CN212655617U - PTA oxidation tail gas treatment and recovery system - Google Patents
PTA oxidation tail gas treatment and recovery system Download PDFInfo
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- CN212655617U CN212655617U CN202020961035.2U CN202020961035U CN212655617U CN 212655617 U CN212655617 U CN 212655617U CN 202020961035 U CN202020961035 U CN 202020961035U CN 212655617 U CN212655617 U CN 212655617U
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Abstract
The utility model discloses a PTA oxidation tail gas treatment and recovery system, this system includes: the washing device is communicated with the PTA oxidation tail gas discharge port; a filtering device communicated with the washing device; the primary nanofiltration device is communicated with the filtering device; the reverse osmosis device is communicated with the primary nanofiltration device; the steam decarbonization device is communicated with the reverse osmosis device; the secondary nanofiltration device is communicated with the steam decarbonization device; and the evaporation device is communicated with the secondary nanofiltration device. The utility model achieves the purpose of wastewater treatment by combining different membrane treatment technologies and evaporation technologies and matching with a hot decarburization technology; a reverse osmosis device is adopted to recover the wastewater and reduce the supplement amount of the fresh washing water; the nanofiltration device and the steam decarbonization tower are adopted, carbonate in the recovered water is used for washing the tail gas of the washing tower, the solid alkali addition is reduced, and the purpose of reducing alkali consumption is achieved; the bromine salt with higher economic value can be recovered by adopting an evaporation device, thereby achieving the purpose of resource utilization.
Description
Technical Field
The utility model relates to a PTA waste water resourceization, saving technology technical field especially relate to a PTA oxidation tail gas processing and recovery system.
Background
Since the 80's of the 20 th century, the market demand for PTA (terephthalic acid) has increased dramatically, resulting in a rapid increase in PTA productivity, which has also driven the development of PTA wastewater treatment technologies. At present, PTA is generally prepared by catalytic oxidation of Paraxylene (PX) at high temperature and high pressure, and then refining. In the tail gas treatment process, the tail gas can generate part of washing wastewater after being washed by the washing tower, wherein the washing wastewater contains bromide ions with certain concentration, so that the washing wastewater has higher economic value, and if the washing wastewater is directly discharged, not only is the resource waste caused, but also the environmental pollution is caused.
Because the main components of the tail gas are nitrogen, carbon dioxide, carbon monoxide and brominated organic matters, after the washing tower is used for washing and debrominating, the main components of the washing wastewater are bicarbonate ions, carbonate ions and bromide ions, and a small amount of acetate, formate and the like, the COD content is lower, and if the washing wastewater is directly mixed into other wastewater, the bromide ions in the sewage not only can increase the biochemical influence, but also increase the load of biochemical treatment, and the process and the feasibility are unreasonable.
At present, various PTA oxidation tail gas purification technologies, such as an adsorption method, a condensation method, a direct combustion method and the like, have been reported, and the methods can generate secondary pollution, have high energy consumption, and have purification effects easily limited by the concentration and temperature of organic waste gas. The patent application with the application number of 201711415474.2 discloses a PTA oxidized tail gas purification and bromine recovery device and a process, the method adopts a method of catalytic heat storage type reactor + alkali liquor washing + hydrogen peroxide or chlorine reduction to treat tail gas, the method has the problems that reducing agents such as hydrogen peroxide or chlorine are required to be added, certain safety risks exist no matter hydrogen peroxide or chlorine reduction, and strict requirements are imposed on the use working condition, management and the like of hydrogen peroxide or chlorine, so that the use comprehensiveness of the method is limited.
Therefore, it is an urgent need in the art to design a reasonable, simple and efficient treatment process.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a main aim at provides a PTA oxidation tail gas treatment and recovery system, this system and technology can avoid current processing technology to need the defect that adopts the reductant, and simultaneously, this system and technology have reduced technology operation risk, and the product is direct bromine salt or the solid for high concentration, has higher added value, has reduced the treatment cost.
In order to achieve the above object, the utility model provides a PTA oxidation tail gas treatment and recovery system, include:
the washing device is communicated with the PTA oxidation tail gas discharge port;
a filtering device communicated with the washing device;
the primary nanofiltration device is communicated with the filtering device;
the reverse osmosis device is communicated with the primary nanofiltration device;
the steam decarbonization device is communicated with the reverse osmosis device;
the secondary nanofiltration device is communicated with the steam decarbonization device; and
and the evaporation device is communicated with the secondary nanofiltration device.
PTA oxidation tail gas processing and recovery system, wherein, filter equipment is manganese sand filter equipment, filter equipment includes filtrating entry and filtrating export, filtrating entry with washing device's washing liquid export intercommunication, filtrating export with the one-level is received and is strained device intercommunication.
PTA oxidation tail gas handle and recovery system, wherein, the one-level is received the device and is received filtrating entry, one-level including the one-level and is received fresh water export and one-level and receive and strain the dense water export, the one-level receive the filtrating entry with filtrating export intercommunication, the one-level receive and strain fresh water export with reverse osmosis unit intercommunication, the one-level is received and is strained external biochemical treatment system of dense water exit linkage.
PTA oxidation tail gas processing and recovery system, wherein, reverse osmosis unit includes reverse osmosis fresh water export and the dense water export of reverse osmosis, reverse osmosis fresh water export with filter equipment's recoil liquid entry and/or washing device's washing liquid entry intercommunication, the dense water export of reverse osmosis with steam decarbonization device intercommunication.
PTA oxidation tail gas processing and recovery system, wherein, steam decarbonization device includes gas outlet and liquid outlet, gas outlet and external intercommunication, liquid outlet with the second grade is received and is strained device intercommunication.
PTA oxidation tail gas processing and recovery system, wherein, the second grade is received and is strained the device and is included that the second grade is received and strain fresh water export and the concentrated water export of second grade nanofiltration, evaporation plant includes evaporating liquid entry, evaporating liquid export and comdenstion water export, the second grade receive and strain fresh water export with evaporating liquid entry intercommunication, the second grade receive and strain the concentrated water export with the comdenstion water export respectively with washing device's washing liquid entry intercommunication.
The PTA oxidation tail gas treatment and recovery system of the utility model comprises a flash evaporation device communicated with the liquid outlet of the steam decarbonization device, the flash evaporation device comprises a steam outlet and a flash evaporation liquid outlet, and the steam outlet is communicated with the steam decarbonization device; and/or the pH value adjusting device is communicated with a flash liquid outlet of the flash evaporation device.
The PTA oxidation tail gas treatment and recovery system further comprises a pH value adjusting device which is communicated with a liquid outlet of the steam decarburization device.
The PTA oxidation tail gas treatment and recovery system comprises a PTA oxidation tail gas inlet, a PTA oxidation tail gas outlet and a washing liquid inlet, wherein the PTA oxidation tail gas inlet is communicated with a PTA oxidation tail gas outlet.
The utility model also provides a PTA oxidation tail gas treatment and recovery method, include:
step 1, washing PTA oxidized tail gas, and filtering the obtained washing liquid;
step 2, carrying out primary nanofiltration treatment on the filtrate obtained in the step 1 to obtain primary nanofiltration fresh water;
step 3, performing reverse osmosis treatment on the primary nanofiltration fresh water to obtain reverse osmosis concentrated water;
step 4, carrying out steam decarburization treatment on the reverse osmosis concentrated water;
step 5, carrying out secondary nanofiltration treatment on the liquid obtained in the step 4 to obtain secondary nanofiltration fresh water; and
and 6, evaporating the secondary nanofiltration fresh water to recover bromine salt.
The PTA oxidation tail gas treatment and recovery method of the utility model, wherein, after the steam decarburization treatment, the method also comprises the step of flash evaporation treatment of the liquid obtained by the steam decarburization treatment; and recycling the steam obtained after the flash evaporation treatment to the steam decarburization treatment process.
The PTA oxidation tail gas treatment and recovery method of the utility model, wherein, after the steam decarburization treatment or the flash evaporation treatment, the method also comprises the step of adding alkali liquor to adjust the pH value of the liquid.
The utility model discloses a PTA oxidation tail gas treatment and recovery method, wherein, the filtration of step 1 is carried out in a manganese sand filter device to remove suspended matters; and the first-stage nanofiltration treatment also obtains first-stage nanofiltration concentrated water, wherein the first-stage nanofiltration concentrated water comprises 30-50% of carbonate in the filtrate.
The PTA oxidation tail gas treatment and recovery method of the utility model, wherein, the ion concentration of the reverse osmosis concentrated water is 3-6 times of the ion concentration of the first-stage nanofiltration fresh water, the reverse osmosis treatment still obtains the reverse osmosis fresh water, the quality of the reverse osmosis fresh water accounts for 40% -70% of the quality of the first-stage nanofiltration fresh water; the reverse osmosis fresh water is used in the step 1 washing step and/or in the step 1 filtering step.
PTA oxidation tail gas processing and recovery method, wherein, the steam decarbonization processing is right reverse osmosis dense water carries out flash distillation strip decarbonization to make HCO3 -Thermal decomposition to CO3 2-And CO2The flash evaporation temperature is 100-180 ℃; the secondary nanofiltration treatment also obtains secondary nanofiltration concentrated water, and the mass of the secondary nanofiltration concentrated water accounts for 10 to 30 percent of the mass of the liquid obtained in the step 4; the secondary nanofiltration concentrated water is used for the washing step in the step 1.
The utility model discloses a PTA oxidation tail gas processing and recovery method, wherein, the evaporation treatment is direct evaporation, multiple-effect evaporation or MVR evaporation to improve the concentration of bromine salt in the obtained evaporation liquid; the condensed water obtained by the evaporation treatment is used in the washing step of step 1.
The utility model has the advantages that:
the utility model adopts the reverse osmosis process, recovers the reverse osmosis fresh water for the filtering process and the washing process, reduces the consumption of the fresh water and further achieves the purpose of water saving;
the utility model adopts the steam decarbonization process and the secondary nanofiltration process to recover the carbonate in the PTA oxidation tail gas washing water for washing the PTA oxidation tail gas in the washing process, thereby reducing the solid alkali dosage and further achieving the purpose of reducing the alkali consumption;
the utility model discloses the defect that current treatment process need adopt the reductant not only can be avoided through organic combination to the technology, can obtain the bromine salt solution or the bromine salt solid of high concentration high-efficiently moreover, improves the product added value, reaches resource utilization's purpose.
Drawings
FIG. 1 is a schematic view of a PTA oxidation tail gas treatment and recovery system in accordance with a first embodiment of the present invention;
FIG. 2 is a schematic view of a PTA oxidation tail gas treatment and recovery system in accordance with a second embodiment of the present invention;
fig. 3 is a schematic view of a PTA oxidation tail gas treatment and recovery system according to a third embodiment of the present invention.
Wherein, the reference numbers:
1 washing device
11 washing liquid inlet
12 outlet for washing liquid
13 PTA oxidation tail gas inlet
2 Filter device
21 filtrate inlet
22 filtrate outlet
23 backwash inlet
24 outlet of backflushing liquid
3 one-stage nanofiltration device
31 first-stage sodium filtrate inlet
32 first-stage nanofiltration fresh water outlet
33 first-stage nanofiltration concentrated water outlet
4 reverse osmosis device
41 reverse osmosis inlet
42 reverse osmosis concentrated water outlet
43 reverse osmosis fresh water outlet
5 steam decarbonization device
51 liquid inlet
52 liquid outlet
53 gas outlet
6 two-stage nanofiltration device
61 second-stage nanofiltration liquid inlet
62 two-stage nanofiltration fresh water outlet
63 two-stage nanofiltration concentrated water outlet
7 evaporating device
71 inlet of evaporated liquid
72 outlet for evaporated liquid
73 condensed water outlet
8 pH value adjusting device
81 liquid inlet
82 liquid outlet
83 acid and alkali liquor inlet
9 flash evaporation device
91 flash liquid inlet
92 flash liquid outlet
93 steam outlet
Detailed Description
The following embodiments of the present invention will be described in detail, and the following embodiments are implemented on the premise of the present invention, and detailed embodiments and processes are given, but the scope of the present invention is not limited to the following embodiments.
The utility model provides a PTA oxidation tail gas is handled and recovery system, as shown in fig. 1, fig. 1 is the utility model discloses PTA oxidation tail gas of first embodiment is handled and recovery system schematic diagram, and this system includes washing device 1, filter equipment 2, one-level nanofiltration device 3, reverse osmosis unit 4, steam decarbonization device 5, second grade nanofiltration device 6 and evaporation plant 7. Wherein, the washing device 1, the filtering device 2, the primary nanofiltration device 3, the reverse osmosis device 4, the steam decarbonization device 5, the secondary nanofiltration device 6 and the evaporation device 7 are connected in sequence; a filtering device 2 communicating with the washing device 1; the primary nanofiltration device 3 is communicated with the filtration device 2; the reverse osmosis device 4 is communicated with the primary nanofiltration device 3; the steam decarbonization device 5 is communicated with the reverse osmosis device 4; the secondary nanofiltration device 6 is communicated with the steam decarbonization device 5; and an evaporation device 7 communicated with the secondary nanofiltration device 6. In addition, the washing apparatus 1 communicates with a PTA oxidation off-gas discharge port.
In one embodiment, the scrubber 1 is, for example, a scrubber tower. The washing device 1 comprises a washing liquid inlet 11, a washing liquid outlet 12, a PTA oxidation tail gas inlet 13 and a PTA oxidation tail gas outlet 14. The PTA oxidized tail gas discharged from the oxidized tail gas discharge port of the PTA reactor (not shown) enters the washing apparatus 1 from the PTA oxidized tail gas inlet 13, is contacted and washed with the washing liquid entering from the washing liquid inlet 11, and the washed oxidized tail gas is discharged from the washing apparatus 1 from the PTA oxidized tail gas outlet 14. After the washing liquid is contacted and washed with the oxidized tail gas, the washing liquid contains bicarbonate ions, carbonate ions and bromide ions with certain concentration and is discharged out of the washing device 1 from a washing liquid outlet 12.
In an embodiment, the filtration device 2 comprises a filtrate inlet 21 and a filtrate outlet 22. The filtrate inlet 21 is communicated with the washing liquid outlet 12 of the washing device 1, so that the washing liquid in the washing device 1 enters the filtering device 2 through the filtrate inlet 21 for filtering; the filtered filtrate exits the filter device 2 through the filtrate outlet 22. In one embodiment, the filter device 2 is a manganese sand filter device. The washing liquid is filtered through a filter device 2 to remove suspended matter. After a certain period of operation of the filter device 2, a backwash treatment is required in order to ensure the filtering efficiency, and therefore in another embodiment the filter device 2 comprises a backwash inlet 23 and a backwash outlet 24. The recoil fresh water enters the filtering device 2 through the recoil liquid inlet 23, and is subjected to the backwashing operation, the wastewater generated after the backwashing is discharged out of the filtering device 2 through the recoil liquid outlet 24, and the wastewater can be discharged into the biochemical treatment device for treatment, but the utility model discloses do not use this as the limit.
In one embodiment, the primary nanofiltration device 3 comprises a primary nanofiltration filtrate inlet 31, a primary nanofiltration fresh water outlet 32 and a primary nanofiltration concentrated water outlet 33. The first-stage nanofiltration liquid inlet 31 is communicated with the filtrate outlet 22, so that the filtrate passing through the filtering device 2 enters the first-stage nanofiltration device 3 through the first-stage nanofiltration liquid inlet 31. According to the southward effect of the nanofiltration device on anions with different valence states, the filtrate is separated into primary nanofiltration fresh water and primary nanofiltration concentrated water after passing through the primary nanofiltration device 3, and the primary nanofiltration fresh water and the primary nanofiltration concentrated water are respectively discharged out of the primary nanofiltration device 3 from a primary nanofiltration fresh water outlet 32 and a primary nanofiltration concentrated water outlet 33. In one embodiment, the first-stage nanofiltration concentrated water outlet 33 is communicated with an external biochemical treatment system, so that the first-stage nanofiltration concentrated water is discharged from the first-stage nanofiltration concentrated water outlet 33 and then enters the biochemical treatment system for further treatment. In one embodiment, the first nanofiltration concentrate comprises 30% to 50% of carbonate in the filtrate, i.e. the first nanofiltration concentrate comprises 30% to 50% of the total amount of carbonate contained in the filtrate; the first-stage nanofiltration fresh water mainly comprises bromide ions, bicarbonate ions and a small amount of carbonate ions.
In one embodiment, the reverse osmosis unit 4 includes a reverse osmosis inlet 41, a reverse osmosis concentrate outlet 42, and a reverse osmosis fresh water outlet 43. The reverse osmosis inlet 41 is communicated with the first-stage nanofiltration fresh water outlet 32, so that the first-stage nanofiltration fresh water enters the reverse osmosis device 4 through the reverse osmosis inlet 41 and is concentrated in the reverse osmosis device 4 to improve the concentration of bromine salt, carbonate and bicarbonate, and simultaneously reverse osmosis fresh water with the water amount of 40-70% of that of the first-stage nanofiltration fresh water is obtained. Wherein, the concentrated reverse osmosis concentrated water is discharged from the reverse osmosis device 4 through the reverse osmosis concentrated water outlet 42, and the reverse osmosis fresh water is discharged from the reverse osmosis device 4 through the reverse osmosis fresh water outlet 43. In another embodiment, the reverse osmosis fresh water outlet 43 communicates with the backwash inlet 23 of the filtration device 2 to circulate the reverse osmosis fresh water for backwash treatment of the filtration device. In yet another embodiment, the reverse osmosis fresh water outlet 43 is in communication with the wash liquor inlet 11 of the wash apparatus 1 to recycle the reverse osmosis fresh water for the wash treatment of the PTA oxidation tail gas.
In one embodiment, the steam decarbonization device 5 comprises a liquid inlet 51, a liquid outlet 52 and a gas outlet 53. The liquid inlet 51 is communicated with the reverse osmosis concentrated water outlet 42, so that the reverse osmosis concentrated water enters the steam decarbonization device 5 through the liquid inlet 51. The reverse osmosis concentrated water is subjected to steam heating treatment in a steam decarbonization device 5 so as to ensure that HCO is generated3 -Conversion to CO by thermal decomposition3 2-And CO2，CO2CO is discharged from the steam decarboniser 5 with the steam from the gas outlet 533 2-The liquid dissolved therein is discharged from the steam decarbonising apparatus 5 through the liquid outlet 52. In one embodiment, the temperature of the steam heating treatment is 100 to 180 ℃.
The reverse osmosis concentrated water contains HCO with certain concentration3 -Because the separation efficiency of the nanofiltration membrane is limited, if the HCO is directly adjusted by adding acid and alkali, the HCO is separated3 -Turn into divalent ion, then enter into second grade nanofiltration device again and divide salt, not only need consume a large amount of acid-bases, make TDS (total dissolved solids) in the outer row waste water (be the second grade nanofiltration dense water) increase moreover, consequently the utility model discloses at first adopt the thermal process to strip the flash distillation decarbonization, make HCO3 -The transformation is carried out.
In one embodiment, the secondary nanofiltration device 6 comprises a secondary nanofiltration liquid inlet 61, a secondary nanofiltration fresh water outlet 62 and a secondary nanofiltration concentrated water outlet 63. The secondary nanofiltration liquid inlet 61 is communicated with the liquid outlet 52 of the vapor decarbonization device 5, so that the liquid generated by the vapor decarbonization device 5 enters the secondary nanofiltration device 6 through the secondary nanofiltration liquid inlet 61. According to the southward effect of the nanofiltration device on anions with different valence states, the liquid passes through the secondary nanofiltration device 6 and is separated into secondary nanofiltration fresh water and secondary nanofiltration concentrated water, and the secondary nanofiltration fresh water and the secondary nanofiltration concentrated water are respectively discharged out of the secondary nanofiltration device 6 from a secondary nanofiltration fresh water outlet 62 and a secondary nanofiltration concentrated water outlet 63. In one embodiment, the secondary nanofiltration concentrated water outlet 63 is communicated with the washing liquid inlet 11 of the washing device 1, so that the secondary nanofiltration concentrated water is circularly used for washing treatment of PTA oxidation tail gas, the solid alkali dosage is reduced, and the purpose of saving alkali dosage is achieved. In another embodiment, 40% to 80% of carbonate in the washing water may be separated through the nanofiltration operation of the primary nanofiltration device 3 and the secondary nanofiltration device 6. In yet another embodiment, the mass of the secondary nanofiltration concentrated water accounts for 10 to 30 percent of the mass of the liquid produced by the steam decarbonization device 5, and the secondary nanofiltration concentrated water contains carbonate with higher concentration; the secondary nanofiltration fresh water contains bromine salt, a small amount of bicarbonate and a small amount of carbonate.
In one embodiment, the evaporator 7 includes an evaporate inlet 71, an evaporate outlet 72, and a condensate outlet 73. The evaporation liquid inlet 71 is communicated with the secondary nanofiltration fresh water outlet 62, so that the secondary nanofiltration fresh water enters the evaporation device 7 through the evaporation liquid inlet 71. The evaporation device 7 adopts direct evaporation, multi-effect evaporation or MVR evaporation technology. The second-stage nanofiltration fresh water is further concentrated in the evaporation device 7 to improve the bromine salt concentration, or can be directly evaporated to a state where bromine salt can be crystallized to recover high-added-value bromine salt products, and steam generated by evaporation is condensed and then discharged through a condensed water outlet 73. In one embodiment, the condensed water outlet 73 is communicated with the washing liquid inlet 11 of the washing device 1, so that the condensed water can be recycled for washing treatment of the PTA oxidation tail gas, thereby saving the consumption of fresh water and further achieving the purpose of water saving.
The utility model discloses the defect that current treatment process need adopt the reductant not only can be avoided in the organic combination more than to the technology, can obtain the bromine salt solution or the bromine salt solid of high concentration high-efficiently moreover, improves the product added value, reaches resource utilization's purpose.
Fig. 2 is a schematic view of a PTA oxidation tail gas treatment and recovery system according to a second embodiment of the present invention. The same parts of the second embodiment as those of the first embodiment are not described herein again. As shown in fig. 2, the second embodiment of the present invention, compared with the first embodiment, further comprises a pH adjusting device 8, which comprises a liquid inlet 81, a liquid outlet 82 and an acid-base liquid inlet 83. The liquid inlet 81 is connected to the liquid outlet 52 of the steam decarbonizing device 5, so that the liquid generated by the steam decarbonizing device 5 can enter the pH value adjusting device 8 through the liquid inlet 81. The acid and alkali for adjusting pH value enters the pH value adjusting device 8 through the acid and alkali liquid inlet 83 to adjust the pH value of the liquid so as to enable HCO in the liquid3 -Further converted into divalent ions. The liquid after pH adjustment is discharged from the pH adjusting apparatus 8 through the liquid outlet 82.
The liquid outlet 82 is communicated with the secondary nanofiltration liquid inlet 61, so that the liquid with the adjusted pH value enters the secondary nanofiltration device 6 through the secondary nanofiltration liquid inlet 61 for further salt separation operation.
Fig. 3 is a schematic view of a PTA oxidation tail gas treatment and recovery system according to a third embodiment of the present invention. The parts of the third embodiment that are the same as the parts of the first embodiment are not described herein again. As shown in fig. 3, the third embodiment of the present invention is compared with the second embodiment, and further includes a pH adjusting device 8 and a flash evaporation device 9.
The flash apparatus 9 comprises a flash liquid inlet 91, a flash liquid outlet 92 and a vapour outlet 93. The flash liquid inlet 91 is in communication with the liquid outlet 52 of the steam decarbonization apparatus 5 such that liquid produced by the steam decarbonization apparatus 5 enters the flash apparatus 9 through the flash liquid inlet 91. The liquid is flashed in the flash evaporation device 9 to produce steam and a cooled flash evaporation liquid, and the steam is discharged from the flash evaporation device 9 through the steam outlet 93, and in one embodiment, the steam outlet 93 is communicated with the steam decarburization device 5 so that the steam is circulated back to the steam decarburization device 5 to heat the reverse osmosis concentrated water. The flash liquid exits the flash apparatus 9 through the flash liquid outlet 92.
The pH value adjusting device 8 comprises a liquid inlet 81, a liquid outlet 82 and an acid-alkali liquid inlet 83. The liquid inlet 81 is in communication with the flash liquid outlet 92 such that the flash liquid enters the pH adjusting device 8 through the liquid inlet 81. The acid and alkali for adjusting pH value enters the pH value adjusting device 8 through the acid and alkali liquid inlet 83 to adjust the pH value of the liquid so as to enable HCO in the liquid3 -Further converted into divalent ions. The liquid after pH adjustment is discharged from the pH adjusting apparatus 8 through the liquid outlet 82.
The liquid outlet 82 is communicated with the secondary nanofiltration liquid inlet 61, so that the liquid with the adjusted pH value enters the secondary nanofiltration device 6 through the secondary nanofiltration liquid inlet 61 for further salt separation operation.
This embodiment can make full use of the heat of the liquid that steam decarbonization device 5 produced, make its flash distillation liquid that produces steam and cooling in flash distillation device 9, steam can circulate and be used for steam decarbonization device 5's steam heating, and the energy saving has improved heat utilization efficiency.
Of course, in an embodiment, the PTA oxidation tail gas treatment and recovery system of the present invention may not include the pH adjusting device 8, but include the flash evaporation device 9, and the present invention is not limited thereto.
The utility model also provides a PTA oxidation tail gas treatment and recovery method, include:
step 1, washing PTA oxidized tail gas, and filtering the obtained washing liquid;
step 2, carrying out primary nanofiltration treatment on the filtrate obtained in the step 1 to obtain primary nanofiltration fresh water;
step 3, performing reverse osmosis treatment on the primary nanofiltration fresh water to obtain reverse osmosis concentrated water;
step 4, carrying out steam decarburization treatment on the reverse osmosis concentrated water;
step 5, carrying out secondary nanofiltration treatment on the liquid obtained in the step 4 to obtain secondary nanofiltration fresh water; and
and 6, evaporating the secondary nanofiltration fresh water to recover bromine salt.
In one embodiment, the method for treating and recovering PTA oxidation tail gas comprises:
washing the PTA oxidation tail gas in a reverse washing mode, wherein the washing liquid is alkali liquor. The washing wastewater produced after washing is subjected to a filtration treatment, and the filtration apparatus is, for example, a manganese sand filtration apparatus, to remove suspended matter. After the manganese sand filtering device operates for a period of time, backwashing treatment is needed, and wastewater obtained by backwashing can be discharged into a factory biochemical treatment system for further treatment.
The filtrate after filtration is subjected to primary nanofiltration treatment to achieve the aim of pre-salt separation. And (3) separating the filtrate after primary nanofiltration treatment to obtain primary nanofiltration concentrated water and primary nanofiltration fresh water, wherein in one embodiment, the primary nanofiltration concentrated water contains 30 to 50 percent of carbonate in the filtrate and can be discharged to a factory biochemical treatment system for further treatment.
And performing reverse osmosis treatment on the primary nanofiltration fresh water obtained by the primary nanofiltration treatment to further concentrate the primary nanofiltration fresh water, so as to improve the concentrations of bromine salt, carbonate and bicarbonate in the primary nanofiltration fresh water. In one embodiment, the reverse osmosis concentrate produced by reverse osmosis has a concentration of bromide, carbonate, bicarbonate that is 3-6 times (e.g., 4 times) greater than the original concentration. And simultaneously, reverse osmosis fresh water (for example, 50%) which is 40 to 70 percent of the mass of the primary nanofiltration fresh water is generated, one part of the reverse osmosis fresh water can be circularly used for the back washing water of the filtering device, and the other part of the reverse osmosis fresh water can be used for the spray water of the washing device, so that the aim of reducing the consumption of fresh make-up water is fulfilled.
And carrying out steam decarburization treatment on the reverse osmosis concentrated water. Namely, the reverse osmosis concentrated water is subjected to steam heating treatment at the temperature of 100-180 ℃ to ensure that HCO is generated3 -Conversion to CO by thermal decomposition3 2-And CO2，CO2And discharging after cooling. In one embodiment, the liquid after the steam decarburization treatment is subjected to a flash evaporation treatment to reduce the temperature of the liquid, and simultaneously, steam is generated to be recycled to the steam decarburization treatment process, so that the energy consumption is reduced.
In another embodiment, the flash liquid obtained after the flash treatment is subjected to a pH adjustment step to adjust the pH of HCO3 -Further conversion to CO3 2-。
Then, the liquid after the pH value adjustment is subjected to secondary nanofiltration treatment, thereby separating the liquid into secondary nanofiltration concentrated water and secondary nanofiltration fresh water. In one embodiment, the secondary nanofiltration concentrated water contains a substantial amount of carbonate, which is 10% to 30% by mass of the liquid. In another embodiment, 40% to 80% of the carbonate in the washing liquid may be separated after the primary nanofiltration treatment and the secondary nanofiltration treatment. The second-stage nanofiltration concentrated water can be circularly returned to the washing step to wash the PTA oxidation tail gas so as to reduce the addition of solid alkali and achieve the purpose of saving the alkali consumption. The secondary nanofiltration fresh water contains bromine salt, a small amount of bicarbonate and a small amount of carbonate.
Finally, evaporating the second-stage nanofiltration fresh water, wherein the evaporation process can adopt direct evaporation, multiple-effect evaporation or MVR evaporation; the evaporation process mainly aims to further improve the concentration of the bromine salt in the secondary nanofiltration fresh water or directly evaporate the bromine salt to a state that the bromine salt can be crystallized so as to achieve the aim of recovering the bromine salt. Meanwhile, the evaporated secondary steam can be condensed and then enters the washing treatment process to be used as make-up water.
The utility model discloses a purpose that bromine of PTA oxidation tail gas washing tower waste water was retrieved, is reduced alkali consumption and water conservation is realized to preliminary treatment + receive and strain salt + membrane concentration + hot decarburization + multiple effect or MVR evaporative concentration or crystallization.
Of course, the present invention can have other embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present invention without departing from the spirit and the essence of the present invention, and these corresponding changes and modifications should fall within the protection scope of the claims of the present invention.
Claims (10)
1. The PTA oxidation tail gas treatment and recovery system is characterized by comprising:
the washing device is communicated with the PTA oxidation tail gas discharge port;
a filtering device communicated with the washing device;
the primary nanofiltration device is communicated with the filtering device;
the reverse osmosis device is communicated with the primary nanofiltration device;
the steam decarbonization device is communicated with the reverse osmosis device;
the secondary nanofiltration device is communicated with the steam decarbonization device; and
and the evaporation device is communicated with the secondary nanofiltration device.
2. The PTA oxidation tail gas treatment and recovery system of claim 1, wherein the filtration device is a manganese sand filtration device, the filtration device comprising a filtrate inlet in communication with a scrubbing liquid outlet of the scrubbing device and a filtrate outlet in communication with the primary nanofiltration device.
3. The PTA oxidation tail gas treatment and recovery system of claim 2, wherein the primary nanofiltration device comprises a primary nanofiltration liquid inlet, a primary nanofiltration fresh water outlet and a primary nanofiltration concentrated water outlet, the primary nanofiltration liquid inlet is communicated with the liquid outlet, the primary nanofiltration fresh water outlet is communicated with the reverse osmosis device, and the primary nanofiltration concentrated water outlet is connected with an external biochemical treatment system.
4. The PTA oxidation tail gas treatment and recovery system of claim 1, wherein the reverse osmosis device comprises a reverse osmosis fresh water outlet in communication with a backwash inlet of the filtration device and/or a wash inlet of the washing device and a reverse osmosis concentrated water outlet in communication with the steam decarbonization device.
5. The PTA oxidation tail gas treatment and recovery system of claim 1, wherein the vapor decarbonization device comprises a gas outlet in communication with the outside and a liquid outlet in communication with the secondary nanofiltration device.
6. The PTA oxidation tail gas treatment and recovery system of claim 1, wherein the secondary nanofiltration device comprises a secondary nanofiltration fresh water outlet and a secondary nanofiltration concentrated water outlet, the evaporation device comprises an evaporation liquid inlet, an evaporation liquid outlet and a condensed water outlet, the secondary nanofiltration fresh water outlet is communicated with the evaporation liquid inlet, and the secondary nanofiltration concentrated water outlet and the condensed water outlet are respectively communicated with a washing liquid inlet of the washing device.
7. The PTA oxidation tail gas treatment and recovery system of claim 5 further comprising a flash apparatus in communication with the liquid outlet of the steam decarbonization apparatus, the flash apparatus comprising a steam outlet and a flash liquid outlet, the steam outlet in communication with the steam decarbonization apparatus.
8. The PTA oxidation tail gas treatment and recovery system of claim 7, further comprising a pH adjustment device in communication with a flash liquid outlet of the flash apparatus.
9. The PTA oxidation tail gas treatment and recovery system of claim 5 further comprising a pH adjusting means in communication with the liquid outlet of the steam decarbonization apparatus.
10. The PTA oxidation tail gas treatment and recovery system of claim 2, wherein the scrubbing device further comprises a PTA oxidation tail gas inlet, a PTA oxidation tail gas outlet, and a scrubbing liquid inlet, the PTA oxidation tail gas inlet being in communication with a PTA oxidation tail gas discharge outlet.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113248068A (en) * | 2021-04-16 | 2021-08-13 | 天华化工机械及自动化研究设计院有限公司 | Resourceful treatment method and system for PTA oxidation tail gas washing tower discharge liquid |
| CN113321259A (en) * | 2021-04-16 | 2021-08-31 | 天华化工机械及自动化研究设计院有限公司 | Energy-saving decarbonization method and system for PTA (pure terephthalic acid) oxidation tail gas washing tower discharge liquid |
| CN113735353A (en) * | 2020-05-29 | 2021-12-03 | 天华化工机械及自动化研究设计院有限公司 | PTA (pure terephthalic acid) oxidized tail gas treatment and recovery system and method |
| CN114906964A (en) * | 2021-02-09 | 2022-08-16 | 大连波美科技有限公司 | PTA wastewater treatment system and application method |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113735353A (en) * | 2020-05-29 | 2021-12-03 | 天华化工机械及自动化研究设计院有限公司 | PTA (pure terephthalic acid) oxidized tail gas treatment and recovery system and method |
| CN113735353B (en) * | 2020-05-29 | 2024-02-09 | 天华化工机械及自动化研究设计院有限公司 | PTA oxidation tail gas treatment and recovery system and method |
| CN114906964A (en) * | 2021-02-09 | 2022-08-16 | 大连波美科技有限公司 | PTA wastewater treatment system and application method |
| CN114906964B (en) * | 2021-02-09 | 2023-07-21 | 大连波美科技有限公司 | PTA wastewater treatment system and application method |
| CN113248068A (en) * | 2021-04-16 | 2021-08-13 | 天华化工机械及自动化研究设计院有限公司 | Resourceful treatment method and system for PTA oxidation tail gas washing tower discharge liquid |
| CN113321259A (en) * | 2021-04-16 | 2021-08-31 | 天华化工机械及自动化研究设计院有限公司 | Energy-saving decarbonization method and system for PTA (pure terephthalic acid) oxidation tail gas washing tower discharge liquid |
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