CN221141493U - System for comprehensive treatment of polyoxymethylene wastewater - Google Patents
System for comprehensive treatment of polyoxymethylene wastewater Download PDFInfo
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- CN221141493U CN221141493U CN202322348404.7U CN202322348404U CN221141493U CN 221141493 U CN221141493 U CN 221141493U CN 202322348404 U CN202322348404 U CN 202322348404U CN 221141493 U CN221141493 U CN 221141493U
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- 239000002351 wastewater Substances 0.000 title claims abstract description 91
- 229920006324 polyoxymethylene Polymers 0.000 title claims abstract description 51
- 229930040373 Paraformaldehyde Natural products 0.000 title claims abstract description 49
- -1 polyoxymethylene Polymers 0.000 title claims abstract description 49
- 238000011282 treatment Methods 0.000 title description 22
- 239000007788 liquid Substances 0.000 claims abstract description 137
- 238000001704 evaporation Methods 0.000 claims abstract description 61
- 230000008020 evaporation Effects 0.000 claims abstract description 60
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 28
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 27
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 18
- 230000003647 oxidation Effects 0.000 claims abstract description 16
- 230000003197 catalytic effect Effects 0.000 claims abstract description 12
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000003513 alkali Substances 0.000 claims abstract description 11
- 239000012141 concentrate Substances 0.000 claims description 20
- 239000002826 coolant Substances 0.000 claims description 4
- 239000004280 Sodium formate Substances 0.000 abstract description 15
- HLBBKKJFGFRGMU-UHFFFAOYSA-M sodium formate Chemical compound [Na+].[O-]C=O HLBBKKJFGFRGMU-UHFFFAOYSA-M 0.000 abstract description 15
- 235000019254 sodium formate Nutrition 0.000 abstract description 15
- 239000000047 product Substances 0.000 abstract description 6
- 239000002699 waste material Substances 0.000 abstract description 4
- 239000006227 byproduct Substances 0.000 abstract description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 33
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 18
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 18
- 239000000243 solution Substances 0.000 description 18
- 235000019256 formaldehyde Nutrition 0.000 description 11
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 235000019253 formic acid Nutrition 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000010865 sewage Substances 0.000 description 6
- 238000005086 pumping Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- BGJSXRVXTHVRSN-UHFFFAOYSA-N 1,3,5-trioxane Chemical group C1OCOCO1 BGJSXRVXTHVRSN-UHFFFAOYSA-N 0.000 description 3
- 239000012670 alkaline solution Substances 0.000 description 3
- 238000002306 biochemical method Methods 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000004065 wastewater treatment Methods 0.000 description 3
- 241000894006 Bacteria Species 0.000 description 2
- 229910010413 TiO 2 Inorganic materials 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- SOAGOCJXMJUWQY-UHFFFAOYSA-N [O-2].[Ti+4].[Cu]=O.[O-2] Chemical compound [O-2].[Ti+4].[Cu]=O.[O-2] SOAGOCJXMJUWQY-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000011272 standard treatment Methods 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N zinc oxide Inorganic materials [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
- JRFBNCLFYLUNCE-UHFFFAOYSA-N zinc;oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[O-2].[Ti+4].[Zn+2] JRFBNCLFYLUNCE-UHFFFAOYSA-N 0.000 description 1
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Abstract
The utility model discloses a system for comprehensively treating polyoxymethylene wastewater, which comprises a polyoxymethylene wastewater raw water tank, a gas-liquid mixer, a heat exchanger, a fixed bed catalytic reactor, an oxidation completion liquid storage tank, an alkali liquid tank, a neutralization tank, a buffer tank, a first-effect evaporator and a second-effect evaporator which are sequentially connected, wherein the gas-liquid mixer is connected with an ozone generator, and the neutralization tank is connected with a pH on-line detector; the heat source medium inlet of the second-effect evaporator is connected with the first-effect evaporator feed liquid evaporation gas outlet, the second-effect evaporator feed liquid inlet is connected with the first-effect evaporator feed liquid outlet, the second-effect evaporator feed liquid evaporation gas outlet is connected with the waste water tank through the heat exchanger and the evaporation gas condenser, the second-effect evaporator heat source medium outlet is connected with the waste water tank through the evaporation gas condenser, and the second-effect evaporator feed liquid outlet is connected with the concentrated solution storage tank through the concentrated solution cooler. According to the utility model, the useful components in the polyoxymethylene wastewater are fully recycled, and the sodium formate solution product with the mass fraction of 20-30% is obtained as a byproduct, so that the resource waste is avoided to the greatest extent.
Description
Technical Field
The utility model relates to a wastewater treatment system, in particular to a system for comprehensively treating polyoxymethylene wastewater.
Background
The polyoxymethylene wastewater is wastewater with high COD, high salt and strong acidity generated in the production process of the polyoxymethylene device. Under the condition of stable production, the COD of the polyoxymethylene waste water is 8000-12000 mg/L, the pH is 2-3, the composition is complex, the water content is 96.5-97 wt%, the sodium formate is 1.1-1.3 wt%, the formic acid is 1.2-1.5 wt%, the formaldehyde is 600-800 ppm, and the polyoxymethylene waste water also contains a plurality of substances such as a trace amount of methanol, trioxymethylene, dioxypentacyclic and the like. Wherein the contribution rate of sodium formate, formic acid and formaldehyde with higher content to the total COD of the wastewater reaches more than 95 percent. Aiming at the treatment of the polyoxymethylene wastewater, a commonly adopted method in the industry is a biochemical method, but the wastewater has high COD, strong acidity and high formaldehyde concentration (when the formaldehyde concentration exceeds 200ppm, the growth and propagation of bacteria are seriously inhibited), and the tolerance limit of the bacteria is exceeded. Therefore, the pH of the polyoxymethylene wastewater needs to be adjusted by adding alkali, and the polyoxymethylene wastewater can enter a biochemical system through a large number of diluting methods, so that the total amount of wastewater to be treated is greatly increased, the wastewater treatment load of a sewage treatment plant is increased, and the treatment of other wastewater in a park is indirectly influenced. In addition, the biochemical method is used for treating the polyoxymethylene wastewater, and organic components with high added values in the polyoxymethylene wastewater are subjected to indiscriminate biochemical degradation, so that resource waste is caused to a certain extent.
Disclosure of utility model
The utility model aims to overcome the defects in the prior art and provides a system for comprehensively treating polyoxymethylene wastewater. The utility model carries out a series of treatments such as ozone catalytic oxidation, alkali solution neutralization, evaporation concentration and the like on condensed wastewater, converts and recycles useful components in the condensed wastewater to obtain a sodium formate acid solution product with high added value, and then subjects the residual wastewater with greatly reduced COD and formaldehyde concentration and weakened acidity to standard treatment by a wastewater treatment plant through a biochemical method.
The aim of the utility model is achieved by the following technical scheme.
The utility model relates to a system for comprehensively treating polyoxymethylene wastewater, which comprises a polyoxymethylene wastewater raw water tank, wherein a discharge port of the polyoxymethylene wastewater raw water tank is sequentially connected with a gas-liquid mixer, a heat exchanger, a fixed bed catalytic reactor, an oxidation completion liquid storage tank, a neutralization tank, a buffer tank and a one-effect evaporator through pipelines; the gas-liquid mixer is connected with an ozone generator through a pipeline, the neutralization tank is provided with a pH on-line detector, and a feed inlet of the neutralization tank is connected with a alkali liquid tank through a pipeline;
The heat source medium inlet of the two-effect evaporator is connected to the feed liquid evaporation gas outlet at the top of the one-effect evaporator through a pipeline, the feed liquid inlet of the two-effect evaporator is connected to the feed liquid outlet at the bottom of the one-effect evaporator through a pipeline, the feed liquid evaporation gas outlet at the top of the two-effect evaporator is connected to the wastewater tank through a heat exchanger and an evaporation gas condenser in sequence through a pipeline, the heat source medium outlet of the two-effect evaporator is connected to the wastewater tank through an evaporation gas condenser through a pipeline, and the concentrate outlet at the bottom of the two-effect evaporator is connected to the concentrate storage tank through a concentrate cooler through a pipeline.
The device is characterized in that a polyoxymethylene wastewater raw water pump is arranged on a pipeline connected between the polyoxymethylene wastewater raw water tank and the gas-liquid mixer, an oxidation completion liquid transfer pump is arranged on a pipeline connected between the oxidation completion liquid storage tank and the neutralization tank, an alkaline liquid pump is arranged on a pipeline connected between the alkaline liquid tank and the neutralization tank, a buffer tank feed pump is arranged on a pipeline connected between the neutralization tank and the buffer tank, an effective evaporator feed pump is arranged on a pipeline connected between the buffer tank and the first effective evaporator, a loading pump is arranged at a liquid outlet of the concentrate storage tank, and a wastewater transfer pump is arranged at a liquid outlet of the wastewater tank.
The heat exchanger is arranged into a shell-and-tube structure, a heat source passes through a shell pass, a material liquid passes through a tube pass, a material liquid inlet of the heat exchanger is connected to a liquid outlet of the gas-liquid mixer through a pipeline, a material liquid outlet of the heat exchanger is connected to a feed inlet of the fixed bed catalytic reactor through a pipeline, a heat source inlet of the heat exchanger is connected to a material liquid evaporation gas outlet at the top of the two-effect evaporator through a pipeline, and a heat source outlet of the heat exchanger is connected to an evaporation gas condenser through a pipeline.
The shell side inlet and the shell side outlet of the first-effect evaporator are respectively used as a heat source medium inlet and a heat source medium outlet, the tube side inlet, the top tube side outlet and the bottom tube side outlet of the first-effect evaporator are respectively used as a feed liquid inlet, a feed liquid evaporation gas outlet and a feed liquid outlet, the feed liquid inlet of the first-effect evaporator is connected with a feed pump of the first-effect evaporator through a pipeline, the feed liquid evaporation gas outlet at the top of the first-effect evaporator is connected to the heat source medium inlet of the second-effect evaporator through a pipeline, and the feed liquid outlet at the bottom of the first-effect evaporator is connected to the feed liquid inlet of the second-effect evaporator through a pipeline.
The double-effect evaporator is in a shell-and-tube structure, steam passes through a shell side, feed liquid passes through a tube side, a shell side inlet and a shell side outlet of the double-effect evaporator are respectively used as a heat source medium inlet and a heat source medium outlet, and a tube side inlet, a top tube side outlet and a bottom tube side outlet of the double-effect evaporator are respectively used as a feed liquid inlet, a feed liquid evaporation gas outlet and a concentrated liquid outlet.
The evaporator condenser is arranged to be of a shell-and-tube structure, an evaporation gas tube pass and a cooling medium tube pass, a tube pass inlet, a top tube pass outlet and a bottom tube pass outlet of the evaporator condenser are respectively used as an evaporation gas inlet, a non-condensable gas outlet and a condensate outlet, the evaporation gas inlet of the evaporator condenser is respectively connected to a heat source outlet of a heat exchanger and a heat source medium outlet of a two-effect evaporator through pipelines, the non-condensable gas outlet of the evaporator condenser is provided with a torch, and a condensate outlet of the evaporator condenser is connected to a wastewater tank through pipelines.
Compared with the prior art, the technical scheme of the utility model has the following beneficial effects:
(1) According to the utility model, the comprehensive treatment of the polyoxymethylene wastewater is realized, meanwhile, useful components in the polyoxymethylene wastewater are recycled as much as possible, and the byproduct sodium formate solution product with the mass fraction of 20-30% is obtained, so that the polyoxymethylene wastewater can be sold as a raw material of a single carbon source or a composite carbon source, the resource waste is avoided, the product structure of enterprises is enriched, and considerable economic benefits can be brought to the enterprises.
(2) The utility model oxidizes formaldehyde and methanol in the wastewater into formic acid, and generates sodium formate by reacting with the originally existing formic acid in the system and the added sodium hydroxide solution, thereby not only improving the content of sodium formate, but also reducing the pH value of the system. Then, the COD of the distilled liquid after the double-effect evaporation is reduced from 8000-12000 mg/L to below 1500mg/L, the pH is increased from 2-3 to 7-8, the formaldehyde content is reduced from 600-800 ppm to below 100ppm, and the distilled liquid is treated by a sewage treatment plant, so that the inhibition of formaldehyde on microorganisms is avoided, water is not required to be added for dilution, the biochemical treatment can be realized without adjusting the pH, the water is saved, the total amount of wastewater to be treated is greatly reduced, the treatment load of the sewage treatment plant is reduced, and the medicament cost is also saved. In addition, the total COD is reduced, so that the difficulty of biochemical treatment can be reduced, and the treatment time can be shortened.
Drawings
FIG. 1 is a schematic diagram of a system for comprehensive treatment of polyoxymethylene wastewater of the present utility model.
Reference numerals: 1-polyoxymethylene wastewater raw water tank, 2-polyoxymethylene wastewater raw water pump, 3-gas-liquid mixer, 4-ozone generator, 5-heat exchanger, 6-fixed bed catalytic reactor, 7-oxidation completion liquid storage tank, 8-oxidation completion liquid transfer pump, 9-alkali liquid tank, 10-alkali liquid pump, 11-neutralization tank, 12-pH on-line detector, 13-buffer tank feed pump, 14-buffer tank, 15-first-effect evaporator feed pump, 16-first-effect evaporator, 17-second-effect evaporator, 18-concentrate cooler, 19-concentrate storage tank, 20-loading pump, 21-evaporating gas condenser, 22-wastewater tank, 23-wastewater transfer pump.
Detailed Description
The utility model is further described below with reference to the accompanying drawings.
As shown in fig. 1, the system for comprehensively treating the polyoxymethylene wastewater mainly comprises a polyoxymethylene wastewater raw water tank 1, a polyoxymethylene wastewater raw water pump 2, a gas-liquid mixer 3, an ozone generator 4, a heat exchanger 5, a fixed bed catalytic reactor 6, an oxidation completion liquid storage tank 7, an oxidation completion liquid transfer pump 8, an alkali liquid tank 9, an alkali liquid pump 10, a neutralization tank 11, a pH on-line detector 12, a buffer tank feed pump 13, a buffer tank 14, a first-effect evaporator feed pump 15, a first-effect evaporator 16, a second-effect evaporator 17, a concentrate cooler 18, a concentrate storage tank 19, a loading pump 20, an evaporation gas condenser 21, a wastewater tank 22, a wastewater transfer pump 23 and related connecting pipelines.
The discharge port of the polyoxymethylene wastewater raw water tank 1 is sequentially connected with a gas-liquid mixer 3, a heat exchanger 5, a fixed bed catalytic reactor 6, an oxidation completion liquid storage tank 7, a neutralization tank 11, a buffer tank 14 and a first-effect evaporator 16 through pipelines. The gas-liquid mixer 3 is connected with an ozone generator 4 through a pipeline, the neutralization tank 11 is provided with a pH on-line detector 12, and a feed inlet of the neutralization tank 11 is connected with an alkali liquor tank 9 through a pipeline. The heat source medium inlet of the two-effect evaporator 17 is connected to the feed liquid evaporation gas outlet at the top of the one-effect evaporator 16 through a pipeline, the feed liquid inlet of the two-effect evaporator 17 is connected to the feed liquid outlet at the bottom of the one-effect evaporator 16 through a pipeline, the feed liquid evaporation gas outlet at the top of the two-effect evaporator 17 is connected to the wastewater tank 22 through a pipeline sequentially through the heat exchanger 5 and the evaporation gas condenser 21, the heat source medium outlet of the two-effect evaporator 17 is connected to the wastewater tank 22 through a pipeline through the evaporation gas condenser 21, and the concentrate outlet at the bottom of the two-effect evaporator 17 is connected to the concentrate storage tank 19 through a pipeline through the concentrate cooler 18.
In the system, a polyoxymethylene wastewater raw water pump 2 is arranged on a pipeline connected between the polyoxymethylene wastewater raw water tank 1 and the gas-liquid mixer 3, an oxidation completion liquid transfer pump 8 is arranged on a pipeline connected between the oxidation completion liquid storage tank 7 and the neutralization tank 11, an alkaline liquid pump 10 is arranged on a pipeline connected between the alkaline liquid tank 9 and the neutralization tank 11, a buffer tank feed pump 13 is arranged on a pipeline connected between the neutralization tank 11 and the buffer tank 14, and an effective evaporator feed pump 15 is arranged on a pipeline connected between the buffer tank 14 and the effective evaporator 16. The liquid outlet of the concentrated solution storage tank 19 is provided with a loading pump 20, and the sodium formate solution in the concentrated solution storage tank 19 can be used as a raw material of a single carbon source or a composite carbon source and sold after being loaded by the loading pump 20. The liquid outlet of the wastewater tank 22 is provided with a wastewater transfer pump 23, and wastewater in the wastewater tank 22 is sent to a sewage treatment plant through the wastewater transfer pump 23 and discharged after reaching standards.
In the above system, the heat exchanger 5 is configured as a shell-and-tube structure, the heat source passes through the shell side, and the feed liquid passes through the tube side. The feed liquid inlet of the heat exchanger 5 is connected to the liquid outlet of the gas-liquid mixer 3 through a pipeline, the feed liquid outlet of the heat exchanger 5 is connected to the feed inlet of the fixed bed catalytic reactor 6 through a pipeline, the heat source inlet of the heat exchanger 5 is connected to the feed liquid evaporation gas outlet at the top of the double-effect evaporator 17 through a pipeline, and the heat source outlet of the heat exchanger 5 is connected to the evaporation gas condenser 21 through a pipeline. Meanwhile, a first steam pipeline for use in the driving stage is further connected to the heat source inlet of the heat exchanger 5, and a first steam condensate pipeline for use in the driving stage is further connected to the heat source outlet of the heat exchanger 5. The steam used can be low-pressure steam of the existing production system, the gauge pressure is 0.2-0.3 MPa, and the temperature is 140-160 ℃. In the starting stage, when no material is generated at the top of the two-effect evaporator 17, the steam conveyed by the first steam pipeline can be used for preheating the feed in the heat exchanger 5; when the flow is completed and the feed liquid evaporation gas is generated at the top of the two-effect evaporator 17, the heat exchanger 5 can stop the steam conveyed by the first steam pipeline as a heat source, switch to the normal heat exchange flow and use the evaporation gas at the top of the two-effect evaporator 17 as the heat source. In addition, in order to satisfy the above-mentioned switching process, valves may be provided on the pipes connecting the heat source inlet and the heat source outlet of the heat exchanger 5.
In the above system, the first-effect evaporator 16 is configured as a shell-and-tube structure, and the steam passes through the shell side and the feed liquid passes through the tube side. The shell side inlet and the shell side outlet of the first-effect evaporator 16 are respectively used as a heat source medium inlet and a heat source medium outlet, and are respectively connected with a second steam pipeline and a second steam condensate pipeline. The tube side inlet, the top tube side outlet and the bottom tube side outlet of the first-effect evaporator 16 are respectively used as a feed liquid inlet, a feed liquid evaporation gas outlet and a feed liquid outlet, the feed liquid inlet of the first-effect evaporator 16 is connected with the first-effect evaporator feed pump 15 through a pipeline, the feed liquid evaporation gas outlet at the top of the first-effect evaporator 16 is connected to the heat source medium inlet of the second-effect evaporator 17 through a pipeline, and the feed liquid outlet at the bottom of the first-effect evaporator 16 is connected to the feed liquid inlet of the second-effect evaporator 17 through a pipeline.
In the above system, the two-effect evaporator 17 is configured as a shell-and-tube structure, the steam passes through a shell side, the feed liquid passes through a tube side, the shell side inlet and the shell side outlet of the two-effect evaporator 17 are respectively used as a heat source medium inlet and a heat source medium outlet, the tube side inlet, the top tube side outlet and the bottom tube side outlet of the two-effect evaporator 17 are respectively used as a feed liquid inlet, a feed liquid evaporation gas outlet and a concentrate outlet, and the concentrate outlet at the bottom of the two-effect evaporator 17 is connected to the concentrate storage tank 19 through a concentrate cooler 18 by pipelines.
In the above system, the evaporator condenser 21 is configured as a shell-and-tube structure, the evaporation gas passes through a tube side, the cooling medium passes through a shell side, the tube side inlet, the top tube side outlet and the bottom tube side outlet of the evaporator condenser 21 are respectively used as an evaporation gas inlet, a non-condensable gas outlet and a condensate outlet, the evaporation gas inlet of the evaporator condenser 21 is respectively connected to the heat source outlet of the heat exchanger 5 and the heat source medium outlet of the two-effect evaporator 17 through pipelines, the non-condensable gas outlet of the evaporator condenser 21 is provided with a torch, the non-condensable gas generated in the evaporator condenser 21 is discharged through the non-condensable gas outlet, and the condensate outlet of the evaporator condenser 21 is connected to the wastewater tank 22 through pipelines.
In the above system, the concentrate cooler 18 and the boil-off gas condenser 21 may each use cooling water as a cooling medium.
In the above system, the steam used by the first-effect evaporator 16 (conveyed by the second steam pipeline) can be derived from low-pressure steam of the existing production system on site, the gauge pressure is 0.6-0.8 MPa, the temperature is 220-280 ℃, the steam condensate is recycled to the production system, the steam generated at the top of the first-effect evaporator 16 is used as secondary steam to provide a heat source for the second-effect evaporator 17, the non-evaporated feed liquid at the bottom of the first-effect evaporator 16 enters the second-effect evaporator 17 for further evaporation and concentration, and the steam generated at the top of the second-effect evaporator 17 is conveyed to the heat exchanger 5 to be used as a heat source to preheat the feed of the heat exchanger 5.
The treatment process of the system based on the comprehensive treatment of the polyoxymethylene wastewater is as follows:
The first step: starting a polyoxymethylene wastewater raw water pump 2, and pumping the polyoxymethylene wastewater in the polyoxymethylene wastewater raw water tank 1 into a gas-liquid mixer 3 according to the flow rate of 80-100 m 3/h. Simultaneously, the ozone generator 4 is started, ozone is introduced into the gas-liquid mixer 3, so that the ozone and the polyoxymethylene wastewater are fully mixed in the gas-liquid mixer 3, and the concentration of the ozone in the mixed feed liquid is controlled at 300-500 ppm. The mixed feed liquid enters a heat exchanger 5, is preheated to 50-70 ℃ and then enters a fixed bed catalytic reactor 6, formaldehyde and methanol in the feed liquid are oxidized into formic acid by ozone under the action of a catalyst, the total content of formic acid in a feed liquid system is improved, and the oxidized feed liquid flows into an oxidation completion liquid storage tank 7 for standby.
Wherein, the COD of the raw water of the polyoxymethylene waste water is 8000-12000 mg/L, the pH is 2-3, the water content is 96.5-97 wt%, the sodium formate is 1.1-1.3 wt%, the formic acid is 1.2-1.5 wt%, the formaldehyde is 600-800 ppm, and the polyoxymethylene waste water contains a plurality of substances such as micro methanol, trioxymethylene, dioxypentacyclic and the like. The space velocity of the fixed bed catalytic reactor 6 is 15-25 h -1, and the catalyst used is TiO 2 -ZnO (titanium dioxide-zinc oxide) or TiO 2 -CuO (titanium dioxide-copper oxide).
And a second step of: starting an oxidation completion liquid transfer pump 8, and pumping the feed liquid in the oxidation completion liquid storage tank 7 to a 50-60% liquid level position of the neutralization tank 11. Starting an alkaline solution pump 10, pumping 40-50 wt.% sodium hydroxide solution in an alkaline solution tank 9 into a neutralization tank 11, and carrying out neutralization reaction on the sodium hydroxide and formic acid in the feed liquid to completely convert the formic acid into sodium formate so as to improve the sodium formate content in the system. When the pH value detected by the pH on-line detector 12 shows that the pH value is 7-8, the alkaline solution pump 10 is stopped, and the alkali solution is stopped from being added into the neutralization tank 11. And starting a buffer tank feeding pump 13, and pumping the neutralized feed liquid into a buffer tank 14 for standby.
And a third step of: the feeding pump 15 of the first-effect evaporator is started, the feed liquid in the buffer tank 14 is pumped to the first-effect evaporator 16 for one-time evaporation, and part of water and unoxidized light components such as formaldehyde, methanol and the like in the wastewater are distilled out. The vaporized gas enters the two-effect evaporator 17 as secondary vapor from the top of the one-effect evaporator 16 to provide a heat source for it. The feed liquid which is not evaporated at the bottom of the first-effect evaporator 16 flows into the second-effect evaporator 17 to be evaporated and concentrated continuously, and part of water and residual light components such as formaldehyde, methanol and the like are further evaporated. The gas evaporated from the top of the two-effect evaporator 17 passes through the heat exchanger 5 and then is converged with the secondary steam condensate of the two-effect evaporator 17 to enter the evaporation gas condenser 21, and the evaporation gas is cooled to 30-40 ℃ and then enters the wastewater tank 22, so that the non-condensable gas is removed from the torch. The main components of the concentrated solution at the bottom of the two-effect evaporator 17 are sodium formate, water, trace amount of trioxymethylene, dioxypentacyclic and the like, and the concentrated solution is cooled to 20-30 ℃ by a concentrated solution cooler 18 and enters a concentrated solution storage tank 19.
Wherein, in the starting stage, when no material is generated at the top of the two-effect evaporator 17, the steam provided by the first steam pipeline can be used for preheating the feed in the preheater 5; when the flow is completed and the feed liquid evaporation gas is generated at the top of the two-effect evaporator 17, the heat exchanger 5 can stop the steam provided by the first steam pipeline as a heat source, switch to the normal heat exchange flow and use the evaporation gas at the top of the two-effect evaporator 17 as the heat source.
Wherein, the heat source used by the first-effect evaporator 16 is from the low-pressure steam of the existing production system on site, the pressure is 0.6-0.8 MPa, the temperature is 220-280 ℃, and the steam condensate returns to the system. The operating pressure of the first-effect evaporator 16 is 0.03-0.05 MPa, and the operating pressure of the second-effect evaporator 17 is-0.01 MPa. The feeding flow of the first-effect evaporator 16 is 80-100 t/h, the evaporation capacity (namely, the secondary steam flow) of the feed liquid evaporation gas of the first-effect evaporator 16 is 48-60 t/h, the evaporation capacity (namely, the steam flow produced at the top of the second-effect evaporator 10) of the feed liquid evaporation gas of the second-effect evaporator 17 is 24-30 t/h, the flow of the concentrated solution is 8-10 t/h, and the mass fraction of sodium formate in the concentrated solution is 20-30%. The medium pressure is measured by a gauge pressure meter.
Fourth step: starting a waste water transfer pump 23, pumping the residual waste water (COD is less than 1500mg/L, formaldehyde concentration is less than 100ppm, pH is 7-8) in the waste water tank 22 to a sewage treatment plant for continuous biochemical treatment, and discharging after reaching the standard. Wherein the flow rate of the waste water transfer pump 23 is 72-90 t/h.
Fifth step: and starting the loading pump 20, and taking the sodium formate solution in the concentrated solution storage tank 19 as a raw material of a single carbon source or a composite carbon source for loading and selling.
According to the utility model, the useful components in the polyoxymethylene wastewater are fully recycled, and the byproduct is obtained as a sodium formate solution product with high added value, so that the resource waste is avoided to the greatest extent, the product structure of enterprises is enriched, considerable economic benefits are brought to the enterprises, the residual wastewater enters a sewage treatment plant to be directly biochemically treated without being diluted by adding water, the water is saved, the medicament cost for adjusting the pH is saved, the treatment difficulty is reduced, and the treatment time is shortened.
Although the function and operation of the present utility model has been described above with reference to the accompanying drawings, the present utility model is not limited to the above-described specific functions and operations, but the above-described specific embodiments are merely illustrative, not restrictive, and many forms can be made by those having ordinary skill in the art without departing from the spirit of the present utility model and the scope of the appended claims, which are included in the protection of the present utility model.
Claims (6)
1. The system for comprehensively treating the polyoxymethylene wastewater comprises a polyoxymethylene wastewater raw water tank (1), and is characterized in that a discharge port of the polyoxymethylene wastewater raw water tank (1) is sequentially connected with a gas-liquid mixer (3), a heat exchanger (5), a fixed bed catalytic reactor (6), an oxidation completion liquid storage tank (7), a neutralization tank (11), a buffer tank (14), a first-effect evaporator (16) and a second-effect evaporator (17) through pipelines; the gas-liquid mixer (3) is connected with an ozone generator (4) through a pipeline, the neutralization tank (11) is provided with a pH on-line detector (12), and the feed inlet of the neutralization tank (11) is connected with an alkali liquor tank (9) through a pipeline;
The heat source medium inlet of the two-effect evaporator (17) is connected to the feed liquid evaporation gas outlet at the top of the one-effect evaporator (16) through a pipeline, the feed liquid inlet of the two-effect evaporator (17) is connected to the feed liquid outlet at the bottom of the one-effect evaporator (16) through a pipeline, the feed liquid evaporation gas outlet at the top of the two-effect evaporator (17) is connected to the wastewater tank (22) through a pipeline sequentially through the heat exchanger (5) and the evaporation gas condenser (21), the heat source medium outlet of the two-effect evaporator (17) is connected to the wastewater tank (22) through the evaporation gas condenser (21) through a pipeline, and the concentrate outlet at the bottom of the two-effect evaporator (17) is connected to the concentrate storage tank (19) through a concentrate cooler (18) through a pipeline.
2. The system for comprehensively treating the polyoxymethylene wastewater according to claim 1, wherein a polyoxymethylene wastewater raw water pump (2) is arranged on a pipeline connected between a polyoxymethylene wastewater raw water tank (1) and a gas-liquid mixer (3), an oxidation completion liquid transfer pump (8) is arranged on a pipeline connected between an oxidation completion liquid storage tank (7) and a neutralization tank (11), an alkaline liquid pump (10) is arranged on a pipeline connected between an alkaline liquid tank (9) and the neutralization tank (11), a buffer tank feed pump (13) is arranged on a pipeline connected between the neutralization tank (11) and a buffer tank (14), an effective evaporator feed pump (15) is arranged on a pipeline connected between the buffer tank (14) and an effective evaporator (16), a loading pump (20) is arranged at a liquid outlet of the concentrate storage tank (19), and a wastewater transfer pump (23) is arranged at a liquid outlet of the wastewater tank (22).
3. The system for comprehensively treating the polyoxymethylene wastewater according to claim 1, wherein the heat exchanger (5) is arranged in a shell-and-tube structure, a heat source is arranged in a shell-and-tube side, a liquid inlet of the heat exchanger (5) is connected to a liquid outlet of the gas-liquid mixer (3) through a pipeline, a liquid outlet of the heat exchanger (5) is connected to a feed inlet of the fixed bed catalytic reactor (6) through a pipeline, a heat source inlet of the heat exchanger (5) is connected to a liquid evaporation gas outlet at the top of the two-effect evaporator (17) through a pipeline, and a heat source outlet of the heat exchanger (5) is connected to an evaporation gas condenser (21) through a pipeline.
4. The system for comprehensively treating the polyoxymethylene wastewater according to claim 1, wherein the first-effect evaporator (16) is arranged in a shell-and-tube structure, steam is sent to a shell side, feed liquid is sent to a tube side, a shell side inlet and a shell side outlet of the first-effect evaporator (16) are respectively used as a heat source medium inlet and a heat source medium outlet, a tube side inlet, a top tube side outlet and a bottom tube side outlet of the first-effect evaporator (16) are respectively used as a feed liquid inlet, a feed liquid evaporation gas outlet and a feed liquid outlet, the feed liquid inlet of the first-effect evaporator (16) is connected with a first-effect evaporator feed pump (15) through a pipeline, the feed liquid evaporation gas outlet at the top of the first-effect evaporator (16) is connected to the heat source medium inlet of the second-effect evaporator (17) through a pipeline, and the feed liquid outlet at the bottom of the first-effect evaporator (16) is connected to the feed liquid inlet of the second-effect evaporator (17) through a pipeline.
5. The system for comprehensively treating the polyoxymethylene wastewater according to claim 1, wherein the two-effect evaporator (17) is arranged in a shell-and-tube structure, steam is sent to a shell side, feed liquid is sent to a tube side, a shell side inlet and a shell side outlet of the two-effect evaporator (17) are respectively used as a heat source medium inlet and a heat source medium outlet, and a tube side inlet, a top tube side outlet and a bottom tube side outlet of the two-effect evaporator (17) are respectively used as a feed liquid inlet, a feed liquid evaporation gas outlet and a concentrated liquid outlet.
6. The system for comprehensively treating the polyoxymethylene wastewater according to claim 1, wherein the evaporation gas condenser (21) is provided with a shell-and-tube structure, an evaporation gas tube pass is carried out, a cooling medium is carried out, a tube pass inlet, a top tube pass outlet and a bottom tube pass outlet of the evaporation gas condenser (21) are respectively used as an evaporation gas inlet, a non-condensable gas outlet and a condensate outlet, the evaporation gas inlet of the evaporation gas condenser (21) is respectively connected to a heat source outlet of the heat exchanger (5) and a heat source medium outlet of the two-effect evaporator (17) through pipelines, a non-condensable gas outlet of the evaporation gas condenser (21) is provided with a torch, and the condensate outlet of the evaporation gas condenser (21) is connected to the wastewater tank (22) through pipelines.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322348404.7U CN221141493U (en) | 2023-08-29 | 2023-08-29 | System for comprehensive treatment of polyoxymethylene wastewater |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322348404.7U CN221141493U (en) | 2023-08-29 | 2023-08-29 | System for comprehensive treatment of polyoxymethylene wastewater |
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| CN221141493U true CN221141493U (en) | 2024-06-14 |
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| CN202322348404.7U Active CN221141493U (en) | 2023-08-29 | 2023-08-29 | System for comprehensive treatment of polyoxymethylene wastewater |
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| Country | Link |
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| CN (1) | CN221141493U (en) |
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2023
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