CN107043317B

CN107043317B - Device and method for preparing olefin from methanol

Info

Publication number: CN107043317B
Application number: CN201710286100.9A
Authority: CN
Inventors: 文尧顺; 闫国春; 关丰忠; 南海明; 卢卫民
Original assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Current assignee: China Shenhua Coal to Liquid Chemical Co Ltd; Shenhua Group Corp Ltd
Priority date: 2017-04-26
Filing date: 2017-04-26
Publication date: 2020-05-01
Anticipated expiration: 2037-04-26
Also published as: CN107043317A

Abstract

The invention provides a device and a method for preparing olefin from methanol. The device comprises at least two reactors, a regenerator and at least two rapid cooling water washing devices, wherein each reactor is provided with a spent catalyst outlet, a regenerated catalyst inlet and a product gas outlet; the regenerator is provided with a spent catalyst inlet and a regenerated catalyst outlet, the spent catalyst inlet is respectively communicated with each spent catalyst outlet, and the regenerated catalyst outlet is respectively communicated with each regenerated catalyst inlet; the quenching water washing device is in one-to-one correspondence with the reactors, a product gas inlet is formed in the quenching water washing device, and the product gas inlet is communicated with the corresponding product gas outlets respectively. The device makes full use of the characteristics of small load of the regenerator, large load of the reactor and small catalyst circulation amount in the process of preparing the olefin from the methanol, and a plurality of reactors share one regenerator, thereby greatly improving the capacity of a single set of device for preparing the olefin from the methanol.

Description

Device and method for preparing olefin from methanol

Technical Field

The invention relates to the field of chemical industry, and particularly relates to a device and a method for preparing olefin from methanol.

Background

The low-carbon olefins such as ethylene, propylene and the like are the most basic chemical raw materials, and particularly, the production capacity of ethylene is one of the marks for measuring the chemical level of a country and a region. At present, the main production modes of ethylene and propylene comprise a cracking technology using petroleum as a raw material, a technology for preparing olefin from methanol, a technology for preparing propylene from methanol, a propane dehydrogenation technology and the like, and industrialization is already formed. The petroleum resources in China are seriously in short supply, and the external dependence of petroleum reaches 60% in 2015, which seriously affects the energy strategic safety in China. The ethylene propylene production route using petroleum base as a source consumes valuable petroleum resources, and the coal resources in China are abundant, so that the development of the coal-based olefin production route has important significance. On one hand, the consumption of petroleum resources is reduced, and on the other hand, the utilization efficiency and the economic value of coal are improved. The technical route of the coal-based olefin is as follows: coal gasification, synthesis gas purification, methanol preparation from synthesis gas, olefin preparation from methanol, olefin separation and olefin polymerization to produce polyethylene and polypropylene. At present, the methanol yield in China is relatively excessive, the methanol market is low, the low-carbon olefin produced by converting methanol can relieve the shortage of the ethylene propylene market and improve the economic benefit of methanol production enterprises.

The preparation of low-carbon olefin by methanol conversion (the preparation of olefin from methanol) usually adopts a silicoaluminophosphate molecular sieve microspherical catalyst, the main active component of which is an SAPO-34 molecular sieve, and the catalyst can generate carbon deposition in the reaction process to block the pore channel of the molecular sieve, so that the catalytic activity of the molecular sieve is reduced. The catalyst needs to be periodically regenerated, the carbon deposit on the surface of the catalyst is burnt, and the activity of the catalyst is recovered. Therefore, methanol to olefins processes all require a reactor and regenerator combination. Various methods and devices for preparing olefin from methanol are reported in domestic and foreign patents, and most of the methods and devices adopt a fluidized bed reactor and a fluidized bed regenerator.

At present, the maximum processing capacity of a methanol-to-olefin device which is operated, built and designed is 180 ten thousand tons of methanol per year, and the olefin production capacity is 60 ten thousand tons per year. The methanol-to-olefin apparatus provided with the carbon tetraolefin cracking or olefin disproportionation has an olefin production capacity of 68 ten thousand tons/year, and cannot achieve a megaton production scale, and cannot further bring the scale benefit and economic benefit of large-scale apparatus into play. Million-ton scale ethylene devices are generally configured for million-ton oil refining devices in petrochemical industry, and a plurality of million-ton ethylene production bases are already built in China. For example, at present, in China, a single set of ethylene device has the largest capacity, namely 90 ten thousand tons of ethylene devices in Shanghai Sico, the yield of the ethylene device is 100 ten thousand tons in 2007, 120 ten thousand tons in 2010 and 129.43 ten thousand tons in the current set of ethylene devices.

The production operation of megaton-level ethylene engineering in petrochemical industry shows that the energy consumption can be reduced and the energy efficiency and the economic benefit can be improved through the large-scale and intensive device. The methanol-to-olefin device generally adopts a fluidized bed reaction regeneration system, and simultaneously, the catalytic cracking device adopting the fluidized bed reaction regeneration system can reach 350 million tons/year in the domestic large scale, such as catalytic cracking devices of Guangxi petrochemical industry, Dalian petrochemical industry and Lanzhou petrochemical industry. The scale of a single set of catalytic cracking unit of the Bei Tang oil refinery reaches 600 ten thousand tons per year.

The process for preparing olefin from methanol and the catalytic cracking process both adopt a fluidized bed reaction regeneration system, and the molecular weight of the raw material of the methanol-to-olefin device is 32 which is far smaller than about 200 of the average molecular weight of the raw material of the catalytic cracking device. Meanwhile, as for the reaction product, the main products of the methanol-to-olefin are ethylene, propylene and other low-carbon hydrocarbons, and according to the reaction principle, the generated water accounts for about half of the composition of the product gas, and the average molecular weight of the product gas is smaller. The main products of the catalytic cracking unit are gasoline (C5-C11 hydrocarbon) and diesel oil (C11-C20), and the average molecular weight is large. Due to the feeding and product gas material properties of the methanol device, the scale of the current methanol-to-olefin device is difficult to further expand. From the large-scale view of equipment, the size of a methanol-to-olefin device reactor is close to the largest fluidized bed reactor size in China at present (the diameter of a regenerator of a 300 ten thousand ton catalytic cracking device is 12 m). This indicates that there are limitations in terms of manufacturing, equipment fluidization and stability from reactor equipment by increasing reactor size under current technology conditions. Therefore, due to the limitation of the processing capacity of the methanol-to-olefin reactor, it is difficult to further significantly increase the scale of the methanol-to-olefin apparatus.

Disclosure of Invention

The invention mainly aims to provide a methanol-to-olefin device and a method, which aim to solve the problem of insufficient processing capacity of the methanol-to-olefin device in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a methanol to olefin apparatus including: each reactor is provided with a spent catalyst outlet, a regenerated catalyst inlet and a product gas outlet; the regenerator is provided with a spent catalyst inlet and a regenerated catalyst outlet, the spent catalyst inlet is respectively communicated with each spent catalyst outlet, and the regenerated catalyst outlet is respectively communicated with each regenerated catalyst inlet; and at least two quenching water washing devices, wherein the quenching water washing devices are arranged in one-to-one correspondence with the reactors, product gas inlets are formed in the quenching water washing devices, and the product gas inlets are communicated with corresponding product gas outlets.

Furthermore, the device also comprises at least two spent catalyst stripper, the spent catalyst stripper and the reactor are arranged in a one-to-one correspondence manner, and the spent catalyst stripper is arranged on a pipeline which is communicated with a spent catalyst inlet and a spent catalyst outlet.

Furthermore, the device also comprises a regenerated catalyst stripper which is arranged on a pipeline communicated with the regenerated catalyst inlet and the regenerated catalyst outlet and is used for stripping the regenerated catalyst.

Furthermore, the regenerated catalyst stripper is provided with one regenerated catalyst stripper, the inlet of the regenerated catalyst stripper is communicated with the regenerated catalyst outlet, and the outlet of the regenerated catalyst stripper is respectively communicated with the regenerated catalyst inlets.

Furthermore, the number of the regenerated catalyst strippers is at least two, the regenerated catalyst strippers are arranged in one-to-one correspondence with the reactors, and the regenerated catalyst strippers are arranged on a pipeline communicated with a regenerated catalyst inlet and a regenerated catalyst outlet.

Furthermore, a first-stage cyclone separator and a second-stage cyclone separator which are connected in series are arranged in the reactor, the second-stage cyclone separator is positioned at the downstream of the first-stage cyclone separator, and a gas phase outlet of the second-stage cyclone separator is communicated with a product gas outlet.

Furthermore, the device also comprises at least two three-stage cyclone separators, the three-stage cyclone separators are arranged in one-to-one correspondence with the quenching water washing device, and the three-stage cyclone separators are arranged on a pipeline between the product gas outlet and the corresponding product gas inlet.

Further, the device also comprises a first heat collector which is used for recovering the reaction heat in the reactor.

Further, the device also comprises a second heat collector which is used for recovering the regeneration reaction heat in the regenerator.

Further, the first heat collector is an internal heat collector and/or an external heat collector; the second heat collector is an internal heat collector and/or an external heat collector.

According to another aspect of the present invention, there is provided a methanol to olefin process, comprising the steps of: carrying out a methanol-to-olefin reaction in at least two reactors to obtain product gas and a spent catalyst; introducing the spent catalysts generated in the reactors into the same regenerator for catalyst regeneration to obtain regenerated catalysts; returning the regenerated catalyst to each reactor to continue the reaction of preparing olefin from methanol; and introducing the product gas generated in each reactor into a quenching water washing device which is arranged in one-to-one correspondence with the reactors to carry out quenching water washing treatment.

The technical scheme of the invention provides a device for preparing olefin from methanol. The device comprises at least two reactors, a regenerator and at least two rapid cooling water washing devices, wherein each reactor is provided with a spent catalyst outlet, a regenerated catalyst inlet and a product gas outlet; the regenerator is provided with a spent catalyst inlet and a regenerated catalyst outlet, the spent catalyst inlet is respectively communicated with each spent catalyst outlet, and the regenerated catalyst outlet is respectively communicated with each regenerated catalyst inlet; the quenching water washing device is in one-to-one correspondence with the reactors, a product gas inlet is formed in the quenching water washing device, and the product gas inlet is communicated with the corresponding product gas outlets respectively.

The device of the invention makes full use of the characteristics of small load of the regenerator, large load of the reactor and small catalyst circulation amount in the process of preparing olefin from methanol, and a plurality of reactors share one regenerator. Therefore, the capacity of the single set of device for preparing olefin from methanol can be greatly improved. And utilize a regenerator and a plurality of rapid cooling water to wash the device in cooperation of a plurality of reactors, utilize the product gas that each reactor of different rapid cooling water washing device produced, can also improve product gas treatment effect to save equipment and area, also be favorable to practicing thrift the cost.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a schematic diagram of a methanol to olefins plant according to an embodiment of the present invention.

Wherein the figures include the following reference numerals:

10. a reactor; 20. a regenerator; 30. a quench water washing device; 40. spent catalyst stripper; 50. a regenerated catalyst stripper; 60. a second heat collector.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

As described in the background section, the methanol to olefin plant of the prior art has a problem of insufficient processing capacity.

In order to solve the problem, the invention provides a methanol-to-olefin device, as shown in fig. 1, the device comprises at least two reactors 10, a regenerator 20 and at least two rapid cooling water washing devices 30, wherein each reactor 10 is provided with a spent catalyst outlet, a regenerated catalyst inlet and a product gas outlet; the regenerator 20 is provided with a spent catalyst inlet and a regenerated catalyst outlet, the spent catalyst inlet is respectively communicated with each spent catalyst outlet, and the regenerated catalyst outlet is respectively communicated with each regenerated catalyst inlet; the quench water washing device 30 is arranged corresponding to the reactors 10 one by one, and the quench water washing device 30 is provided with a product gas inlet which is respectively communicated with the corresponding product gas outlets.

Analyzing the principle of the methanol-to-olefin process, the molecular weight of the methanol fed into the reactor 10 is 32, the product gas mainly comprises ethylene, propylene, water, ethane and the like, the methanol-to-olefin reaction is a reaction with increased mole number, and the mole number is increased by 1 to 2 times according to the distribution difference of the products. According to the chemical reaction equilibrium principle, the reaction with increased molecular number and low pressure are beneficial to improving the selectivity of the low-carbon olefin. Increasing the load on the methanol to olefins plant by increasing the pressure will result in a decrease in product selectivity. According to the limitation of reaction conditions (temperature, pressure and residence time), for a device for preparing 60 million tons of olefins from 180 million tons of methanol, the diameter of a dilute phase section of a reactor reaches more than 10m, and the diameter of the reactor needs to be increased, so that the device manufacturing is limited on one hand, and the fluidization quality of the reactor deteriorates along with the increase of the diameter, so that the selectivity of low-carbon olefins is reduced, and meanwhile, the risk of amplification exists in matched devices.

According to the reaction principle of preparing olefin from methanol, the coke yield in the process of preparing olefin from methanol is relatively low, the coke yield of a typical industrial methanol-to-olefin device is between 1.5 and 2.5wt percent, the coke burning load of a 180 ten thousand ton methanol feeding device is between 3 and 6 tons of coke per hour, and the catalyst circulation amount between a reactor and a regenerator is less than 200 t/h. According to the property difference of catalytic raw materials, the coke yield of a catalytic cracking device of 180 ten thousand tons/year is between 5 and 10 percent, the coke burning load is 18 tons per hour calculated according to 8 percent, the coke burning load is far larger than that of a methanol-to-olefin device, and the catalyst circulation volume is over 1000 t/h. Therefore, in the methanol to olefin apparatus, the load of the regenerator is small, the load of the reactor is large, and the corresponding reactor volume is large and the regenerator volume is small. The regenerator load also has a large lift space. The catalyst circulation capacity also has larger lifting space.

Based on the reasons, the device provided by the invention fully utilizes the characteristics of small load of the regenerator, large load of the reactor and small circulation amount of the catalyst in the process of preparing the olefin from the methanol, and a plurality of reactors share one regenerator. Therefore, the capacity of the single set of device for preparing olefin from methanol can be greatly improved. And utilize a regenerator and a plurality of rapid cooling water to wash the device in cooperation of a plurality of reactors, utilize the product gas that each reactor of different rapid cooling water washing device produced, can also improve product gas treatment effect to save equipment and area, also be favorable to practicing thrift the cost.

In a preferred embodiment, the apparatus further includes at least two spent catalyst strippers 40, the spent catalyst strippers 40 are disposed in one-to-one correspondence to the reactors 10, and the spent catalyst strippers 40 are disposed on a pipeline connecting a spent catalyst inlet and a spent catalyst outlet. The spent catalyst stripper 40 can be used for carbon deposition-steam contact of the spent catalyst from the spent catalyst outlet, and after the steam stripping is finished, the separated spent catalyst is introduced into the regenerator 10. This is advantageous in improving the regeneration efficiency of the spent catalyst.

In a preferred embodiment, the apparatus further comprises a regenerated catalyst stripper 50, and the regenerated catalyst stripper 50 is disposed on a pipeline connecting the regenerated catalyst outlet and the regenerated catalyst inlet to perform a stripping treatment on the regenerated catalyst. This enables the regenerated catalyst to be brought into contact with steam, and the catalytic effect of the regenerated catalyst can be further improved.

Preferably, as shown in fig. 1, there is one regenerated catalyst stripper 50, an inlet of the regenerated catalyst stripper 50 is communicated with a regenerated catalyst outlet, and outlets of the regenerated catalyst stripper 50 are respectively communicated with the regenerated catalyst inlets. Thus, in actual operation, the regenerated catalyst is treated by the same regenerated catalyst stripper 50 and then returned to each reactor 10 in several corresponding passes. This is beneficial to saving equipment and reducing cost.

Preferably, in an embodiment not shown in the drawings, the regenerated catalyst stripper 50 is at least two, the regenerated catalyst stripper 50 is disposed in one-to-one correspondence with the reactor 10, and the regenerated catalyst stripper 50 is disposed on a conduit where a regenerated catalyst inlet communicates with a regenerated catalyst outlet. Thus, in the actual operation process, the regenerated catalyst enters the corresponding regenerated catalyst stripper 50 for treatment in several ways and then enters the corresponding reactor 10, which is beneficial to improving the treatment effect of the regenerated catalyst.

In a preferred embodiment, the reactor 10 is internally provided with a primary cyclone and a secondary cyclone in series, the secondary cyclone being located downstream of the primary cyclone, and the gas phase outlet of the secondary cyclone being in communication with the product gas outlet. After the product gas generated by the reaction in the reactor 10 and the catalyst pass through the primary cyclone separator and the secondary cyclone separator, the product gas is discharged through a product gas outlet, and the catalyst to be generated is discharged from an outlet of the product gas outlet. The two stages of cyclone separators are arranged to separate the two more fully.

Preferably, the apparatus further comprises at least two tertiary cyclones, which are disposed in one-to-one correspondence with the quench water washing unit 30, and are disposed on the pipeline between the product gas outlet and the corresponding product gas inlet. The three-stage cyclone separator is arranged to further separate and remove the micro powder carried in the product gas.

In a preferred embodiment, the apparatus further comprises a first heat collector for recovering the heat of reaction inside the reactor 10. More preferably, the apparatus further comprises a second heat collector 60, the second heat collector 60 being used to recover the heat of the regeneration reaction inside the regenerator 20. Therefore, heat can be further recovered, and energy consumption is saved. The type of heat collector employed may be of the type commonly used in the art, preferably the first heat collector is an internal heat collector and/or an external heat collector; the second heat collector 60 is an internal heat collector and/or an external heat collector. That is, the first heat collector and the second heat collector may be a single inner heat collector or an outer heat collector, or may be a combination of the inner heat collector and the outer heat collector. More preferably, the second heat collector 60 is an external heat collector and the first heat collector is an internal heat collector.

Preferably, a feed distributor is arranged in the reactor 10, and the feed distributor is communicated with the methanol feed inlet. Preferably, the apparatus further comprises a methanol feed system in communication with the methanol feed inlet. Of course, a separate methanol feed system may be provided for each reactor 10, or one methanol feed system may be shared by each reactor 10. In addition, it is preferable that the apparatus further includes a fresh catalyst supply tank communicating with a fresh catalyst inlet of the reactor 10 and a spent catalyst recovery tank communicating with a spent catalyst outlet of the reactor 10 provided on a pipe between the spent catalyst inlet and the spent catalyst outlet.

Preferably, in an embodiment not shown in the figures, a reactor 10 and a regenerator 20 are arranged coaxially, and the regenerator 20 is arranged above the reactor 10. This allows gravity flow of the catalyst to be used to feed the regenerated catalyst separately into each reactor 10.

The specific operation of the above-described apparatus of the invention is illustrated by two reactors: after being preheated, the raw material methanol respectively enters two reactors 10 and contacts and reacts with the catalyst in the reactors 10. The product gas after reaction is separated from the catalyst by a three-stage cyclone separator, the catalyst generates coke after reaction, the activity is reduced, and the spent catalyst is formed. After being stripped, the spent catalysts in the two reactors 10 enter the same regenerator 20 through two paths respectively for regeneration (the spent catalyst inlets may be different inlets or the same inlet), the spent catalysts are in contact with oxygen in the air in the regenerator 20 for regeneration, coke on the catalysts is burned off, and the activity of the catalysts is recovered, so that the regenerated catalysts are obtained. The regenerated catalyst is led out from a regenerated catalyst outlet of the regenerator 20, and after independent steam stripping and cooling, the regenerated catalyst respectively enters the two reactors 10 for continuous reaction in two paths. In the process, the reaction regeneration system forms two paths of catalyst circulation, the circulation amount is respectively controlled, and a regenerator is shared. The product gases produced by the two reactors 10 enter different rapid cooling water washing devices after being heated.

In terms of process parameters, the temperature of the raw material methanol is raised to between 100 and 300 ℃ after heat exchange, the raw material methanol respectively enters two reactors through a feeding distributor to react, and the reaction temperature is between 400 and 550 ℃, preferably 400 and 500 ℃; the carbon deposit content of the spent catalyst is preferably 5-10 wt%, and more preferably controlled between 7-8 wt%. The reacted catalyst to be regenerated enters a regenerator for regeneration, and the regeneration temperature is between 600-780 ℃, preferably 650-700 ℃. The catalyst retention time in the regeneration reactor is controlled, an incomplete regeneration mode is adopted, the content of carbon in the regenerated catalyst is controlled to a certain degree, and the selectivity of the low-carbon olefin is improved. Preferably, the carbon content of the regenerated catalyst is controlled between 0.5 and 4.5 wt%, more preferably between 1 and 3 wt%.

According to another aspect of the present invention, there is also provided a methanol to olefin method, comprising the steps of: carrying out a methanol-to-olefin reaction in at least two reactors to obtain product gas and a spent catalyst; introducing the spent catalysts generated in the reactors into the same regenerator for catalyst regeneration to obtain regenerated catalysts; returning the regenerated catalyst to each reactor to continue the reaction of preparing olefin from methanol; and introducing the product gas generated in each reactor into a quenching water washing device which is arranged in one-to-one correspondence with the reactors to carry out quenching water washing treatment.

By utilizing the method for preparing olefin from methanol, the low generation rate of MTO reaction coke and the small load of regenerative coke burning are considered; the deactivation of the catalyst under the industrial condition is relatively slow, and the circulation quantity of the catalyst is low; the reaction product has the characteristics of small molecular weight, low pressure, contribution to improving the selectivity of low-carbon olefin, large load of a reactor and the like, two or more reactors share one regenerator for carrying out the reaction of preparing the olefin from the methanol, the capacity of a single device for preparing the olefin from the methanol can be greatly improved, and equipment and occupied area are saved.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

1. by adopting the technical scheme provided by the invention, the olefin productivity of a single set of methanol-to-olefin device reaches above megaton level, and compared with the maximum productivity of 68 ten thousand tons/year of a typical MTO technology in the prior art, the device productivity is improved by nearly 50 percent, and the device reaches the scale level of an ethylene device in petrochemical industry, and has obvious scale effect and economic benefit.

2. The invention adopts a plurality of reactors to share one regenerator, can save the investment of a regeneration system of a methanol-to-olefin device, saves corresponding equipment such as the regenerator, a main air compressor, a secondary cyclone separator of the regenerator, a tertiary cyclone separator of the regenerator and the like, and can reduce the investment by more than 15 percent in the unit olefin capacity.

3. The invention improves the productivity of the device, and saves the occupied area by more than 20 percent compared with the same-scale device.

4. The product gas outlets of the two reactors adopt independent quench water washing systems, and the two reaction regeneration systems have strong independence and more flexible operation.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing olefins from methanol is characterized by adopting a methanol-to-olefins device for preparation, and the methanol-to-olefins device comprises the following steps:

the device comprises at least two reactors (10), wherein each reactor (10) is provided with a spent catalyst outlet, a regenerated catalyst inlet and a product gas outlet;

the regenerator (20) is provided with a spent catalyst inlet and a regenerated catalyst outlet, the spent catalyst inlet is respectively communicated with each spent catalyst outlet, and the regenerated catalyst outlet is respectively communicated with each regenerated catalyst inlet; and

the reactor comprises at least two quenching water washing devices (30), wherein the quenching water washing devices (30) are arranged corresponding to the reactors (10) one by one, product gas inlets are formed in the quenching water washing devices (30), and the product gas inlets are communicated with the corresponding product gas outlets;

the device also comprises a regenerated catalyst stripper (50), wherein the regenerated catalyst stripper (50) is arranged on a pipeline for communicating the regenerated catalyst outlet with the regenerated catalyst inlet and is used for carrying out stripping treatment on the regenerated catalyst; the number of the regenerated catalyst stripper (50) is one, the inlet of the regenerated catalyst stripper (50) is communicated with the regenerated catalyst outlet, and the outlet of the regenerated catalyst stripper (50) is respectively communicated with the regenerated catalyst inlets; a primary cyclone separator and a secondary cyclone separator which are connected in series are arranged in the reactor (10), the secondary cyclone separator is positioned at the downstream of the primary cyclone separator, and a gas phase outlet of the secondary cyclone separator is communicated with the product gas outlet; the device also comprises at least two three-stage cyclone separators, the three-stage cyclone separators are arranged in one-to-one correspondence with the quenching water washing devices (30), and the three-stage cyclone separators are arranged on a pipeline between the product gas outlets and the corresponding product gas inlets;

the method comprises the following steps:

carrying out a methanol-to-olefin reaction in at least two reactors (10) to obtain a product gas and a spent catalyst;

introducing the spent catalyst generated in each reactor (10) into the same regenerator (20) for catalyst regeneration to obtain a regenerated catalyst;

returning the regenerated catalyst to each reactor (10) to continue the methanol-to-olefin reaction; and

introducing the product gas generated in each reactor (10) into the quenching water washing devices (30) which are arranged in one-to-one correspondence to the reactors (10) for quenching water washing treatment;

wherein the temperature of the methanol is raised to be between 100 and 300 ℃ after heat exchange, and the methanol respectively enters the two reactors (10) through the feeding distributor to react, and the reaction temperature is between 400 and 550 ℃; the carbon deposition content of the spent catalyst is 5-10 wt%; the reacted catalyst to be regenerated enters the regenerator (20) for regeneration, and the regeneration temperature is between 600 ℃ and 780 ℃; the carbon content of the regenerated catalyst is controlled between 0.5 and 4.5wt percent.

2. The method according to claim 1, characterized in that the device further comprises at least two spent catalyst strippers (40), the spent catalyst strippers (40) are arranged corresponding to the reactors (10) one by one, and the spent catalyst strippers (40) are arranged on a pipeline for communicating the spent catalyst inlet with the spent catalyst outlet.

3. The method according to claim 1 or 2, wherein the number of the regenerated catalyst strippers (50) is at least two, the regenerated catalyst strippers (50) are disposed in one-to-one correspondence with the reactors (10), and the regenerated catalyst strippers (50) are disposed on a pipe where the regenerated catalyst inlet communicates with the regenerated catalyst outlet.

4. A method according to claim 1 or 2, characterized in that the apparatus further comprises a first heat collector for recovering the heat of reaction inside the reactor (10).

5. The method according to claim 4, characterized in that the apparatus further comprises a second heat collector (60), the second heat collector (60) being used to recover the heat of the regeneration reaction inside the regenerator (20).

6. The method of claim 5, wherein the first heat collector is an internal heat collector and/or an external heat collector; the second heat collector (60) is an internal heat collector and/or an external heat collector.