Copolymerized polyester waste treatment system

Abstract

The utility model relates to the technical field of waste gas and waste liquid treatment, in particular to a copolyester waste treatment system which sequentially comprises a copolyester waste storage tank, a heat exchanger, a stripping tower and an organic waste gas incinerator according to the flowing direction of copolyester waste, the copolymerized polyester waste treatment system disclosed by the utility model can be used for efficiently treating waste gas and waste liquid generated in a copolymerized polyester production process at the same time, so that potential safety hazards existing in the production process are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of waste gas and waste liquid treatment, in particular to a copolymer polyester waste material treatment system. Background Art

[0002] Copolyester (Z-resin) is a new series of transparent engineering plastics, a perfect combination of high transparency, high impact resistance and high chemical resistance. This material is highly transparent, highly impact resistant, has excellent fluidity, chemical resistance, can be electroplated, sprayed with oil, and scratch resistant. The density is 16% lower than PC (polycarbonate), and the processing cost is 40% lower than PC. It has good printing, coloring and electroplating performance, and its toughness is 3 times higher than transparent ABS. It complies with the European RoHS environmental protection directive. It is suitable for high-end cosmetics, electronic and electrical internal materials, toys, high-end pens, and can replace PC in various fields. PCTA is a highly transparent copolyester plastic raw material. It has high transparency, good toughness and impact strength, excellent low-temperature toughness, high tear resistance and good processing performance, and excellent chemical resistance. It can be processed by traditional extrusion, injection molding, blow molding and blister molding methods. It is widely used in the market of sheet materials, high-performance shrink films, bottles and special-shaped materials; it can be used to produce toys, household utensils and medical supplies; it has passed the US FDA's food contact standards and can be used in food, medicine, cosmetics packaging and other fields.

[0003] Copolyester will produce waste gas and waste liquid containing by-products during the production process, especially the esterification process. The waste gas contains a large amount of pungent organic volatile vapors such as benzoic acid, phenol, acetaldehyde, etc. When the entire system is affected by maintenance, start-up and shutdown, the treatment of waste gas and waste liquid will be particularly difficult. In particular, the COD value in the waste liquid will also rise rapidly. Traditional treatment methods may control the COD value through biochemical treatment systems or adding mixed water, but these treatment methods are not effective enough. In particular, factors such as sudden weather changes or temperature out of control will cause the process state of the anaerobic system biochemical treatment to fluctuate greatly, and the treatment efficiency will decrease. In severe cases, the entire treatment system will be paralyzed.

[0004] CN103768823A discloses a method for resource recovery of unsaturated polyester waste gas. The method comprises: (1) the polyester waste gas first enters a condenser for condensation, so that the organic matter in the waste gas with a boiling point higher than water is transferred from the gas phase to the liquid phase, and the organic matter therein is recovered; (2) the uncondensed waste gas is mixed and dried with air and / or circulating reflux tail gas in a dryer to remove the entrained moisture, and then enters a preheater; (3) the preheated waste gas enters a catalytic combustion reactor to contact with a catalyst for reaction, and the reaction tail gas is directly used as a dilution gas to recover heat. However, this technical solution can only recover high-boiling-point, non-volatile organic matter in the waste gas, and cannot treat the waste liquid generated in the production process of copolymerized polyester. Therefore, it is necessary to add another waste liquid treatment device, which is costly and the coordination between the various devices also requires strict design.

[0005] CN201746348U A stripping tower device for reducing the COD value of polyester wastewater, characterized in that it includes a wastewater collection tank, a first chemical pump, a heat exchanger, a second chemical pump, a stripping tower and a heat medium furnace; the outlet of the wastewater collection tank is connected to the inlet of the first chemical pump, the outlet of the first chemical pump is connected to the inlet of the heat exchanger, the outlet of the heat exchanger is connected to the inlet of the top of the stripping tower, the outlet of the bottom of the stripping tower is connected to the inlet of the second chemical pump, the outlet of the second chemical pump is connected to the heat exchange medium inlet of the heat exchanger or directly connected to the sewage treatment station, and the heat exchange medium outlet of the heat exchanger is connected to the sewage treatment station; the gas outlet at the top of the stripping tower is connected to the heat medium furnace. In this technical solution, the waste gas treated by the stripping tower is then burned in the heat medium furnace, and in the process of combustion, it is in an oxygen-free environment, that is, nitrogen is added. However, for waste gas, the oxygen-free combustion condition will lead to incomplete combustion, and it will not be able to meet the emission standards, causing irreversible environmental impact on the atmosphere, that is, this technical solution still cannot solve the rationalization and environmentally friendly treatment of copolymerized polyester waste gas in the prior art.

[0006] In the prior art, RCO (Regenerative Catalytic Oxidation Oxidation) furnaces are also used, that is, regenerative catalytic combustion methods are used to treat the above-mentioned waste gas. The working principle of the RCO regenerative catalytic combustion method is: the first step is the adsorption of VOC molecules by the catalyst, which increases the concentration of the reactants, and the second step is to reduce the activation energy of the reaction in the catalytic oxidation stage, thereby increasing the reaction rate. With the help of catalysts, organic waste gas can be burned without oxygen at a lower ignition temperature, decomposed into CO2 and H2O, and release a large amount of heat. Compared with direct combustion, it has the characteristics of low ignition temperature and low energy consumption. In some cases, no external heat is required after reaching the ignition temperature, and the reaction temperature is 250-400°C. When preparing copolyester, the waste gas generated in the esterification and vacuum system contains pollutants such as THF and acetaldehyde, while the existing RCO furnace can only treat THF waste gas, but cannot treat acetaldehyde, that is, the waste gas treatment capacity is limited, and the waste liquid generated by the copolyester cannot be treated. At the same time, the COD value of the waste liquid generated by the polyester system is too high, which will increase the cost of sewage treatment and affect the ability of sewage to treat other sewage.

[0007] CN207716435U discloses a polyester wastewater and waste gas recovery and treatment device, which mainly includes a workshop recyclable wastewater storage tank and a recycling material storage tank, a chimney and a pipeline. A filter, a distillation kettle, a distillation tower and a combustion furnace are arranged on the pipeline connecting the wastewater storage tank; the distillation tower is connected to the distillation kettle and the combustion furnace, and the distillation kettle is connected to a primary tail gas heat exchanger and a secondary tail gas heat exchanger through a pipeline; the upper part of the furnace of the incinerator is opened, and is connected to the distillation tower through a pipeline, and a water receiver is also connected to the pipeline through a small pipeline, and the water receiver is connected to the recyclable wastewater storage tank; the pipeline connected to the recycling material storage tank is connected to the primary heat exchanger and the secondary heat exchanger. The combustion furnace in this technical solution is a high-temperature incinerator. It can be seen from the drawings in the specification of this patent that it uses natural gas, and heat transfer oil is also required as a heat medium during the incineration process. Therefore, this technical solution has a high risk and is not conducive to placement in the production line of plastics such as copolyester, which is easy to cause fire and uncontrollable accidents.

[0008] Based on the above situation, the existing technology cannot efficiently treat the waste gas and waste liquid generated in the production process of copolymer polyester, and there are also high safety hazards and other technical problems that need to be solved urgently. Utility Model Content

[0009] In order to solve the above technical problems, the utility model provides a copolyester waste treatment system, which includes a copolyester waste storage tank, a heat exchanger, a stripping tower, and an organic waste gas incinerator (TO furnace) in sequence according to the flow direction of the copolyester waste;

[0010] The outlet of the copolyester waste storage tank is connected to the first inlet of the heat exchanger, the first outlet of the heat exchanger is connected to the waste inlet of the stripping tower, the waste liquid outlet of the stripping tower is connected to the second inlet of the heat exchanger, and the waste gas outlet of the stripping tower is connected to the waste gas inlet of the organic waste gas incinerator; the stripping tower is provided with a steam inlet;

[0011] The first inlet of the heat exchanger is in communication with the first outlet of the heat exchanger, and the second inlet of the heat exchanger is in communication with the second outlet of the heat exchanger.

[0012] Furthermore, a first wastewater pump is provided between the copolyester waste storage tank and the heat exchanger, the outlet of the copolyester waste storage tank is connected to the inlet of the first wastewater pump, the outlet of the first wastewater pump is connected to the first inlet of the heat exchanger, and the first wastewater pump provides power for the copolyester waste in the copolyester waste storage tank to smoothly pump it into the heat exchanger for heat exchange.

[0013] Furthermore, a buffer tank is provided between the stripping tower and the organic waste gas incinerator, the waste gas outlet of the stripping tower is connected to the inlet of the buffer tank, the outlet of the buffer tank is connected to the waste gas inlet of the organic waste gas incinerator, and the buffer tank is used to store and buffer the waste gas discharged from the stripping tower;

[0014] The buffer tank is used to control the continuity and stability of waste gas treatment. Even if the waste gas emissions from the stripping tower suddenly increase, it will not cause impact on the subsequent organic waste gas incinerator. At the same time, when the waste gas emissions fluctuate, the buffer tank can absorb the energy generated by the fluctuation, ensuring that the subsequent organic waste gas incinerator can obtain relatively stable waste gas flow and pressure, thereby extending the service life of the organic waste gas incinerator, reducing the maintenance frequency, and reducing maintenance costs.

[0015] Furthermore, the system also includes an oxygen supplementation fan connected to the organic waste gas incinerator, the outlet of the oxygen supplementation fan is connected to the air inlet of the organic waste gas incinerator, the air enters the oxygen supplementation fan from the inlet of the oxygen supplementation fan, and enters the organic waste gas incinerator through the outlet of the oxygen supplementation fan and the air inlet of the organic waste gas incinerator in turn, and contacts with the waste gas of the organic waste gas incinerator. The oxygen supplementation fan is used to provide oxygen to the organic waste gas incinerator to ensure complete combustion and efficient treatment of the waste gas.

[0016] Furthermore, a second wastewater pump is provided between the heat exchanger and the stripping tower, the waste liquid outlet of the stripping tower is connected to the inlet of the second wastewater pump, the outlet of the second wastewater pump is connected to the second inlet of the heat exchanger, and the second wastewater pump provides power for the stripped waste liquid flowing out from the bottom of the stripping tower, pumping it into the heat exchanger for heat exchange with the copolyester waste, thereby increasing the temperature of the copolyester waste and reducing the temperature of the waste liquid itself.

[0017] Furthermore, the heat exchanger is a plate heat exchanger.

[0018] Furthermore, the stripping tower is a plate tower or a packed tower.

[0019] The beneficial effects of the utility model are:

[0020] The utility model provides a copolyester waste treatment system, which includes a copolyester waste storage tank, a heat exchanger, a stripping tower, and an organic waste gas incinerator (TO furnace) in sequence according to the flow direction of the copolyester waste;

[0021] The outlet of the copolyester waste storage tank is connected to the first inlet of the heat exchanger, the first outlet of the heat exchanger is connected to the waste inlet of the stripping tower, the waste liquid outlet of the stripping tower is connected to the second inlet of the heat exchanger, and the waste gas outlet of the stripping tower is connected to the waste gas inlet of the organic waste gas incinerator; the stripping tower is provided with a steam inlet;

[0022] The first inlet of the heat exchanger is in communication with the first outlet of the heat exchanger, and the second inlet of the heat exchanger is in communication with the second outlet of the heat exchanger;

[0023] The copolyester waste treatment system provided by the utility model is that after the copolyester waste enters the copolyester waste storage tank, it enters the heat exchanger through the outlet of the copolyester waste storage tank for heat exchange, and the temperature of the copolyester waste is increased. The heated copolyester waste is discharged from the first outlet of the heat exchanger, and then enters the stripping tower from the waste inlet located at the top of the stripping tower, and is reversely contacted with the steam entering from the steam inlet located in the middle of the stripping tower for stripping, and is divided into waste liquid and waste gas;

[0024] The waste gas is discharged from the waste gas outlet at the top of the stripping tower, sent to the organic waste gas incinerator for incineration and decomposition, and then emptied; the waste liquid is discharged from the waste liquid outlet at the bottom of the stripping tower, sent to the heat exchanger for heat exchange with a new batch of copolyester waste entering the heat exchanger for heat exchange, so as to reduce the temperature of the waste liquid, and the waste liquid after cooling can be directly sent to the sewage treatment plant for direct treatment;

[0025] The copolyester waste treatment system of the utility model can simultaneously and efficiently treat waste gas and waste liquid generated in the copolyester production process, thereby reducing potential safety hazards in the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a process flow chart of a copolymerized polyester waste treatment system in Example 1 of the utility model;

[0027] The labels in the figure are:

[0028] 1. Copolyester waste storage tank; 2. Heat exchanger; 3. Stripping tower; 4. Organic waste gas incinerator; 5. First wastewater pump; 6. Buffer tank; 7. Oxygen supplement fan; 8. Second wastewater pump; A. Copolyester waste; A1. Waste liquid; A2. Waste gas; B. Steam; C. Air. DETAILED DESCRIPTION

[0029] Example 1

[0030] like Figure 1 As shown, this embodiment provides a copolyester waste treatment system, which includes a copolyester waste storage tank 1, a heat exchanger 2, a stripping tower 3, and an organic waste gas incinerator 4 (TO furnace) in sequence according to the flow direction of the copolyester waste A;

[0031] The outlet of the copolyester waste storage tank 1 is connected to the first inlet of the heat exchanger 2, the first outlet of the heat exchanger 2 is connected to the waste inlet of the stripping tower 3, the waste liquid outlet of the stripping tower 3 is connected to the second inlet of the heat exchanger 2, and the waste gas outlet of the stripping tower 3 is connected to the waste gas inlet of the organic waste gas incinerator 4; the stripping tower 3 is provided with a steam inlet;

[0032] The first inlet of the heat exchanger 2 is communicated with the first outlet of the heat exchanger 2 , and the second inlet of the heat exchanger 2 is communicated with the second outlet of the heat exchanger 2 .

[0033] In the copolyester waste treatment system provided in this embodiment, copolyester waste A is used to verify the system. The temperature of copolyester waste A is room temperature and the COD value is 1200 mg / L. The copolyester waste A includes water, ethylene glycol, acetaldehyde, and other organic matter, wherein the flow rate of water is 1432.4 kg / h, the flow rate of ethylene glycol is 4.5 kg / h, the flow rate of acetaldehyde is 41.2 kg / h, and the total flow rate of other organic matter is 2 kg / h.

[0034] After the copolyester waste A enters the copolyester waste storage tank 1, it enters the heat exchanger 2 through the outlet of the copolyester waste storage tank 1 for heat exchange, and the temperature of the copolyester waste A is increased to 50° C. The heated copolyester waste A is discharged from the first outlet of the heat exchanger 2, and then enters the stripping tower 3 from the waste inlet located at the top of the stripping tower 3, and is counter-contacted with the steam B entering from the steam inlet located in the middle of the stripping tower 3 for stripping, and is divided into waste liquid A1 and waste gas A2, and the COD value of the waste liquid A1 is reduced to 300 mg / L during the stripping process;

[0035] The waste gas A2 is discharged from the waste gas outlet at the top of the stripping tower 3, and sent to the organic waste gas incinerator 4 for incineration and decomposition, and is directly discharged after being decomposed into carbon dioxide and water, wherein the decomposition rate of the waste gas A2 is 98%; the waste liquid A1 is discharged from the waste liquid outlet at the bottom of the stripping tower 3, and sent to the heat exchanger 2 for heat exchange with a new batch of copolyester waste A entering the heat exchanger 2 for heat exchange, so as to achieve production continuity and reduce the temperature of the waste liquid A1 to 25°C. The cooled waste liquid A1 can be directly sent to the sewage treatment plant for subsequent treatment.

[0036] In this embodiment, if Figure 1 As shown, a first wastewater pump 5 is further provided between the copolyester waste storage tank 1 and the heat exchanger 2, the outlet of the copolyester waste storage tank 1 is connected to the inlet of the first wastewater pump 5, the outlet of the first wastewater pump 5 is connected to the first inlet of the heat exchanger 2, and the first wastewater pump 5 provides power for the copolyester waste A in the copolyester waste storage tank 1 to smoothly pump it into the heat exchanger 2 for heat exchange.

[0037] A buffer tank 6 is further provided between the stripping tower 3 and the organic waste gas incinerator 4. The waste gas outlet of the stripping tower 3 is connected to the inlet of the buffer tank 6, and the outlet of the buffer tank 6 is connected to the waste gas inlet of the organic waste gas incinerator 4. The buffer tank 6 is used to store and buffer the waste gas A2 discharged from the stripping tower 3;

[0038] The buffer tank 6 is used to control the continuity and stability of the waste gas A2 treatment. Even if the waste gas A2 emissions from the stripping tower 3 suddenly increase, it will not cause impact on the subsequent organic waste gas incinerator 4. At the same time, when the waste gas A2 emissions fluctuate, the buffer tank 6 can absorb the energy generated by the fluctuation, ensuring that the subsequent organic waste gas incinerator 4 can obtain a relatively stable waste gas A2 flow and pressure, thereby extending the service life of the organic waste gas incinerator 4, reducing the maintenance frequency, and reducing the maintenance cost.

[0039] The system also includes an oxygen supplement fan 7 connected to the organic waste gas incinerator 4, and the outlet of the oxygen supplement fan 7 is connected to the air inlet of the organic waste gas incinerator 4. Air C enters the oxygen supplement fan 7 from the inlet of the oxygen supplement fan 7, and enters the organic waste gas incinerator 4 through the outlet of the oxygen supplement fan 7 and the air inlet of the organic waste gas incinerator 4 in turn, and contacts the waste gas A2 of the organic waste gas incinerator 4. The oxygen supplement fan 7 is used to provide oxygen to the organic waste gas incinerator 4 to ensure complete combustion and efficient treatment of the waste gas A2.

[0040] A second wastewater pump 8 is also provided between the heat exchanger 2 and the stripping tower 3. The waste liquid outlet of the stripping tower 3 is connected to the inlet of the second wastewater pump 8. The outlet of the second wastewater pump 8 is connected to the second inlet of the heat exchanger 2. The second wastewater pump 8 provides power for the stripped waste liquid A1 flowing out from the bottom of the stripping tower 3, and pumps it into the heat exchanger 2 for heat exchange with the copolyester waste A, thereby increasing the temperature of the copolyester waste A while reducing the temperature of the waste liquid A1 itself. When the copolyester waste A is fed for the first time, steam heating is used to increase the temperature of the copolyester waste A.

[0041] In this embodiment, the heat exchanger 2 is a plate heat exchanger; the stripping tower 3 is a plate tower. In some embodiments, the stripping tower 3 is a packed tower.

[0042] It can be seen that the copolyester waste treatment system provided in this embodiment can efficiently treat the waste gas and waste liquid generated in the copolyester production process at the same time, thereby reducing the potential safety hazards in the production process.

[0043] It should be understood that the present invention is not limited to what has been described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A copolyester waste treatment system, characterized in that: According to the flow direction of the copolyester waste, the system comprises, in sequence, a copolyester waste storage tank (1), a heat exchanger (2), a stripping tower (3), and an organic waste gas incinerator (4); The outlet of the copolyester waste storage tank (1) is connected to the first inlet of the heat exchanger (2), the first outlet of the heat exchanger (2) is connected to the waste inlet of the stripping tower (3), the waste liquid outlet of the stripping tower (3) is connected to the second inlet of the heat exchanger (2), and the waste gas outlet of the stripping tower (3) is connected to the waste gas inlet of the organic waste gas incinerator (4); the stripping tower (3) is provided with a steam inlet; The first inlet of the heat exchanger (2) is in communication with the first outlet of the heat exchanger (2), and the second inlet of the heat exchanger (2) is in communication with the second outlet of the heat exchanger (2).

2. The copolyester waste treatment system according to claim 1, characterized in that: A first wastewater pump (5) is also provided between the copolyester waste storage tank (1) and the heat exchanger (2); the outlet of the copolyester waste storage tank (1) is connected to the inlet of the first wastewater pump (5); and the outlet of the first wastewater pump (5) is connected to the first inlet of the heat exchanger (2).

3. The copolyester waste treatment system according to claim 1, characterized in that: A buffer tank (6) is further provided between the stripping tower (3) and the organic waste gas incinerator (4); the waste gas outlet of the stripping tower (3) is connected to the inlet of the buffer tank (6), and the outlet of the buffer tank (6) is connected to the waste gas inlet of the organic waste gas incinerator (4).

4. The copolyester waste treatment system according to claim 1, characterized in that: The system further comprises an oxygen-supplementing fan (7) connected to the organic waste gas incinerator (4), and an outlet of the oxygen-supplementing fan (7) is connected to an air inlet of the organic waste gas incinerator (4).

5. The copolyester waste treatment system according to claim 1, characterized in that: A second wastewater pump (8) is also provided between the heat exchanger (2) and the stripping tower (3); the waste liquid outlet of the stripping tower (3) is connected to the inlet of the second wastewater pump (8); and the outlet of the second wastewater pump (8) is connected to the second inlet of the heat exchanger (2).

6. The copolyester waste treatment system according to claim 1, characterized in that: The heat exchanger (2) is a plate heat exchanger.

7. The copolyester waste treatment system according to claim 1, characterized in that: The stripping tower (3) is a plate tower or a packed tower.

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