8, and more preferably greater than 0.9.

6. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 5, wherein 20 to 50 percent of the weight of the spent catalyst, preferably 25 to 45 percent of the weight of the spent catalyst, and more preferably 30 to 40 percent of the weight of the spent catalyst are regenerated in a regenerator; and returning 50-80%, preferably 55-75% and more preferably 60-70% of the spent catalyst by weight to the shape selective area.

7. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 6, wherein the superficial linear velocity of the gas in the reaction zone is 0.9-7 m/s, preferably 1.0-4 m/s, more preferably 1.2-2.5 m/s

8. The method for increasing the yield of ethylene and propylene as claimed in any one of claims 1 to 6, wherein the reaction conditions in the reaction zone comprise: the reaction pressure is 0.01-0.5 MPa, preferably 0.1-0.3 MPa; the average temperature of the reaction zone is 400-550 ℃, and preferably 450-500 ℃; the carbon deposition amount of the catalyst in the shape selective zone is 3.0-10.0 wt%, preferably 3.5-8.0 wt%, and more preferably 4.0-6.5 wt%; the carbon deposition amount of the catalyst in the conversion zone is 2.0-9.0 wt%, preferably 2.5-7.0 wt%, and more preferably 3.0-5.5 wt%.

9. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 8, wherein the silicoaluminophosphate molecular sieve is at least one selected from the group consisting of SAPO-18 and SAPO-34, preferably SAPO-34.

10. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 9, wherein the fluidized bed reaction zone is in the form of a fast fluidized bed.

11. The method for increasing the yield of ethylene and propylene according to any one of claims 1-10, wherein the shape selective zone outlet methanol conversion rate is controlled to be more than 80%, and the selectivity of the lower olefins is controlled to be more than 70%.

12. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 11, wherein the conversion of methanol at the outlet of the conversion zone is controlled to be more than 98%.

13. The method for improving the yield of the ethylene and the propylene as claimed in any one of claims 1 to 12, wherein a gas-solid rapid separation device is arranged at the outlet of the conversion zone.

14. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 13, wherein the inlet of the regeneration pipeline is provided with a catalyst distributor, and the catalyst distributor is arranged substantially horizontally along the radial direction of the fluidized bed reaction zone.

15. A fluidized bed reactor comprising a reaction zone, the reaction zone comprising at least a shape selective zone and a conversion zone; the shape-selective area is positioned at the lower part of the reaction area, and the transformation area is positioned at the upper part of the reaction area; the connection part of the shape selecting area and the transformation area is provided with distribution equipment; the reforming zone is provided with a regeneration line inlet at least on the bottom side wall.

16. The fluidized bed of claim 15, wherein the ratio of the height of the shape selective zone to the height of the reforming zone is 1 to 5:1, preferably 1 to 3:1, more preferably 1 to 2: 1.

17. The fluidized bed of any one of claims 15-16, wherein the ratio of the diameter of the shape selective zone to the diameter of the reforming zone is 0.5 to 1.5:1, preferably 0.8 to 1.5:1, more preferably 1 to 1.5: 1.

18. The fluidized bed of any one of claims 15-17, wherein the outlet of the conversion zone is equipped with a gas-solid rapid separation device.

19. The method for improving the yield of ethylene and propylene according to any one of claims 15 to 18, wherein the inlet of the regeneration pipeline is provided with a catalyst distributor, and the catalyst distributor is arranged substantially horizontally along the radial direction of the fluidized bed reaction zone.

Technical effects

According to the invention, not only can the high conversion rate of raw materials be ensured, but also the high selectivity of the low-carbon olefin can be ensured.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention.

In the context of figure 1 of the drawings,

1 is used as raw material feed;

2 is a shape-selective area;

3 is a gas-solid rapid separation device;

4 is a stripping zone;

5 is a spent catalyst circulating inclined tube;

6 is a to-be-grown inclined tube;

7 is a heat exchanger;

8 is a gas-solid cyclone separator;

9 is a reactor separation zone;

10 is a product gas collection chamber;

11 is a product gas outlet pipeline;

12 is a regeneration pipeline;

13 is a transformation zone;

and 14 is a distribution device at the junction of the shape selective zone and the transformation zone.

Detailed Description

The following detailed description of the embodiments of the present invention is provided, but it should be noted that the scope of the present invention is not limited by the embodiments, but is defined by the appended claims.

All publications, patent applications, patents, and other references mentioned in this specification are herein incorporated by reference in their entirety. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present specification, including definitions, will control.

When the specification concludes with claims with the heading "known to those skilled in the art", "prior art", or the like, to derive materials, substances, methods, procedures, devices, or components, etc., it is intended that the subject matter derived from the heading encompass those conventionally used in the art at the time of filing this application, but also include those that are not currently in use, but would become known in the art to be suitable for a similar purpose.

In the context of this specification, the word "substantially" means that a deviation within ± 10%, within ± 5%, within ± 1%, within ± 0.5% or within ± 0.1% is allowed, which is acceptable or considered reasonable by a person skilled in the art.

All percentages, parts, ratios, etc. referred to in this specification are by weight and pressures are gauge pressures unless otherwise specifically indicated.

In the context of this specification, any two or more embodiments of the invention may be combined in any combination, and the resulting solution is part of the original disclosure of this specification, and is within the scope of the invention.

In the context of the present specification, the term "reaction zone" is used with reference to a fluidized bed reactor. Desirably, the fluidized bed reactor includes a reaction zone, an inlet zone, and a disengaging zone. The "inlet zone" is the zone in the reactor where the feedstock and catalyst are introduced. A "reaction zone" is a zone in a reactor where a feed is contacted with a catalyst under conditions effective to convert the oxygenate of the feed to light olefin products. The "disengaging zone" is the zone in the reactor where the catalyst and any other solids within the reactor are separated from the product. Typically, the reaction zone is located between the inlet zone and the separation zone.

In the context of this specification, the catalyst carbon deposit amount (or average carbon deposit amount) is calculated as the mass of carbon deposit on the catalyst divided by the mass of the catalyst. The method for measuring the quality of the carbon deposit on the catalyst comprises the following steps: weighing 0.1-1 g of carbon-containing catalyst, placing the carbon-containing catalyst in a high-temperature carbon analyzer for combustion, and measuring the mass of carbon dioxide generated by combustion through infrared rays to obtain the mass of carbon deposit on the catalyst. In order to determine the amount of catalyst fouling in the reaction zone, equal aliquots of catalyst may be withdrawn continuously or periodically or directly from various locations in the reaction zone.

In the context of the present specification, the term "regenerated catalyst activity index" is used to indicate the degree of regeneration of a deactivated catalyst, relative comparisons being made, based on fresh catalyst, with the amount of methanol converted by each catalyst under fixed conditions, calculated as: the regenerated catalyst activity index (amount of methanol converted from regenerated catalyst under certain conditions/amount of methanol converted from fresh catalyst under certain conditions) × 100%.

20-50% of the weight of the spent catalyst, preferably 25-40%, is regenerated by a regenerator; 50-80%, preferably 60-75% of the weight of the spent catalyst returns to the shape-selective area through a spent catalyst circulating inclined pipe.

The present invention will be described in further detail below by way of examples and comparative examples, but the present invention is not limited to the following examples.

[ example 1 ]

As shown in figure 1, a methanol raw material enters a shape selecting zone 2 through a feeding pipeline 1, contacts with a molecular sieve catalyst, reacts to generate a gas-phase product containing ethylene and propylene, the gas-phase product carries a catalyst to be generated and enters a reactor separation zone 9 through a gas-solid rapid separation device 3, wherein most of the catalyst separated by the gas-solid rapid separation device 3 enters a stripping zone 4, the gas-phase product and part of the catalyst which is not separated by the gas-solid rapid separation device 3 enter a cyclone separator 8 for re-separation, the catalyst returns to the stripping zone 4 through a dipleg of the cyclone separator 8, and the gas-phase product enters a gas collection chamber 10 and then enters a subsequent separation section through an outlet pipeline 11. The spent catalyst separated by the gas-solid rapid separation device 3 and the cyclone separator 8 is at least divided into two parts after steam stripping, one part returns to the bottom of the reaction zone 2 through the catalyst circulation inclined tube 5 after heat exchange by the heat exchanger 7, the other part enters the regenerator through the spent inclined tube 6 to be burned for regeneration, and the regenerated catalyst returns to the conversion zone 13 through the regeneration inclined tube 12. A gas-solid rapid separation device is arranged at the outlet of the conversion zone; the regenerated catalyst returns to the reaction zone through a regenerated catalyst pipeline, a catalyst distributor is arranged at the outlet of the regenerated catalyst pipeline, the distributor is horizontally arranged along the radial direction of the fluidized bed reactor, and the regenerated catalyst is uniformly distributed on the radial plane of the reaction zone of the fluidized bed reactor; and a distribution device is arranged at the joint of the shape selecting area and the transformation area.

The average temperature of the reaction zone was 500 ℃, the reaction pressure was 0.1MPa in terms of gauge pressure, pure methanol was fed, the catalyst type is shown in table 1, the stripping medium of the stripping zone was steam, the gas superficial linear velocity in the reaction zone was 1.5 m/s, the carbon deposition amount of the catalyst in the shape-selective zone was 5.0 wt%, and the carbon deposition amount of the catalyst in the reforming zone was 4.0 wt%. The spent catalyst is divided into two parts, 40 percent of the spent catalyst is regenerated in a regenerator, 60 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.87, and the height ratio of the shape selective zone to the conversion zone is 1: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 2: 1; the diameter ratio of the shape selective zone to the conversion zone was 1:1, the conversion of methanol at the outlet of the shape selective zone was 85% and the conversion of methanol at the outlet of the conversion zone was 99.8% by sampling analysis, the stability of catalyst flow control was maintained, the product at the outlet of the reactor was analyzed by on-line gas chromatography, and the reaction results are shown in table 1.

TABLE 1

Parameter(s)	Catalyst type	Yield of carbon-based low-carbon olefin
			Example 1	SAPO-18	80.27
Example 2	SAPO-34	83.45

[ example 3 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 400 ℃, the reaction pressure was 0.1MPa by gauge pressure, pure methanol was fed, the stripping medium in the stripping zone was steam, the superficial linear velocity of the gas in the reaction zone was 0.9 m/s, the amount of carbon deposition of the catalyst in the shape selective zone was 3.0 wt%, and the amount of carbon deposition of the catalyst in the reforming zone was 2.0 wt%. The spent catalyst is divided into two parts, 50 percent of the spent catalyst is regenerated in a regenerator, 50 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.97, and the height ratio of the shape selective zone to the conversion zone is 0.8: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 1: 1; the diameter ratio of the shape selective area to the conversion area is 0.8:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 81%, the conversion rate of methanol at the outlet of the conversion area is 99.87%, the stability of catalyst flow control is kept, products at the outlet of a reactor are analyzed by an online gas chromatography, and the reaction result is as follows: the carbon-based yield of the low-carbon olefin is 82.09 percent by weight.

[ example 4 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 550 ℃, the reaction pressure was 0.5MPa by gauge pressure, pure methanol was fed, the stripping medium in the stripping zone was steam, the superficial linear velocity of the gas in the reaction zone was 4 m/s, the amount of catalyst carbon deposition in the shape selective zone was 10.0 wt%, and the amount of catalyst carbon deposition in the reforming zone was 9.0 wt%. The spent catalyst is divided into two parts, 50 percent of the spent catalyst is regenerated in a regenerator, 50 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.93, and the height ratio of the shape selective zone to the conversion zone is 2: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 2: 1; the diameter ratio of the shape selective area to the conversion area is 1.5:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 85%, the conversion rate of methanol at the outlet of the conversion area is 99.76%, the stability of catalyst flow control is kept, products at the outlet of a reactor are analyzed by an online gas chromatography, and the reaction result is as follows: the carbon-based yield of the low-carbon olefin is 83.11 percent by weight.

[ example 5 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 530 ℃, the reaction pressure was 0.3MPa in gauge pressure, pure methanol was fed, the stripping medium in the stripping zone was steam, the superficial linear velocity of the gas in the reaction zone was 2.5 m/s, the amount of catalyst carbon deposition in the shape selective zone was 8.0 wt%, and the amount of catalyst carbon deposition in the reforming zone was 6.5 wt%. The spent catalyst is divided into two parts, 40 percent of the spent catalyst is regenerated in a regenerator, 60 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.93, and the height ratio of the shape selective zone to the conversion zone is 5: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 8: 1; the diameter ratio of the shape selective area to the conversion area is 1:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 90%, the conversion rate of methanol at the outlet of the conversion area is 99.94%, the stability of catalyst flow control is kept, products at the outlet of a reactor are analyzed by an online gas chromatography, and the reaction result is as follows: the carbon-based yield of the low-carbon olefin is 83.35 percent by weight.

[ example 6 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 500 ℃, the reaction pressure was 0.15MPa by gauge pressure, pure methanol was fed, the stripping medium in the stripping zone was steam, the superficial linear velocity of the gas in the reaction zone was 1.5 m/s, the amount of catalyst carbon deposition in the shape selective zone was 3.5 wt%, and the amount of catalyst carbon deposition in the reforming zone was 2.5 wt%. The spent catalyst is divided into two parts, 40 percent of the spent catalyst is regenerated in a regenerator, 60 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.86, and the height ratio of the shape selective zone to the conversion zone is 1.5: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 5: 1; the diameter ratio of the shape selective area to the conversion area is 1:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 93%, the conversion rate of methanol at the outlet of the conversion area is 99.99%, the stability of catalyst flow control is kept, products at the outlet of a reactor are analyzed by an online gas chromatography, and the reaction result is as follows: the carbon-based yield of the low-carbon olefin is 84.09 percent by weight.

[ example 7 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 480 ℃, the reaction pressure was 0.15MPa by gauge pressure, pure methanol was fed, the stripping medium in the stripping zone was steam, the superficial linear velocity of the gas in the reaction zone was 1.5 m/s, the amount of catalyst carbon deposition in the shape selective zone was 4.0 wt%, and the amount of catalyst carbon deposition in the reforming zone was 3.5 wt%. The spent catalyst is divided into two parts, 30 percent of the spent catalyst is regenerated in a regenerator, 70 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.9, and the height ratio of the shape selective zone to the conversion zone is 1.2: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 2: 1; the diameter ratio of the shape selective area to the conversion area is 1:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 86%, the conversion rate of methanol at the outlet of the conversion area is 99.89%, the stability of catalyst flow control is kept, products at the outlet of a reactor are analyzed by an online gas chromatography, and the reaction result is as follows: the carbon-based yield of the low-carbon olefin is 84.33 percent by weight.

[ example 8 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 480 ℃, the reaction pressure was 0.15MPa by gauge pressure, pure methanol was fed, the stripping medium in the stripping zone was steam, the superficial linear velocity of the gas in the reaction zone was 1.5 m/s, the amount of catalyst carbon deposition in the shape selective zone was 4.0 wt%, and the amount of catalyst carbon deposition in the reforming zone was 2.5 wt%. The spent catalyst is divided into three parts, wherein 50 percent of the spent catalyst is regenerated in a regenerator, and the rest 50 percent of the spent catalyst is averagely divided into two parts and returns to the bottom of the reaction zone through a spent catalyst circulating inclined tube. The regenerated catalyst activity index is 0.9, and the ratio of the height of the shape selective zone to the height of the conversion zone is 0.8: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 1: 1; the diameter ratio of the shape selective area to the conversion area is 0.5:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 80%, the conversion rate of methanol at the outlet of the conversion area is 99.54%, the stability of catalyst flow control is kept, products at the outlet of a reactor are analyzed by an online gas chromatography, and the reaction result is as follows: the carbon-based yield of the low-carbon olefin is 83.26 percent by weight.

[ example 9 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 480 ℃, the reaction pressure was 0.15MPa in gauge pressure, the superficial linear velocity of the gas in the reaction zone was 1.5 m/s, the amount of catalyst carbon deposition in the shape selective zone was 4.0 wt%, and the amount of catalyst carbon deposition in the reforming zone was 2.5 wt%. The spent catalyst is divided into two parts, 20 percent of the spent catalyst is regenerated in a regenerator, 80 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.94, and the height ratio of the shape selective zone to the conversion zone is 2: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 3: 1; the diameter ratio of the shape selective area to the conversion area is 0.8:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 83%, the conversion rate of methanol at the outlet of the conversion area is 99.9%, the stability of catalyst flow control is kept, and the yield of low-carbon olefin carbon base is 85.97% (by weight) by adopting on-line gas chromatography analysis on products at the outlet of the reactor.

[ example 10 ]

According to the conditions and procedures described in [ example 2 ], the average temperature in the reaction zone was 480 ℃, the reaction pressure was 0.15MPa in gauge pressure, the superficial linear velocity of the gas in the reaction zone was 1.5 m/s, the amount of catalyst carbon deposition in the shape selective zone was 4.0 wt%, and the amount of catalyst carbon deposition in the reforming zone was 2.5 wt%. The spent catalyst is divided into two parts, 20 percent of the spent catalyst is regenerated in a regenerator, 80 percent of the spent catalyst returns to the bottom of the reaction zone, the activity index of the regenerated catalyst is 0.89, and the height ratio of the shape selective zone to the conversion zone is 2: 1; the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 2: 1; the diameter ratio of the shape selective area to the conversion area is 1.5:1, through sampling analysis, the conversion rate of methanol at the outlet of the shape selective area is 87%, the conversion rate of methanol at the outlet of the conversion area is 99.99%, the stability of catalyst flow control is kept, and the yield of low-carbon olefin carbon base is 85.36% (by weight) by adopting on-line gas chromatography analysis on products at the outlet of a reactor.

[ COMPARATIVE EXAMPLE 1 ]

According to the conditions and procedures described in example 2, except that the regenerated catalyst was directly returned to the bottom of the reaction zone through the regenerated inclined tube, the catalyst in the reaction zone of the reactor was in a fully back-mixed state, there was no difference between the shape-selective zone and the conversion zone in the reaction zone, and the yield of carbon based low-carbon olefin at the outlet of the reactor was 80.87 wt%.

[ COMPARATIVE EXAMPLE 2 ]

According to the conditions and procedures described in example 2, only the regenerated catalyst directly returns to the bottom of the reaction zone through the regeneration inclined tube, the reaction zone of the reactor is a fast fluidized bed, the shape-selective zone and the conversion zone are not arranged in the reaction zone, and the carbon-based yield of the low-carbon olefin at the outlet of the reactor is 81.52% (by weight).

[ COMPARATIVE EXAMPLE 3 ]

According to the conditions and procedures described in example 2, the reaction zone of the reactor was a fast fluidized bed, and the reaction zone was not divided into a shape-selective zone and a conversion zone, except that the regenerated catalyst was returned to the middle of the reaction zone through a regeneration inclined tube, and the yield of carbon based low-carbon olefin at the outlet of the reactor was 82.09 wt%.

Obviously, the method can achieve the purpose of improving the yield of the carbon group of the ethylene and the propylene, has greater technical advantages and can be used for the industrial production of the ethylene and the propylene.

Claims (19)

1. A method for improving the yield of ethylene and propylene comprises the steps that a raw material of methanol enters a reaction zone of a fluidized bed and contacts with a catalyst comprising a silicoaluminophosphate molecular sieve to generate a product material flow comprising ethylene and propylene, and a spent catalyst is formed at the same time; at least one part of the spent catalyst enters a regenerator for regeneration to form a regenerated catalyst; the regenerated catalyst returns to the reaction zone through a regeneration pipeline; wherein the reaction zone at least comprises a shape-selective zone and a transformation zone, the shape-selective zone is positioned at the lower part of the reaction zone, and the transformation zone is positioned at the upper part of the reaction zone; the connection part of the shape selecting area and the transformation area is provided with distribution equipment; the reforming zone is provided with the regeneration line inlet at least on the bottom side wall.

2. The method for increasing the yield of ethylene and propylene according to claim 1, wherein the ratio of the height of the shape selective zone to the height of the transformation zone is 1-5: 1, preferably 1-3: 1, and more preferably 1-2: 1.

3. The process for increasing the yield of ethylene and propylene according to any one of claims 1-2, wherein the ratio of the diameter of the shape selective zone to the diameter of the reforming zone is 0.5 to 1.5:1, preferably 0.8 to 1.5:1, more preferably 1 to 1.5: 1.

4. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 3, wherein the ratio of the catalyst density in the shape selective zone to the catalyst density in the conversion zone is 1 to 10:1, preferably 1.5 to 8:1, more preferably 2 to 5: 1.

5. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 4, wherein the activity index of the regenerated catalyst is greater than 0.7, preferably greater than 0.8, and more preferably greater than 0.9.

6. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 5, wherein 20 to 50 percent of the weight of the spent catalyst, preferably 25 to 45 percent of the weight of the spent catalyst, and more preferably 30 to 40 percent of the weight of the spent catalyst are regenerated in a regenerator; and returning 50-80%, preferably 55-75% and more preferably 60-70% of the spent catalyst by weight to the shape selective area.

7. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 6, wherein the superficial linear velocity of the gas in the reaction zone is 0.9 to 7 m/s, preferably 1.0 to 4 m/s, and more preferably 1.2 to 2.5 m/s.

8. The method for increasing the yield of ethylene and propylene as claimed in any one of claims 1 to 6, wherein the reaction conditions in the reaction zone comprise: the reaction pressure is 0.01-0.5 MPa, preferably 0.1-0.3 MPa; the average temperature of the reaction zone is 400-550 ℃, and preferably 450-500 ℃; the carbon deposition amount of the catalyst in the shape selective zone is 3.0-10.0 wt%, preferably 3.5-8.0 wt%, and more preferably 4.0-6.5 wt%; the carbon deposition amount of the catalyst in the conversion zone is 2.0-9.0 wt%, preferably 2.5-7.0 wt%, and more preferably 3.0-5.5 wt%.

9. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 8, wherein the silicoaluminophosphate molecular sieve is at least one selected from the group consisting of SAPO-18 and SAPO-34, preferably SAPO-34.

10. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 9, wherein the fluidized bed reaction zone is in the form of a fast fluidized bed.

11. The method for increasing the yield of ethylene and propylene according to any one of claims 1-10, wherein the shape selective zone outlet methanol conversion rate is controlled to be more than 80%, and the selectivity of the lower olefins is controlled to be more than 70%.

12. The method for increasing the yield of ethylene and propylene according to any one of claims 1 to 11, wherein the conversion of methanol at the outlet of the conversion zone is controlled to be more than 98%.

13. The method for improving the yield of the ethylene and the propylene as claimed in any one of claims 1 to 12, wherein a gas-solid rapid separation device is arranged at the outlet of the conversion zone.

14. The method for improving the yield of ethylene and propylene according to any one of claims 1 to 13, wherein the inlet of the regeneration pipeline is provided with a catalyst distributor, and the catalyst distributor is arranged substantially horizontally along the radial direction of the fluidized bed reaction zone.

15. A fluidized bed reactor comprising a reaction zone, the reaction zone comprising at least a shape selective zone and a conversion zone; the shape-selective area is positioned at the lower part of the reaction area, and the transformation area is positioned at the upper part of the reaction area; the connection part of the shape selecting area and the transformation area is provided with distribution equipment; the reforming zone is provided with a regeneration line inlet at least on the bottom side wall.

16. The fluidized bed of claim 15, wherein the ratio of the height of the shape selective zone to the height of the reforming zone is 1 to 5:1, preferably 1 to 3:1, more preferably 1 to 2: 1.

17. The fluidized bed of any one of claims 15-16, wherein the ratio of the diameter of the shape selective zone to the diameter of the reforming zone is 0.5 to 1.5:1, preferably 0.8 to 1.5:1, more preferably 1 to 1.5: 1.

18. The fluidized bed of any one of claims 15-17, wherein the outlet of the conversion zone is equipped with a gas-solid rapid separation device.

19. The method for improving the yield of ethylene and propylene according to any one of claims 15 to 18, wherein the inlet of the regeneration pipeline is provided with a catalyst distributor, and the catalyst distributor is arranged substantially horizontally along the radial direction of the fluidized bed reaction zone.

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