CN215947029U - Light salt brine embrane method deNOx systems - Google Patents
Light salt brine embrane method deNOx systems Download PDFInfo
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- CN215947029U CN215947029U CN202122282614.1U CN202122282614U CN215947029U CN 215947029 U CN215947029 U CN 215947029U CN 202122282614 U CN202122282614 U CN 202122282614U CN 215947029 U CN215947029 U CN 215947029U
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Abstract
The utility model discloses a denitration system for dilute brine by a membrane method, which comprises a pretreatment device, a membrane separation device and a freezing denitration device, wherein a water outlet of a dilute brine buffer tank of the pretreatment device is connected with a water inlet of a high-pressure pump of the membrane separation device through a pipeline; the nitrate-rich brine outlet of the nanofiltration membrane device of the membrane separation device is connected with the water inlet of the precooler of the freezing denitrification device through a pipeline. The advantages are that: by using the membrane method denitration system, no chemical reagent is required to be added into the brine system, the quality of brine is not influenced, secondary pollutants are not generated, the operation is simple, the operation cost is low, and the environmental protection requirement is met.
Description
The technical field is as follows:
the utility model relates to the technical field of denitration equipment, in particular to a light salt brine membrane method denitration system.
Background art:
the method for denitration of the brine mainly comprises a barium chloride method, a calcium method, a freezing method and a membrane method, the barium chloride chemical precipitation method is widely used in China, the current efficiency in the ion membrane electrolysis can be reduced when barium ions exceed the standard, the barium ions are easy to react with sodium hydroxide to generate precipitates, the service life of the ion membrane is influenced, and the barium chloride is a high-toxicity hazardous chemical product and does not meet the requirement of environmental protection.
The membrane method denitration is an advanced method at present, but the existing membrane method denitration process still has some problems: firstly, the heat exchange effect of a heat exchanger in the pretreatment unit is not ideal, and the energy consumption is high; secondly, after the membrane separation device operates for a long time, the operating pressure can be increased, and a membrane method denitration system has potential safety hazards; thirdly, after the whole system stops running, the nitrate-poor water of the membrane separation device instantly flows back to form back pressure, so that the nanofiltration membrane is easily damaged; fourthly, the conventional method used by the post-treatment unit at present is a freezing crystallization method, and a precooler uses cooling water for cooling, so that the problems of resource waste, high energy consumption and the like exist, and the ideal operation effect is difficult to achieve; fifthly, the automation control level of the whole membrane denitration process is low.
The utility model has the following contents:
the utility model aims to provide a light brine membrane method denitration system, which solves the problems of unsatisfactory heat exchange effect, high equipment energy consumption, high pressure rise in the membrane separation process and the like in the pretreatment process.
The utility model is implemented by the following technical scheme: a membrane method denitration system for dilute brine comprises a pretreatment device, a membrane separation device and a freezing denitration device; the water outlet of the fresh brine buffer tank of the pretreatment device is connected with the water inlet of the high-pressure pump of the membrane separation device through a pipeline, the nitrate-poor brine outlet of the nanofiltration membrane device of the membrane separation device is connected with the cold source inlet of the primary heat exchanger of the pretreatment device through a pipeline, and the cold source outlet of the primary heat exchanger of the pretreatment device is connected with the primary brine tank through a pipeline; and a nitrate-rich salt water outlet of a nanofiltration membrane device of the membrane separation device is connected with a water inlet of a precooler of the freezing denitrification device through a pipeline.
Preferably, the pretreatment device comprises a light brine storage tank, a light brine booster pump, a primary heat exchanger, a secondary heat exchanger, an activated carbon filter, a cartridge filter and a light brine buffer tank; a dechlorination light salt water pipeline is connected with a water inlet of the light salt water storage tank, and a water outlet of the light salt water storage tank is connected with a water inlet of the light salt water booster pump through a pipeline; a hydrochloric acid inlet and a sodium sulfite inlet are sequentially formed in a pipeline connecting a water outlet of the dilute brine storage tank and a water inlet of the dilute brine booster pump, the hydrochloric acid inlet is connected with a hydrochloric acid metering pump through a pipeline, the sodium sulfite inlet is connected with a sodium sulfite metering pump through a pipeline, the hydrochloric acid metering pump is connected with the hydrochloric acid storage tank through a pipeline, and the sodium sulfite metering pump is connected with the sodium sulfite storage tank through a pipeline; the water outlet of the dilute brine booster pump is connected with the water inlet of the primary heat exchanger through a pipeline, the water outlet of the primary heat exchanger is connected with the water inlet of the secondary heat exchanger through a pipeline, the cold source inlet of the secondary heat exchanger is connected with the first circulating water supply pipeline, and the cold source outlet of the secondary heat exchanger is connected with the first circulating water return pipeline; the water outlet of the secondary heat exchanger is connected with the water inlet of the activated carbon filter through a pipeline, the water outlet of the activated carbon filter is connected with the water inlet of the security filter through a pipeline, and the water outlet of the security filter is connected with the water inlet of the dilute brine buffer tank through a pipeline.
Preferably, a first ORP measuring instrument is arranged on the dechlorination fresh salt water pipeline, a fresh salt water storage tank bypass port is further arranged on the dechlorination fresh salt water pipeline, the fresh salt water storage tank bypass port is connected with the bypass pipeline, a fresh salt water storage tank bypass valve is installed at the fresh salt water storage tank bypass port, a fresh salt water storage tank water inlet valve is installed at the fresh salt water storage tank water inlet, the signal output end of the first ORP measuring instrument is in signal connection with the signal input end of the controller, and the signal output end of the controller is in signal connection with the fresh salt water storage tank water inlet valve and the signal output end of the fresh salt water storage tank bypass valve respectively.
Preferably, a first pH measuring instrument and a second ORP measuring instrument are arranged on a pipeline connecting the sodium sulfite inlet and the water inlet of the dilute brine booster pump, a hydrochloric acid inlet valve is installed at the hydrochloric acid inlet, a sodium sulfite inlet valve is installed at the sodium sulfite inlet, the signal output end of the first pH measuring instrument is in signal connection with the signal input end of the controller, and the signal output end of the controller is in signal connection with the signal output end of the hydrochloric acid inlet valve; and the signal output end of the second ORP measuring instrument is in signal connection with the signal input end of the controller, and the signal output end of the controller is in signal connection with the signal output end of the sodium sulfite inlet valve.
Preferably, a first temperature sensor is arranged on a pipeline connecting a water outlet of the secondary heat exchanger and a water inlet of the activated carbon filter, a first circulating water inlet valve is arranged on the first circulating water inlet pipeline, a signal output end of the first temperature sensor is in signal connection with a signal input end of the controller, and a signal output end of the controller is in signal connection with a signal output end of the first circulating water inlet valve.
Preferably, a third ORP measuring instrument, a second pH measuring instrument and a second temperature sensor are arranged on a pipeline connecting the water outlet of the activated carbon filter and the water inlet of the security filter, an activated carbon filter bypass port is further formed on a pipeline connecting the water outlet of the activated carbon filter and the water inlet of the security filter, the activated carbon filter bypass port is connected with a bypass pipeline, and an activated carbon filter bypass valve is installed at the activated carbon filter bypass port; the water inlet of the security filter is provided with a water inlet valve of the security filter, the signal output ends of the third ORP measuring instrument, the second pH measuring instrument and the second temperature sensor are respectively in signal connection with the signal input end of the controller, and the signal output end of the controller is respectively in signal connection with the water inlet valve of the security filter and the bypass valve of the activated carbon filter.
Preferably, the membrane separation device comprises a high-pressure pump and a nanofiltration membrane device, and a water outlet of the high-pressure pump is connected with a water inlet of the nanofiltration membrane device through a pipeline; an anti-backpressure valve is arranged at a nitrate-poor brine outlet of the nanofiltration membrane device; the water inlet of the high-pressure pump is connected with the water outlet of the cleaning filter through a pipeline, the water inlet of the cleaning filter is connected with the water outlet of the cleaning pump through a pipeline, and the water inlet of the cleaning pump is connected with the water outlet of the cleaning water tank through a pipeline.
Preferably, the freezing and denitration device comprises a precooler, a crystallization tank, a mother liquor circulating water pump, a mother liquor cooler, a crystal slurry pump, a nitrate precipitation tank, a centrifuge, a mirabilite storage tank, a backwater storage tank and a backwater delivery pump; an alkali liquor inlet is formed in a pipeline connecting a nitrate-rich water outlet of the nanofiltration membrane device and a water inlet of the precooler, the alkali liquor inlet is connected with an alkali metering pump through a pipeline, and the alkali metering pump is connected with an alkali liquor storage tank through a pipeline; the water outlet of the precooler is connected with the water inlet of the crystallization tank through a pipeline, the clear liquid outlet of the crystallization tank is connected with the water inlet of the mother liquid circulating water pump through a pipeline, the water outlet of the mother liquid circulating water pump is connected with the water inlet of the mother liquid cooler through a pipeline, and the water outlet of the mother liquid cooler is connected with the water inlet of the crystallization tank through a first backflow pipeline; a clear liquid outlet of the crystallization tank is connected with a water inlet of the precooler through a second backflow pipeline; a cold source inlet of the mother liquor cooler is connected with a second circulating water supply pipeline, and a cold source outlet of the mother liquor cooler is connected with a second circulating water return pipeline;
the water inlet of the mother liquor cooler is connected with the water outlet of a flushing pump through a pipeline, the water inlet of the flushing pump is connected with the water outlet of a flushing liquid tank through a pipeline, and the water inlet of the flushing liquid tank is connected with the nitrate-poor water outlet of the membrane separation device through a pipeline;
the crystallization outlet of crystallization tank with the import of magma pump passes through the pipeline and links to each other, the export of magma pump with the import of depositing the nitre groove passes through the pipeline and links to each other, the crystallization outlet of depositing the nitre groove with centrifuge's import passes through the pipeline and links to each other, centrifuge's crystallization outlet with the import of mirabilite storage tank passes through the pipeline and links to each other, deposit the nitre groove with centrifuge's clear solution export all with the water inlet of return water storage tank passes through the pipeline and links to each other, the delivery port of return water storage tank with the water inlet of return water delivery pump passes through the pipeline and links to each other, the delivery port of return water delivery pump with the water inlet of crystallization tank passes through the pipeline and links to each other.
Preferably, a third pH measuring instrument is arranged on a pipeline connecting the alkali liquor inlet and the water inlet of the precooler, an alkali liquor inlet valve is installed at the alkali liquor inlet, a signal output end of the third pH measuring instrument is in signal connection with a signal input end of the controller, and a signal output end of the controller is in signal connection with a signal output end of the alkali liquor inlet valve.
Preferably, a third temperature sensor is arranged on the first return pipeline, a second circulating water inlet valve is arranged on the second circulating water inlet pipeline, a signal output end of the third temperature sensor is in signal connection with a signal input end of the controller, and a signal output end of the controller is in signal connection with a signal output end of the second circulating water inlet valve; the second return pipeline is provided with a fourth temperature sensor, the second return pipeline is also provided with a clear liquid return valve of the crystallization tank, the signal output end of the fourth temperature sensor is in signal connection with the signal input end of the controller, and the signal output end of the controller is in signal connection with the clear liquid return valve of the crystallization tank.
The utility model has the advantages that: the denitration by adopting the membrane method is a physical process, does not need to add chemical reagents into a brine system, does not influence the quality of brine, does not generate secondary pollutants, is simple to operate, has low operating cost and meets the requirement of environmental protection; the primary heat exchanger and the secondary heat exchanger are adopted for secondary heat exchange, the heat exchange effect is ideal, the temperature of the saline water can be effectively reduced, and the damage to a nanofiltration membrane is avoided; the primary heat exchanger utilizes the nitrate-poor water separated by the nanofiltration membrane device as a cold source to exchange heat, the nitrate-poor water after heat exchange enters the primary brine tank, and the waste heat of the nitrate-poor water is utilized to carry out salt melting, so that the repeated utilization of the nitrate-poor water is realized, the resources are saved, and the energy consumption is reduced; the back pressure prevention valve is arranged to prevent the nitrate-poor water from instantly flowing back to the nanofiltration membrane device after the device is stopped, and the nanofiltration membrane is damaged by back pressure; the cleaning system is arranged to clean the nanofiltration membrane device, so that the operating pressure of the nanofiltration membrane device can be effectively reduced, and potential safety hazards are avoided; the freezing and denitration device utilizes the backwater storage tank and the backwater delivery pump to deliver the crystallized clear liquid to the crystallization tank for continuous recycling, so that part of cold energy of the crystallized clear liquid is recovered to the greatest extent, the purpose of circulating refrigeration is realized, the energy consumption of the freezing and denitration device is reduced, and the waste of energy consumption caused by discharging the clear liquid with low temperature to a salt melting process is avoided; an ORP automatic control system, a pH value automatic control system and a temperature automatic control system are arranged, the operation is intelligent, and the safe and efficient operation of the system is realized.
Description of the drawings:
in order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic view of a pretreatment apparatus;
FIG. 2 is a schematic structural view of a membrane separation apparatus;
FIG. 3 is a schematic structural view of a freezing denitration device;
FIG. 4 is a control schematic of the present invention;
the system comprises a pretreatment device 1, a fresh salt water storage tank 1.1, a fresh salt water booster pump 1.2, a primary heat exchanger 1.3, a secondary heat exchanger 1.4, an activated carbon filter 1.5, a cartridge filter 1.6, a fresh salt water buffer tank 1.7, a first ORP measuring instrument 1.8, a fresh salt water storage tank water inlet valve 1.9, a fresh salt water storage tank bypass valve 1.10, a controller 1.11, a first pH measuring instrument 1.12, a second ORP measuring instrument 1.13, a hydrochloric acid inlet valve 1.14, a sodium sulfite inlet valve 1.15, a hydrochloric acid metering pump 1.16, a sodium sulfite metering pump 1.17, a hydrochloric acid storage tank 1.18, a sodium sulfite storage tank 1.19, a first temperature sensor 1.20, a first circulating water inlet valve 1.21, a third ORP measuring instrument 1.22, a second pH measuring instrument 1.23, a second temperature sensor 1.24, a cartridge filter water inlet valve 1.25, an activated carbon filter bypass valve 1.26, a membrane separation device 2, a high-pressure pump 2.1, a nanofiltration membrane device 2.2, a nanofiltration membrane device 2.3, a back pressure valve 2.3, a cleaning filter 2.5, a cleaning pump 2.5, 2.6 parts of a cleaning water tank, 3 parts of a freezing and denitration device, 3.1 parts of a precooler, 3.2 parts of a crystallization tank, 3.3 parts of a mother liquor circulating water pump, 3.4 parts of a mother liquor cooler, 3.5 parts of a crystal slurry pump, 3.6 parts of a nitrate precipitation tank, 3.7 parts of a centrifugal machine, 3.8 parts of a mirabilite storage tank, 3.9 parts of a return water storage tank, 3.10 parts of a return water delivery pump, 3.11 parts of an alkali metering pump, 3.12 parts of an alkali storage tank, 3.13 parts of a third pH measuring instrument, 3.14 parts of an alkali liquor inlet valve, 3.15 parts of a third temperature sensor, 3.16 parts of a second circulating water inlet valve, 3.17 parts of a fourth temperature sensor, 3.18 parts of a clear liquid return valve of the crystallization tank, 3.19 parts of a flushing pump and 3.20 parts of a flushing liquid tank
The specific implementation mode is as follows:
the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The primary brine enters a chelating resin tower through a primary brine tank, secondary refined brine obtained through resin exchange enters a secondary refined brine tank, the secondary refined brine is pumped into an electrolysis process by a secondary refined brine pump, dechlorinated light brine electrolyzed by an electrolysis tank is sent into a light brine membrane method denitration system, and the light brine membrane method denitration system comprises a pretreatment device 1, a membrane separation device 2 and a freezing denitration device 3; the water outlet of a fresh brine buffer tank 1.7 of the pretreatment device 1 is connected with the water inlet of a high-pressure pump 2.1 of the membrane separation device 2 through a pipeline, the nitrate-poor brine outlet of a nanofiltration membrane device 2.2 of the membrane separation device 2 is connected with the cold source inlet of a primary heat exchanger 1.3 of the pretreatment device 1 through a pipeline, and the cold source outlet of the primary heat exchanger 1.3 of the pretreatment device 1 is connected with a primary brine tank through a pipeline; the nitrate-rich brine outlet of the nanofiltration membrane device 2.2 of the membrane separation device 2 is connected with the water inlet of the precooler 3.1 of the freezing denitrification device 3 through a pipeline.
As shown in fig. 1, the pretreatment device 1 comprises a light salt brine storage tank 1.1, a light salt brine booster pump 1.2, a primary heat exchanger 1.3, a secondary heat exchanger 1.4, an activated carbon filter 1.5, a cartridge filter 1.6 and a light salt brine buffer tank 1.7; a dechlorination light salt water pipeline is connected with a water inlet of a light salt water storage tank 1.1, a first ORP measuring instrument 1.8 is arranged on the dechlorination light salt water pipeline, a water inlet valve 1.9 of the light salt water storage tank is arranged at the water inlet of the light salt water storage tank 1.1, a bypass port of the light salt water storage tank is also arranged on the dechlorination light salt water pipeline, the bypass port of the light salt water storage tank is connected with the bypass pipeline, a bypass valve 1.10 of the light salt water storage tank is arranged at the bypass port of the light salt water storage tank, the signal output end of the first ORP measuring instrument 1.8 is in signal connection with the signal input end of a controller 1.11, the signal output end of the controller 1.11 is in signal connection with the signal output ends of the water inlet valve 1.9 of the light salt water storage tank and the bypass valve 1.10 of the light salt water storage tank respectively, if the first ORP measuring instrument 1.8 measures that the free chlorine index in the dechlorination light salt water is qualified, the light salt water storage tank is opened, and the light salt water inlet valve 1.9 of the light salt water storage tank is fed into the light salt water storage tank 1.1; if the measured free chlorine in the dechlorinated light salt brine exceeds the standard, automatically switching a bypass valve 1.10 of a light salt brine storage tank to discharge the light salt brine with the free chlorine exceeding the standard, and preventing the light salt brine with the free chlorine exceeding the standard from entering a membrane separation device 2 to damage a nanofiltration membrane;
a water outlet of the dilute brine storage tank 1.1 is connected with a water inlet of the dilute brine booster pump 1.2 through a pipeline, a hydrochloric acid inlet and a sodium sulfite inlet are further sequentially arranged on the pipeline connecting the water outlet of the dilute brine storage tank 1.1 with the water inlet of the dilute brine booster pump 1.2, a first pH measuring instrument 1.12 and a second ORP measuring instrument 1.13 are arranged on the pipeline connecting the sodium sulfite inlet with the water inlet of the dilute brine booster pump 1.2, a hydrochloric acid inlet valve 1.14 is arranged at the hydrochloric acid inlet, a sodium sulfite inlet valve 1.15 is arranged at the sodium sulfite inlet, the hydrochloric acid inlet is connected with a hydrochloric acid metering pump 1.16 through a pipeline, the sodium sulfite inlet is connected with a sodium sulfite metering pump 1.17 through a pipeline, the hydrochloric acid metering pump 1.16 is connected with a hydrochloric acid storage tank 1.18 through a pipeline, and the sodium sulfite metering pump 1.17 is connected with a sodium sulfite storage tank 1.19 through a pipeline; because the pH value of the electrolyzed weak brine is generally 9-11, the pH value of the weak brine needs to be adjusted to be 4-8 by the first pH measuring instrument 1.12, if the first pH measuring instrument 1.12 detects that the pH index in the weak brine is unqualified, the hydrochloric acid inlet valve 1.14 can be opened according to the signal of the first pH measuring instrument 1.12, and hydrochloric acid is added to meet the operation requirement of the membrane separation device 2; if the second ORP measuring instrument 1.13 detects that the index of free chlorine in the dilute brine is not qualified, a sodium sulfite inlet valve 1.15 can be opened according to a signal of the second ORP measuring instrument 1.13, and the added amount of sodium sulfite is added so as to meet the operation requirement of the membrane separation device 2;
the water outlet of the dilute brine booster pump 1.2 is connected with the water inlet of the primary heat exchanger 1.3 through a pipeline, the water outlet of the primary heat exchanger 1.3 is connected with the water inlet of the secondary heat exchanger 1.4 through a pipeline, the cold source inlet of the primary heat exchanger 1.3 is connected with the nitrate-poor water outlet of the nanofiltration membrane device 2.2 through a pipeline, the cold source outlet of the primary heat exchanger 1.3 is connected with the primary brine tank through a pipeline, the primary heat exchanger 1.3 utilizes the nitrate-poor water separated by the nanofiltration membrane device 2.2 as a cold source to carry out heat exchange, the nitrate-poor water after heat exchange enters the primary brine tank, and salt is converted by using waste heat, so that the reuse of the nitrate-poor water is realized, the resources are saved, and the energy consumption is reduced; a cold source inlet of the secondary heat exchanger 1.4 is connected with the first circulating water supply pipeline, and a cold source outlet of the secondary heat exchanger 1.4 is connected with the first circulating water return pipeline for heat exchange, so that the aim of cooling is fulfilled;
the water outlet of the secondary heat exchanger 1.4 is connected with the water inlet of the activated carbon filter 1.5 through a pipeline, a first temperature sensor 1.20 is arranged on the pipeline connecting the water outlet of the secondary heat exchanger 1.4 with the water inlet of the activated carbon filter 1.5, a first circulating water inlet valve 1.21 is arranged on a first circulating water inlet pipeline, the signal output end of the first temperature sensor 1.20 is in signal connection with the signal input end of the controller 1.11, and the signal output end of the controller 1.11 is in signal connection with the signal output end of the first circulating water inlet valve 1.21; if the temperature of the dilute brine detected by the first temperature sensor 1.20 exceeds the allowable range, the first circulating water inlet valve 1.21 can be opened according to a signal of the first temperature sensor 1.20, so that the aim of automatically controlling the heat exchange temperature of the dilute brine is fulfilled, the temperature of the dilute brine is ensured to be always stabilized in the set range, and the influence of the excessively low temperature on the flux of the nanofiltration membrane and the damage of the nanofiltration membrane caused by the excessively high temperature are avoided;
the filter material filled in the activated carbon filter 1.5 is activated carbon particles, the microporous structure of the particles can absorb residual chlorine in water, although the residual chlorine in the fresh brine is trace during normal operation, the activated carbon filter 1.5 is arranged to ensure that the content of free chlorine in the fresh brine is less than 0.1mg/L under normal conditions in consideration of the possibility of residual chlorine permeation caused by a certain equipment fault and damage to the nanofiltration membrane, so that the nanofiltration membrane in the nanofiltration membrane device 2.2 is prevented from being oxidized and degraded by the residual chlorine, meanwhile, the activated carbon filter 1.5 can also absorb low-molecular organic pollutants and the like leaked from a preceding stage, has obvious adsorption and removal effects on heavy metal ions, COD and the like in water, and can also reduce peculiar smell, chroma and odor in the water;
the water outlet of the active carbon filter 1.5 is connected with the water inlet of the safety filter 1.6 through a pipeline, a third ORP measuring instrument 1.22, a second pH measuring instrument 1.23 and a second temperature sensor 1.24 are arranged on a pipeline connecting the water outlet of the activated carbon filter 1.5 and the water inlet of the cartridge filter 1.6, a water inlet valve 1.25 of the security filter is arranged at the water inlet of the security filter 1.6, a bypass port of the activated carbon filter is arranged on a pipeline connecting the water outlet of the activated carbon filter 1.5 and the water inlet of the security filter 1.6, the bypass port of the activated carbon filter is connected with a bypass pipeline, the signal output ends of a third ORP measuring instrument 1.22, a second pH measuring instrument 1.23 and a second temperature sensor 1.24 are respectively in signal connection with the signal input end of a controller 1.11, and the signal output end of the controller 1.11 is respectively in signal connection with a security filter water inlet valve 1.25 and an active carbon filter bypass valve 1.26; when free chlorine appears in the dilute brine in the water outlet of the activated carbon filter 1.5, the pH value or the temperature exceeds the standard, the bypass valve 1.26 of the activated carbon filter is automatically switched to discharge the dilute brine with the exceeding parameters, so that the damage to the nanofiltration membrane caused by the exceeding parameters is prevented when the dilute brine is unqualified; when the free chlorine, pH and temperature indexes of the light brine are qualified, the light brine enters a cartridge filter 1.6 through a water outlet of an activated carbon filter 1.5, and the cartridge filter 1.6 can prevent micro particles from entering a membrane method separation device to block a nanofiltration membrane; the water outlet of the cartridge filter 1.6 is connected with the water inlet of the light salt water buffer tank 1.7 through a pipeline, and the light salt water enters the light salt water buffer tank 1.7 after being filtered by the cartridge filter 1.6.
As shown in fig. 2, the membrane separation device 2 comprises a high-pressure pump 2.1 and a nanofiltration membrane device 2.2, wherein a water outlet of the high-pressure pump 2.1 is connected with a water inlet of the nanofiltration membrane device 2.2 through a pipeline; the nanofiltration membrane in the nanofiltration membrane device 2.2 is a high-efficiency nanofiltration membrane suitable for neutral alkaline environment, the diameter of the membrane pores of the nanofiltration membrane is just between divalent ions and has negative charges, so the nanofiltration membrane has extremely high removal capacity on sulfate ions, chloride ions and sodium ions have good permeation capacity, and light brine passing through the nanofiltration membrane is separated into nitrate-poor brine and nitrate-rich brine, and the nitrate-poor brine contains trace Na2SO4Can be used as a cold source of the primary heat exchanger 1.3The nitrate-rich water is used and contains Na2SO4The nitrate-rich brine is more than or equal to 60g/L and enters a freezing and denitration device 3; a backpressure-preventing valve 2.3 is arranged at a lean nitrate water outlet of the nanofiltration membrane device 2.2, so that the phenomenon that the lean nitrate water instantaneously flows back to the nanofiltration membrane device 2.2 after the device is stopped and a nanofiltration membrane is damaged by backpressure is avoided;
after the membrane separation device 2 is operated for a long time, certain pollution which is difficult to wash away exists, for example, long-term trace salt scaling and organic matter accumulation can cause the performance of a nanofiltration membrane to be reduced, the operation pressure is increased, in order to ensure that the membrane separation device 2 is stably operated, the water inlet of the high-pressure pump 2.1 is connected with the water outlet of the cleaning filter 2.4 through a pipeline, the water inlet of the cleaning filter 2.4 is connected with the water outlet of the cleaning pump 2.5 through a pipeline, the water inlet of the cleaning pump 2.5 is connected with the water outlet of the cleaning water tank 2.6 through a pipeline, when a light salt water membrane method denitration system stops operating, the cleaning state can be switched to, pure water is used for cleaning the high-pressure pump 2.1 and the nanofiltration membrane device 2.2, and the cleaned cleaning liquid returns to the pretreatment device 1, thereby avoiding crystallization blockage of the nanofiltration membrane and influencing the separation effect of the membrane separation device 2.
As shown in fig. 3, the freezing and denitration device 3 comprises a precooler 3.1, a crystallization tank 3.2, a mother liquor circulating water pump 3.3, a mother liquor cooler 3.4, a crystal slurry pump 3.5, a nitrate precipitation tank 3.6, a centrifuge 3.7, a mirabilite storage tank 3.8, a backwater storage tank 3.9 and a backwater transfer pump 3.10; an alkali liquor inlet is arranged on a pipeline connecting a nitrate-rich water outlet of the nanofiltration membrane device 2.2 and a water inlet of the precooler 3.1, the alkali liquor inlet is connected with an alkali metering pump 3.11 through a pipeline, and the alkali metering pump 3.11 is connected with an alkali liquor storage tank 3.12 through a pipeline; a third pH measuring instrument 3.13 is also arranged on a pipeline connecting an alkali liquor inlet and a water inlet of the precooler 3.1, an alkali liquor inlet valve 3.14 is arranged at the alkali liquor inlet, the signal output end of the third pH measuring instrument 3.13 is in signal connection with the signal input end of the controller 1.11, and the signal output end of the controller 1.11 is in signal connection with the signal output end of the alkali liquor inlet valve 3.14; the pH value of the nitrate-rich brine passing through the membrane separation device 2 is low, the addition amount of alkali can be controlled according to a 3.13 signal of a third pH measuring instrument, and the pH value of the nitrate-rich brine is adjusted to be in an alkaline range so as to meet the requirement that the nitrate-rich brine is easier to crystallize in an alkaline environment;
the water outlet of the precooler 3.1 is connected with the water inlet of the crystallization tank 3.2 through a pipeline, the clear liquid outlet of the crystallization tank 3.2 is connected with the water inlet of the mother liquid circulating water pump 3.3 through a pipeline, the water outlet of the mother liquid circulating water pump 3.3 is connected with the water inlet of the mother liquid cooler 3.4 through a pipeline, the cold source inlet of the mother liquid cooler 3.4 is connected with the second circulating water supply pipeline, the cold source outlet of the mother liquid cooler 3.4 is connected with the second circulating water return pipeline, and cold water exchanges heat with mother liquid (clear liquid); the water outlet of the mother liquor cooler 3.4 is connected with the water inlet of the crystallization tank 3.2 through a first backflow pipeline, and clear liquid cooled by the mother liquor cooler 3.4 flows back to the crystallization tank 3.2; a third temperature sensor 3.15 is arranged on the first return pipeline, a second circulating water inlet valve 3.16 is arranged on the second circulating water supply pipeline, the signal output end of the third temperature sensor 3.15 is in signal connection with the signal input end of the controller 1.11, the signal output end of the controller 1.11 is in signal connection with the signal output end of the second circulating water inlet valve 3.16, and if the third temperature sensor 3.15 detects that the temperature of clear liquid in the water outlet of the mother liquid cooler 3.4 exceeds an allowable range, the second circulating water inlet valve 3.16 can be opened according to the signal of the third temperature sensor 3.15 to reduce the temperature of the clear liquid;
one part of clear liquid which is cooled by a mother liquid cooler 3.4 and then flows back to a crystallizing tank 3.2 is mixed with nitrate-rich brine in the crystallizing tank 3.2, the other part of clear liquid flows back to a precooler 3.1 through a second backflow pipeline between a clear liquid outlet of the crystallizing tank 3.2 and a water inlet of the precooler 3.1, partial cold energy of the clear liquid is recycled to the maximum extent, precooling and cooling are carried out, and the precooled nitrate-rich brine enters the crystallizing tank 3.2 again, so that the freezing energy consumption of the system is reduced; a fourth temperature sensor 3.17 is arranged on the second return pipeline, a clear liquid return valve 3.18 of the crystallization tank is also arranged on the second return pipeline, the signal output end of the fourth temperature sensor 3.17 is in signal connection with the signal input end of the controller 1.11, the signal output end of the controller 1.11 is in signal connection with the clear liquid return valve 3.18 of the crystallization tank, if the fourth temperature sensor 3.17 detects that the temperature of clear liquid in the water outlet of the precooler 3.1 exceeds the allowable range, the clear liquid return valve 3.18 of the crystallization tank can be controlled according to the signal of the fourth temperature sensor 3.17 to automatically adjust the supply amount of a cold source (clear liquid), and the precooling temperature is controlled;
after the freezing and denitration device 3 runs for a long time, the mother liquor cooler 3.4 can have certain pollution which is difficult to wash away, in order to ensure that the mother liquor cooler 3.4 continuously and stably runs, the water inlet of the mother liquor cooler 3.4 is connected with the water outlet of the flushing pump 3.19 through a pipeline, the water inlet of the flushing pump 3.19 is connected with the water outlet of the flushing liquid tank 3.20 through a pipeline, the water inlet of the flushing liquid tank 3.20 is connected with the lean nitrate water outlet of the membrane separation device 2 through a pipeline, when the light salt water membrane method denitration system stops running, the flushing state can be switched to be switched, the lean nitrate water is used for flushing the mother liquor cooler 3.4, and the flushing liquid after flushing returns to the pretreatment device 1, so that the mother liquor cooler 3.4 is prevented from being blocked by crystallization, and the denitration effect of the freezing and denitration device 3 is prevented from being influenced.
The clear liquid which is returned to the crystallization tank 3.2 after being cooled by the mother liquid cooler 3.4 is mixed with the nitrate-rich brine, the temperature in the crystallization tank 3.2 is ensured to be controlled below 5 ℃ all the time, the sodium sulfate in the nitrate-rich brine is saturated and separated out at low temperature, then crystal nuclei are continuously grown up by stirring to reach a certain volume to be precipitated, the crystallization outlet of the crystallization tank 3.2 is connected with the inlet of a crystal slurry pump 3.5 through a pipeline, the outlet of the crystal slurry pump 3.5 is connected with the inlet of a nitrate precipitation tank 3.6 through a pipeline, the crystal slurry at the bottom of the crystallization tank 3.2 is transferred into the nitrate precipitation tank 3.6 through the crystal slurry pump 3.5, the crystallization outlet of the nitrate precipitation tank 3.6 is connected with the inlet of a centrifuge 3.7 through a pipeline, sending the crystal slurry into a centrifuge 3.7 through a pipeline for solid-liquid separation to obtain a sodium sulfate decahydrate byproduct, wherein a crystallization outlet of the centrifuge 3.7 is connected with an inlet of a mirabilite storage tank 3.8 through a pipeline, and the sodium sulfate decahydrate byproduct enters the mirabilite storage tank 3.8; clear liquid outlets of the nitrate settling tank 3.6 and the centrifuge 3.7 are connected with a water inlet of a return water storage tank 3.9 through pipelines, a water outlet of the return water storage tank 3.9 is connected with a water inlet of a return water delivery pump 3.10 through pipelines, a water outlet of the return water delivery pump 3.10 is connected with a water inlet of the crystallization tank 3.2 through pipelines, clear liquid in the nitrate settling tank 3.6 and clear liquid of the centrifuge 3.7 are collected through the return water storage tank 3.9, clear liquid in the return water storage tank 3.9 is delivered to the crystallization tank 3.2 through the return water delivery pump 3.10, mother liquid after crystallization separation returns to the crystallization tank 3.2 to be continuously recycled, partial cold quantity of the clear liquid after crystallization is recycled to the greatest extent, freezing energy consumption of a system is reduced, and waste of energy consumption caused by discharging the clear liquid with low temperature to a salt melting process is avoided.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A membrane method denitration system for dilute brine is characterized by comprising a pretreatment device, a membrane separation device and a freezing denitration device; the water outlet of the fresh brine buffer tank of the pretreatment device is connected with the water inlet of the high-pressure pump of the membrane separation device through a pipeline, the nitrate-poor brine outlet of the nanofiltration membrane device of the membrane separation device is connected with the cold source inlet of the primary heat exchanger of the pretreatment device through a pipeline, and the cold source outlet of the primary heat exchanger of the pretreatment device is connected with the primary brine tank through a pipeline; and a nitrate-rich salt water outlet of a nanofiltration membrane device of the membrane separation device is connected with a water inlet of a precooler of the freezing denitrification device through a pipeline.
2. The system for denitration by a dilute brine membrane method as defined in claim 1, wherein the pretreatment device comprises a dilute brine storage tank, a dilute brine booster pump, a primary heat exchanger, a secondary heat exchanger, an activated carbon filter, a cartridge filter and a dilute brine buffer tank; a dechlorination light salt water pipeline is connected with a water inlet of the light salt water storage tank, and a water outlet of the light salt water storage tank is connected with a water inlet of the light salt water booster pump through a pipeline; a hydrochloric acid inlet and a sodium sulfite inlet are sequentially formed in a pipeline connecting a water outlet of the dilute brine storage tank and a water inlet of the dilute brine booster pump, the hydrochloric acid inlet is connected with a hydrochloric acid metering pump through a pipeline, the sodium sulfite inlet is connected with a sodium sulfite metering pump through a pipeline, the hydrochloric acid metering pump is connected with the hydrochloric acid storage tank through a pipeline, and the sodium sulfite metering pump is connected with the sodium sulfite storage tank through a pipeline; the water outlet of the dilute brine booster pump is connected with the water inlet of the primary heat exchanger through a pipeline, the water outlet of the primary heat exchanger is connected with the water inlet of the secondary heat exchanger through a pipeline, the cold source inlet of the secondary heat exchanger is connected with the first circulating water supply pipeline, and the cold source outlet of the secondary heat exchanger is connected with the first circulating water return pipeline; the water outlet of the secondary heat exchanger is connected with the water inlet of the activated carbon filter through a pipeline, the water outlet of the activated carbon filter is connected with the water inlet of the security filter through a pipeline, and the water outlet of the security filter is connected with the water inlet of the dilute brine buffer tank through a pipeline.
3. The membrane process denitration system for dilute brine according to claim 2, wherein a first ORP measuring instrument is arranged on the dechlorination dilute brine pipeline, a dilute brine storage tank bypass port is further arranged on the dechlorination dilute brine pipeline, the dilute brine storage tank bypass port is connected with the bypass pipeline, a dilute brine storage tank bypass valve is arranged at the dilute brine storage tank bypass port, a dilute brine storage tank water inlet valve is arranged at the dilute brine storage tank water inlet, a signal output end of the first ORP measuring instrument is in signal connection with a signal input end of a controller, and a signal output end of the controller is in signal connection with the dilute brine storage tank water inlet valve and a signal output end of the dilute brine storage tank bypass valve respectively.
4. The system of claim 3, wherein a first pH measuring instrument and a second ORP measuring instrument are arranged on a pipeline connecting the sodium sulfite inlet with a water inlet of the dilute brine booster pump, a hydrochloric acid inlet valve is arranged at the hydrochloric acid inlet, a sodium sulfite inlet valve is arranged at the sodium sulfite inlet, a signal output end of the first pH measuring instrument is in signal connection with a signal input end of the controller, and a signal output end of the controller is in signal connection with a signal output end of the hydrochloric acid inlet valve; and the signal output end of the second ORP measuring instrument is in signal connection with the signal input end of the controller, and the signal output end of the controller is in signal connection with the signal output end of the sodium sulfite inlet valve.
5. The system as claimed in claim 4, wherein a first temperature sensor is arranged on a pipeline connecting the water outlet of the secondary heat exchanger and the water inlet of the activated carbon filter, a first circulating water inlet valve is arranged on the first circulating water inlet pipeline, the signal output end of the first temperature sensor is in signal connection with the signal input end of the controller, and the signal output end of the controller is in signal connection with the signal output end of the first circulating water inlet valve.
6. The membrane method denitration system for light salt brine according to claim 5, wherein a third ORP measuring instrument, a second pH measuring instrument and a second temperature sensor are arranged on a pipeline connecting the water outlet of the activated carbon filter and the water inlet of the security filter, an activated carbon filter bypass port is further formed on a pipeline connecting the water outlet of the activated carbon filter and the water inlet of the security filter, the activated carbon filter bypass port is connected with a bypass pipeline, and an activated carbon filter bypass valve is installed at the activated carbon filter bypass port; the water inlet of the security filter is provided with a water inlet valve of the security filter, the signal output ends of the third ORP measuring instrument, the second pH measuring instrument and the second temperature sensor are respectively in signal connection with the signal input end of the controller, and the signal output end of the controller is respectively in signal connection with the water inlet valve of the security filter and the bypass valve of the activated carbon filter.
7. The membrane method denitration system for dilute brine according to claim 1, wherein the membrane separation device comprises a high-pressure pump and a nanofiltration membrane device, and a water outlet of the high-pressure pump is connected with a water inlet of the nanofiltration membrane device through a pipeline; an anti-backpressure valve is arranged at a nitrate-poor brine outlet of the nanofiltration membrane device; the water inlet of the high-pressure pump is connected with the water outlet of the cleaning filter through a pipeline, the water inlet of the cleaning filter is connected with the water outlet of the cleaning pump through a pipeline, and the water inlet of the cleaning pump is connected with the water outlet of the cleaning water tank through a pipeline.
8. The membrane-method denitration system for dilute brine according to claim 6, wherein the freezing denitration device comprises a precooler, a crystallization tank, a mother liquor circulating water pump, a mother liquor cooler, a crystal slurry pump, a nitrate precipitation tank, a centrifuge, a mirabilite storage tank, a backwater storage tank and a backwater delivery pump; an alkali liquor inlet is formed in a pipeline connecting a nitrate-rich water outlet of the nanofiltration membrane device and a water inlet of the precooler, the alkali liquor inlet is connected with an alkali metering pump through a pipeline, and the alkali metering pump is connected with an alkali liquor storage tank through a pipeline; the water outlet of the precooler is connected with the water inlet of the crystallization tank through a pipeline, the clear liquid outlet of the crystallization tank is connected with the water inlet of the mother liquid circulating water pump through a pipeline, the water outlet of the mother liquid circulating water pump is connected with the water inlet of the mother liquid cooler through a pipeline, and the water outlet of the mother liquid cooler is connected with the water inlet of the crystallization tank through a first backflow pipeline; a clear liquid outlet of the crystallization tank is connected with a water inlet of the precooler through a second backflow pipeline; a cold source inlet of the mother liquor cooler is connected with a second circulating water supply pipeline, and a cold source outlet of the mother liquor cooler is connected with a second circulating water return pipeline;
the water inlet of the mother liquor cooler is connected with the water outlet of a flushing pump through a pipeline, the water inlet of the flushing pump is connected with the water outlet of a flushing liquid tank through a pipeline, and the water inlet of the flushing liquid tank is connected with the nitrate-poor water outlet of the membrane separation device through a pipeline;
the crystallization outlet of crystallization tank with the import of magma pump passes through the pipeline and links to each other, the export of magma pump with the import of depositing the nitre groove passes through the pipeline and links to each other, the crystallization outlet of depositing the nitre groove with centrifuge's import passes through the pipeline and links to each other, centrifuge's crystallization outlet with the import of mirabilite storage tank passes through the pipeline and links to each other, deposit the nitre groove with centrifuge's clear solution export all with the water inlet of return water storage tank passes through the pipeline and links to each other, the delivery port of return water storage tank with the water inlet of return water delivery pump passes through the pipeline and links to each other, the delivery port of return water delivery pump with the water inlet of crystallization tank passes through the pipeline and links to each other.
9. The membrane-method denitration system for weak brine according to claim 8, wherein a third pH measuring instrument is arranged on a pipeline connecting the alkali liquor inlet and the water inlet of the precooler, an alkali liquor inlet valve is installed at the alkali liquor inlet, a signal output end of the third pH measuring instrument is in signal connection with a signal input end of the controller, and a signal output end of the controller is in signal connection with a signal output end of the alkali liquor inlet valve.
10. The membrane method denitration system for light salt brine as defined in claim 9, wherein a third temperature sensor is provided on the first return line, a second circulation water inlet valve is provided on the second circulation water inlet line, a signal output terminal of the third temperature sensor is in signal connection with a signal input terminal of the controller, and a signal output terminal of the controller is in signal connection with a signal output terminal of the second circulation water inlet valve; the second return pipeline is provided with a fourth temperature sensor, the second return pipeline is also provided with a clear liquid return valve of the crystallization tank, the signal output end of the fourth temperature sensor is in signal connection with the signal input end of the controller, and the signal output end of the controller is in signal connection with the clear liquid return valve of the crystallization tank.
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| CN202122282614.1U CN215947029U (en) | 2021-09-18 | 2021-09-18 | Light salt brine embrane method deNOx systems |
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| CN202122282614.1U CN215947029U (en) | 2021-09-18 | 2021-09-18 | Light salt brine embrane method deNOx systems |
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