WO2022011871A1

WO2022011871A1 - Micro-interface reaction system and method of coal-to-ethanol

Info

Publication number: WO2022011871A1
Application number: PCT/CN2020/122730
Authority: WO
Inventors: 张志炳; 周政; 张锋; 李磊; 孟为民; 王宝荣; 杨高东; 罗华勋; 杨国强; 田洪舟; 曹宇
Original assignee: 南京延长反应技术研究院有限公司
Priority date: 2020-07-16
Filing date: 2020-10-22
Publication date: 2022-01-20
Also published as: CN111777491A

Abstract

The present invention relates to a reaction system and method for coal-to-ethanol. The reaction system comprises a methanol-to-dimethyl ether reaction unit and a dimethyl ether-to-ethanol reaction unit which are connected in sequence, wherein the methanol is prepared from the gasification of coal. The methanol-to-dimethyl ether reaction unit includes a dimethyl ether reactor. Methanol is introduced into the dimethyl ether reactor for a vapor-phase catalytic dehydration reaction. The dimethyl ether-to-ethanol reaction unit includes a carbonylation reactor, and the outer side of the carbonylation reactor is provided with a first micro-interface generator. In the first micro-interface generator, dimethyl ether separated from the rectification tower by rectification is introduced, and at the same time carbon monoxide is introduced, and same is then dispersed and crushed by means of the first micro-interface generator and then enters the carbonylation reactor for reaction. The micro-interface reaction system reduces the energy consumption, reduces the reaction temperature, improves the utilization rate of the raw materials, and also effectively improves the productivity.

Description

Micro-interface reaction system and method for producing ethanol from coal

technical field

The invention relates to the field of coal-to-ethanol, in particular to a micro-interface reaction system and method for coal-to-ethanol.

Background technique

Worldwide, the production routes of ethanol include grain fermentation routes, petrochemical routes and carbon-one chemical routes such as coal and natural gas. Grain fermentation routes are widely used internationally, and large-scale ethanol production enterprises mostly use grain fermentation processes. Affected by the "food crisis", China has stopped approving new corn fuel ethanol projects. The cellulosic fuel ethanol project fermented with cassava and corn stover has poor economic benefits due to its high production cost, excessive dependence on state subsidies, and imperfect production technology. The petrochemical route uses ethylene as raw material to produce fuel ethanol through ethylene hydration. my country relies heavily on imports of oil, and the price of ethylene is often higher than that of ethanol, which restricts the application and promotion of this method in my country.

Coal, natural gas and other carbon-to-chemical routes use coal or natural gas as raw materials to first obtain synthesis gas and methanol, and then obtain ethanol by dimethyl ether method or acetic acid method. This method uses coal as raw material, plus my country's coal resources It is rich, so it is the most widely used in my country now. However, this method has a series of problems such as high reaction pressure, high temperature, high energy consumption, low utilization rate of raw materials, and low production capacity.

In view of this, the present invention is proposed.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide a micro-interface reaction system for producing ethanol from coal. The micro-interface reaction system reduces the energy consumption, reduces the reaction temperature, and improves the The reaction yield is improved, especially the utilization rate of the reaction gas phase is improved, and the production capacity is effectively improved, thereby improving the quality and yield of the product, and also saves equipment costs and saves the floor space of the equipment.

The second object of the present invention is to provide a reaction method for producing ethanol from coal using the above-mentioned micro-interface reaction system, which fully disperses and crushes the reaction raw materials, improves the mass transfer efficiency of the reaction, and improves the conversion rate of the reaction raw materials , but also correspondingly improve the product yield.

In order to realize the above-mentioned purpose of the present invention, the following technical solutions are specially adopted:

The invention provides a coal-to-ethanol micro-interface reaction system, comprising: a methanol-to-dimethyl ether reaction unit and a dimethyl ether-to-ethanol reaction unit connected in sequence, wherein the methanol is prepared by coal gasification;

The methanol-to-dimethyl ether reaction unit comprises: a dimethyl ether reactor; methanol is passed into the dimethyl ether reactor for gas-phase catalytic dehydration reaction, and the reacted product enters a first rectifying tower for dimethyl ether purification Rectification, part of the gas phase condensation after the rectification is returned to the first rectifying tower, and part of the dimethyl ether reactor is returned to the dimethyl ether reactor for re-reaction; ;

The dimethyl ether-to-ethanol reaction unit includes: a carbonylation reactor, and a first micro-interface generator is arranged on the outside of the carbonylation reactor, and the first micro-interface generator is connected to the first micro-interface generator. The dimethyl ether separated by rectification in the distillation column, and carbon monoxide is introduced at the same time. After being dispersed and broken by the first micro-interface generator, it enters the carbonylation reactor for reaction, and the carbonylation reactor is connected to the second micro-interface. The generator is used to pass the carbonylation product into the second micro-interface generator, and the second micro-interface generator is fed with hydrogen at the same time, and enters the hydrogenation reaction after being dispersed and broken by the second micro-interface generator The reactor is used to carry out the hydrogenation reaction of methyl acetate, and the reaction product after the hydrogenation reaction is separated from methanol and ethanol through the second rectification column to obtain ethanol.

In the micro-interface reaction system for producing ethanol from coal of the present invention, a micro-interface generator is correspondingly arranged before the carbonylation reactor and the hydrogenation reactor to disperse and break the incoming gas phase into micro-bubbles, thereby improving the mass transfer effect , the main function of introducing the liquid phase inside the micro-interface generator is to cooperate with the dispersion and crushing of the gas, which is equivalent to the role of the medium.

In addition, in the micro-interface reaction system of the present invention, the reason why it is necessary to install a micro-interface generator before both the carbonylation reactor and the hydrogenation reactor is because the reactions carried out in the two reactors are both gas-liquid two-phase The micro-interface generator set can just play the role of dispersing and breaking the gas phase, and because of the setting of the micro-interface generator, dimethyl ether does not need to be gasified first, and can be directly passed into the micro-interface generator and mixed with carbon monoxide to disperse and fragment. , simplifies the operation steps, it can be seen that although the structure of the micro-interface generator itself already belongs to the prior art, the setting position of the micro-interface generator is obtained through practical design, and needs to be designed according to the different characteristics of different reactions. .

Preferably, the number of the first micro-interface generators and the second micro-interface generators is not unique. In order to increase the mass transfer effect, the number of settings can also be increased accordingly, and the settings are preferably arranged in order from top to bottom. , each micro-interface generator is preferably in a parallel relationship.

The above-mentioned first micro-interface generator and second micro-interface generator are both pneumatic, and the mass transfer effect is improved by passing the gas phase into the micro-interface generator and then directly contacting the liquid phase and then breaking into micro-bubbles.

Of course, in addition to arranging the micro-interface generator in the reactor, the micro-interface generator can also be correspondingly arranged inside the reactor, but the best way is to set the micro-interface generator before the reactor, And it must be equipped with a micro-interface generator before the carbonylation reactor and the hydrogenation reactor, because this ensures that the pressure does not need to be too high during the reaction process, and the raw materials do not need to be gasified, which is more conducive to centralized control and improves For the safety of equipment operation, if one of the micro-interface generators is not installed, the controllability of the material pressure in the whole process will be reduced, the pressure will vary, and the effect of reducing energy consumption will not be fully achieved.

Those skilled in the art can understand that the micro-interface generator used in the present invention has been embodied in the inventor's prior patents, such as application numbers CN201610641119. Patents of CN205833127U and CN207581700U. In the previous patent CN201610641119.6, the specific product structure and working principle of the micro-bubble generator (that is, the micro-interface generator) were introduced in detail. There is a cavity, the body is provided with an inlet communicating with the cavity, the opposite first and second ends of the cavity are open, wherein the cross-sectional area of the cavity is from the middle of the cavity to the first and second ends of the cavity. The second end is reduced; the secondary crushing piece is arranged at at least one of the first end and the second end of the cavity, a part of the secondary crushing piece is arranged in the cavity, and both ends of the secondary crushing piece and the cavity are open An annular channel is formed between the through holes of the micro-bubble generator. The micro-bubble generator also includes an air inlet pipe and a liquid inlet pipe." From the specific structure disclosed in the application document, we can know that its specific working principle is: the liquid enters the micron tangentially through the liquid inlet pipe. In the bubble generator, ultra-high-speed rotation and cutting of the gas make the gas bubbles break into micro-bubbles at the micron level, thereby increasing the mass transfer area between the liquid phase and the gas phase, and the micro-bubble generator in this patent belongs to the pneumatic micro-interface generation. device.

In addition, the previous patent 201610641251.7 records that the primary bubble breaker has a circulating liquid inlet, a circulating gas inlet and a gas-liquid mixture outlet, and the secondary bubble breaker communicates the feed port with the gas-liquid mixture outlet, indicating that the bubble breaker is both It needs to be mixed with gas and liquid. In addition, it can be seen from the following drawings that the primary bubble breaker mainly uses circulating liquid as power, so in fact, the primary bubble breaker belongs to the hydraulic micro-interface generator, and the secondary bubble breaker is a gas-liquid breaker. The mixture is simultaneously fed into the elliptical rotating ball for rotation, so that the bubbles are broken during the rotation, so the secondary bubble breaker is actually a gas-liquid linkage type micro-interface generator. In fact, both hydraulic micro-interface generators and gas-liquid linkage micro-interface generators belong to a specific form of micro-interface generators. However, the micro-interface generators used in the present invention are not limited to the above-mentioned forms. , the specific structure of the bubble breaker described in the prior patent is only one of the forms that the micro-interface generator of the present invention can take.

In addition, the previous patent 201710766435.0 recorded that "the principle of the bubble breaker is to achieve high-speed jets to achieve gas collision", and also stated that it can be used in micro-interface enhanced reactors to verify the relationship between the bubble breaker and the micro-interface generator. and the prior patent CN106187660 also has related records for the specific structure of the bubble breaker, see the specific description in paragraphs [0031]-[0041], and the accompanying drawings, which are related to the bubble breaker S-2 The specific working principle of the bubble breaker is explained in detail. The top of the bubble breaker is the liquid phase inlet, and the side is the gas phase inlet. The liquid phase entering from the top provides the entrainment power, so as to achieve the effect of crushing into ultra-fine bubbles, which can also be seen in the accompanying drawings. The bubble breaker has a conical structure, and the diameter of the upper part is larger than that of the lower part, so that the liquid phase can provide better entrainment power.

Since the micro-interface generator was just developed in the early stage of the previous patent application, it was named as micro-bubble generator (CN201610641119.6), bubble breaker (201710766435.0), etc., and later changed its name to micro-interface generator with continuous technological improvement. The micro-interface generator in the present invention is equivalent to the previous micro-bubble generator, bubble breaker, etc., but the names are different.

To sum up, the micro-interface generator of the present invention belongs to the prior art, although some bubble breakers belong to the type of pneumatic bubble breakers, some belong to the type of hydraulic bubble breakers, and some belong to the type of gas bubble breakers. The type of liquid-linked bubble breaker, but the difference between the types is mainly selected according to the specific working conditions. In addition, the connection between the micro-interface generator and the reactor and other equipment, including the connection structure and connection position, depends on the micro-interface generator. It depends on the structure of the interface generator, which is not limited.

The micro-interface reaction system of the present invention includes two units: a methanol-to-dimethyl ether reaction unit and a dimethyl ether-to-ethanol reaction unit.

Among them, the equipment mainly included in the methanol to dimethyl ether reaction unit is: a dimethyl ether reactor and a first rectification tower.

Methanol is firstly subjected to gas-phase catalytic dehydration reaction in a dimethyl ether reactor to generate dimethyl ether. The reaction temperature is 250 to 270 ° C and the pressure is 1.2 MPa. The catalyst is generally selected from molecular sieve, such as ZSM molecular sieve, aluminum phosphate or γ- Al ₂ O ₃ . The dehydration of methanol to form dimethyl ether is an exothermic reaction, and the temperature of the product gas at the outlet of the reactor is 320°C to 330°C. The main reaction products are dimethyl ether and water, and the side reaction products are carbon oxides, methane and hydrocarbons.

Preferably, the methanol-to-dimethyl ether reaction unit includes a heat exchanger, and the heat exchanger is used for heat exchange between the raw methanol and the gas-phase catalytic dehydration reaction product.

Preferably, the heat exchanger is arranged between the dimethyl ether reactor and the first rectification column, and a preheater is also arranged between the heat exchanger and the dimethyl ether reactor . It is precisely because methanol dehydration to prepare dimethyl ether is an exothermic reaction, so a preheater and a heat exchanger are set up accordingly.

After heat exchange, the reaction product enters the first rectifying tower for purification and rectification, and then a relatively pure dimethyl ether product can be formed, which can be used for the subsequent synthesis of ethanol.

The main function of the first rectifying tower is to purify the dimethyl ether product. After the gas phase methanol recovered at the top of the first rectifying tower is liquefied by the condenser at the top of the tower, part of it is returned to the first rectifying tower, and the other part is returned to the dimethyl ether reaction. The device is reused as the reaction raw material. Most of the materials coming out from the bottom of the first rectifying tower are dimethyl ether and a small amount of methanol, which can also be directly extracted for simple separation, and the separated methanol can be directly used as the reaction raw material of the dimethyl ether reactor.

Preferably, a extraction mechanism for side-line extraction of dimethyl ether is provided on the first rectifying tower, and the extraction mechanism is connected with the first micro-interface generator. The main product of the first rectifying tower is extracted by the side-line extraction mechanism. After the side-line extraction, the dimethyl ether product is transported to the first micro-interface generator for the subsequent ethanol synthesis process.

The equipment mainly included in the dimethyl ether-to-ethanol reaction unit of the present invention is a carbonylation reactor, a separation column, a hydrogenation reactor and a second rectification column.

The type of the carbonylation reactor for carrying out the carbonylation reaction is preferably a fixed bed reactor, and three layers of fixed trays are arranged inside, and a carbonylation reaction catalyst is arranged on each layer of the fixed tray, and the carbonylation reactor is provided with a carbonylation reaction catalyst. Several reaction mixture inlets are respectively arranged at the top of the carbonylation reactor and between adjacent fixed trays.

The dimethyl ether product from the methanol-to-dimethyl ether reaction unit does not need to be gasified, and is directly fed into the first micro-interface generator. At the same time, carbon monoxide is also fed into the first micro-interface generator. Carbon monoxide is in the liquid phase. After being crushed into microbubbles under the action of dimethyl ether, it enters the carbonylation reactor for carbonylation reaction. In order to improve the reaction effect, the mixture inlets on the carbonylation reactor are respectively arranged between the adjacent fixed beds on the side walls. room and top.

Preferably, a separation column is arranged between the carbonylation reactor and the second micro-interface generator for removing gas-phase impurities in the carbonylation product.

Preferably, the top of the separation tower is provided with a separation tank, the gas phase separated by the separation tank goes to the first micro-interface generator, and the liquid phase returns to the separation tower for re-stripping separation.

Carbon monoxide and dimethyl ether undergo a carbonylation reaction under the action of a catalyst to obtain a carbonylation product. The main component of the carbonylation product is methyl acetate and some unreacted dimethyl ether. After stripping through a separation tower, the separation The top of the tower is mainly unreacted dimethyl ether, which can be directly returned to the first micro-interface generator as the reaction feed for carbonylation through the separation tank set at the top of the separation tower, and the liquid phase from the bottom of the separation tank is directly returned to the separation tank. In the column, stripping separation and purification are carried out again.

Preferably, a methyl acetate outlet is provided at the bottom of the separation tower, and the methyl acetate outlet is connected with the second micro-interface generator through a pipeline.

The material coming out from the bottom of the separation tower is mainly methyl acetate, which is transported into the second micro-interface generator through a pump. In order to improve the effect of the second micro-interface generator, methyl acetate is preheated by a preheater before into the second micro-interface generator. Hydrogen is simultaneously introduced into the second micro-interface generator, and the hydrogen is pulverized into micro-bubbles under the action of liquid methyl acetate, and then enters the hydrogenation reactor for hydrogenation reaction.

Preferably, the type of the hydrogenation reactor for the hydrogenation reaction is a fixed bed reactor, the catalyst in the fixed bed reactor is fixed on the bed layer, and the catalyst for the hydrogenation reaction is generally a nickel-based catalyst, preferably the catalyst can be a supported catalyst Nickel-based catalysts of type 1, or nickel-based catalysts modified with alkaline earth metal oxides or rare earth metal oxides are more preferable.

Methyl acetate generates methanol and ethanol after hydrogenation reaction, and then enters into the second rectifying tower for ethanol refining. The operating pressure at the top of the second rectifying tower is about 0.03 MPa, and the vapor at the top of the tower is condensed to 61.7 ° C, and the condensation Part of the liquid phase (methanol) after coming down is returned to the second rectifying tower, and part is sent to the methanol-to-dimethyl ether reaction unit, which is used as a reaction raw material to prepare dimethyl ether.

Preferably, a methanol outlet is provided at the top of the second rectification column, and the methanol outlet is returned to the dimethyl ether reactor through a pipeline to be used as methanol raw material, and a product recovery device is arranged at the bottom of the second rectification column. Exported for extraction of product ethanol.

After the material from the methanol outlet is condensed by the overhead condenser, a part is returned to the second rectification tower, and the other part is communicated with the dimethyl ether reactor through a pipeline to reuse methanol as a raw material.

The product extraction port set at the bottom of the second rectifying tower is used to extract refined ethanol, the temperature is about 101 ℃, the refined ethanol of the extraction port is cooled to 40 ℃ in an ethanol cooler, and then pumped to ethanol through an ethanol buffer tank In the product tank area, the ethanol substandard product tank is set up in the intermediate tank area, which is used for start-up or abnormal production. During the process of ethanol refining in the second rectification tower, a small amount of rectification waste liquid will be produced at the bottom of the tower, the main component of which is acetic acid, which will be sent to the heavy component tank for storage after cooling to room temperature.

The present invention also provides a micro-interface reaction method for producing ethanol from coal, comprising:

The raw material methanol is subjected to gas-phase catalytic dehydration and rectification to obtain dimethyl ether;

After the dimethyl ether and carbon monoxide are mixed, dispersed and crushed, carbonylation reaction is carried out to obtain a carbonylation reaction product;

After the carbonylation reaction product is mixed, dispersed and crushed with hydrogen, and subjected to hydrogenation reaction, ethanol is obtained by rectification.

Preferably, the pressure of the carbonylation reaction is 2.5-3.0 MPa, and the temperature of the carbonylation reaction is 200-230°C.

Preferably, the pressure of the hydrogenation reaction is 2.5-3.0MPa, and the temperature of the hydrogenation reaction is 200-210°C.

In the prior art, the temperature of the dimethyl ether carbonylation reaction is selected at 240-260 ° C, the pressure is selected as 5.0 MPa, the temperature of the hydrogenation reaction is selected at 230-260 ° C, and the pressure is selected at 5.0 MPa, although increasing the temperature can significantly increase the temperature. The reaction activity of the catalyst and the selectivity of the product, but the reaction temperature is too high will accelerate the deactivation of the catalyst; the higher reaction pressure is conducive to the carbonylation reaction and promote the conversion of dimethyl ether, but the reaction pressure is too high will lead to raw materials or products. Therefore, by adopting the reaction method of the present invention, not only the reaction temperature and reaction pressure are appropriately reduced to ensure the activity of the catalyst, but also the energy consumption is reduced, and the reaction effect, the yield and the conversion of the raw materials are also guaranteed. rate remains high.

The ethanol obtained by adopting the coal-to-ethanol reaction of the present invention has high yield and high purity, and the purity can reach 99.9%.

The coal-to-ethanol reaction method of the present invention has low reaction temperature, greatly reduced pressure and high liquid hourly space velocity, which is equivalent to increasing production capacity and increasing product yield.

Compared with the prior art, the beneficial effects of the present invention are:

(1) the micro-interface reaction system of coal-to-ethanol of the present invention reduces the energy consumption, reduces the reaction temperature, and improves the reaction yield by combining the carbonylation reactor, the hydrogenation reactor and the micro-interface generator, Improve the utilization rate of raw materials;

(2) The micro-interface reaction system of coal-to-ethanol of the present invention is most advantageous for simplifying the operation steps and reducing the energy consumption of the whole process by setting the micro-interface generator at a specific position;

(3) The reaction method of coal-to-ethanol of the present invention has low reaction temperature, greatly reduced pressure and high liquid hourly space velocity, which is equivalent to improving the production capacity, and the ethanol obtained by the reaction has high yield and high purity, and the product purity can reach 99.9%.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating preferred embodiments only and are not to be considered limiting of the invention. Also, the same components are denoted by the same reference numerals throughout the drawings. In the attached image:

FIG. 1 is a schematic structural diagram of a micro-interface reaction system for coal-to-ethanol provided by an embodiment of the present invention.

Description of drawings:

10-dimethyl ether reactor; 20-preheater;

30-heat exchanger; 40-first distillation column;

401- tower top condenser; 402- tower kettle reboiler;

50-the first micro-interface generator; 60-CO storage tank;

70-carbonylation reactor; 80-separation tower;

90-second micro-interface generator; 100-hydrogen storage tank;

110-hydrogenation reactor; 120-second distillation column;

1201-Methanol export; 1202-Product extraction and export;

701-fixed tray; 702-mixture import;

801-Separation tank; 802-Methyl acetate outlet.

detailed description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments, It is only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first", "second", and "third" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In order to illustrate the technical solutions of the present invention more clearly, the following descriptions are given in the form of specific embodiments.

Example

Referring to FIG. 1, it is a schematic diagram of the specific structure of the micro-interface reaction system of coal-to-ethanol according to the embodiment of the present invention. The micro-interface reaction system includes two reaction units: a methanol-to-dimethyl ether reaction unit and a dimethyl ether-to-ethanol reaction unit. unit.

Wherein, the dimethyl ether reaction unit includes: a dimethyl ether reactor 10, a first rectification column 40, the raw methanol goes to the dimethyl ether reactor 10, and after the gas-phase catalytic dehydration reaction is performed, the reaction product enters the first rectification column 40 carry out dimethyl ether purification, the tower top gas phase (mainly a small amount of gas-phase dimethyl ether and methanol etc.) after the rectification is condensed and partly returns to the first rectifying tower, and part returns to the dimethyl ether reactor 10 for re-reaction, rectifying The latter dimethyl ether is directly drawn on the side line and sent to the dimethyl ether-to-ethanol reaction unit.

The top of the first rectifying column 40 is provided with a column top condenser 401. After the gas phase at the top of the column passes through the column top condenser 401, a part returns to the first rectifying column 40, and the other part goes out from the column top condenser 401 to the washing column. 140. The tower bottom of the first rectifying tower 40 is provided with a tower kettle reboiler 402, and under the action of the tower kettle reboiler 402, the product (mainly liquid-phase dimethyl ether) flowing out of the tower kettle carries out a simple subsequent purification operation It is also possible to return to the dimethyl ether reactor 10 as a reaction raw material.

Each of the first rectifying towers 40 is provided with a side-line extraction mechanism for extracting the product dimethyl ether, and the extraction mechanism is connected with the first micro-interface generator for subsequent reaction synthesis of ethanol.

Between the dimethyl ether reactor 10 and the first rectification tower 40, a heat exchanger 30 for exchanging heat between the raw methanol and the gas-phase catalytic dehydration reaction product is provided, and at the same time, the heat exchanger 30 and the dimethyl ether reactor 10 are provided with a heat exchanger 30. A preheater 20 is also arranged therebetween for preheating the raw materials entering the dimethyl ether reactor 10 , so as to improve the reaction efficiency of the dimethyl ether reactor 10 .

The dimethyl ether-to-ethanol reaction unit includes: a carbonylation reactor 70 , a first micro-interface generator 50 , a separation column 80 , a second micro-interface generator 90 , a hydrogenation reactor 110 , and a second rectification column 120 .

The side-line extraction mechanism set on the first rectifying tower 40 for the extraction of dimethyl ether products goes to the first micro-interface generator 50, and also passes into the first micro-interface generator 50, and CO is also introduced into the first micro-interface generator 50, and carbon monoxide is obtained from The carbon monoxide transported from the CO storage tank 60 is mixed with dimethyl ether in the first micro-interface generator 50 and then dispersed and crushed, and then enters the carbonylation reactor 70 for carbonylation reaction. The main components of the carbonylation reaction product are: Methyl acetate, and some unreacted dimethyl ether, go to the separation tower 80 from the bottom of the carbonylation reactor 70. The type of the carbonylation reactor 70 is a fixed bed reactor, and the interior is provided with three layers of fixed trays 701, Each fixed column plate 701 is provided with a carbonylation reaction catalyst, and the carbonylation reactor 70 is also provided with a number of mixture inlets 702. The mixture inlets 702 are respectively arranged at the top of the carbonylation reactor 70 and between the adjacent fixed column plates 701. between.

After stripping through the separation column 80, the top of the separation column 80 is mainly unreacted dimethyl ether, which can be directly returned to the first micro-interface generator 50 through the separation tank 801 arranged at the top of the separation column 80 as the reaction feed of the carbonylation. The liquid phase from the bottom of the separation tank 801 is directly returned to the separation tower 80 for stripping separation and purification again.

The bottom of the separation tower is provided with a methyl acetate outlet 802, and the material going out from the methyl acetate outlet 802 at the bottom of the separation tower 80 is mainly methyl acetate, and is transported into the second micro-interface generator 90 by a pump, in order to improve the second The effect of the micro-interface generator 90 is that methyl acetate is preheated by the preheater 20 and then fed into the second micro-interface generator 90, and at the same time, hydrogen is fed into the second micro-interface generator 90 at the same time, The hydrogen is transported through the hydrogen storage tank 100. The hydrogen is fully mixed with the liquid methyl acetate in the second micro-interface generator 90 and pulverized into microbubbles, and then enters the hydrogenation reactor 110 for hydrogenation reaction.

The methyl acetate is subjected to hydrogenation to generate methanol and ethanol, which are transported to the second rectifying tower 120 for ethanol purification. The top of the second rectifying tower 120 is provided with a methanol outlet 1201, and the methanol outlet 1201 is returned to dimethyl ether through a pipeline. The reactor 10 is used as a methanol raw material, and a product extraction port 1202 is provided at the bottom of the second rectifying tower 120 for extraction of product ethanol. The tower top of the second rectifying tower 120 is provided with a tower top condenser, and the tower kettle is provided with a tower kettle reboiler. After the material from the methanol outlet 1201 is condensed by the tower top condenser, a part returns to the second rectification tower 120, and a part returns to the second rectification tower 120. It is discharged, and the discharged part can be directly returned to the dimethyl ether reactor 10 for use as a reaction raw material.

The micro-interface reaction system of this embodiment is provided with a micro-interface generator at a specific position, so as to improve the mass transfer effect of the entire reaction, reduce energy consumption, and at the same time improve the utilization rate of raw materials.

In the above-mentioned embodiment, it is not limited to setting a single micro-interface generator. In order to increase the effect of dispersion and mass transfer, additional micro-interface generators can also be added. The installation position is actually not limited, and it can be external or external. Built-in, when built-in, it can also be installed on the side wall of the kettle, so as to realize the hedge of the micro-bubbles from the outlet of the micro-interface generator. Interface generator way.

In the above embodiment, there is no specific requirement for the number of pump bodies, which can be set at corresponding positions as required.

The working process and principle of the coal-to-ethanol micro-interface reaction system of the present invention are briefly described below:

Nitrogen purges each equipment in the micro-interface reaction system, and then starts the operation. The raw methanol is first subjected to gas-phase catalytic dehydration reaction in the dimethyl ether reactor 10, and then goes to the first rectifying tower 40 for rectification. The dimethyl ether extracted by the side-line extraction mechanism of the rectifying tower 40 goes to the first micro-interface generator 50 to be mixed with CO for dispersion and crushing, and the dispersed and crushed mixture enters the carbonylation reactor 70 for carbonylation reaction, carbonylation The resulting reaction product goes to the separation tower 80 for stripping and separation, then comes out from the bottom of the separation tower 80 and goes to the second micro-interface generator 90 to mix, disperse and crush with hydrogen and then go to the hydrogenation reactor 110 for hydrogenation reaction, Finally, the hydrogenation reaction product is sent to the second rectification tower 120 for rectification to obtain the final product refined ethanol.

Wherein, the pressure of the carbonylation reaction is 2.5-3.0MPa, and the temperature of the carbonylation reaction is 200-230°C.

The pressure of the hydrogenation reaction is 2.5-3.0MPa, and the temperature of the hydrogenation reaction is 200-210°C.

The above process steps are cycled back and forth to make the entire synthesis system run smoothly.

In a word, compared with the micro-interface reaction system of coal-to-ethanol in the prior art, the micro-interface reaction system of coal-to-ethanol of the present invention has fewer equipment components, small footprint, low energy consumption, low cost, high safety, and high reaction efficiency. Controllable and high conversion rate of raw materials, it is equivalent to providing a micro-interface reaction system with stronger operability for the field of coal-to-ethanol, which is worthy of widespread application.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. Scope.

Claims

A micro-interface reaction system for coal-to-ethanol, comprising: a methanol-to-dimethyl ether reaction unit and a dimethyl ether-to-ethanol reaction unit connected in sequence, wherein the methanol is prepared by coal gasification;

The methanol-to-dimethyl ether reaction unit comprises: a dimethyl ether reactor; methanol is passed into the dimethyl ether reactor for gas-phase catalytic dehydration reaction, and the reacted product enters a first rectifying tower for dimethyl ether purification Rectification, part of the gas phase condensation after the rectification is returned to the first rectifying tower, and part of the dimethyl ether reactor is returned to the dimethyl ether reactor for re-reaction; ;

The dimethyl ether-to-ethanol reaction unit includes: a carbonylation reactor, a first micro-interface generator is arranged on the outside of the carbonylation reactor, and the first micro-interface generator is connected to the first micro-interface generator. The dimethyl ether separated by rectification in the distillation column, and carbon monoxide is introduced at the same time. After being dispersed and broken by the first micro-interface generator, it enters the carbonylation reactor for reaction, and the carbonylation reactor is connected to the second micro-interface. The generator is used to pass the carbonylation product into the second micro-interface generator, and the second micro-interface generator is fed with hydrogen at the same time, and enters the hydrogenation reaction after being dispersed and broken by the second micro-interface generator The reactor is used to carry out the hydrogenation reaction of methyl acetate, and the reaction product after the hydrogenation reaction is passed through the second rectifying tower to separate methanol and ethanol to obtain ethanol.
The micro-interface reaction system according to claim 1, wherein the methanol-to-dimethyl ether reaction unit comprises a heat exchanger, and the heat exchanger is used for heat exchange between the raw methanol and the gas-phase catalytic dehydration reaction product.
The micro-interface reaction system according to claim 1, wherein a extraction mechanism for side-line extraction of dimethyl ether is provided on the first rectifying column, and the extraction mechanism is connected to the first micro-interface. Generator connection.
The micro-interface reaction system according to claim 1, wherein the carbonylation reactor is a fixed bed reactor, and three layers of fixed trays are arranged inside, and a carbonylation reaction catalyst is arranged on each layer of the fixed trays. , the carbonylation reactor is provided with several reaction mixture inlets, and the reaction mixture inlets are respectively arranged at the top of the carbonylation reactor and between adjacent fixed trays.
The micro-interface reaction system according to claim 1, wherein a separation tower is arranged between the carbonylation reactor and the second micro-interface generator for removing gas-phase impurities in the carbonylation product.
The micro-interface reaction system according to claim 5, wherein the top of the separation tower is provided with a separation tank, the gas phase separated by the separation tank goes to the first micro-interface generator, and the liquid phase returns to the first micro-interface generator. The separation column is re-stripped for separation.
The micro-interface reaction system according to claim 5, wherein a methyl acetate outlet is provided at the bottom of the separation tower, and the methyl acetate outlet is connected with the second micro-interface generator through a pipeline.
The micro-interface reaction system according to claim 1, wherein a methanol outlet is provided at the top of the second rectifying column, and the methanol outlet is returned to the dimethyl ether reactor through a pipeline for use as a methanol raw material, The bottom of the second rectifying tower is provided with a product extraction port for extraction of product ethanol.
Adopt the reaction method of the micro-interface reaction system of the coal-to-ethanol described in any one of claim 1-8, it is characterized in that, comprising:

The raw material methanol is subjected to gas-phase catalytic dehydration and rectification to obtain dimethyl ether;

After the dimethyl ether and carbon monoxide are mixed, dispersed and crushed, carbonylation reaction is carried out to obtain a carbonylation reaction product;

After the carbonylation reaction product is mixed, dispersed and crushed with hydrogen, and subjected to hydrogenation reaction, ethanol is obtained by rectification.
The reaction method according to claim 9, wherein the pressure of the carbonylation reaction is 2.5-3.0MPa, and the temperature of the carbonylation reaction is 200-230°C;

Preferably, the pressure of the hydrogenation reaction is 2.5-3.0MPa, and the temperature of the hydrogenation reaction is 200-210°C.