Method for preparing isobutene by decomposing MTBE (Methyl Tert-Butyl Ether)
By using methylcyclohexanone, phenol or mixtures thereof as regulators in the MTBE decomposition reaction, the problem of high linear butene content in isobutene products was solved, and the preparation of high purity isobutene was achieved.
Patent Information
- Application Number
- CN202311436617.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-31
- Publication Date
- 2025-05-02
AI Technical Summary
The prior art is difficult to effectively reduce the content of linear butene in isobutene products, resulting in a decrease in the purity of diisobutene.
In the MTBE decomposition reaction, methyl cyclohexanone, phenol or a mixture thereof are added as regulators to adjust the MTBE decomposition reaction and the side reaction of MSBE decomposition, and reduce the formation of linear butene.
Through this method, the content of 1-butene and 2-butene in isobutene products is greatly reduced, and the purity of isobutene can reach more than 99.95%.
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Figure CN119912305A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of isobutylene preparation, and specifically relates to a method for preparing isobutylene by decomposing methyl tert-butyl ether (MT BE), and is particularly suitable for preparing high-purity isobutylene. Background Art
[0002] Isobutylene is an important organic chemical raw material, which can be used to synthesize a variety of products, such as intermediates and additives for the production of medicines and pesticides, and can also be used in the production of methyl methacrylate, butyl rubber and polyisobutylene. When isobutylene is used as a raw material to produce diisobutylene as a chemical raw material, the less linear butene (1-butene and 2-butene) in isobutylene, the better, because the presence of linear butene will reduce the purity of diisobutylene.
[0003] The decomposition of methyl tert-butyl ether (MTBE) is one of the main technologies for producing high-purity isobutylene and is also the most widely used technical route. The main reaction of MTBE decomposition is that MTBE decomposes into isobutylene and methanol, while the side reaction of methyl sec-butyl ether (MSBE) decomposing into linear butene and methanol occurs at the same time. The linear butene generated by the side reaction is difficult to separate from isobutylene by distillation.
[0004] The existing method of reducing linear butene in isobutylene products is mainly to reduce the content of MSBE in the raw materials entering the reactor. One way is to impose strict requirements on the upstream device that provides MTBE raw materials, which increases the production difficulty and cost of the upstream device. Another way is to separate MSBE from the MTBE raw material by distillation, but since MSBE and MTBE are isomers with similar boiling points, the number of theoretical plates required for distillation is too large, the investment is too large, and the energy consumption is also high. For example, patent CN 101134705 of Evonik Oxenauer of Germany discloses a method for preparing isobutylene by gas phase decomposition of MTBE, which requires that the MSBE content in the MTBE raw material entering the reactor is less than 2500 mass ppm. If MSBE is to be separated in the raw material refining tower, the number of theoretical plates required for the MTBE refining tower is 95, and the reflux ratio is 3.7.
[0005] The prior art does not yet have a method for reducing linear butene in isobutylene products through a reaction process. Summary of the invention
[0006] In order to solve the above problems existing in the prior art, the present invention provides a method for preparing isobutylene by decomposing MTBE. The MTBE raw material is decomposed in the presence of a regulator, so that the MTBE reaction conversion rate is high, the MSBE reaction conversion rate is low, and the linear butene content in the isobutylene product is greatly reduced.
[0007] In order to achieve the above object, the present invention adopts the following technical scheme:
[0008] A method for preparing isobutylene by decomposing MTBE comprises the following steps:
[0009] The MTBE raw material undergoes a decomposition reaction in the presence of a catalyst and a regulator, and the decomposition reaction product is separated to obtain an isobutylene product;
[0010] The regulator is one of methylcyclohexanone and phenol or a mixture of the two, and the mass ratio of the regulator to the MTBE raw material is 0.001-0.05:1.
[0011] Preferably, the MTBE raw material contains 1% to 99.9999% MTBE and 0.0001% to 3% MSBE by mass, and the total mass fraction of MTBE and MSBE is less than or equal to 100%; more preferably, the MTBE raw material contains 90% to 99.999% MTBE and 0.001% to 1% MSBE by mass, and the total mass fraction of MTBE and MSBE is less than or equal to 100%; particularly preferably, the MTBE raw material contains 98% to 99.9% MTBE and 0.1% to 0.5% MSBE by mass, and the total mass fraction of MTBE and MSBE is less than or equal to 100%.
[0012] Preferably, the MTBE raw material is subjected to removal of light components and heavy impurities before the decomposition reaction, preferably by using one or more distillation towers to remove the light components and heavy impurities.
[0013] Preferably, the mass ratio of the regulator to the MTBE raw material is 0.005-0.03:1.
[0014] Preferably, the regulator is a mixture of phenol and methylcyclohexanone in a mass ratio of 0.05 to 0.5:1; more preferably, the regulator is a mixture of phenol and methylcyclohexanone in a mass ratio of 0.1 to 0.3:1.
[0015] Preferably, the decomposition reaction product is separated by distillation to recover the regulator, and the recovered regulator is recycled.
[0016] Preferably, the catalyst is silica gel, cation exchange resin, supported inorganic acid salt, solid phosphoric acid catalyst or acidic molecular sieve; more preferably, the catalyst consists of a carrier and an active component supported on the carrier, the carrier is silicon dioxide, and the active component is a heteropolyacid or a mixture of a heteropolyacid and a metal salt.
[0017] Preferably, the volume space velocity of the catalyst is 0.01h -1 ~15h -1 , more preferably 0.1h -1 ~5h-1 .
[0018] Preferably, the reaction temperature of the decomposition reaction is 100°C to 350°C, and the reaction pressure is 0.1MPa to 4.0MPa; more preferably, the temperature of the decomposition reaction is 160 to 250°C, and the reaction pressure is 0.1 to 2.0MPa.
[0019] Preferably, the decomposition reaction is carried out in a reactor;
[0020] More preferably, the regulator and the MTBE raw material are mixed uniformly in a mixer and then enter the reactor filled with the catalyst; particularly preferably, the regulator and the MTBE raw material are mixed uniformly in a mixer and then preheated to 100-350° C. before entering the reactor; most preferably, the reactor feed and discharge are heat exchanged;
[0021] More preferably, the reactor is a shell-and-tube reactor, the catalyst is loaded in the tube side, and the heating medium is introduced into the shell side; especially preferably, the heating medium is heat transfer oil or steam.
[0022] Preferably, the method for preparing isobutylene by decomposing MTBE is one of method A and method B:
[0023] Method A: MTBE raw material is mixed with a regulator and then enters a reactor filled with a catalyst, the decomposition reaction product at the outlet of the reactor enters an isobutylene deweighting tower for distillation and separation, the bottom material of the isobutylene deweighting tower is sent to a regulator recovery tower for distillation, methanol is obtained at the top of the regulator recovery tower, and the regulator is obtained at the bottom of the tower, which is returned to the reactor for recycling; the top material of the isobutylene deweighting tower enters a methanol washing tower for washing, and methanol-free isobutylene, i.e., isobutylene product, is obtained at the top of the methanol washing tower; the bottom material of the methanol washing tower is sent to a methanol recovery tower, and the top material of the methanol recovery tower is methanol, which is used as a methanol by-product together with the methanol obtained at the top of the regulator recovery tower, and the bottom material is water, which is returned to the methanol washing tower as washing water for recycling;
[0024] Method B: MTBE raw material is mixed with a regulator and then enters a reactor filled with a catalyst, the decomposition reaction product at the outlet of the reactor first enters a methanol water washing tower, the bottom material is sent to a methanol recovery tower, the top material of the methanol recovery tower is sent to a regulator recovery tower for rectification, methanol by-product is obtained at the top of the tower, and the regulator is obtained at the bottom of the tower, which is returned to the reactor for recycling; the bottom discharge of the methanol recovery tower is water, which is returned to the methanol water washing tower for recycling as washing water; the isobutylene obtained at the top of the methanol water washing tower is passed through an isobutylene deweighting tower to remove the heavy components to obtain an isobutylene product;
[0025] More preferably, in the method A, the decomposition reaction product at the outlet of the reactor first enters a vapor-liquid separation tank for vapor-liquid flash separation, and then the gas phase at the top of the vapor-liquid separation tank is compressed by a compressor and sent to the isobutylene deweighting tower, and the bottom liquid phase is pumped into the isobutylene deweighting tower.
[0026] More preferably, in method A, isobutylene without methanol is transported to an isobutylene light component removal tower to remove light components, and an isobutylene product is obtained at the bottom of the tower.
[0027] More preferably, in the method B, the isobutylene obtained from the top of the methanol water washing tower is first passed through an isobutylene light-removing tower to remove the light components, and the bottom material is then passed through an isobutylene heavy-removing tower to remove the heavy components to obtain an isobutylene product.
[0028] More preferably, in the method A and the method B, the pressure of the isobutylene deweighting tower is 0.4-1.0 MPa, and the reflux ratio is 0.3-10, respectively.
[0029] More preferably, in the method A and the method B, the top pressure of the regulator recovery tower is 0.1-1.5 MPa, and the reflux ratio is 0.1-20, respectively. Especially preferably, the top pressure is 0.1-0.8 MPa, and the reflux ratio is 0.2-8, respectively.
[0030] More preferably, in the method A and the method B, the operating temperature of the methanol water washing tower is 25-60° C., and the pressure is 0.4-1.0 MPa.
[0031] More preferably, in the method A and the method B, the top pressure of the methanol recovery tower is 0.1-0.4 MPa, and the reflux ratio is 1-20.
[0032] More preferably, in the method A and the method B, the top pressure of the isobutylene light removal tower is 0.1-2.0 MPa, and the reflux ratio is less than 300.
[0033] Compared with the prior art, the present invention has the following advantages:
[0034] The method for preparing isobutylene by decomposing MTBE of the present invention effectively regulates the MTBE decomposition reaction and the MSBE decomposition side reaction by adding a regulator during the MTBE decomposition reaction process, and while maintaining a high MTBE conversion rate, the MSBE reaction conversion rate is greatly reduced, and the generated linear butene is greatly reduced. Experiments have shown that the content of 1-butene and 2-butene in the isobutylene product obtained after separation and purification of the decomposition reaction product is greatly reduced, and the purity of the isobutylene can reach more than 99.95%.
[0035] In addition, in the method for preparing isobutylene by decomposing MTBE of the present invention, the added regulator does not participate in the reaction during the reaction and is easy to recover. It can be recycled after being separated and recovered. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0037] Figure 1 The process flow diagram of the method for preparing isobutylene by decomposing MTBE in Examples 1 to 10 of the present invention is shown;
[0038] In the figure: 1. Reactor; 2. Isobutylene heavy removal tower; 3. Methanol water washing tower; 4. Methanol recovery tower; 5. Isobutylene light removal tower; 6. Regulator recovery tower; DETAILED DESCRIPTION
[0039] In order to further understand the present invention, preferred embodiments of the present invention are described below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.
[0040] The method for preparing isobutylene by decomposing MTBE of the present invention is based on the method for preparing isobutylene by decomposing an existing MTBE raw material in the presence of a catalyst. Because the existing MTBE raw material usually contains a certain amount of MSBE, when MTBE is decomposed into isobutylene and methanol under the action of the catalyst, MSBE decomposes to produce a side reaction to produce linear butene and methanol. The inventors found that when methylcyclohexanone, phenol or a mixture thereof is added to the decomposition reaction system, the MSBE reaction conversion rate is greatly reduced while maintaining a high MTBE conversion rate, and the generated linear butene is greatly reduced. Therefore, the present invention adds a regulator (methylcyclohexanone, phenol or a mixture thereof) in the process of preparing isobutylene by decomposing an MTBE raw material in the presence of a catalyst.
[0041] In the above technical scheme, the MTBE raw material can be any MTBE-containing material from any industrial source, can be MTBE obtained by chemical reaction, such as MTBE material synthesized by reacting isobutylene and methanol in mixed C4, can be purchased MTBE-containing material, can be a single source of MTBE-containing material, or can be two or more MTBE-containing materials from different sources. The MTBE raw material contains MTBE and MSBE, and may also contain methanol, tert-butyl alcohol, diisobutylene and C5 components, etc.; preferably, the MTBE raw material contains 1% to 99.9999% MTBE by mass and 0.0001% to 3% MSBE by mass, and the total mass fraction of MTBE and MSBE is less than or equal to 100%; more preferably, the MTBE raw material contains 90% to 99.999% MTBE by mass and 0.001% to 1% MSBE by mass, and the total mass fraction of MTBE and MSBE is less than or equal to 100%; especially preferably, the MTBE raw material contains 98% to 99.9% MTBE by mass and 0.1% to 0.5% MSBE by mass, and the total mass fraction of MTBE and MSBE is less than or equal to 100%. It is also preferred that the MTBE raw material is purified to remove light and heavy impurities before the decomposition reaction, and one or more distillation towers may be used to remove light and heavy impurities.
[0042] In the above technical scheme, the regulator is a mixture of one or both of methylcyclohexanone and phenol, and the mass ratio of the regulator to the MTBE raw material is 0.001-0.05:1; preferably, the mass ratio of the regulator to the MTBE raw material is 0.005-0.03:1. The inventors found that the effect is more ideal when phenol and methylcyclohexanone are added in a certain mass ratio. The preferred regulator is a mixture of phenol and methylcyclohexanone in a mass ratio of 0.05-0.5:1; more preferably, the regulator is a mixture of phenol and methylcyclohexanone in a mass ratio of 0.1-0.3:1. The regulator with the preferred ratio can more effectively regulate the MTBE decomposition reaction and the MSBE decomposition side reaction, so that the linear butene content in the isobutylene product is less.
[0043] In the above technical scheme, the catalyst can be any existing MTBE cracking catalyst, generally silica gel, cation exchange resin, supported inorganic acid salt, solid phosphoric acid catalyst or acidic molecular sieve, etc. The preferred catalyst is a catalyst with silicon dioxide as a carrier and an active component of a heteropoly acid or a mixture of a heteropoly acid and a metal salt. The catalyst volume space velocity is preferably 0.01h -1 ~15h -1 , more preferably 0.1h -1 ~5h -1 .
[0044] In the above technical solution, the reaction temperature of the decomposition reaction is 100°C to 350°C, and the reaction pressure is 0.1MPa to 4.0MPa; preferably, the temperature of the MTBE decomposition reaction is 160 to 250°C, and the reaction pressure is 0.1 to 2.0MPa.
[0045] In the above technical solution, the decomposition reaction is preferably carried out in a reactor; the regulator is preferably combined with the MTBE raw material into a stream before entering the reactor and mixed evenly in a mixer before entering the reactor; more preferably, the mixed material is preheated to 100-350°C before entering the reactor. Heat exchange is preferably performed between the reactor feed and discharge to reduce energy consumption.
[0046] In the above technical solution, the decomposition reaction of MTBE is an endothermic reaction, and the reactor is preferably a shell-and-tube reactor, the catalyst is loaded in the tube side, and the heating medium is introduced into the shell side, and the heating medium is preferably heat transfer oil or steam.
[0047] In the above technical solution, the decomposition reaction products at the reactor outlet are separated to obtain isobutylene product, methanol by-product and regulator, and the regulator is returned to the reaction part for recycling.
[0048] In the above technical solution, the method for preparing isobutylene by decomposing MTBE is one of method A and method B:
[0049] Method A: MTBE raw material is mixed with a regulator and then enters a reactor filled with a catalyst. The decomposition reaction product at the outlet of the reactor enters a vapor-liquid separation tank for vapor-liquid flash separation. The gas phase at the top of the vapor-liquid separation tank is compressed by a compressor and sent to an isobutylene deweighting tower. The liquid phase at the bottom is pumped into the isobutylene deweighting tower. The decomposition reaction product is rectified and separated in the isobutylene deweighting tower. The bottom product is mainly methanol and contains a regulator. The material at the bottom of the isobutylene deweighting tower is sent to a regulator recovery tower for distillation to recover the regulator. The methanol obtained at the top of the regulator recovery tower and the regulator at the bottom of the regulator recovery tower are obtained. , returned to the reactor for recycling; the top material of the isobutylene de-heavy tower enters the methanol water washing tower, the top of the methanol water washing tower obtains isobutylene without methanol, and the bottom material is sent to the methanol recovery tower; the top material of the methanol recovery tower is methanol, which is used as a methanol by-product together with the methanol obtained from the top of the regulator recovery tower, and can be used as a raw material for the MTBE synthesis unit. The bottom discharge is water, which returns to the methanol water washing tower as washing water for recycling; the methanol-free isobutylene obtained from the top of the methanol water washing tower can be selected to add an isobutylene light removal tower to remove the light components to obtain an isobutylene product (high purity). Among them, the isobutylene de-heavy tower preferably has a pressure of 0.4-1.0MPa and a reflux ratio of 0.3-10. The regulator recovery tower preferably has a top pressure of 0.1-1.5MPa and a reflux ratio of 0.1-20, and more preferably a top pressure of 0.1-0.8MPa and a reflux ratio of 0.2-8. The preferred operating temperature of the methanol water washing tower is 25-60°C and the pressure is 0.4-1.0 MPa. The preferred top pressure of the methanol recovery tower is 0.1-0.4 MPa and the reflux ratio is 1-20. The preferred top pressure of the isobutylene light removal tower is 0.1-2.0 MPa and the reflux ratio is less than 300.
[0050] Method B: After the MTBE raw material is mixed with the regulator, it enters a reactor filled with a catalyst. The decomposition reaction product at the outlet of the reactor first enters a methanol water washing tower, and the bottom material is sent to a methanol recovery tower. The top material of the methanol recovery tower is sent to a regulator recovery tower for distillation to recover the regulator. A methanol byproduct is obtained at the top of the tower, and a regulator is obtained at the bottom of the tower, which is returned to the reactor for recycling; the bottom discharge of the methanol recovery tower is water, which is returned to the methanol water washing tower as washing water for recycling; the isobutylene obtained at the top of the methanol water washing tower can be selected to add an isobutylene light removal tower to remove the light component, and the isobutylene at the bottom of the tower is then removed by an isobutylene heavy removal tower to remove the heavy component to obtain an isobutylene product (high purity). Among them, the isobutylene heavy removal tower preferably has a pressure of 0.4-1.0 MPa and a reflux ratio of 0.3-10. The regulator recovery tower preferably has a top pressure of 0.1-1.5 MPa and a reflux ratio of 0.1-20, and more preferably has a top pressure of 0.1-0.8 MPa and a reflux ratio of 0.2-8. The preferred operating temperature of the methanol water washing tower is 25-60°C and the pressure is 0.4-1.0 MPa. The preferred top pressure of the methanol recovery tower is 0.1-0.4 MPa and the reflux ratio is 1-20. The preferred top pressure of the isobutylene light removal tower is 0.1-2.0 MPa and the reflux ratio is less than 300.
[0051] The terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art, unless otherwise specified.
[0052] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with embodiments.
[0053] In the following examples, various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, devices, instruments, equipment, etc. used in the following examples can be obtained from commercial sources.
[0054] Examples 1 to 9
[0055] Process flow such as Figure 1As shown, the MTBE raw material is mixed with the regulator and then input into the reactor 1 filled with the catalyst, and the decomposition reaction product at the outlet of the reactor 1 enters the isobutylene deheaving tower 2; the bottom product of the isobutylene deheaving tower 2 is mainly methanol and contains the regulator, and the bottom material of the isobutylene deheaving tower is sent to the regulator recovery tower 6 for rectification, and methanol is obtained at the top of the regulator recovery tower 6, and the regulator is obtained at the bottom of the tower, which is returned to the reactor 1 for recycling; the top material of the isobutylene deheaving tower 2 enters the methanol water washing tower 3, and the methanol-free isobutylene is obtained at the top of the methanol water washing tower 3, and the bottom material is sent to the methanol recovery tower 4; the top material of the methanol recovery tower 4 is methanol, which is used as a methanol by-product together with the methanol obtained at the top of the regulator recovery tower 6, and the bottom material is water, which is returned to the methanol water washing tower 3 as washing water for recycling; the isobutylene obtained at the top of the methanol water washing tower 3 enters the isobutylene light removal tower 5, and the light components are removed at the top of the tower, and the isobutylene product is obtained at the bottom of the tower.
[0056] Some process conditions are shown in Table 1. The catalyst used in Examples 1 to 3 is a catalyst with silicon dioxide as a carrier and heteropoly acid as an active component; the catalyst used in Examples 4 to 6 is Ni (0.2wt%) / amorphous silicon aluminum; the catalyst used in Examples 7 to 9 is a catalyst with silicon dioxide as a carrier and heteropoly acid and Mg (NO3) 2 as active components. The top pressure of isobutylene de-heavy tower 2 is 0.65MPa, and the reflux ratio is 0.3. The top pressure of methanol water washing tower 3 is 0.6MPa, and the operating temperature is 40°C. The top pressure of methanol recovery tower 4 is 0.3MPa, and the reflux ratio is 8. The top pressure of isobutylene de-light tower 5 is 0.95MPa, and the reflux ratio is 25. The top pressure of regulator recovery tower 6 is 0.15MPa, and the reflux ratio is 0.5. The composition of MTBE raw material, isobutylene product and reaction conversion rate are shown in Table 2.
[0057] Example 10
[0058] The mass fraction of MTBE in the MTBE raw material is 10.6%. Before the MTBE raw material enters the reactor, a light component is removed from it and a heavy component is removed from it to obtain a raw material with a mass fraction of MTBE of 99.1%. Figure 1 The process flow is shown in the figure. Some operating conditions are shown in Table 1. The catalyst used is an acidic molecular sieve. The top pressure of the isobutylene de-heavy tower 2 is 0.6 MPa, and the reflux ratio is 0.6. The top pressure of the methanol water washing tower 3 is 0.7 MPa, and the operating temperature is 40°C. The top pressure of the methanol recovery tower 4 is 0.2 MPa, and the reflux ratio is 10. The top pressure of the isobutylene de-light tower 5 is 0.9 MPa, and the reflux ratio is 20. The top pressure of the regulator recovery tower 6 is 0.2 MPa, and the reflux ratio is 0.9. The composition of MTBE raw material, isobutylene product and reaction conversion rate are shown in Table 2.
[0059] Comparative Example 1
[0060] The difference from Example 1 is that no regulator is added. The isobutylene product composition and reaction conversion rate are shown in Table 2.
[0061] Comparative Example 2
[0062] The difference from Example 8 is that no regulator is added. The isobutylene product composition and reaction conversion rate are shown in Table 2.
[0063] Table 1 Process conditions of Examples 1 to 10
[0064]
[0065]
[0066] Table 2 Raw materials, product composition and conversion rate of Examples 1 to 10 and Comparative Examples 1 to 2
[0067]
[0068] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the embodiments. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. The obvious changes or modifications derived from them are still within the protection scope of the invention.
Claims
1. A method for preparing isobutylene by decomposing MTBE, comprising the following steps: performing a decomposition reaction on an MTBE raw material in the presence of a catalyst, and separating the decomposition reaction product to obtain an isobutylene product; It is characterized in that In the decomposition reaction system, a regulator is also present; The regulator is one of methylcyclohexanone and phenol or a mixture of the two, and the mass ratio of the regulator to the MTBE raw material is 0.001-0.05:
1.
2. The method for preparing isobutylene by decomposing MTBE according to claim 1, characterized in that: The mass ratio of the regulator to the MTBE raw material is 0.005-0.03:
1.
3. The method for preparing isobutylene by decomposing MTBE according to claim 1, characterized in that: The regulator is a mixture of phenol and methylcyclohexanone in a mass ratio of 0.05 to 0.5:
1.
4. The method for preparing isobutylene by decomposing MTBE according to claim 3, characterized in that: The regulator is a mixture of phenol and methylcyclohexanone in a mass ratio of 0.1 to 0.3:
1.
5. The method for preparing isobutylene by decomposing MTBE according to claim 1, characterized in that: The decomposition reaction is carried out in a reactor. The regulator and the MTBE raw material are uniformly mixed in a mixer, preheated to 100-350° C., and then enter a reactor filled with a catalyst.
6. The method for preparing isobutylene by decomposing MTBE according to claim 1, characterized in that: The decomposition reaction product is separated by distillation to recover the regulator, and the recovered regulator is circulated for use.
7. The method for preparing isobutylene by decomposing MTBE according to claim 1, characterized in that: The MTBE raw material contains 1% to 99.9999% by mass of MTBE and 0.0001% to 3% by mass of MSBE, and the total mass fraction of MTBE and MSBE is less than or equal to 100%; Before the decomposition reaction of the MTBE raw material, one or more distillation towers are used to remove light components and heavy components; The catalyst is silica gel, cation exchange resin, supported inorganic acid salt, solid phosphoric acid catalyst or acidic molecular sieve; the volume space velocity of the catalyst is 0.01h -1 ~15h -1 ; The reaction temperature of the decomposition reaction is 100° C. to 350° C., and the reaction pressure is 0.1 MPa to 4.0 MPa.
8. The method for preparing isobutylene by decomposing MTBE according to any one of claims 1 to 7, characterized in that: The method for preparing isobutylene by decomposing MTBE is one of method A and method B: Method A: MTBE raw material is mixed with a regulator and then enters a reactor filled with a catalyst, the decomposition reaction product at the outlet of the reactor enters an isobutylene deweighting tower for distillation and separation, the bottom material of the isobutylene deweighting tower is sent to a regulator recovery tower for distillation, methanol is obtained at the top of the regulator recovery tower, and the regulator is obtained at the bottom of the tower, which is returned to the reactor for recycling; the top material of the isobutylene deweighting tower enters a methanol washing tower for washing, and methanol-free isobutylene, i.e., isobutylene product, is obtained at the top of the methanol washing tower; the bottom material of the methanol washing tower is sent to a methanol recovery tower, and the top material of the methanol recovery tower is methanol, which is used as a methanol by-product together with the methanol obtained at the top of the regulator recovery tower, and the bottom material is water, which is returned to the methanol washing tower as washing water for recycling; Method B: MTBE raw material is mixed with a regulator and then enters a reactor filled with a catalyst. The decomposition reaction product at the outlet of the reactor first enters a methanol water washing tower, the bottom material is sent to a methanol recovery tower, and the top material of the methanol recovery tower is sent to a regulator recovery tower for rectification. Methanol by-product is obtained at the top of the tower, and the regulator is obtained at the bottom of the tower, which are returned to the reactor for recycling; the bottom discharge of the methanol recovery tower is water, which is returned to the methanol water washing tower for recycling as washing water; the isobutylene obtained at the top of the methanol water washing tower is passed through an isobutylene deheaving tower to remove the heavy components to obtain an isobutylene product.
9. The method for preparing isobutylene by decomposing MTBE according to claim 8, characterized in that: In the method A, the decomposition reaction product at the outlet of the reactor first enters a vapor-liquid separation tank for vapor-liquid flash separation, and then the gas phase at the top of the vapor-liquid separation tank is compressed by a compressor and sent to an isobutylene deweighting tower, and the bottom liquid phase is pumped into the isobutylene deweighting tower; In the method A, isobutylene without methanol is transported to an isobutylene light component removal tower, and after the light components are removed, an isobutylene product is obtained at the bottom of the tower; In the method B, the isobutylene obtained from the top of the methanol water washing tower is first passed through an isobutylene light-removing tower to remove the light components, and the bottom material is then passed through an isobutylene heavy-removing tower to remove the heavy components to obtain an isobutylene product.
10. The method for preparing isobutylene by decomposing MTBE according to claim 8, characterized in that: In the method A and the method B, The pressure of the isobutylene deweighting tower is 0.4-1.0MPa, and the reflux ratio is 0.3-10; The top pressure of the regulator recovery tower is 0.1-1.5 MPa, and the reflux ratio is 0.1-20; The operating temperature of the methanol water scrubber is 25-60°C and the pressure is 0.4-1.0MPa; The top pressure of the methanol recovery tower is 0.1-0.4 MPa, and the reflux ratio is 1-20; The top pressure of the isobutylene light removal tower is 0.1-2.0 MPa, and the reflux ratio is less than 300.