阅读说明：本技术 一种回收废亚克力制备mma单体的方法及系统 (Method and system for preparing MMA (methyl methacrylate) monomer by recycling waste acrylic ) 是由 吴相廉 于 2020-06-04 设计创作，主要内容包括：本发明公开了一种回收废亚克力制备MMA单体的方法及系统,属于有机玻璃废料再利用技术领域。所述方法包括回收亚克力经粉碎、裂解、冷凝和蒸馏得到MMA单体；所述蒸馏工序为：经冷凝得到的MMA粗品在不带填料的粗馏塔中粗馏2-4小时,馏分再送至中间储罐中静置2-5小时并去除水层,最后于填装有填料的精馏塔中精馏8-12小时,所述粗馏塔的高度为8-10米,所述精馏塔的高度为15-20米,粗馏温度为40-70℃,精馏温度为60-65℃。可得到纯度95-97%的MMA单体,以单体制备的亚克力白度高；同时,以20立方的精馏釜为例,可得到18.3立方馏分,提升了生产效率(粗馏与精馏可同时进行)。(The invention discloses a method and a system for preparing MMA monomers by recycling waste acrylic, and belongs to the technical field of organic glass waste recycling. The method comprises the steps of recovering acrylic acid, crushing, cracking, condensing and distilling to obtain an MMA monomer; the distillation process comprises the following steps: crude MMA obtained by condensation is subjected to crude distillation for 2-4 hours in a crude distillation tower without filler, the distillate is sent to an intermediate storage tank again to be kept stand for 2-5 hours and a water layer is removed, and finally the crude MMA is subjected to rectification for 8-12 hours in a rectification tower filled with filler, wherein the height of the crude distillation tower is 8-10 meters, the height of the rectification tower is 15-20 meters, the crude distillation temperature is 40-70 ℃, and the rectification temperature is 60-65 ℃. The MMA monomer with the purity of 95-97 percent can be obtained, and the whiteness of the acrylic prepared by the monomer is high; meanwhile, taking a 20 cubic rectifying still as an example, 18.3 cubic fractions can be obtained, and the production efficiency is improved (the rough distillation and the rectification can be carried out simultaneously).)

1. A method for preparing MMA monomers by recycling waste acrylic acid comprises the steps of crushing, cracking, condensing and distilling the recycled acrylic acid to obtain MMA monomers; characterized in that the distillation process comprises: crude MMA obtained by condensation is subjected to crude distillation for 2-4 hours in a crude distillation tower without filler, the distillate is sent to an intermediate storage tank again to be kept stand for 2-5 hours and a water layer is removed, and finally the crude MMA is subjected to rectification for 8-12 hours in a rectification tower filled with filler, wherein the height of the crude distillation tower is 8-10 meters, the height of the rectification tower is 15-20 meters, the crude distillation temperature is 40-70 ℃, and the rectification temperature is 60-65 ℃.

2. The method for preparing MMA monomer according to the recycled waste acrylic acid, according to claim 1, wherein the crude distillation column is arranged on a crude distillation still, and the volume of the crude distillation still is 5-7 cubic degrees; the rectifying tower is arranged on a rectifying still, and the volume of the rectifying still is 15-20 cubic.

3. The method for preparing MMA according to claim 1, wherein the condensing process comprises: and (3) carrying out primary condensation on the pyrolysis gas through a primary tube array condenser (1), separating insoluble impurities by using a settling tank (1), carrying out secondary condensation through a secondary tube array condenser (3) and carrying out tertiary condensation through a jacket condenser to obtain an MMA crude product, and filtering the insoluble impurities through a pipeline filter (4) to obtain the MMA crude product.

4. The method for preparing MMA according to claim 3, wherein the condensing process further comprises: the method comprises the following steps that exhaust gas of a storage tank for storing crude MMA is output to a vacuum tank through a vertical condenser vertically arranged on the storage tank, the vacuum tank is output to a water tank in two ways, the exhaust gas is output to one way with a Roots blower when power is off, otherwise, the exhaust gas is output to one way with a water ring vacuum pump, the two ways are both introduced into liquid in the water tank, and gas output by the water tank sequentially passes through a primary oil-water separator, a heat exchange condenser and a secondary oil-water separator and then is sent to a cracking furnace to serve as fuel; the Roots blower is powered by the generator; the heat exchange condenser is positioned in a refrigeration house with the freezing temperature of 10 ℃ or below, the refrigeration house is used as a heat exchange medium, and the output condensate is also an MMA crude product; the water tank supplies water for the water ring vacuum pump, is of a closed box structure, the inner lower part of the water tank is liquid, the inner upper part of the water tank is gas, and the liquid in the water tank is replaced according to a preset requirement.

5. The method for preparing MMA monomer according to the recycled waste acrylic acid as claimed in claim 1, wherein the crude distillation raffinate of the crude distillation tower is sent to the cracking process, and the rectification raffinate of the rectification tower is sent to the crude distillation tower for crude distillation.

6. The method for preparing MMA monomer according to claim 1, wherein the packing of the rectification column is stainless steel packing or ceramic packing, and the reflux ratio during rectification is 1:1-1: 4.

7. A system for preparing MMA monomers by recycling waste acrylic comprises a cracking furnace, a condensing device, a storage tank and a rectifying device, wherein the cracking furnace, the condensing device and the storage tank are sequentially connected through a pipeline; the rectification device comprises a rectification tower filled with filler, a rectification condenser, a rectification gas-water separator, a rectification buffer tank, a finished product condenser and a finished product storage tank, wherein a rectification kettle is arranged at the bottom of the rectification tower, the rectification condenser, the rectification gas-water separator and the rectification buffer tank are sequentially connected through a pipeline, the rectification buffer tank is output in two ways, one way is output to a reflux port of the rectification tower through the pipeline, and the other way is output to an inlet of the finished product condenser through the pipeline; the outlet of the finished product condenser is connected with a finished product storage tank through a pipeline; the system is characterized by further comprising a rough distillation device, wherein the rough distillation device comprises a rough distillation tower, a rough distillation condenser, a rough distillation gas-water separator, a rough distillation buffer tank and an intermediate storage tank which are sequentially connected through pipelines and do not have filler, a rough distillation kettle is arranged at the bottom of the rough distillation tower, the storage tank is connected with the rough distillation kettle through a pipeline, and an oil phase outlet of the intermediate storage tank is connected with the rectification kettle through a pipeline.

8. The system for preparing MMA according to claim 7, wherein the height of the crude distillation column is 8-10 m, the height of the rectification column is 15-20 m, the volume of the crude distillation still is 5-7 cubic, the volume of the rectification still is 15-20 cubic, and the packing of the rectification column is stainless steel packing or ceramic packing.

9. The system for recycling waste acrylic acid to prepare MMA monomers according to claim 7, wherein the condensing device comprises a pipeline filter (4), and a primary tubular condenser (1), a settling tank (2), a secondary tubular condenser (3) and a jacket condenser which are sequentially connected through a pipeline, a sediment outlet of the settling tank (2) is connected with a storage tank through a pipeline with a first valve (6) and the pipeline filter (4), an inlet of the primary tubular condenser (1) is connected with the cracking furnace through a pipeline, and an outlet of the jacket condenser is connected with the storage tank through a pipeline.

10. The system for recycling waste acrylic to prepare MMA monomer according to claim 9, wherein the storage tank is a horizontal storage tank;

the condensing device also comprises a vertical condenser, a vacuum tank, a water ring vacuum pump, a water tank for supplying water to the water ring vacuum pump, a primary oil-water separator, a secondary oil-water separator, a cold storage, a Roots blower, a generator for supplying power to the Roots blower and a heat exchange condenser in the cold storage;

the water tank is of a closed tank structure, the inner lower part of the water tank is liquid, and the inner upper part of the water tank is gas;

the vertical condenser is arranged on an exhaust port of the material storage tank along the vertical direction, an outlet at the top end of the vertical condenser is connected with an air inlet of the vacuum tank through a pipeline, an air outlet of the vacuum tank is output into liquid of the water tank in two ways and is gated through a valve, a water ring vacuum pump is arranged on one way, and a Roots blower is arranged on the other way; the gas outlet on the upper part of the water tank, the primary oil-water separator, the heat exchange condenser, the secondary oil-water separator and the combustion chamber of the cracking furnace are sequentially connected through pipelines, and the heat exchange condenser takes a refrigeration house as a heat exchange medium and is provided with a condensate outlet at the bottom.

Technical Field

The invention belongs to the technical field of organic glass waste recycling, and particularly relates to a method and a system for preparing MMA monomers by recycling waste acrylic.

Background

Acrylic is light, beautiful and tough, is easy to clean, is easy to process, has beautiful color, higher surface hardness and luster, good chemical corrosion resistance, high transparency and stable surface wear resistance close to the physical property of aluminum products, is called as 'plastic queen', and is widely applied to buildings, chemical engineering, industry, advertisements and the like.

The acrylic plate, namely the polymethyl methacrylate plate, is polymerized by methyl methacrylate monomer. One of the existing acrylic plates is called a recycled regeneration plate, which is obtained by utilizing recycled acrylic leftover materials, obtaining a regenerated methyl methacrylate monomer through thermal degradation and then carrying out chemical polymerization reaction. The production method has low input cost and is beneficial to environmental protection.

For example, patent with application number CN201910328678.5 discloses a process flow of an acrylic cracking recovery device, which comprises the following steps:

(1) discharging: and (3) putting the waste acrylic into a hopper, and feeding the waste acrylic into a feeding roller along the hopper.

(2) Conveying materials: the second motor is started, the second motor drives the feeding roller to rotate, and the waste acrylic raw material moves forwards along the external threads of the feeding roller due to the rotation of the feeding roller.

(3) Turning over the roller: the material is prevented by the cooling sleeve from melting without entering the roller, the first motor is started to drive the chain to rotate and the chain wheel to rotate, so that the left roller is rotated to drive the roller to rotate, and the rotating wheel and the auxiliary rotating wheel are arranged outside the left roller to assist in rotation.

(4) Smoke discharging and condensation: the material is cracked into PMMA gas and coke after passing through the roller furnace, and the PMMA gas is introduced into a condensing device through a smoke outlet pipe to be condensed.

For example, patent No. CN 201811558448. X discloses a method for preparing MMA monomer by continuously cracking acrylic, which comprises:

(1) and (3) crushing the acrylic into particles with the particle size less than 20mm to obtain the granular material.

(2) Adding the granular materials into a first heating pipe through a feeding port, conveying the granular materials to a second heating pipe through a screw, and continuously heating the granular materials through a heating device in the conveying process to ensure that the temperature of the granular materials at an outlet of the first heating pipe is 200-300 ℃; and the air mixed in the granular materials is discharged through the first air outlet pipe in the conveying process.

(3) Maintaining the temperature in the second heating pipe to be 500-600 ℃ through a heating device of the second heating pipe, conveying the granular materials obtained in the step (2) by adopting a screw, continuously pyrolyzing the granular materials in the conveying process, and collecting MMA monomer steam obtained by pyrolysis through second air outlet pipes connected to different positions of the second heating pipe; the non-pyrolyzed granules were transported to a vertical gas permeable tube by a screw.

(4) The non-pyrolyzed granular materials enter a third heating pipe through the vertical ventilation pipe, the temperature in the third heating pipe is maintained at 400-500 ℃, and the non-pyrolyzed granular materials are conveyed by a screw rod so as to be pyrolyzed continuously; collecting MMA monomer steam obtained by cracking through third air outlet pipes arranged at different positions of a third heating pipe.

(5) Collecting MMA monomer steam collected in the step (3) and the step (4) into an air outlet header, wherein the second air outlet pipe and the third air outlet pipe are connected into the air outlet header; and carrying out primary condensation through a water-cooling branch pipe connected with the air outlet collecting pipe, and carrying out secondary condensation through a liquid nitrogen cooling mechanism to obtain an MMA monomer finished product.

Disclosure of Invention

In order to solve the above problems, embodiments of the present invention provide a method and a system for preparing an MMA monomer by recycling waste acrylic, which can obtain an MMA monomer with a purity of 95-97%, and the whiteness of the acrylic prepared by the monomer is high; meanwhile, taking a 20 cubic rectifying still as an example, 18.3 cubic fractions can be obtained, and the production efficiency is improved (the rough distillation and the rectification can be carried out simultaneously). The technical scheme is as follows:

in one aspect, the embodiment of the invention provides a method for preparing an MMA monomer by recycling waste acrylic acid, which comprises the steps of crushing, cracking, condensing and distilling the recycled acrylic acid to obtain the MMA monomer; the distillation process comprises the following steps: crude MMA obtained by condensation is subjected to crude distillation for 2-4 hours in a crude distillation tower without filler, the distillate is sent to an intermediate storage tank again to be kept stand for 2-5 hours and a water layer is removed, and finally the crude MMA is subjected to rectification for 8-12 hours in a rectification tower filled with filler, wherein the height of the crude distillation tower is 8-10 meters, the height of the rectification tower is 15-20 meters, the crude distillation temperature is 40-70 ℃, and the rectification temperature is 60-65 ℃.

Further, the crude distillation tower in the embodiment of the invention is arranged on a crude distillation kettle, and the volume of the crude distillation kettle is 5-7 cubic meters; the rectifying tower is arranged on a rectifying still, and the volume of the rectifying still is 15-20 cubic.

Wherein, the condensation process in the embodiment of the invention is as follows: and (3) carrying out primary condensation on the pyrolysis gas by using a primary tube array condenser 1, separating insoluble impurities by using a settling tank 2, carrying out secondary condensation by using a secondary tube array condenser 3, carrying out tertiary condensation by using a jacket condenser to obtain an MMA crude product, and filtering the insoluble impurities by using a pipeline filter 4 to obtain the MMA crude product.

Preferably, the condensation process in the embodiment of the present invention further includes: the method comprises the following steps that exhaust gas of a storage tank for storing crude MMA is output to a vacuum tank through a vertical condenser vertically arranged on the storage tank, the vacuum tank is output to a water tank in two ways, the exhaust gas is output to one way with a Roots blower when power is off, otherwise, the exhaust gas is output to one way with a water ring vacuum pump, the two ways are both introduced into liquid in the water tank, and gas output by the water tank sequentially passes through a primary oil-water separator, a heat exchange condenser and a secondary oil-water separator and then is sent to a cracking furnace to serve as fuel; the Roots blower is powered by the generator; the heat exchange condenser is positioned in a refrigeration house with the freezing temperature of 10 ℃ or below, the refrigeration house is used as a heat exchange medium, and the output condensate is also an MMA crude product; the water tank supplies water for the water ring vacuum pump, is of a closed box structure, the inner lower part of the water tank is liquid, the inner upper part of the water tank is gas, and the liquid in the water tank is replaced according to a preset requirement.

Further, the crude distillation residual liquid of the crude distillation tower in the embodiment of the invention is sent to a cracking process, and the rectification residual liquid of the rectification tower is sent to the crude distillation tower for crude distillation.

The packing of the rectifying tower in the embodiment of the invention is stainless steel packing or ceramic packing, and the reflux ratio during rectification is 1:1-1: 4.

On the other hand, the embodiment of the invention provides a system for preparing MMA monomers by recycling waste acrylic acid, which comprises a cracking furnace, a condensing device, a storage tank, a rough distillation device and a rectification device, wherein the cracking furnace, the condensing device and the storage tank are sequentially connected through a pipeline; the rectification device comprises a rectification tower filled with filler, a rectification condenser, a rectification gas-water separator, a rectification buffer tank, a finished product condenser and a finished product storage tank, wherein a rectification kettle is arranged at the bottom of the rectification tower, the rectification condenser, the rectification gas-water separator and the rectification buffer tank are sequentially connected through a pipeline, the rectification buffer tank is output in two ways, one way is output to a reflux port of the rectification tower through the pipeline, and the other way is output to an inlet of the finished product condenser through the pipeline; the outlet of the finished product condenser is connected with a finished product storage tank through a pipeline; the device comprises a coarse distillation tower, a coarse distillation condenser, a coarse distillation gas-water separator, a coarse distillation buffer tank and an intermediate storage tank which are sequentially connected through pipelines and do not have filler, wherein a coarse distillation kettle is arranged at the bottom of the coarse distillation tower, the storage tank is connected with the coarse distillation kettle through a pipeline, and an oil phase outlet of the intermediate storage tank is connected with the rectification kettle through a pipeline.

The height of the crude distillation tower in the embodiment of the invention is 8-10 m, the height of the rectification tower is 15-20 m, the volume of the crude distillation kettle is 5-7 cubic, the volume of the rectification kettle is 15-20 cubic, and the packing of the rectification tower is stainless steel packing or ceramic packing.

The condensing device comprises a pipeline filter 4, and a primary tube array condenser 1, a settling tank 2, a secondary tube array condenser 3 and a jacket condenser which are sequentially connected through a pipeline, wherein a sediment outlet of the settling tank 2 is connected with a material storage tank through a pipeline with a first valve 6 and the pipeline filter 4, an inlet of the primary tube array condenser 1 is connected with a cracking furnace through a pipeline, and an outlet of the jacket condenser is connected with the material storage tank through a pipeline.

Preferably, the storage tank in the embodiment of the invention is a horizontal storage tank; the condensing device also comprises a vertical condenser, a vacuum tank, a water ring vacuum pump, a water tank for supplying water to the water ring vacuum pump, a primary oil-water separator, a secondary oil-water separator, a cold storage, a Roots blower, a generator for supplying power to the Roots blower and a heat exchange condenser in the cold storage; the water tank is of a closed tank structure, the inner lower part of the water tank is liquid, and the inner upper part of the water tank is gas; the vertical condenser is arranged on an exhaust port of the material storage tank along the vertical direction, an outlet at the top end of the vertical condenser is connected with an air inlet of the vacuum tank through a pipeline, an air outlet of the vacuum tank is output into liquid of the water tank in two ways and is gated through a valve, a water ring vacuum pump is arranged on one way, and a Roots blower is arranged on the other way; the gas outlet on the upper part of the water tank, the primary oil-water separator, the heat exchange condenser, the secondary oil-water separator and the combustion chamber of the cracking furnace are sequentially connected through pipelines, and the heat exchange condenser takes a refrigeration house as a heat exchange medium and is provided with a condensate outlet at the bottom.

The technical scheme provided by the embodiment of the invention has the following beneficial effects: the embodiment of the invention provides a method and a system for preparing an MMA monomer by recycling waste acrylic, the MMA monomer with the purity of 95-97% can be obtained, and the whiteness of the acrylic prepared by the monomer is high; meanwhile, taking a 20 cubic rectifying still as an example, 18.3 cubic fractions can be obtained, and the production efficiency is improved (the rough distillation and the rectification can be carried out simultaneously).

Drawings

FIG. 1 is a schematic block diagram of a system for preparing MMA monomer by recycling waste acrylic according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a condensing unit according to an embodiment of the present invention;

fig. 3 is a schematic diagram of the construction of the settling tank and pipe filter combination.

In the figure: the system comprises a primary tubular condenser 1, a settling tank 2, a secondary tubular condenser 3, a pipeline filter 4, a blow-off pipe 5, a first valve 6, a three-way pipe 7, a blow-off valve 8 and a second valve 9.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.