CN113264605A - Desulfurization wastewater anti-scaling pretreatment method and system - Google Patents
Desulfurization wastewater anti-scaling pretreatment method and system Download PDFInfo
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Abstract
The invention provides a desulfurization wastewater anti-scaling pretreatment method and a system. The invention discloses an anti-scaling pretreatment method for desulfurization wastewater, which comprises the following steps: A) conveying the effluent of the triple box to a primary reaction tank, adding calcium salt into the primary reaction tank, and stirring; B) the effluent of the first-stage reaction tank enters a second-stage reaction tank, and barium salt is added into the second-stage reaction tank and stirred; C) the effluent of the secondary reaction tank enters a clarification tank, and a flocculating agent is added into the clarification tank for reaction; D) conveying effluent of the clarification tank to a filtering device for filtering; E) and (4) conveying the effluent of the filtering device to a reverse osmosis device for reverse osmosis, and refluxing at least part of reverse osmosis concentrated water to the primary reaction tank. The method and the system can avoid scaling of the desulfurization wastewater in the subsequent concentration process, greatly reduce the operation cost of pretreatment, improve the concentration multiple of the desulfurization wastewater, reduce the volume of the wastewater subjected to subsequent crystallization treatment, and further reduce the treatment cost of a wastewater zero-discharge system.
Description
Technical Field
The invention relates to the technical field of desulfurization wastewater, in particular to a desulfurization wastewater anti-scaling pretreatment method and a system.
Background
The limestone-gypsum wet desulphurization process has the advantages of high desulphurization efficiency, high operation reliability, wide applicable coal range, high utilization rate of the absorbent, high equipment operation rate, low price and easy obtainment of the absorbent and the like, and is a sulfur dioxide removal technology which is widely applied and has mature technology in the world at present.
To prevent the slurry from being too concentrated in soluble chloride ions and fine dust particles, a certain amount of wastewater needs to be discharged from the system to maintain the balance of the materials in the desulfurization unit. The impurities contained in the desulfurization wastewater mainly comprise solid suspended matters, supersaturated sulfite, sulfate, chloride and trace heavy metals. The traditional treatment method of the desulfurization wastewater is mainly a chemical precipitation method, which is commonly called a 'triple box' method. Although the 'triple-box' method can achieve the standard, the effluent still contains a large amount of dissolved salts, the direct discharge can seriously affect the quality of soil and water, and even if the effluent is discharged into a municipal sewage plant, microorganisms in a biochemical pool can be killed, so that the quality of the effluent is deteriorated.
In addition, the technical regulation for wastewater treatment design of a thermal power plant issued in 2006 definitely proposes: the desulfurization wastewater treatment facility of the thermal power plant needs to be independently arranged, treatment and recycling are preferentially considered, no discharge port is arranged, and zero discharge of wastewater must be realized. The technical policy for pollution control of the thermal power plant encourages the thermal power plant to realize the recycling of the wastewater without discharging, and the desulfurization wastewater encourages the adoption of processes such as evaporation drying or evaporation crystallization to realize the non-discharging; a technical route for zero discharge of desulfurization wastewater is also provided in the best feasible technical guideline for pollution control of thermal power plants (HJ 2301-2017).
At present, the desulfurization wastewater zero-discharge technology mainly comprises a flue evaporation method and an evaporative crystallization method. The evaporative crystallization method has the advantages of water resource recovery, industrial salt recovery and the like, and has more prospect. The desulfurization wastewater treated by the triple box has high content of hardness ions, and can cause serious pollution and blockage to subsequent concentration, evaporation and crystallization equipment and pipelines if not treated, and the prior art mainly adopts two technical routes of lime, soda and flocculant and sodium hydroxide and soda to soften the desulfurization wastewater; however, both routes consume large amounts of chemicals and produce large amounts of sludge, increasing wastewater zero discharge and sludge treatment costs.
In view of this, the invention is particularly proposed.
Disclosure of Invention
The invention aims to provide an anti-scaling pretreatment method and system for desulfurization wastewater, which can avoid scaling of the desulfurization wastewater in the subsequent concentration process, greatly reduce the operation cost of pretreatment, improve the concentration multiple of the desulfurization wastewater, reduce the volume of the wastewater subjected to subsequent crystallization treatment, and further reduce the treatment cost of a wastewater zero-discharge system.
The invention provides a desulfurization wastewater anti-scaling pretreatment method, which comprises the following steps:
A) conveying the effluent of the triple box to a primary reaction tank, adding calcium salt into the primary reaction tank, and stirring;
B) the effluent of the first-stage reaction tank enters a second-stage reaction tank, and barium salt is added into the second-stage reaction tank and stirred;
C) the effluent of the secondary reaction tank enters a clarification tank, and a flocculating agent is added into the clarification tank for reaction;
D) conveying effluent of the clarification tank to a filtering device for filtering;
E) and (4) conveying the effluent of the filtering device to a reverse osmosis device for reverse osmosis, and refluxing at least part of reverse osmosis concentrated water to the primary reaction tank.
The inventor finds out through research that: mg (magnesium)2+Can be controlled by pH adjustment and the formation of Mg (OH)2The scale is easy to clean; ca2+CaSO formed4If CaSO can be prevented, the scale is difficult to clean and can cause serious pollution to heat exchange and membrane components4And scale formation can play a role in protecting the membrane module. Desulfurization waste water does not pass through softening treatment, and gets rid of the medicament through selecting suitable sulfate radical, only gets rid of the sulfate radical, can avoid forming calcium sulfate scale deposit material in the follow-up concentration process to reduce the running cost of preliminary treatment by a wide margin, improve the concentration multiple of waste water, reduce the waste water volume of follow-up crystallization treatment, and then reduce waste water zero discharge system's treatment cost.
Meanwhile, if only the barium salt is added to selectively remove sulfate radicals, although the sulfate radicals can be effectively removed to prevent scale formation of subsequent treatment equipment and pipelines, the barium salt has a high price, and especially when the concentration of sulfate ions in the wastewater is too high, a large amount of barium salt needs to be consumed, so that the effect of reducing the treatment cost cannot be well achieved; in addition, the effluent also contains a part of unreacted barium ions, which causes the waste of the medicament and is not beneficial to reducing the treatment cost of the wastewater zero-discharge system.
Therefore, the desulfurization wastewater anti-scaling pretreatment method firstly adds calcium salt into the effluent of the triple box, the calcium salt can further react with sulfate ions in the wastewater to generate calcium sulfate precipitate, and the calcium sulfate precipitate can be discharged through the bottom sludge discharge pipe, so that the concentration of the sulfate ions is reduced, the subsequent dosage of barium salt is reduced, the treatment cost is greatly reduced, and the economy of the whole process is improved.
In the step A), the adding concentration of the calcium salt can be 1-20%, preferably 5-15%; if not specifically stated, the adding concentration of the invention is mass concentration. The calcium salt used in the present invention is not particularly limited, and for example, a sulfate-removing agent such as calcium chloride; meanwhile, the hydraulic retention time of the first-stage reaction tank is not less than 5min, so that the concentration of sulfate radical in the effluent of the first-stage reaction tank is controlled to be lower than 500 ppm.
In the step B), the adding concentration of the barium salt can be 1-20%, preferably 5-15%; the barium salt is not particularly limited, and for example, at least one of barium chloride and barium hydroxide; meanwhile, the hydraulic retention time of the secondary reaction tank is not less than 5min, so that the concentration of sulfate radical in the effluent of the secondary reaction tank is controlled to be less than 10 ppm. The barium salt can further react with sulfate ions in the wastewater to generate barium sulfate precipitate, and the barium sulfate precipitate can be discharged through a bottom sludge discharge pipe.
In step C) of the present invention, the flocculant may be selected from at least one of polyacrylamide and iron salt; the adding concentration of the flocculating agent can be 0.1-0.3%; the hydraulic retention time of the clarifier may be 0.5-1 h. The flocculating agent can improve the settleability of particles, shorten the precipitation time and further reduce the SS content in the desulfurization wastewater.
In step D) of the present invention, the filtration device may employ a conventional filtration device in the art, such as a sand filtration device, a microfiltration device, an ultrafiltration device, etc.; when the head loss of the filtering device exceeds the allowable value, a backwashing pump can be started, backwashing is carried out by utilizing backwashing water, the filtering capacity of the filtering device is recovered, and the backwashing water can adopt water discharged from the filtering device and the like. After the filtration treatment, the SDI value of the effluent of the filtration device can be controlled to be less than 5, and the turbidity is controlled to be less than 1 NTU.
In the step E), the reverse osmosis membrane adopts a roll-type membrane module, a tubular membrane module or a plate-and-frame membrane module; the pressure resistance of the reverse osmosis membrane is 1-75 bar. The reverse osmosis concentrated water generated by the reverse osmosis treatment is rich in calcium ions, and part or all of the calcium ions flow back to the first-stage reaction tank, so that the concentration of the calcium ions in the first-stage reaction tank is further improved, the using amount of calcium salts and barium salts is reduced, the waste of medicaments is avoided, the economy of the whole process flow is improved, and the treatment amount of the reverse osmosis concentrated water is reduced.
The reflux ratio of the reverse osmosis concentrated water is not strictly limited, and the reflux ratio can be 0-95% for example; meanwhile, the other part of reverse osmosis concentrated water can be evaporated and crystallized, so that high-quality industrial salt is generated, and the utilization value of a byproduct of zero discharge of desulfurization wastewater is further expanded; in addition, reverse osmosis effluent can be recycled as industrial water, so that zero emission of desulfurization wastewater is realized.
The invention also provides a desulfurization wastewater anti-scaling pretreatment system which comprises a primary reaction tank, a secondary reaction tank, a clarification tank, a filtering device and a reverse osmosis device which are sequentially arranged and connected, wherein stirrers are arranged in the primary reaction tank and the secondary reaction tank, sludge discharge pipes are arranged at the bottoms of the primary reaction tank, the secondary reaction tank and the clarification tank, and a reverse osmosis concentrated water outlet of the reverse osmosis device is communicated with the primary reaction tank through a return pipeline.
Furthermore, the desulfurization wastewater anti-scale pretreatment system can also comprise an evaporative crystallization device, and a reverse osmosis concentrated water outlet of the reverse osmosis device is also communicated with the evaporative crystallization device through a water outlet pipeline.
In addition, the outlet end of the filter device is provided with a water outlet pipeline and a back flush pipeline, the water outlet pipeline is communicated with the reverse osmosis device, the back flush pipeline is communicated with the filter device, and the water outlet pipeline and the back flush pipeline are respectively provided with a high-pressure pump and a back flush pump.
The implementation of the invention has at least the following advantages:
1. the invention adopts the idea of removing sulfate radicals in the desulfurization wastewater to prevent the subsequent equipment structure, and the calcium salt is added to remove the sulfate radicals before the barium salt is added to remove sulfate radical ions, thereby saving the subsequent use amount of the barium salt and reducing the cost of the whole process.
2. The invention partially or completely reflows the concentrated water generated by reverse osmosis, further improves the concentration of calcium ions in the first-stage reaction tank, reduces the dosage of calcium chloride and barium chloride, avoids the waste of medicaments, improves the economy of the whole process flow and reduces the treatment capacity of the reverse osmosis concentrated water.
3. The method can effectively and economically remove sulfate radicals in the effluent of the triple box, can avoid scaling of subsequent evaporative crystallization treatment facilities, can generate high-quality industrial salt, and expands the utilization value of by-products of zero discharge of desulfurization wastewater.
4. The method and the system can avoid scaling of the desulfurization wastewater in the subsequent concentration process, greatly reduce the operation cost of pretreatment, improve the concentration multiple of the desulfurization wastewater, reduce the volume of the wastewater subjected to subsequent crystallization treatment, and greatly reduce the treatment cost of a wastewater zero-discharge system.
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, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a process flow chart of the desulfurization wastewater scale prevention pretreatment method of example 1 of the present invention.
Description of reference numerals:
1: a first-stage reaction tank; 2: a secondary reaction tank; 3: a clarification tank; 4: a filtration device; 5: a high pressure pump; 6: a reverse osmosis unit; 7: reverse osmosis concentrated water; 8: reverse osmosis yielding water; 9: a sludge discharge pipe; 10: a stirrer; 11: backwashing the water.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms also include the plural forms unless the context clearly dictates otherwise, and further, it is understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, devices, components, and/or combinations thereof.
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. 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.
Example 1
As shown in FIG. 1, the method for the scale prevention pretreatment of desulfurized wastewater of this example comprises the following steps:
conveying the desulfurization wastewater treated by a three-header of a certain power plant into a primary reaction tank 1, wherein the flow of the wastewater is 5 t/h; adding a medicament A, namely a calcium chloride solution, into the primary reaction tank 1, controlling the adding concentration of the calcium chloride solution to be 10%, mixing the calcium chloride solution with reverse osmosis concentrated water 7 flowing back from a reverse osmosis device 6, starting a stirrer 10, fully and uniformly stirring, and ensuring that the actual hydraulic retention time in the primary reaction tank 1 is not less than 5 min. The sulfate radical concentration of the effluent of the first-stage reaction tank 1 is controlled to be lower than 500ppm, and the sludge at the bottom is discharged through a sludge discharge pipe 9.
And the effluent of the first-stage reaction tank 1 enters a second-stage reaction tank 2, a medicament B, namely a barium chloride solution, is added into the second-stage reaction tank 2, the adding concentration of the barium chloride solution is controlled to be 10%, a stirrer 10 is started to stir, and the actual hydraulic retention time in the second-stage reaction tank 2 is not less than 5 min. The concentration of sulfate radical in the water discharged from the secondary reaction tank 2 is controlled to be lower than 10ppm, and the sludge at the bottom is discharged through a sludge discharge pipe 9.
And the effluent of the secondary reaction tank 2 enters a clarification tank 3, a medicament C, namely polyacrylamide serving as a flocculating agent, is added into the clarification tank, the adding concentration of the polyacrylamide is controlled to be 0.2%, the actual hydraulic retention time of the clarification tank 3 is controlled to be 30min, and the sludge at the bottom is discharged through a sludge discharge pipe 9.
The effluent of the clarification tank 3 enters a filter device 4 for filtration treatment, the filter device 4 adopts sand filtration, the SDI value of the effluent of the filter device 4 is 5, and the turbidity is less than 0.8 NTU. When the head loss of the filter device 4 exceeds the allowable value, the backwash pump is started to perform backwash by the backwash water 11, thereby recovering the filtering capacity of the filter device 4.
The effluent of the filtering device 4 enters a reverse osmosis device 6 through a high-pressure pump 5 for reverse osmosis treatment, a reverse osmosis membrane of the reverse osmosis device 6 adopts a roll-type membrane component, and the withstand pressure of the reverse osmosis membrane is 20 bar. The reverse osmosis concentrated water 7 intercepted by the reverse osmosis membrane is rich in calcium ions, and the reverse osmosis concentrated water 7 is refluxed into the first-stage reaction tank 1 according to the reflux proportion of 90 percent, so that the calcium ion concentration in the first-stage reaction tank 1 is improved, and the sulfate radical concentration is further reduced; meanwhile, the other 10 percent of reverse osmosis concentrated water 7 is sent to a flue for evaporation and crystallization, and high-quality industrial salt is produced. And the reverse osmosis effluent 8 formed by the reverse osmosis treatment is reused as industrial water according to the water quality requirement.
According to the desulfurization wastewater anti-scaling pretreatment method, before barium salt is added to remove sulfate ions, calcium salt is added to remove sulfate ions, so that the subsequent use amount of barium salt is saved, and the cost of the whole process is reduced; meanwhile, the concentrated water generated by reverse osmosis is partially or completely refluxed, so that the concentration of calcium ions in the first-stage reaction tank 1 is further improved, the using amounts of calcium chloride and barium chloride are reduced, the waste of medicaments is avoided, the economy of the whole process flow is improved, and the treatment amount of the reverse osmosis concentrated water is reduced; in addition, the pretreatment method of the embodiment can generate high-quality industrial salt while avoiding scaling of evaporative crystallization treatment facilities, and further expands the utilization value of the by-product of zero emission of the desulfurization wastewater.
Example 2
Referring to fig. 1, desulfurization waste water scale control pretreatment systems of this embodiment is including the one-level reaction tank 1, second grade reaction tank 2, clarification tank 3, filter equipment 4 and the reverse osmosis unit 6 that set gradually and connect, be equipped with agitator 10 in one-level reaction tank 1 and second grade reaction tank 2, be equipped with sludge discharge pipe 9 in the bottom of one-level reaction tank 1, second grade reaction tank 2 and clarification tank 3, reverse osmosis unit 6's the dense water export of reverse osmosis is through backflow pipeline and one-level reaction tank 1 intercommunication.
The first-stage reaction tank 1 is mainly used for reacting effluent of a triple box with calcium salt to generate calcium sulfate precipitation; firstly adding a medicament A (such as a calcium chloride solution) into the primary reaction tank 1, and simultaneously starting the stirrer 10 for stirring, wherein the adding concentration of the calcium chloride solution can be 1-20%. In the first-order reaction tank 1, along with the increase of calcium ion concentration, according to the solubility product rule, it can further react with the sulfate ion in the waste water, because calcium sulfate is slightly soluble to produce calcium sulfate and deposit, calcium sulfate deposits and discharges through bottom mud pipe 9, and then has reduced the concentration of sulfate ion.
The secondary reaction tank 2 is mainly used for reacting the wastewater with barium salt to generate barium sulfate precipitate. Adding a medicament B (such as barium chloride or barium hydroxide or a combination of the barium chloride and the barium hydroxide) into the secondary reaction tank 2, wherein the adding concentration of the medicament B can be 1-20%; after the barium salt is added, the sulfate ions in the wastewater can be reduced to be lower than 10ppm, and the generated barium sulfate precipitate is discharged through a bottom sludge discharge pipe 9.
The clarification tank 3 is mainly used for flocculating and precipitating impurities in the wastewater; after the effluent of the secondary reaction tank 2 enters the clarification tank 3, adding a medicament C (namely a flocculating agent, such as polyacrylamide or ferric salt or a combination of the polyacrylamide and the ferric salt) into the clarification tank 3, wherein the adding concentration of the medicament C can be 0.1-0.3%, and the hydraulic retention time of the clarification tank 3 can be controlled to be 0.5-1 h. The flocculating agent can improve the settleability of particles, shorten the precipitation time and further reduce the SS content in the desulfurization wastewater.
The filtering device 4 is mainly used for filtering the wastewater; the filtering device 4 can be a sand filtering device, a micro-filtering device or an ultra-filtering device, etc., an outlet pipe and a back-flushing pipe are arranged at the outlet end of the filtering device 4, the outlet pipe is communicated with the reverse osmosis device 6, the back-flushing pipe is communicated with the filtering device 4, and a high-pressure pump 5 and a back-flushing pump (not shown) are respectively arranged on the outlet pipe and the back-flushing pipe. When the head loss of the filter device 4 exceeds the allowable value, the backwash pump is started to perform backwash by the backwash water 11, thereby recovering the filtering capacity of the filter device 4. The effluent of the filter device ensures that the SDI value is less than 5 and the turbidity is less than 1 NTU.
The reverse osmosis device 6 is mainly used for performing reverse osmosis treatment on the wastewater; the effluent of the filtering device 4 enters a reverse osmosis device 6 through a high-pressure pump 5, the reverse osmosis membrane in the reverse osmosis device 6 can adopt a roll-type membrane module, a tubular membrane module or a plate-frame type membrane module, and the withstand pressure of the reverse osmosis membrane in the reverse osmosis device 6 is controlled to be 1-75 bar. The reverse osmosis concentrated water 7 intercepted by the reverse osmosis membrane is rich in calcium ions, part of the reverse osmosis concentrated water 7 flows back to the first-stage reaction tank 1, the calcium ion concentration in the first-stage reaction tank 1 is improved, the sulfate radical concentration is further reduced, reverse osmosis effluent 8 formed by reverse osmosis treatment can be further recycled as industrial water, and therefore zero discharge of wastewater is achieved.
In addition, the desulfurization wastewater anti-scaling pretreatment system of the embodiment may further include an evaporation crystallization device (not shown), the reverse osmosis concentrated water outlet of the reverse osmosis device 6 may be further communicated with the evaporation crystallization device through a water outlet pipeline, and the other part of reverse osmosis concentrated water 7 may be sent to the evaporation crystallization device for evaporation crystallization, so as to generate high-quality industrial salt and further expand the utilization value of the by-product of desulfurization wastewater zero discharge.
The system of the embodiment is provided with the first-stage reaction tank 1, so that calcium salt is added to remove sulfate radicals before barium salt is added to remove sulfate ions, the subsequent use amount of barium salt is saved, and the cost of the whole process is reduced; meanwhile, the reverse osmosis concentrated water outlet of the reverse osmosis device 6 is communicated with the first-stage reaction tank 1, so that reverse osmosis concentrated water 7 generated by reverse osmosis is recycled, the calcium ion concentration in the first-stage reaction tank 1 is improved, the use amount of calcium chloride and barium chloride is reduced, the waste of medicaments is avoided, the economy of the whole process flow is improved, and the treatment amount of the reverse osmosis concentrated water is reduced; furthermore, the reverse osmosis concentrated water 7 is subjected to evaporative crystallization by arranging the evaporative crystallization device, so that high-quality industrial salt can be generated, and the utilization value of a byproduct of zero emission of desulfurization wastewater is expanded. The desulfurization wastewater anti-scaling pretreatment system of the embodiment can avoid scaling of desulfurization wastewater in the subsequent concentration process, greatly reduces the operation cost of pretreatment, improves the concentration multiple of the desulfurization wastewater, reduces the volume of the wastewater subjected to subsequent crystallization treatment, and greatly reduces the treatment cost of a wastewater zero-discharge system.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The desulfurization wastewater anti-scaling pretreatment method is characterized by comprising the following steps of:
A) conveying the effluent of the triple box to a primary reaction tank, adding calcium salt into the primary reaction tank, and stirring;
B) the effluent of the first-stage reaction tank enters a second-stage reaction tank, and barium salt is added into the second-stage reaction tank and stirred;
C) the effluent of the secondary reaction tank enters a clarification tank, and a flocculating agent is added into the clarification tank for reaction;
D) conveying effluent of the clarification tank to a filtering device for filtering;
E) and (4) conveying the effluent of the filtering device to a reverse osmosis device for reverse osmosis, and refluxing at least part of reverse osmosis concentrated water to the primary reaction tank.
2. The desulfurization wastewater scale prevention pretreatment method according to claim 1, characterized in that in step A), the adding concentration of calcium salt is 1-20%, preferably 5-15%;
preferably, the calcium salt is calcium chloride;
preferably, the hydraulic retention time of the primary reaction tank is not less than 5 min;
preferably, the concentration of sulfate radical in the effluent of the primary reaction tank is controlled to be lower than 500 ppm.
3. The desulfurization wastewater scale prevention pretreatment method according to claim 1, wherein in the step B), the adding concentration of barium salt is 1-20%, preferably 5-15%;
preferably, the barium salt is selected from at least one of barium chloride and barium hydroxide;
preferably, the hydraulic retention time of the secondary reaction tank is not less than 5 min;
preferably, the concentration of sulfate radical in the effluent of the secondary reaction tank is controlled to be lower than 10 ppm.
4. The desulfurization wastewater anti-scaling pretreatment method according to claim 1, wherein in step C), the flocculant is at least one selected from polyacrylamide and iron salt;
preferably, the adding concentration of the flocculating agent is 0.1-0.3%;
preferably, the hydraulic retention time of the clarifier is 0.5-1 h.
5. The desulfurization wastewater scale prevention pretreatment method according to claim 1, wherein in step D), the filtration device is a sand filtration device, a microfiltration device or an ultrafiltration device;
preferably, the water outlet of the filtering device is adopted for backwashing the filtering device;
preferably, the SDI value of the effluent of the filtering device is controlled to be less than 5, and the turbidity is controlled to be less than 1 NTU.
6. The desulfurization wastewater anti-scaling pretreatment method according to claim 1, characterized in that in step E), the reverse osmosis membrane adopts a roll-type membrane module, a tubular membrane module or a plate-and-frame membrane module;
preferably, the reverse osmosis membrane has a pressure resistance of 1 to 75 bar.
7. The desulfurization wastewater scale prevention pretreatment method according to claim 1, wherein in the step E), the reflux ratio of reverse osmosis concentrated water is 0-95%;
preferably, evaporating and crystallizing the other part of the reverse osmosis concentrated water;
preferably, the reverse osmosis effluent is recycled as industrial water.
8. The utility model provides a desulfurization waste water scale control pretreatment systems, its characterized in that, is equipped with the agitator including the one-level reaction tank, second grade reaction tank, clarification tank, filter equipment and the reverse osmosis unit that set gradually and connect in one-level reaction tank and second grade reaction tank, is equipped with the mud pipe in the bottom of one-level reaction tank, second grade reaction tank and clarification tank, and reverse osmosis unit's dense water of reverse osmosis export is through backflow pipeline and one-level reaction tank intercommunication.
9. The desulfurization wastewater anti-scaling pretreatment system of claim 8, further comprising an evaporative crystallization device, wherein the reverse osmosis concentrated water outlet of the reverse osmosis device is further communicated with the evaporative crystallization device through a water outlet pipeline.
10. The desulfurization wastewater anti-scaling pretreatment system of claim 8, wherein an outlet pipe and a back-washing pipe are arranged at the outlet end of the filtration device, the outlet pipe is communicated with the reverse osmosis device, the back-washing pipe is communicated with the filtration device, and the outlet pipe and the back-washing pipe are respectively provided with a high-pressure pump and a back-washing pump.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115231743A (en) * | 2022-09-23 | 2022-10-25 | 大唐环境产业集团股份有限公司 | Low-cost desulfurization wastewater treatment method and system |
| CN115304204A (en) * | 2022-09-15 | 2022-11-08 | 中国科学院青海盐湖研究所 | Method for deeply removing impurity ions in raw material brine for producing metal magnesium by electrolysis |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003008336A2 (en) * | 2001-07-20 | 2003-01-30 | Microbar, Inc. | Reverse osmosis pretreatment using low pressure filtration |
| CN101407356A (en) * | 2008-10-31 | 2009-04-15 | 中南大学 | Method for removing sulfate radical in waste water |
| CN103025403A (en) * | 2010-06-23 | 2013-04-03 | 维利亚水务解决方案及技术支持公司 | A process for reducing the sulfate concentration in a wastewater stream |
| CN105948367A (en) * | 2016-07-20 | 2016-09-21 | 盛发环保科技（厦门）有限公司 | Novel desulfurization waste water zero discharging process and system |
| US20170334752A1 (en) * | 2016-05-19 | 2017-11-23 | AECOM Technical Services, Inc. | Sulfate reduction in flue gas desulfurization system by barium precipitation |
-
2021
- 2021-04-29 CN CN202110473780.1A patent/CN113264605A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003008336A2 (en) * | 2001-07-20 | 2003-01-30 | Microbar, Inc. | Reverse osmosis pretreatment using low pressure filtration |
| CN101407356A (en) * | 2008-10-31 | 2009-04-15 | 中南大学 | Method for removing sulfate radical in waste water |
| CN103025403A (en) * | 2010-06-23 | 2013-04-03 | 维利亚水务解决方案及技术支持公司 | A process for reducing the sulfate concentration in a wastewater stream |
| US20170334752A1 (en) * | 2016-05-19 | 2017-11-23 | AECOM Technical Services, Inc. | Sulfate reduction in flue gas desulfurization system by barium precipitation |
| CN105948367A (en) * | 2016-07-20 | 2016-09-21 | 盛发环保科技（厦门）有限公司 | Novel desulfurization waste water zero discharging process and system |
Non-Patent Citations (1)
| Title |
|---|
| 化学工业部科学技术情报研究所: "《赴美水处理技术及管理考察报告》", 31 January 1982 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115304204A (en) * | 2022-09-15 | 2022-11-08 | 中国科学院青海盐湖研究所 | Method for deeply removing impurity ions in raw material brine for producing metal magnesium by electrolysis |
| CN115231743A (en) * | 2022-09-23 | 2022-10-25 | 大唐环境产业集团股份有限公司 | Low-cost desulfurization wastewater treatment method and system |
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