WO2011120309A1

WO2011120309A1 - Method and device for co-producing ethyl t-butyl ether and ethanol by coupling integrated separation

Info

Publication number: WO2011120309A1
Application number: PCT/CN2010/079113
Authority: WO
Inventors: 张武平; 张文里; 周山花; 田恒水; 张涵璐; 诸富根; 顾京君
Original assignee: 华东理工大学
Priority date: 2010-04-02
Filing date: 2010-11-25
Publication date: 2011-10-06
Also published as: CN102211982B; CN102211982A

Abstract

Disclosed are a method and a device for co-producing ethyl t-butyl ether and ethanol. Said method for co-producing ethyl t-butyl ether and ethanol is carried out by coupling integrated separation. Said ethyl t-butyl ether is from a reaction product obtained by etherification of ethanol and isobutylene, wherein the reaction product mainly contains a mixture of ethyl t-butyl ether, ethanol and un-reacted C₄ hydrocarbons. Ethyl t-butyl ether obtained by said method may contain less than 1 wt. % of ethanol, and ethanol obtained by said method may contain less than 1 wt. %, even less than 0.5 wt. % of water.

Description

Method and device for preparing ethyl tert-butyl ether and ethanol by coupling integrated separation and co-production

The present invention relates to a method and apparatus for preparing ETBE (ethyl tert-butyl ether), and more particularly to a method and apparatus for co-production of ETBE and ethanol. The method of co-production of ETBE and ethanol is carried out by a coupled integrated separation method.

Background technology

The development of bio-based fuels based on ethanol (EtOH) produced by fermentation has received increasing attention from many countries around the world.

However, fuel ethanol, as the most important bio-based alcohol ether fuel, is one of the key problems in energy consumption and cost control. It is difficult to distill and concentrate ethanol and water near the constant boiling point. On the one hand, if the lower concentration of ethanol is to be concentrated to 80-90% by weight or more, the reflux ratio is required to increase the energy consumption, and if the ethanol is to be concentrated to 90-95.5 wt%, especially 92 -95.5 wt% or so, as its concentration requirements increase, its reflux ratio requires that the energy consumption will increase sharply (see Journal of Energy Resources Technology. 2007, Vol. 129: 332-337); When the azeotropic water content of about 5% by weight is removed to less than 1% by weight, special separation methods such as azeotropic distillation, extractive distillation, adsorption, pervaporation membrane separation, etc. are required, and it is usually necessary to add a small amount of co-solvent and help. Dissolving denaturing agents such as fusels, ethers, etc., to some extent compensate for the disadvantage that ethanol gasoline is prone to phase separation. However, despite the lack of its own functions such as high Reid vapor pressure and low calorific value, fuel ethanol is usually sold at a lower price than gasoline, and in some countries its production cost is even higher than that of gasoline (such as China). ). That is to say, the value of fuel ethanol (ie, function/cost) obtained by the prior art is low, and there is an urgent need to find a method of breaking, among which one of the most critical problems is how to reduce the production process of renewable energy as a self-production process. Energy consumption and cost to improve its economy.

ETBE has become a consensus for use as an excellent gasoline additive.

Typically, ETBE is used as a gasoline additive, such as from ethanol and from steam cracking or catalytic dehydrogenation of butane or the like in a mixed C ₄ hydrocarbon fraction by an etherification reaction of isobutene prepared (see, e.g., US 5248836A, CN 1990443A, CN 1772848A, CN 101195560A, etc.). It is not difficult to make ETBE, but it is adopted. There are many problems to be solved as to what kind of ethanol raw materials to prepare, and to be separated and purified to obtain gasoline additives which are excellent in performance. One of the most critical issues involved is how to reduce the energy consumption and cost of its own production and preparation process as a semi-renewable energy source and improve its economy. As described in a literature relating to the industrial preparation of ethers for gasoline and the separation of alcohols/ethers/hydrocarbons (Pure & App/. Chem., Vol. 67, No. 6, pp. 985-992, 1995.) The investment and energy consumption of the separation process may exceed 50% and 90% of the total investment and energy consumption of the preparation process.

In general, the ethanol raw material for preparing ETBE may be ethanol which is hardly water-containing, or may be an azeotropic ethanol having a water content of about 5% by weight or an aqueous ethanol having a water content of at most 10-15% by weight or more. For example, U.S. Patent No. 5,248,836 A discloses the use of anhydrous ethanol or ethanol containing up to 10% by weight of water to feed from the top of the debutanizer reaction section, and to extract and contain the ethanol and ETBE under the reaction zone. The mixed C _{4 of} isobutylene is subjected to a reaction in a pre-reactor and then to a debutanizer column for a reaction separation process. All of the water in the ethanol can be removed by azeotropy with the hydrocarbons by withdrawing the separated water at the bottom of the condensate tank at the top of the debutanizer column. The problem is, on the one hand, the mixing of C ₄ from different sources. The isobutylene content may vary widely (eg, 8-70 mol%). When the isobutene content may be higher, the stoichiometric ethanol feed will also be larger, often because the remaining C _{4 is} less. A high reflux ratio (return flow) is required to azeotrope the water in the ethanol feed, which may result in higher energy consumption; and when the isobutene content may be lower, the stoichiometric ethanol is substantially The amount of feed will also be less (otherwise it will increase the ethanol content in the ETBE), and the azeotropic water removal capacity of the C ₄ hydrocarbon surplus will not be fully utilized, and may even lead to an increase in the ethanol content of the C ₄ hydrocarbon. On the other hand, since it is not given an example, since the liquid phase below the debutanizer reaction section is completely taken out from the side line, there is no liquid reflux between the side line feed and the side line feed, that is, substantially no separation is possible. Theoretical plates, therefore, may cause severe backmixing of ETBE, resulting in easy deactivation of the catalyst in the reaction zone or a reduction in reaction balance and efficiency, or the presence of a large amount of recirculated C _{4 to} sideline reactor backmixing or dilution. .

Chinese Patent No. 1772848A, CN 1780803A discloses a process for preparing ETBE using a mixture of C- ₄ having a water content of 5 to 30% by volume and isobutylene. Both of these methods can significantly reduce the cost of their products, but they produce a mixture comprising primarily ETBE, ethanol and t-butanol. In the prior art, when ethanol containing a certain amount of water is used as a starting material for preparing ETBE, ETBE is usually not further separated and purified, and more unpurified ethanol in the ETBE product may still cause gasoline. The increase in Reid's vapor pressure may still require a reduction in the amount of gasoline light components such as C ₄ -C ₆ in the summer, and/or may not be suitable for direct blending in the refinery gasoline pool. As a gasoline additive with excellent performance, in order to improve product function and ease of use, especially for direct addition in the process of gasoline blending, and without changing the existing storage, transportation and distribution system, it is best to prepare ETBE products. The ethanol content can be strictly controlled during the process, including the ability to control the ethanol content to less than 1% by weight, if necessary.

In order to reduce the complexity of the ETBE separation and purification treatment, the prior art generally uses low- or substantially anhydrous ethanol, such as ethanol having a water content of less than 1% by weight, or even less than 0.5% by weight, as a raw material for the etherification reaction, which has It is advantageous to increase the conversion and/or selectivity of the etherification reaction. Since low-water ethanol or absolute ethanol has strong water absorption capacity and tendency, water may be inhaled during storage and transportation for preparing ETBE. Chinese Patent CN 101033170A proposes to pass at least two kinds of ethanol with different water contents. A method for dehydrating ethanol by a combination of two membrane separations; Russian Patent RU 2327682A proposes a method for drying and dehydrating ethanol by using the obtained ETBE as a heterogeneous azeotropic entrainer having a water content of at least greater than 1% by weight of ethanol. The two methods are both drying the ethanol to remove the water and then using it as a raw material for the etherification reaction.

Heretofore, the method for separating and purifying ETBE is to strictly control the ethanol content of the debutanizer (referred to as the debutanizer), including, for example, controlling the alcohol/ene reaction ratio to a certain ratio below the stoichiometric amount. Before the debutanizer is passed through a pretreatment, such as water elution to remove some of the alcohol and a certain proportion of azeotropic entrainer such as butane, etc. (see, for example, US 7141705A, US 5447607A, US 6107526A, etc., wherein butane and ethanol The azeotropic composition can be up to about 2% by weight of ethanol) so that the remaining alcohol can be almost completely azeotroped from the top of the debutanizer column with the corresponding hydrocarbon. This makes it more difficult to further increase the conversion of isoolefins in some cases, including, for example, reactive distillation, which is often desired, and it may be necessary to replenish a certain amount of ethanol from the upper portion of the debutanizer. Therefore, strict control of the alcohol content of the debutanizer column may make it difficult or limited to increase the conversion of the isoolefin. In addition, the separation of more ethanol from the top of the debutanizer column also increases the burden of subsequent alcohol removal and recovery. In particular, the ethanol content of the commonly used water-washing alcohol washing liquid is generally low, thereby resulting in The enrichment recovery process requires an additional increase in energy consumption.

There are also some prior art techniques for avoiding the high energy consumption of the alcohol-enriched recovery method by using C ₄ hydrocarbon water to wash away alcohol, and in order to eliminate the azeotropic water content brought about by the recovery of ethanol, even using alcohol adsorption, membrane separation and the like to remove alcohol. Or further distillation to remove the alcohol-free C ₄ hydrocarbons to the debutanizer to carry out the alcohol, and the cut alcohol-containing C ₄ hydrocarbons are sent to a recycling reaction to remove the alcohol, such as US 5609734A, CN 1348945A, etc., will significantly increase investment and / or increase the amount of material processing and increase the complexity of the operation. and also For example, Chinese patent CN 1634832A uses a method of recovering a mixture of alcohol, ether and hydrocarbons from the side line below the feed port of the debutanizer to the pre-reactor cycle to eliminate the subsequent ETBE separation step. The ratio may be quite high, and it may still be unfavorable to recycle a large amount of material similar to the equilibrium composition of the reaction, the effect on the amount of catalyst used in the prereactor and its lifetime or including energy consumption.

On the other hand, if the conversion of isoolefin is increased, it is often difficult to strictly control the content of unreacted ethanol in the debutanizer column, including the possibility of replenishing a certain amount of ethanol from the debutanizer reaction zone. Therefore, according to the position of the material extracted from the debutanizer, the separation and purification methods for preparing ETBE are mainly divided into two categories: First, the material is taken out from the bottom of the debutanizer column for subsequent separation (see, for example, US) 5158652A, US 5250156A, US 5348624A and US 5569787A, etc.); the second is to take material from the side of the debutanizer column for subsequent separation (see, for example, CN 1127243A and US 5607557A, etc.).

The above-mentioned methods for separating and purifying ETBE have their own advantages, but their common defects are: strict requirements on the content of certain components of the material entering the debutanizer column, including the requirement to enter "debutane". The "water content of the column" is at most 1% by weight, the tert-butanol content is at most 1% by weight (see, for example, CN 1127243A and US 5607557A, etc.), and/or adsorption separation, pervaporation membrane separation, azeotropy are employed. Special separation methods such as separation. Such severe operating conditions and/or higher energy separation methods result in a reduction in the commercial value of existing separation and purification preparation ETBE processes.

In summary, the preparation of ETBE involves a plurality of azeotrope systems, separation and/or purification processes of multiple linkages, on the one hand, the method is either primarily directed to a single azeotrope system and/or a single link. When the problem is dealt with, it is often possible to pass the problem or difficulty to other links. On the other hand, the method still solves the problems of each azeotrope system and/or each link one by one, and there is still some kind of one-sidedness and/or limitation. Sex, the commercial value (function/cost) of its overall preparation process is not ideal. Summary of the invention

In order to overcome the above problems, it is an object of the present invention to provide a method and apparatus for co-production of ETBE and ethanol with optimized commercial value (i.e., function/cost). The method of co-production of ETBE and ethanol is carried out by a coupled integrated separation method. The ETBE is derived from a reaction product obtained by etherification reaction of ethanol with isobutylene (such as mixed C ₄ hydrocarbons containing isobutylene from steam cracking or catalytic cracking or butane dehydrogenation) (mainly containing ETBE, ethanol and unreacted a mixture of C ₄ hydrocarbons). The co-production preparation ETBE and B The ETBE obtained by the alcohol process may contain less than 1% by weight of ethanol, i.e., the resulting ETBE product may have a high function as a gasoline additive.

It is also an object of the present invention to provide a co-production with optimized commercial value (i.e., function/cost) that utilizes process stream and/or process separation means and/or process energy to be coupled and integrated with dehydration of ethanol. Method and apparatus for preparing ETBE and ethanol. The method of co-production of ETBE and ethanol is carried out by a coupled integrated separation method. The ethanol is derived from ethanol having a water content of at least greater than 1% by weight (more typically, the water content is greater than 1% to 15% by weight of ethanol). The ethanol obtained by the process for co-production of ETBE and ethanol may contain less than 1% by weight of water, even less than 0.5% by weight of water, may be used as a raw material for the etherification reaction, and/or used as gasoline as needed. additive. gP, the obtained ETBE product can be used as a gasoline additive, while having a high function, the cost can be significantly reduced, and the parallel production can be carried out to substantially remove the azeotropic water-containing ethanol.

ETBE according to the present invention: ETBE, ethanol and unreacted C mainly obtained by etherification reaction of ethanol with isobutylene (such as mixed C ₄ hydrocarbons containing isobutylene from steam cracking or catalytic cracking or butane dehydrogenation) ₄ A mixture of hydrocarbons is obtained by separation and purification, as described in, for example, US 5248836A, CN 1990443A, CN 1772848A, CN 101195560A and the like. Typically, a mixture comprising ETBE and ethanol, obtained from the bottom or side of the debutanizer after the reaction zone, typically contains at least greater than 1% by weight of ethanol, more typically 5-50% by weight of ethanol, more It is common to have 10-40% by weight of ethanol, including, in particular, from the side of the debutanizer column, based on the total weight of ETBE and ethanol (see, for example, CN 1127243 and 1^5607557, etc.). In addition, the mixture containing mainly ETBE and ethanol may also include some other components such as t-butanol (TBA), dimeric isobutylene, ethyl sec-butyl ether (E2BE), diethyl ether (DEE). And C ₅ hydrocarbons, etc., can be basically regarded as ETBE without distinction in the separation and purification process of ETBE and ethanol (except that tert-butanol can be substantially left in the separated and purified ethanol because it is close to the boiling point of ethanol).

The method for preparing ETBE and ethanol according to the invention, the main steps of which are: dehydration separation process of ethanol having a water content of at least more than 1% by weight (more commonly, ethanol having a water content of more than 1% by weight to 15% by weight) And a debutanization step after the reaction zone in the process for preparing the ETBE and another distillation-extraction coupling step, wherein the distillation-extraction coupling step consists of a distillation column and an extraction column. Thus, not only qualified ETBE products can be obtained from the top of the extraction column and/or the bottom of the debutanizer column, but also the azeotropically aqueous ethanol can be substantially removed from the bottom of the distillation column.

The technical solution of the method of the invention is as follows: A method for coupling and separating and co-production of ETBE and ethanol, which is obtained by etherification reaction of ethanol with isobutylene (such as mixed C ₄ hydrocarbons containing isobutylene from steam cracking or catalytic cracking or butane dehydrogenation) The mixture to be separated (abbreviated as a mixture to be separated) containing ETBE, ethanol and unreacted C ₄ hydrocarbons is used as a raw material, and includes the following steps:

a) introducing the mixture to be separated into the first distillation column for dealkylation distillation, and introducing ethanol having a water content of at least greater than 1% by weight into the first distillation column from a side line position not lower than the feed position of the mixture to be separated, in the first distillation The top of the column collects a C ₄ -containing hydrocarbon fraction, wherein the C ₄ -containing hydrocarbon fraction further contains ethanol and water; b) a mixture containing ETBE and ethanol taken from the bottom of the first distillation column or taken sideways, and water content At least greater than 1% by weight of ethanol is introduced into the distillation-extraction coupling zone, wherein the distillation-extraction coupling zone is composed of a second distillation column and an extraction column, and the operating pressure of the second distillation column is lower than that of the first distillation column pressure;

c) collecting the ethanol-containing fraction at the bottom of the second distillation column, feeding the material containing ETBE, ethanol and water obtained at the top of the second distillation column as an extraction feed to the extraction column for extraction, and collecting ethanol at the bottom of the extraction column The extract, the recoverable ethanol, is recycled (eg, reintroduced into the distillation-extraction coupling zone), and the ETBE-containing raffinate is collected at the top of the extraction column;

d) When the mixture containing ETBE and ethanol is taken out from the side of the first distillation column, 0-100% of the ETBE-containing raffinate obtained at the top of the extraction column is recycled to the first distillation column and collected from the bottom of the first distillation column Contains ETBE fractions.

In a preferred embodiment of the present invention, the method comprises a mixture of ETBE, ethanol and unreacted C ₄ hydrocarbons obtained by etherification reaction of ethanol and isobutylene as a raw material, comprising the following steps: a) The separation mixture is introduced into the first distillation column for dealkylation distillation, and the water having a water content of at least greater than 1% by weight, more typically having a water content of greater than 1% to 15% by weight of ethanol, more preferably a water content of 1.5- 15% by weight of ethanol, more preferably ethanol having a water content of 3 to 10% by weight, most preferably ethanol having a water content of 4.5 to 10% by weight, introduced from a side line position not lower than the feeding position of the mixture to be separated a first distillation column, collecting a C ₄ -containing hydrocarbon fraction at the top of the first distillation column, wherein the C ₄ -containing hydrocarbon fraction further comprises ethanol and water; more preferably at least a portion of the condensate flowing out from the top of the first distillation column Or the reflux liquid is separated by oil and water to remove at least a part of the water phase, and then used as a reflux of the first distillation column;

b) a mixture containing ETBE and ethanol taken from the bottom of the first distillation column or taken out sideways (the side is taken out, the removal position of which is located at the side line below the feed position of the mixture to be separated, preferably located The ethanol concentration is essentially the highest position of the tray or below, preferably located in ethanol The degree is substantially the position between the highest tray or the first block - the 15th theoretical plate below, and the mixture containing ETBE and ethanol is taken out from the vapor phase and/or the liquid phase on the side of the first distillation column; Alternatively, the side removal method can also be seen, for example, CN 1127243 A and US 5607557A, and the like, and the water content is at least more than 1% by weight of ethanol, and more usually the water content is more than 1% by weight to 15% by weight of ethanol, preferably It is an ethanol having a water content of 1.5 to 15% by weight, more preferably an ethanol having a water content of 3 to 10% by weight, most preferably an ethanol having a water content of 4.5 to 10% by weight, and is introduced into a distillation-extraction coupling region, wherein The distillation-extraction coupling zone is composed of a second distillation column and an extraction column, and the operating pressure of the second distillation column is lower than the operating pressure of the first distillation column;

c) collecting the ethanol-containing fraction at the bottom of the second distillation column, and feeding the material containing ETBE, ethanol and water obtained at the top of the second distillation column as an extract feed to the extraction column for extraction; more preferably, the second distillation will be carried out At least a portion of the condensate and/or reflux flowing from the top of the column is separated by oil and water to remove at least a portion of the aqueous phase, and then refluxed and/or recycled as a second distillation column as a feed to the second distillation column; preferably, said At least a portion of the extractant of the extraction column is derived from an ethanol-containing washing liquid which is subjected to water washing and alcohol removal of the C ₄ -containing hydrocarbon fraction collected at the top of the first distillation column, and more preferably, firstly collected from the top of the first distillation column. The ethanol-containing washing liquid containing the C ₄ hydrocarbon fraction is washed with water and extracted as an extractant, and then extracted with water as an extracting agent; the ethanol-containing extract is collected at the bottom of the extracting column, and the ethanol can be recycled and recycled (for example) Re-introduced into the distillation-extraction coupling zone), collecting ETBE-containing raffinate at the top of the extraction column;

The technical solution of the device of the invention is as follows:

A device for coupling and separating and co-production of ETBE and ethanol, comprising a first distillation column Cl, a second distillation column C2 and an extraction column C3:

A connecting line 3 is provided between the reaction zone R and the first distillation column C1 so that the mixture to be separated obtained by the etherification reaction enters the first distillation column Cl.

The side of the first distillation column C1 is provided with a connection line 1 for introducing ethanol having a water content of at least more than 1% by weight, wherein the interface position of the line 1 is not lower than the interface position of the line 3.

The top of the first distillation column C1 is provided with a condenser E2 for collecting a C ₄ hydrocarbon fraction, a condensate tank B1, and a line 5.

A heater E3 and a line 4 for collecting the bottom material are disposed at the bottom of the first distillation column C1, and the pipeline 4 is provided with a heat exchanger E4 and a regulating valve D1 for introducing the material obtained at the bottom of the first distillation column C1 to the second distillation column C2.

A connecting line 2 is provided in the second distillation column C2 for introducing ethanol having a water content of at least more than 1% by weight.

A heater E6 and a line 8 for collecting the ethanol-containing fraction are disposed at the bottom of the second distillation column C2. A condenser E5 for collecting overhead materials, a condensate tank B2, and a line 9 are disposed at the top of the second distillation column C2. The material obtained from the top of the second distillation column C2 is sent to the extraction column C3 via line 9.

The extractant enters the extraction column C3 from line 12, and the ethanol-containing extract is collected via line 10 at the bottom of the extraction column C3, and the ETBE-containing raffinate is collected from the top of the extraction column C3 via line 11.

There is also a coupling integrated separation and production of ETBE and ethanol, including a first distillation column Cl, a second distillation column C2 and an extraction column C3:

A heater E3 and a line 4 for collecting the ETBE-containing fraction are disposed at the bottom of the first distillation column C1. The side of the first distillation column C1 is provided with a line 6 connecting the second distillation column C2, and the line 6 is provided with a heat exchanger E4 and a regulating valve D1 for introducing the material taken out from the side of the first distillation column C1 to the second distillation column. C2, wherein the interface position of the pipeline 6 is located below the interface position of the pipeline 3.

The apparatus for preparing ETBE and ethanol is coupled and integrated according to the present invention, and the apparatus further comprises: providing a pump P1 on the line 11, whereby the raffinate obtained at the top of the extracting column C3 is pressurized by the pump P1 and then circulated to The first distillation column CI.

The coupling integrated separation and co-production of ETBE and ethanol according to the present invention further comprises: providing a line 18 at the bottom of the condensate tank B1 for deriving the layered aqueous phase.

The coupling integrated separation and co-production of ETBE and ethanol according to the present invention further comprises: providing a line 16 at the side of the extraction column C3 for introducing a washing liquid containing ethanol.

The coupling integrated separation and co-production of ETBE and ethanol according to the present invention further comprises: providing a connecting line 17 at a side of the first distillation column C1 for introducing a material containing at least ethanol and C ₄ hydrocarbons into the reaction Zone R, wherein the interface location of line 17 is between the interface location of line 3 and the interface location of line 1.

The apparatus for preparing ETBE and ethanol is produced by coupling and integrating in accordance with the present invention, the apparatus further comprising: a reaction section R1 containing a catalyst disposed in an upper portion of the first distillation column C1, wherein the reaction section R1 containing the catalyst is located in the pipeline 17 The interface position is between the interface position of line 1.

According to the method and apparatus for co-production of ETBE and ethanol according to the present invention, the co-production of ETBE and ethanol is carried out by a coupled integrated separation method. The ETBE obtained by the co-production of ETBE and ethanol may contain less than 1% by weight of ethanol, and the resulting ethanol may contain less than 1% by weight of water, even less than 0.5% by weight of water.

According to the method and apparatus of the present invention, there are no stringent requirements for materials entering the debutanizer column (including, for example, ethanol content and/or water content and/or tertiary alcohol content), and at least water content belonging to renewable resources is used. More than 1% by weight of ethanol, more commonly an amount of ethanol having a water content of more than 1% by weight to 15% by weight, and a mixture to be separated mainly containing ETBE, ethanol and unreacted C ₄ hydrocarbon, both of which have azeotropic separation The problem is therefore more difficult to separate directly by the ordinary distillation method, integrated into two groups by heterogeneous azeotrope and/or ternary azeotropy coupled with ETBE, ethanol and water and C ₄ hydrocarbon, ethanol and water. On the one hand, it can directly reduce the energy consumption and cost of separation and purification and ethanol recovery for two groups of azeotrope systems such as ETBE and ethanol, C ₄ hydrocarbons and ethanol, and on the other hand, ethanol with water content of at least 1% by weight, The more common dehydration separation process of water having a water content of more than 1% by weight to 15% by weight, using at least one of two groups of heterogeneous azeotrope and/or ternary azeotrope, or even If one of the separation treatments is carried out, substantially sufficient azeotropic water-containing ethanol required for the self-etherification reaction can be obtained, and substantially no additional energy consumption and cost are required, and even ethanol is facilitated. In the high energy consumption process of concentrated enrichment and dehydration separation close to the azeotrope, it is related to the process and equipment for preparing ETBE, and/or the petrochemical process and equipment which may have more abundant waste heat resources or may be more convenient for heat integration. Coupling In order to achieve multiple coupling integration of process coupling and product coupling, including coupling production of ETBE and ethanol products. In addition, an ethanol feedstock can be provided for the etherification reaction of at least the ethyl tertiary alkyl ether including the preparation of ETBE, and/or an ethanol product which can be used as a gasoline additive can be provided as needed, and it is even advantageous for an appropriate increase or relaxation. The alcohol/olefin ratio of the etherification reaction is such that it is easy to increase the conversion of isobutylene and/or the selectivity of the etherification reaction within a certain range, and thus has an optimized commercial value (function/cost). DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing the method and apparatus for preparing ETBE and ethanol by coupling integrated separation and separation according to the present invention (including material taken out from the bottom of the first distillation column).

Fig. 2 is a schematic flow chart showing the method and apparatus for preparing ETBE and ethanol by coupling integrated separation and separation according to the present invention (including material taken out from the side of the first distillation column).

Where: R (R1 ) reaction zone (reaction zone), C1 first distillation column, C2 - second distillation column, C3 - extraction column, B1-B2 - condensate tank, D1 - regulating valve, E1-E7 - heat exchange , P1 - pump, 1-18 - pipeline number or pipeline material stream number. detailed description

Hereinafter, a method and an apparatus for coupling, integrated, and co-production of ETBE and ethanol according to the present invention will be described in detail with reference to FIG. 1, FIG. 2 and the examples.

A method and a device for coupling and separating and co-production of ETBE and ethanol, comprising the steps of: separating ETBE, ethanol and unreacted C ₄ hydrocarbons obtained by etherification reaction of ethanol and isobutylene in reaction zone R The mixture is passed through line 3 and can be introduced into the first distillation column C1 by heat exchange of the heat exchanger E1 for dealkylation distillation, and the water content is at least more than 1% by weight of ethanol, and more usually the water content is more than 1% by weight to 15% by weight. % ethanol is introduced into the first distillation column C1 via a line 1 from a side line position not lower than the feed position of the mixture to be separated, and a condenser E2 and a condensate tank B1 are disposed at the top of the first distillation column C1, and are collected through the line 5. A C ₄ -containing hydrocarbon fraction, wherein the C ₄ -containing hydrocarbon fraction further contains ethanol and water. More preferably, at least a portion of the condensate or reflux liquid flowing out from the top of the first distillation column C1 is separated by oil and water to remove at least a part of the aqueous phase, and then refluxed as the first distillation column C1. In this way, the azeotropic water-removing ability of the C ₄ hydrocarbon can be more fully utilized in order to be able to separate more of the water in the ethanol from the top of the column, thereby obtaining more even including sufficient for the etherification reaction. Basically remove azeotropic aqueous ethanol (See U.S. Patent No. US 5248836A), in particular for the use of lower levels of isobutylene C ₄ hydrocarbon feedstock to etherification reaction, although the number of available ETBE will be less, but the required amount for the etherification reaction in ethanol It will also be less, and additional economic compensation can be obtained by co-production of azeotropic water-removing capacity of C ₄ hydrocarbons which is more affluent to obtain substantially more azeotropic water-containing ethanol.

among them:

Introduced into the reaction zone via line 13 R isobutylene feed is a mixed C ₄ hydrocarbons containing isobutene, such as steam cracking or catalytic dehydrogenation of butane or isobutene from a mixed C ₄ hydrocarbons, generally containing 8-70 mol% isobutene, It is also possible to have a lower or higher proportion of isobutylene, see US 5248836A.

Typically, ethanol can be introduced directly into reaction zone R, including, for example, the introduction of ethanol from the co-production of the present invention via line 14 to reaction zone R. In a possible preferred embodiment of the present invention, a connecting line 17 may be provided at the side of the first distillation column C1 for introducing a material containing at least ethanol and C ₄ hydrocarbons into the reaction zone R, wherein the pipeline The interface position of 17 is located between the interface position of the pipeline 3 and the interface position of the pipeline 1; or, further comprising a reaction section R1 containing a catalyst disposed at an upper portion of the first distillation column C1, wherein the reaction section R1 containing the catalyst is located The interface position of the line 17 is between the interface position of the line 1.

Specific reaction conditions for the etherification reaction of ethanol and isobutylene in the reaction zone R can be found in, for example, US 5248836A, CN 1990443A, CN1772848A, CN101195560A and the like.

The first distillation column C1 may also generally be a reactive distillation column having a reaction zone R1. The first distillation column C1 is operated at a pressure higher than atmospheric pressure, preferably at a pressure of 5 to 15 bar, and more preferably at a pressure of 7 to 13 bar. The operating temperature of the top of the first distillation column C1 is from 30 ° C to 100 ° C, and the operating temperature of the bottom of the first distillation column C1 is from 70 ° C to 200 ° C.

A heater E3 and a line 4 for collecting the bottom material are disposed at the bottom of the first distillation column C1, and a mixture containing ETBE and ethanol which is collected from the bottom of the first distillation column C1 via line 4 or taken out from the side via line 6 The heat exchanger E4 and the regulating valve D1 are introduced into the distillation-extraction coupling zone, and at the same time, the water content introduced through the pipeline 2 is at least more than 1% by weight of ethanol, and more usually the water content is more than 1% by weight to 15% by weight of ethanol. Introduce a distillation-extraction coupling zone. Wherein the distillation-extraction coupling zone is composed of a second distillation column C2 and an extraction column C3, and the operating pressure of the second distillation column C2 is lower than the operating pressure of the first distillation column C1.

A heater E6 and a line 8 for collecting the ethanol-containing fraction are disposed at the bottom of the second distillation column C2, and a condenser E5, a condensate tank B2, and a line 9 for collecting the top material are disposed at the top of the second distillation column C2. The material obtained from the top of the second distillation column C2 is fed to the extraction column C3 via line 9 and may be fed through a heat exchanger E7. The extractant of the extraction column C3 can usually be water. In some embodiments, the ethanol-containing washing liquid after washing the alcohol-containing C ₄ hydrocarbon fraction collected at the top of the first distillation column C1 can also be used. Preferably, at least a portion of the extractant of the extraction column C3 is derived from an ethanol-containing washing liquid which is subjected to water washing and alcohol removal of the C ₄ -containing hydrocarbon fraction collected at the top of the first distillation column C1 via the line 5, and more preferably, The ethanol-containing washing liquid from the C ₄ hydrocarbon fraction collected from the top of the first distillation column C1 via the line 5 is washed with water as an extractant, and then extracted with water as an extractant via line 12 . At the bottom of the extraction column C3, an ethanol-containing extract is collected via line 10, and the recovered ethanol is recycled (e.g., reintroduced into the distillation-extraction coupling zone via line 15), and ETBE-containing is collected via line 11 at the top of the extraction column C3. Raffinate. Since the content of ethanol in the C ₄ -containing hydrocarbon fraction or its oil phase flowing out from the top of the first distillation column C1 has been significantly lowered, it is usually reduced by about half or more, thereby correspondingly greatly reducing the subsequent water washing. The water consumption of alcohol. The content of the ETBE, ethanol and water-containing material or the oil phase thereof flowing from the top of the second distillation column C2 is also significantly lower than the azeotropic composition of ETBE and ethanol, and is usually reduced by about half. . At the same time, the ethanol content of the ethanol-containing washing liquid is inherently relatively low. Therefore, the above-described method and apparatus including the embodiment can greatly save the consumption of water as the extractant. Moreover, by reducing the amount of ethanol separation and recovery treatment and/or reducing water consumption and/or coupling extraction to increase the ethanol content in the ethanol-containing washing liquid, it is very advantageous to save the energy consumption of the subsequent enrichment recovery of ethanol, and even correspondingly Can achieve energy savings of about half or more.

When a mixture containing ETBE and ethanol is taken out from the side of the first distillation column C1 via line 6, 0-100% of the ETBE-containing raffinate obtained at the top of the extraction column C3 is circulated through line 11 and pressurized by pump P1. The first distillation column C1 is passed, and the ETBE-containing fraction is collected from the bottom of the first distillation column C1 via line 4.

Wherein: as the feed of the second distillation column C2, the content of ETBE, ethanol and water therein may be combined to enable almost all of the water to be substantially under the operating conditions of the second distillation column C2 The form of ternary azeotrope and/or heterogeneous azeotrope is taken from the top of the column. Even a small amount of remaining ETBE can be removed from the top of the column by binary azeotropy of ETBE/water and/or ETBE/ethanol. For example, at an operating pressure of 1 bar, the reference composition of the ternary azeotrope is: about 82.9 wt% ETBE, 11.6 wt% ethanol, and 5.5% wt% water, and the binary azeotrope water content of ETBE/water. For 6% by weight, the binary azeotropic alcohol content of ETBE/ethanol is 21% by weight (for azeotrope data see Lee H. Horsley: Azeotropic

Data - IIL American Chemical Society / Washington, DC 1973, US 5250156A, Pure Appl. Chem., Vol. 71, No. 6, pp. 939-949, 1999., etc.). In fact, since ethanol is often excessive, it is usually necessary to control the amount of ethanol introduced according to the water content of the introduced ethanol, so as to be from the second At the bottom of the distillation column C2, ethanol having a water content is obtained.

As the ethanol having a water content of at least 1% by weight introduced into the second distillation column C2 via the line 2, it is more common to include at least a water content of more than 1% by weight to 15% by weight of the replenished ethanol, preferably The ethanol having a water content of 1.5 to 15% by weight, more preferably 3 to 10% by weight of the added ethanol, most preferably the added ethanol having a water content of 4.5 to 10% by weight, Or the recovered ethanol introduced via line 15 is also included. The total water content is the weight ratio of the ETBE mainly contained in the mixture of ETBE and ethanol introduced into the second distillation column C2 via line 4 or line 6 (i.e., water/ETBE weight ratio), and the suitable ratio is in the range of 0.008. -0.18: 1, a more suitable ratio range is 0.02-0.09: 1, the most suitable ratio range is 0.03-0.08: 1. Or, as the added ethanol introduced into the second distillation column C2, or further including the recovered ethanol introduced, and mainly containing a mixture of ETBE and ethanol, the total water content thereof is introduced into the second distillation column C2 The ratio mainly includes the weight ratio of ETBE in the mixture of ETBE and ethanol (ie, water/ETBE weight ratio), and the suitable ratio ranges from 0.008 to 0.18: 1, and the more suitable ratio ranges from 0.02 to 0.09:1. A suitable ratio range is 0.03-0.08:1.

It may be advantageous to add the molar amount or number of moles of ethanol to the ethanol added to the second distillation column C2, and the mole of ETBE in the mixture mainly comprising ETBE and ethanol introduced to the second distillation column C2. The common ratio of flow rate or number of moles is 0.4-25.9: 1, the appropriate ratio range is 1-25.9: 1, the more suitable ratio range is 1-6.3: 1, the most suitable ratio range is 1-3.5. : 1.

The operating pressure of the second distillation column C2 is 0.5-2 bar (preferably 1-2 bar), the temperature of the top of the second distillation column C2 is 45-80 ° C, and the temperature of the bottom of the second distillation column C2 is 60 -95 ° C, a suitable feed temperature is 10-80 ° C, a more suitable feed temperature is 50-80 ° C, preferably in the vicinity of the second distillation column C2 operating pressure ETBE / ethanol / water A ternary azeotropic and/or heterogeneous azeotropic temperature feed.

The ethanol-containing fraction collected from the bottom of the second distillation column C2 has a water content which is related to the process conditions, and usually has a water content of less than 1% by weight, and may even be less than 0.5% by weight. The ethanol-containing fraction collected from the bottom of the second distillation column C2 has an ethanol content which is related to the process conditions, and its ethanol content is preferably more than 99% by weight.

The condensate and/or reflux liquid condensed from the top of the second distillation column C2 may have a small amount of water phase depending on the process conditions, and may be at least partially separated by oil and water to remove at least a part of the water phase, and then The reflux and/or recycle of the second distillation column C2 as a feed to the second distillation column C2, preferably at least a portion of the condensate or/and reflux is subjected to oil-water separation at 10-60 ° C, more preferably at 10-40 ° C. Operation, the aqueous phase separated by oil-water separation (aqueous solution containing ethanol) can be further processed (not shown), recycled after recovery of ethanol, or with the rest including at least part of the oil phase and / or water phase Condensation The liquid is sent together for extraction treatment.

Thus, the coupling integrated separation and production method of the present invention can also be used for the preparation of ETBE and ethanol for ethanol having a water content of at least more than 1% by weight, more commonly having a water content of more than 1% by weight to 15% by weight of ethanol. Suitable is ethanol having a water content of 1.5 to 15% by weight, more preferably ethanol having a water content of 3 to 10% by weight, most preferably ethanol having a water content of 4.5 to 10% by weight. Ethanol can be used for coupling and separation to remove moisture contained in ethanol. The ethanol-containing fraction thus obtained has an ethanol content which is related to the process conditions, and its ethanol content is preferably more than 99% by weight. Such a method and apparatus and an embodiment thereof can carry out a high-energy process in which ethanol is concentrated and concentrated in a concentration close to the azeotrope, and a petrochemical process which may have a relatively rich waste heat resource or may be more easily thermally integrated. The refinery is coupled and thus may be particularly advantageous.

Generally, the temperature in the column at the ethanol feed position of the ternary azeotrope and/or heterogeneous azeotropic distillation column differs little from the temperature at the top of the column, such as may only have a temperature difference of no more than 4-8 ° C, and the distillation column The temperature of the top may also be as low as about 60-70 °C. Therefore, a possible advantageous manner is: the first distillation column C1 is further provided with an intermediate reboiler (not shown), and the intermediate reboiler is located below the feed position of the water having a water content of at least greater than 1% by weight; And/or, the second distillation column C2 is further provided with an intermediate reboiler located below the feed position of the ethanol having a water content of at least greater than 1% by weight (not shown). In this manner, more low temperature waste heat can be utilized to obtain more substantially free azeotropic aqueous ethanol.

The operating pressure of the extraction column C3 is 1-15 bar (preferably 1-10 bar), and the operating temperature of the extraction column C2 is 5-70 ° C (preferably 10-60 ° C).

The ETBE-containing raffinate collected from the top of the extraction column C3 has an ethanol content which is related to the process conditions, and usually has an ethanol content of less than 1% by weight.

The ETBE-containing raffinate collected from the top of the extraction column C3 is an ETBE containing saturated water. After removing the ethanol, it contains only a trace amount of water at normal temperature. For example, the saturated water content of ETBE at 20 ° C is 0.5 g / 100 g. ETBE, it is generally considered that no further water removal treatment is necessary. Of course, if necessary, any suitable method of removing water can be used, such as drying with water using a silica gel adsorbent. Alternatively, when the material is taken out from the side of the first distillation column C1 for coupling-integration separation, it can be sent back to the first distillation column Cl, so that ETBE which is almost completely free of water can be obtained from the bottom of the first distillation column C1.

Typically, the C ₄ hydrocarbon fraction containing the top of the first distillation column C1 collected also contain small amounts of ethanol azeotrope out. Therefore, in the general process for preparing a tertiary alkyl ether, it is also washed with water to remove alcohol, and a recovery tower is provided to enrich and recover the ethanol, as described in, for example, US Pat. No. 5,447,607. Thus, the recovery tower can be utilized to extract from the extraction The ethanol-containing extract collected at the bottom of column C3 or other aqueous solution containing ethanol is also enriched to recover ethanol and recycled for use, such as recycling to second distillation column C2.

A possible more advantageous manner is to include at least an ethanol-containing extract collected from the bottom of the extraction column C1, and enrich the recovered ethanol in the recovery tower, wherein the operating pressure of the recovery tower is higher than the operating pressure of the second distillation column C2, preferably The operation pressure of the recovery tower is higher than the operating pressure of the second distillation column C2 by 0.5-5 bar, and the overhead steam of the recovery tower is used as the heating steam of the second distillation column C2 bottom heater E6 (not shown) Draw).

One possible preferred way is to: freshly ethanol having at least a partial water content of at least more than 5% by weight, preferably more than 8% by weight, more preferably more than 10% by weight, first concentrated in the recovery column, and then at least as a second distillation Feed of column C2.

The use of thermal coupling can save heating steam generated by at least one of the second distillation column C2 and the recovery tower, and is advantageous for adjusting the separation load of the two towers according to the balance of the heat load, thereby facilitating energy saving and separation of the two towers. Combination optimization adjustment.

One possible more advantageous way is to use at least a portion of the ethanol-containing fraction collected from the bottom of the second distillation column C2 as the feed to the reaction zone R. In this manner, it may be necessary or only necessary to provide the reaction zone R with substantially azeotropically dehydrated ethanol for start-up at the start of the apparatus.

One possible preferred way is that the ethanol feed to reaction zone R is derived from the ethanol-containing fraction collected from the bottom of distillation column C2.

The invention is further illustrated by the following examples.

Example:

The first distillation column C1 is composed of a perforated tray having 80 trays, a stainless steel tower having a plate length of 50 mm and an inner diameter of 100 mm. The second distillation column C2 is composed of a perforated tray having 70 trays, a glass column having a plate length of 50 mm and an inner diameter of 50 mm. The extraction column C3 consists of a stainless steel column with 24 perforated plates with a plate spacing of 100 mm and an inner diameter of 30 mm. The three towers are thermally insulated to avoid heat loss, and the trays of the three towers are numbered starting from top to bottom.

Process Flow Referring to Figure 1, a material obtained by etherification reaction of ethanol and isobutylene in the reaction zone R is used as a mixture to be separated (line 3), and is fed from the 40th tray of the first distillation column C1 at a feed temperature of 80 ° C. Ethanol (line 1) having a water content of 5% by weight was fed from the 12th tray of the first distillation column C1 at a feed temperature of 65 °C. The operating pressure at the top of the column is 8 bar, the reflux ratio is 0.75: 1, the temperature at the top of the column is 6VC, and the C ₄ hydrocarbon fraction (line 5) is collected from the top of the first distillation column C1, wherein the collected C ₄ -containing hydrocarbon stream is collected. The mixture containing ETBE and ethanol collected from the bottom of the first distillation column CI (line 4) is exchanged to 67 ° C via heat exchanger E1 and regulating valve D1, and mixed with ethanol (line 2) containing azeotropic water. It was fed from the 40th tray of the second distillation column C2. The operating pressure of the top of the second distillation column C2 is 1 bar, the temperature at the top of the column is 64 ° C, the temperature at the bottom of the column is 79 ° C, and the reflux ratio is 3 : 1 (the temperature of the condensate is about 30 ° C, containing about 2 The wt% aqueous phase) collects the ethanol-containing fraction from the bottom of the column (line 8). After the overhead effluent material (line 9) is exchanged to 30 ° C via heat exchanger E7, the 24th tray of extraction column C3 is fed, and 20 ° C water (line 12) is taken from extraction column C3. The first tray was fed, and a 20 ° C ethanol-containing washing liquid (line 16) was fed from the 18th tray of the extraction column C3, and the extraction column C3 was operated at a pressure of 1 bar. The ETBE-containing raffinate is collected from the top of the extraction column C3 (line 11), and the ethanol-containing extract collected from the bottom of the extraction column C3 (line 10) can be further recycled and recycled. The material balance table of each pipeline material stream including the mixture to be separated and the azeotropic water-containing ethanol is shown in Table 1.

Table 1: Material balance table of Example 1

Composition

Line i line 2 line 3 line 4 line 5 line 8 line 9 line 10 line 11 line 12 line 16 wt%

c ₄ 0 0 59.5 0.1 98.6 0 0.1 0 0.1 0 0

H ₂ 0 5.0 5.0 0 0 0.6 0.2 4.0 82.4 0.8 100.0 97.0

EtOH 95.0 95.0 5.9 24.5 0.8 99.1 12.8 15.9 0.2 0 3.0

E2BE 0 0 0.2 0.3 0 0 0.4 0 0.4 0 0

ETBE 0 0 33.9 74.2 0 0 82.4 1.7 98.0 0 0

TBA 0 0 0.3 0.6 0 0.7 0 0 0 0 0 c ₅₊ 0 0 0.1 0.2 0 0 0.3 0 0.3 0 0

DEE 0 0 0.1 0.1 0 0 0.1 0 0.2 0 0 Flow,

184 1019 3000 1373 1811 1156 1235 1075 1020 360 500 g / h

Claims

Claim

A method for coupling and separating and co-production of ETBE and ethanol, which comprises using a mixture to be separated of ETBE, ethanol and unreacted C ₄ hydrocarbon obtained by etherification reaction of ethanol and isobutylene, the method comprising :

c) collecting the ethanol-containing fraction at the bottom of the second distillation column, feeding the material containing ETBE, ethanol and water obtained at the top of the second distillation column as an extraction feed to the extraction column for extraction, and collecting ethanol at the bottom of the extraction column Extracting the ETBE-containing raffinate at the top of the extraction column;

2. The method according to claim 1, wherein when the mixture containing ETBE and ethanol is taken out from the side of the first distillation column, the position of the side taken-out material is located below the feed position of the mixture to be separated, and ethanol The concentration is substantially the highest position of the tray or below, and the mixture containing ETBE and ethanol is withdrawn from the vapor phase and/or liquid phase on the side of the first distillation column.

3. The method according to claim 1, wherein at least a portion of the condensate or reflux liquid flowing out from the top of the first distillation column is separated by oil and water to remove at least a part of the aqueous phase, and then used as a reflux of the first distillation column; / or, at least part of the condensate and / or reflux liquid flowing from the top of the second distillation column is separated by oil and water to remove at least part of the aqueous phase, and then as a reflux and / or circulation of the second distillation column as the second distillation column material.

4. The method according to claim 1, wherein the water content introduced into the second distillation column is at least greater than 1% by weight of ethanol, and at least comprises a water content of more than 1% by weight to 15% by weight of the added Ethanol, or also included in recycled ethanol, where:

The supplemented ethanol or the recovered ethanol, the total water content and the weight ratio of the ETBE in the mixture containing ETBE and ethanol is 0.008-0.18: 1; or, the supplemented ethanol or Also included is the recovered ethanol, and the mixture comprising ETBE and ethanol, the total water content and the weight ratio of the ETBE in the mixture containing ETBE to ethanol is from 0.008 to 0.18:1; or, the addition The ratio of the molar flow rate or number of moles of ethanol contained in the ethanol to the molar flow rate or number of moles of ETBE in the mixture containing ETBE and ethanol is 1-25.9:1.

5. The method according to claim 1, characterized in that at least part of the extracting agent from the extraction column of C ₄ hydrocarbons containing top of the first distillation column water collected after the washing solution containing ethanol except the alcohol fraction.

The method according to any one of claims 1 to 5, wherein the ethanol-containing fraction collected at least partially from the bottom of the second distillation column is introduced into the reaction zone.

The method according to any one of claims 1 to 5, characterized in that at least the ethanol-containing extract collected from the bottom of the extraction column is concentrated in the recovery tower to recover ethanol, wherein the operating pressure of the recovery tower It is higher than the operating pressure of the second distillation column, and the overhead vapor of the recovery column is used as the heating steam of the bottom distillation heater of the second distillation column.

8. Process according to claim 7, characterized in that at least part of the fresh ethanol having a water content of at least more than 5% by weight is first concentrated in the recovery column and then at least as a feed to the second distillation column.

An integrated cogeneration process for separating ethanol and ETBE preparation coupling, the method comprising: containing a mixture of isobutene and C ₄ hydrocarbons containing at least the material with ethanol and C ₄ hydrocarbons withdrawn from the first distillation column side lines in a reaction zone Etherification reaction, and the mixture to be separated of ETBE, ethanol and unreacted C ₄ hydrocarbon obtained by etherification reaction, and the material containing at least ethanol and C ₄ hydrocarbon taken out from the side of the first distillation column Introducing a first distillation column below the position, performing coupling-integration separation using the method according to any one of claims 1-8, thereby collecting a C ₄ -containing hydrocarbon fraction at the top of the first distillation column, in the second distillation column Collecting an ethanol-containing fraction at the bottom, collecting an ethanol-containing extract at the bottom of the extraction column, collecting an ETBE-containing raffinate at the top of the extraction column, and/or collecting an ETBE-containing fraction at the bottom of the first distillation column, wherein The material taken out of the side of the first distillation column containing at least ethanol and C ₄ hydrocarbons is taken at a position below which the ethanol having a water content of at least greater than 1% by weight is introduced into the feed position of the first distillation column.

10. The method according to claim 9, wherein a reaction section containing a catalyst is disposed at an upper portion of the first distillation column, wherein the reaction section containing the catalyst is introduced to introduce ethanol having a water content of at least greater than 1% by weight. a feed position to the first distillation column and at least a portion taken from a side of the first distillation column Between the removal position of the material of the alcohol and the C ₄ hydrocarbon.

11. A coupled integrated separation product for the preparation of ETBE and ethanol, comprising a first distillation column (Cl), a second distillation column (C2) and an extraction column (C3), characterized in that:

A connecting line (3) is disposed between the reaction zone (R) and the first distillation column (C1), so that the mixture to be separated obtained by the etherification reaction enters the first distillation column (C1);

The side of the first distillation column (C1) is provided with a connecting line (1) for introducing ethanol having a water content of at least more than 1% by weight, wherein the interface position of the line (1) is not lower than the interface position of the line (3);

a condenser (E2), a condensate tank (B1), and a line (5) for collecting a C ₄ hydrocarbon fraction are disposed at the top of the first distillation column (C1);

A heater (E3) and a line (4) for collecting the bottom material are disposed at the bottom of the first distillation column (C1), and a heat exchanger (E4) and a regulating valve (D1) are disposed on the line (4) for Introducing the material obtained at the bottom of the first distillation column (C1) to the second distillation column (C2);

Providing a connecting line (2) in the second distillation column (C2) for introducing ethanol having a water content of at least more than 1% by weight;

A heater (E6) and a pipe line (8) for collecting the ethanol-containing fraction are disposed at the bottom of the second distillation column (C2);

The top of the second distillation column (C2) is provided with a condenser (E5) for collecting the top material, a condensate tank (B2) and a line (9); the material obtained from the top of the second distillation column (C2) is passed through the line (9) It is sent to the extraction column (C3); the extractant enters the extraction column (C3) from the line (12), and the ethanol-containing extract is collected at the bottom of the extraction column (C3) via the line (10), from the top of the extraction column (C3). Line (11) collects the raffinate containing ETBE.

12. A coupled integrated separation product for the preparation of ETBE and ethanol, comprising a first distillation column (Cl), a second distillation column (C2) and an extraction column (C3), characterized in that:

A heater (E3) for collecting the ETBE-containing fraction is disposed at the bottom of the first distillation column (C1) and Pipeline (4);

The side of the first distillation column (C1) is provided with a line (6) connected to the second distillation column (C2), and a heat exchanger (E4) and a regulating valve (Dl) are disposed on the line (6) for the first distillation The side (C1) side take-out material is introduced into the second distillation column (C2), wherein the interface position of the pipeline (6) is located below the interface position of the pipeline (3);

13. The apparatus according to claim 12, further comprising: providing a pump (P1) on the pipeline (11), whereby the raffinate obtained at the top of the extraction tower (C3) is pumped (P1) After pressurization, it is recycled to the first distillation column (Cl).

14. Apparatus according to any one of claims 11-13, further comprising: a line (18) at the bottom of the condensate tank (B1) for deriving the layered aqueous phase.

The apparatus according to any one of claims 11 to 13, characterized in that the apparatus further comprises: a line (16) provided on the side of the extraction column (C3) for introducing a washing liquid containing ethanol.