CN110156209A - A kind of processing system and processing method of wet desulphurization waste water - Google Patents

A kind of processing system and processing method of wet desulphurization waste water Download PDF

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Publication number
CN110156209A
CN110156209A CN201910430684.1A CN201910430684A CN110156209A CN 110156209 A CN110156209 A CN 110156209A CN 201910430684 A CN201910430684 A CN 201910430684A CN 110156209 A CN110156209 A CN 110156209A
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processing system
waste water
sedimentation
softening
filter
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孙虎良
王思珏
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Shanghai Sijiu Science And Technology Development Co Ltd
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Shanghai Sijiu Science And Technology Development Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
    • B01D53/502—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific solution or suspension
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/96—Regeneration, reactivation or recycling of reactants
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/30—Alkali metal compounds
    • B01D2251/304—Alkali metal compounds of sodium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/60—Inorganic bases or salts
    • B01D2251/604—Hydroxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • 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
    • C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
    • 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
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/18—Nature of the water, waste water, sewage or sludge to be treated from the purification of gaseous effluents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/02—Softening water by precipitation of the hardness
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F7/00—Aeration of stretches of water

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
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Abstract

The present invention provides the processing system and processing method of a kind of wet desulphurization waste water, the processing system includes sequentially connected reaction unit, sedimentation device, softening plant and filter device；The processing system further includes the waste residue dehydration device connecting with the sedimentation device outlet at bottom.The processing method includes: that wet desulphurization waste water and lye react to obtain reaction solution in reaction unit, reaction solution is passed through sedimentation device sedimentation separation and obtains clear liquid and sediment, sediment is carried out dehydrating in waste residue dehydration device, clear liquid reacts to obtain bating liquor and precipitating with softening agent in softening plant, and bating liquor passes through the isolated dope of filter device and permeate.The present invention realizes the regeneration of NaOH absorbent, and not calcium ions and calcic solids in regeneration lye by the synergistic effect of softening plant and filter device, solves the problems, such as that absorbent internal cause calcic leads to absorption tower fouling.

Description

A kind of processing system and processing method of wet desulphurization waste water
Technical field
The invention belongs to field of waste water treatment, are related to the processing system and processing method of a kind of wet desulphurization waste water, especially It is related to the processing system and processing method of a kind of catalytic cracking flue gas desulfurization device efflux wastewater.
Background technique
The sulfur method of most domestic catalytic cracking unit regenerated flue gas uses NaOH as desulfurizing agent, is washed using wet process Technique is washed to SO contained in flue gas2It is washed, to reach SO in removing flue gas2Purpose.
In catalytic cracking unit regenerated flue gas wet desulfuration tower, wash tower bottoms are contained into Na2SO3、NaHSO3With Na2SO4Slurries squeezed at the top of absorption tower by circulating pump, sprayed from the atomizer at the top of absorption tower, slurries drop from top to down It falls.Regenerated flue gas is passed through scrubbing tower from the middle and lower part on absorption tower, flows from below to up in absorption tower.In scrubbing tower, slurries It is contacted with flue gas adverse current, washing absorption is carried out to flue gas.The SO during counter current contacting of slurries and flue gas, in flue gas2Quilt Na in slurries2SO3Reaction generates NaHSO3, to achieve the purpose that purifying and catalyzing regenerated flue gas.Catalytic regeneration flue gas SO2's Removal efficiency is 95% or more.
Absorption tower is continuously discharged as desulfurization wastewater in the slurries of absorb the bottom of the tower, a part.It is discharged in the waste water on absorption tower, Main component is Na2SO3、NaHSO3And Na2SO4Deng.Due to containing SO3 2-And HSO3 -Equal substances, COD higher need further Oxidation, to reduce the COD value of efflux wastewater.Oxidation process is carried out in a manner of being passed through air in oxidation tank, by waste water In Na2SO3And NaHSO3It is oxidized to Na2SO4, in order to keep oxidation process pH value to maintain neutrality, need in oxidation process NaOH is added to adjust the pH value of waste water.
After pH value of waste water and COD after oxidation reach discharge standard, discharge is concentrated, Entry Firm sewerage or city are dirty Water system.Its salt content of the catalytic cracking and desulfurizing waste water of outlet is about 5-8%, easily causes to rush to the microorganism of sewage disposal system It hits.The wastewater flow rate of outlet, depending on the SO in catalytic regeneration flue gas2Content, SO2Content is high, need the wastewater flow rate of outlet then compared with Greatly.To the regenerated flue gas that a set of 2,000,000 tons/year of catalytic cracking units generate, if total flue gas flow is 360000Nm3/ h, SO2 Total amount is 620kg/h, the SO after desulfurization process2Content is 21kg/h, SO2Removing amount be 599kg/h.Using NaOH as de- When sulphur agent, the desulfurization wastewater amount containing solute about 5.2% that can discharge is about 27 tons/when.
Also there is the SO absorbed in flue gas using Dual alkali in the country2Process route, Dual alkali technique refers to be made using NaOH PH for absorbent, absorption tower is controlled 6.5 or so, uses Na2SO3With the SO in flue gas2Reaction generates NaHSO3.In absorption tower Slurries in reaction tank 1 use Ca (OH)2Reaction generates CaSO3And NaOH.Slurries after reaction enter sedimentation basin, and it is solid to carry out liquid Separation, the height slag containing solid waste for precipitating bottom of pond portion are dehydrated by vacuum belt dewaterer, and the clear liquid of sedimentation basin returns to absorption tower conduct Absorbent.
But in the actual production process, there is following two aspects in Dual alkali technique:
(1) what is be discharged in absorption tower is rich in Na2SO3、NaHSO3Slurries and Ca (OH)2After reaction, the CaSO of formation3Partial size Very small (general 15-30 μm), the catalyst particle size being washed down in flue gas, due to partial size very little, are being used less than 20 μm When vacuum belt dewaterer carries out dehydrating operations, small particle can block filter cloth, cause the water content of dehydration product still higher (water content is 30~50%), and the pH of dehydrate is higher than 8.5-11, has difficulties, needs in transport factory and waste residue utilization Professional landfill disposal.
(2) since Dual alkali is that mixture after reacting is precipitated by sedimentation basin, supernatant liquor is sent directly into absorption tower. In sedimentation basin supernatant liquor, contain Ca (OH)2、CaSO3And CaSO4Equal calcics particulate matter and other Ca2+.These calcic particles Object or ion can generate CaSO after entering absorption tower in absorption tower3·1/2H2O and CaSO4·2H2Crystalline solid, knot is blended in O Crystal is easily attached to spray head in absorption tower, crossbeam, demister, absorption tower serum recycle pump intake etc..CaSO4·2H2O knot Crystal is hard crystal structure, and insoluble in acid, the Dual alkali catalytic cracking flue gas desulfurization devices that cover make more because crystalline solid blocks Desulfurizer is stopped work.Catalytic cracking unit regeneration flue gas desulfurization all devices using Dual alkali technique in the country's are because absorbing at present Calcic class Crystallization Plugging in tower and it is out of service or be changed to the mono- Alkali absorption of NaOH.
The country, as the process units for urging cracking unit desulfurization, stops transporting using Dual alkali technique because of system jams Row, therefore the sewage of petroleum enterprise catalytic cracking flue gas desulfurization outlet at present, are all directly entered sewage treatment system, enterprise substantially Unite or be discharged into urban sewage system.
For catalytic cracking and desulfurizing waste water to the serious impact of sewage disposal system, Ye You enterprise begin one's study crystallisation or Film pre-processes crystallisation.Wet desulphurization waste water is handled using multiple-effect evaporation, desulfurization wastewater is subjected to multiple evaporation and is mentioned It is dense, improve the salt content in waste water.Generally use two kinds of salt crystallization modes:
(1) direct crystallization method: waste water is evaporated with steam, so that the solids such as the salt in waste liquid be made to crystallize；
(2) it crystallisation by cooling method: after the salt in waste water to be evaporated to certain concentration, is cooled down, using salt in low temperature The salt crystallization of waste water is achieved the purpose that remove salinity by the small feature of solubility.
In order to reduce the energy consumption of evaporative crystallization, also has and first pre-process the method for combining crystallization with film, waste water is mentioned in advance with film It is dense, then multiple-effect evaporation is carried out, but the investment of this method is larger, energy consumption is higher.
In general, Dual alkali technique can not be still effectively utilized at present to handle catalytic cracking and desulfurizing waste water, because This needs to improve existing treatment process to cooperate Dual alkali process catalytic cracking and desulfurizing waste water.
Summary of the invention
In view of the deficiencies of the prior art, the present invention intends to provide a kind of processing system of wet desulphurization waste water And processing method, the regeneration of NaOH absorbent is realized by the synergistic effect of softening plant and filter device, and regenerate lye In not calcium ions and calcic solids, solve the problems, such as that absorbent internal cause calcic leads to absorption tower fouling.
To achieve this purpose, the present invention adopts the following technical scheme:
In a first aspect, the present invention provides a kind of processing system of wet desulphurization waste water, the processing system include according to Reaction unit, sedimentation device, softening plant and the filter device of secondary connection.
The processing system further includes the waste residue dehydration device connecting with the sedimentation device outlet at bottom.
The present invention passes through the synergistic effect of softening plant and filter device, uses CO2Or carbonate is soft to reaction clear liquid progress Change processing, reduces the calcium ion content of dissolution；By filter device, the calcic solid suspension to suspend in clarified solution is removed, from And system is avoided to cause absorption system fouling risk because bringing calcium constituent (solid-state or ionic state) into.
As currently preferred technical solution, dreg slurry is provided between the sedimentation device and waste residue dehydration device Pump.
Preferably, filter pump is provided between the softening plant and the filter device.
As currently preferred technical solution, the sedimentation device is a settling tank.
Agitating device is equipped in the settling tank.
The sedimentation bottom of pond portion is exported equipped with sediment.
As currently preferred technical solution, the softening plant includes a softening pond.
Preferably, the softening plant bottom is equipped with aerator.
Preferably, agitating device is equipped in the softening plant.
As currently preferred technical solution, the filter device is ultrafiltration apparatus or nanofiltration device.
Preferably, the filter core of the filter device uses ceramic membrane filter core.The filter core needs that the present invention uses use can It is prepared by the material of acid-fast alkali-proof.
Preferably, filter device includes at least two groups filter core.The purpose that multiple groups filter core is arranged is to realize filter process Continuity, those skilled in the art can also rationally select filter core group number according to the flow and filtration types of bating liquor It selects, and every group of filter core can individually regenerate.
As currently preferred technical solution, the waste residue dehydration device is that spray drying tower or vacuum belt are dehydrated Machine, preferably spray drying tower.Present invention preferably employs spray drying towers as waste residue dehydration device, this is because in settling tank CaSO is rich in isolated bottom slurry3And the catalyst that small part is got off by flue gas washing, and CaSO3And catalyst In the smaller (CaSO of partial size3Partial size generally at 15-30 μm, catalyst particle size is generally less than 20 μm), since partial size is smaller, When using vacuum belt dewaterer dehydration, small particle can block filter cloth, cause the product water content of dehydration higher (aqueous Amount is in 30-50%), and the pH of dehydrate is higher than 11, has difficulties, is needed at professional landfill in transport factory and waste residue utilization Reason.Therefore, in order to solve vacuum belt dewaterer because reaction product partial size it is smaller caused by be dehydrated difficult, preferably reaction is generated CaCO3·1/2H2The sediments such as O are spray-dried.Precipitating bottom of pond portion slurry (concentration is in 10-30%) is passed through into atomization spray Head (centrifugation or double-current spray gun body) is sprayed by the top of spray drying tower, is carried out in the spray drying tower with partially non-desulfurization fume It reacts, NaOH contained in slurry and the SO in flue gas2Reaction generates Na2SO3, Ca (OH) in slurry2With the SO in flue gas2Instead CaSO should be generated3, in spray drying tower, the waste heat that non-desulfurization fume is utilized evaporates the residual moisture in slurry, thus Achieve the purpose that the innoxious zero-emission of slurry.The SO in non-desulfurization fume is utilized in one aspect of the present invention as a result,2Occur with slurry Reaction is filled or is recycled convenient for subsequent centralized recovery；On the other hand, the present invention also uses the heat more than needed in non-desulfurization fume Amount is dried slurry, is not necessarily to additional supplemental heat source, reduces thermal losses, reduce processing cost.It is spraying dry Dry tower can use carbon steel (scale anticorrosion), and project cost is low.
Preferably, atomising device is provided at the top of the spray drying tower.
Preferably, the atomising device is high speed atomisation wheel or double-current spray gun body.
Preferably, the smoke outlet of the spray drying tower is equipped with dust-extraction unit.The solids of discharge is dry by spraying Bag filter is collected after dry tower, and water capacity is low, facilitates comprehensive utilization or landfill.
Preferably, the dust-extraction unit is bag filter.
The specific structure of spray drying tower is not belonging to protection scope of the present invention, as long as the technology of the present invention effect may be implemented Other types spray drying tower be used equally in the application.Illustratively, the present invention provides a kind of tools of spray drying tower Body structure, including top are provided with atomising device, and atomising device is that high speed atomisation wheel or double-current spray gun body, smoke outlet are equipped with Bag filter.It, will be after slurry spraying, with waste heat boiler by high speed atomisation wheel or double-current spray gun body etc. in spray drying tower Partially catalyzed cracking regenerated flue gas be spray-dried.Ca contained in slurries (OH)2And NaOH etc. the and SO in flue gas2Instead It answers, generates CaSO3And Na2SO3Deng.Dust contained in the flue gas of spray drying tower outlet, is recycled in bag filter.Cloth Flue gas after bag dust collector returns to flue and enters wet scrubbing tower after being pressurized by booster fan.Into spray drying The waste residue water content that exhaust gas volumn is handled as needed determines that the present invention is not especially limited this.It is generally held away from and does by spraying The flue-gas temperature of dry tower is at 80-90 DEG C.
Second aspect, the present invention provides a kind of processing method of wet desulphurization waste water, using being described in first aspect System handles desulfurization wastewater, concrete operations are as follows:
Wet desulphurization waste water and lye react to obtain reaction solution in reaction unit, and it is heavy that reaction solution is passed through sedimentation device Isolated clear liquid and sediment drop, sediment is carried out dehydrating in waste residue dehydration device, clear liquid in softening plant with Softening agent reacts to obtain bating liquor and precipitating, and bating liquor passes through the isolated dope of filter device and permeate.
Specifically, the present invention provides a kind of processing steps of wet desulphurization waste water:
(1) it reacts
The waste water of catalytic cracking flue gas desulfurization device absorption tower outlet, the Na mainly containing about 5-8%2SO3、NaHSO3And it is micro- The NaCl and Na of amount2SO4.The waste water of absorption tower outlet is introduced into reaction unit, with the Ca (OH) through nitrifying2Slurries carry out anti- It answers, CaSO is generated in reaction unit4/CaSO3And NaOH.The pH for controlling reaction solution is 8.5-13, it is preferable that pH value control exists 9-11。
(2) precipitating and solid dehydration
Reaction product is from the upper outlet of reaction unit, into carrying out sedimentation separation in the sedimentation device with agitating device Obtain supernatant liquor and bottom sediment.In sedimentation device, CaSO3·1/2H2O、CaSO4·2H2O and unreacted Ca (OH)2It is deposited on the bottom of sedimentation device, is pumped into waste residue dehydration device and is carried out dehydrating by dreg slurry.
(3) soften
Supernatant liquor overflow enters softening plant, and CO is passed through in softening plant2Or sodium carbonate liquor or bicarbonate is added Sodium solution, calcium ion and CO in clear liquid2、CO3 2+Or HCO3 -Reaction generates CaCO3Precipitating.
When being passed through CO in softening plant2Gas, by the way that the aerator of softening plant bottom is arranged in microbubble Mode is passed through CO into softening plant2, calcium ion contained in solution is completely converted into CaCO3Precipitating.
When being passed through sodium carbonate or sodium bicarbonate solution in softening plant, clear liquid exists with sodium carbonate or sodium bicarbonate solution It reacts under conditions of stirring.In the present invention, carbon dioxide and sodium carbonate and/or carbon can also be passed through to softening plant simultaneously Sour hydrogen sodium.
CO is added2Amount or sodium carbonate, sodium bicarbonate amount need guarantee softening clear liquid in Ca2+Reaction generates heavy completely It forms sediment.
(4) it filters
The Ca of free state is substantially not present after sofening treatment in clear liquid2+.It is softened that treated that bating liquor main component is NaOH and micro NaCl and Na2SO4.Meanwhile there is also Ca (OH) in solution2、CaSO4And CaCO3It suspends etc. small scale solid Object, bating liquor are sent into filter device after filter pump boosts and remove above-mentioned small scale solid suspension contained in solution.By The permeate without solid particulate matter has been obtained after filter, is sent into supplement SO of the absorption tower as absorption tower2Absorbent is filled by filtering The dope for setting retention returns in sedimentation device.
As currently preferred technical solution, the wet desulphurization waste water is the suction of catalytic cracking flue gas desulfurization device Receive the efflux wastewater that tower generates.
It preferably, include sodium hydrogensulfite, sodium sulfite, sodium chloride and sodium sulphate and can in the wet desulphurization waste water Other trace metal salts (such as magnesium sulfite, magnesium sulfate) of energy.
Preferably, the lye is calcium hydroxide solution.
Preferably, the additional amount of lye is controlled by the pH value of reaction solution.
Preferably, the pH value of the reaction solution is controlled in 8.5-13, for example, can be 8.5,9,9.5,10,10.5,11, 11.5,12,12.5 or 13, it is further preferred that the pH value of the reaction solution is controlled in 9-11.
As currently preferred technical solution, the softening agent is carbon dioxide and/or carbonate solution.
Preferably, the softening agent is the mixing of one or both of sodium carbonate liquor or sodium bicarbonate solution, into Preferably, the softening agent is sodium carbonate liquor to one step.
Preferably, when the softening agent is carbon dioxide, the mode for being passed through softening agent are as follows: by being set to The aerator for stating softening plant bottom is passed through carbon dioxide.
Preferably, when the softening agent is sodium carbonate liquor, the clear liquid is sent out under agitation with softening agent Raw reaction.
Preferably, described to be precipitated as calcium carbonate.
As currently preferred technical solution, the processing method further include: the dope that bating liquor is obtained by filtration returns Settling tank is returned, the permeate that bating liquor is obtained by filtration is sent into the absorption tower of catalytic cracking flue gas desulfurization device for absorbing cigarette Gas.
Numberical range of the present invention not only includes enumerated point value, further includes the above-mentioned numerical value not included Arbitrary point value between range, as space is limited and for concise consideration, range described in the present invention no longer exclusive list includes Specific point value.
Compared with prior art, the invention has the benefit that
1, the present invention will absorb SO in absorption tower by regenerated mode2Desulfurization wastewater by cheap through nitrifying Ca (OH) afterwards2Slurries regeneration, so that the utilization rate of NaOH absorbent be made to increase considerably, the wastewater flow rate of system outlet is significantly It reduces, the water of system supplement is also greatly lowered.To considerably reduce the operating cost of desulphurization system, operation is reduced Pressure.
2, it is acted synergistically by softening plant and filter device, uses CO2Or carbonate carries out sofening treatment to reaction clear liquid, Reduce the calcium ion content of dissolution.By filter device, remove the calcic solids to suspend in clarified solution, thus avoid system because It brings calcium (solid-state or ionic state) into and causes absorption system fouling risk.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the processing system for the wet desulphurization waste water that the specific embodiment of the invention provides.
Wherein, 1- reaction tank；2- settling tank；3- slurry liquid pump；4- softens pond；5- filter pump；6- filter device；7- waste residue Waste residue dehydration device.
Specific embodiment
To further illustrate the technical scheme of the present invention below with reference to the accompanying drawings and specific embodiments.
In a specific embodiment, the present invention provides a kind of processing system of wet desulphurization waste water, the places Reason system is as shown in Figure 1, include sequentially connected reaction tank 1, settling tank 2, softening pond 4 and filter device 6, the processing system System further includes the waste residue dehydration device waste residue waste residue dehydration device 7 connecting with 2 outlet at bottom of settling tank.
It is provided with slurry liquid pump 3 between the settling tank 2 and waste residue dehydration device waste residue waste residue dehydration device 7, it is described soft Change and is provided with filter pump 5 between pond 4 and filter device 6.
Agitating device is equipped in the settling tank 2, bottom is exported equipped with sediment.
4 bottom of softening pond is equipped with aerator, and inside is additionally provided with agitating device.
The filter device 6 is ultrafiltration apparatus or nanofiltration device, and filter device 6 is used including at least two groups filter core filter core Ceramic membrane filter core.
The waste residue dehydration device waste residue waste residue dehydration device 7 is spray drying tower or vacuum belt dewaterer；Wherein, It is provided with atomising device at the top of spray drying tower, atomising device is high speed atomisation wheel or double-current spray gun body, spray drying tower Smoke outlet is equipped with dust-extraction unit, and dust-extraction unit is bag filter.
Embodiment 1
A kind of processing system of wet desulphurization waste water is present embodiments provided, the processing system uses specific embodiment party The processing system for the wet desulphurization waste water that formula provides, wherein waste residue dehydration device waste residue waste residue dehydration device 7 is spray drying Tower, filter device 6 are nanofiltration device, and filter device 6 includes two groups of filter cores.
The present embodiment is handled wet desulphurization waste water using above-mentioned processing system, and the processing operation specifically includes Following steps:
(1) it reacts
The wet desulphurization waste water of 24682kgt/h is discharged into reaction tank 1,10% Ca (OH) is passed through into reaction tank 12 Slurry flow 2619kg/h；Wet desulphurization waste water and Ca (OH)2It is sufficiently reacted in whipping process, generates CaSO4And NaOH.
(2) it settles
Reaction product is discharged into the sedimentation basin with agitating device from the top of reaction tank 1 and carries out sedimentation separation of solid and liquid, Obtain bottom slurry and supernatant liquor.It wherein, include CaSO in the slurry of bottom3·1/2H2O、CaSO4·2H2O and slightly mistake The Ca (OH) of amount2Micro-soluble material, bottom slurry are sent into spray drying tower by slurry liquid pump 3 and are carried out dehydrating.
(3) it is dehydrated
Bottom slurry is spray-dried with the flow of 25230kg/h with regeneration fume from catalytic cracking, contained in slurries Ca(OH)2And NaOH etc. the and SO in flue gas2Reaction generates CaSO3And Na2SO3Deng；Wherein, the solid content of slurry is about 20%, The regenerated flue gas amount for being passed through spray drying tower is 16000Nm3/ h, the temperature of regenerated flue gas are 90 DEG C.
After spray drying, the temperature of exiting flue gas is down to 90 DEG C, and contained dust is in bag filter in exiting flue gas Middle carry out centralized recovery.
(4) soften
The supernatant liquor that step (2) obtains enters softening pond 4 with the flow overflow of 25230kg/h, in softening pond 4, leads to It crosses aerator and is passed through CO2Gas, the volume flow that CO2 is passed through are 6000L/h (standard state)；Calcium ion and CO in clear liquid2Reaction Generate CaCO3Precipitating.Main component in bating liquor is soluble NaOH, micro NaCl and Na2SO4；And insoluble or slightly soluble Ca (OH)2、CaSO4、CaCO3Deng a small amount of small scale solid suspension.
(5) it filters
Bating liquor is sent into filter device 6 after the boosting of filter pump 5, and it is outstanding to remove a small amount of small scale solid contained in solution Floating object.Permeate is sent into absorption tower as SO2The dope of the supplement of absorbent, retention returns to settling tank 2.
After wet desulphurization wastewater treatment, analysis is sampled to permeate, calculates the Ca in permeate2+Content is 2mg/L or less.
Embodiment 2
Embodiment 2 the difference from embodiment 1 is that, in step (4) softening process, into softening pond 4, to be passed through 10% dense The Na of degree2CO3Solution 30kg/h, under stirring conditions, calcium ion and Na in clear liquid2CO3Reaction generates CaCO3Precipitating.Its His processing step is same as Example 1.
After wet desulphurization wastewater treatment, analysis is sampled to permeate, calculates the Ca in permeate2+Concentration is 2mg/L or less.
Comparative example 1
Comparative example 1 the difference from embodiment 1 is that, save softening pond 4 and ultrafiltration apparatus in the processing system, walked in processing Step (4) softening and step (5) filtering are saved in rapid, and the supernatant that sedimentation obtains is sent directly into and is used to supplement in absorption tower SO2Absorbent, in addition to this, other devices, process route and operating parameter etc. are same as Example 1 in system.
In the long-time use process of absorption tower, stop work in discovery tower because of crystalline solid blocking, this is because, sedimentation obtains Supernatant in contain Ca (OH)2、CaSO4、CaSO3And the Ca of other free states2+, after calcic clear liquid enters absorption tower, inhaling CaSO can be generated by receiving in tower4·2H2The calcics crystalline solid such as O, these calcic crystalline solid be easily attached to beam inside absorption tower, nozzle, At the dead angle of pipeline.Due to the crystalline solid of gypsum be it is very fine and close, the crystalline solid in absorption tower will cause system jams, from And prevent device from long-term operation.
Comparative example 2
Comparative example 2 the difference from embodiment 1 is that, save in the processing system softening pond 4, step is saved in processing step Suddenly (4) soften, and the supernatant that sedimentation obtains is passed directly into ultrafiltration apparatus and is filtered separation, and isolated permeate is logical Enter in absorption tower for supplementing SO2Absorbent, in addition to this, other devices, process route and operating parameter etc. and reality in system It is identical to apply example 1.
It is identical as the result of comparative example 1, in the long-time use process of absorption tower, stop in discovery tower because of crystalline solid blocking Work.This is because still containing Ca (OH) in the clear liquid that sedimentation obtains2、CaSO4、CaSO3And other Ca2+If above-mentioned clear liquid is straight It connects in ultrafiltration apparatus, on the one hand easily filter core is caused to block, the replacement cycle shortens, and filtering cost increases；On the other hand, portion Divide free Ca2+It is difficult to fully erased to enter in permeate through filter core, containing Ca by ultrafiltration apparatus2+Permeate again It is passed through in absorption tower, meeting and SO2It reacts and crystallizes to obtain CaSO4·2H2O crystalline solid equally will cause absorption tower blocking, shorten The cycle of operation of equipment.
Comparative example 3
Comparative example 3 the difference from embodiment 1 is that, save ultrafiltration apparatus in the processing system, saved in processing step Step (5) filtering, the bating liquor obtained after softening is sent directly into and is used to supplement SO in absorption tower2In addition to this absorbent is Other devices, process route and operating parameter etc. are same as Example 1 in system.
It is identical as the result of comparative example 1, in the long-time use process of absorption tower, stop in discovery tower because of crystalline solid blocking Work.Although this is because, converting the calcium ion in supernatant to insoluble CaCO by sofening treatment3Precipitating, eliminate from The calcium of sub- state, but necessarily there is also a small amount of Ca (OH) in bating liquor2、CaSO4Etc. sl. sol. solid suspension, this part Calcic suspended matter enter absorption tower after with SO2It reacts, generates CaSO3, CaSO is generated after oxidation4·2H2O can equally be led Absorption tower blocking is caused, the accidents such as device shut-down are caused.
It can thus be seen that the present invention be by that will soften and filtering combines, softening operation is by soluble Ca2+It is converted into Insoluble CaCO3Precipitating, filter operation retain insoluble and microsolubility calcium salt, and softening and filtering are combined and greatly dropped Free state Ca in low clear liquid2+And insoluble and microsolubility calcium salt content, so as to avoid absorption tower because blocking causes The accidents such as shut-down.
The Applicant declares that the foregoing is merely a specific embodiment of the invention, but protection scope of the present invention not office It is limited to this, it should be clear to those skilled in the art, any to belong to those skilled in the art and take off in the present invention In the technical scope of dew, any changes or substitutions that can be easily thought of, and all of which fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. a kind of processing system of wet desulphurization waste water, which is characterized in that the processing system includes sequentially connected reaction Device, sedimentation device, softening plant and filter device；
The processing system further includes the waste residue dehydration device connecting with the sedimentation device outlet at bottom.
2. processing system according to claim 1, which is characterized in that between the sedimentation device and waste residue dehydration device It is provided with slurry liquid pump；
Preferably, filter pump is provided between the softening plant and the filter device.
3. processing system according to claim 1 or 2, which is characterized in that the sedimentation device is a settling tank；
Agitating device is equipped in the settling tank；
The sedimentation bottom of pond portion is exported equipped with sediment.
4. processing system according to claim 1-3, which is characterized in that the softening plant includes one soft Change pond；
Preferably, the softening plant bottom is equipped with aerator；
Preferably, agitating device is equipped in the softening plant.
5. processing system according to claim 1-4, which is characterized in that the filter device is ultrafiltration apparatus Or nanofiltration device；
Preferably, the filter core of the filter device uses ceramic membrane filter core；
Preferably, filter device includes at least two groups filter core.
6. processing system according to claim 1-5, which is characterized in that the waste residue dehydration device is spraying Drying tower or vacuum belt dewaterer, preferably spray drying tower；
Preferably, atomising device is provided at the top of the spray drying tower；
Preferably, the atomising device is high speed atomisation wheel or double-current spray gun body；
Preferably, the smoke outlet of the spray drying tower is equipped with dust-extraction unit；
Preferably, the dust-extraction unit is bag filter.
7. a kind of processing method of wet desulphurization waste water, which is characterized in that utilize system pair described in any one of claims 1-6 Desulfurization wastewater is handled, concrete operations are as follows:
Wet desulphurization waste water and lye react to obtain reaction solution in reaction unit, and reaction solution is passed through sedimentation device sedimentation point From clear liquid and sediment is obtained, sediment is carried out dehydrating in waste residue dehydration device, clear liquid in softening plant with softening Agent reacts to obtain bating liquor and precipitating, and bating liquor passes through the isolated dope of filter device and permeate.
8. processing method according to claim 7, which is characterized in that the wet desulphurization waste water is catalytic cracking flue gas The efflux wastewater that the absorption tower of desulfurizer generates；
It preferably, include sodium hydrogensulfite, sodium sulfite, sodium chloride and sodium sulphate in the wet desulphurization waste water；
Preferably, the lye is calcium hydroxide solution；
Preferably, the additional amount of lye is controlled by the pH value of reaction solution；
Preferably, the pH value control of the reaction solution is in 8.5-13, it is further preferred that the pH value of the reaction solution is controlled in 9- 11。
9. processing method according to claim 7 or 8, which is characterized in that the softening agent is carbon dioxide and/or carbon Acid salt solution；
Preferably, the softening agent is the mixing of one or both of sodium carbonate liquor or sodium bicarbonate solution, further Preferably, the softening agent is sodium carbonate liquor；
Preferably, when the softening agent is carbon dioxide, the mode for being passed through softening agent are as follows: described by being set to The aerator of softening plant bottom is passed through carbon dioxide；
Preferably, when the softening agent is sodium carbonate liquor, the clear liquid and softening agent occur instead under agitation It answers；
Preferably, described to be precipitated as calcium carbonate.
10. according to the described in any item processing methods of claim 7-9, which is characterized in that the processing method further include: soft Change the dope that liquid is obtained by filtration and return to settling tank, the permeate that bating liquor is obtained by filtration is sent into catalytic cracking flue gas desulfurization device For absorbing flue gas in absorption tower.
CN201910430684.1A 2019-05-22 2019-05-22 A kind of processing system and processing method of wet desulphurization waste water Pending CN110156209A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5702572A (en) * 1995-11-27 1997-12-30 Ebara Corporation Method for treating exhaust gases and foul water
CN1803689A (en) * 2005-12-19 2006-07-19 北京朗新明环保科技有限公司 Dehydration method and apparatus of flue gas desulfurization gypsum slurry
WO2014088826A1 (en) * 2012-12-07 2014-06-12 Aquatech International Corporation Water treatment process
CN105481157A (en) * 2015-12-18 2016-04-13 王辛平 Method for zero emission treatment of desulfurization waste water based on flue gas waste heat evaporation
CN105859006A (en) * 2016-05-23 2016-08-17 海博伦（苏州）环境科技股份有限公司 Desulfurization waste water reuse and zero discharge system and technology
CN109399855A (en) * 2018-12-17 2019-03-01 新疆天富集团有限责任公司 A kind of zero emission treatment of desulfured waste water

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5702572A (en) * 1995-11-27 1997-12-30 Ebara Corporation Method for treating exhaust gases and foul water
CN1803689A (en) * 2005-12-19 2006-07-19 北京朗新明环保科技有限公司 Dehydration method and apparatus of flue gas desulfurization gypsum slurry
WO2014088826A1 (en) * 2012-12-07 2014-06-12 Aquatech International Corporation Water treatment process
CN105481157A (en) * 2015-12-18 2016-04-13 王辛平 Method for zero emission treatment of desulfurization waste water based on flue gas waste heat evaporation
CN105859006A (en) * 2016-05-23 2016-08-17 海博伦（苏州）环境科技股份有限公司 Desulfurization waste water reuse and zero discharge system and technology
CN109399855A (en) * 2018-12-17 2019-03-01 新疆天富集团有限责任公司 A kind of zero emission treatment of desulfured waste water

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