CN219595890U

CN219595890U - Improved DMAC recovery system

Info

Publication number: CN219595890U
Application number: CN202320173118.9U
Authority: CN
Inventors: 魏顺风
Original assignee: Fujian Hengshen Synthetic Fiber Technology Co ltd
Current assignee: Fujian Hengshen Synthetic Fiber Technology Co ltd
Priority date: 2023-02-06
Filing date: 2023-02-06
Publication date: 2023-08-29
Anticipated expiration: 2033-02-06

Abstract

The utility model relates to the field of polymerization production, in particular to an improved DMAC recovery system. The waste DMAC purifying device comprises a waste DMAC collecting tank and a purifying tower, wherein a liquid outlet of the DMAC collecting tank is connected with the purifying tower, and a filter is arranged at the liquid outlet of the DMAC collecting tank. The utility model utilizes the pressure difference between the inside and the outside of the refining tower to reform the recovery device, directly sucks the collected and used crude DMAC into the refining tower for distillation recovery, thereby saving the electric energy consumed by recovering the crude DMAC through the conveying pump and avoiding the pump damage caused by the recovery of the conveying pump.

Description

Improved DMAC recovery system

Technical Field

The utility model relates to the field of polymerization production, in particular to an improved DMAC recovery system.

Background

The spandex production needs to use a large amount of DMAC, so that a large amount of waste water containing DMAC can be generated in the use process, and direct discharge can cause great influence on the water quality environment and harm the health of people. Therefore, the recovery and treatment of the DMAC waste liquid are of great significance in the aspects of environmental protection, production cost reduction of enterprises and the like.

Since DMAC does not decompose when heated to boiling at atmospheric pressure, distillation can be performed at atmospheric pressure. In consideration of energy conservation and environmental protection, the used DMAC is generally collected in production and is conveyed into a refining tower through a conveying pump, when the dimethylacetamide is distilled and separated by the refining tower, the dimethylacetamide in liquid is heated and gasified by the refining tower, then the gas of the dimethylacetamide is liquefied by a condenser, and the DMAC liquid is recovered to a DMAC storage tank for recycling through the distillation process.

However, since the crude DMAC is large in amount, and in the polymerization and wire drawing processes, a small amount of chemical substances (such as acid substances, organic alkali substances, catalysts and decomposition products thereof, water, decomposition products of the solvent itself, etc.) and solid impurities (polymers, metal particles, dust particles, etc.) other than the solvent itself may be mixed in the crude solvent under high-temperature and high-pressure operation conditions, and recovered by the transfer pump, the recovery process consumes a large amount of electric energy, and the impurities contained in the crude DMAC easily block the transfer pump, causing pump damage.

Disclosure of Invention

The utility model aims to solve the technical problem of providing an improved DMAC recovery system which is energy-saving and reduces damage to a pump.

The utility model is realized in the following way:

an improved DMAC recovery system comprises a waste DMAC collecting tank and a refining tower, wherein a liquid outlet of the DMAC collecting tank is connected with the refining tower, and a filter is arranged at the liquid outlet of the DMAC collecting tank.

Further, the DMAC holding tank is two or more connected in parallel.

Further, valves are arranged on the branch pipelines connected in parallel, and a main pipeline connected with the DMAC collecting tank and the refining tower is provided with a main valve.

Further, the refining tower is sequentially connected with a precooler and a cryocooler through a gas circulation pipeline, and the precooler and the cryocooler are respectively connected with the refining tower through liquid return pipelines.

Still further, the liquid return line is provided with a reflux discharge pump, the reflux discharge pump is provided with two liquid outlets, one is a reflux outlet connected with the refining tower, and the other is a discharge outlet connected to the DMAC storage tank.

Further, an air outlet of the deep cooler is connected with an exhaust emission system through a water ring vacuum pump.

The utility model has the advantages that: the utility model utilizes the pressure difference between the inside and the outside of the refining tower to reform the recovery device, directly sucks the collected and used crude DMAC into the refining tower for distillation recovery, thereby saving the electric energy consumed by recovering the crude DMAC through the conveying pump and avoiding the pump damage caused by the recovery of the conveying pump.

Drawings

The utility model will be further described with reference to examples of embodiments with reference to the accompanying drawings.

Fig. 1 is a schematic structural view of the present utility model.

The reference numerals in the figures are: DMAC collecting tank 1, filter 11, refining tower 2, precooler 3, chiller 4, reflux intermediate tank 5, reflux discharge pump 6, and water ring vacuum pump 7.

Detailed Description

In the description of the present utility model, it should be understood that the description of indicating the orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description and to simplify the description, rather than to indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the scope of protection of the present utility model.

In the description of the present utility model, it should be noted that, unless explicitly stated and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

The technical scheme of the utility model is as follows:

referring to fig. 1, an improved DMAC recycling system of the present utility model includes a waste DMAC collecting tank 1 and a refining tower 2, where a liquid outlet of the DMAC collecting tank 1 is connected with a tower bottom of the refining tower 2.

The further technical scheme is that two DMAC collecting tanks 1 are connected in parallel through two branch pipelines, valves are arranged on the branch pipelines, and a main pipeline connected with a refining tower 2 is provided with a main valve.

A filter 11 is mounted at the outlet of each DMAC sump 1.

The further technical scheme is that the top air outlet end of the refining tower 2 is connected with a precooler 3 and a cryocooler 4 in sequence, and is connected to a reflux intermediate storage tank 5 through the liquid outlet ends of the precooler 3 and the cryocooler 4 respectively, and then is in circulating connection with the refining tower 2 through a reflux discharge pump 6.

The reflux discharge pump 6 is provided with two discharge ports, one port being refluxed and the other port being connected to a DMAC tank (not shown).

The further technical scheme is that an air outlet of the refrigerator 4 is connected with an exhaust emission system through a water ring vacuum pump 7.

In a specific embodiment, the refining column 2 is a distillation refining column, also known as a rectifying column. The rectifying tower is provided with a certain rectifying column in a distillation mode, so that required substances can be accurately and independently formed into gas phases from various liquid phases, and the purpose of separation is achieved.

The specific operation is as follows:

(1) Through the pipeline transformation, the crude DMAC collecting tank is directly connected with the tower kettle of the refining tower, and a valve and a filter are arranged on a connecting pipeline. In the distillation process of the refining tower, the inside of the tower is negative pressure, and the outside of the tower is positive pressure. And when the waste liquid is recovered, a valve between a collecting tank and a connecting pipeline of the tower kettle of the refining tower is opened, and crude DMAC is sucked into the tower kettle of the refining tower by utilizing the pressure difference between the inside and the outside of the refining tower.

(2) Filtering liquid DMAC containing impurities, then entering a tower kettle, heating the liquid DMAC in the tower kettle through steam, vaporizing the DMAC, pumping vaporized DMAC gas through a vacuum pump, and cooling the liquid DMAC in a precooler and a deep cooler to obtain liquid DMAC; the precooler and the cryocooler are connected in series, the precooler is used for cooling firstly, the gas which is not cooled is left for cooling the cryocooler, then liquid DMAC formed after cooling is collected to a DMAC storage tank for recycling, and the residue left in the tower kettle is discharged through a waste discharge port at the bottom.

(3) The vaporized DMAC gas sequentially passes through a precooler and a cryocooler, the residual tail gas after condensation is a very small amount of impurity gas generated in the distillation process, such as amine and nitrogen, and the impurity gas is discharged into the atmosphere after being passed through a water ring vacuum pump.

(4) The liquid DMAC cooled in the precooler and the cryocooler is partially refluxed into the column bottoms for the purpose of preventing distillation from being too fast.

The utility model has the advantages that no pump is used for recycling, and the pressure difference between the inside and the outside of the tower (negative pressure formed by the suction of the water ring vacuum pump) is fully utilized to suck the DMAC into the tower. Not only reduces the electric energy consumed by recycling the crude DMAC through the delivery pump, but also reduces the use of the pump in the process of recycling the crude DMAC, and avoids the damage of the recycling pump.

While specific embodiments of the utility model have been described above, it will be appreciated by those skilled in the art that the specific embodiments described are illustrative only and not intended to limit the scope of the utility model, and that equivalent modifications and variations of the utility model in light of the spirit of the utility model will be covered by the claims of the present utility model.

Claims

1. An improved DMAC recovery system, characterized by: the waste DMAC collecting tank and the refining tower are included, a liquid outlet of the DMAC collecting tank is connected with the refining tower, and a filter is arranged at the liquid outlet of the DMAC collecting tank;

the refining tower is sequentially connected with a precooler and a cryocooler through a gas circulation pipeline, and the precooler and the cryocooler are respectively connected with the refining tower through a liquid return pipeline;

the liquid return pipeline is provided with a reflux discharging pump, and the reflux discharging pump is provided with two liquid outlets, one is a reflux outlet connected with the refining tower, and the other is a discharge outlet connected to the DMAC storage tank.

2. An improved DMAC recovery system according to claim 1, wherein: the DMAC collection tank is two or more connected in parallel.

3. An improved DMAC recovery system according to claim 2, wherein: valves are arranged on the branch pipelines connected in parallel, and a main pipeline connected with the DMAC collecting tank and the refining tower is provided with a main valve.

4. An improved DMAC recovery system according to claim 1, wherein: and an air outlet of the refrigerator is connected with an exhaust emission system through a water ring vacuum pump.