阅读说明：本技术 一种微界面强化制备dmc的系统及制备方法 (System and method for preparing DMC (dimethyl formamide) through micro-interface reinforcement ) 是由 张志炳 孟为民 周政 王宝荣 杨高东 罗华勋 张锋 李磊 杨国强 田洪舟 曹宇 于 2021-07-16 设计创作，主要内容包括：本发明提供了一种微界面强化制备DMC的系统,包括：反应器和第一气液分离器；所述反应器的侧壁设置有出料口；所述反应器中反应得到的产物经所述出料口进入所述第一气液分离器中；所述反应器内设置有第一档板,所述第一档板与所述出料口的出料方向垂直；所述第一档板的高度低于所述出料口；所述第一档板将所述反应器内部分成反应区和出料区；所述第一档板位于所述出料口的一侧为出料区。本发明的反应系统所需反应温度和压力低,副反应少、甲醇转化率高,值得广泛推广应用。(The invention provides a system for preparing DMC (dimethyl formamide) by micro-interface reinforcement, which comprises: a reactor and a first gas-liquid separator; a discharge hole is formed in the side wall of the reactor; the product obtained by the reaction in the reactor enters the first gas-liquid separator through the discharge hole; a first baffle plate is arranged in the reactor, and the first baffle plate is vertical to the discharging direction of the discharging port; the height of the first baffle plate is lower than that of the discharge hole; the first baffle plate divides the interior of the reactor into a reaction zone and a discharge zone; one side of the first baffle plate, which is positioned at the discharge hole, is a discharge area. The reaction system of the invention has low reaction temperature and pressure, less side reaction and high methanol conversion rate, and is worthy of wide popularization and application.)

1. A system for preparing DMC by micro-interface strengthening, comprising: a reactor and a first gas-liquid separator; a discharge hole is formed in the side wall of the reactor; the product obtained by the reaction in the reactor enters the first gas-liquid separator through the discharge hole;

a first baffle plate is arranged in the reactor, and the first baffle plate is vertical to the discharging direction of the discharging port; the height of the first baffle plate is lower than that of the discharge hole; the first baffle plate divides the interior of the reactor into a reaction zone and a discharge zone; one side of the first baffle plate, which is positioned at the discharge hole, is a discharge area;

the side wall of the reaction zone is sequentially provided with a methanol inlet and a synthesis gas inlet from top to bottom; the methanol inlet is connected with a methanol pipeline, and the synthesis gas inlet is connected with a synthesis gas pipeline; an evaporator is arranged on the methanol pipeline; two micro-interface generators are arranged in the reaction zone, and outlets of the two micro-interface generators are opposite; the micro-interface generator positioned above is connected with the methanol pipeline through the methanol inlet, the micro-interface generator positioned below is connected with the synthesis gas pipeline through the synthesis gas inlet, and distributors are arranged at the outlets of the two micro-interface generators;

a second baffle plate is arranged between the first baffle plate and the discharge hole, and the second baffle plate is parallel to the first baffle plate; the height of the second baffle plate is higher than that of the discharge hole; a liquid separation area is formed between the first baffle plate and the second baffle plate; and a filter screen is arranged at the discharge port.

2. The system for the enhanced preparation of DMC as recited in claim 1, wherein the first baffle and the second baffle are both fixed to the inner wall of the reactor and the bottom of the first baffle and the second baffle are both spaced from the bottom wall of the reactor; the bottom of the second baffle plate and the bottom of the reactor form a reflux zone.

3. The system for preparing DMC by using micro-interface strengthening as defined in claim 1, wherein the distributor is tapered and has a plurality of distribution holes perpendicular to the wall of the distributor.

4. The system for preparing DMC by using the micro-interface strengthening method according to claim 1, wherein the bottom of the first baffle is provided with an arc-shaped guide plate; and the solid material separated by the liquid separation zone flows back to the reaction zone along the guide plate.

5. The system for preparing DMC by strengthening the interface of claim 1, wherein the first baffle has a height flush with the bottom of the discharge hole.

6. The system for preparing DMC by using micro-interface intensification as described in claim 1, wherein the top outlet of the first gas-liquid separator is connected with a first condenser, a second gas-liquid separator and a separation tower in sequence; and separating the product in the first gas-liquid separator into a gas-phase material and a liquid-phase material, wherein the gas-phase material enters the first condenser through a top outlet of the first gas-liquid separator.

7. The system for the micro-interface enhanced preparation of DMC as recited in claim 6, wherein a microbubble generator is disposed in the reaction zone, and the microbubble generator is located below the micro-interface generator; and the liquid-phase material separated by the first gas-liquid separator flows out from the bottom of the first gas-liquid separator and flows back to the reactor through the microbubble generator.

8. The system for preparing DMC through micro-interface enhanced according to claim 6, wherein the separation tower is provided with a liquid phase outlet and a gas phase outlet; the liquid phase outlet is connected with a reboiler; the gas phase outlet is connected with a second condenser; and after the mixed gas separated by the separation tower is condensed by the second condenser, one part of the mixed gas flows back to the second condenser, and the other part of the mixed gas flows into the reactor through the methanol pipeline.

9. The method for preparing the system for preparing DMC by using the micro-interface strengthening method as described in any one of claims 1-8, includes the following steps:

respectively crushing methanol and synthesis gas through a micro interface, mixing the crushed methanol and synthesis gas with a catalyst to perform carbonylation reaction, and performing gas-liquid separation to obtain a product DMC; the catalyst is cuprous chloride.

10. The process according to claim 9, wherein the carbonylation reaction temperature is 110 ℃ and 115 ℃ and the pressure is 1.5 to 2.0 MPa.

Technical Field

The invention relates to the field of methanol carbonylation reaction preparation, in particular to a system and a method for preparing DMC (dimethyl formamide) by micro-interface reinforcement.

Background

A liquid-phase methanol oxidizing and carbonylating method based on CH₃OH、O₂And a method for synthesizing DMC (dimethyl carbonate) by CO under the action of catalyst.

The existing production process flow is generally carried out in two sets of reaction devices. Each set of reaction device consists of two parallel reactors and a gas-liquid separation tank. The reaction temperature is 115 ℃ and 120 ℃, and the reaction pressure is 2.2-2.5 MPaG. The normal operation liquid level of the gas-liquid separation tank is about 50 percent. The catalyst is cuprous chloride catalyst, the particle size of the catalyst particles is 200 meshes (74 mu m), the catalyst particles are in a pseudo-homogeneous state in the slurry, and the content is 1.5-3% (wt).

The liquid phase feeding of the reactor is fresh methanol and methanol circulated by the system, and the fresh methanol and the methanol are mixed and then enter a downcomer at the bottom of the gas-liquid separation tank to flow into the bottom of the reactor respectively. Fresh O in gas phase feed₂And CO and circulating gas (mainly CO) are mixed and then respectively enter the two reactors in a bubbling mode through a distributor at the bottom of the two reactors. To ensure O₂Fully reacting, and controlling O in the exhaust gas₂The content is below the explosive limit and the oxygen concentration in the feed is < 5%. In two reactors, O₂And generating DMC and water by the CO and the methanol under the action of a catalyst. The top parts of the two reactors are provided with pipelines connected with a gas-liquid separation tank, and the gas-liquid mixture on the upper parts of the reactors enters the gas-liquid separation tankSeparation is carried out. The separated gas phase mixture is sent to a downstream device, and the main components are CO, DMC, methanol and CO₂And water. The liquid phase at the bottom of the separation tank is mixed with the raw material methanol from the downcomer and then circulates back to the bottoms of the two reactors.

The methanol oxidative carbonylation reaction is exothermic, the heat of reaction generated by 1mol of DMC is about 310kJ, the reaction material is discharged in a gas phase, and the latent heat of vaporization is 31 kJ/mol. Because the conversion per pass of the raw materials is low, the total exothermic amount of the reaction is relatively small, and the constant reaction temperature needs to be regulated by supplementing heat through a U-shaped heat exchanger inside the reactor. 4 heat exchangers are arranged in each reactor, and the steam consumption is about 0-10 t/h.

The main problems of the existing DMC production process are as follows:

(1) the raw material gas mixture is initially distributed at the bottom of the reactor through a distributor and then is bubbled into a liquid phase. Because the opening of the distributor is in millimeter level (phi 5mm), the diameter of the generated bubbles is larger (8-15 mm), the gas-liquid interface area is smaller, the initially distributed bubbles are easy to coalesce in the rising process, the bubbles in the reactor are distributed unevenly, and in addition, the liquid circulation adopts a density difference circulation mode, the flow rate is slower (less than 0.1m/s), so that the gas-liquid mass transfer rate is lower, and the macroscopic reaction rate is seriously lower than the design expected value;

(2)O₂the consumption is high, but the actual effective utilization rate is low;

(3) the single-pass conversion rate of CO is about 2-8%, and the feeding amount of CO is more, so that the power consumption of a fresh CO compressor and a circulating CO compressor is larger;

(4) because the product DMC stays in the system for too long time and undergoes hydrolysis reaction with water, CO is generated₂With CO and O₂Side reactions are easy to occur, and the factors greatly reduce the conversion rate of raw materials.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The first purpose of the invention is to provide a system for preparing DMC by micro-interface reinforcement, which can effectively trap solid materials in the product by arranging a first baffle plate and a second baffle plate in a reactor and utilizing a liquid separation area formed between the first baffle plate and the second baffle plate; the reactor is internally provided with the micro-interface generator to disperse and crush the methanol and the synthesis gas respectively and then carry out carbonylation reaction, so that the gas-liquid mass transfer area of the methanol and the synthesis gas is increased, the reaction rate is increased, and the reaction energy consumption is reduced.

The second purpose of the invention is to provide a preparation method adopting the system, the method is simple and convenient to operate, and by applying the system, the reaction energy consumption is reduced, and the single-pass conversion rate of methanol and the yield of DMC are improved.

In order to achieve the above purpose of the present invention, the following technical solutions are adopted:

the invention provides a system for preparing DMC (dimethyl formamide) by micro-interface reinforcement, which comprises: a reactor and a first gas-liquid separator; a discharge hole is formed in the side wall of the reactor; the product obtained by the reaction in the reactor enters the first gas-liquid separator through the discharge hole;

a first baffle plate is arranged in the reactor, and the first baffle plate is vertical to the discharging direction of the discharging port; the height of the first baffle plate is lower than that of the discharge hole; the first baffle plate divides the interior of the reactor into a reaction zone and a discharge zone; one side of the first baffle plate, which is positioned at the discharge hole, is a discharge area;

the side wall of the reaction zone is sequentially provided with a methanol inlet and a synthesis gas inlet from top to bottom; the methanol inlet is connected with a methanol pipeline, and the synthesis gas inlet is connected with a synthesis gas pipeline; an evaporator is arranged on the methanol pipeline; two micro-interface generators are arranged in the reaction zone, and outlets of the two micro-interface generators are opposite; the micro-interface generator positioned above is connected with the methanol pipeline through the methanol inlet, the micro-interface generator positioned below is connected with the synthesis gas pipeline through the synthesis gas inlet, and distributors are arranged at the outlets of the two micro-interface generators;

a second baffle plate is arranged between the first baffle plate and the discharge hole, and the second baffle plate is parallel to the first baffle plate; the height of the second baffle plate is higher than that of the discharge hole; a liquid separation area is formed between the first baffle plate and the second baffle plate; and a filter screen is arranged at the discharge port.

In the prior art, a raw material gas mixture is initially distributed at the bottom of a reactor through a distributor and then bubbled into a liquid phase. Because the opening of the distributor is in millimeter level (phi 5mm), the diameter of the generated bubbles is larger (8-15 mm), the gas-liquid interface area is smaller, the initially distributed bubbles are easy to coalesce in the rising process, the bubbles in the reactor are not uniformly distributed, in addition, the liquid circulation adopts a density difference circulation mode, the flow rate is lower (less than 0.1m/s), so that the gas-liquid mass transfer rate is lower, the macroscopic reaction rate is seriously lower than the designed expected value, and because the product DMC stays in the system for too long time and undergoes hydrolysis reaction with water, CO is generated₂With CO and O₂Side reactions are easy to occur, and the factors greatly reduce the conversion rate of raw materials.

In order to solve the technical problems, the invention provides a system for preparing DMC (dimethyl carbonate) by micro-interface reinforcement, which respectively disperses and crushes methanol and synthesis gas into micron-sized micro-bubbles by a micro-interface generator arranged in a reactor, improves the phase boundary mass transfer area between the methanol and the synthesis gas, improves the reaction rate, reduces the retention time of raw materials in the reactor, and thus reduces the occurrence of side reactions; meanwhile, the reaction energy consumption can be effectively reduced, and the reaction conversion rate can be improved.

Preferably, the first baffle plate and the second baffle plate are both fixed on the inner wall of the reactor, and the bottoms of the first baffle plate and the second baffle plate are both spaced from the bottom wall of the reactor; the bottom of the second baffle plate and the bottom of the reactor form a reflux zone. A slow flow layer is formed in a gap between the first baffle plate and the second baffle plate, liquid forms layering in the slow flow layer, and solid particles separated from the bottom flow back to the reaction zone along the reflux zone.

Preferably, the distributor is conical, and a plurality of distribution holes are arranged on the distributor and are perpendicular to the wall of the distributor. This arrangement enables the microbubbles to flow in different directions along the distribution holes, thereby promoting uniform distribution of the microbubbles.

Preferably, the bottom of the first baffle plate is provided with an arc-shaped guide plate; and the solid material separated by the liquid separation zone flows back to the reaction zone along the guide plate.

Preferably, the height of the first baffle is flush with the bottom of the discharge hole. And a height difference is formed between the first baffle plate and the second baffle plate, and solid particles mixed in the liquid are removed by utilizing the height difference.

The reactor is divided into a reaction area and a discharge area by a first baffle plate, and two micro-interface generators are arranged in the reaction area to disperse and crush the methanol and the synthesis gas. During reaction, methanol and synthesis gas are dispersed and crushed into micro bubbles by the micro interface generator and then react with the participation of the catalyst, so that the phase boundary mass transfer area between the methanol and the synthesis gas is increased, and the energy consumption is reduced; the outlets of the two micro-interface generators are opposite, so that the opposite impact effect can be achieved, and the uniform distribution of micro-bubbles can be realized.

It should be noted that, when the micro-interface generator is arranged, the micro-interface generator positioned at the upper part is connected with the methanol pipeline, the micro-interface generator positioned at the lower part is connected with the synthesis gas pipeline, the synthesis gas is relatively synthesized in advance by a gas source, CO in the synthesis gas raw material is combustible, and O and CO are combustible₂The reaction is easy to explode, so in order to improve the safety of the reaction, the air inlet is arranged at a lower position as much as possible, and meanwhile, the micro-interface generator for crushing methanol is arranged at the upper part and the micro-interface generator for crushing synthesis gas is arranged at the lower part in view of the fact that the micro-interface generator flows towards the top of the reactor more easily after entering the reactor.

The invention also arranges a distributor at the outlet of the micro-interface generator, and the micro-bubbles flow to different directions along the distribution holes through the distribution holes on the distributor, thereby promoting the uniform distribution of the micro-bubbles. Therefore, the distributor and the micro-interface generator are combined and applied, and the structure of the reactor is combined, so that the application effect of the micro-interface generator is improved.

In addition, the reactor of the invention is provided with a first baffle plate, a second baffle plate and a filter screen, and the first baffle plate, the second baffle plate and the filter screen are all arranged to prevent the solid catalyst in the reactor from flowing out along the discharge port. Wherein, a height difference is formed between the first baffle plate and the second baffle plate, so that liquid flows downwards along a gap between the first baffle plate and the second baffle plate, a slow flow layer is formed between the gap between the first baffle plate and the second baffle plate, liquid forms layering in the slow flow layer, and solid particles separated from the bottom flow back to the reaction zone along the reflux zone; the filter screen further filters the liquid material that flows out, prevents that solid catalyst from flowing out.

It will be appreciated by those skilled in the art that the micro-interface generator used in the present invention is described in the prior patents of the present inventor, such as the patents of application numbers CN201610641119.6, CN201610641251.7, CN201710766435.0, CN106187660, CN105903425A, CN109437390A, CN205833127U and CN 207581700U. The detailed structure and operation principle of the micro bubble generator (i.e. micro interface generator) is described in detail in the prior patent CN201610641119.6, which describes that "the micro bubble generator comprises a body and a secondary crushing member, wherein the body is provided with a cavity, the body is provided with an inlet communicated with the cavity, the opposite first end and second end of the cavity are both open, and the cross-sectional area of the cavity decreases from the middle of the cavity to the first end and second end of the cavity; the secondary crushing member is disposed at least one of the first end and the second end of the cavity, a portion of the secondary crushing member is disposed within the cavity, and an annular passage is formed between the secondary crushing member and the through holes open at both ends of the cavity. The micron bubble generator also comprises an air inlet pipe and a liquid inlet pipe. "the specific working principle of the structure disclosed in the application document is as follows: liquid enters the micro-bubble generator tangentially through the liquid inlet pipe, and gas is rotated at a super high speed and cut to break gas bubbles into micro-bubbles at a micron level, so that the mass transfer area between a liquid phase and a gas phase is increased, and the micro-bubble generator in the patent belongs to a pneumatic micro-interface generator.

In addition, the first patent 201610641251.7 describes that the primary bubble breaker has a circulation liquid inlet, a circulation gas inlet and a gas-liquid mixture outlet, and the secondary bubble breaker communicates the feed inlet with the gas-liquid mixture outlet, which indicates that the bubble breakers all need to be mixed with gas and liquid, and in addition, as can be seen from the following drawings, the primary bubble breaker mainly uses the circulation liquid as power, so that the primary bubble breaker belongs to a hydraulic micro-interface generator, and the secondary bubble breaker simultaneously introduces the gas-liquid mixture into an elliptical rotating ball for rotation, thereby realizing bubble breaking in the rotating process, so that the secondary bubble breaker actually belongs to a gas-liquid linkage micro-interface generator. In fact, the micro-interface generator is a specific form of the micro-interface generator, whether it is a hydraulic micro-interface generator or a gas-liquid linkage micro-interface generator, however, the micro-interface generator adopted in the present invention is not limited to the above forms, and 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 adopt. Furthermore, the prior patent 201710766435.0 states that the principle of the bubble breaker is that high-speed jet flows are used to achieve mutual collision of gases, and also states that the bubble breaker can be used in a micro-interface strengthening reactor to verify the correlation between the bubble breaker and the micro-interface generator; moreover, in the prior patent CN106187660, there is a related description on the specific structure of the bubble breaker, see paragraphs [0031] to [0041] in the specification, and the accompanying drawings, which illustrate the specific working principle of the bubble breaker S-2 in detail, the top of the bubble breaker is a liquid phase inlet, and the side of the bubble breaker is a gas phase inlet, and the liquid phase coming from the top provides the entrainment power, so as to achieve the effect of breaking into ultra-fine bubbles, and in the accompanying drawings, the bubble breaker is also seen to be of a tapered structure, and the diameter of the upper part is larger than that of the lower part, and also for better providing the entrainment power for the liquid phase.

Since the micro-interface generator was just developed in the early stage of the prior patent application, the micro-interface generator was named as a micro-bubble generator (CN201610641119.6), a bubble breaker (201710766435.0) and the like in the early stage, and is named as a micro-interface generator in the later stage along with the continuous technical improvement, and the micro-interface generator in the present invention is equivalent to the micro-bubble generator, the bubble breaker and the like in the prior art, and has different names. In summary, the micro-interface generator of the present invention belongs to the prior art.

Preferably, the top outlet of the first gas-liquid separator is sequentially connected with a first condenser, a second gas-liquid separator and a separation tower; and separating the product in the first gas-liquid separator into a gas-phase material and a liquid-phase material, wherein the gas-phase material enters the first condenser through a top outlet of the first gas-liquid separator.

Preferably, a microbubble generator is arranged in the reaction zone, and the microbubble generator is positioned below the micro-interface generator; and the liquid-phase material separated by the first gas-liquid separator flows out from the bottom of the first gas-liquid separator and flows back to the reactor through the microbubble generator.

Preferably, a circulating pump and a heat exchanger are arranged between the first gas-liquid separator and the micro-bubble separator, and the liquid-phase material flows into the micro-bubble separator after entering the heat exchanger for heat exchange through the circulating pump. The temperature control of the reactor can be realized by controlling the circulating water inlet flow of the heat exchanger.

Preferably, the separation column is provided with a liquid phase outlet and a gas phase outlet; the liquid phase outlet is connected with a reboiler; the gas phase outlet is connected with a second condenser; and after the mixed gas separated by the separation tower is condensed by the second condenser, one part of the mixed gas flows back to the second condenser, and the other part of the mixed gas flows into the reactor through the methanol pipeline.

The invention also provides a preparation method of the system for preparing DMC by adopting the micro-interface reinforcement, which comprises the following steps:

respectively crushing methanol and synthesis gas through a micro interface, mixing the crushed methanol and synthesis gas with a catalyst to perform carbonylation reaction, and performing gas-liquid separation to obtain a product DMC; the catalyst is cuprous chloride.

Preferably, the carbonylation reaction temperature is 110-115 ℃ and the pressure is 1.5-2.0 MPa.

The DMC obtained by the reaction method of the invention has high yield. And the preparation method has the advantages of low reaction temperature, greatly reduced pressure and remarkably reduced cost.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the system for preparing DMC in a micro-interface strengthening way, the micro-interface generator arranged in the reactor is used for dispersing and crushing methanol and synthesis gas into micro-bubbles, so that the phase boundary mass transfer area between the methanol and the synthesis gas is increased, the reaction rate is increased, the retention time of raw materials in the reactor is reduced, and the occurrence of side reactions is reduced; meanwhile, the reaction energy consumption can be effectively reduced, and the reaction conversion rate is improved;

(2) the micro-bubbles flow to different directions along the distribution holes through the distribution holes on the distributor, so that the uniform distribution of the micro-bubbles is promoted;

(3) the solid catalyst in the product can be effectively intercepted by arranging the first baffle plate and the second baffle plate in the reactor and utilizing a liquid separation area formed between the first baffle plate and the second baffle plate;

(4) the liquid material that flows out is further filtered through the filter screen, further prevents solid catalyst outflow.

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 only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 is a schematic structural diagram of a system for preparing DMC by micro-interface enhanced method according to example 1 of the present invention;

FIG. 2 is a schematic structural view of a reactor provided in example 1 of the present invention;

fig. 3 is a schematic structural diagram of a distributor provided in embodiment 1 of the present invention.

Wherein:

10-a reactor; 101-methanol inlet;

102-a syngas inlet; 103-a micro-interface generator;

104-a distributor; 1041-distribution holes;

105-a microbubble generator; 106-a first baffle;

107-second baffle; 108-a guide plate;

109-a filter screen; 1010-discharge hole;

20-an evaporator; 30-methanol line;

40-a synthesis gas line; 50-a first gas-liquid separator;

60-a first condenser; 70-a second gas-liquid separator;

80-a second condenser; 90-a separation column;

100-a reboiler; 110-heat exchanger.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In order to more clearly illustrate the technical solution of the present invention, the following description is made in the form of specific embodiments.

Example 1

Referring to fig. 1-3, the present invention provides a system for preparing DMC by micro-interface enhancement, comprising: a reactor 10 and a first gas-liquid separator 50; the side wall of the reactor 10 is provided with a discharge hole 1010; the product obtained from the reaction in the reactor 10 enters the first gas-liquid separator 50 through the discharge port 1010.

As shown in fig. 2, a first baffle 106 is disposed in the reactor 10, and the first baffle 106 is perpendicular to the discharging direction of the discharging port 1010; the height of the first baffle 106 is lower than the discharge hole 1010; the first baffle 106 divides the interior of the reactor 10 into a reaction zone and a discharge zone; one side of the first baffle 106, which is located at the discharge port 1010, is a discharge area; a second baffle plate 107 is arranged between the first baffle plate 106 and the discharge hole 1010, and the second baffle plate 107 is parallel to the first baffle plate 106; the height of the second baffle plate 107 is higher than that of the discharge hole 1010; a liquid separation area is formed between the first baffle 106 and the second baffle 107; the discharge port 1010 is provided with a filter screen 109.

The first baffle 106 and the second baffle 107 are fixed on the inner wall of the reactor 10, and the bottoms of the first baffle 106 and the second baffle 107 are spaced from the bottom wall of the reactor 10; the bottom of the second baffle 107 forms a reflux zone with the bottom of the reactor 10. A slow flow layer is formed in a gap between the first baffle plate 106 and the second baffle plate 107, liquid forms layering in the slow flow layer, and solid particles separated from the bottom flow back to the reaction zone along the reflux zone.

Wherein, the bottom of the first baffle 106 is provided with an arc-shaped guide plate 108; the solid material separated by the liquid separation zone flows back to the reaction zone along guide plate 108. The height of the first baffle 106 is flush with the bottom of the discharge hole 1010. A height difference is formed between the first baffle 106 and the second baffle 107, and solid particles mixed in the liquid are removed by the height difference.

Continuing to refer to fig. 2, the side wall of the reaction zone is provided with a methanol inlet 101 and a synthesis gas inlet 102 from top to bottom in sequence; the methanol inlet 101 is connected with a methanol pipeline 30, and the synthesis gas inlet 102 is connected with a synthesis gas pipeline 40; the methanol pipeline 30 is provided with an evaporator 20; two micro-interface generators 103 are arranged in the reaction zone, and outlets of the two micro-interface generators 103 are opposite; the upper micro-interface generator 103 is connected with the methanol pipeline 30 through a methanol inlet 101, the lower micro-interface generator 103 is connected with the synthesis gas pipeline 40 through a synthesis gas inlet 102, and distributors 104 are arranged at the outlets of the two micro-interface generators 103.

As shown in fig. 3, the distributor 104 is tapered, and a plurality of distribution holes 1041 are formed on the distributor 104, and the distribution holes 1041 are perpendicular to the wall of the distributor 104. This arrangement enables the micro-bubbles to flow in different directions along the distribution holes 1041, thereby promoting uniform distribution of the micro-bubbles.

Referring to fig. 1, a top outlet of the first gas-liquid separator 50 is connected with a first condenser 60, a second gas-liquid separator 70 and a separation tower 90 in sequence; the product in the first gas-liquid separator 50 is separated into a gas phase material and a liquid phase material, the liquid phase material being mainly unreacted methanol. The gas phase material enters the first condenser 60 through the top outlet of the first gas-liquid separator 50, and then enters the second gas-liquid separator 70 through the first condenser 60, the gas in the product is further separated by the second gas-liquid separator 70, and the liquid flows into the separation tower 90. The gas separated by the second gas-liquid separator 70 is mainly water, carbon monoxide and carbon dioxide.

Wherein, a microbubble generator 105 is arranged in the reaction zone, and the microbubble generator 105 is positioned below the micro-interface generator 103; the liquid-phase material separated by the first gas-liquid separator 50 flows out from the bottom of the first gas-liquid separator 50 and flows back to the reactor 10 through the microbubble generator 105.

With reference to fig. 1, a circulation pump and a heat exchanger 110 are disposed between the first gas-liquid separator 50 and the micro-bubble separator, and the liquid-phase material enters the heat exchanger 110 through the circulation pump to exchange heat and then flows into the micro-bubble separator. The temperature control of the reactor 10 can be achieved by controlling the amount of circulating water fed to the heat exchanger 110.

The separation column 90 is provided with a liquid phase outlet and a gas phase outlet; the liquid phase outlet is connected with a reboiler 100; the gas phase outlet is connected with a second condenser 80; the mixed gas separated by the separation tower 90 is condensed by the second condenser 80, and then a part of the condensed mixed gas flows back to the second condenser 80, and the other part of the condensed mixed gas flows into the reactor 10 through the methanol pipeline 30.

During reaction, methanol and mixed gas are simultaneously introduced into the reactor 10, and are respectively dispersed into micro bubbles by the micro interface generator 103, and then the reaction is carried out under the participation of a catalyst, and the reaction product is purified by the first gas-liquid separator 50, the second gas-liquid separator 70 and the separation tower 90, so as to obtain the product DMC.

Wherein, the specific process parameters of the reaction are as follows:

methanol conversion-mol of methanol converted/mol of methanol fed,

DMC yield is the molar flow rate of DMC produced per molar amount of methanol fed.

As can be seen from the above table, the conversion per pass of methanol reached 18.44% (typically 10-15% for the prior art) and the DMC yield reached 16.39% (typically 8-12% for the prior art). The reaction temperature is 115 ℃ and the pressure is 1.8MPa, while the existing reaction temperature is generally 120 ℃ and 125 ℃ and the pressure is 2.2-2.5MPa, thus the system of the embodiment has obviously reduced temperature and pressure compared with the existing process.

Example 2

This example is different from example 1 only in terms of process parameters, and the specific process parameters are as follows:

wherein the reaction temperature is 110 ℃ and the pressure is 1.5 MPa.

Through calculation, the conversion per pass of the methanol reaches 18.87 percent, and the yield of the DMC reaches 16.99 percent. It can be seen that the system of the present embodiment has a significant reduction in temperature and pressure relative to existing processes.

Example 3

This example is different from example 1 only in terms of process parameters, and the specific process parameters are as follows:

wherein the reaction temperature is 115 ℃ and the pressure is 2 MPa.

Through calculation, the conversion per pass of the methanol reaches 18.81 percent, and the yield of the DMC reaches 16.24 percent. It can be seen that the system of the present embodiment has a significant reduction in temperature and pressure relative to existing processes.

In a word, compared with the prior art, the reaction system of the invention has the advantages of low reaction temperature and pressure, less side reaction, high methanol conversion rate and wide popularization and application value.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.