Work starting method of ETBE device and production method of ETBE

Abstract

The invention discloses a start-up method of an ETBE device and a production method of ETBE. The ETBE device comprises a catalytic rectifying tower newly provided with an ETBE catalyst bed, the start-up method comprises the following steps: introducing methanol into the catalytic rectifying tower to displace moisture in the ETBE catalyst bed, and when the mass content of water in a discharged material of the catalytic rectifying tower is less than 15%, starting up the catalytic rectifying tower; and introducing a C4 material into the catalytic rectifying tower, and removing methanol in the catalytic rectifying tower and the ETBE catalyst bed layer of the catalytic rectifying tower. The method has the advantages that a large amount of hydrous ethanol is not generated in the catalyst dehydration process, residual ethanol does not exist in the catalyst, dehydration raw materials are easy to obtain, the dehydration effect is enhanced, the time for starting a device is short, and the quantity of unqualified products is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of ETBE preparation, and in particular to a start-up method of an ETBE device and a production method of ETBE. Background Art

[0002] The production of ETBE by the reaction of mixed C4 and ethanol usually uses a sulfonic acid ion exchange resin catalyst. The fresh catalyst usually contains about 50% water. If it is used directly for ETBE production, the water in the catalyst will react with the isobutylene in the mixed C4 to form tert-butanol, resulting in a significant reduction in the purity of the ETBE product. Therefore, the water in the catalyst must be removed before being used in the etherification reaction.

[0003] CN103127961 discloses a catalyst swelling soaking process for a reactor of an MTBE industrial device, including the processes of introducing, soaking, and dehydrating, wherein the etherified mixed C4 is introduced into a reactor equipped with a new catalyst by a centrifugal pump, the reactor is at room temperature, the reactor pressure is increased, the reactor entrance and exit are closed, and the mixed C4 is withdrawn to a static tank by self-pressure after standing, and the material entering the static tank is then dehydrated and sent out after standing. The mixed C4 has a weak polarity, and a higher reactor pressure is required to replace the water in the catalyst, and the water in the deep pores of the catalyst cannot be removed. The dehydration effect is general, and a certain amount of unqualified products with excessive tert-butyl alcohol content will still be produced in the early stage of operation; it takes a long time and multiple times to soak the catalyst, which takes a long time and uses a lot of carbon four materials. Summary of the invention

[0004] The invention provides a start-up method for an ETBE device and a production method for ETBE, which have the advantages that a large amount of hydrous ethanol is not generated during the catalyst dehydration process, no residual ethanol exists in the catalyst, dehydration raw materials are easily available, the dehydration effect is enhanced, the start-up time of the device is short, and the amount of unqualified products is greatly reduced.

[0005] The inventor of the present invention disclosed a treatment process and treatment device of ETBE catalyst in Chinese Patent No. 202211049176, which uses ETBE to remove moisture from the catalyst, and ETBE and water are discharged to the reflux tank of the catalytic distillation tower, and sedimentation and stratification are carried out in the reflux tank. The water in the lower layer is discharged from the device, and the ETBE in the upper layer is recycled. For a newly built ETBE device, the dehydrated raw material ETBE is not easy to obtain before the device is put into operation.

[0006] The inventors of the present invention have found in their research that ETBE catalysts usually use ethanol displacement dehydration to produce a large amount of ethanol-water solution, and the ethanol therein is recovered by distillation. Since ethanol and water form an azeotrope, the ethanol recovered by distillation contains about 5% water by mass. Therefore, a large amount of hydrous ethanol will be produced in the catalyst dehydration process. These hydrous ethanol cannot be used for ETBE production and are difficult to handle because the water therein will react with the isobutylene in the mixed C4 to produce tert-butanol, resulting in the tert-butanol content of the ETBE product exceeding the standard. At the same time, after the ethanol displacement dehydration, a large amount of residual ethanol is contained in the device and the catalyst. For a long time at the beginning of the start-up, a large amount of excess ethanol from the reaction enters the catalytic distillation tower. Since the azeotropic composition of ethanol in the azeotrope formed by C4-ethanol is particularly low, ethanol exceeds the highest concentration composition of the azeotrope and cannot be azeotropically distilled from the top of the tower, but can only enter the bottom of the tower, causing the ethanol content in the ETBE product at the bottom of the tower to exceed the standard by a large amount, resulting in a large amount of unqualified products with excessive ethanol in the early stage of the start-up, and a long start-up time.

[0007] In order to solve the above problems, the present invention provides a start-up method of an ETBE device, wherein the ETBE device includes a reaction unit newly equipped with an ETBE catalyst bed, and the start-up method includes:

[0008] Methanol is introduced into the reaction unit to displace the water in the ETBE catalyst bed. When the water mass content in the discharged material from the reaction unit is less than 15%, a C4 material is introduced into the reaction unit to remove the methanol in the reaction unit and its ETBE catalyst bed. The isobutylene mass content in the C4 material is less than 1.0%.

[0009] In the present invention, the reaction unit of the ETBE device includes the following three configurations:

[0010] Form 1: The reaction unit of the ETBE device includes at least one reactor but does not include a catalytic distillation column;

[0011] Form 2: The reaction unit of the ETBE device includes at least one catalytic distillation column but does not include a reactor;

[0012] Form three: The reaction unit of the ETBE device includes a reactor and a catalytic distillation tower, wherein the reactor and the catalytic distillation tower are connected in series.

[0013] In some embodiments of the present invention, the reaction unit of the ETBE device includes a reactor, in which a bed of ETBE catalyst is newly installed, and the start-up method includes:

[0014] a) introducing methanol into the reactor to displace the water in the ETBE catalyst bed in the reactor, wherein when the water content in the discharge material of the reactor is less than 15% by weight, performing step b);

[0015] b) introducing C4 material into the reactor to remove methanol in the reactor and its ETBE catalyst bed.

[0016] In other embodiments of the present invention, the reaction unit of the ETBE device includes a catalytic distillation tower, in which a ETBE catalyst bed is newly installed, and the start-up method includes:

[0017] a) introducing methanol into the catalytic distillation tower to displace the water in the ETBE catalyst bed in the catalytic distillation tower, wherein when the water content of the discharged material from the catalytic distillation tower is less than 15%, step b) is performed;

[0018] b) introducing C4 material into the catalytic distillation tower to remove methanol in the catalytic distillation tower and in its ETBE catalyst bed.

[0019] In other embodiments of the present invention, the reaction unit of the ETBE device comprises a reactor and a catalytic distillation tower connected in series in sequence along the material flow direction, wherein each of the reactor and the catalytic distillation tower is newly equipped with an ETBE catalyst bed. The start-up method comprises:

[0020] a) introducing methanol into the reactor, or introducing methanol into the reactor and the catalytic distillation tower respectively, to displace the water in the ETBE catalyst bed of the reactor and the catalytic distillation tower,

[0021] Wherein, when the water mass content in the discharged materials from the reactor and the catalytic distillation tower is less than 15% respectively, step b) is carried out;

[0022] b) introducing a C4 material into the reactor, or introducing a C4 material into the reactor and the catalytic distillation tower respectively, to remove methanol from the reactor and the catalytic distillation tower and their ETBE catalyst bed.

[0023] Preferably, when the reaction unit includes a reactor, step b) removes methanol from the ETBE catalyst in the reactor by pressure, and preferably the removal conditions of step b) include: the reactor pressure is controlled at 0.4-1.0 MPaG, more preferably 0.6-0.8 MPaG, and the reactor temperature is room temperature.

[0024] Preferably, when the reaction unit includes a catalytic distillation tower, step b) removes methanol from the ETBE catalyst in the catalytic distillation tower by distillation. More preferably, the removal conditions of step b) also include: distilling the material in the catalytic distillation tower. Further preferred distillation conditions include: controlling the temperature of the ETBE catalyst bed to 40-80°C, further preferably 40-70°C; controlling the top pressure of the catalytic distillation tower to 0.3-1.0MpaG, further preferably 0.4-0.5MpaG; controlling the reflux ratio to 0.5-15, further preferably 0.5-7.

[0025] Preferably, the removal conditions in step b) also include: the volume space velocity of the C4 material passing through the ETBE catalyst is 0.2-10h -1 , more preferably 1-5h -1 .

[0026] Preferably, the replacement conditions of step a) include: normal temperature and pressure, and a volume space velocity of methanol passing through the ETBE catalyst of 0.5-10h -1 , more preferably 1-5h -1 .

[0027] Preferably, step b) is performed when the water mass content in the discharge material of the reactor and / or the catalytic distillation tower is less than 10%.

[0028] Preferably, the mass content of isobutylene in the C4 material is less than 0.5%, more preferably less than 0.1%.

[0029] Preferably, the C4 material comes from at least one of the C4 in the oil refining process, the C4 in the ethylene cracking process, the C4 in the methanol to olefins process, the C4 remaining after the etherification reaction to produce MTBE and ETBE, or the light C4 produced by the 1-butene separation device.

[0030] Preferably, the water content in the fresh ETBE catalyst is 10%-80% by mass.

[0031] Preferably, the ETBE catalyst is an ion exchange resin catalyst, more preferably a sulfonic acid type cation exchange resin catalyst.

[0032] Preferably, the number of reactors in the ETBE device is two or more, connected in series or in parallel.

[0033] Preferably, the ETBE device further comprises: an extraction tower and a distillation recovery tower;

[0034] The distillation recovery tower is connected to the reactor and / or the catalytic distillation tower, and is used to separate water and methanol from the reactor and / or the catalytic distillation tower;

[0035] The extraction tower is connected to the top of the catalytic distillation tower and is used for extracting and separating the top discharge of the catalytic distillation tower.

[0036] Preferably, the extractant in the extraction column comprises water;

[0037] More preferably, the distillation recovery tower is connected to the extraction tower, so as to return the water separated by the distillation recovery tower to the extraction tower as an extractant.

[0038] The invention discloses a method for producing ETBE. After the ETBE device is started up by the start-up method of the invention, ethanol and C4 raw materials are introduced into a reactor or a catalytic distillation tower to produce ETBE.

[0039] Preferably, when the methanol mass content in the discharge material of the reactor and / or the catalytic distillation tower is less than 10%, more preferably less than 3%, ethanol and C4 raw materials are introduced into the reactor or the catalytic distillation tower to produce ETBE.

[0040] Preferably, the ETBE device further comprises an extraction tower and a distillation recovery tower; wherein the distillation recovery tower is connected to the extraction tower to separate water and ethanol from the extraction tower;

[0041] The extraction tower is connected to the top of the catalytic distillation tower and is used to extract and separate the top discharge of the catalytic distillation tower;

[0042] It is more preferred that all materials in the extraction tower and the distillation recovery tower be discharged before ethanol and C4 raw materials are introduced into the reactor or catalytic distillation tower to produce ETBE, and it is further preferred that all materials in the extraction tower and the distillation recovery tower be discharged before ethanol and C4 raw materials are introduced into the reactor and the catalytic distillation tower respectively to produce ETBE.

[0043] Through the above technical scheme, the present invention first uses methanol to remove the moisture in the fresh ETBE catalyst in the device, and then uses C4 material to remove the methanol in the device and the catalyst. Compared with the conventional use of ethanol to remove the moisture in the catalyst, a large amount of water-containing ethanol is not generated; there is no residual ethanol in the catalyst at the initial start-up, and there is no unqualified product due to excessive residual ethanol; the water in the catalyst is further removed in the process of removing methanol from C4, so that the dehydration effect is enhanced, and there is no unqualified product due to excessive tert-butyl alcohol at the initial start-up; C4 is easy to obtain after dehydrating the raw materials methanol and ether; the residual C4 in the catalyst will not affect the purity of the product; the start-up time of the device is short, and the amount of unqualified products is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a flow chart of a method for starting up an ETBE device according to some embodiments of the present invention;

[0045] Figure 2is a flow chart of a method for starting up an ETBE device according to other embodiments of the present invention;

[0046] Figure 3 is a flow chart of a method for starting up an ETBE device according to other embodiments of the present invention;

[0047] Figure 4 is a flow chart of a method for starting up an ETBE device according to other embodiments of the present invention;

[0048] Figure 5 It is a flow chart of the start-up method of the ETBE device in other embodiments of the present invention.

[0049] Description of Reference Numerals

[0050] 1 reactor; 2 catalytic distillation tower; 3 extraction tower; 4 distillation recovery tower; 5 distillation tower. DETAILED DESCRIPTION

[0051] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0052] In the present invention, unless otherwise specified, directional words such as "up, down, left, right" generally refer to up, down, left, right as shown in the reference drawings; "inside and outside" refer to inside and outside relative to the outline of each component itself.

[0053] The present invention discloses a method for starting up an ETBE device, such as Figure 1 As shown, the ETBE device includes a reaction unit newly equipped with an ETBE catalyst bed, and the start-up method includes:

[0054] Methanol is introduced into the reaction unit to displace the water in the ETBE catalyst bed. When the water mass content in the discharged material of the reaction unit is less than 15%, C4 material is introduced into the reaction unit to remove the methanol in the reaction unit and its ETBE catalyst bed.

[0055] In some embodiments of the present invention, Figure 1 As shown, the reaction unit of the ETBE device includes a reactor 1 and a catalytic distillation tower 2 which are connected in series in sequence along the material flow direction. The reactor 1 and the catalytic distillation tower 2 are each newly equipped with an ETBE catalyst bed. The start-up method includes dehydrating the fresh ETBE catalyst in the reactor and the catalytic distillation tower, specifically including:

[0056] a) feeding methanol into the reactor 1, preferably feeding methanol into the reactor 1 and the catalytic distillation tower 2 respectively, to displace the water in the ETBE catalyst bed in the reactor, the reactor is connected to the catalytic distillation tower, the material containing methanol in the reactor can be directly discharged, or can be passed into the catalytic distillation tower to further displace the water in the ETBE catalyst bed in the catalytic distillation tower; wherein, when the water mass content in the discharged materials of the reactor 1 and the catalytic distillation tower 2 is less than 15% respectively, step b) is carried out;

[0057] b) introducing a C4 material into the reactor 1, preferably introducing a C4 material into the reactor 1 and the catalytic distillation tower 2, respectively, to remove methanol from the reactor and the catalytic distillation tower and their ETBE catalyst bed.

[0058] In some embodiments of the present invention, methanol is separated from the ETBE catalyst in the reactor by pressure, and preferably the removal conditions of step b) include: the pressure of reactor 1 is controlled at 0.4-1.0 MPaG, more preferably 0.6-0.8 MPaG.

[0059] In some embodiments of the present invention, methanol is separated from the ETBE catalyst in the catalytic distillation tower 2 by distillation. The removal conditions of the preferred step b) also include: distilling the material in the catalytic distillation tower 2 so that the methanol inside the catalyst leaves the catalyst with C4 by azeotropic action under heating conditions, and the top discharge is an azeotrope of C4 and methanol, and the bottom discharge is methanol and a small amount of water. The preferred distillation conditions include: controlling the temperature of the ETBE catalyst bed to 40-80°C, preferably 40-70°C; controlling the top pressure of the catalytic distillation tower 2 to 0.3-1.0MpaG, preferably 0.4-0.5MpaG; controlling the reflux ratio to 0.2-15, preferably 0.5-7.

[0060] In some embodiments of the present invention, the removal conditions in step b) further include: the volume space velocity of the C4 material passing through the ETBE catalyst is 0.5-10h -1 , preferably 1-5h -1 .

[0061] In some embodiments of the present invention, the replacement conditions of step a) include: normal temperature and pressure, and a volume space velocity of methanol passing through the ETBE catalyst of 0.5-10h -1 , preferably 1-5h -1 .

[0062] In order to reduce the amount of methanol used, in some embodiments of the present invention, the methanol-containing material at the bottom of the reactor 1 is circulated back to the ETBE catalyst bed of the reactor 1 for multiple times by a pump, and / or the methanol-containing material in the bottom of the catalytic distillation tower 2 is circulated back to the ETBE catalyst bed of the catalytic distillation tower 2 for multiple times by a pump. In the present invention, as long as the methanol-containing material can be returned to the top of the ETBE catalyst bed in the catalytic distillation tower, there are no other special requirements. For example, it can enter the tower through the reflux feed port of the catalytic distillation tower, or through the ethanol feed port of the catalytic distillation tower. It can enter the tower through one catalytic distillation tower ethanol feed port or through two or more catalytic distillation tower ethanol feed ports. The present invention will not be repeated here.

[0063] In some embodiments of the present invention, when the water content in the discharged material from the reactor 1 or the catalytic distillation tower 2 is less than 10% by mass, performing step b) can achieve a better dehydration effect.

[0064] In the present invention, the mass content of isobutylene in the C4 material used for removing methanol is less than 1.0%, preferably less than 0.5%, more preferably less than 0.4%, and further preferably less than 0.1%.

[0065] In some embodiments of the present invention, the C4 material comes from at least one of the C4 in the oil refining process, the C4 in the ethylene cracking process, the C4 in the methanol to olefins process, or the C4 remaining after the etherification reaction to produce MTBE and ETBE (referred to as post-etherification C4, the mass content of isobutylene in the post-etherification C4 is usually less than 0.4% or even less than 0.1%), or the light C4 produced by the 1-butene separation device.

[0066] In some embodiments of the present invention, the water content in the fresh ETBE catalyst is 10%-80% by mass.

[0067] In some embodiments of the present invention, the filling form of the ETBE catalyst in the catalytic distillation tower is selected from bulk, bundled or modular; commonly used ETBE catalysts can be used in the present invention. In some embodiments of the present invention, the ETBE catalyst is an ion exchange resin catalyst, preferably a sulfonic acid type cation exchange resin catalyst.

[0068] In some embodiments of the present invention, the reactor 1 is selected from a mixed bed reactor, an adiabatic fixed bed reactor, a shell-and-tube fixed bed reactor or an expanded bed reactor.

[0069] In order to recycle methanol and water, in some embodiments of the present invention, Figure 2As shown, the ETBE device also includes a distillation recovery tower 4; wherein the distillation recovery tower 4 is connected to the reactor 1 and / or the catalytic distillation tower 2, and is used to separate water and methanol from the reactor 1 and / or the catalytic distillation tower 2; specifically, in step a), the reactor is at room temperature and pressure, methanol enters the reactor, and the water inside the reactor catalyst is displaced, and the reactor outlet materials are methanol and water, and the reactor outlet materials can be passed into the catalytic distillation tower 2, and can also directly enter the distillation recovery tower 4 to be separated into methanol and water; similarly, the discharge from the bottom of the catalytic distillation tower 2 can also be separated into methanol and water through the distillation recovery tower 4.

[0070] In order to recover C4 material and methanol, in some embodiments of the present invention, Figure 3 As shown, the ETBE device includes an extraction tower 3 and a distillation recovery tower 4; the extraction tower 3 is connected to the top of the catalytic distillation tower 2, and is used to extract and separate the azeotropic product of C4 and methanol; in some embodiments of the present invention, the extractant in the extraction tower 3 preferably includes water.

[0071] In some embodiments of the present invention, Figure 3 As shown, it is more preferred that the distillation recovery tower 4 is connected to the extraction tower 3 to return the water in the distillation recovery tower 4 to the extraction tower 3 as an extractant.

[0072] The start-up method of the present invention is also applicable to the start-up production of a MTBE device converted into an ETBE device.

[0073] The invention discloses a method for producing ETBE. After the ETBE device is started up by adopting the start-up method of the invention, ethanol and C4 raw materials are introduced into the reaction unit to produce ETBE.

[0074] In some embodiments of the ETBE production method of the present invention, when the methanol content in the mixed material containing C4 and methanol discharged from the reactor 1 and / or the catalytic distillation tower 2 after C4 demethanolation is less than 10% by mass, preferably less than 3%, ethanol and C4 raw materials are fed into the reactor 1 or the catalytic distillation tower 2 to produce ETBE, preferably ethanol and C4 raw materials are fed into the reactor 1 to produce ETBE. Since a trace amount of methanol remains in the ETBE catalyst, the discharge product of the reactor 1 and / or the catalytic distillation tower 2 contains a small amount of MTBE in addition to ETBE at the initial start-up. As the start-up time increases, the MTBE content gradually decreases until it disappears.

[0075] In the present invention, Figure 3As shown, the ETBE device includes a reactor 1, a catalytic distillation tower 2, an extraction tower 3 and a distillation recovery tower 4. The reactor 1 and the catalytic distillation tower 2 are connected in series, and the distillation recovery tower 4 is connected to the extraction tower 3 for separating water and ethanol from the extraction tower 3; the extraction tower 3 is connected to the top of the catalytic distillation tower 2 for extracting and separating the top discharge of the catalytic distillation tower 2 (the azeotrope of ethanol and C4).

[0076] In some embodiments of the ETBE production method of the present invention, before ethanol and C4 raw materials are introduced into the reactor 1 to produce ETBE, all the materials in the extraction tower 3 and the distillation recovery tower 4 are unloaded. Specifically, in step b), when the top and bottom discharges of the catalytic distillation tower are separated into C4, methanol and water by the extraction tower 3 and the distillation recovery tower 4, all the materials in the extraction tower 3 and the distillation recovery tower 4 are unloaded after the separation is completed, and then ethanol and C4 raw materials are introduced to produce ETBE. In the process of producing ETBE, C4, ethanol and water can be extracted and separated by the extraction tower 3 and the distillation recovery tower 4. The operation of unloading all the materials in the extraction tower 3 and the distillation recovery tower 4 can remove the methanol in the ETBE device more cleanly, further shortening the subsequent start-up time.

[0077] The present invention is further described below by way of implementation, but the present invention is not limited thereto.

[0078] Example 1

[0079] use Figure 3 The process flow shown in the figure is to carry out the following steps in sequence: a) methanol is used to remove the water in the ETBE catalyst loaded in the reactor 1 and the catalytic distillation tower 2. The ETBE catalyst is a sulfonic acid type cation exchange resin catalyst, and the water content in the catalyst is 50%. Methanol enters the reactor 1, and the material at the reactor outlet enters the catalytic distillation tower 2. The catalytic distillation tower reflux pump is used to send the material containing methanol in the tower bottom to the reaction section. The reactor 1 and the catalytic distillation tower 2 are both at room temperature and pressure. The volume space velocity of methanol passing through the catalyst in the reactor is 2h -1 The catalyst volume space velocity of the catalytic distillation tower is 1h -1 ; Enter the tower through the reflux feed port of the catalytic distillation tower, and the bottom discharge enters the distillation recovery tower 4 to separate into methanol and water; when the water mass content of the material discharged from the catalytic distillation tower is 10%, proceed to step b);

[0080] b) Using post-etherification C4 to remove methanol in reactor 1 and catalytic distillation tower 2 and its catalyst, the post-etherification C4 comes from the C4 remaining after the C4 in the oil refining process undergoes etherification reaction to produce MTBE, and the mass content of isobutylene in the post-etherification C4 is 0.05%. The post-etherification C4 enters reactor 1, and the pressure of reactor 1 is 0.7MpaG and the temperature is room temperature. The material at the outlet of reactor 1 enters catalytic distillation tower 2, which is heated by the heat source of the tower reactor to maintain the catalyst bed temperature of the reaction section of the catalytic distillation tower at 40-60°C, the top pressure of the catalytic distillation tower is controlled at 0.5MPaG, the reflux ratio is controlled at 1.0, and the discharge from the tower reactor is methanol and a small amount of water. The material discharged from the top of the tower enters the extraction tower, and the methanol therein is extracted with water as the extractant. The ether discharged from the top of the extraction tower is recovered by the C4 discharge device. The methanol and water discharged from the bottom of the extraction tower are separated into methanol and water by the distillation recovery tower. The water is discharged from the bottom of the distillation recovery tower and returned to the extraction tower for recycling. The excess water is discharged from the discharge device, and the methanol is discharged from the top of the distillation recovery tower. The volume space velocity of C4 passing through the catalyst in the reactor is 3h -1 The catalyst volume space velocity of the catalytic distillation tower is 2h -1 When the methanol content in the reactor discharge is 1.8% by mass and the methanol content in the catalytic distillation tower top discharge is 2.9% by mass, the reactor stops feeding ether and C4, and step c) is performed;

[0081] c) ethanol and a C4 raw material containing 22% by mass of isobutylene are introduced into the reactor 1, and the outlet material of the reactor 1 enters the catalytic distillation tower 2, and the production of ETBE is started; wherein, the reactor inlet temperature is controlled at 45°C, the top pressure of the catalytic distillation tower is controlled at 0.5MPaG, the reflux ratio is controlled at 1.0, the top temperature of the catalytic distillation tower is 55°C, the bottom temperature of the tower is 142°C, the bottom discharge of the catalytic distillation tower is the product ETBE, the top material enters the extraction tower 3, and the ethanol therein is extracted with water as an extractant, the ethanol and water discharged from the bottom of the extraction tower are separated into ethanol and water through the distillation recovery tower 4, the water is discharged from the bottom of the distillation recovery tower 4, and returned to the extraction tower 3 for recycling, and the ethanol is discharged from the top of the distillation recovery tower 4.

[0082] The ETBE catalyst dehydration process does not produce difficult-to-handle aqueous ethanol. The composition of the product ETBE after 83 hours and 93 hours of operation is shown in Table 1.

[0083] Example 2

[0084] The same conditions as in Example 1 are used, except that: in step b), after the reactor 1 stops feeding ether and C4, all the materials in the extraction tower 3 and the distillation recovery tower 4 are unloaded, and then step c) is performed;

[0085] The ETBE catalyst dehydration process does not produce difficult-to-handle aqueous ethanol. The composition of the product ETBE after 83 hours of operation is shown in Table 1.

[0086] Example 3

[0087] The same conditions as in Example 2 are used, except that: a) when the water content in the materials discharged from the reactor 1 and the catalytic distillation tower 2 is 8%, step b) is performed, the isobutylene content in the C4 after etherification in step b) is 0.2%, the pressure of the reactor 1 is 0.6 MPaG, the catalyst bed temperature in the reaction section of the catalytic distillation tower 2 is maintained at 50-65°C, the top pressure of the catalytic distillation tower is controlled at 0.6 MPaG, the reflux ratio is controlled at 0.8, and the volume space velocity of the C4 passing through the catalyst in the reactor is 5 h -1 The volumetric space velocity of the catalytic distillation tower is 4h -1 When the methanol content in the reactor discharge is 1.6% by mass and the methanol content in the catalytic distillation tower top discharge is 2.5% by mass, the reactor 1 stops feeding ether and C4;

[0088] The ETBE catalyst dehydration process does not produce difficult-to-handle aqueous ethanol. The composition of the product ETBE after 83 hours of operation is shown in Table 1.

[0089] Example 4

[0090] use Figure 4 The process flow shown in the figure is to carry out the following steps in sequence: a) using methanol to remove the water in the ETBE catalyst loaded in the catalytic distillation tower 2, the ETBE catalyst is a sulfonic acid type cation exchange resin catalyst, and the water content in the catalyst is 45%. Methanol enters the catalytic distillation tower 2, and the catalytic distillation tower reflux pump is used to send the methanol-containing materials in the tower bottom to the top of the reaction section, and enter the tower through the catalytic distillation tower reflux feed port. The catalytic distillation tower is at normal temperature and pressure, and the volume space velocity of methanol passing through the catalyst in the reaction section is 3h -1 ; The discharge from the bottom of the tower enters the distillation recovery tower 4 and is separated into methanol and water, and the methanol and water are discharged from the device for recovery; when the water content of the material discharged from the catalytic distillation tower 2 is 14%, step b) is performed;

[0091] b) using post-etherified C4 to remove methanol in catalytic distillation tower 2 and catalyst, the post-etherified C4 comes from C4 in ethylene cracking process and is the remaining C4 after etherification reaction to produce MTBE, and the mass content of isobutylene in post-etherified C4 is 0.12%. Post-etherified C4 enters catalytic distillation tower 2, which is heated by the heat source of the tower bottom to maintain the catalyst bed temperature of the reaction section of catalytic distillation tower 2 at 55-60°C, the top pressure of catalytic distillation tower 2 is controlled at 0.6MPaG, and the reflux ratio is controlled at 1.6, the bottom discharge is methanol and a small amount of water, which enters distillation recovery tower 4 to be separated into methanol and water. The top discharge of catalytic distillation tower 2 enters extraction tower 3, and methanol therein is extracted with water as an extractant, the post-etherified C4 discharge device of the extraction tower top is recovered, and the methanol aqueous solution discharged from the bottom of the extraction tower also enters distillation recovery tower 4 to be separated into methanol and water, water is discharged from the bottom of the distillation recovery tower and returned to the extraction tower 3 for recycling, the excess water is discharged, and the methanol is recovered from the top discharge device of the distillation recovery tower 4. The volumetric space velocity of the catalyst of the etherified C4 through the catalytic distillation tower 2 is 1h -1 When the methanol content in the top discharge of the catalytic distillation tower 2 is 3.8%, the ether feed is stopped and step c) is performed;

[0092] c) introducing ethanol and a C4 raw material containing 6% isobutylene by mass into a catalytic distillation tower 2, and starting to produce ETBE; the top pressure of the catalytic distillation tower 2 is controlled at 0.6MPaG, the reflux ratio is controlled at 1.3, the top temperature of the catalytic distillation tower is 59°C, and the bottom temperature is 147°C. The bottom discharge of the catalytic distillation tower is the product ETBE, and the top material enters an extraction tower 3, where ethanol is extracted with water as an extractant. The ethanol and water discharged from the bottom of the extraction tower are separated into ethanol and water through a distillation recovery tower 4, and the water is discharged from the bottom of the distillation recovery tower 4 and returned to the extraction tower 3 for recycling, and the ethanol is discharged from the top of the distillation recovery tower;

[0093] The ETBE catalyst dehydration process does not produce difficult-to-handle aqueous ethanol. The composition of the product ETBE after 93 hours of operation is shown in Table 1.

[0094] Example 5

[0095] use Figure 5 The process flow shown in the figure is to carry out the following steps in sequence: a) methanol is used to remove the water in the ETBE catalyst loaded in the reactor 1. The ETBE catalyst is a sulfonic acid type cation exchange resin catalyst, and the water content in the catalyst is 55%. Methanol enters the reactor 1, and the reactor 1 is at room temperature and pressure. The volume space velocity of methanol passing through the catalyst of the reactor 1 is 4h -1 The discharge from the reactor 1 enters the distillation recovery tower 4 and is separated into methanol and water, and the methanol and water are discharged from the device for recovery; when the water content of the material discharged from the reactor 1 is 5%, step b) is performed;

[0096] b) Use C4 to remove methanol in reactor 1 and catalyst. C4 comes from light C4 produced by 1-butene separation device, and the mass content of isobutylene in light C4 is 0.01%. Light C4 enters reactor 1, and the pressure of reactor 1 is 0.9MpaG and the temperature is room temperature. The material at the outlet of reactor 1 enters distillation tower 5, which is heated by the heat source of the tower bottom. The pressure at the top of distillation tower 5 is controlled at 0.55MPaG, and the reflux ratio is controlled at 3. The discharge from the tower bottom is methanol and a small amount of water, which enters distillation recovery tower 4 to be separated into methanol and water. The discharge from the top of distillation tower 5 enters extraction tower 3, and the methanol therein is extracted with water as the extractant. The light C4 discharge device of the top of the extraction tower is recovered, and the methanol-water solution discharged from the bottom of the extraction tower also enters distillation recovery tower 4 to be separated into methanol and water. Water is discharged from the bottom of the distillation recovery tower and returned to the extraction tower 3 for recycling. Excess water is discharged from the discharge device, and methanol is recovered from the discharge device at the top of the distillation recovery tower 4. The volumetric space velocity of light C4 passing through the catalyst of reactor 1 is 6h -1 When the methanol content in the discharge of reactor 1 is 2.4%, the introduction of light C4 is stopped and step c) is performed;

[0097] c) introducing ethanol and isobutylene with a mass content of 12% C4 raw materials into the reactor 1, and starting the production of ETBE; the inlet temperature of the reactor 1 is 40° C., the outlet material of the reactor 1 enters the distillation tower 5, the top pressure of the distillation tower 5 is controlled at 0.55 MPaG, the reflux ratio is controlled at 0.8, the top temperature of the distillation tower is 56° C., the bottom temperature of the distillation tower is 143° C., the bottom discharge of the distillation tower is the product ETBE, the top material enters the extraction tower 3, and the ethanol therein is extracted with water as the extraction agent, the ethanol and water discharged from the bottom of the extraction tower are separated into ethanol and water through the distillation recovery tower 4, the water is discharged from the bottom of the distillation recovery tower 4, and returned to the extraction tower 3 for recycling, and the ethanol is discharged from the top of the distillation recovery tower;

[0098] The ETBE catalyst dehydration process does not produce difficult-to-handle aqueous ethanol. The composition of the product ETBE after 93 hours of operation is shown in Table 1.

[0099] Comparative Example 1

[0100] The same conditions as in Example 1 were used, except that the methanol in step a) was replaced with ethanol; and step b) was omitted.

[0101] The ETBE catalyst dehydration process produced a large amount of water-containing ethanol that was difficult to handle. The composition of the ETBE product at 93 hours and 146 hours after start-up is shown in Table 1.

[0102] Table 1: Product ETBE composition and indicators

[0103]

[0104]

[0105] The results of Example 1 and Comparative Example 1 in Table 1 show that, compared with the conventional use of ethanol to remove moisture from the catalyst, in addition to not producing a large amount of hydrous ethanol during the start-up process; there is no residual ethanol in the catalyst after the start-up, and there are no unqualified products due to excessive residual ethanol; there are no unqualified products due to excessive tert-butyl alcohol; after the start-up of the device, the ETBE product reaches the qualified index in a short time and the amount of unqualified products is greatly reduced.

[0106] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for starting up an ETBE device, characterized in that: The ETBE unit includes a reaction unit newly equipped with an ETBE catalyst bed. The startup method includes: Methanol is introduced into the reaction unit to displace the water in the ETBE catalyst bed. When the water mass content in the discharge material of the reaction unit is less than 15%, a C4 material is introduced into the reaction unit to remove the methanol in the reaction unit and its ETBE catalyst bed, and the isobutylene mass content in the C4 material is less than 1.0%.

2. The start-up method according to claim 1, wherein: The reaction unit of the ETBE device comprises a reactor (1), wherein the reactor (1) is newly equipped with an ETBE catalyst bed. The start-up method comprises: a) introducing methanol into the reactor (1) to displace the water in the ETBE catalyst bed in the reactor (1), wherein when the water content in the discharge material of the reactor (1) is less than 15% by weight, step b) is performed; b) introducing C4 material into the reactor (1) to remove methanol in the reactor (1) and its ETBE catalyst bed.

3. The method for starting a work according to claim 1, wherein: The reaction unit of the ETBE device comprises a catalytic distillation tower (2), wherein the catalytic distillation tower (2) is newly equipped with an ETBE catalyst bed. The start-up method comprises: a) introducing methanol into the catalytic distillation tower (2) to displace water in the ETBE catalyst bed in the catalytic distillation tower (2), wherein step b) is performed when the water content of the discharge material from the catalytic distillation tower (2) is less than 15% by weight; b) introducing C4 material into the catalytic distillation tower (2) to remove methanol from the catalytic distillation tower (2) and its ETBE catalyst bed.

4. The method for starting a work according to claim 1, wherein: The reaction unit of the ETBE device comprises a reactor (1) and a catalytic distillation tower (2) connected in series along the material flow direction, wherein each of the reactor (1) and the catalytic distillation tower (2) is newly equipped with an ETBE catalyst bed. The start-up method comprises: a) introducing methanol into the reactor (1), or introducing methanol into the reactor (1) and the catalytic distillation tower (2), respectively, to displace water in the ETBE catalyst bed of the reactor (1) and the catalytic distillation tower (2), wherein step b) is performed when the water content in the discharge materials of the reactor (1) and the catalytic distillation tower (2) is less than 15% by weight respectively; b) introducing a C4 material into the reactor (1), or introducing a C4 material into the reactor (1) and the catalytic distillation tower (2), respectively, to remove methanol from the reactor (1), the catalytic distillation tower (2) and the ETBE catalyst bed.

5. The method for starting a work according to any one of claims 1 to 4, wherein: When the reaction unit includes a reactor, the removal conditions of step b) preferably include: the pressure of the reactor (1) is controlled at 0.4-1.0 MPaG, more preferably 0.6-0.8 MPaG, and the temperature of the reactor is room temperature; and / or When the reaction unit includes a catalytic distillation tower, the removal conditions of step b) preferably further include: distilling the material in the catalytic distillation tower (2), preferably the distillation conditions include: controlling the temperature of the ETBE catalyst bed to 40-80°C, preferably 40-70°C; controlling the top pressure of the catalytic distillation tower (2) to 0.3-1.0 MPaG, preferably 0.4-0.5 MPaG; controlling the reflux ratio to 0.2-15, preferably 0.5-7; and / or The removal conditions in step b) also include: the volume space velocity of the C4 material passing through the ETBE catalyst is 0.5-10h -1 , preferably 1-5h -1 .

6. The method for starting a work according to any one of claims 1 to 5, wherein: The replacement conditions of step a) include: normal temperature and pressure, and a volume space velocity of 0.5-10h for methanol to pass through the ETBE catalyst. -1 , preferably 1-5h -1 ; and / or When the water content in the discharge material from the reactor (1) and / or the catalytic distillation column (2) is less than 10% by mass, step b) is carried out.

7. The method for starting a work according to any one of claims 1 to 6, wherein: The mass content of isobutylene in the C4 material is less than 0.5%, preferably less than 0.1%; and / or The C4 material comes from at least one of the C4 in the oil refining process, the C4 in the ethylene cracking process, the C4 in the methanol to olefins process, the C4 remaining after the etherification reaction to produce MTBE and ETBE, or the light C4 produced by the 1-butene separation device.

8. The method for starting a work according to any one of claims 1 to 7, wherein: The water content of the fresh ETBE catalyst is 10% to 80% by mass; and / or The ETBE catalyst is an ion exchange resin catalyst, more preferably a sulfonic acid type cation exchange resin catalyst.

9. The method for starting a work according to any one of claims 1 to 8, wherein: The ETBE device further comprises: an extraction tower (3) and a distillation recovery tower (4); The distillation recovery tower (4) is connected to the reactor (1) and / or the catalytic distillation tower (2) and is used to separate water and methanol from the reactor (1) and / or the catalytic distillation tower (2); The extraction tower (3) is connected to the top of the catalytic distillation tower (2) and is used for extracting and separating the top discharge of the catalytic distillation tower (2).

10. The start-up method according to claim 9, wherein: The extractant in the extraction column (3) includes water; Preferably, the distillation recovery tower (4) is connected to the extraction tower (3) to return the water separated by the distillation recovery tower (4) to the extraction tower (3) as an extractant.

11. A method for producing ETBE, characterized in that: After the ETBE device is started up using the start-up method described in any one of claims 1 to 10, ethanol and C4 raw materials are introduced into the reactor (1) or the catalytic distillation tower (2) to produce ETBE.

12. The production method according to claim 11, wherein When the methanol content in the discharge material of the reactor (1) and / or the catalytic distillation tower (2) is less than 10% by mass, preferably less than 3%, ethanol and a C4 raw material are fed into the reactor (1) or the catalytic distillation tower (2), preferably ethanol and a C4 raw material are fed into the reactor (1) to produce ETBE; and / or The ETBE device further comprises an extraction tower (3) and a distillation recovery tower (4); wherein the distillation recovery tower (4) is connected to the extraction tower (3) and is used to separate water and ethanol from the extraction tower (3); The extraction tower (3) is connected to the top of the catalytic distillation tower (2) and is used for extracting and separating the top discharge of the catalytic distillation tower (2); Preferably, before introducing ethanol and C4 raw materials into the reactor (1) or the catalytic distillation tower (2) to produce ETBE, all the materials in the extraction tower (3) and the distillation recovery tower (4) are discharged.

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