CN114752400A

CN114752400A - Online switching device and method for fluidized bed catalyst for preparing low-carbon olefin from methanol

Info

Publication number: CN114752400A
Application number: CN202210351469.4A
Authority: CN
Inventors: 闫庆亮; 陈斌; 许锐; 陈海辉; 黄令漫; 胡斐; 王泽予; 王翔; 刘洪伟; 王志军; 尉雪峰
Original assignee: Guoneng Baotou Coal Chemical Co ltd; China Shenhua Coal to Liquid Chemical Co Ltd
Current assignee: Guoneng Baotou Coal Chemical Co ltd; China Shenhua Coal to Liquid Chemical Co Ltd
Priority date: 2022-04-02
Filing date: 2022-04-02
Publication date: 2022-07-15

Abstract

The invention relates to the technical field of catalyst replacement, and discloses an online switching device and method for a fluidized bed catalyst for preparing low-carbon olefin from methanol, which comprises the following steps: the reactor is communicated with a methanol feeding pipeline, the reactor is communicated with a regenerator provided with a catalyst to be replaced, the regenerator is provided with a catalyst unloading pipeline for unloading the catalyst and a catalyst adding pipeline for adding fresh replacement catalyst, and the catalyst adding pipeline is communicated with a carrier gas supply unit. The method adopts a multiple intermittent replacement mode to slowly replace a small amount of catalyst for a long period, gradually and completely switch the catalyst of the reactor and the regenerator without causing large-scale abrasion and loss of the catalyst, can effectively reduce the switching time of the fluidized bed catalyst, and does not influence the stable operation of an MTO device.

Description

Online switching device and method for fluidized bed catalyst for preparing low-carbon olefin from methanol

Technical Field

The invention relates to the technical field of catalyst replacement, in particular to an online switching device and method for a fluidized bed catalyst for preparing low-carbon olefin from methanol.

Background

The preparation of low-carbon olefin (MTO) from methanol refers to a chemical technology for generating low-carbon olefin by taking methanol as a raw material under the action of a catalyst at high temperature. At present, catalyst beds in the reverse reactor and the reverse reactor of an MTO device are generally fixed beds or fluidized beds, the online switching of catalysts is difficult in the actual production of fixed bed catalysts, the catalysts need to be replaced after the device is stopped when the catalysts are replaced, the pressure fluctuation of the reverse reactor and the reverse reactor exists when the fluidized bed catalysts are switched, a large amount of catalysts can be lost, and the catalysts in the fluidized beds can be abraded to generate a large amount of catalyst fine powder to deactivate and lose due to the difference of physicochemical properties of different catalysts, particularly the hardness of catalyst frameworks is different, so that the catalysts in the fluidized beds are abraded mutually.

In the coal chemical industry, especially the rapid development of low-carbon olefins made from coal, MTO catalysts of different manufacturers are produced at the same time, the MTO device has the situation of catalyst updating, and the on-line switching of the two fluidized bed catalysts is a difficult problem influencing the technical improvement of the MTO device. CN 106699931A discloses an on-line catalyst switching method for a gas-phase fluidized bed, which is applied to the technical field of ethylene polymerization. The catalyst is added to the reaction in small amounts to maintain the reaction at a lower loading, displacing the bed. The method is complex to operate, and normal production cannot be guaranteed by low-load operation. CN211612638U discloses an ethylene polymerization reaction device capable of switching different catalyst systems, and the method has the disadvantages of complex process, equipment and flow and high operation cost.

Disclosure of Invention

The invention aims to solve the problems that in the prior art, a large amount of catalyst is lost and stable operation of an MTO device is influenced due to switching of different types of catalysts for preparing low-carbon olefin from methanol, and provides an online switching device and method for a fluidized bed catalyst for preparing low-carbon olefin from methanol.

In order to achieve the above object, one aspect of the present invention provides an online switching device for a fluidized bed catalyst for producing low carbon olefins from methanol, comprising:

the reactor is communicated with a methanol feeding pipeline, the reactor is communicated with a regenerator provided with a catalyst to be replaced, the regenerator is provided with a catalyst unloading pipeline for unloading the catalyst, a catalyst adding pipeline for adding fresh replacement catalyst and a circulating agent pipeline for circulating the catalyst back to the reactor, and the catalyst adding pipeline is communicated with a carrier gas supply unit.

Preferably, the dosing line is in communication with a dosing tank containing fresh replacement catalyst, and the dosing tank is in communication with a fresh replacement catalyst feed line.

Preferably, the agent discharge line is in communication with an agent discharge tank, which is in communication with a negative pressure system for pumping catalyst from the regenerator to the agent discharge tank.

Preferably, the dosing tank is in communication with the negative pressure system for drawing fresh replacement catalyst into the dosing tank through a catalyst feed line;

the additive tank is communicated with the carrier gas supply unit through a pipeline provided with a control valve and is used for boosting the pressure of the additive tank so as to enable fresh replacement catalyst to enter the regenerator.

Preferably, a circulation port communicating with a circulation agent line for circulating the catalyst back to the reactor and a discharge port communicating with the discharge agent line are each provided at the bottom of the regenerator.

Preferably, the distance between the agent adding opening communicated with the agent adding pipeline and the agent discharging opening in the height direction is 1m-4m, and further preferably 1m-3 m.

Preferably, the negative pressure system is communicated with the carrier gas unit.

In another aspect of the present invention, an on-line switching method for a fluidized bed catalyst for preparing low carbon olefins from methanol is provided, and the method is performed in the apparatus of the present invention, and includes the following steps:

1) the fresh replacement catalyst is sent into the regenerator running on line through the additive pipeline along with the carrier gas and is mixed with the catalyst to be replaced contained in the regenerator to form a mixed catalyst;

2) feeding the mixed catalyst in the step 1) into the reactor through the circulating agent pipeline for reaction, and circulating the mixed catalyst to and from the regenerator and the reactor;

3) during the circulation process, sending part of the mixed catalyst out of the regenerator through the agent unloading pipeline;

4) and repeating the steps 1) -3) for multiple times until the catalyst to be replaced is switched by the fresh replacement catalyst.

Preferably, the method further comprises the negative pressure system pumping mixed catalyst from the regenerator to the unloading tank;

the negative pressure system draws fresh replacement catalyst from a fresh replacement catalyst feed line to the additive tank;

when the fresh replacement catalyst is fed into the regenerator, the carrier gas unit raises the pressure of the additive tank to 0.2-0.5 MPa, more preferably 0.35-0.4 MPa.

Preferably, the total amount of catalyst per addition of step 1) to the regenerator 2 is from 1 to 10t, more preferably from 3 to 7 t.

Preferably, the flow rate of the additive entering the regenerator in step 1) is between 0.2 and 2t/h, more preferably between 0.8 and 1.2 t/h.

Preferably, the time between the circulation of the mixed catalyst to and from the regenerator and the reactor in step 2) is between 0 and 48h, preferably between 6 and 12 h.

Preferably, the amount of mixed catalyst discharged in step 3) is from 1.67% to 16.67% by weight, preferably from 5% to 11.67% by weight, of the catalyst in the regenerator.

Preferably, the time for each discharge of mixed catalyst of step 3) is from 1 to 7 hours, preferably from 2.5 to 3.5 hours.

Preferably, the condition for completion of the handover in step 4): the ratio of the amount of fresh replacement catalyst to the total amount of catalyst in the reactor and in the regenerator is greater than 90 wt%.

Preferably, the total amount of catalyst in the reactor and in the regenerator is from 80t to 120t, more preferably from 95t to 105 t.

Preferably, the temperature of the catalyst flowing through the agent discharge line in step 3) is controlled to be in the range of 100 ℃ to 450 ℃, preferably 250 ℃ to 350 ℃.

According to the technical scheme, a small amount of catalyst is slowly replaced for a long period by adopting a multiple intermittent replacement mode, the catalysts of the reactor and the regenerator are gradually and completely switched, large-scale abrasion and loss of new catalyst and replaced catalyst are avoided, the total switching time of the fluidized bed catalyst can be effectively reduced, the stable operation of an MTO device is not influenced, the fresh replaced catalyst firstly enters the regenerator to be preheated and activated, the heat of the regenerator is effectively utilized, the heat load recombination of the replaced catalyst is not increased, the MTO reaction is facilitated, and the method fills the blank of the in-service device fluidized bed catalyst on-line switching technology in the production technology of low-carbon olefin from methanol.

Drawings

FIG. 1 is a schematic view of the flow structure of the on-line switching device for fluidized bed catalyst for producing low carbon olefins from methanol according to a preferred embodiment of the present invention.

Description of the reference numerals

1, a reactor; 2 a regenerator; 3 a discharge line; 4 an additive adding pipeline; 41 adding agent tank; 5 fresh replacement catalyst feed line; 31a discharge tank; 6 automatic feeder.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For numerical ranges, each range between its endpoints and individual point values, and each individual point value can be combined with each other to give one or more new numerical ranges, and such numerical ranges should be construed as specifically disclosed herein.

In the present invention, the use of directional terms such as "upper, lower, left, right" generally means upper, lower, left, right as viewed with reference to the accompanying drawings, unless otherwise specified; "inner and outer" refer to the inner and outer relative to the profile of the components themselves.

As shown in fig. 1, the present invention provides an online switching device for a catalyst in a fluidized bed for preparing low carbon olefins from methanol, comprising:

the reactor 1 is communicated with a methanol feeding pipeline, the reactor 1 is communicated with a regenerator 2 filled with a catalyst to be replaced, the regenerator 2 is provided with an unloading pipeline 3 for unloading the catalyst, an adding pipeline 4 for adding fresh replacement catalyst and a circulating agent pipeline for circulating the catalyst back to the reactor 1, and the adding pipeline 4 is communicated with a carrier gas supply unit.

The device can firstly add fresh replacement catalyst into the regenerator 2 to be mixed with the catalyst to be replaced in the regenerator to form mixed catalyst, the mixed catalyst enters the reactor 1 to participate in the reaction process of preparing low-carbon olefin from methanol, and after a period of reaction-regeneration circulation is carried out between the reactor and the regenerator, a part of the mixed catalyst is discharged through the agent discharging pipeline 3 (at the moment, in the mixed catalyst, the specific gravity of the catalyst to be replaced is greater than that of the fresh replacement catalyst, and most of the catalyst to be replaced can be discharged); then, adding fresh replacement catalyst through the additive pipeline, repeating the process, and slowly switching the catalyst to be replaced by the fresh replacement catalyst in a small quantity and multiple times manner, wherein the adding quantity of the fresh replacement catalyst is equal to or unequal to the discharging quantity of the mixed catalyst.

In addition, the fresh replacement catalyst firstly enters the regenerator to be preheated and activated, the heat of the regenerator is effectively utilized, the heat load recombination of the replacement catalyst cannot be increased, if the fresh replacement catalyst is added into the reactor, the cold fresh replacement catalyst directly causes the sudden drop of the MTO reaction temperature, the stability of a reaction system is influenced, and the fresh catalyst forms a certain amount of fixed carbon in the regenerator to be beneficial to the reaction (the fixed carbon is moderate, too much catalyst is inactivated, and the reaction is less);

the device can switch the catalyst without stopping, does not cause large-scale abrasion and loss of the catalyst, can effectively reduce the production cost of the low-carbon olefin prepared from methanol and the total switching time of the catalyst, and fills the technical blank of on-line switching of the fluidized bed catalyst of the on-line device in the production technology of the low-carbon olefin prepared from methanol.

In the invention, the additive pipeline 4 is communicated with an additive tank 41 filled with fresh replacement catalyst, and the additive tank 41 is communicated with a fresh replacement catalyst feeding pipeline 5.

In the present invention, the agent discharging pipeline 3 is communicated with an agent discharging tank 31, and the agent discharging tank 31 is communicated with a negative pressure system for pumping the catalyst from the regenerator 2 to the agent discharging tank 31. The adoption of the optimization has the advantages of stable reverse system, low operation cost, safety and practicability. In some embodiments of the invention, the negative pressure system is configured as a vapor pump in communication with the vapor line.

In the present invention, the additive tank 41 is communicated with the negative pressure system, and is used for pumping fresh replacement catalyst into the additive tank 41 through the catalyst feeding line 5;

the additive tank 41 communicates with the carrier gas supply unit through a pipe provided with a control valve for pressurizing the additive tank 41 to enable fresh replacement catalyst to enter the regenerator 2. Fresh replacement catalyst is pumped into the agent adding tank 41 through a catalyst feeding pipeline 5 by a negative pressure system by adopting a negative pressure method, then carrier gas is introduced to boost the pressure of the agent adding tank to be higher than the pressure in the regenerator 2, and the fresh replacement catalyst is fed into the regenerator by utilizing a positive pressure method.

According to a preferred embodiment of the present invention, a circulation port communicating with a circulating agent line for circulating the catalyst back to the reactor 1 and a discharge port communicating with the discharge line 3 are each provided at the bottom of the regenerator 2.

The agent discharging port is arranged at the bottom of the regenerator 2 to preferentially replace the catalyst to be replaced in the dead zone at the bottom, and the replaced catalyst to be replaced has larger deposition amount at the bottom in a period of operation due to different physical properties of the two catalysts.

According to a preferred embodiment of the present invention, the distance between the dosing port communicating with the dosing line 4 and the discharge port in the height direction is preferably 1m to 4m, more preferably 1m to 3 m.

The use of the foregoing preferences is effective in permitting fresh replacement catalyst to be added directly to the dense phase zone to facilitate catalyst incorporation and replacement.

In the invention, the negative pressure system is communicated with the carrier gas unit.

The invention provides an online switching method of a fluidized bed catalyst for preparing low-carbon olefin from methanol, which is carried out in the device provided by the invention and comprises the following steps:

1) the fresh replacement catalyst is sent into the regenerator 2 running on line through the additive pipeline 4 along with the carrier gas, and is mixed with the catalyst to be replaced in the regenerator to form a mixed catalyst;

2) feeding the mixed catalyst in the step 1) into the reactor 1 through the circulating agent pipeline for reaction, and circulating the mixed catalyst to and from the regenerator 2 and the reactor 1;

3) during the circulation, part of the mixed catalyst is sent out of the regenerator 2 through the agent unloading pipeline 3;

In the invention, fresh replacement catalyst is firstly added into a regenerator 2 and mixed with the catalyst to be replaced in the regenerator to form mixed catalyst, the mixed catalyst enters a reactor 1 to participate in the reaction process of preparing low-carbon olefin from methanol, and after a period of reaction-regeneration circulation is carried out between the reactor and the regenerator, the mixed catalyst is discharged out of a part through a discharging pipeline 3 (at the moment, in the mixed catalyst, the specific gravity of the catalyst to be replaced is greater than that of the fresh replacement catalyst, and most of the catalyst to be replaced can be discharged out); then, fresh replacement catalyst is added through the additive pipeline 4, the process is repeated, the catalyst to be replaced is slowly switched by the fresh replacement catalyst in a small quantity and a plurality of times, and the adding quantity of the fresh replacement catalyst is equal to or unequal to the discharging quantity of the mixed catalyst.

the invention adopts a multiple intermittent replacement mode to slowly replace a small amount of catalyst through a long period, gradually and completely switch the catalyst of the reactor and the regenerator without causing large-scale abrasion and loss of new catalyst and replaced catalyst, can effectively reduce the total switching time of the fluidized bed catalyst, and does not influence the stable operation of an MTO device.

In some embodiments of the present invention, after each step 1) -3) is performed, the next step 1) -3) is performed repeatedly at certain time intervals, that is, the switching process is performed periodically at time intervals of 3 days to 15 days, and optimally at time intervals of 6 days to 7 days, so that the mixing and replacement of the fresh replacement catalyst and the catalyst to be replaced can be facilitated.

In the present invention, the method further comprises the negative pressure system pumping mixed catalyst from the regenerator 2 to the unloading tank 31; the adoption of the optimization is favorable for the stability of the reverse system, and the operation cost is low, safe and practical.

The negative pressure system draws fresh replacement catalyst from the fresh replacement catalyst feed line 5 to the additive tank 41;

when the fresh replacement catalyst is fed into the regenerator 2, the carrier gas unit raises the pressure of the additive tank 41 to 0.2MPa to 0.5MPa, preferably 0.35MPa to 0.4 MPa.

The catalyst tank has the advantages that in the process of adding the catalyst, the pressure difference is favorable for adding the catalyst by a positive pressure method, and along with the implementation of the catalyst, the pressure drop of the catalyst tank is small, so that the catalyst adding system is not influenced.

According to a preferred embodiment of the invention, the total amount of catalyst per addition of step 1) to the regenerator 2 is from 1 to 10t, preferably from 3 to 7 t. The use of the above preference has the advantage of optimum displacement, low influence on the operation of the production plant and low influence on the activity of the catalyst.

According to a preferred embodiment of the invention, the dosing flow into the regenerator 2 in step 1) is between 0.2 and 2t/h, preferably between 0.8 and 1.2 t/h. The adoption of the optimization has low influence on the operation of a production device, and the low influence on the activity of the catalyst is beneficial to the mixing and replacement of the catalyst of the reverse recycling system.

According to a preferred embodiment of the present invention, the time between the circulation of the mixed catalyst in step 2) to and from the regenerator 2 and the reactor 1 is between 0 and 48 hours, preferably between 6 and 12 hours. This can facilitate the blending and replacement of fresh replacement catalyst and catalyst to be replaced.

According to a preferred embodiment of the invention, the amount of mixed catalyst per discharge of step 3) is between 1.67% and 16.67% by weight, preferably between 5% and 11.67% by weight, of catalyst in the regenerator. The catalyst to be replaced is slowly switched by the fresh replacement catalyst in a small quantity and multiple times mode, so that large-scale abrasion and running loss of the catalyst can be avoided, and the influence on the operation of a production device is low.

According to a preferred embodiment of the invention, the time per discharge of mixed catalyst in step 3) is from 1 to 7 hours, preferably from 2.5 to 3.5 hours. The method can protect the discharging agent pipeline and the discharging agent tank from being damaged due to overhigh temperature of the discharged catalyst while ensuring the replacement efficiency.

According to a preferred embodiment of the invention, the temperature of the catalyst flowing through the agent discharge line 3 in step 4) is controlled to be between 100 ℃ and 450 ℃, preferably between 250 ℃ and 350 ℃. It should be noted that, when discharging the agent, the temperature needs to be controlled by controlling the flow rate of the discharging agent to avoid damaging the discharging agent pipeline, for example, by controlling the opening degree of a valve arranged on the discharging agent pipeline.

According to a preferred embodiment of the present invention, the condition for completion of the handover in step 3): the amount of fresh replacement catalyst is greater than 90 wt% of the total amount of catalyst in the reactor 1 and the regenerator 2.

According to a preferred embodiment of the invention, the total amount of catalyst in the reactor 1 and in the regenerator 2 is between 80t and 120t, preferably between 95t and 105 t.

In the invention, the carrier gas is inert gas (such as nitrogen) and/or steam generated in the process of preparing the low-carbon olefin from the methanol.

In some embodiments of the invention, the apparatus comprises a control unit for controlling automatic switching of the catalyst, the control unit comprising:

an auto-feeder 6 for automatically feeding fresh replacement catalyst of a dosing tank 41 into the regenerator 2;

the discharge hole of the automatic feeder 6 is communicated with the regenerator 2, the feed hole of the automatic feeder 6 is communicated with the additive tank 41, and the automatic feeder 6 is communicated with the carrier gas supply unit;

it can be understood that the control unit adopts the plc controller control, and the valve on the material passageway can set up to the solenoid valve, and every solenoid valve and automatic material feeder are connected to the plc controller electricity, and the plc controller can set up corresponding procedure to accurate control dosing and dosing cycle, the material cost of using manpower sparingly.

In the invention, the discharge hole of the automatic feeder 6 is communicated with the feeding pipeline 4.

In the present invention, the control system includes a control device in which a control program is installed, and the control device is electrically connected to the automatic feeder 6, the regenerator 2, and the carrier gas unit.

It should be noted that, the present invention can add common parts such as control valves, pipes, meters, etc. according to the need, and electronic devices such as control valves or meters, etc. can be electrically connected to the plc control device according to the need, which is not described in detail herein.

In the invention, the catalyst to be replaced and the fresh replacement catalyst are referred to as substitutes, and mainly refer to replacement regeneration in the regeneration process, for example, the catalyst to be replaced and the fresh replacement catalyst are the same catalyst to be regenerated, for example, the catalyst to be replaced and the fresh replacement catalyst are UOP-MTO catalyst or midkine MTO catalyst, or different types of catalysts to be regenerated, for example, the catalyst to be replaced and the fresh replacement catalyst are midkine MTO catalyst, UOP-MTO catalyst, Shandong Jiangyueyue MTO catalyst, Zhengda MTO catalyst, Shenhua first-generation or second-generation MTO catalyst.

It should be noted that the MTO catalyst uses SAPO-34 as a template, and the basic structure is uniform.

The invention is further illustrated by the following examples and comparative examples, without being limited thereto.

The following examples were carried out in an on-line shift apparatus for a fluidized bed catalyst for producing lower olefins from methanol as shown in FIG. 1, which apparatus comprises:

the reactor 1 is communicated with a methanol feeding pipeline, the reactor is communicated with a regenerator 2 filled with a UOP-MTO catalyst (a catalyst which is purchased from a UOP plant and takes SAPO-34 as a template), the regenerator is provided with an unloading pipeline 3, an adding pipeline 4 and a circulating agent pipeline, the adding pipeline is communicated with a carrier gas supply unit and an adding tank 41 filled with a midget MTO catalyst (a catalyst which is purchased from a midget plant and takes SAPO-34 as a template), the adding tank is communicated with a fresh replacement catalyst feeding pipeline 5, a negative pressure system and a carrier gas supply unit, the unloading pipeline 3 is communicated with an unloading tank 31, the unloading tank 31 is communicated with a negative pressure system, and the negative pressure system is communicated with the carrier gas unit;

the on-line switching method of the fluidized bed catalyst for preparing the low carbon olefin from the methanol comprises the following steps:

1) the intermediate MTO catalyst is sent into the regenerator 2 which runs on line through the additive pipeline 4 along with nitrogen, and is mixed with the UOP-MTO catalyst filled in the regenerator to form a mixed catalyst;

2) circulating the mixed catalyst in step 1) to and from the regenerator 2 and the reactor 1 through the circulating agent line;

4) repeating the above steps 1) -3) for a plurality of times until the intermediate MTO catalyst completes the switching of the UOP-MTO catalyst.

Example 1

The distance between a dosing port and a discharging port is 1m, a carrier gas unit boosts the pressure of a dosing tank 41 to 0.38MPa, the total amount of the Chinese MTO catalyst added into the regenerator 2 in each step 1) is 4t, the dosing flow is 0.6t/h, the time of the mixed catalyst circulating to and from the regenerator 2 and the reactor 1 in the step 2) is 7h, the amount of the mixed catalyst discharged in the step 3) is 3 wt% of the catalyst in the regenerator 2, the time of the mixed catalyst discharged in the step 3) is 7h, the total amount of the catalyst in the reactor 1 and the regenerator 2 is 100t, and the temperature of the catalyst flowing through a discharging pipeline 3 is 100 ℃; the loss rate of the intermediate MTO catalyst was 9.4%.

Example 2

The distance between the agent adding port and the agent discharging port is 3m, the pressure of the agent adding tank 41 is increased to 0.2MPa by a carrier gas unit, the total amount of the Chinese MTO catalyst added into the regenerator 2 in each step is 8t, the agent adding flow is 0.2t/h, the time of the mixed catalyst circulating to and from the regenerator 2 and the reactor 1 in the step 2) is 24h, the amount of the mixed catalyst discharged in the step 3) is 15 wt% of the catalyst in the regenerator 2, the time of the mixed catalyst discharged in the step 3) is 2h, the total amount of the catalyst in the reactor 1 and the regenerator 2 is 80t, and the temperature of the catalyst flowing through the agent discharging pipeline 3 is 300 ℃; the loss rate of the intermediate MTO catalyst was 15.2%.

Example 3

The distance between a dosing port and a dosing port is 2m, a carrier gas unit boosts the pressure of a dosing tank 41 to 0.5MPa, the total amount of the Chinese MTO catalyst added into the regenerator 2 every time in the step 1) is 2t, the dosing flow rate is 2t/h, the time of circulating the mixed catalyst to and fro between the regenerator 2 and the reactor 1 in the step 2) is 48h, the amount of the mixed catalyst discharged in the step 3) every time is 15 wt% of the catalyst in the regenerator 2, the time of discharging the mixed catalyst in the step 3) every time is 2h, the total amount of the catalyst in the reactor 1 and the regenerator 2 is 120t, and the temperature of the catalyst flowing through a dosing pipeline 3 is 450 ℃; the loss rate of the intermediate MTO catalyst was 13.1%.

Example 4

The difference from example 1 is: step 1) the total amount of the intermediate MTO catalyst added into the regenerator 2 each time is 5 t; the loss rate of the intermediate MTO catalyst was 3.4%.

Example 5

The difference from example 1 is: the adding agent flow is 1.2 t/h; the loss rate of the intermediate MTO catalyst was 4.2%.

Comparative example 1

Dividing the total reserve of 100t into 4 times of replacement by adopting the equipment in the prior art, wherein 25t of the intermediate MTO catalyst is added into a regenerator at first, then 25tUOP-MTO catalyst is discharged, the total reserve is controlled to be 100t, the operation is carried out for 2 days, and then the replacement is repeated for 4 times; the loss rate of the intermediate MTO catalyst is about 50%, and there is a great deal of catalyst attrition to become small particles that run off to the next system.

The comparison shows that the loss rate of the fresh replacement catalyst can be effectively reduced to 3.4%, the unit consumption of the catalyst for preparing the olefin from the methanol is effectively reduced, the operation cost of the device is directly reduced, and the invention fills the blank of the technology for on-line switching of the fluidized bed catalyst of the on-line device in the production technology of preparing the low-carbon olefin from the methanol.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, numerous simple modifications can be made to the technical solution of the invention, including combinations of the specific features in any suitable way, and the invention will not be further described in relation to the various possible combinations in order to avoid unnecessary repetition. Such simple modifications and combinations should also be considered as disclosed in the present invention, and all such modifications and combinations are intended to be included within the scope of the present invention.

Claims

1. The utility model provides a low carbon olefin fluidized bed catalyst online switching device is prepared to methyl alcohol which characterized in that, the device includes:

the reactor (1) is communicated with a methanol feeding pipeline, the reactor (1) is communicated with a regenerator (2) filled with a catalyst to be replaced, the regenerator (2) is provided with a catalyst unloading pipeline (3), a catalyst adding pipeline (4) and a circulating agent pipeline, the catalyst unloading pipeline is used for unloading the catalyst, the fresh catalyst replacing pipeline is used for adding fresh catalyst, the circulating agent pipeline is used for circulating the catalyst to return to the reactor (1), and the catalyst adding pipeline (4) is communicated with a carrier gas supply unit.

2. The apparatus according to claim 1, wherein the dosing line (4) is in communication with a dosing tank (41) containing fresh replacement catalyst, the dosing tank (41) being in communication with a fresh replacement catalyst feed line (5);

and/or

The agent discharging pipeline (3) is communicated with an agent discharging tank (31), and the agent discharging tank (31) is communicated with a negative pressure system for sucking the catalyst from the regenerator (2) to the agent discharging tank (31).

3. The apparatus of claim 2, wherein the dosing tank (41) is in communication with the negative pressure system for drawing fresh replacement catalyst into the dosing tank (41) through a catalyst feed line (5);

the additive tank (41) is communicated with the carrier gas supply unit through a pipeline provided with a control valve and is used for pressurizing the additive tank (41) so as to enable fresh replacement catalyst to enter the regenerator (2).

4. The apparatus of claim 2 or 3,

a circulating port communicated with a circulating agent pipeline for circulating the catalyst back to the reactor (1) and a discharging port communicated with the discharging agent pipeline (3) are respectively arranged at the bottom of the regenerator (2);

preferably, the distance between the agent adding port communicated with the agent adding pipeline (4) and the agent discharging port in the height direction is 1m-4m, and more preferably 1m-3 m.

5. The device of any one of claims 2-4, wherein the negative pressure system is in communication with the carrier gas cell.

6. An on-line switching method for a fluidized bed catalyst for preparing low carbon olefin from methanol, which is carried out in the device of any one of claims 1 to 5, and comprises the following steps:

1) the fresh replacement catalyst is sent into the regenerator (2) running on line through the additive pipeline (4) along with the carrier gas, and is mixed with the catalyst to be replaced in the regenerator to form a mixed catalyst;

2) circulating the mixed catalyst in step 1) to and from the regenerator (2) and the reactor (1) through the circulating agent line;

3) during the circulation, part of the mixed catalyst is sent out of the regenerator (2) through the agent unloading pipeline (3);

7. The method of claim 6, further comprising the negative pressure system pumping mixed catalyst from the regenerator (2) to the unloading tank (31);

the negative pressure system draws fresh replacement catalyst from a fresh replacement catalyst feed line (5) to the dosing tank (41);

when the fresh replacement catalyst is fed to the regenerator (2), the carrier gas unit raises the pressure of the additive tank (41) to 0.2MPa to 0.5MPa, preferably 0.35MPa to 0.4 MPa.

8. The process according to claim 6 or 7, wherein the total amount of catalyst per addition of step 1) to the regenerator (2) is from 1 to 10t, preferably from 3 to 7 t;

the dosage flow is further preferably 0.2 to 2t/h, and the dosage flow is further preferably 0.8 to 1.2 t/h;

and/or

The time for circulating the mixed catalyst to and from the regenerator (2) and the reactor (1) in the step 2) is 0 to 48 hours, preferably 6 to 12 hours.

9. The method according to any one of claims 6 to 8,

the amount of the mixed catalyst discharged in each time in the step 3) is 1.67-16.67 wt% of the catalyst in the regenerator, and preferably 5-11.67 wt%;

and/or

The time of discharging the mixed catalyst in step 3) is 1-7h, preferably 2.5-3.5 h;

and/or

The condition for completing the switching in the step 4): the content of fresh replacement catalyst is greater than 90 wt% of the total amount of catalyst in the reactor (1) and in the regenerator (2).

10. The process according to any one of claims 6 to 9, wherein the total amount of catalyst in the reactor (1) and in the regenerator (2) is between 80t and 120t, preferably between 95t and 105 t;

and/or

The temperature of the catalyst flowing through the agent discharge line (3) in step 3) is controlled to be 100 ℃ to 450 ℃, preferably 250 ℃ to 350 ℃.