WO2017190299A1 - Seven-tower five-effect rectification system for dmac or dmf waste liquid and method for recovering same - Google Patents

Abstract

A method for recovering a DMAC or DMF waste liquid using seven-tower five-effect rectification. The waste liquid comprising DMAC or DMF is entered into a DMAC or DMF finished product tank after being successively processed via a preheater, a first concentrating tower, a second concentrating tower, a third concentrating tower, a fourth concentrating tower, a flash drum, a fifth concentrating tower, a rectifying tower and a deacidification tower in the method. The method resolves the problem of solid waste pollution and realizes the recycling of high boilers and solid matter. DMAC and DMF are not decomposed substantially, and the recovering rate of a DMAC or DMF finished product is more than 99%. A seven-tower five-effect rectification system for the DMAC or DMF waste liquid to implement the recovering method is also disclosed.

Description

[Name of invention by ISA according to Rule 37.2] Seven-seven-effect rectification system of DMAC or DMF waste liquid and recovery method thereof Technical field

The invention relates to a solvent recovery method, in particular to a seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, belonging to the field of separation and purification of DMAC (DMF).

Background technique

DMAC, also known as N,N-dimethylacetamide, DMF, also known as N,N-dimethylformamide, is an excellent organic solvent widely used in the pharmaceutical, pesticide, film, leather, textile and other industries. , DMAC (DMF) waste liquid is produced at the same time as the use. Since DMAC (DMF) is a bacteriostatic agent, it also kills activated sludge in the sewage treatment tank at low concentrations. Therefore, there is currently no good way to treat DMAC (DMF) waste liquid by biochemical treatment. In addition, economically, the use of rectification to treat DMAC (DMF) waste liquid is the best choice. At present, there are many rectification methods for DMAC (DMF) waste liquid in China, but there is a common environmental problem: DMAC (DMF) The pyrolysis product, dimethylamine, is toxic and has a foul odor. In recent years, various methods have been adopted to effectively solve the problem of dimethylamine pollution. With the establishment of environmental protection law, the problem of dimethylamine has increasingly attracted the attention of environmental protection bureaus and enterprises. It is urgent to have a good method to fundamentally Solve the problem of dimethylamine.

The Chinese patent No. CN200910228354 discloses a four-effect rectification system and a recovery method for a wet synthetic leather dimethylformamide solution, which has a great improvement in energy saving effect, but since the rectification column adopts atmospheric pressure Distillation, DMF decomposes in a large amount at high temperature, and its decomposition products are formic acid and dimethylamine, and the content of dimethylamine in the top water is about 2000 ppm. At present, the solution of dimethylamine in the top water is to remove dimethylamine from the top water by steam stripping. The dimethylamine in the top water can be removed to below 30 ppm, but two pollutants are regenerated: An aqueous solution having an amine content of about 10% and a dimethylamine gas. These two pollutants are currently sent to the boiler room for incineration. The final products are nitrogen monoxide and nitrogen dioxide, which pollute the environment again, bringing new environmental problems to the enterprise. In addition, due to environmental reasons, many enterprises' own coal-fired boilers are now required to be converted into natural gas boilers or converted to steam in the park in the past two years. The dimethylamine cannot be incinerated. How to deal with dimethylamine has become an urgent problem to be solved recently. Environmental problems.

Summary of the invention

The object of the present invention is to solve the environmental protection problem of the prior art and save energy, and provide a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid with high environmental protection and low energy consumption.

In order to achieve the above object, the present invention provides a seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, and the processing steps of DMAC (DMF) in the material are as follows:

Step 1: The waste liquid containing DMAC (DMF) is pumped into the feed preheater by the waste liquid, and the steam is steamed by the steam condensed water to be preheated and then enters the first concentration tower;

Step 2: After the waste liquid is preheated, it is sent to the first concentration tower (T101) for the first dehydration concentration. The top temperature of the first concentration tower is 40-45 ° C (40 ° C in winter and 45 ° C in summer), and the corresponding tower temperature is 43. -48 ° C;

Step 3: The tower liquid after dehydration and concentration through the first concentration tower is sent to the second concentration tower (T102) by the T101 discharge pump for the second dehydration concentration, and the temperature of the second concentration tower is 53 ° C - 58 ° C, corresponding to The temperature of the tower is 55 ° C -60 ° C;

Step 4: The tower liquid after dehydration and concentration through the second concentration tower is sent to the third concentration tower (T103) by the T102 discharge pump for the third dehydration concentration, and the temperature of the third concentration tower is 65 ° C - 70 ° C, corresponding to Tower temperature of 67 ° C -72 ° C;

Step 5: The tower liquid after dehydration and concentration through the third concentration tower is sent to the fourth concentration tower (T104) by the T103 discharge pump for the fourth dehydration concentration, and the temperature of the fourth concentration tower is 77 ° C-82 ° C, corresponding to Tower temperature of 79 ° C -84 ° C;

Step 6: The tower liquid after dehydration and concentration through the fourth concentration tower is sent to the flash tank by the T104 discharge pump, and then sent to the feed evaporator by the forced circulation pump, and exchanges with the primary steam to enter the flash tank. The internal pressure is flashed to separate the gas and the liquid, and the gas phase is defoamed through the wire mesh demister to enter the fifth concentration column;

Step 7: the gas entering the fifth concentration column in the gas phase is subjected to a fifth dehydration concentration in the fifth concentration column, the temperature of the top of the fifth concentration column is 89 ° C - 94 ° C, and the corresponding column temperature is 91 ° C - 96 ° C;

Step 8: The bottom tank liquid after dehydration and concentration through the fifth concentration column (DMAC (DMF) is pumped by T105 to the middle of the rectification column (T106), and the volatile components in the liquid phase in the rectification column The water is transferred to the gas phase, and the hard-to-volatile component DMAC (DMF) in the gas phase is transferred to the liquid phase. The gas and liquid phases are countercurrently contacted in the column, and the partial gasification and partial condensation are repeated several times to separate the mixed solution. The top of the tower is obtained with pure water containing DMAC (DMF) <150ppm, the pure DMAC (DMF) water is <150ppm in the tower, the top of the distillation column is 40-45°C (winter 40°C, summer 45°C), the corresponding tower temperature 95-100 ° C;

Step 9: When the distillation column bottom liquid contains <150ppm, the T106 discharge pump is sent to the deacidification tower (T107), in the deacidification tower, DMAC (DMF), dimethylamine and water are easily gasified in deacidification. The top of the tower is taken out, condensed by DMAC (DMF) condenser and then entered into DMAC (DMF) reflux tank, and then sent back to the deacidification tower by DMAC (DMF) reflux pump. The hard-to-volatile components DMAC (DMF) and acetic acid (formic acid) The azeotrope remains in the deacidification tower and decomposes by itself, the top of the deacidification tower is 90-95 ° C, and the corresponding tower temperature is 100-105 ° C;

Step 10: Returning the DMAC of the deacidification tower (DMF) to remove the dimethylamine and water, the liquid phase is taken from the upper part of the deacidification tower, cooled by the DMAC (DMF) finished cooler, and then enters the DMAC (DMF) finished tank, and then The finished product tank of the tank area is pumped by DMAC (DMF) finished product.

Optimized, the present invention also provides a seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, and the water treatment steps in the material are as follows:

Step 1: The water vapor from the top of the first concentration tower enters the top condenser and exchanges heat with the circulating water to form the liquid top water into the liquid tank of the first concentration tower, and a part of the water is sent back to the first concentration tower by the T101 reflux pump. T101 pump is sent to the second concentration Tata top liquid tank;

Step 2: The second concentration tower top water vapor enters the first concentration tower reboiler and the first concentration tower bottom liquid heat exchanges into liquid liquid top water, and then enters the second concentration tower top liquid tank, and part of the T102 reflux pump Returning to the second concentration tower, and sending a part of the water from the T102 to the top tank of the third concentration tower;

Step 3: The third concentration tower top water vapor enters the second concentration tower reboiler and the second concentration tower bottom liquid heat exchange into liquid liquid top water, and then enters the third concentration tower top liquid tank, and part of the T103 reflux pump Returning to the third concentration tower, and sending a part of the water from the T103 to the liquid tank of the fourth concentration tower;

Step 4: The fourth concentration tower top water vapor enters the third concentration tower reboiler and the third concentration tower bottom liquid is exchanged into liquid liquid top water, and then enters the fourth concentration tower overhead liquid tank, and part of the T104 reflux pump Returning to the fourth concentration tower, a part of which is sent by the T104 pump to the top tank of the fifth concentration tower;

Step 5: The fifth concentration tower top water vapor enters the fourth concentration tower reboiler and the fourth concentration tower bottom liquid is exchanged into liquid liquid top water, and then enters the fifth concentration tower top liquid tank, and part of the T105 reflux pump Returning to the fifth concentration tower, a part of the water tank sent to the tank area by the T105 pump is returned to the production line for reuse;

Step 6: The steam at the top of the distillation column enters the top of the distillation column and exchanges heat with the circulating water to form a liquid top water into the top liquid tank of the distillation column, and a part of the liquid is sent back to the distillation column by a T106 reflux pump. The T106 water pump is sent to the gas water separation tank and then sent to the fifth concentration tower top liquid tank.

Optimized, the present invention also provides a seven-column five-effect rectification system for DMAC (DMF) waste liquid and a recovery method, and the steps of processing high-boiling substances and solid materials in the material are as follows:

Step 1: Adjust the discharge flow rate by using the discharge regulating valve of the flash tank, and continuously extract the mixed liquid containing high boiler, solid matter, DMAC (DMF) and water in the flash tank into the evaporation kettle, and then flash. The high boilers and solids in the tank maintain a balanced low concentration to reduce clogging of the heat exchange tubes in the feed evaporator.

Step 2: A mixed liquid containing a high boiler, a solid, DMAC (DMF) and water is heated in a vaporizer using a single steam while a high vacuum is used to vaporize the water into the first concentration column at a low temperature.

Step 3: After the water is vaporized, a mixed liquid containing high boilers, solid matter, and DMAC (DMF) is obtained in the evaporation kettle, and is discharged to the production workshop for recycling by using an evaporating kettle discharge pump.

Optimized, the present invention also provides a seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, characterized in that the energy utilization processing steps are as follows:

Step 1: The fifth concentration column reboiler, the feed evaporator, the rectification column reboiler and the deacidification column reboiler energy are one steam heating, and the steam flow is regulated by the respective steam regulating valves to control the four devices. Their respective temperatures;

Step 2: The fifth concentration tower reboiler adopts a steam heating tower liquid, and the water in the tower liquid increases and heats up to form The top water vapor of the fifth concentration tower;

Step 3: The feed evaporator uses one steam to heat the liquid in the flash tank, vaporizes DMAC (DMF) and water into the fifth concentration tower, and the water vapor rises to form the top water vapor of the fifth concentration tower;

Step 4: The top water vapor of the fifth concentration tower is heated to the fourth concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and vaporized to form the water vapor at the top of the fourth concentration tower.

Step 5: The top water vapor of the fourth concentration tower is heated to the third concentration column reboiler, and the water in the bottom liquid of the tower is heated and vaporized to form the top water vapor of the third concentration tower.

Step 6: The top water vapor of the third concentration tower heats the second concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and vaporized to form the water vapor at the top of the second concentration tower.

Step 7: The top water vapor of the second concentration tower heats the first concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and vaporized to form the top water vapor of the first concentration tower.

Step 8: The water vapor at the top of the first concentration tower is exchanged with the circulating water to form liquid top water into the liquid tank of the first concentration tower.

Step 9: The rectification column reboiler adopts a steam heating tower liquid, and the water in the tower is heated and vaporized by energy transfer to form the top water vapor of the rectification tower;

Step 10: The water vapor at the top of the rectification column is exchanged with the circulating water to form a liquid top water into the liquid tank of the distillation column.

Step 11: The deacidification tower reboiler adopts a steam heating tower liquid, and the DMAC (DMF) heat exchange gasification in the tower is increased by energy transfer to form the top DMAC (DMF) vapor of the deacidification tower;

Step 12: The overhead DMAC (DMF) vapor of the deacidification column is exchanged with the circulating water to form a liquid DMAC (DMF) into a DMAC (DMF) reflux tank.

Optimized, the present invention also provides a seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, characterized in that the processing steps of vacuum utilization are as follows:

Step 1: The first concentration tower, the second concentration tower, the third concentration tower, the fourth concentration tower, the fifth concentration tower, the rectification tower and the deacidification tower are all vacuum operated, and the intake air flow is regulated by respective vacuum regulating valves. To control the respective vacuum of the seven towers;

Step 2: The first concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.09MPa-0.0925MPa

Step 3: The second concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.0815MPa-0.0855MPa

Step 4: The third concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.066 MPa - 0.072 MPa.

Step 5: The fourth concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.048 MPa - 0.057 MPa.

Step 6: The fifth concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.018 MPa - 0.032 MPa.

Step 7: The distillation column is pumped by a water ring vacuum pump, and the vacuum degree at the top of the column is: -0.09MPa-0.0925MPa

Step 8: The deacidification tower is pumped by a vacuum pump of a rectification tower, and the vacuum degree at the top of the tower is: -0.086 MPa - 0.09 MPa.

Optimized, the present invention also provides a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid, comprising: a feed preheater, a first concentration tower, and a second concentration tower , third concentration tower, fourth concentration tower, fifth concentration tower, rectification tower, deacidification tower, flash tank, feed evaporator, DMAC (DMF) finished cooler, DMAC (DMF) condenser, DMAC ( DMF) reflux tank, DMAC (DMF) finished tank;

The material outlet of the waste liquid tank in the tank area is connected to the feed inlet of the feed preheater through the waste liquid pump, and the material exit of the feed preheater is connected with the material inlet of the first concentration tower, and the material outlet of the first concentration tower is discharged through T101. The pump is connected to the material inlet of the second concentration tower, and the material outlet of the second concentration tower is connected to the material inlet of the third concentration tower via the T102 discharge pump, and the material outlet of the third concentration tower is passed through the T103 discharge pump and the fourth concentration tower. The material inlet is connected, and the material outlet of the fourth concentration tower is connected to the liquid material inlet of the flash tank through the T104 discharge pump, and the liquid material outlet of the flash tank is connected to the material inlet of the feed evaporator through the forced circulation pump. The material outlet of the feed evaporator is connected to the gas phase material inlet of the flash tank, the gas phase material outlet of the flash tank is connected with the material inlet of the fifth concentration tower, and the material outlet of the fifth concentration tower is passed through the T105 discharge pump and the distillation tower. The material inlet is connected, and the material outlet of the rectification tower is connected to the material inlet of the deacidification tower through the T106 discharge pump, and the gas phase material outlet of the deacidification tower is connected with the material inlet of the DMAC (DMF) condenser, DMAC (DMF) Condenser The outlet is connected to the material inlet of the DMAC (DMF) reflux tank, and the material outlet of the DMAC (DMF) reflux tank is connected to the reflux port of the top of the deacidification tower via a DMAC (DMF) reflux pump. The liquid phase material outlet of the deacidification tower and the DMAC The material inlet of the (DMF) finished cooler is connected, the material outlet of the DMAC (DMF) finished cooler is connected with the material inlet of the DMAC (DMF) finished tank, and the material export of the DMAC (DMF) finished tank is processed by the DMAC (DMF) finished pump and The material inlets of the finished tanks in the tank area are connected.

Optimized, the present invention also provides a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid, comprising: an overhead condenser, a first concentration tower reboiler, and a second Concentration tower reboiler, third concentration tower reboiler, fourth concentration tower reboiler, distillation tower overhead condenser, first concentration tower overhead liquid tank, second concentration tower overhead liquid tank, third Concentration tower overhead liquid tank, fourth concentration tower overhead liquid tank, fifth concentration tower overhead liquid tank, and distillation tower top liquid tank;

The overhead vapor outlet of the first concentration tower is connected to the steam inlet of the overhead condenser, and the condensate outlet of the overhead condenser is connected to the condensate inlet of the first concentration tank overhead tank, the first concentration tower overhead tank The water outlet is connected to the top reflux port of the first concentration tower via a T101 reflux pump, and the water outlet of the first concentration tower overhead liquid tank is connected to the water inlet of the second concentration tower overhead liquid tank via the T101 outlet water pump. The overhead vapor outlet of the second concentration column is connected to the steam inlet of the first concentration column reboiler, and the condensate outlet of the first concentration column reboiler is connected to the condensate inlet of the second concentration column overhead tank, second The outlet of the top tank of the concentration tower is connected to the reflux port of the second concentration tower via a T102 reflux pump, and the outlet of the liquid tank of the second concentration tower is passed through the T102 outlet water pump and the third concentration tower top liquid tank. The water inlet is connected. The top steam outlet of the third concentration tower and the second thick The steam inlet of the condensation tower reboiler is connected, the condensate outlet of the second concentration tower reboiler is connected with the condensate inlet of the third concentration tower overhead tank, and the outlet of the third concentration tower overhead tank is refluxed by T103. The pump is connected to the top return port of the third concentration column, and the water outlet of the third concentration column top liquid tank is connected to the water inlet of the fourth concentration column top liquid tank via the T103 output pump. The overhead vapor outlet of the fourth concentration column is connected to the steam inlet of the third concentration column reboiler, and the condensate outlet of the third concentration column reboiler is connected to the condensate inlet of the fourth concentration tower overhead liquid tank, fourth The outlet of the top tank of the concentration tower is connected to the reflux port of the fourth concentration tower via a T104 reflux pump, and the outlet of the liquid tank of the fourth concentration tower is passed through the T104 outlet pump and the fifth concentration tower overhead tank. The water inlet is connected. The overhead vapor outlet of the fifth concentration column is connected to the steam inlet of the fourth concentration column reboiler, and the condensate outlet of the fourth concentration column reboiler is connected to the condensate inlet of the fifth concentration column overhead liquid tank, fifth The outlet of the top tank of the concentration tower is connected to the reflux port of the top of the fifth concentration tower via a T105 reflux pump, and the outlet of the liquid tank of the fifth concentration tower is fed through the T105 water pump and the top tank of the tank area. The nozzles are connected. The overhead steam outlet of the rectification column is connected to the steam inlet of the top condenser of the rectification column, and the condensate outlet of the top condenser of the rectification column is connected to the condensate inlet of the top tank of the rectification column, and the distillation tower is connected The water outlet of the top liquid tank is connected to the top reflux port of the rectification column through a T106 reflux pump, and the water outlet of the top liquid tank of the rectification tower is connected to the water inlet of the gas water separation tank through the T106 outlet pump. The water outlet of the gas water separation tank is connected to the water inlet of the liquid tank of the fifth concentration tower through the gas water separation tank outlet water pump.

Optimized, the present invention also provides a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid, comprising: a flash tank, an evaporation kettle and a first concentration tower;

The slag outlet of the flash tank is connected to the feed port of the evaporation kettle, and the gas phase discharge port of the evaporation kettle is connected to the gas phase feed port of the first concentration column, and the liquid phase discharge port of the evaporation kettle is discharged through the evaporation vessel discharge pump and The feed port of the ingredient storage tank in the production workshop is connected. The primary steam is connected to the steam inlet of the evaporator, and the condensate outlet of the evaporator is connected to the condensate inlet of the hot water tank.

Optimized, the present invention also provides a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid, comprising: a fifth concentration column reboiler, a feed evaporator, and a rectification Tower reboiler, deacidification column reboiler, fourth concentration tower reboiler, third concentration tower reboiler, second concentration tower reboiler, first concentration tower reboiler, first concentration tower top Liquid tank, distillation tower overhead tank, DMAC (DMF) reflux tank;

The primary steam is connected to the vapor inlet of the fifth concentration column reboiler, the feed evaporator, the rectification column reboiler and the deacidification column reboiler, and the condensate outlets of the four plants are connected to the condensate inlet of the hot water tank. The overhead steam outlet of the fifth concentration tower is connected to the steam inlet of the fourth concentration tower reboiler, and the overhead steam outlet of the fourth concentration tower is connected to the steam inlet of the third concentration tower reboiler, and the tower of the third concentration tower The top steam outlet is connected to the steam inlet of the second concentration column reboiler, and the overhead steam outlet of the second concentration column is connected to the steam inlet of the first concentration column reboiler, and the top vapor outlet and the top of the first concentration tower The steam inlet of the condenser is connected, and the condensate outlet of the overhead condenser is connected to the condensate inlet of the tank of the first concentration column. The overhead steam outlet of the rectification column is connected to the steam inlet of the top condenser of the rectification column, and the condensate outlet of the top condenser of the rectification column is The condensate inlet of the liquid tank of the distillation column is connected. The overhead DMAC (DMF) vapor outlet of the deacidification column is connected to the steam inlet of the DMAC (DMF) condenser, and the finished product outlet of the DMAC (DMF) condenser is connected to the finished product inlet of the DMAC (DMF) reflux tank.

The invention further provides an apparatus for recovering a seven-column five-effect rectification system of DMAC (DMF) waste liquid and a method for recovering the same, comprising: a first concentration tower, a second concentration tower, a third concentration tower, a water circulation vacuum pump of a fourth concentration tower, a fifth concentration tower, and a rectification tower;

The vacuum ports of the first concentration tower, the second concentration tower, the third concentration tower, the fourth concentration tower, the fifth concentration tower, and the rectification tower are connected to the inlets of the respective water ring vacuum pumps, and the gas outlets of the water ring vacuum pumps are The air inlet of the gas water separation tank is connected.

The invention has the advantage of solving the problems of air pollution and water pollution. The decomposition reaction of DMAC (DMF) is an autocatalytic reaction. In the presence of an acid or a base, it accelerates its decomposition, and it decomposes slightly under 120 °C. The decomposition amount increases with the increase of temperature above 120 °C. . Therefore, only low temperature concentration and cryogenic rectification and low temperature deacidification can fundamentally inhibit the decomposition of DMAC (DMF). The DMAC (DMF) of the invention is concentrated within 100 ° C, and is subjected to rectification and deacidification within 105 ° C. The whole process is carried out at a low temperature, DMAC (DMF) is basically not decomposed, and finally the product of DMAC (DMF) decomposition is two. Methylamine in the atmosphere <10mg / m ³ , can be discharged to the standard; in the top of the water content <30ppm, can be reused back to the production line. Thoroughly solved air pollution and water pollution.

Compared with the prior art, the beneficial effects provided by the present invention are embodied in:

1. The invention has the advantages of solving the problem of solid waste pollution, realizing the recycling of high boilers and solid materials, and turning pollution into treasure. The high boilers and solids in the DMAC (DMF) waste liquid are the raw materials in the production process. After the high-vacuum low temperature is used to remove the water in the evaporation kettle, a mixture containing high boilers, solid matter and DMAC (DMF) is formed. Liquid can be returned to the production line for reuse.

2. The advantage of the invention is that it is more energy-saving. Since the heat is utilized five times in the DMAC (DMF) waste liquid concentration process, it is used more than the prior art, and the energy saving effect is obvious, and the energy saving is compared with the four-effect distillation system. %.

3. The invention has the advantages of high recovery rate and good product quality. Since DMAC (DMF) is concentrated within 100 ° C, rectification and deacidification are carried out within 105 ° C, DMAC (DMF) does not substantially decompose, DMAC (DMF) The recovery rate of the finished product is >99%, while the DMAC (DMF) finished product has a water content of <200 ppm, acetic acid <20 ppm, and dimethylamine <10 ppm.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a process flow diagram of the present invention.

detailed description

The embodiments of the present invention are described in detail below. The present embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation procedures are given, but the scope of protection of the present invention is not limited to the following implementation. example.

The invention solves the prior art air pollution and water pollution, and provides a technical solution: DMAC (DMF) is concentrated within 100 ° C, rectification and deacidification are carried out within 105 ° C, and the whole process is carried out at a low temperature, DMAC (DMF) basically does not decompose, including the following steps:

Step 1: The waste liquid containing DMAC (DMF) is pumped into the feed preheater by the waste liquid, and the steam is steamed by the steam condensed water to be preheated and then enters the first concentration tower;

Step 2: After the waste liquid is preheated, it is sent to the first concentration tower (T101) for the first dehydration concentration. The top temperature of the first concentration tower is 40-45 ° C (40 ° C in winter and 45 ° C in summer), and the corresponding tower temperature is 43. -48 ° C;

Step 3: The tower liquid after dehydration and concentration through the first concentration tower is sent to the second concentration tower (T102) by the T101 discharge pump for the second dehydration concentration, and the temperature of the second concentration tower is 53 ° C - 58 ° C, corresponding to The temperature of the tower is 55 ° C -60 ° C;

Step 4: The tower liquid after dehydration and concentration through the second concentration tower is sent to the third concentration tower (T103) by the T102 discharge pump for the third dehydration concentration, and the temperature of the third concentration tower is 65 ° C - 70 ° C, corresponding to Tower temperature of 67 ° C -72 ° C;

Step 5: The tower liquid after dehydration and concentration through the third concentration tower is sent to the fourth concentration tower (T104) by the T103 discharge pump for the fourth dehydration concentration, and the temperature of the fourth concentration tower is 77 ° C-82 ° C, corresponding to Tower temperature of 79 ° C -84 ° C;

Step 6: The tower liquid after dehydration and concentration through the fourth concentration tower is sent to the flash tank by the T104 discharge pump, and then sent to the feed evaporator by the forced circulation pump, and exchanges with the primary steam to enter the flash tank. The internal pressure is flashed to separate the gas and the liquid, and the gas phase is defoamed through the wire mesh demister to enter the fifth concentration column;

Step 7: the gas entering the fifth concentration column in the gas phase is subjected to a fifth dehydration concentration in the fifth concentration column, the temperature of the top of the fifth concentration column is 89 ° C - 94 ° C, and the corresponding column temperature is 91 ° C - 96 ° C;

Step 8: The bottom tank liquid after dehydration and concentration through the fifth concentration column (DMAC (DMF) is pumped by T105 to the middle of the rectification column (T106), and the volatile components in the liquid phase in the rectification column The water is transferred to the gas phase, and the hard-to-volatile component DMAC (DMF) in the gas phase is transferred to the liquid phase. The gas and liquid phases are countercurrently contacted in the column, and the partial gasification and partial condensation are repeated several times to separate the mixed solution. The top of the tower is obtained with pure water containing DMAC (DMF) <150ppm, the pure DMAC (DMF) water is <150ppm in the tower, the top of the distillation column is 40-45°C (winter 40°C, summer 45°C), the corresponding tower temperature 95-100 ° C;

Step 9: When the distillation column bottom liquid contains <150ppm, the T106 discharge pump is sent to the deacidification tower (T107), DMAC (DMF) and ppm grade dimethylamine, ppm level water in the deacidification tower. Easy gasification is produced at the top of the deacidification tower, condensed by DMAC (DMF) condenser and then into DMAC (DMF) reflux tank, and then sent back to the deacidification tower by DMAC (DMF) reflux pump. DMAC (DMF) The azeotrope with acetic acid (formic acid) is left in the deacidification tower to decompose and balance itself, the top of the deacidification tower is 90-95 ° C, and the corresponding tower temperature is 100-105 ° C;

Step 10: Returning the DMAC of the deacidification tower (DMF) to remove the dimethylamine and water, the liquid phase is taken from the upper part of the deacidification tower, cooled by the DMAC (DMF) finished cooler, and then enters the DMAC (DMF) finished tank, and then Pumped into the tank with DMAC (DMF) finished product Finished cans in the district.

The invention solves the solid waste pollution of the prior art, and adopts the technical scheme: the high-boiling and solid matter in the material is reused in the production workshop after high-vacuum low-temperature dehydration, and the following steps are included:

Step 1: Adjust the discharge flow rate by using the discharge regulating valve of the flash tank, and continuously extract the mixed liquid containing high boiler, solid matter, DMAC (DMF) and water in the flash tank into the evaporation kettle, and then flash. The high boilers and solids in the tank maintain a balanced low concentration to reduce clogging of the heat exchange tubes in the feed evaporator.

Step 2: A mixed liquid containing a high boiler, a solid, DMAC (DMF) and water is heated in a vaporizer using a single steam while a high vacuum is used to vaporize the water into the first concentration column at a low temperature.

Step 3: After the water is vaporized, a mixed liquid containing high boilers, solid matter, and DMAC (DMF) is obtained in the evaporation kettle, and is discharged to the production workshop for recycling by using an evaporating kettle discharge pump.

The invention is more energy-saving than the prior art, and the technical solution adopted is: the heat is utilized five times in the concentration process, and the utility model is used once more than the prior art, and the energy-saving effect is obvious, and the method comprises the following steps:

Step 1: The fifth concentration tower reboiler adopts a steam heating tower liquid, and the water in the tower liquid is vaporized and rises to form the top water vapor of the fifth concentration tower;

Step 2: The feed evaporator uses a steam to heat the liquid in the flash tank, vaporizes DMAC (DMF) and water into the fifth concentration tower, and the water vapor rises to form the top water vapor of the fifth concentration tower;

Step 3: The top water vapor of the fifth concentration tower is heated to the fourth concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and heated to form the top water vapor of the fourth concentration tower.

Step 4: The top water vapor of the fourth concentration tower is heated to the third concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and heated to form the top water vapor of the third concentration tower.

Step 5: The top water vapor of the third concentration tower heats the second concentration column reboiler, and the water in the bottom liquid of the tower is heated and vaporized to form the top water vapor of the second concentration tower.

Step 6: The top water vapor of the second concentration tower heats the first concentration column reboiler, and the water in the bottom liquid of the tower is heated and vaporized to form the top water vapor of the first concentration tower.

Step 7: The water vapor at the top of the first concentration tower is exchanged with the circulating water to form liquid top water into the liquid tank of the first concentration tower.

Table 1 compares the four-effect rectification system with the present invention in terms of utility conditions and operating conditions.

Table 1

The invention has the advantage of solving the problems of air pollution and water pollution. The decomposition reaction of DMAC (DMF) is an autocatalytic reaction. In the presence of an acid or a base, it accelerates its decomposition, and it decomposes slightly under 120 °C. The decomposition amount increases with the increase of temperature above 120 °C. . Therefore, only low temperature concentration and cryogenic rectification and low temperature deacidification can fundamentally inhibit the decomposition of DMAC (DMF). The DMAC (DMF) of the invention is concentrated within 100 ° C, and is subjected to rectification and deacidification within 105 ° C. The whole process is carried out at a low temperature, DMAC (DMF) is basically not decomposed, and finally the product of DMAC (DMF) decomposition is two. Methylamine in the atmosphere <10mg / m ³ , can be discharged to the standard; in the top of the water content <30ppm, can be reused back to the production line. Thoroughly solved air pollution and water pollution.

The invention has the advantages of solving the problem of solid waste pollution, realizing the recycling of high boilers and solid materials, and turning pollution into treasure. The high boilers and solids in the DMAC (DMF) waste liquid are the raw materials in the production process. After the high-vacuum low temperature is used to remove the water in the evaporation kettle, a mixture containing high boilers, solid matter and DMAC (DMF) is formed. Liquid can be returned to the production line for reuse.

The invention has the advantages that it is more energy-saving. Since the heat is utilized five times in the DMAC (DMF) waste liquid concentration process, it is used more than the prior art, and the energy saving effect is obvious, and the energy saving is 16% compared with the four-effect distillation system.

The invention has the advantages of high recovery rate and good product quality, and since DMAC (DMF) is concentrated within 100 ° C, Distillation and deacidification within 105 ° C, DMAC (DMF) is basically not decomposed, DMAC (DMF) finished product recovery rate > 99%, while DMAC (DMF) finished product water <200ppm, acetic acid <20ppm, dimethylamine <10ppm .

According to the above data, the present invention not only solves environmental protection problems but also creates good economic benefits.

In addition, it should be understood that although the description is described in terms of embodiments, not every embodiment includes only one independent technical solution. The description of the specification is merely for the sake of clarity, and those skilled in the art should regard the specification as a whole. The technical solutions in the respective embodiments may also be combined as appropriate to form other embodiments that can be understood by those skilled in the art.

Claims (10)

1. A seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, characterized in that the processing steps of DMAC (DMF) in the material are as follows:

   Step 1: The waste liquid containing DMAC (DMF) is pumped into the feed preheater by the waste liquid, and the steam is steamed by the steam condensed water to be preheated and then enters the first concentration tower;

   Step 2: After the waste liquid is preheated, it is sent to the first concentration tower (T101) for the first dehydration concentration. The top temperature of the first concentration tower is 40-45 ° C (40 ° C in winter and 45 ° C in summer), and the corresponding tower temperature is 43. -48 ° C;

   Step 3: The tower liquid after dehydration and concentration through the first concentration tower is sent to the second concentration tower (T102) by the T101 discharge pump for the second dehydration concentration, and the temperature of the second concentration tower is 53 ° C - 58 ° C, corresponding to The temperature of the tower is 55 ° C -60 ° C;

   Step 4: The tower liquid after dehydration and concentration through the second concentration tower is sent to the third concentration tower (T103) by the T102 discharge pump for the third dehydration concentration, and the temperature of the third concentration tower is 65 ° C - 70 ° C, corresponding to Tower temperature of 67 ° C -72 ° C;

   Step 5: The tower liquid after dehydration and concentration through the third concentration tower is sent to the fourth concentration tower (T104) by the T103 discharge pump for the fourth dehydration concentration, and the temperature of the fourth concentration tower is 77 ° C-82 ° C, corresponding to Tower temperature of 79 ° C -84 ° C;

   Step 6: The tower liquid after dehydration and concentration through the fourth concentration tower is sent to the flash tank by the T104 discharge pump, and then sent to the feed evaporator by the forced circulation pump, and exchanges with the primary steam to enter the flash tank. The internal pressure is flashed to separate the gas and the liquid, and the gas phase is defoamed through the wire mesh demister to enter the fifth concentration column;

   Step 7: the gas entering the fifth concentration column in the gas phase is subjected to a fifth dehydration concentration in the fifth concentration column, the temperature of the top of the fifth concentration column is 89 ° C - 94 ° C, and the corresponding column temperature is 91 ° C - 96 ° C;

   Step 8: The bottom tank liquid after dehydration and concentration through the fifth concentration column (DMAC (DMF) is pumped by T105 to the middle of the rectification column (T106), and the volatile components in the liquid phase in the rectification column The water is transferred to the gas phase, and the hard-to-volatile component DMAC (DMF) in the gas phase is transferred to the liquid phase. The gas and liquid phases are countercurrently contacted in the column, and the partial gasification and partial condensation are repeated several times to separate the mixed solution. The top of the tower is obtained with pure water containing DMAC (DMF) <150ppm, the pure DMAC (DMF) water is <150ppm in the tower, the top of the distillation column is 40-45°C (winter 40°C, summer 45°C), the corresponding tower temperature 95-100 ° C;

   Step 9: When the distillation column bottom liquid contains <150ppm, the T106 discharge pump is sent to the deacidification tower (T107), in the deacidification tower, DMAC (DMF), dimethylamine and water are easily gasified in deacidification. The top of the tower is taken out, condensed by DMAC (DMF) condenser and then entered into DMAC (DMF) reflux tank, and then sent back to the deacidification tower by DMAC (DMF) reflux pump. The hard-to-volatile components DMAC (DMF) and acetic acid (formic acid) The azeotrope remains in the deacidification tower and decomposes by itself, the top of the deacidification tower is 90-95 ° C, and the corresponding tower temperature is 100-105 ° C;

   Step 10: Returning the DMAC of the deacidification tower (DMF) to remove the dimethylamine and water, the liquid phase is taken from the upper part of the deacidification tower, cooled by the DMAC (DMF) finished cooler, and then enters the DMAC (DMF) finished tank, and then The finished product tank of the tank area is pumped by DMAC (DMF) finished product.
2. A seven-tower five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, characterized in that the water treatment steps in the material are as follows:

   Step 1: The water vapor from the top of the first concentration tower enters the top condenser and exchanges heat with the circulating water to form the liquid top water into the liquid tank of the first concentration tower, and a part of the water is sent back to the first concentration tower by the T101 reflux pump. The T101 outlet pump is sent to the second concentration tower top liquid tank;

   Step 2: The second concentration tower top water vapor enters the first concentration tower reboiler and the first concentration tower bottom liquid heat exchanges into liquid liquid top water, and then enters the second concentration tower top liquid tank, and part of the T102 reflux pump Returning to the second concentration tower, and sending a part of the water from the T102 to the top tank of the third concentration tower;

   Step 3: The third concentration tower top water vapor enters the second concentration tower reboiler and the second concentration tower bottom liquid heat exchange into liquid liquid top water, and then enters the third concentration tower top liquid tank, and part of the T103 reflux pump Returning to the third concentration tower, and sending a part of the water from the T103 to the liquid tank of the fourth concentration tower;

   Step 4: The fourth concentration tower top water vapor enters the third concentration tower reboiler and the third concentration tower bottom liquid is exchanged into liquid liquid top water, and then enters the fourth concentration tower overhead liquid tank, and part of the T104 reflux pump Returning to the fourth concentration tower, a part of which is sent by the T104 pump to the top tank of the fifth concentration tower;

   Step 5: The fifth concentration tower top water vapor enters the fourth concentration tower reboiler and the fourth concentration tower bottom liquid is exchanged into liquid liquid top water, and then enters the fifth concentration tower top liquid tank, and part of the T105 reflux pump Returning to the fifth concentration tower, a part of the water tank sent to the tank area by the T105 pump is returned to the production line for reuse;

   Step 6: The steam at the top of the distillation column enters the top of the distillation column and exchanges heat with the circulating water to form a liquid top water into the top liquid tank of the distillation column, and a part of the liquid is sent back to the distillation column by a T106 reflux pump. The T106 water pump is sent to the gas water separation tank and then sent to the fifth concentration tower top liquid tank.
3. A seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, the processing steps of high-boiling substances and solid substances in the material are as follows:

   Step 1: Adjust the discharge flow rate by using the discharge regulating valve of the flash tank, and continuously extract the mixed liquid containing high boiler, solid matter, DMAC (DMF) and water in the flash tank into the evaporation kettle, and then flash. The high boilers and solids in the tank maintain a balanced low concentration to reduce clogging of the heat exchange tubes in the feed evaporator.

   Step 2: A mixed liquid containing a high boiler, a solid, DMAC (DMF) and water is heated in a vaporizer using a single steam while a high vacuum is used to vaporize the water into the first concentration column at a low temperature.

   Step 3: After the water is vaporized, a mixed liquid containing high boilers, solid matter, and DMAC (DMF) is obtained in the evaporation kettle, and is discharged to the production workshop for recycling by using an evaporating kettle discharge pump.
4. Seven-seven-effect rectification system and recovery method for DMAC (DMF) waste liquid, characterized in that energy utilization The processing steps are as follows:

   Step 1: The fifth concentration column reboiler, the feed evaporator, the rectification column reboiler and the deacidification column reboiler energy are one steam heating, and the steam flow is regulated by the respective steam regulating valves to control the four devices. Their respective temperatures;

   Step 2: The fifth concentration column reboiler adopts a steam heating tower liquid, and the water in the bottom liquid of the tower is vaporized and rises to form the water vapor of the top of the fifth concentration tower;

   Step 3: The feed evaporator uses one steam to heat the liquid in the flash tank, vaporizes DMAC (DMF) and water into the fifth concentration tower, and the water vapor rises to form the top water vapor of the fifth concentration tower;

   Step 4: The top water vapor of the fifth concentration tower is heated to the fourth concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and vaporized to form the water vapor at the top of the fourth concentration tower.

   Step 5: The top water vapor of the fourth concentration tower is heated to the third concentration column reboiler, and the water in the bottom liquid of the tower is heated and vaporized to form the top water vapor of the third concentration tower.

   Step 6: The top water vapor of the third concentration tower heats the second concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and vaporized to form the water vapor at the top of the second concentration tower.

   Step 7: The top water vapor of the second concentration tower heats the first concentration column reboiler, and the water in the bottom liquid of the tower is vaporized and vaporized to form the top water vapor of the first concentration tower.

   Step 8: The water vapor at the top of the first concentration tower is exchanged with the circulating water to form liquid top water into the liquid tank of the first concentration tower.

   Step 9: The rectification column reboiler adopts a steam heating tower liquid, and the water in the tower is heated and vaporized by energy transfer to form the top water vapor of the rectification tower;

   Step 10: The water vapor at the top of the rectification column is exchanged with the circulating water to form a liquid top water into the liquid tank of the distillation column.

   Step 11: The deacidification tower reboiler adopts a steam heating tower liquid, and the DMAC (DMF) heat exchange gasification in the tower is increased by energy transfer to form the top DMAC (DMF) vapor of the deacidification tower;

   Step 12: The overhead DMAC (DMF) vapor of the deacidification column is exchanged with the circulating water to form a liquid DMAC (DMF) into a DMAC (DMF) reflux tank.
5. A seven-column five-effect rectification system and a recovery method for DMAC (DMF) waste liquid, characterized in that the processing steps of vacuum utilization are as follows:

   Step 1: The first concentration tower, the second concentration tower, the third concentration tower, the fourth concentration tower, the fifth concentration tower, the rectification tower and the deacidification tower are all vacuum operated, and the intake air flow is regulated by respective vacuum regulating valves. To control the respective vacuum of the seven towers;

   Step 2: The first concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.09MPa-0.0925MPa

   Step 3: The second concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.0815MPa-0.0855MPa

   Step 4: The third concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.066 MPa - 0.072 MPa.

   Step 5: The fourth concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.048 MPa - 0.057 MPa.

   Step 6: The fifth concentration tower is pumped by a water ring vacuum pump, and the vacuum degree at the top of the tower is: -0.018 MPa - 0.032 MPa.

   Step 7: The distillation column is pumped by a water ring vacuum pump, and the vacuum degree at the top of the column is: -0.09MPa-0.0925MPa

   Step 8: The deacidification tower is pumped by a vacuum pump of a rectification tower, and the vacuum degree at the top of the tower is: -0.086 MPa - 0.09 MPa.
6. The apparatus for recovering a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid according to claim 1, comprising: a feed preheater, a first concentration tower, a second concentration tower, Third concentration tower, fourth concentration tower, fifth concentration tower, rectification tower, deacidification tower, flash tank, feed evaporator, DMAC (DMF) finished cooler, DMAC (DMF) condenser, DMAC (DMF) Recirculation tank, DMAC (DMF) finished product tank;

   The material outlet of the waste liquid tank in the tank area is connected to the feed inlet of the feed preheater through the waste liquid pump, and the material exit of the feed preheater is connected with the material inlet of the first concentration tower, and the material outlet of the first concentration tower is discharged through T101. The pump is connected to the material inlet of the second concentration tower, and the material outlet of the second concentration tower is connected to the material inlet of the third concentration tower via the T102 discharge pump, and the material outlet of the third concentration tower is passed through the T103 discharge pump and the fourth concentration tower. The material inlet is connected, and the material outlet of the fourth concentration tower is connected to the liquid material inlet of the flash tank through the T104 discharge pump, and the liquid material outlet of the flash tank is connected to the material inlet of the feed evaporator through the forced circulation pump. The material outlet of the feed evaporator is connected to the gas phase material inlet of the flash tank, the gas phase material outlet of the flash tank is connected with the material inlet of the fifth concentration tower, and the material outlet of the fifth concentration tower is passed through the T105 discharge pump and the distillation tower. The material inlet is connected, and the material outlet of the rectification tower is connected to the material inlet of the deacidification tower through the T106 discharge pump, and the gas phase material outlet of the deacidification tower is connected with the material inlet of the DMAC (DMF) condenser, DMAC (DMF) Condenser The outlet is connected to the material inlet of the DMAC (DMF) reflux tank, and the material outlet of the DMAC (DMF) reflux tank is connected to the reflux port of the top of the deacidification tower via a DMAC (DMF) reflux pump. The liquid phase material outlet of the deacidification tower and the DMAC The material inlet of the (DMF) finished cooler is connected, the material outlet of the DMAC (DMF) finished cooler is connected with the material inlet of the DMAC (DMF) finished tank, and the material export of the DMAC (DMF) finished tank is processed by the DMAC (DMF) finished pump and The material inlets of the finished tanks in the tank area are connected.
7. The apparatus for recovering a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid according to claim 2, comprising: an overhead condenser, a first concentration tower reboiler, and a second concentration Tower reboiler, third concentration tower reboiler, fourth concentration tower reboiler, distillation tower overhead condenser, first concentration tower overhead tank, second concentration tower overhead tank, third concentration Tata top liquid tank, fourth concentration tower top liquid tank, fifth concentration tower top liquid tank, and distillation tower top liquid tank;

   The overhead vapor outlet of the first concentration tower is connected to the steam inlet of the overhead condenser, and the condensate outlet of the overhead condenser is connected to the condensate inlet of the first concentration tank overhead tank, the first concentration tower overhead tank The water outlet is connected to the top reflux port of the first concentration tower via a T101 reflux pump, and the water outlet of the first concentration tower overhead liquid tank passes through the T101 water pump and the second concentration tower. The water inlet of the top tank is connected. The overhead vapor outlet of the second concentration column is connected to the steam inlet of the first concentration column reboiler, and the condensate outlet of the first concentration column reboiler is connected to the condensate inlet of the second concentration column overhead tank, second The outlet of the top tank of the concentration tower is connected to the reflux port of the second concentration tower via a T102 reflux pump, and the outlet of the liquid tank of the second concentration tower is passed through the T102 outlet water pump and the third concentration tower top liquid tank. The water inlet is connected. The overhead vapor outlet of the third concentration column is connected to the steam inlet of the second concentration column reboiler, and the condensate outlet of the second concentration column reboiler is connected to the condensate inlet of the third concentration column overhead liquid tank, third The outlet of the top tank of the concentration tower is connected to the reflux port of the third concentration tower via a T103 reflux pump, and the outlet of the liquid tank of the third concentration tower is passed through the T103 outlet pump and the fourth concentration tower overhead tank. The water inlet is connected. The overhead vapor outlet of the fourth concentration column is connected to the steam inlet of the third concentration column reboiler, and the condensate outlet of the third concentration column reboiler is connected to the condensate inlet of the fourth concentration tower overhead liquid tank, fourth The outlet of the top tank of the concentration tower is connected to the reflux port of the fourth concentration tower via a T104 reflux pump, and the outlet of the liquid tank of the fourth concentration tower is passed through the T104 outlet pump and the fifth concentration tower overhead tank. The water inlet is connected. The overhead vapor outlet of the fifth concentration column is connected to the steam inlet of the fourth concentration column reboiler, and the condensate outlet of the fourth concentration column reboiler is connected to the condensate inlet of the fifth concentration column overhead liquid tank, fifth The outlet of the top tank of the concentration tower is connected to the reflux port of the top of the fifth concentration tower via a T105 reflux pump, and the outlet of the liquid tank of the fifth concentration tower is fed through the T105 water pump and the top tank of the tank area. The nozzles are connected. The overhead steam outlet of the rectification column is connected to the steam inlet of the top condenser of the rectification column, and the condensate outlet of the top condenser of the rectification column is connected to the condensate inlet of the top tank of the rectification column, and the distillation tower is connected The water outlet of the top liquid tank is connected to the top reflux port of the rectification column through a T106 reflux pump, and the water outlet of the top liquid tank of the rectification tower is connected to the water inlet of the gas water separation tank through the T106 outlet pump. The water outlet of the gas water separation tank is connected to the water inlet of the liquid tank of the fifth concentration tower through the gas water separation tank outlet water pump.
8. The apparatus for recovering a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid according to claim 3, comprising: a flash tank, an evaporation tank and a first concentration tower;

   The slag outlet of the flash tank is connected to the feed port of the evaporation kettle, and the gas phase discharge port of the evaporation kettle is connected to the gas phase feed port of the first concentration column, and the liquid phase discharge port of the evaporation kettle is discharged through the evaporation vessel discharge pump and The feed port of the ingredient storage tank in the production workshop is connected. The primary steam is connected to the steam inlet of the evaporator, and the condensate outlet of the evaporator is connected to the condensate inlet of the hot water tank.
9. The apparatus for recovering a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid according to claim 4, comprising: a fifth concentration column reboiler, a feed evaporator, and a rectification tower Reboiler, deacidification tower reboiler, fourth concentration tower reboiler, third concentration tower reboiler, second concentration tower reboiler, first concentration tower reboiler, first concentration tower overhead liquid Tank, distillation tower overhead tank, DMAC (DMF) reflux tank;

   The primary steam is connected to the vapor inlet of the fifth concentration column reboiler, the feed evaporator, the rectification column reboiler and the deacidification column reboiler, and the condensate outlets of the four plants are connected to the condensate inlet of the hot water tank. The overhead steam outlet of the fifth concentration tower is connected to the steam inlet of the fourth concentration tower reboiler, and the steam outlet of the fourth concentration tower and the steam of the third concentration tower reboiler The mouth is connected, the overhead steam outlet of the third concentration tower is connected to the steam inlet of the second concentration tower reboiler, and the overhead steam outlet of the second concentration tower is connected to the steam inlet of the first concentration tower reboiler, the first concentration The overhead steam outlet of the column is connected to the steam inlet of the overhead condenser, and the condensate outlet of the overhead condenser is connected to the condensate inlet of the first concentration tank overhead tank. The overhead steam outlet of the rectification column is connected to the steam inlet of the top condenser of the rectification column, and the condensate outlet of the top condenser of the rectification column is connected to the condensate inlet of the top tank of the rectification column. The overhead DMAC (DMF) vapor outlet of the deacidification column is connected to the steam inlet of the DMAC (DMF) condenser, and the finished product outlet of the DMAC (DMF) condenser is connected to the finished product inlet of the DMAC (DMF) reflux tank.
10. The apparatus for recovering a seven-column five-effect rectification system and a recovery method for a DMAC (DMF) waste liquid according to claim 5, comprising: a first concentration tower, a second concentration tower, a third concentration tower, and a first a water ring vacuum pump of a fourth concentration tower, a fifth concentration tower, and a rectification tower;

    The vacuum ports of the first concentration tower, the second concentration tower, the third concentration tower, the fourth concentration tower, the fifth concentration tower, and the rectification tower are connected to the inlets of the respective water ring vacuum pumps, and the gas outlets of the water ring vacuum pumps are The air inlet of the gas water separation tank is connected.

Images