DMMn production equipment

Abstract

The utility model discloses DMMn production equipment, and relates to the technical field of chemical production equipment. The DMMn production equipment comprises a mixer, a DMMn reactor, a hydrogenation reactor, a neutralization reactor, a light component removal tower and a dehydration tower which are connected in sequence and carry out material transfer, the DMMn reactor is used for generating a DMMn crude product; the hydrogenation reactor is used for carrying out hydrogenation reaction on formaldehyde in the DMMn crude product; the neutralization reactor is used for enabling the byproduct formic acid in the material after the hydrogenation reaction to be subjected to neutralization reaction; the light component removal tower is used for removing light components in the material subjected to the neutralization reaction to obtain a DMMn product containing water; the dehydrating tower is used for removing water in the DMMn product containing the water so as to prepare the DMMn product. According to the DMMn production equipment provided by the utility model, a high-purity DMMn product can be prepared, and the consumption of steam in the rectification separation process can be effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of chemical production equipment technology, and in particular to a DMMn production equipment. Background Technology

[0002] Polyoxymethylene dimethyl ether, abbreviated as DMMn, is a new type of clean fuel additive with advantages such as reducing combustion smoke generation, improving combustion performance, and reducing exhaust emissions, and has broad application prospects in the energy and environmental protection fields.

[0003] Formaldehyde and methylal react in a reactor to produce DMMn. The resulting crude DMMn contains light components such as methylal, which need to be separated and purified by distillation in a light component removal column to obtain a higher purity DMMn product. However, the existing crude DMMn contains a large amount of light components such as methylal, requiring a significant amount of steam to be consumed during the distillation process, thus increasing energy consumption. Utility Model Content

[0004] The main purpose of this invention is to propose a DMMn production equipment that aims to solve the problem that existing DMMn production equipment requires a large amount of steam during distillation and separation.

[0005] A DMMn production apparatus includes a mixer, a DMMn reactor, a hydrogenation reactor, a light-light product removal tower, and a dehydration tower connected in sequence for material transfer;

[0006] The mixer is equipped with a formaldehyde inlet and a methyl acetal inlet; the mixer is used for premixing raw materials.

[0007] The feed end of the DMMn reactor is connected to the discharge end of the mixer;

[0008] The hydrogenation reactor is equipped with a crude DMMn feed inlet and a hydrogen inlet at the feed end, which is used to enable the formaldehyde in the crude DMMn to undergo a hydrogenation reaction.

[0009] The feed end of the light component removal tower is provided with a feed inlet for removing light components from the material;

[0010] The dehydration tower is equipped with a DMMn light material inlet and an azeotropic agent inlet at the feed end for removing moisture from the DMMn product.

[0011] In one embodiment, the space velocity of the DMMn reactor is 1000–4000 h⁻¹. -1 The space velocity of the hydrogenation reactor is 1–3 h⁻¹. -1 .

[0012] In one embodiment, the DMMn reactor is a fixed-bed reactor; the hydrogenation reactor is a fixed-bed reactor.

[0013] In one embodiment, the DMMn production equipment further includes a neutralization reactor located on the material transfer path between the DMMn reactor and the hydrogenation reactor, or on the material transfer path between the hydrogenation reactor and the light-weight removal tower.

[0014] In one embodiment, a cooler and a gas-liquid separator are further provided between the hydrogenation reactor and the neutralization reactor. After the hydrogenation reaction, the material is cooled by the cooler (e.g., to 25°C) and then enters the gas-liquid separator. The separated hydrogen can be collected for recycling, and the separated liquid contains almost no formaldehyde but contains the byproduct formic acid, which is then sent to the neutralization reactor.

[0015] In one embodiment, an azeotropic agent inlet is provided in the middle of the dehydration tower to replenish the azeotropic agent when it is depleted or the circulation volume is insufficient.

[0016] In one embodiment, the dehydration tower has a condensation section at its top, which includes a condenser, a reflux tank, and a reflux pipe connected in sequence. The feed end of the condenser is connected to the steam outlet at the top of the dehydration tower via a pipe, and a reflux pump is installed on the reflux pipe. The liquid inlet end of the reflux pipe extends into the middle of the reflux tank, and the liquid outlet end of the reflux pipe is connected to the material reflux port at the top of the dehydration tower. A drain pipe is installed at the bottom of the reflux tank.

[0017] In one embodiment, a flow regulating valve is provided on the drain pipe.

[0018] In one embodiment, a DMMn product collection pipe is provided at the bottom of the dehydration tower.

[0019] In one embodiment, the alkaline feed inlet of the neutralization reactor is higher than the DMMn hydrogenation feed inlet.

[0020] In one embodiment, the light-weight removal tower and the dehydration tower are plate towers or packed towers.

[0021] In one embodiment, the DMMn reactor is provided with an acidic resin catalyst; the hydrogenation reactor is provided with a copper-based catalyst.

[0022] This invention relates to a process for preparing DMMn by reacting formaldehyde aqueous solution with methylal. The preferred raw materials are a formaldehyde aqueous solution with a concentration of 70-90 wt% and methylal with a concentration of over 90 wt%. It is particularly suitable for cases with a small proportion of methylal, for example, a molar ratio of formaldehyde to methylal of (0.5-5):1, where n = 2-8. In this reaction system, the amount of methylal used is relatively small, while the amount of formaldehyde is relatively large, resulting in a low methylal content in the post-reaction material. Compared to common DMMn production systems in the prior art, a distillation column can be omitted. The post-reaction material directly enters a hydrogenation reactor, where formaldehyde is hydrogenated to produce methanol, reducing the impact of formaldehyde on product separation.

[0023] The hydrogenation reaction solution and alkaline materials (such as sodium hydroxide and organic amines) are fed into the neutralization reactor. Inside the neutralization reactor, formic acid undergoes a neutralization reaction with the alkaline materials to remove the byproduct formic acid. The neutralized material is then sent to the light-weight removal tower. The neutralization reactor can also be located on the material transfer route between the DMMn reactor and the hydrogenation reactor; that is, the materials for the synthesis reaction are first neutralized before undergoing the hydrogenation reaction. Both methods are equally effective.

[0024] The neutralized material enters the light component removal tower to separate small amounts of light components such as methylal and methanol from the product. Under atmospheric pressure distillation, the light components are collected from the top of the light component removal tower, while the bottom product contains DMMn and moisture. The bottom product is then sent to the dehydration tower.

[0025] The DMMn product containing moisture enters the dehydration tower, where an azeotropic agent (e.g., cyclohexane) is added. The product undergoes atmospheric distillation. The azeotropic agent and water vapor at the top of the tower pass through a condenser and then into a reflux tank. In the reflux tank, the azeotropic agent and water separate into two phases. The oil phase, being a lighter component, is pressurized by a reflux pump and returned to the dehydration tower. The lower part of the reflux tank contains wastewater, which is sent for wastewater treatment. The bottom of the dehydration tower contains almost water-free DMMn product.

[0026] The DMMn production equipment provided by this utility model can reduce the reliance on distillation columns compared with the prior art. By using a combination of DMMn reactor, hydrogenation reactor, neutralization reactor, light component removal column and dehydration column, high-purity DMMn products can be obtained, and the steam consumption during distillation separation can be effectively reduced. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 A schematic diagram of an embodiment of the DMMn production equipment provided by this utility model.

[0029] Explanation of icon numbers:

[0030] 1. Mixer; 2. DMMn reactor; 3. Hydrogenation reactor; 31. Cooler; 32. Gas-liquid separator; 4. Neutralization reactor; 5. Light weight removal tower; 6. Dehydration tower; 61. Condenser; 62. Reflux tank; 621. Drain pipe; 63. Reflux pipe; 64. Reflux pump; 65. DMMn product collection pipe.

[0031] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0033] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0034] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0035] Formaldehyde and methylal react in a reactor to produce DMMn. The resulting crude DMMn contains light components such as methylal, which need to be separated and purified by distillation in a light component removal column to obtain a higher purity DMMn product. Currently, the crude DMMn contains a significant amount of light components such as methylal, requiring separation using distillation equipment. This distillation process consumes a large amount of steam, increasing energy consumption.

[0036] In view of this, the present invention proposes a DMMn production equipment to solve the problem that existing DMMn production equipment requires a large amount of steam to be consumed during distillation and separation.

[0037] Please see Figure 1 In one embodiment of this utility model, the DMMn production equipment includes a DMMn reactor 2, a hydrogenation reactor 3, a neutralization reactor 4, a light component removal tower 5, and a dehydration tower 6 connected in sequence. The DMMn reactor 2 is used to generate crude DMMn; the hydrogenation reactor 3 is used to hydrogenate formaldehyde in the crude DMMn; the neutralization reactor 4 is used to neutralize formic acid, a byproduct of the hydrogenation reaction, in the material after the hydrogenation reaction; the light component removal tower 5 is used to remove light components from the material after the neutralization reaction to obtain a DMMn product containing moisture; and the dehydration tower 6 is used to remove moisture from the DMMn product containing moisture to obtain the DMMn product.

[0038] In this invention, a formaldehyde aqueous solution with a concentration of 70-90 wt% and methylal with a concentration of over 90 wt% are mixed in mixer 1 and then fed into DMMn reactor 2. The molar ratio of formaldehyde to methylal in the feed is (0.5-5):1. Formaldehyde and methylal react to generate DMMn, where n = 2-8. The reacted material is then sent for hydrogenation.

[0039] The reacted material and hydrogen are fed into hydrogenation reactor 3. In hydrogenation reactor 3, formaldehyde is hydrogenated to produce methanol. Hydrogenation is used to purify the crude product, so that formaldehyde is converted into methanol, reducing the impact of formaldehyde on product separation. After being cooled by cooler 31, the material after hydrogenation reaction enters gas-liquid separator 32. The separated hydrogen can be collected for recycling, and the separated liquid is sent to neutralization reactor 4.

[0040] The hydrogenation reaction liquid and alkaline materials (sodium hydroxide or organic amine) are fed into neutralization reactor 4. In neutralization reactor 4, the temperature is controlled at 60-150℃. Formic acid and sodium hydroxide undergo a neutralization reaction to remove the byproduct formic acid. The material after neutralization is sent to light-weight removal tower 5.

[0041] The neutralized material enters the light component removal tower 5 to separate light components such as methylal and methanol from the product. Under atmospheric pressure distillation, the light components are collected from the top of the light component removal tower 5, while the bottom product contains DMMn and moisture. The bottom product is sent to the dehydration tower 6.

[0042] The DMMn product containing moisture enters dehydration tower 6, where an azeotropic agent, cyclohexane, is added. The product undergoes atmospheric distillation. The azeotropic agent and water vapor at the top of the tower enter condenser 61 and then reflux tank 62. The azeotropic agent and water separate into phases in reflux tank 62. The oil phase, being a lighter component, is pressurized by reflux pump 64 and returned to dehydration tower 6. The lower part of reflux tank 62 contains wastewater, which is sent for wastewater treatment. The bottom of dehydration tower 6 contains almost water-free DMMn product.

[0043] The dehydration tower 6 includes a rectification section and a stripping section. A DMMn light material inlet and an azeotropic agent inlet are located in the middle of the dehydration tower 6. A condensation section is located at the top of the dehydration tower 6, comprising a condenser 61, a reflux tank 62, and a reflux pipe 63 connected in sequence. The feed end of the condenser 61 is connected to the steam outlet at the top of the dehydration tower 6. A reflux pump 64 is installed on the reflux pipe 63. The liquid inlet of the reflux pipe 63 extends into the middle of the reflux tank 62, and the liquid outlet of the reflux pipe 63 is connected to the material reflux port at the top of the dehydration tower 6. A drain pipe 621 is located at the bottom of the reflux tank 62.

[0044] By adopting the above technical solution, the DMMn product containing moisture and the azeotropic agent cyclohexane enter the dehydration tower 6, which is operated under atmospheric pressure distillation. The bottom temperature of the tower is 110-120℃, and the top temperature is 60-70℃. The azeotropic agent and water vapor phase at the top of the dehydration tower 6 enter the condenser 61 and then the reflux tank 62. The azeotropic agent and water separate into phases in the reflux tank 62. The oil phase, which is the light component, is pressurized by the reflux pump 64 and returned to the dehydration tower 6. The lower part of the reflux tank 62 contains wastewater, which is sent to the wastewater treatment plant through the drain pipe 621. The bottom of the dehydration tower 6 contains almost water-free DMMn product.

[0045] Specifically, a flow regulating valve is installed on the drain pipe 621; a DMMn product collection pipe 65 is installed at the bottom of the dehydration tower 6. The flow regulating valve on the drain pipe can adjust the flow rate of the drain. The DMMn product in the bottom of the dehydration tower 6 is collected through the DMMn product collection pipe 65.

[0046] In this embodiment of the invention, the upper part of the neutralization reactor 4 is provided with a DMMn hydrogenation material inlet and an alkaline material inlet; the lower part of the neutralization reactor 4 is provided with a neutralization reaction material outlet. The material after the hydrogenation reaction enters the neutralization reactor 4 through the DMMn hydrogenation material inlet, while the alkaline material, such as sodium hydroxide or organic amine, enters the neutralization reactor 4 through the alkaline material inlet. The byproduct formic acid undergoes a neutralization reaction with the alkaline material to remove the formic acid. The material after the neutralization reaction is discharged through the material outlet and sent to the light-weight removal tower 5. The light-weight removal tower 5 operates under atmospheric pressure distillation, with a bottom temperature of 95–100°C and a top temperature of 40–45°C. The feed inlet of the light-weight removal tower 5 is located in the middle of the tower, and the material after the neutralization reaction in the neutralization reactor 4 enters the light-weight removal tower 5 for the light-weight removal reaction.

[0047] Furthermore, the light-weight removal tower 5 and the dehydration tower 6 are plate towers or packed towers; the reflux ratio of the light-weight removal tower 5 and the dehydration tower 6 is 1 to 5. Specifically, the light-weight removal tower 5 and the dehydration tower 6 are plate towers with an effective number of 30 to 50 plates.

[0048] Furthermore, an acidic resin catalyst is provided in the DMMn reactor 2, and a copper-based catalyst is provided in the hydrogenation reactor 3. Under the conditions of the acidic resin catalyst, the pressure in the DMMn reactor 2 is controlled at 0.5–2.0 MPa and the temperature at 60–120°C, allowing formaldehyde and methylal to react more fully to generate DMMn. Under the conditions of the copper-based catalyst, the pressure in the hydrogenation reactor 3 is controlled at 1.0–2.0 MPa and the temperature at 100–180°C, allowing formaldehyde to react more fully with hydrogen to generate methanol, thereby reducing the impact of formaldehyde on product separation.

[0049] Specifically, an acidic resin catalyst is installed in the middle of the DMMn reactor 2. The acidic resin catalyst can be a sulfonic acid resin catalyst, such as D-009B resin. A material inlet is installed at the top of the DMMn reactor 2. Formaldehyde aqueous solution and methyl acetal enter the DMMn reactor through the material inlet. The reacted material in the DMMn reactor 2 is discharged from the bottom of the DMMn reactor 2 and enters the hydrogenation reactor 3.

[0050] A copper-based catalyst is installed in the middle of the hydrogenation reactor 3. The copper-based catalyst can be a manganese-modified copper catalyst, such as Mn-CZ / SBA-15 catalyst. The upper part of the hydrogenation reactor 3 is equipped with a DMMn crude product inlet and a hydrogen inlet. The material after the reaction in the DMMn reactor enters the hydrogenation reactor 3 through the DMMn crude product inlet, and the hydrogen enters the hydrogenation reactor 3 through the hydrogen inlet. The material after the hydrogenation reaction is discharged from the bottom of the hydrogenation reactor 3 and enters the cooler 31.

[0051] Using the production equipment of this application, the product energy consumption can reach 2t steam / t product, while the average energy consumption of existing processes is 7-8t steam / t product, and the better processes can reach 5-6t steam / t product. The production equipment of this application has a significant energy consumption reduction effect.

[0052] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A DMMn production equipment, characterized in that, It includes a mixer, a DMMn reactor, a hydrogenation reactor, a light-weight removal tower, and a dehydration tower that are connected in sequence and transfer materials. The mixer is equipped with a formaldehyde inlet and a methyl acetal inlet; The feed end of the DMMn reactor is connected to the discharge end of the mixer; The hydrogenation reactor is equipped with a crude DMMn feed inlet and a hydrogen inlet at the feed end, which is used to enable the formaldehyde in the crude DMMn to undergo a hydrogenation reaction. The feed end of the light component removal tower is provided with a feed inlet for removing light components from the material; The dehydration tower is equipped with a DMMn light material inlet and an azeotropic agent inlet at the feed end for removing moisture from the DMMn product.

2. The DMMn production equipment as described in claim 1, characterized in that, The space velocity of the DMMn reactor is 1000–4000 h⁻¹. -1 The space velocity of the hydrogenation reactor is 1–3 h⁻¹. -1 .

3. The DMMn production equipment as described in claim 1, characterized in that, The DMMn reactor is a fixed-bed reactor; the hydrogenation reactor is a fixed-bed reactor.

4. The DMMn production equipment as described in claim 1, characterized in that, An azeotropic agent inlet is provided in the middle of the dehydration tower.

5. The DMMn production equipment as described in claim 1, characterized in that, The dehydration tower has a condensation section at the top, which includes a condenser, a reflux tank, and a reflux pipe connected in sequence. The feed end of the condenser is connected to the steam outlet at the top of the dehydration tower via a pipe. A reflux pump is installed on the reflux pipe. The liquid inlet end of the reflux pipe extends into the middle of the reflux tank, and the liquid outlet end of the reflux pipe is connected to the material reflux port at the top of the dehydration tower. A drain pipe is installed at the bottom of the reflux tank.

6. The DMMn production equipment as described in claim 1, characterized in that, The DMMn production equipment also includes a neutralization reactor, which is located on the material transfer path between the DMMn reactor and the hydrogenation reactor, or on the material transfer path between the hydrogenation reactor and the light-light-removal tower.

7. The DMMn production equipment as described in claim 6, characterized in that, The alkaline feed inlet of the neutralization reactor is higher than the DMMn hydrogenation feed inlet.

8. The DMMn production equipment as described in claim 1, characterized in that, The bottom of the dehydration tower is equipped with a DMMn product collection pipe.

9. The DMMn production equipment as described in claim 1, characterized in that, The light-weight removal tower and the dehydration tower are plate towers or packed towers.

10. The DMMn production equipment as described in claim 1, characterized in that, The DMMn reactor is equipped with an acidic resin catalyst; the hydrogenation reactor is equipped with a copper-based catalyst.

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