CN211339349U

CN211339349U - Synthesis device for polymethoxy dimethyl ether

Info

Publication number: CN211339349U
Application number: CN201921933093.8U
Authority: CN
Inventors: 梁旭; 孙维毅
Original assignee: Wuxi Helibang Chemical Technology Co ltd
Current assignee: Wuxi Helibang Chemical Technology Co ltd
Priority date: 2019-11-11
Filing date: 2019-11-11
Publication date: 2020-08-25
Anticipated expiration: 2029-11-11

Abstract

The utility model discloses a synthesis device for polyoxymethylene dimethyl ethers, which belongs to the technical field of energy chemical industry, and comprises a catalytic rectification tower, a methylal refining tower, a catalytic rectification tower kettle and a secondary reaction spray tower, the output end of the catalytic rectifying tower is fixedly connected with a flange, the methylal refining tower, the tower kettle of the catalytic rectifying tower and the secondary reaction spray tower through pipelines, the input end of the catalytic rectifying tower is connected with a pump inlet pipe through a flange, the input end of the pump inlet pipe is connected with a pre-reactor through a flange, the synthesis device for polymethoxy dimethyl ether adopts a catalytic rectification principle, is matched with two-stage reaction, extracts an intermediate with the polymerization degree of n-2 generated by a system, continuously reacts to generate a component dmm3-5 product which best meets the requirement of being used as a diesel additive, and can simply and efficiently obtain a target product with n-3-5 as the main component.

Description

Synthesis device for polymethoxy dimethyl ether

Technical Field

The utility model relates to an energy chemical industry technical field specifically is a synthesizer for gathering methoxy dimethyl ether.

Background

Global energy has entered a severe exploitation period. High-quality energy is less and less, and the energy price is increasing. Particularly, after the crisis of crude oil, various countries have gradually started to reduce the production and increase the price of the crude oil. The oil price will gradually rise in the future. The energy structure of China is characterized in that: the coal, the oil and the gas are rich, the economy is continuously and rapidly increased, the energy demand is higher and higher, and the contradiction between the social and economic development and the petroleum supply is increasingly prominent. The development of coal liquefaction and oil formation technology is of strategic importance. In addition, the methanol productivity is seriously surplus in China, and the development of methanol downstream products and the extension of the industrial chain of coal chemical industry have practical significance. After the northwest coal production industry is subjected to multiple national industry adjustments, the original rough coal industry chain is further upgraded. Further deep processing of coal into methanol and the trend downstream has become a trend for the emerging coal industry in the future.

With the progress of social economy, the number of automobiles is obviously increased, and automobile exhaust emissions become one of important causes of urban haze. Compared with gasoline, diesel oil has higher boiling point and low H/C mass ratio, so that more waste gases such as CO, oxynitride, particulate matters and the like are discharged in the combustion process of the diesel oil, and the pollution caused by the waste gases is more serious than that caused by the gasoline. Therefore, the improvement of diesel combustion efficiency, the reduction of pollution emission and the improvement of urban air quality are important environmental protection tasks at present.

The polymethoxy dimethyl ether is a recognized clean diesel oil component in the world, and the cetane number of the polymethoxy dimethyl ether is more than or equal to 70, and the polymethoxy dimethyl ether does not contain sulfur and aromatic hydrocarbon. The additive is added into diesel according to the proportion of 5-20 percent, can improve the cetane number of the diesel, promote combustion and obviously reduce the emission of harmful gases such as PM2.5, PM10, NOx, CO and the like in automobile exhaust. Due to the excellent performance of polyoxymethylene dimethyl ethers, the synthesis process thereof has become a popular subject of domestic and foreign research.

At present, polymethoxy dimethyl ether is mostly generated by reacting methylal/methanol with formaldehyde (formaldehyde can be from aqueous formaldehyde solution/trioxymethylene/paraformaldehyde) under the catalysis of an acid catalyst. For the separation of the residual unreacted formaldehyde in the reaction solution, alkali neutralization reaction is generally adopted, and after the alcohol substances are generated by hydrogenation, conventional rectification separation is carried out. Since the alkali neutralizes formaldehyde in the reaction solution, a large amount of raw materials are consumed, and a large amount of sewage is generated. The industrial production is not economical. Hydrogenation results in high power consumption and high hydrogen cost. If formaldehyde is not treated and is directly distilled, the temperature is high, and the formaldehyde is easily subjected to disproportionation reaction to generate formic acid in the process of heating and vaporizing reaction liquid. The formic acid decomposes the product during the separation process to produce methylal and formaldehyde. According to the national seven standards, n is 3-5 which is the best diesel additive, and the flash point of the product n is 2 which does not meet the diesel standard, so that the product can only be used in the solvent market, and the product can only be returned to the system for conversion again for diesel users.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a synthesizer for gathering methoxy dimethyl ether to solve the current formaldehyde in the alkali neutralization reaction liquid that proposes among the above-mentioned background art, consumed a large amount of raw materials, and produced a large amount of sewage. The industrial production is not economical. Hydrogenation results in high power consumption and high hydrogen cost. If formaldehyde is not treated and is directly distilled, the temperature is high, and the formaldehyde is easily subjected to disproportionation reaction to generate formic acid in the process of heating and vaporizing reaction liquid. The formic acid decomposes the product during the separation process to produce methylal and formaldehyde. The separation efficiency in the process is low, products are further decomposed, and n is 3-5 which is the best diesel additive in the polymethoxy dimethyl ether dmmn series according to the national seventh standard. The flash point of the product of which n is 2 does not meet the diesel standard, and the product can only be used in the solvent market, and aiming at the problem that the part of the product can only return to the system to be converted again.

In order to achieve the above object, the utility model provides a following technical scheme: a synthesizer for polyoxymethylene dimethyl ether comprises a catalytic rectification tower, a methylal refining tower, a catalytic rectification tower kettle and a secondary reaction spray tower, wherein the output end of the catalytic rectification tower is fixedly connected with the methylal refining tower, the catalytic rectification tower kettle and the secondary reaction spray tower through a pipeline and a flange, the input end of the catalytic rectification tower is connected with a pump inlet pipe through a flange, the input end of the pump inlet pipe is connected with a pre-reactor through a flange, the input end of the pre-reactor is connected with a formaldehyde pipe and a methylal pipe through a flange, the output end of the catalytic rectification tower is connected with the top of the catalytic rectification tower through a pipeline and a flange, the output end of the top of the catalytic rectification tower is fixedly connected with the input end of the methylal refining tower through a pipeline and a flange, the input end of the catalytic rectification tower is connected with a methylal supplement pipe through a pipeline and a flange, the output of catalytic rectification tower pass through trunk line and flange with the input fixed connection of catalytic rectification tower cauldron, the circumference outer wall of trunk line has the pipeline through flange joint, the output of pipeline has the cooler through flange joint, the output of second grade reaction spray column has the second grade reaction spray column top through pipeline and flange joint, the output of second grade reaction spray column top pass through pipeline and flange with methylal refining tower fixed connection, the output of catalytic rectification tower cauldron has the top of the tower pressure-controlled valve through pipeline and flange joint, the output of top of the tower pressure-controlled valve pass through pipeline and flange with the input fixed connection of second grade reaction spray column, the input of methylal refining tower has thick methylal pipe through flange joint, the output of thick methylal pipe pass through flange with second grade reaction spray column top fixed connection, the output of methylal refined tower pass through auxiliary line and flange with methylal additional pipe fixed connection, the circumference outer wall of auxiliary line has the pipeline through flange joint, the pipeline with second grade reaction spray column fixed connection, second grade reaction spray column's output is connected with the cooler through pipeline and flange, the output of cooler pass through pipeline and flange with second grade reaction spray column's input fixed connection.

Preferably, the catalytic distillation column is divided into a stripping section, a reaction section and a rectification section.

Preferably, the secondary reaction spray tower packing wraps the catalyst, reactants are converted in the spray absorption process, the packing is regular wire mesh packing, a float valve tower plate or a bubble cap plate, the regular wire mesh packing is adopted, and the catalyst is wrapped by a 60-100-mesh stainless steel wire mesh and is wrapped by a 1: 5 to 1: the volume ratio of 10 is uniformly filled in the middle of the structured packing.

Preferably, the theoretical plate number of the methylal refining tower is 20-60.

Preferably, the cooler is a plate heat exchanger with a compact structure, the heat exchange area is 100-500 square meters, and the cooling medium is circulating cooling water.

Compared with the prior art, the beneficial effects of the utility model are that: this kind of synthesizer for gathering methoxy dimethyl ether, this utility model is to the principle that the reaction cascade goes on, will contain the reaction liquid component of part dmm2 and take out from catalytic rectification tower and send to the vary voltage rectifying column, and the component that contains dmm2 and formaldehyde is obtained at the top of the vary voltage rectifying column, and this strand of gaseous phase component further reacts in the second grade reaction sprays the reaction liquid that the system converts into dmm3-5 of higher degree of polymerization. The mixture is pumped to a pressure swing rectifying tower for further separation, Dmm2 is only used as an intermediate component in the process flow and finally completely participates in the synthesis of Dmm3-5, and a small amount of lost Dmm2 enters a methylal unit and is decomposed into formaldehyde and methylal on a catalyst. The process has the advantages of compact and simple flow, rapid raw material conversion and higher conversion rate.

Drawings

Fig. 1 is a schematic view of the process structure of the present invention.

In the figure: 001 formaldehyde tube, 002 methylal tube, 01 pre-reactor, 02 catalytic rectifying tower, 004 catalytic rectifying tower top, 005 methylal supplement tube, 05 methylal refining tower, 010 secondary reaction spray tower top, 11 catalytic rectifying tower kettle, 14 tower top pressure control valve, 15 secondary reaction spray tower, 016 coarse methylal tube and 17 cooler.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The utility model provides a synthesizer for gathering methoxy dimethyl ether through the combination application of accessory, has solved present synthetic product flow long, and the raw materials circulation volume is big, and the equipment investment who brings is big, problem that the unit consumption is high. The process flow, referring to fig. 1, comprises a catalytic distillation tower 02, a methylal refining tower 05, a catalytic distillation tower kettle 11 and a secondary reaction spray tower 15;

referring to fig. 1 again, the output end of the catalytic rectification tower 02 is fixedly connected with a flange and a methylal refining tower 05 through a pipeline, specifically, the input end of the catalytic rectification tower 02 is connected with a pumping pipe through a flange, the input end of the pumping pipe is connected with a pre-reactor 01 through a flange, the input end of the pre-reactor 01 is connected with a formaldehyde pipe 001 and a methylal pipe 002 through a flange, the output end of the catalytic rectification tower 02 is connected with a catalytic rectification tower top 004 through a pipeline and a flange, the output end of the catalytic rectification tower top 004 is fixedly connected with the input end of the methylal refining tower 05 through a pipeline and a flange, the input end of the catalytic rectification tower 02 is connected with a methylal supplementing pipe 005 through a pipeline and a flange, and the number of theoretical plates of the methylal refining tower 05 is 20-60;

referring to fig. 1 again, the output end of the catalytic rectifying tower 02 is fixedly connected with the flange and the catalytic rectifying tower kettle 11 through a pipeline, specifically, the output end of the catalytic rectifying tower 02 is fixedly connected with the input end of the catalytic rectifying tower kettle 11 through a main pipeline and a flange, the circumferential outer wall of the main pipeline is connected with a pipeline through a flange, the output end of the pipeline is fixedly connected with the cooler 17 through a flange, the output end of the secondary reaction spray tower 15 is connected with the secondary reaction spray tower top 010 through a pipeline and a flange, the output end of the secondary reaction spray tower top 010 is fixedly connected with the methylal rectifying tower 05 through a pipeline and a flange, the output end of the catalytic rectifying tower kettle 11 is connected with the tower top pressure control valve 14 through a pipeline and a flange, the output end of the tower top pressure control valve 14 is fixedly connected with the input end of the secondary reaction spray tower 15 through a pipeline and a flange, the input end of the methylal rectifying tower, the output end of the coarse methylal tube 016 is fixedly connected with the top 010 of the secondary reaction spraying tower through a flange;

referring to fig. 1 again, the output end of the catalytic distillation tower 02 is fixedly connected with the flange and the secondary reaction spray tower 15 through a pipeline, specifically, the output end of the methylal refining tower 05 is fixedly connected with the methylal replenishing pipe 005 through the auxiliary pipeline and the flange, the circumferential outer wall of the auxiliary pipeline is connected with a pipeline through the flange, the pipeline is fixedly connected with the secondary reaction spray tower 15, the output end of the secondary reaction spray tower 15 is connected with the cooler 17 through the pipeline and the flange, the output end of the cooler 17 is fixedly connected with the input end of the secondary reaction spray tower 15 through the pipeline and the flange, the catalytic distillation tower 02 is divided into a stripping section, a reaction section and a distillation section, the secondary reaction spray tower 15 is packed with a catalyst, the reactants are converted in the spray absorption process, the packing is a regular wire mesh packing, float valve column plate or bubble cap board, regular silk screen packing, catalyst with 60 ~ 100 mesh stainless steel net parcel with 1: 5 to 1: the structured packing is uniformly filled with the structured packing in a volume ratio of 10, the cooler 17 is a plate heat exchanger with a compact structure, the heat exchange area is 100-500 square meters, and the cooling medium is circulating cooling water.

When the catalytic rectifying tower is used specifically, firstly, 004 gas phase at the top of the catalytic rectifying tower enters a methylal rectifying tower 05 to prevent formaldehyde from condensing, polymerizing and blocking a condenser, the operating temperature of pressure rectification is higher than the critical temperature of the formaldehyde, and a pressure-variable rectification mode is adopted, wherein the preferable operating pressure is 0.1-0.8 MPa; the temperature is 90-180 ℃, and the number of theoretical plates is 25-50; the operation temperature at the top of the tower is 90-120 ℃; the reflux ratio is 0.2-4, unreacted methanol and a small amount of water formaldehyde respectively enter a methylal refining tower 05 through a gas phase outlet at the top of a catalytic rectification tower top 004 and a gas phase outlet at the top of a secondary reaction spray tower 15, and are extracted from a tower kettle and sent to a methylal synthesis tower, wherein the temperature of the tower kettle of a stripping section tower is controlled to be 60-90 ℃, the temperature of the tower top of a rectifying section tower is 40-45 ℃, and the operating temperature of a reaction section of the catalytic rectification tower 02 is 60-90 ℃; the mass ratio of the amount of the formaldehyde supplemented to the feed formaldehyde in the reaction section is preferably 1-5: 1.

Synthesize above, this kind of synthesizer for gathering methoxy dimethyl ether, this utility model is to the principle that the reaction cascade goes on, will contain partial dmm 2's reaction liquid component and take out from catalytic rectification tower and send to the pressure swing rectifying column, and the pressure swing rectifying column top obtains the component that contains dmm2 and formaldehyde, and this strand of gaseous phase component further reacts in second grade reaction spraying system and converts into the reaction liquid of dmm3-5 of higher degree of polymerization. Pumping to a pressure swing distillation tower for further separation, wherein Dmm2 is only used as an intermediate component in the process flow and finally participates in the synthesis of Dmm3-5, a small amount of lost Dmm2 enters a methylal unit and is decomposed into formaldehyde and methylal on a catalyst, the process is compact and simple, and a product with the polymerization degree of 3-5 can be selected in a targeted manner.

While the invention has been described above with reference to an embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, as long as there is no structural conflict, the various features of the disclosed embodiments of the present invention can be used in any combination with each other, and the description of such combinations is not exhaustive in the present specification only for the sake of brevity and resource conservation. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A synthesizer for polyoxymethylene dimethyl ethers is characterized in that: comprises a catalytic rectification tower (02), a methylal rectification tower (05), a catalytic rectification tower kettle (11) and a secondary reaction spray tower (15), wherein the output end of the catalytic rectification tower (02) is fixedly connected with the secondary reaction spray tower (15) through a pipeline and a flange, the methylal rectification tower (05) is connected with the catalytic rectification tower kettle (11), the secondary reaction spray tower (15) is fixedly connected with the input end of the catalytic rectification tower (02) through a flange, a pumping pipe is connected with the input end of the catalytic rectification tower (02) through a flange, a pre-reactor (01) is connected with the input end of the pre-reactor (01) through a flange, a formaldehyde pipe (001) and a methylal pipe (002) are connected with the output end of the catalytic rectification tower (02) through a pipeline and a flange, the output end of the catalytic rectification tower top (004) is fixedly connected with the input end of the methylal rectification tower (05) through a pipeline and a flange, the input end of the catalytic distillation tower (02) is connected with a methylal replenishing pipe (005) through a pipeline and a flange, the output end of the catalytic distillation tower (02) is connected with the input end of a catalytic distillation tower kettle (11) through a main pipeline and a flange, the circumference outer wall of the main pipeline is connected with a pipeline through a flange, the output end of the pipeline is connected with a cooler (17) through a flange, the output end of a secondary reaction spray tower (15) is connected with a secondary reaction spray tower top (010) through a pipeline and a flange, the output end of the secondary reaction spray tower top (010) is fixedly connected with the methylal refining tower (05) through a pipeline and a flange, the output end of the catalytic distillation tower kettle (11) is connected with a tower top pressure control valve (14) through a pipeline and a flange, the output end of the tower top pressure control valve (14) is fixedly connected with the input end of the secondary reaction spray tower (15) through a pipeline and, the input of methylal refined tower (05) has thick methylal pipe (016) through flange connection, the output of thick methylal pipe (016) pass through the flange with second grade reaction sprays top of the tower (010) fixed connection, the output of methylal refined tower (05) pass through auxiliary pipe and flange with methylal additional tube (005) fixed connection, the circumference outer wall of auxiliary pipe has the pipeline through flange connection, the pipeline with second grade reaction spray tower (15) fixed connection, the output of second grade reaction spray tower (15) has cooler (17) through pipeline and flange connection, the output of cooler (17) pass through pipeline and flange with the input fixed connection of second grade reaction spray tower (15).

2. The synthesis device for polyoxymethylene dimethyl ethers according to claim 1, wherein: the catalytic distillation tower (02) is divided into a stripping section, a reaction section and a distillation section.

3. The synthesis device for polyoxymethylene dimethyl ethers according to claim 1, wherein: the secondary reaction spray tower (15) is provided with a packing wrapped with a catalyst, reactants are converted in the spray absorption process, the packing is a regular wire mesh packing, a float valve tower plate or a bubble cap plate, the regular wire mesh packing is adopted, and the catalyst is wrapped with a 60-100-mesh stainless steel wire mesh to form a layer of a mixture with the weight of 1: 5 to 1: the volume ratio of 10 is uniformly filled in the middle of the structured packing.

4. The synthesis device for polyoxymethylene dimethyl ethers according to claim 1, wherein: the number of theoretical plates of the methylal refining tower (05) is 20-60.

5. The synthesis device for polyoxymethylene dimethyl ethers according to claim 1, wherein: the cooler (17) is a plate heat exchanger with a compact structure, the heat exchange area is 100-500 square meters, and the cooling medium is circulating cooling water.