CN108178240B - Method for regenerating desalting mixed bed - Google Patents
Method for regenerating desalting mixed bed Download PDFInfo
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- CN108178240B CN108178240B CN201810040581.XA CN201810040581A CN108178240B CN 108178240 B CN108178240 B CN 108178240B CN 201810040581 A CN201810040581 A CN 201810040581A CN 108178240 B CN108178240 B CN 108178240B
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- mixed bed
- resin
- water
- exchange resin
- bed tank
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- 238000000034 method Methods 0.000 title claims abstract description 60
- 230000001172 regenerating effect Effects 0.000 title claims abstract description 11
- 238000011033 desalting Methods 0.000 title abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 136
- 239000011347 resin Substances 0.000 claims abstract description 96
- 229920005989 resin Polymers 0.000 claims abstract description 96
- 239000007788 liquid Substances 0.000 claims abstract description 74
- 238000011069 regeneration method Methods 0.000 claims abstract description 48
- 230000008929 regeneration Effects 0.000 claims abstract description 46
- 238000011001 backwashing Methods 0.000 claims abstract description 44
- 238000005406 washing Methods 0.000 claims abstract description 41
- 239000003513 alkali Substances 0.000 claims abstract description 40
- 239000002253 acid Substances 0.000 claims abstract description 38
- 230000000694 effects Effects 0.000 claims abstract description 23
- 239000003957 anion exchange resin Substances 0.000 claims description 50
- 239000003729 cation exchange resin Substances 0.000 claims description 49
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims description 46
- 239000008367 deionised water Substances 0.000 claims description 19
- 229910021641 deionized water Inorganic materials 0.000 claims description 19
- 238000002156 mixing Methods 0.000 claims description 11
- 239000004519 grease Substances 0.000 claims description 9
- 238000005507 spraying Methods 0.000 claims description 6
- 230000007935 neutral effect Effects 0.000 claims description 5
- 238000010612 desalination reaction Methods 0.000 claims description 2
- 150000002500 ions Chemical class 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 10
- 238000002347 injection Methods 0.000 abstract description 6
- 239000007924 injection Substances 0.000 abstract description 6
- 239000000126 substance Substances 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 21
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 8
- 150000001450 anions Chemical class 0.000 description 8
- 150000001768 cations Chemical class 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- -1 salt ions Chemical class 0.000 description 4
- 229910001415 sodium ion Inorganic materials 0.000 description 4
- 239000002585 base Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 238000004062 sedimentation Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M sodium chloride Inorganic materials [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 229940023913 cation exchange resins Drugs 0.000 description 2
- 239000013505 freshwater Substances 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- 239000007832 Na2SO4 Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- UIIMBOGNXHQVGW-UHFFFAOYSA-M sodium bicarbonate Substances [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 238000013517 stratification Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
- B01J49/05—Regeneration or reactivation of ion-exchangers; Apparatus therefor of fixed beds
- B01J49/09—Regeneration or reactivation of ion-exchangers; Apparatus therefor of fixed beds of mixed beds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
- B01J49/50—Regeneration or reactivation of ion-exchangers; Apparatus therefor characterised by the regeneration reagents
- B01J49/53—Regeneration or reactivation of ion-exchangers; Apparatus therefor characterised by the regeneration reagents for cationic exchangers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
- B01J49/50—Regeneration or reactivation of ion-exchangers; Apparatus therefor characterised by the regeneration reagents
- B01J49/57—Regeneration or reactivation of ion-exchangers; Apparatus therefor characterised by the regeneration reagents for anionic exchangers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
- B01J49/60—Cleaning or rinsing ion-exchange beds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
- C02F2001/427—Treatment of water, waste water, or sewage by ion-exchange using mixed beds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/16—Regeneration of sorbents, filters
Abstract
The invention relates to the field of chemical water production of power plants, and discloses a method for regenerating a desalting mixed bed. According to the method, before the resin layer is subjected to hydraulic backwashing layering, the liquid level in the mixed bed tank is reduced to submerge the top of the resin layer, and compressed air is introduced into the mixed bed tank for air washing, so that the resin can be effectively loosened, the water injection pressure in the subsequent backwashing step is reduced, the backwashing layering effect is enhanced, the backwashing layering time is obviously shortened, and the backwashing water consumption in the resin backwashing layering process is reduced. And after the resin is backwashed by using water, the concentration and the flow of the regenerated acid liquid and the regenerated alkali liquid are controlled, so that the consumption of the regenerated acid liquid and the regenerated alkali liquid in the resin regeneration process can be obviously reduced, and the regeneration time of the desalting mixed bed is greatly shortened. The water produced by the desalting mixed bed in a single period is high, and the water produced by the regenerated desalting mixed bed is excellent in quality.
Description
Technical Field
The invention relates to the field of chemical water production of power plants, in particular to a method for regenerating a desalting mixed bed.
Background
The demineralized water is mainly used for preparing pure water for boilers, particularly, the requirements of dry quenching boilers on water quality are high, most of demineralized water treatment processes all over the country are reverse osmosis/mixed bed composite treatment systems, the quality of water supplied by the demineralized water system directly influences the normal production of the dry quenching boilers and steam turbines, and inestimable loss is caused to enterprise production due to slight negligence. Wherein, the mixed bed is the last control procedure of the process of the demineralized water system, and the resin layering process of the boiler make-up water desalting mixed bed of the power plant generally adopts hydraulic backwashing layering: namely, backwashing is carried out from bottom to top through water power, and the aim of layering is achieved by automatically falling down from the bed through density difference of the anion resin and the cation resin in the mixed bed. It can remove various anions and cations in water, so that the conductivity of the effluent is controlled below 0.2 mu s/cm, and the water requirement of a dry quenching system is met. In the operation process of the mixed bed, after the mixed bed is operated for a certain period (generally 15-30 days, related to the water supply), resin exchange is saturated, and the anion resin and the cation resin need to be regenerated. The regeneration work is one of the important operations of the mixed bed operation, the regeneration mainly comprises the steps of respectively flushing cation resin and anion resin by using acid and alkali with proper concentration at a specified flow rate, and removing anions and cations adsorbed on the resin after the cation and anion resin is flushed for a certain time so as to achieve the purpose of recycling the mixed bed, the regeneration progress degree of the cation and anion resin has direct influence on the work exchange capacity and the water quality of water supply during the later water production operation, and the quality of the regeneration work also directly relates to the water production economy. Therefore, the mixed bed regeneration operation plays an important role in the stable operation of the water quality of the supplied water and the demineralized water system. However, during the operation, there are several problems as follows:
1. the existing hydraulic backwashing layering effect is poor, the regeneration effect is seriously influenced, and the water production resistivity can not meet the requirements of regeneration and water supply generally;
2. the traditional regeneration layering process has the advantages that the resin backwashing layering time is long, the water inflow is large, desalted water is wasted, and the regenerated alkali consumption is large.
The regeneration effect and the acid-base consumption of the resin are directly influenced by the regeneration backwashing layering process. Therefore, it is necessary to optimize the mixed bed regeneration process according to the actual situation.
Disclosure of Invention
The invention aims to overcome the defects of poor hydraulic backwashing layering effect, long resin backwashing layering time, large water inflow, desalted water waste, large regenerated alkali consumption and the like of the traditional regeneration layering process, and provides a desalting mixed bed regeneration method.
In order to achieve the above object, the present invention provides, in one aspect, a method for regenerating a mixed bed for desalination, the method comprising the steps of:
(1) reducing water level and loosening resin: reducing the liquid level height in the mixed bed tank to 1/8-1/6 exceeding the liquid level height at the top end of the resin layer, introducing compressed air into the mixed bed tank, and continuously performing air washing for 10-15 minutes;
(2) resin layering: introducing backwash water into the mixed bed tank, controlling the introduction flow of the backwash water to be 60-70t/h, adjusting the introduction flow of the backwash water to be 20-30t/h at the speed of reducing the introduction flow of the backwash water by 3-4t/h per minute when the liquid level at the top end of the resin layer expands to the visible range of an upper observation window of the mixed bed tank, continuously backwashing for 15-25 minutes, gradually closing the inflow of the backwash water, and confirming the layering effect of the anion exchange resin and the cation exchange resin;
(3) resin regeneration: pre-spraying deionized water into the mixed bed tank, adjusting the concentration and flow rate of introduced regenerated acid liquid and regenerated alkali liquid, controlling the concentration of the regenerated acid liquid to be 3.5-4 wt%, the introduction flow rate to be 12-18t/h, the concentration of the regenerated alkali liquid to be 3.5-4 wt%, and the introduction flow rate to be 12-18t/h, so as to regenerate anion exchange resin and cation exchange resin;
(4) and (3) replacement: keeping the flow of the deionized water introduced in the step (3), stopping introducing the regenerated acid liquid and the regenerated alkali liquid, and replacing the regenerated anion exchange resin and the regenerated cation exchange resin until the drainage is neutral or the conductivity is not more than 5 mu S/cm;
(5) mixing the grease: introducing compressed air into the mixed bed tank to uniformly mix the anion exchange resin and the cation exchange resin, wherein the introduction time is 3-10 minutes;
(6) quickly falling to a bed: after the mixing of the grease is finished, controlling the drainage flow to be 80-100t/h, and enabling the anion exchange resin and the cation exchange resin which are uniformly mixed to quickly fall into the bed for 1-3 minutes;
(7) washing in a normal way: and (3) introducing forward washing water into the mixed bed tank, and controlling the introduction flow rate of the forward washing water to be 80-100t/h after the mixed bed tank is filled with the forward washing water until the conductivity of the washing water is not more than 0.15 mu S/cm.
The inventor of the invention discovers through intensive research that in the process of regenerating a desalting mixed bed, before the resin layer is subjected to hydraulic backwashing layering, the liquid level in the mixed bed tank is reduced to 1/8-1/6 which exceeds the liquid level height of the top end of the resin layer, compressed air is introduced into the mixed bed tank for air washing, so that the resin can be effectively loosened, the water injection pressure in the subsequent backwashing step is reduced, the backwashing layering effect is enhanced, the backwashing layering time is obviously shortened, and the backwashing water consumption is reduced. And after the resin is backwashed by using water, the concentration and the flow of the regenerated acid liquid and the regenerated alkali liquid are controlled, so that the consumption of the regenerated acid liquid and the regenerated alkali liquid in the resin regeneration process can be obviously reduced, and the regeneration time of the desalting mixed bed is greatly shortened. The water produced by the desalting mixed bed in a single period is high, and the water produced by the regenerated desalting mixed bed is excellent in quality.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The invention provides a method for regenerating a desalting mixed bed, which comprises the following steps:
(1) reducing water level and loosening resin: reducing the liquid level height in the mixed bed tank to 1/8-1/6 exceeding the liquid level height at the top end of the resin layer, introducing compressed air into the mixed bed tank, and continuously performing air washing for 10-15 minutes;
(2) resin layering: introducing backwash water into the mixed bed tank, controlling the introduction flow of the backwash water to be 60-70t/h, adjusting the introduction flow of the backwash water to be 20-30t/h at the speed of reducing the introduction flow of the backwash water by 3-4t/h per minute when the liquid level at the top end of the resin layer expands to the visible range of an upper observation window of the mixed bed tank, continuously backwashing for 15-25 minutes, gradually closing the inflow of the backwash water, and confirming the layering effect of the anion exchange resin and the cation exchange resin;
(3) resin regeneration: pre-spraying deionized water into the mixed bed tank, adjusting the concentration and flow rate of introduced regenerated acid liquid and regenerated alkali liquid, controlling the concentration of the regenerated acid liquid to be 3.5-4 wt%, the introduction flow rate to be 12-18t/h, the concentration of the regenerated alkali liquid to be 3.5-4 wt%, and the introduction flow rate to be 12-18t/h, so as to regenerate anion exchange resin and cation exchange resin;
(4) and (3) replacement: stopping introducing the regenerated acid solution and the regenerated alkali solution, introducing deionized water for replacing the anion exchange resin and the cation exchange resin, wherein the introduction flow rate of the deionized water is 12-18t/h, and the discharge water is neutral or the conductivity is not more than 5 mu S/cm;
(5) mixing the grease: introducing compressed air into the mixed bed tank to uniformly mix the anion exchange resin and the cation exchange resin, wherein the introduction time is 3-10 minutes;
(6) quickly falling to a bed: after the mixing of the grease is finished, controlling the drainage flow to be 80-100t/h, and enabling the anion exchange resin and the cation exchange resin which are uniformly mixed to quickly fall into the bed for 1-3 minutes;
(7) washing in a normal way: and (3) introducing forward washing water into the mixed bed tank, and controlling the introduction flow rate of the forward washing water to be 80-100t/h after the mixed bed tank is filled with the forward washing water until the conductivity of the washing water is not more than 0.15 mu S/cm.
According to the invention, in the step (1), the specific process of loosening the mixed bed resin may include: and opening an exhaust valve and a forward washing drain valve of the mixed bed tank, closing the exhaust valve and the forward washing drain valve of the mixed bed tank when the liquid level in the mixed bed tank is reduced to 1/8-1/6 exceeding the liquid level height of the top end of the resin layer, opening a compressed air inlet valve of the mixed bed tank, introducing compressed air, and continuously performing air washing for 10-15 minutes to loosen the resin in the mixed bed tank.
According to the invention, water is discharged in advance before compressed air is introduced, so that the liquid level in the mixed bed tank is reduced to 1/8-1/6 exceeding the liquid level height of the top end of the resin layer, the injection pressure head of the compressed air can be effectively reduced, the loosening effect of the resin is not influenced, the compressed air is introduced at lower pressure, and the gap between the anion exchange resin and the cation exchange resin can be remarkably increased.
In the present invention, the head refers to a velocity head that the fluid has due to the flow velocity when flowing.
According to a specific embodiment of the invention, in the step (1), the height of the mixed bed tank is 2.50 meters, the inner diameter is 2.20 meters, and after the liquid level height in the mixed bed tank is reduced to be 15-20cm higher than the liquid level height at the top end of the resin layer, compressed air is introduced to significantly reduce the pressure required by the subsequent introduction of backwash water.
According to a specific embodiment of the invention, in the step (1), during the process of introducing the compressed air into the mixed bed tank, the pressure of the compressed air can be 0.5-0.7MPa, and the introduction flow rate is 10-15m3/(m2S), the space between the anion exchange resin and the cation exchange resin can be effectively increased.
According to the invention, in the step (2), the process of introducing the backwash water into the mixed bed tank comprises the following steps: and (3) after the process of introducing the compressed air in the step (1) is finished, introducing backwashing water into the mixed bed tank when the resin begins to descend.
According to the present invention, in the step (2), the specific process of resin delamination may include: and (2) after the gas washing in the step (1) is finished, loosening the resin in the mixed bed tank, closing a compression air inlet valve of the mixed bed tank, opening a backwashing water inlet valve of the mixed bed tank, introducing backwashing water, adjusting the opening degree of the backwashing water inlet valve, controlling the introduction flow of the backwashing water to be 60-70t/h, gradually adjusting the introduction flow of the backwashing water to be 20-30t/h at the rate of reducing the introduction flow of the backwashing water per minute by 3-4t/h after the liquid level at the top end of the resin layer is expanded to the range of an observation window at the upper part of the mixed bed tank, and continuously backwashing for 15-25 minutes until the anion exchange resin and the cation exchange resin are layered. Because the gap between the anion exchange resin and the cation exchange resin is smaller at the initial stage of backwashing, in order to enhance the backwashing effect, the resin is fully expanded, the contact area between backwash water flowing through the resin layer from bottom to top and the resin is increased to the maximum extent, the required backwashing pressure head is higher, the backwash water flow is larger, and the required backwashing water flow needs to reach 60-70 t/h; after the resin is fully expanded, the anion exchange resin and the cation exchange resin begin to automatically settle and fall down, the flow rate of backwashing water can be slowly reduced, the flow rate of the backwashing water is gradually adjusted to 20-30t/h at the rate that the flow rate of the backwashing water per minute is reduced by 3-4t/h, backwashing is continuously carried out for 15-25 minutes, at the later stage of backwashing, in the process of falling down the resin, the density of the anion exchange resin and the density of the cation exchange resin are different, the density of the cation exchange resin is higher, the density of the anion exchange resin is lower, after the anion exchange resin and the cation exchange resin are gradually settled, and in the flow range of the backwashing water controlled by the invention, a remarkable resin layering effect can be obtained.
According to a specific embodiment of the invention, in the step (2), the time for adjusting the flow rate of the backwash water from 60-70t/h to 20-30t/h can be 10-20 minutes, which is beneficial to keeping the injection pressure head of the backwash water uniformly reduced and not influencing the sedimentation rate of the anion exchange resin and the cation exchange resin.
According to the present invention, the density arrangement order of the cation exchange resins for different cation types is as follows:
H+＜NH4 +＜Ca2+＜Na+＜K+
the order of density arrangement for the anion exchange resins of different anion types is as follows:
OH-＜Cl-＜CO3 2-＜HCO3 -＜NO3 -＜SO4 2-
in general, the resin layering effect of the conventional desalting mixed bed regeneration method is not good, and in order to further enhance the resin layering effect, the resin layering process in the conventional method further comprises the following steps: and after backwash water is introduced into the mixed bed tank, diluted alkali liquor is introduced into the mixed bed tank, so that the cation exchange resin is fully converted into Na-ion type anion exchange resin, and the anion exchange resin is fully converted into OH-ion type anion exchange resin, thereby increasing the density difference of the cation exchange resin, increasing the sedimentation speed of the cation exchange resin, reducing the sedimentation speed of the anion exchange resin and improving the layering effect. However, by the method provided by the invention, before the resin layer is subjected to hydraulic backwashing layering, the liquid level in the mixed bed tank is reduced to 1/8-1/6 exceeding the liquid level height of the top end of the resin layer, and then compressed air is introduced into the mixed bed tank for air washing, so that the resin can be effectively loosened, the water injection pressure in the subsequent backwashing step is reduced, the backwashing layering effect is enhanced, the resin layering effect can be directly obvious, and the step of introducing diluted alkali liquor in the traditional process can be completely omitted.
According to the present invention, the specific process of regenerating the resin of step (3) may include: firstly, opening a water inlet valve of a regenerated acid liquid ejector and a water inlet valve of a regenerated alkali liquid ejector of a mixed bed tank, starting a deionized water pump, pre-ejecting deionized water, controlling the opening degrees of the water inlet valve of the regenerated acid liquid ejector and the water inlet valve of the regenerated alkali liquid ejector, keeping the flow rate of the deionized water at 12-18t/h, then opening an acid outlet pneumatic door of a regenerated acid liquid metering box and an alkali outlet pneumatic door of a regenerated alkali liquid metering box of the mixed bed tank, introducing regenerated acid liquid and regenerated alkali liquid into the mixed bed tank, controlling the concentration of the regenerated acid liquid at 3.5-4 wt%, and introducing the flow rate at 12-18t/h, the concentration of the regenerated alkali liquor is 3.5-4 wt%, the flow rate is 12-18t/h, the liquid level in the mixed bed tank is kept within the range of an observation window at the upper part of the mixed bed tank, and when the liquid level in the mixed bed tank is kept constant, the anion exchange resin and the cation exchange resin are regenerated.
According to the invention, in step (3), the process of regenerating the resin further comprises: and (3) after the anion exchange resin and the cation exchange resin are layered in the step (2), reducing the liquid level height in the mixed bed tank to 1/24-1/12 exceeding the liquid level height at the top end of the resin layer, and pre-spraying deionized water into the mixed bed tank by passing through an ion water pump.
According to a specific embodiment of the invention, in the step (3), the height of the mixed bed tank is 2.50 meters, the inner diameter is 2.20 meters, after the anion exchange resin and the cation exchange resin are layered in the step (2), the liquid level in the mixed bed tank is reduced to be 5-10cm higher than the liquid level at the top end of the resin layer, and then the deionized water is pre-sprayed into the mixed bed tank by a deionized water pump.
According to the invention, in the resin regeneration process in the step (3), when the regeneration acid solution and the regeneration alkali solution are introduced into the mixed bed tank, the concentration of the regeneration acid solution and the concentration of the regeneration alkali solution are both preferably 3.5-4 wt%, and the introduction flow rate of the regeneration acid solution and the regeneration alkali solution is both preferably 14-16t/h (for example 15 t/h). Therefore, the time consumed by resin regeneration can be obviously shortened, and the fresh water consumption in the subsequent desalting step can be greatly saved. If the concentration of the regenerated acid solution and the regenerated alkali solution is lower than 3.5 weight percent, the regeneration effect of the resin is influenced, and the running period of the regenerated resin is obviously reduced; if the concentration of the regenerated acid solution and the regenerated alkali solution is higher than 4 wt%, the regeneration effect of the resin is not affected, but the regeneration time of the resin is increased, and the fresh water consumption in the subsequent replacement step is increased.
According to the invention, in the step (3), the time for introducing the regeneration acid solution and the regeneration alkali solution into the mixed bed tank is preferably 35 to 45 minutes (for example, 40 minutes), so that sufficient time can be provided for fully reacting and regenerating the anion exchange resin and the cation exchange resin.
According to the invention, in step (3), ion exchange takes place during the regeneration of the resin, the ion exchange reaction being of the formula:
cation exchange resin reaction of R-Na++H+→R-H++Na+
Anion exchange resin reaction R-Cl-+OH-→R-OH-+Cl-
According to the invention, in step (3), HCl or H may be used for the strongly acidic cation exchange resin2SO4NaCl and Na2SO4Regenerating an aqueous solution (regenerated acid solution) of at least one of the above; for weakly acidic cation exchange resins HCl or H may be used2SO4Regenerating the aqueous solution (regenerated acid solution); for the strong-base anion exchange resin, NaOH or NaCl aqueous solution (regeneration alkali liquor) can be used for regeneration; for weak base anion exchange resin, NaOH and Na can be used2CO3And NaHCO3An aqueous solution (regeneration lye) of at least one of them.
According to the invention, in order to avoid the influence of the existence of salt ions on the effect of the regenerated resin, the salt ions generated in the resin regeneration process in the step (3) should be removed in time, so the regeneration process of the desalting mixed bed also comprises the replacement operation in the step (4), and the specific process of the replacement operation can comprise: stopping introducing the regenerated acid solution and the regenerated alkali solution, introducing deionized water to replace the regenerated anion exchange resin and the regenerated cation exchange resin, and keeping the introduction flow (namely 12-18t/h) of the regenerated acid solution and the regenerated alkali solution in the step (3) to respectively clean the regenerated anion exchange resin and the regenerated cation exchange resin layer by the deionized water until the drainage is neutral or the conductivity is not more than 5 mu S/cm and the surface salt ions are completely removed.
According to the invention, in step (4), the replacement time is preferably 40 to 50 minutes (for example 45 minutes), which ensures maximum removal of the salt ions.
According to the invention, the layered resin must be mixed uniformly again before the regenerated resin is put into operation, and the anion exchange resin and the cation exchange resin are usually stirred and mixed by introducing compressed air from the bottom of the resin layer. In the step (5), the specific process of mixing the grease may include: and opening a compressed air inlet valve of the mixed bed tank, and introducing compressed air into the mixed bed tank to uniformly mix the anion exchange resin and the cation exchange resin.
According to a specific embodiment of the invention, in the step (5), during the process of introducing the compressed air into the mixed bed tank, the pressure of the compressed air is preferably 0.5-0.7MPa, and the introduction flow rate is 10-15m3/(m2S), the time of introduction is preferably 5 to 10 minutes, so that the regenerated anion exchange resin and cation exchange resin are mixed uniformly without abrading the resins.
According to the invention, after the fat mixing in the step (5) is finished, the anion exchange resin and the cation exchange resin which are uniformly mixed need to be rapidly fallen into the bed, and the specific process of the rapid falling bed can comprise: closing the compressed air valve, opening the forward washing drain valve, adjusting the opening degree to the maximum, and controlling the drain flow to be 80-100t/h so as to enable the uniformly mixed anion exchange resin and cation exchange resin to quickly fall into the bed, wherein the falling time is preferably 1-3 minutes (for example 2 minutes). Therefore, the phenomenon that the anion exchange resin and the cation exchange resin which are uniformly mixed in the step (5) are delaminated again due to too low falling bed speed and the fat mixing effect is influenced can be effectively prevented.
According to the invention, the resin falling from the bed in the step (6) is subjected to a forward washing before the regenerated and uniformly mixed resin is used for water production. In the step (7), the specific process of the normal washing may include: and opening a forward washing water inlet valve and a forward washing water outlet valve of the mixed bed tank, introducing forward washing water into the mixed bed tank, and controlling the introduction flow rate of the forward washing water to be 80-100t/h until the conductivity of the washing water is not more than 0.15 mu S/cm, so that the excellent and stable quality of the effluent can be ensured.
According to the invention, in the step (7), the forward washing water is preferably introduced into the mixed bed tank for 15-30 minutes, so that the exchange of the residual regenerated acid liquid, regenerated alkali liquid and regenerated product in the resin and the mixed resin can be effectively prevented, and the influence of the residual regenerated acid liquid, regenerated alkali liquid and regenerated product on the quality of the effluent water can be further reduced.
The present invention will be described in detail below by way of examples.
In the following examples, the height of the mixed bed tank was 2.50 m, the inner diameter was 2.20 m, and the anion exchange resin was strongly basic anion exchange resin, model number was 201 × 7 MB; the cation exchange resin is strong acid cation exchange resin with a model of 001 × 7 MB.
In the following examples, the conductivity of the effluent was measured using a conductivity meter model UDA2182, manufactured by HONEYWELL corporation.
In the following examples, one cycle of regeneration of the mixed bed for desalting was 30 days.
Examples 1 to 4 and comparative examples 1 to 4
(1) Reducing water level and loosening resin: reducing the liquid level height in the mixed bed tank, introducing compressed air into the mixed bed tank, and carrying out continuous air washing;
(2) resin layering: introducing backwash water into the mixed bed tank, gradually reducing the injection flow of the backwash water when the liquid level at the top end of the resin layer expands to the range of an observation window at the upper part of the mixed bed tank, gradually closing the inflow of the backwash water, and confirming the layering effect of the anion exchange resin and the cation exchange resin;
(3) resin regeneration: pre-spraying deionized water into the mixed bed tank, adjusting the concentration and flow of introduced regenerated acid liquid and regenerated alkali liquid, and introducing the regenerated acid liquid and the regenerated alkali liquid into the mixed bed tank to regenerate the anion exchange resin and the cation exchange resin;
(4) and (3) replacement: introducing deionized water into the mixed bed tank until the drainage is neutral or the conductivity is not more than 5 mu S/cm;
(5) mixing the grease: introducing compressed air into the mixed bed tank to uniformly mix the anion exchange resin and the cation exchange resin;
(6) quickly falling to a bed: after mixing the grease, opening a forward washing drain valve, and quickly adjusting the opening of the forward washing drain valve to the maximum to quickly fall the regenerated resin into a bed;
(7) washing in a normal way: and introducing forward washing water into the mixed bed tank until the conductivity of the washing water is not more than 0.15 mu S/cm.
In each of the examples and comparative examples, the operational parameters of each step are shown in Table 1.
Test example
The water production per cycle, the acid liquor consumption per cycle, the alkali liquor consumption per cycle, the water consumption per cycle for backwash stratification (t) and the time required for each regeneration of the mixed bed after regeneration according to the methods of examples 1 to 4 and comparative examples 1 to 4 were respectively tested, and the test results are shown in table 2.
TABLE 1
TABLE 2
As can be seen from the results in Table 2, the method provided by the invention has the advantages of good economy, strong practicability, simple and controllable operation and the like. The method provided by the invention has the advantages that the resin layering effect is obvious in the regeneration process of the desalting mixed bed, the consumption of the regenerated acid liquid and the regenerated alkali liquid in the resin regeneration process and the water consumption in the resin backwashing layering process can be obviously reduced, and meanwhile, the regeneration time of the desalting mixed bed is greatly shortened. And the regenerated resin has good quality, the single period of the desalting mixed bed has high water production quantity, and the effluent quality of the regenerated desalting mixed bed is excellent.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (9)
1. A method of regenerating a mixed bed for desalination, the method comprising the steps of:
(1) reducing water level and loosening resin: reducing the liquid level height in the mixed bed tank to be 15-19cm higher than the liquid level height at the top end of the resin layer, introducing compressed air into the mixed bed tank, and continuously performing air washing for 10-15 minutes;
(2) resin layering: introducing backwash water into the mixed bed tank, controlling the introduction flow of the backwash water to be 60-65t/h, adjusting the introduction flow of the backwash water to be 20-30t/h at the speed of reducing the introduction flow of the backwash water by 3-4t/h per minute when the liquid level at the top end of the resin layer expands to the visible range of an upper observation window of the mixed bed tank, continuously backwashing for 15-25 minutes, gradually closing the inflow of the backwash water, and confirming the layering effect of the anion exchange resin and the cation exchange resin;
(3) resin regeneration: pre-spraying deionized water into the mixed bed tank, adjusting the concentration and flow rate of introduced regenerated acid liquid and regenerated alkali liquid, controlling the concentration of the regenerated acid liquid to be 3.5-3.8 wt%, the introduction flow rate to be 12-18t/h, the concentration of the regenerated alkali liquid to be 3.5-3.8 wt%, and the introduction flow rate to be 12-18t/h, so as to regenerate anion exchange resin and cation exchange resin;
(4) and (3) replacement: keeping the flow of the deionized water introduced in the step (3), stopping introducing the regenerated acid liquid and the regenerated alkali liquid, and replacing the regenerated anion exchange resin and the regenerated cation exchange resin until the drainage is neutral or the conductivity is not more than 5 mu S/cm;
(5) mixing the grease: introducing compressed air into the mixed bed tank to uniformly mix the anion exchange resin and the cation exchange resin, wherein the introduction time is 3-10 minutes;
(6) quickly falling to a bed: after the mixing of the grease is finished, controlling the drainage flow to be 80-100t/h, and enabling the anion exchange resin and the cation exchange resin which are uniformly mixed to quickly fall into the bed for 1-3 minutes;
(7) washing in a normal way: and (3) introducing forward washing water into the mixed bed tank, and controlling the introduction flow rate of the forward washing water to be 80-100t/h after the mixed bed tank is filled with the forward washing water until the conductivity of the washing water is not more than 0.15 mu S/cm.
2. The method according to claim 1, wherein in the step (1), the pressure of the compressed air is 0.5-0.7MPa, and the flow rate of the compressed air is 10-15m during the process of introducing the compressed air into the mixed bed tank3/(m2·S)。
3. The method according to claim 1, wherein in the step (2), the time for adjusting the flow rate of the backwash water from 60 to 65t/h to 20 to 30t/h is 10 to 20 minutes.
4. The method according to claim 1, wherein in the step (2), the step of introducing the backwash water into the mixed bed tank comprises: and (3) after the process of introducing the compressed air in the step (1) is finished, introducing backwashing water into the mixed bed tank when the resin begins to descend.
5. The method of claim 1, wherein in step (3), the resin regeneration process further comprises: and (3) after the anion exchange resin and the cation exchange resin are layered in the step (2), reducing the liquid level height in the mixed bed tank to 1/24-1/12 exceeding the liquid level height at the top end of the resin layer, and pre-spraying deionized water into the mixed bed tank by passing through an ion water pump.
6. The method as claimed in claim 1, wherein in the step (3), the flow rates of the regenerated acid solution and the regenerated alkali solution in the mixed bed tank are 14-16t/h and the flow time is 35-45 minutes.
7. The method as claimed in claim 1, wherein the deionized water is introduced for 40-50 minutes in the step (4).
8. The method according to claim 1, wherein in the step (5), the pressure of the compressed air is 0.5-0.7MPa, and the flow rate of the compressed air is 10-15m during the process of introducing the compressed air into the mixed bed tank3/(m2S) for 5 to 10 minutes.
9. The method according to claim 1, wherein in the step (7), the forward washing water is introduced into the mixed bed tank for 15 to 30 minutes.
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| CN108704674A (en) * | 2018-06-30 | 2018-10-26 | 神华国华广投（柳州）发电有限责任公司 | A kind of highly efficient regeneration method of hybrid resin |
| CN109289941A (en) * | 2018-10-29 | 2019-02-01 | 北方华锦化学工业股份有限公司 | Condensate liquid treater method of reproduction |
| CN109876871B (en) * | 2019-03-28 | 2021-12-17 | 江苏核电有限公司 | Efficient resin unloading method for high-pressure ion exchange purification system |
| CN110790343A (en) * | 2019-11-15 | 2020-02-14 | 师宗煤焦化工有限公司 | Mixed bed regeneration method for water conservation and emission reduction |
| CN110860517B (en) * | 2019-12-03 | 2023-09-15 | 浙江华康药业股份有限公司 | Ion exchange resin cleaning system and cleaning method |
| CN111333149A (en) * | 2020-03-18 | 2020-06-26 | 西安热工研究院有限公司 | System for sharing and regenerating acid and alkali for condensate polishing and boiler feed water treatment |
| CN112007700A (en) * | 2020-07-28 | 2020-12-01 | 浙江芯美生物科技有限公司 | Ion exchange system for collagen peptide production |
| CN112403533B (en) * | 2020-11-06 | 2023-07-21 | 安徽皖东树脂科技有限公司 | Purification process and purification equipment for anion exchange resin |
| CN112295611B (en) * | 2020-11-06 | 2022-12-16 | 兖矿鲁南化工有限公司 | Mixed bed regeneration improvement process, system and application |
| CN112916054A (en) * | 2021-01-15 | 2021-06-08 | 清华大学 | Method and device for regenerating ion exchange resin by gas-liquid mixing |
| CN113044919B (en) * | 2021-04-28 | 2023-12-22 | 武汉恩孚水务有限公司 | Power plant condensate fine treatment process and device |
| CN114604936A (en) * | 2022-02-14 | 2022-06-10 | 重庆松藻电力有限公司 | Water production process based on high-speed mixed bed and condensate fine treatment system |
| CN115624989A (en) * | 2022-11-14 | 2023-01-20 | 厦门钨业股份有限公司 | Method for resolving ion exchange resin |
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