CN114873671A - Device and method for treating DMF (dimethyl formamide) wastewater by triple-effect heat pump rectification method - Google Patents
Device and method for treating DMF (dimethyl formamide) wastewater by triple-effect heat pump rectification method Download PDFInfo
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
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- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/52—Heat recovery pumps, i.e. heat pump based systems or units able to transfer the thermal energy from one area of the premises or part of the facilities to a different one, improving the overall efficiency
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Abstract
The invention relates to a device and a method for treating DMF (dimethyl formamide) wastewater by a triple-effect heat pump rectification method. The device comprises a primary micro-positive pressure rectifying system, a secondary micro-positive pressure rectifying system, a tertiary low-pressure rectifying system and a raw material preheating system; wherein the first-stage micro-positive pressure rectifying system, the second-stage micro-positive pressure rectifying system and the third-stage low-pressure rectifying system are connected in series in sequence. According to the invention, DMF in wastewater is recycled by connecting three rectifying towers in series, and the energy of steam at the top of the rectifying tower is recycled by a heat pump, so that the energy-saving effect is fully exerted. Compared with the traditional three-tower rectification process for treating DMF wastewater, the method can save the energy consumption by 10-20%, and has obvious economic benefit.
Description
Technical Field
The invention belongs to the field of chemical waste solvent treatment and recovery, and particularly relates to a device and a method for treating DMF (dimethyl formamide) wastewater by a triple-effect heat pump rectification method.
Background
DMF full scaleN，NDimethylformamide is a common organic solvent and chemical raw material, can be completely mutually dissolved with various substances such as water, ether, alcohol and the like, and has wide application in the fields of medicine, leather making, petrochemical industry, organic synthesis and the like. In the field of preparing synthetic leather by a PU method, DMF is used as a solvent of PU resin in a large amount. In the production of synthetic leather, DMF is only used as a solvent and does not participate in chemical reaction, so most of DMF enters production wastewater after the production process is finished, and a large amount of DMF-containing wastewater is generated.
DMF is relatively expensive and toxic, and can enter human body through skin and respiratory tract to cause damage to various organs of human body such as liver and kidney. If the DMF waste water is directly discharged, environmental damage and economic loss are caused, so the DMF waste water must be treated to recover DMF therein.
At present, the main mode for recycling DMF in wastewater in the synthetic leather industry is a rectification method, and DMF in wastewater is separated and recycled through rectification. The commonly used rectifying process comprises three-tower rectification and two-tower rectification, and although the multi-effect utilization of steam is realized, the total energy consumption is still larger, and 80% of the cost of DMF recovery is used for the heat energy consumption of rectification. In order to achieve the energy-saving effect, a double-effect heat pump is used in CN 106748864 a, and the heat pump is used for supplying energy to the tower kettle after raising the temperature of the steam at the top of the rectifying tower, but the pressure in the rectifying tower in the process is low and is only 0.02 MPa, and a common steam compressor is not suitable for compressing the steam within the pressure range and lacks operability. CN104130152A adopts double-effect heat pump rectification, firstly uses a flash tank to concentrate DMF wastewater, then obtains a product through a vacuum rectification tower, in the process, the tower kettle discharge of the vacuum rectification tower is compressed by a compressor to preheat the wastewater feed, and then the tower kettle discharge is used as a cold source to cool the flash tank tower top steam after preheating, and the process does not realize energy saving through a heat pump.
Disclosure of Invention
In order to solve the problem of high energy consumption in DMF rectification recovery, the invention provides a device and a method for treating DMF wastewater by a triple-effect heat pump rectification method.
A device for treating DMF wastewater by a triple-effect heat pump rectification method comprises a first-stage micro-positive pressure rectification system, a second-stage micro-positive pressure rectification system, a third-stage low-pressure rectification system and a raw material preheating system; wherein the primary micro-positive pressure rectification system, the secondary micro-positive pressure rectification system and the tertiary low-pressure rectification system are connected in series in sequence;
the first-stage micro-positive pressure rectification system comprises a first rectification tower, a first mechanical vapor compressor, a first rectification tower reboiler and a first rectification tower kettle liquid pump;
the two-stage micro-positive pressure rectification system comprises a second rectification tower, a second mechanical vapor compressor, a second rectification tower reboiler, a second rectification tower kettle liquid pump and a first condensate pump;
the three-stage low-pressure rectification system comprises a third rectification tower, a third rectification tower reboiler, a third rectification tower kettle liquid pump and a second condensate pump;
the raw material preheating system comprises a first heat exchanger which is respectively connected with the first rectifying tower and the third rectifying tower.
In the primary micro-positive pressure rectification system, a first rectification tower reboiler is positioned at one side of a first rectification tower, a first rectification tower kettle liquid pump is positioned at the bottom of the first rectification tower, and a first mechanical vapor compressor is positioned at the top of the first rectification tower;
in the two-stage micro-positive pressure rectification system, a reboiler of the second rectification tower is positioned on one side of the second rectification tower, a kettle liquid pump of the second rectification tower is positioned at the bottom of the second rectification tower, and a second mechanical vapor compressor is positioned at the top of the second rectification tower; a first condensate pump is arranged at the bottom of the reboiler of the second rectifying tower;
in the three-stage low-pressure rectification system, a reboiler of a third rectification tower is positioned at one side of the third rectification tower, and a kettle liquid pump of the third rectification tower is positioned at the bottom of the third rectification tower; a second condensate pump is arranged at the bottom of the reboiler of the third rectifying tower; the first mechanical vapor compressor is connected with the second rectifying tower reboiler, and the second mechanical vapor compressor is connected with the third rectifying tower reboiler; the first rectifying tower liquid tank pump is connected with the second rectifying tower, and the second rectifying tower liquid tank pump is connected with the third rectifying tower.
A triple-effect heat pump rectification method for DMF waste liquid recovery adopts the device and comprises the following steps:
1) preheating DMF wastewater by a preheater and then feeding the preheated DMF wastewater into a first rectifying tower;
2) after DMF wastewater enters a first rectifying tower and is rectified, tower top steam obtained by the first rectifying tower is compressed by a first mechanical vapor compressor and then is sent to a reboiler of a second rectifying tower of the second rectifying tower, and obtained condensed water partially flows back to the first rectifying tower after passing through a first condensed water pump; part of the first rectifying tower bottom concentrated solution is heated by a first rectifying tower reboiler and then is sent back to the first rectifying tower, and part of the first rectifying tower bottom concentrated solution is sent into a second rectifying tower through a first rectifying tower bottom liquid pump;
3) after the DMF concentrated wastewater entering the second rectifying tower is rectified, the tower top vapor of the second rectifying tower is compressed by a second mechanical vapor compressor and then is sent to a reboiler of a third rectifying tower, the obtained condensed water partially flows back to the second rectifying tower after passing through a second condensed water pump, part of concentrated solution at the bottom of the second rectifying tower is heated by the reboiler of the second rectifying tower and then is sent back to the second rectifying tower, and the other part of the concentrated solution is sent to the third rectifying tower through a tower residue pump of the second rectifying tower;
4) after the DMF concentrated wastewater entering the third rectifying tower is rectified, the tower top steam of the third rectifying tower is sent to a raw material preheater for preheating the raw material DMF wastewater, one part of the concentrated solution at the bottom of the third rectifying tower is heated by a reboiler of the third rectifying tower and then sent back to the third rectifying tower, and the other part of the concentrated solution is sent out as a product through a kettle liquid pump of the third rectifying tower.
The DMF wastewater passes through a preheating system before flowing into the first rectifying tower, and a heat flow strand of the preheating system comes from the overhead steam of the third rectifying tower.
The first rectifying tower is a positive pressure rectifying tower, the operating temperature is 100-115 ℃, the operating pressure is 0.1-0.13 MPa, and the reflux ratio at the top of the tower is 0.5-3.
The second rectifying tower is a positive pressure rectifying tower, the operating temperature is 100-115 ℃, the operating pressure is 0.1-0.13 MPa, and the reflux ratio at the top of the tower is 0.5-3.
The third rectifying tower is a negative pressure rectifying tower, the operating temperature is 70-115 ℃, the operating pressure is 0.01-0.03 MPa, and the reflux ratio at the top of the tower is 0.7-3.
The invention has the beneficial effects that:
compared with the prior art, the invention recovers the energy in the steam at the top of the tower by using the heat pump, obviously saves the energy consumption, can save the energy consumption by 10 to 20 percent compared with the traditional three-tower rectification process, has obvious economic benefit, and simultaneously fully utilizes the existing three-tower rectification process equipment, can fully utilize the old equipment and save the investment cost.
Drawings
FIG. 1 is a schematic diagram of the apparatus of the present invention;
in the figure, a first rectifying tower (1-1), a first mechanical vapor compressor (1-2), a first rectifying tower reboiler (1-3), a first rectifying tower kettle liquid pump (1-4), a second rectifying tower (2-1), a second mechanical vapor compressor (2-2), a second rectifying tower reboiler (2-3), a second rectifying tower kettle liquid pump (2-4), a first condensate water pump (2-5), a third rectifying tower (3-1), a third rectifying tower reboiler (3-3), a third rectifying tower kettle liquid pump (3-4), a second condensate water pump (3-5) and a first heat exchanger (4-1).
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
As shown in figure 1, the device for treating DMF wastewater by a triple-effect heat pump rectification method comprises a first-stage micro-positive pressure rectification system, a second-stage micro-positive pressure rectification system, a third-stage low-pressure rectification system and a raw material preheating system; wherein the primary micro-positive pressure rectification system, the secondary micro-positive pressure rectification system and the tertiary low-pressure rectification system are connected in series in sequence;
the primary micro-positive pressure rectification system comprises a first rectification tower (1-1), a first mechanical vapor compressor (1-2), a first rectification tower reboiler (1-3) and a first rectification tower kettle liquid pump (1-4);
the two-stage micro-positive pressure rectification system comprises a second rectification tower (2-1), a second mechanical vapor compressor (2-2), a second rectification tower reboiler (2-3), a second rectification tower kettle liquid pump (2-4) and a first condensate pump (2-5);
the three-stage low-pressure rectification system comprises a third rectification tower (3-1), a third rectification tower reboiler (3-3), a third rectification tower kettle liquid pump (3-4) and a second condensate pump (3-5);
the raw material preheating system comprises a first heat exchanger (4-1) which is respectively connected with a first rectifying tower (1-1) and a third rectifying tower (3-1).
In the primary micro-positive pressure rectification system, a first rectification tower reboiler (1-3) is positioned at one side of a first rectification tower (1-1), a first rectification tower kettle liquid pump (1-4) is positioned at the bottom of the first rectification tower (1-1), and a first mechanical vapor compressor (1-2) is positioned at the top of the first rectification tower (1-1);
in the two-stage micro-positive pressure rectification system, a second rectification tower reboiler (2-3) is positioned at one side of a second rectification tower (2-1), a second rectification tower kettle liquid pump (2-4) is positioned at the bottom of the second rectification tower (2-1), and a second mechanical vapor compressor (2-2) is positioned at the top of the second rectification tower (2-1); a first condensate pump (2-5) is arranged at the bottom of the second rectifying tower reboiler (2-3);
in the three-stage low-pressure rectification system, a third rectification tower reboiler (3-3) is positioned at one side of a third rectification tower (3-1), and a third rectification tower kettle liquid pump (3-4) is positioned at the bottom of the third rectification tower (3-1); a second condensate pump (3-5) is arranged at the bottom of the third rectifying tower reboiler (2-3); the first mechanical vapor compressor (1-2) is connected with the second rectifying tower reboiler (2-3), and the second mechanical vapor compressor (2-2) is connected with the third rectifying tower reboiler (3-3); the first rectifying tower liquid tank pump (1-4) is connected with the second rectifying tower (2-1), and the second rectifying tower liquid tank pump (2-4) is connected with the third rectifying tower (3-1).
A triple-effect heat pump rectification method for DMF waste liquid recovery adopts the device and comprises the following steps:
1) the DMF wastewater enters a first rectifying tower (1-1) after being preheated by a preheater (4-1);
2) after DMF wastewater enters a first rectifying tower (1-1) to be rectified, tower top steam obtained by the first rectifying tower (1-1) is compressed by a first mechanical vapor compressor (1-2) and then is sent to a second rectifying tower reboiler (2-3) of a second rectifying tower (2-1), and obtained condensed water partially flows back to the first rectifying tower (1-1) after passing through a first condensed water pump (2-5); one part of concentrated solution at the bottom of the first rectifying tower (1-1) is heated by a rectifying tower reboiler (1-3) of the first rectifying tower and then sent back to the first rectifying tower (1-1), and the other part of concentrated solution is sent to a second rectifying tower (2-1) through a first rectifying tower kettle liquid pump (1-4);
3) after the DMF concentrated wastewater entering a second rectifying tower (2-1) is rectified, the tower top vapor of the second rectifying tower (2-1) is compressed by a second mechanical vapor compressor (2-2) and then sent to a third rectifying tower reboiler (3-3), the obtained condensed water partially reflows to the second rectifying tower (2-1) after passing through a second condensed water pump (3-5), one part of the tower bottom concentrated solution of the second rectifying tower (2-1) is heated by the second rectifying tower reboiler (2-3) and then sent back to the second rectifying tower (2-1), and the other part of the tower bottom concentrated solution passes through a second rectifying tower kettle liquid pump (2-4) and then sent to the third rectifying tower (3-1);
4) after the DMF concentrated wastewater entering the third rectifying tower (3-1) is rectified, the tower top steam of the third rectifying tower (3-1) is sent to a raw material preheater (4-1) to preheat raw material DMF wastewater, part of the tower bottom concentrated solution of the third rectifying tower (3-1) is heated by a third rectifying tower reboiler (3-3) and then sent back to the third rectifying tower (3-1), and part of the tower bottom concentrated solution is sent out as a product through a third rectifying tower kettle liquid pump (3-4).
The DMF wastewater passes through a preheating system (4-1) before flowing into the first rectifying tower (1-1), and the heat flow of the preheating system comes from the overhead steam of the third rectifying tower (3-1).
The first rectifying tower (1-1) is a positive pressure rectifying tower, the operating temperature is 100-115 ℃, the operating pressure is 0.1-0.13 MPa, and the reflux ratio at the top of the tower is 0.5-3.
The second rectifying tower (2-1) is a positive pressure rectifying tower, the operating temperature is 100-115 ℃, the operating pressure is 0.1-0.13 MPa, and the reflux ratio at the top of the tower is 0.5-3.
The third rectifying tower (3-1) is a negative pressure rectifying tower, the operating temperature is 70-115 ℃, the operating pressure is 0.01-0.03 MPa, and the reflux ratio at the top of the tower is 0.7-3.
Example 1
1) DMF wastewater enters a rectifying tower (1-1) after being preheated by a preheater (4-1).
2) The temperature of the rectifying tower (1-1) is 100 ℃, the pressure is 0.1MPa, and the reflux ratio at the top of the tower is 0.5. Steam at the top of the rectifying tower (1-1) is heated by a steam compressor (1-2) to 15 ℃ and then enters a rectifying tower reboiler (2-3) to supply heat for the rectifying tower. A part of DMF concentrated wastewater obtained from the bottom of the rectifying tower (1-1) is sent to the rectifying tower (2-1) through a rectifying tower kettle liquid pump (1-4), and a part of DMF concentrated wastewater is heated by a rectifying tower reboiler (1-3) and then returns to the rectifying tower (1-1).
3) The temperature of the rectifying tower (2-1) is 100 ℃, the pressure is 0.1MPa, and the reflux ratio at the top of the tower is 0.5. The steam at the top of the rectifying tower (2-1) is heated by the vapor compressor (2-2) to 15 ℃ and then enters a rectifying tower reboiler (3-3) to supply heat for the rectifying tower. A part of DMF concentrated wastewater obtained from the bottom of the rectifying tower (2-1) is sent to the rectifying tower (3-1) through a rectifying tower kettle liquid pump (2-4), and a part of DMF concentrated wastewater is heated by a rectifying tower reboiler (2-3) and then returns to the rectifying tower (2-1).
4) The temperature of the rectifying tower (3-1) is 70 ℃, the pressure is 0.01MPa, and the reflux ratio at the top of the tower is 0.7. The steam at the top of the rectifying tower (3-1) enters a heat exchanger (4-1) to supply heat for the rectifying tower. Part of DMF obtained at the bottom of the rectifying tower (3-1) is sent out as a product by a rectifying tower kettle liquid pump (3-4), and part of DMF is heated by a rectifying tower reboiler (3-3) and then returns to the rectifying tower (3-1).
Example 2
1) The DMF wastewater enters a rectifying tower (1-1) after being preheated by a preheater (4-1).
2) The temperature of the rectifying tower (1-1) is 115 ℃, the pressure is 0.13MPa, and the reflux ratio at the top of the tower is 0.5. Steam at the top of the rectifying tower (1-1) is heated by a steam compressor (1-2) to 15 ℃ and then enters a rectifying tower reboiler (2-3) to supply heat for the rectifying tower. A part of DMF concentrated wastewater obtained from the bottom of the rectifying tower (1-1) is sent to the rectifying tower (2-1) through a rectifying tower kettle liquid pump (1-4), and a part of DMF concentrated wastewater is heated by a rectifying tower reboiler (1-3) and then returns to the rectifying tower (1-1).
3) The temperature of the rectifying tower (2-1) is 115 ℃, the pressure is 0.13MPa, and the reflux ratio at the top of the tower is 0.5. Steam at the top of the rectifying tower (2-1) is heated to 20 ℃ by the vapor compressor (2-2) and then enters a rectifying tower reboiler (3-3) to supply heat for the rectifying tower reboiler. A part of DMF concentrated wastewater obtained from the bottom of the rectifying tower (2-1) is sent to the rectifying tower (3-1) through a rectifying tower kettle liquid pump (2-4), and a part of DMF concentrated wastewater is heated by a rectifying tower reboiler (2-3) and then returns to the rectifying tower (2-1).
4) The temperature of the rectifying tower (3-1) is 115 ℃, the pressure is 0.03MPa, and the reflux ratio at the top of the tower is 0.7. The steam at the top of the rectifying tower (3-1) enters a heat exchanger (4-1) to supply heat for the rectifying tower. Part of DMF obtained at the bottom of the rectifying tower (3-1) is sent out as a product by a rectifying tower kettle liquid pump (3-4), and part of DMF is heated by a rectifying tower reboiler (3-3) and then returns to the rectifying tower (3-1).
Example 3
1) The DMF wastewater enters a rectifying tower (1-1) after being preheated by a preheater (4-1).
2) The temperature of the rectifying tower (1-1) is 100 ℃, the pressure is 0.1MPa, and the reflux ratio at the top of the tower is 3. Steam at the top of the rectifying tower (1-1) is heated by a steam compressor (1-2) to 15 ℃ and then enters a rectifying tower reboiler (2-3) to supply heat for the rectifying tower. A part of DMF concentrated wastewater obtained from the bottom of the rectifying tower (1-1) is sent to the rectifying tower (2-1) through a rectifying tower kettle liquid pump (1-4), and a part of DMF concentrated wastewater is heated by a rectifying tower reboiler (1-3) and then returns to the rectifying tower (1-1).
3) The temperature of the rectifying tower (2-1) is 100 ℃, the pressure is 0.1MPa, and the reflux ratio at the top of the tower is 3. The steam at the top of the rectifying tower (2-1) is heated by the vapor compressor (2-2) to 15 ℃ and then enters a rectifying tower reboiler (3-3) to supply heat for the rectifying tower. A part of DMF concentrated wastewater obtained from the bottom of the rectifying tower (2-1) is sent to the rectifying tower (3-1) through a rectifying tower kettle liquid pump (2-4), and a part of DMF concentrated wastewater is heated by a rectifying tower reboiler (2-3) and then returns to the rectifying tower (2-1).
4) The temperature of the rectifying tower (3-1) is 70 ℃, the pressure is 0.01MPa, and the reflux ratio at the top of the tower is 3. The steam at the top of the rectifying tower (3-1) enters a heat exchanger (4-1) to supply heat for the rectifying tower. Part of DMF obtained at the bottom of the rectifying tower (3-1) is sent out as a product by a rectifying tower kettle liquid pump (3-4), and part of DMF is heated by a rectifying tower reboiler (3-3) and then returns to the rectifying tower (3-1).
The embodiments in the above description can be further combined or replaced, and the embodiments are only described as preferred examples of the present invention, and do not limit the concept and scope of the present invention, and various changes and modifications made to the technical solution of the present invention by those skilled in the art without departing from the design concept of the present invention belong to the protection scope of the present invention. The scope of the invention is given by the appended claims and any equivalents thereof.
Claims (7)
1. A device for treating DMF wastewater by a triple-effect heat pump rectification method is characterized by comprising a first-stage micro-positive pressure rectification system, a second-stage micro-positive pressure rectification system, a third-stage low-pressure rectification system and a raw material preheating system; wherein the primary micro-positive pressure rectification system, the secondary micro-positive pressure rectification system and the tertiary low-pressure rectification system are connected in series in sequence;
the primary micro-positive pressure rectification system comprises a first rectification tower (1-1), a first mechanical vapor compressor (1-2), a first rectification tower reboiler (1-3) and a first rectification tower kettle liquid pump (1-4);
the two-stage micro-positive pressure rectification system comprises a second rectification tower (2-1), a second mechanical vapor compressor (2-2), a second rectification tower reboiler (2-3), a second rectification tower kettle liquid pump (2-4) and a first condensate pump (2-5);
the three-stage low-pressure rectification system comprises a third rectification tower (3-1), a third rectification tower reboiler (3-3), a third rectification tower kettle liquid pump (3-4) and a second condensate pump (3-5);
the raw material preheating system comprises a first heat exchanger (4-1) which is respectively connected with a first rectifying tower (1-1) and a third rectifying tower (3-1).
2. The device according to claim 1, wherein in the one-stage micro-positive pressure rectification system, the first rectification tower reboiler (1-3) is positioned at one side of the first rectification tower (1-1), the first rectification tower liquid kettle pump (1-4) is positioned at the bottom of the first rectification tower (1-1), and the first mechanical vapor compressor (1-2) is positioned at the top of the first rectification tower (1-1);
in the two-stage micro-positive pressure rectification system, a second rectification tower reboiler (2-3) is positioned at one side of a second rectification tower (2-1), a second rectification tower kettle liquid pump (2-4) is positioned at the bottom of the second rectification tower (2-1), and a second mechanical vapor compressor (2-2) is positioned at the top of the second rectification tower (2-1); a first condensate pump (2-5) is arranged at the bottom of the second rectifying tower reboiler (2-3);
in the three-stage low-pressure rectification system, a third rectification tower reboiler (3-3) is positioned at one side of a third rectification tower (3-1), and a third rectification tower kettle liquid pump (3-4) is positioned at the bottom of the third rectification tower (3-1); a second condensate pump (3-5) is arranged at the bottom of the third rectifying tower reboiler (2-3); the first mechanical vapor compressor (1-2) is connected with the second rectifying tower reboiler (2-3), and the second mechanical vapor compressor (2-2) is connected with the third rectifying tower reboiler (3-3); the first rectifying tower liquid tank pump (1-4) is connected with the second rectifying tower (2-1), and the second rectifying tower liquid tank pump (2-4) is connected with the third rectifying tower (3-1).
3. A triple-effect heat pump rectification method for DMF waste liquid recovery is characterized in that the device according to claim 1 or 2 is adopted, and the steps are as follows:
1) the DMF wastewater enters a first rectifying tower (1-1) after being preheated by a preheater (4-1);
2) after DMF wastewater enters a first rectifying tower (1-1) to be rectified, tower top steam obtained by the first rectifying tower (1-1) is compressed by a first mechanical vapor compressor (1-2) and then is sent to a second rectifying tower reboiler (2-3) of a second rectifying tower (2-1), and obtained condensed water partially flows back to the first rectifying tower (1-1) through the rear part of a first condensed water pump (2-5); one part of concentrated solution at the bottom of the first rectifying tower (1-1) is heated by a rectifying tower reboiler (1-3) of the first rectifying tower and then sent back to the first rectifying tower (1-1), and the other part of concentrated solution is sent to a second rectifying tower (2-1) through a first rectifying tower kettle liquid pump (1-4);
3) after the DMF concentrated wastewater entering a second rectifying tower (2-1) is rectified, the tower top vapor of the second rectifying tower (2-1) is compressed by a second mechanical vapor compressor (2-2) and then sent to a third rectifying tower reboiler (3-3), the obtained condensed water partially reflows to the second rectifying tower (2-1) after passing through a second condensed water pump (3-5), one part of the tower bottom concentrated solution of the second rectifying tower (2-1) is heated by the second rectifying tower reboiler (2-3) and then sent back to the second rectifying tower (2-1), and the other part of the tower bottom concentrated solution passes through a second rectifying tower kettle liquid pump (2-4) and then sent to the third rectifying tower (3-1);
4) after the DMF concentrated wastewater entering the third rectifying tower (3-1) is rectified, the tower top steam of the third rectifying tower (3-1) is sent to a raw material preheater (4-1) to preheat raw material DMF wastewater, part of the tower bottom concentrated solution of the third rectifying tower (3-1) is heated by a third rectifying tower reboiler (3-3) and then sent back to the third rectifying tower (3-1), and part of the tower bottom concentrated solution is sent out as a product through a third rectifying tower kettle liquid pump (3-4).
4. The triple-effect heat pump rectification method for DMF waste liquid recovery is characterized in that the DMF waste water flows through a preheating system (4-1) before flowing into the first rectification tower (1-1), and the heat flow of the preheating system is from the overhead steam of the third rectification tower (3-1).
5. The triple-effect heat pump rectification method for DMF waste liquid recovery according to claim 3, characterized in that the first rectification tower (1-1) is a positive pressure rectification tower, the operation temperature is 100-115 ℃, the operation pressure is 0.1-0.13 MPa, and the reflux ratio at the top of the tower is 0.5-3.
6. The triple-effect heat pump rectification method for DMF waste liquid recovery according to claim 3, characterized in that the second rectification tower (2-1) is a positive pressure rectification tower, the operation temperature is 100-115 ℃, the operation pressure is 0.1-0.13 MPa, and the reflux ratio at the top of the tower is 0.5-3.
7. The triple-effect heat pump rectification method for DMF waste liquid recovery according to claim 3, characterized in that the third rectification tower (3-1) is a negative pressure rectification tower, the operation temperature is 70-115 ℃, the operation pressure is 0.01-0.03 MPa, and the reflux ratio at the top of the tower is 0.7-3.
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| CN115382238A (en) * | 2022-08-24 | 2022-11-25 | 吉安巨联环保科技有限公司 | Method for reducing energy consumption of DMF waste liquid comprehensive utilization equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115382238A (en) * | 2022-08-24 | 2022-11-25 | 吉安巨联环保科技有限公司 | Method for reducing energy consumption of DMF waste liquid comprehensive utilization equipment |
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