CN111606496A

CN111606496A - Coking wastewater treatment device and method

Info

Publication number: CN111606496A
Application number: CN202010348940.5A
Authority: CN
Inventors: 郝东珍; 刘洪泉; 李瑞斋
Original assignee: Hebei Synergy Water Treatment Technology Co ltd
Current assignee: Hebei Synergy Water Treatment Technology Co ltd
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2020-09-01
Anticipated expiration: 2040-04-28
Also published as: CN111606496B

Abstract

The invention provides a treatment device and a treatment method for coking wastewater, wherein the device comprises: an ammonia evaporation and evaporation unit, a Ca/COAOC/Ca treatment unit, a filtration and adsorption unit, a reverse osmosis and electrodialysis unit and a bipolar membrane electrodialysis unit. According to the coking wastewater treatment device and the treatment method provided by the invention, coking residual ammonia water, coking production circulating cooling sewage, coking plant area biochemical sewage and terrace washing water are comprehensively treated, so that zero discharge of coking wastewater can be realized with low energy consumption and low cost.

Description

Coking wastewater treatment device and method

Technical Field

The invention belongs to the technical field of coking chemical industry, and particularly relates to a coking wastewater treatment device and a coking wastewater treatment method.

Background

With the development of the steel industry, a large amount of coking wastewater is discharged. Wherein, the residual ammonia water accounts for about 25.5 percent, the flushing of the coking plant terrace and the domestic sewage accounts for about 9.6 percent, and the circulating cooling pollution discharge and power sewage discharge water of the coking production accounts for about 64.9 percent; especially residual ammonia water, which contains various pollutants such as ammonia, hydrogen sulfide, hydrogen cyanide, phenol, pyridine, quinoline, indole, naphthalene, biphenyl, anthracene, tar and the like.

Generally, coking residual ammonia water is firstly subjected to ammonia distillation treatment, ammonia distillation wastewater and domestic sewage are subjected to biochemical treatment, biochemical drainage and most of circulating cooling sewage produced by coking, and the circulating cooling sewage is finally used for wet quenching of incandescent coke. Thus, the zero discharge of the coking wastewater seems to be realized, and a large amount of biochemical drainage and circulating cooling drainage water is directly discharged into the atmospheric environment after being vaporized by the incandescent coke. Therefore, the water consumption of the coking production is increased, the energy consumption of the coking production is also increased, and the atmospheric environmental pollution is also increased.

In recent years, most coking enterprises adopt a dry quenching technology to recover sensible heat in incandescent coke to produce steam or generate electricity. Meanwhile, some coking enterprises adopt reverse osmosis and evaporation technologies to carry out advanced treatment and recycling on biochemical drainage and circulating cooling drainage, but the following problems exist in the process:

firstly, the reverse osmosis membrane is easy to cause organic matter bridging and blocking. The reason is that: the organic matter content and COD in the drainage of the biochemical system are higher, so that the reverse osmosis membrane is blocked due to the accumulation and hanging of the organic matter.

The existing ammonia distillation process has the following defects: firstly, before ammonia distillation, the tar which is in a colloid emulsified state with ammonia water is not removed by adopting an air floatation and ceramic filtration method. And secondly, residual ammonia water containing more tar passes through an ammonia still, remains heavy oil asphalt components with high boiling point, high density, strong viscosity and poor fluidity in distillate, and is easy to deposit, accumulate and hang on an ammonia still tray. Thirdly, the ammonia distillation wastewater carrying the tar pitch is solidified through the heat exchange cooling equipment, so that the heat exchange cooling effect is reduced and even the equipment is blocked, and the production is stopped and the cleaning is frequent. Fourthly, the existing ammonia distillation process with reflux for producing strong ammonia water or strong ammonia steam has poor effect of stripping and fractionating tar carried by residual ammonia water, and the content of nitrogen-containing organic matters such as pyridine, quinoline, indole and the like and polycyclic aromatic hydrocarbon organic matters which are difficult to be biochemically degraded in ammonia distillation wastewater is high. The existing ammonia distillation process has the problems and the defects, so that the ammonia nitrogen and organic matters in the ammonia distillation wastewater have high content and large fluctuation, and the stable operation of a subsequent biochemical system is very unfavorable.

The existing biochemical treatment process has the following defects: one at A/O or A²Before the/O biochemical reaction tank, an air floatation oil removal method is adopted, the removal rate of heavy tar with high density in the ammonia distillation wastewater is low, particularly, tar in a colloid emulsified state of the ammonia distillation wastewater cannot be removed, and even under the stirring of air floatation gas, the content of the tar in the colloid emulsified state with the ammonia distillation wastewater is increased. Two thereof, A/O and A²The biochemical process of the/O is that a large amount of nitrifying liquid discharged from the O tank flows back to the A tank; therefore, the concentration of the activated sludge and the organic matters in the A/O tank can be diluted, the biochemical degradation reaction speed of the organic matters can be reduced, the reaction time can be shortened, the biochemical degradation rate of the organic matters can be correspondingly reduced, and the COD of the drainage water of a biochemical system is increased. Thirdly, in A/O or A²In the biochemical coagulation process of the/O, a large amount of ferrous sulfate and caustic soda are added, so that the sulfate radical and dissolved salt content in biochemical wastewater can be obviously increased. In a word, the biochemical drainage dissolved salt content and COD in the existing biochemical process are high, so that the subsequent reverse osmosis desalination process is very unfavorable.

Secondly, the reverse osmosis membrane is easy to generate calcium magnesium salt scaling blockage. The reason is that: the biochemical drainage contains SO₄ ^＝、F^-And SiO₃ ^＝Plasma, and Ca is contained in the recirculated cooling sewage²⁺And Mg²⁺Cation, both of which are mixed and then passed through a reverse osmosis membrane, easily generates CaF₂、CaSiO₃、CaSO₄And CaCO₃Scale build-up blocks the reverse osmosis membrane.

Thirdly, the reverse osmosis process has low fresh water yield and large concentrated water discharge. The reason is that: reverse osmosis module water inlet dissolved salt and SO₄ ^＝、HCO₃ ^-、CO₃ ^＝、F^-、SiO₃ ^＝/Ca²⁺、Mg²⁺The content of anions and cations is higher. Especially the currently generally adopted flocculation adsorption method or Fenton oxidation method, more ferrous sulfate or aluminum sulfate, sulfuric acid are added into waterAnd caustic soda. To avoid the concentration of anions/cations being greater than the product of their dissolved salts, and to prevent the formation of CaF with very low solubility₂、CaSiO₃、CaCO₃And CaSO₄The scale is separated out to block the reverse osmosis membrane, so that the discharge capacity of reverse osmosis concentrated water is inevitably increased, and the yield of reverse osmosis fresh water is correspondingly reduced.

Fourthly, the coking wastewater treatment and recycling energy consumption is high. The reason is as follows: on one hand, a large amount of steam used for evaporating ammonia from the residual ammonia water is not utilized in multiple effects; on the other hand, a large amount of heat energy is consumed in the evaporation and concentration process of the reverse osmosis concentrated water; in addition, the higher the content of the dissolved salt in the reverse osmosis inlet water is, the higher the reverse osmosis inlet water operation pressure is, and the higher the energy consumption of the corresponding reverse osmosis process is.

In conclusion, in order to reduce the energy consumption and water consumption for coking, meet the requirements of national environmental protection policies, effectively recycle the coking wastewater with lower energy consumption and cost, and practically achieve zero discharge of the coking wastewater, technical integration innovation is urgently needed to make up for and overcome the shortages and the defects of the prior art.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a device and a method for treating coking wastewater, which are used for comprehensively treating coking residual ammonia water, coking production circulating cooling sewage, coking plant area biochemical sewage and floor flushing water, so that all the coking wastewater is recycled, fresh water with the yield of 99% is recycled for a power boiler water supply system and a coking production circulating cooling water system, and concentrated brine separated from the coking wastewater is used for producing caustic soda and mixed acid (hydrochloric acid and sulfuric acid), so that zero discharge of the coking wastewater can be realized with low energy consumption and low cost.

In order to achieve the above purposes, the invention adopts the technical scheme that: an apparatus for treating coking wastewater, the apparatus comprising: an ammonia evaporation and evaporation unit, a Ca/COAOC/Ca treatment unit, a filtration and adsorption unit, a reverse osmosis and electrodialysis unit and a bipolar membrane electrodialysis unit.

Further, the ammonia distillation and evaporation unit comprises: a coarse grained oil/water separation tank, a composite ammonia still, a heavy tar catcher, an ammonia still wastewater heat exchanger, an ammonia still wastewater cooler, a brine positive pressure evaporation unit and a brine negative pressure evaporation unit.

Further, the coarse oil/water separation tank includes: an oil storage chamber, a coarse granulation chamber, a settling chamber, a circulation chamber and a clear liquid chamber; the bottom of the oil storage chamber is provided with a tar discharge port, the inside of the coarse granulation chamber is provided with mesh corrugated packing and a residual ammonia water feeding distributor from top to bottom, the distributor is connected with an oil-containing residual ammonia water inlet, the heavy tar inlet is connected with the lower part of the coarse granulation chamber, the inside of the sedimentation chamber is provided with a corrugated plate packing layer, the upper part of the sedimentation chamber is provided with an annular sawtooth overflow weir, the clear solution chamber is provided with a liquid level meter connector, a clear solution chamber diffusion pipe and a deoiling residual ammonia water clear solution outlet, and is provided with a circulating flow chamber and clear solution chamber communicating pipe and a settling chamber and.

Further, the composite ammonia still comprises a lower section, a middle section and an upper section; the lower section is internally provided with a horn-shaped downcomer and a mesh corrugated collecting layer from bottom to top, and is also provided with an ammonia distillation wastewater outlet, a liquid level meter interface and a steam inlet, the middle section is provided with a plurality of layer plate type mass transfer tower trays, the top layer mass transfer tower tray is provided with a fractionating liquid inlet and an alkali liquid inlet, the upper section is internally provided with a pall ring packing layer, the bottom of the packing layer is provided with a hump support, the top of the packing layer is provided with a feeding distributor, the distributor is connected with a residual ammonia water feeding port, the top of the upper section is provided with an ammonia distillation steam outlet, the lower section and the middle section are provided with a liquid phase collecting broken tower tray, the broken tower tray is provided with a fractionating liquid outlet.

Further, the heavy tar trap includes: a tar collecting chamber, a settling and trapping chamber and a clear liquid chamber; the bottom of the tar collecting chamber is provided with a tar discharging port, the settling and trapping chamber is internally provided with a mesh corrugated trapping layer, a trumpet down-flow pipe and a down-flow pipe fixing rib plate from top to bottom, the trumpet down-flow pipe is connected with a fractional liquid inlet, a clear liquid distribution umbrella cap is arranged in the clear liquid chamber, and the top of the clear liquid chamber is provided with a fractional clear liquid outlet.

Further, the brine positive pressure evaporation unit comprises: the system comprises a brine preheater, a positive pressure evaporator, a positive pressure evaporation heater, a steam condensate collecting tank, a positive pressure evaporation mother liquor circulating pump and a condensate conveying pump which are connected by a process pipeline.

Further, the salt water negative pressure evaporation unit includes: the system comprises a negative pressure evaporation heater, an ammonia condensate cooler, a dilute ammonia water tank, a negative pressure evaporator, an evaporation steam condenser, an evaporation condensate water high-level tank, a negative pressure evaporation mother liquor circulating pump and a vacuum pump which are connected by a process pipeline.

Further, the Ca/COAOC/Ca processing unit comprises: the system comprises a calcium salt/carbon slurry adsorption tank, a primary sedimentation tank, a COAOC biochemical system I, a calcium adding reaction tank, a decalcification reaction tank, a flocculation sedimentation tank and a softened clean water tank which are connected in series in sequence by a process pipeline, and is provided with a calcium salt/carbon slurry/biochemical sludge thickening barrel, a carbon slurry preparation system II, a lime milk preparation system III and an ammonia distillation wastewater/circulating cooling sewage heat exchanger.

Furthermore, the COAOC system I comprises a pre-aeration tank (O), an anoxic tank (A), an aeration tank (O) and a secondary sedimentation tank which are sequentially connected in series and circulate by carbon pulp.

Further, the carbon slurry preparation system II comprises: a small coke particle hoister, a small coke particle storage tank, a belt scale electronic, a wet ball mill, a carbon slurry intermediate tank and a carbon slurry grading tank which are connected by a process pipeline.

Further, the lime milk preparation system III comprises: a CaO storage tank, a CaO adjusting screw feeder, a lime milk preparation tank and a CaO dust collecting water flow ejector which are connected by a process pipeline.

Further, the filtration and adsorption unit comprises: the multi-medium filter, the microporous metal filter, the acidification reactor, the gas/liquid separation tank and the activated carbon adsorption tank which are connected by a process pipeline are sequentially connected in series, and the device comprises a dilute mixed acid tank, a dilute caustic soda tank, a circulating alkali tank, a waste alkali tank, an ultrafiltration sewage tank and a ceramic filtration and back flushing sewage tank.

Further, the reverse osmosis and electrodialysis unit comprises: the system comprises an ultrafiltration water inlet tank, an ultrafiltration pressure pump, an ultrafiltration cartridge filter, an ultrafiltration membrane component, a reverse osmosis water inlet tank, a reverse osmosis pressure pump, a reverse osmosis cartridge filter, a reverse osmosis membrane component and a reverse osmosis fresh water tank which are sequentially connected in series, and an ion exchange resin tower, a first-stage EDR electrodialysis component, a first-stage EDR concentrated water tank, a second-stage EDR feed pump, a second-stage EDR electrodialysis component, a second-stage EDR concentrated water tank, a second-stage EDR concentrated water pump, an activated carbon adsorber and a strong brine intermediate tank which are sequentially connected in; and the fresh water outlet of the first-stage EDR electrodialysis assembly and the fresh water outlet of the second-stage EDR electrodialysis assembly are communicated with the reverse osmosis water inlet pool through a process pipeline.

Further, the bipolar membrane electrodialysis unit comprises: the device comprises a settling barrel, a saline water clear solution tank, an alpha cellulose coating filter, an ion exchange resin tower, a Bipolar Membrane Electrodialysis (BMED) component and a saline water circulating tank which are connected in series in sequence, wherein the settling barrel, the saline water clear solution tank, the alpha cellulose coating filter, the ion exchange resin tower, the BMED component and the saline water circulating tank are connected in series in sequence, and the settling barrel, the saline water clear solution tank, the BMED component and the.

In order to achieve the above purposes, the invention adopts the technical scheme that: a method of treating a coking wastewater treatment plant, the method comprising:

(1) deoiling and distilling the residual coking ammonia water through a granular oil/water separation tank, a composite ammonia still and a heavy tar catcher respectively to obtain ammonia distillation wastewater; (2) cooling part of the ammonia distillation wastewater by an ammonia distillation wastewater heat exchanger and an ammonia distillation wastewater cooler, and sequentially performing adsorption and deoiling, COAOC biochemical processes, calcium adding reaction, decalcification reaction, flocculation reaction and flocculation precipitation by a Ca/COAOC/Ca unit to obtain softened water; (3) filtering the softened water obtained in the step (2) by a filtering and adsorbing unit sequentially through multi-medium filtering, microporous metal filtering, acidification reaction, gas/liquid separation and activated carbon adsorption purification to obtain filtered, adsorbed and purified water; adsorbing and draining water by using activated carbon, and adding a proper amount of alkali to control the pH value to be 7-7.5; (4) and (3) carrying out ultrafiltration and reverse osmosis light/concentration separation on the filtered and adsorbed purified water obtained in the step (3), adding a proper amount of caustic soda into reverse osmosis concentrated water to control the pH value to be 7.5-8, removing divalent cations such as calcium/magnesium/iron/manganese in the water through ion exchange resin, and carrying out electrodialysis light/concentration separation.

Further, the deoiling in the step (1) specifically comprises: the coking residual ammonia water is sequentially subjected to coarse graining sedimentation and trapping, steam stripping and fractionation at the upper section of a compound ammonia still, gravity sedimentation and trapping, steam stripping and fractionation at the middle section of the compound ammonia still and gravity sedimentation and trapping and deoiling at the lower section of the compound ammonia still, heavy tar in the residual ammonia water is removed through three times of sedimentation and trapping, and light tar in the residual ammonia water is removed through two times of steam stripping and fractionation

Further, the ammonia distillation in the step (1) specifically comprises: the brine evaporation steam discharged by the brine positive pressure evaporation unit is used as a heat source, and the residual ammonia water is subjected to twice steam stripping and ammonia distillation through the upper section and the middle section of the composite ammonia distillation tower.

Further, the adsorption deoiling in the step (2) comprises the following steps: calcium salt sludge produced by flocculation precipitation and carbon slurry biochemical sludge produced in the COAOC process are utilized to adsorb and remove emulsified tar in ammonia distillation wastewater.

Further, the COAOC biochemical process in the step (2) comprises the following steps: and (2) making small-particle coke with the particle size of 3-5 mm into carbon slurry with the particle size of 0.05-0.1 mm and the water content of 40-60% by using a carbon slurry preparation system II through a wet grinding machine, adding the carbon slurry into an aeration tank (O) of a COAOC system as an activated biochemical sludge and organic matter biochemical degradation adsorption catalysis carrier, and circulating the carbon slurry among a pre-aeration tank (O), an anoxic tank (A), the aeration tank (O) and a secondary sedimentation tank of the COAOC system.

Further, the method in the step (3) further comprises the following steps of washing and regenerating the activated carbon adsorption bed: and (2) cooling the rest part of the ammonia evaporation wastewater in the step (1) to 90-95 ℃ through an ammonia evaporation wastewater heat exchanger, heating the caustic soda water solution with the sodium hydroxide content of 15-20% to 80-85 ℃, and washing and regenerating the activated carbon adsorption bed by using hot alkali liquor.

Further, the step (1) further comprises: and (4) adding mixed acid (hydrochloric acid and sulfuric acid) into the concentrated brine separated by the electrodialysis in the step (4), controlling the pH value to be 4-5, adsorbing and purifying by using activated carbon, adding caustic soda, controlling the pH value to be 8-8.5, and performing evaporation concentration by using a brine positive pressure evaporation unit and a brine negative pressure evaporation unit to obtain evaporation concentration brine.

Further, the method also comprises a step (5) of producing caustic soda and mixed acid (hydrochloric acid + sulfuric acid) by a bipolar membrane electrodialysis unit, and specifically comprises the following steps: adding caustic soda into the evaporated and concentrated brine, and controlling the pH value to be 9-10; sequentially passing through a dalton settling barrel, an alpha cellulose coating filter and an ion exchange resin tower to remove suspended matters and divalent cations such as calcium, magnesium, iron, manganese and the like in the brine; and adding mixed acid, controlling the pH value of the concentrated brine to be 6.5-7, and producing caustic soda and mixed acid (hydrochloric acid and sulfuric acid) through a bipolar membrane electrodialysis assembly.

Further, the step (1) of subjecting the electrodialysis concentrated water to two-stage evaporation and concentration by a brine positive pressure evaporation unit and a brine negative pressure evaporation unit to obtain the concentrated brine specifically comprises: carrying out primary evaporation concentration on the electrodialysis concentrated water by using primary steam as a heat source through a saline water positive pressure evaporation unit; and (3) taking the oily ammonia-containing steam escaping from the top of the composite ammonia still as a heat source, and continuously evaporating and concentrating the first-stage evaporated strong brine through a brine negative pressure evaporation unit to obtain the strong brine.

The invention has the effects that the coking residual ammonia water, the coking production circulating cooling sewage, the coking plant area biochemical sewage and the floor flushing water are comprehensively treated, all the coking residual ammonia water, the coking production circulating cooling sewage, the coking plant area biochemical sewage and the floor flushing water are recycled, fresh water with the yield of 99% is reused for a power boiler water supply system and a coking production circulating cooling water system, and concentrated brine separated from coking wastewater is used for producing caustic soda and mixed acid (hydrochloric acid and sulfuric acid), so that zero discharge of coking wastewater can be realized with low energy consumption and low cost.

Drawings

FIG. 1 is a view showing the construction of a coking wastewater treatment apparatus according to the present invention

① coking residual ammonia water + non-reflux ammonia distillation condensate, ② EDR electrodialysis discharge strong brine, ③ 0.6.6 MPa primary steam, ④ 40 ℃ ammonia distillation wastewater, ⑤ 90 ℃ ammonia distillation wastewater, ⑥ primary steam and brine evaporation condensate water, ⑦ evaporation concentrated brine, ⑧ dilute ammonia water, ⑨ coking plant terrace flushing and domestic sewage, ⑩ coking production circulating cooling sewage,

the coke of small-sized grains is formed,

the powdery CaO is added into the raw materials of the coke,

the sodium carbonate is prepared from sodium carbonate, sodium hydroxide,

the biochemical treatment and the softening of the drained water,

calcium salt/carbon slurry/biochemical sludge thick slurry,

the water is discharged in the filtering and adsorbing process,

the reverse osmosis desalinization fresh water is carried out,

the concentrated water is treated by ultrafiltration,

filtering and adsorbing the backflushing sewage,

the dilute alkali produced in the double-membrane electrodialysis procedure,

the filtering and adsorbing process uses dilute alkali,

the reverse osmosis and electrodialysis processes use dilute alkali,

the biochemical and softening process uses waste alkali,

the residual ammonia water is used as waste alkali for ammonia distillation,

the mixed acid produced in the double-membrane electrodialysis procedure,

mixed acid for filtering and adsorbing process，

The mixed acid for reverse osmosis and electrodialysis is used,

the mixed acid is sold for the outside, and the mixed acid is sold for the outside,

the ion exchange resin is used for regenerating the waste water,

the precipitated mud and the ion exchange resin regenerate the waste water,

the content of tar oil,

sodium polyacrylate;

FIG. 2 is a schematic diagram of the structure of an ammonia distillation and evaporation unit in the device;

FIG. 3 is a schematic diagram of the Ca/COAOC/Ca processing unit in the device;

FIG. 4 is a schematic view of the structure of the filtration and adsorption unit of the present apparatus;

FIG. 5 is a schematic diagram of the structure of a reverse osmosis unit and an electrodialysis unit in the device;

FIG. 6 is a schematic diagram of the structure of a bipolar membrane electrodialysis unit in the device;

FIG. 7 is a schematic structural diagram of a coarse-grained precipitation oil/water separation tank in the ammonia distillation and evaporation unit;

FIG. 8 is a schematic diagram of a heavy tar trap in the ammonia distillation and evaporation unit;

FIG. 9 is a diagram of a combined ammonia still in an ammonia still and evaporation unit.

In the figure: 100-ammonia distillation and evaporation unit; 200-Ca/COAOC/Ca treatment units; 300-filtration and adsorption unit; 400-reverse osmosis and electrodialysis unit; 500-a bipolar membrane electrodialysis unit; 101-coarse graining settling oil/water separation tank; 102-a composite ammonia still; 103-heavy tar trap; 104-ammonia distillation wastewater heat exchanger; 105-ammonia distillation wastewater cooler; 106-saline water positive pressure evaporator set; 107-saline water negative pressure evaporation unit; 1061-brine preheater; 1062-positive pressure evaporator; 1063-positive pressure evaporation heater; 1064 a steam condensate collection tank; 1065-positive pressure evaporation mother liquor circulating pump; 1066-condensate water transfer pump; 1071-negative pressure evaporation heater; 1072-dilute ammonia water cooler; 1073-dilute ammonia water tank; 1074-negative pressure evaporator; 1075-negative pressure evaporative vapor condenser; 1076-evaporating the condensed water under negative pressure to put the trough high; 1077-negative pressure evaporation mother liquor circulating pump; 1078-vacuum pump; 201-calcium salt/carbon slurry adsorption tank; 202-primary sedimentation tank; 203-pre-aeration tank (O); 204-anoxic tank (a); 205-aeration tank (O); 206-secondary sedimentation tank; 207-calcium adding reaction tank; 208-decalcification reaction tank; 209-flocculation reaction tank; 210-a flocculation sedimentation tank; 211-softening the clean water tank; 212-calcium salt/carbon slurry/biochemical sludge slurry thickening barrel; 213-small coke hoist; 214-small coke storage tank; 215-belt electronic scale; 216-wet ball mill; 217-carbon slurry intermediate tank; 218-a carbon slurry grading tank; 219-CaO powder storage tank; 220-CaO adjustable screw feeder; 221-lime milk preparation tank; a 222-CaO dust trapping water flow ejector; 223-ammonia distillation wastewater/circulating cooling sewage heat exchanger; 301-a multimedia filter; 302-a microporous metal filter; 303-an acidification reactor; 304-a gas/liquid separation tank; 305-an activated carbon adsorption tank; 306-dilute acid mixing tank; 307-dilute caustic soda groove; 308-circulating alkali tank; 309-waste alkali groove; 310-ultrafiltration concentrated water tank; 311-microporous metal filtration concentrated water and backflushing sewage tank; 401-ultrafiltration water intake pool; 402-ultrafiltration booster pump; 403-ultrafiltration cartridge filter; 404-an ultrafiltration membrane module; 405-a reverse osmosis water inlet tank; 406-a reverse osmosis booster pump; 407-reverse osmosis cartridge filter; 408-a reverse osmosis membrane module; 409-a reverse osmosis fresh water pool; 410-an ion exchange resin column; 411-a primary EDR electrodialysis stack; 412-first EDR concentrate tank; 413-secondary EDR feed pump; 414-secondary EDR electrodialysis stack; 415-second EDR concentrated water pool; 416-two-stage EDR concentrate pump; 417-activated carbon adsorber; 418-strong brine intermediate tank; 501 Dalton settling barrel; 502-saline solution tank; 503-alpha cellulose coated filters; 504-ion exchange resin column; 505-a bipolar membrane electrodialysis unit; 506-brine circulation tank; 507-mixed acid product tank; 508-dilute alkali product tank; 509-sludge settling and resin regeneration sewage tank; 10101-tar discharge; 10102 oil-containing residual ammonia water inlet; 10103 clean liquid chamber level meter interface; 10104 a clear liquid chamber discharge port; 10105 corrugated plate packing layer; 10106 a sedimentation and circulation chamber diffusing pipe; 10107 ring-shaped sawtooth overflow weir; 10108 the circulation chamber is communicated with the clear liquid chamber; 10109 mesh corrugated packing layer; 10110 feeding distributor of residual ammonia water; 10111 heavy tar inlet; 10112 an outlet for the clear liquid of the deoiled residual ammonia water; 10113-oil reservoir; 10114-oil droplet coarse graining chamber; 10115-tar settling chamber; 10116-circulation chamber; 10117-a clear liquid chamber; 10301-discharge port for heavy tar containing water; 10302-downcomer fixing rib plate; 10303-a flared downcomer; 10304-oil-containing distillate inlet; 10305-mesh corrugated trap layer; 10306-umbrella hat annular flow plate; 10307-deoiled fraction outlet; 10308-has an oil reservoir; 10309-a settling capture chamber; 10310-a clear liquid chamber; 10201-heavy oil discharge; 10202-ammonia distillation wastewater outlet; 10203-level gauge interface; 10204-steam inlet; 10205-fraction inlet; 10206-distillate outlet; 10207-residual aqueous ammonia feed; 10208-Ammonia still vapor outlet; 10209 — feed distributor; 10210-packing with pall ring packing; 10211-Bohr ring packing hump support; 10212-liquid phase collection tray; 10213-lye inlet; 10214-mass transfer trays; 10215-communicating tube; 10216 is provided with a mesh corrugated trap layer; 10217-and trumpet downcomers.

Detailed Description

In order to make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be further described in detail with reference to the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The coking wastewater treatment device provided by the invention is shown in figure 1 and comprises: there are an ammonia still and evaporation unit 100, a Ca/coaac/Ca treatment unit 200, a filtration and adsorption unit 300, a reverse osmosis and electrodialysis unit 400, and a bipolar membrane electrodialysis unit 500.

With particular construction of the ammonia still and evaporation unit 100, as shown in FIG. 2The method comprises the following steps: a coarse graining sedimentation oil/water separation tank 101, a composite ammonia still 102, a heavy tar catcher 103, an ammonia still wastewater heat exchanger 104, an ammonia still wastewater cooler 105, a saline water positive pressure evaporator set 106 and a saline water negative pressure evaporator set 107, and

and forming the process pipeline connection.

Wherein, the brine positive pressure evaporator set 106: the system comprises a brine preheater 1061, a brine positive pressure evaporator 1062, a positive pressure evaporation heater 1063, a steam condensate water tank 1064, a positive pressure evaporation mother liquor circulating pump 1065, a condensate water conveying pump 1066 and the like, which are connected with process pipelines.

Wherein, the saline water negative pressure evaporation unit 107: negative pressure evaporation heater 1071, dilute ammonia water cooler 1072, dilute ammonia water tank 1073, negative pressure evaporator 1074, negative pressure evaporation steam condenser 1075, negative pressure evaporation condensate water high-level tank 1076, negative pressure evaporation mother liquor circulating pump 1077, vacuum pump 1078, and the relevant process pipeline connection forms.

The coarse oil/water separation tank 101 is configured as shown in fig. 7: the device comprises an oil storage chamber 10113, a coarse graining chamber 10114, a settling chamber 10115, a circulation chamber 10116 and a clear liquid chamber 10117, and specifically comprises a tar discharge port 10101, an oil-containing residual ammonia water inlet 10102, a clear liquid chamber level meter interface 10103, a clear liquid chamber diffusing pipe 10104, a corrugated plate packing layer 10105, a settling chamber and circulation chamber diffusing pipe 10106, an annular sawtooth overflow weir 10107, a circulation chamber and clear liquid chamber communicating pipe 10108, a mesh corrugated packing layer 10109, a residual ammonia water feeding distributor 10110, a heavy tar inlet 10111, a deoiling residual ammonia water clear liquid outlet 10112 and other parts.

It should be noted that the corrugated plate packing layer 10105 may be any one of mesh corrugated packing, steel wire mesh packing, steel plate mesh packing, labyrinth steel plate packing, and small coke, as required.

The heavy tar trap 103 has a structure as shown in fig. 8: the device consists of a tar collecting chamber 10308, a settling and trapping chamber 10309 and a clear liquid chamber 10310, and comprises a tar discharge port 1031, a downcomer fixing rib plate 1032, a trumpet downcomer 1033, a fractional liquid inlet 1034, a mesh corrugated trapping layer 1035, a clear liquid distribution umbrella cap 1036, a fractional clear liquid outlet 1037 and the like.

Wherein, the structure of the composite ammonia still 102 is shown in fig. 9: consists of a lower section, a middle section and an upper section; the lower section is provided with a mesh corrugated collecting layer 10216 which comprises a heavy oil discharge port 10201, a steam inlet 10204, a liquid level meter interface 10203, an ammonia distillation wastewater outlet 10202, a horn-shaped down-flow pipe 10217 and other parts; the middle section is provided with a plurality of layers of plate-type mass transfer trays 10214 and parts such as a fractional liquid inlet 10205, an alkali liquor inlet 10213 and the like; the upper section is provided with a pall ring packing layer 10210 and is provided with a residual ammonia water feed inlet 10207, a feed distributor 10209, a fractional liquid outlet 10206, an ammonia distillation steam outlet 10208, a pall ring packing hump support 10211 and other parts; a liquid phase collecting tower breaking tray 10212 is arranged between the lower section and the middle section; a communicating pipe 10215 is arranged between the downcomer of the bottom tray at the bottom of the middle section and the trumpet-shaped downcomer at the bottom in the lower section.

The method for treating wastewater in the ammonia distillation and evaporation unit 100 comprises the following steps: the method comprises the steps of conveying the residual ammonia water containing oil from a gas primary cooling system into a feeding distributor of a coarse-grained settling oil/water separation tank 101 through a pipeline, enabling the residual ammonia water to form a dispersed phase, enabling the dispersed phase to pass through a coarse-grained chamber filled with mesh corrugated fillers from bottom to top, enabling the dispersed phase to be in close contact with tar in a continuous phase, enabling the fine tar drops suspended in water to be partially adsorbed by the tar in the continuous phase, enabling the fine tar drops to be partially aggregated into large tar drops through coarse graining, then passing through a settling chamber filled with corrugated plates from bottom to top, enabling the large tar drops to have a high settling speed, falling onto the corrugated plates of the settling chamber within a short time, forming larger tar drops, then falling into the coarse-grained chamber, forming a tar continuous phase to flow into an oil storage chamber of the tank, and finally discharging and recycling the tar continuous phase through the.

Residual ammonia water extracted from a clear solution chamber of the coarse-grained settling oil/water separation tank 101 still contains tiny tar drops in an emulsified colloid state with the ammonia water, the residual ammonia water is sent to an ammonia evaporation wastewater heat exchanger 104 through a pipeline, the residual ammonia water is sent to the upper section of a composite ammonia evaporation tower 102 through a pipeline after exchanging heat with ammonia evaporation wastewater from the pipeline, pall ring packing which is difficult to be blocked by tar hanging materials, has small resistance and large flux is arranged on the upper section of the tower, and hydrogen sulfide, hydrogen cyanide and most of free ammonia in the residual ammonia water are stripped and removed by utilizing ammonia evaporation steam escaping from the middle section of the tower through a pall ring packing layer; meanwhile, the tiny tar drops in the residual ammonia water are stripped and fractionated, wherein organic matters with small molecules and low boiling points are stripped into a vapor phase and escape from the top of the ammonia still along with ammonia still, and heavy tar which is large in molecules, high in boiling points, high in density and high in viscosity and easy to aggregate and precipitate still remains in a liquid phase.

The upper-section distillate is completely extracted from a liquid phase collecting tray 10212 of the composite ammonia distillation tower, flows into a heavy tar catcher 103 through a pipeline, continuously extracts heavy tar containing a proper amount of water from the bottom of the heavy tar catcher 10, continuously flows into an oil storage chamber 10113 of a coarse-grained settling oil/water separation tank 101 through a pipeline, is mixed with tar with low viscosity and good fluidity separated from the residual ammonia water, and is finally periodically discharged and recovered through the pipeline and the ear.

The upper-section distillate overflowing from the top of the heavy tar catcher 103 is sent to the top of the middle section of the compound ammonia still 102 through a pipeline ⑤, and the evaporation steam escaping from the top of the saline water positive pressure evaporation unit I107 is sent to the top of the middle section of the compound ammonia still 102 through a pipeline

Feeding the distillate into the bottom of the middle section of the composite ammonia still 102, and continuously stripping and distilling ammonia from the distillate of the upper section through a plurality of layers of mass transfer trays 10214 of the middle section; at the same time, in order to decompose and remove the fixed ammonium salt in the distillate, an appropriate amount of waste lye from the filtration and adsorption process is passed through the pipeline

Sending the wastewater into the middle section of a composite ammonia still 102, and controlling the pH value of the ammonia still wastewater to be 8-8.5.

The ammonia distillation wastewater flowing out of the middle-section bottom tray of the composite ammonia distillation tower 102 flows into the lower section of the composite ammonia distillation tower through a liquid guide pipe outside the composite ammonia distillation tower 102, is subjected to sedimentation, trapping, separation and removal of ammonia distillation wastewater with tar pitch, is sent into an ammonia distillation wastewater heat exchanger 104 through a pipeline and is divided into two streams after heat exchange with the residual ammonia water: one strand of ammonia evaporation wastewater cooled to 40 ℃ by the ammonia evaporation wastewater cooler 105 is sent to the Ca/COAOC/Ca unit 200 for treatment through a pipeline (a) (+). And the other ammonia distillation wastewater with the temperature of 90-95 ℃ is sent to the filtering and adsorbing unit 300 through a pipeline for heating the activated carbon adsorption bed to regenerate and circularly wash the alkali liquor, and then is sent to the Ca/COAOC/Ca unit 200 for treatment.

By the brine positive pressure evaporator set 106: the salt water from the reverse osmosis and electrodialysis unit 400 with a pH value of 8-8.5 is firstly passed through a pipeline

Sent to a brine preheater 1061 and then is further piped

Feeding into a positive pressure evaporator 1062, and introducing steam of 0.6MPa or more via pipeline

And introducing a positive pressure evaporation heater 1063 to provide heat for the brine positive pressure evaporation unit I, and preheating brine from the reverse osmosis and electrodialysis unit 400 by using steam condensate water with higher temperature flowing out of the heater 11063 through a brine preheater 1061. The steam condensate water flowing out of the brine preheater 1061 is passed through a pipeline

Flows into a steam condensate collection tank 11064; 108-110 ℃ evaporation steam escapes from the top of the positive pressure evaporator 1062 through a pipeline

Sent into a composite ammonia still 102 for stripping and deamination of residual ammonia water and fractionation of tar. The evaporated mother liquor pumped out by a positive pressure evaporated mother liquor circulating pump 1065 from the bottom of the positive pressure evaporator 1062 is mostly fed into a pipeline

Forced circulation passes through the positive pressure evaporation heater 1063 at a high speed and flows back to the positive pressure evaporator 1062, and the rest passes through a pipeline

Sent to a saline water negative pressure evaporation unit 107.

By the saline water negative pressure evaporation unit 107: the saline water discharged by the positive pressure evaporation unit is treated by a pipeline

Sending the ammonia gas into a negative pressure evaporator 1074, continuing to evaporate and concentrate the ammonia gas under the negative pressure condition, and utilizing the ammonia steam with the temperature of 101-103 ℃ escaping from the top of the composite ammonia still 102 to pass through a pipeline

And the water is sent to a negative pressure evaporation heater 1071 to provide heat for the saline water negative pressure evaporation unit 107. At the same time, the ammonia vapor is condensed into dilute ammonia water through the pipeline

Cooled to 40 ℃ by a dilute ammonia water cooler 1072 and then is cooled by a pipeline

Flows into a dilute ammonia storage tank 1073. Finally, dilute ammonia water containing hydrogen sulfide, hydrogen cyanide and light tar components of pyridine, quinoline, indole, naphthalene, methylnaphthalene, biphenyl and anthracene is passed through pipeline

Sending the gas into a gas pre-cooling tower before desulfurization, wherein ammonia, hydrogen sulfide and hydrogen cyanide are taken away by the gas for recovery, and light tar components are sent into a gas primary cooling tar/ammonia water separation system along with the gas pre-cooling liquid for recovery. The evaporation steam escaping from the top of the negative pressure evaporator 1074 is passed through the pipeline

Condensed by a condenser 1075 and then passed through a pipeline

Flows into a negative pressure evaporation condensate water high-level tank 1076 and is communicated with a pipeline

Flows into a steam condensate collecting tank 1064 of the brine positive pressure evaporation unit 106, and finally, the brine negative pressure evaporation condensate and the positive pressure evaporation heat the steam condensate through pipelines

Sent to a boiler water supply system or a coking production circulating cooling water system for recycling. Evaporating mother liquor pumped by a negative pressure evaporating mother liquor circulating pump 1077 from the bottom of the saline water negative pressure evaporator 1074 is largely circulated through a pipeline

The liquid passes through the negative pressure evaporation heater 1071 at high speed and flows back to the negative pressure evaporator 1074, and the rest flows through the pipeline

Sent to the bipolar membrane electrodialysis unit 500 for the production of caustic soda and hydrochloric acid. Meanwhile, the vacuum pump 1078 is used for pumping the negative pressure evaporation condensation water high-level tank 1076, the negative pressure evaporator 1074 and the associated equipment into negative pressure, and the temperature of the brine negative pressure evaporation circulation mother liquor is controlled at 65 ℃. In addition, the salt-containing reflux liquid from the bipolar membrane electrodialysis unit 500 is passed through a pipeline

Sent to a negative pressure evaporator 1074 to be repeatedly evaporated and concentrated.

In summary, the technical features of the above steps: firstly, sequentially passing through a coarse grained oil/water separation tank, an upper section of a composite ammonia still, a heavy tar catcher, a middle section and a lower section of the composite ammonia still, and performing three-stage sedimentation, twice steam stripping, fractionation, deoiling and ammonia distillation on coking residual ammonia water; therefore, the method can effectively recover light/heavy tar in the residual ammonia water, particularly can reduce the deposition of the heavy tar on the ammonia distillation tray, can avoid the blockage of the ammonia distillation heat exchange cooling equipment by the tar pitch, and can ensure the long-term stable operation of the residual ammonia water ammonia distillation system. Secondly, fresh steam with pressure of more than 0.6MPa is utilized in three ways: the first effect is that fresh steam with pressure of more than 0.6MPa is utilized to provide heat for a brine positive pressure evaporation unit and evaporate and concentrate brine from reverse osmosis and electrodialysis processes; performing second effect, namely performing steam stripping and ammonia distillation on the residual ammonia water through a composite ammonia distillation tower by using the 108-110 ℃ steam of the brine positive pressure evaporation unit; and thirdly, utilizing the ammonia-containing oil-containing steam with the temperature of 101-103 ℃ escaping from the composite ammonia distillation top to provide heat for the brine negative pressure evaporation unit and continuously evaporating and concentrating the evaporated and concentrated brine discharged by the brine positive pressure evaporation unit. The key point of realizing zero discharge of the coking wastewater is low energy consumption and low cost. Thirdly, under the alkaline condition that the pH value is more than 7, the brine is evaporated and concentrated so as to inhibit the corrosion of chloride ions to evaporation equipment. Fourthly, adopting an upper-section filler/middle-section plate/lower-section sedimentation trapping three-section composite tower and a tower top non-reflux method to steam the residual ammonia water by stripping. Therefore, the ammonia distillation wastewater can be prevented from carrying tar pitch, and the long-term stable operation of the ammonia distillation device is facilitated; can obviously reduce the content of ammonia nitrogen, sulfide, cyanide and organic matters and COD in the ammonia distillation wastewater, and is beneficial to the stable operation of a biochemical system and the reduction of biochemical drainage COD. Fifthly, feeding a proper amount of waste alkali from the filtering and adsorbing process into the middle section of the composite ammonia still, and controlling the pH value of the ammonia still wastewater to be 8-8.5. Therefore, while the fixed ammonia in the residual ammonia water is decomposed and removed, the organic matters with good water solubility brought by the waste alkali can be brought out by the ammonia distillation wastewater and finally removed through biochemical degradation. Sixthly, sending the dilute ammonia water generated by ammonia distillation without backflow into a pre-cooling tower before gas desulfurization. Thus, ammonia in the dilute ammonia water is carried out by the precooled gas and then sequentially passes through the ammonia desulfurization tower and the ammonium sulfate saturator, so that ammonia can be supplemented for the gas desulfurization system to improve the desulfurization efficiency, and the ammonia is finally recovered to produce an ammonium sulfate product; meanwhile, light tar components in the dilute ammonia water enter a coal gas primary cooling tar/ammonia water separation system along with the coal gas precooling liquid to be recycled, and negative effects on coal gas desulfurization and ammonium sulfate production are avoided.

Particularly, in the process of stripping and distilling ammonia from residual ammonia water, brine from a reverse osmosis unit and an electrodialysis unit is subjected to two-stage evaporation concentration, the concentrated solution contains about 20% of sodium chloride and a small amount of sodium sulfate, and can be used for producing caustic soda and hydrochloric acid (containing a small amount of sulfuric acid) through a bipolar membrane electrodialysis process so as to realize resource utilization and lay a foundation for realizing zero discharge of coking wastewater.

The structure of the Ca/COAOC/Ca processing unit 200 is shown in FIG. 3, and specifically comprises: comprises a calcium salt/carbon slurry adsorption tank 201, a primary sedimentation tank 202, a COAOC biochemical system I, a calcium adding reaction tank 207, a decalcification reaction tank 208, a flocculation reaction tank 209, a flocculation sedimentation tank 210 and a softened clean water tank 211 which are sequentially connected in series, and also comprises a calcium salt/carbon slurry/biochemical mud thickening barrel 212, a carbon slurry preparation system II, a lime milk preparation system III, an ammonia evaporation wastewater/circulating cooling sewage heat exchanger 23 and a heat exchanger

The related pipelines are connected.

Wherein, COAOC system I: the pre-aeration tank (O)203, the anoxic tank (A)204, the aeration tank (O)205 and the secondary sedimentation tank 206 are connected in series in sequence.

Wherein, the carbon slurry preparation system II is formed by connecting equipment such as a small coke particle hoister 213, a small coke particle storage tank 214, a belt electronic scale 215, a wet ball mill 216, a carbon slurry intermediate tank 217, a carbon slurry grading tank 218 and the like with a process pipeline.

Wherein, lime cream preparation system III: the system is composed of a CaO storage tank 219, a CaO adjusting screw feeder 220, a lime cream preparation tank 221, a CaO dust collecting water jet ejector 222, and the like, and is connected to a process line.

The wastewater treatment method in the Ca/COAOC/Ca treatment unit 200 comprises feeding ammonia evaporation wastewater from a filtering and adsorbing unit 30085 ℃ into an ammonia evaporation wastewater/circulating cooling sewage heat exchanger 223 through a pipeline ⑥ to be cooled to 40 ℃, mixing the ammonia evaporation wastewater from the ammonia evaporation and evaporating unit 100 through a pipeline ① at 40 ℃, passing the mixture through a calcium salt carbon slurry adsorption tank 201 and a sedimentation tank 202 in front of a COAOC biochemical system I, and adsorbing and removing emulsified tar in the ammonia evaporation wastewater by using calcium salt/carbon slurry biochemical sludge

Calcium salt slurry from the flocculation sedimentation tank 210 and pipeline

From twoThe carbon slurry/biochemical sludge in the sedimentation tank 206 is sent to the calcium salt/carbon slurry adsorption tank 201; at the same time, most of the calcium salt/carbon slurry/biochemical sludge extracted from the primary sedimentation tank 202 passes through the pipeline

Circulating between the calcium salt/carbon slurry adsorption tank 201 and the primary sedimentation tank 202, and passing the rest through the pipeline

Feeding into calcium salt/carbon slurry/biochemical sludge thickening barrel 212; clear liquid overflowing from the top of the calcium salt/carbon slurry/biochemical sludge slurry thickening barrel 212 is led to pass through a pipeline

Flows into a calcium salt mud adsorption tank 201; calcium salt/carbon slurry/biochemical sludge extracted from the bottom of the calcium salt/carbon slurry/biochemical sludge thickening barrel 212 is used as dust suppression covering agent and is led to a pipeline

Spraying the mixture on a coking coal pile, and finally using the mixture for coking production.

The ammonia distillation wastewater overflowed from the primary sedimentation tank 202 sequentially passes through a pre-aeration tank (0)203, an anoxic tank (A)204, an aeration tank (0)205 and a secondary sedimentation tank 206 of a COAOC biochemical system, meanwhile, the floor flushing and domestic sewage of a coking plant area are sent into the anoxic tank (A)204 through a pipeline ③, and a proper amount of carbon slurry with the particle size of 0.05-0.1 mm and the water content of 60 percent is sent into the anoxic tank (A)204 through a pipeline

Feeding into an aeration tank (O) 205; the carbon slurry/biochemical sludge withdrawn from the secondary sedimentation tank 206 is divided into four paths: the first path is a pipeline

Flows back to the aeration tank (0)205, and the second path is through a pipeline

Flows back to the anoxic tank (A)204, and the third path passes through the pipeline

Flows back to the pre-aeration tank (O)203, and the fourth path is through a pipeline

Sending the calcium salt carbon slurry into a calcium salt carbon slurry adsorption tank 201 before a COAOC biochemical system.

The so-called COAOC biochemical system is that small coke particles are made into carbon slurry which is used as an adsorption carrier of activated sludge and macromolecular organic matters and is circulated in an OAO biochemical reaction tank. Thus, the biochemical degradation speed of the organic matters is obviously improved.

Pre-exposure pool (0)203 by COAOC system: macromolecular organic matters in the ammonia distillation wastewater and activated sludge in the pre-aeration tank are adsorbed by the carbon slurry, and anaerobic, anoxic and aerobic biochemical reactions occur in sequence from inside to outside in the C particle adsorption layer; meanwhile, sodium sulfide, sodium cyanide, sodium thiocyanate and other sulfur-containing and nitrogen-containing compounds in the ammonia distillation wastewater are subjected to oxidation hydrolysis reaction to generate sulfate, carbonate and ammonia nitrogen, and then the ammonia nitrogen is subjected to nitration reaction to be converted into nitro nitrogen. Therefore, the pre-aeration tank is aerated by blowing air, a proper amount of waste alkali from filtering and adsorption is added into the pre-aeration tank through a pipeline II to neutralize acid generated by biochemical reaction, and the pH value of effluent of the pre-aeration tank is controlled to be 7.5-8.

Anoxic tank by COAOC system (a) 204: under the adsorption catalysis of anaerobic bacteria and carbon slurry, nitrogen-containing organic matters such as pyridine, quinoline and indole in the wastewater can undergo anoxic hydrolysis reaction to generate micromolecular organic matters and ammonia nitrogen [ NH ]₃]And [ C ] in small molecular organic substances]、[H]Element and [ NH ]₃]As a reducing agent, the nitro nitrogen in the drainage water of the pre-aeration tank (0) is removed through denitrification reaction. In addition, in order to prevent the biochemical sludge and the carbon slurry from precipitating, the mechanical stirring of the anoxic tank should be strengthened or the nitrogen gas should be introduced to strengthen the stirring.

Aeration tank (O)205 by COAOC system: under the adsorption and catalysis of the aerobic bacteria and the carbon slurry, the organic matters in the drainage water of the anoxic pond (A) are continuously oxidized and degraded. Therefore, the aeration tank is aerated by blowing air, and a proper amount of waste alkali liquor from filtration and adsorption is added into the aeration tank through a pipeline IV, and the pH value of effluent is controlled to be 7.5-8.

Effluent of a secondary sedimentation tank of the COAOC system sequentially passes through a calcium adding reaction tank 207, a decalcification reaction tank 208, a flocculation reaction tank 209, a flocculation sedimentation tank 210 and a softened clean water tank 211; meanwhile, the circulating cooling sewage is subjected to heat exchange with the filtered and adsorbed ammonia distillation wastewater through a pipeline (a fifth step) by an ammonia distillation wastewater/circulating cooling sewage heat exchanger (223) and the circulating cooling sewage heated to 35-40 ℃ is sequentially subjected to a decalcification reaction tank (208), a flocculation reaction tank (209), a flocculation sedimentation tank (210) and a softened clean water tank (211).

Through a calcium adding reaction tank 207 via a pipeline

Adding a proper amount of lime milk, controlling the pH value of effluent to be 9-9.5, carrying out blast aeration stirring, and carrying out NaHCO (NaHCO) aeration stirring on biochemical effluent₃、NaF、SiO₂、FeSO₄And MnSO₄And (3) the soluble substances and the lime milk react with each other:

NaHCO₃+Ca(OH)₂→CaCO₃↓+NaOH+H₂O；2NaF+Ca(OH)₂→CaF₂↓+2NaOH；

SiO₂+Ca(OH)₂→CaSiO₃↓+H₂O；FeSO₄+Ca(OH)₂→Fe(OH)₂↓+CaSO₄；

MnSO₄+Ca(OH)₂→Mn(OH)₂↓+CaSO₄

some acidic organic substances and Ca (OH) dissolved in biochemical wastewater₂Reacting to generate organic acid calcium precipitate.

It can be seen from this that: by calcium adding reaction, HCO in biochemical wastewater can be effectively removed₃ ^-、F^-/Fe²⁺、Mn²⁺Plasma anion and cation and SiO₂A colloid; especially NaHCO in biochemical drainage₃High content of CaCO produced by calcium addition reaction₃The crystal has large specific surface area and strong adsorption capacity, and can effectively adsorb and remove organic colloidal suspended matters in biochemical wastewater; simultaneously, NaOH generated by calcium addition reaction can be provided for the decalcification softening reaction of subsequent circulating cooling sewageAnd (3) an alkali source.

A small amount of Na was added through a decalcifying reaction tank 208 via a line ⑦₂CO₃Controlling the pH value of the effluent to be 9.5-11, and blowing, aerating and stirring the effluent to dissolve Ca (HCO) in the circulating cooling sewage₃)₂、Mg(HCO₃)₂And NaOH, Ca (OH)2 and CaSO dissolved in the effluent of the calcium-adding reaction tank₄The following chemical reactions can occur:

Ca(HCO₃)₂+2NaOH→CaCO₃↓+Na₂CO₃+2H₂O

Mg(HCO₃)₂+2NaOH→MgCO₃↓+Na₂CO₃+2H₂O

Ca(OH)₂+Na₂CO₃→CaCO₃↓+2NaOH

CaSO₄+Na₂CO₃→CaCO₃↓+Na₂SO₄

it can be seen from this that: ca in water can be effectively removed through decalcification reaction²⁺、Mg²⁺Ions are used for softening the circulating cooling sewage with higher hardness; with simultaneous use of CaCO₃/MgCO₃The crystals further adsorb and remove organic colloid suspended matters in the water.

Further, blast aeration was performed on the calcium addition reaction tank 207 and the decalcification reaction tank 208: firstly, the reaction speed of calcium adding and decalcification is improved for enhancing stirring; the second is to oxidize the Mn/Fe divalent hydroxide which is slightly soluble in water under the alkaline condition to generate tri-valent and quadrivalent oxides which are insoluble in water and then precipitate and remove the oxides.

Through the flocculation reaction tank 209, a proper amount of sodium polyacrylate is added through the pipeline to promote the flocculation and increase of various calcium salts and iron/manganese oxide crystal particles adsorbing organic matters in the water so as to improve the sedimentation speed.

The water discharged from the flocculation reaction tank 209 is slowly raised at a speed of 0.2-0.5 m/h by the flocculation sedimentation tank 210, so that flocs such as calcium salt and the like are precipitated and separated, and the clear water overflowing from the sedimentation tank 210 enters the softened clear water tank 211 and is sent to the filtering and adsorbing process for further purification treatment by a pipeline ninthly.

The crystallized and flocculated sludge such as calcium salt extracted from the bottom of the sedimentation tank 210 is divided into two paths: one way is through the pipeline

Sequentially passes through the calcium adding reaction tank 207, the decalcification reaction tank 208 and the flocculation reaction tank 209, is used for adsorbing and removing colloidal organic matters in water, and finally flows back to the flocculation reaction tank 210; one way is through the pipeline

Sending the ammonia distillation wastewater into a calcium salt/carbon slurry adsorption tank 201 positioned in front of a COAOC biochemical system for adsorbing and removing emulsified tar in the ammonia distillation wastewater.

The Ca/COAOC/Ca process is characterized in that after a COAOC biochemical system, biochemical drainage and circulating cooling drainage are softened by calcium adding and decalcification reactions, and colloidal organic matters in the biochemical and circulating cooling drainage are adsorbed, flocculated and removed by utilizing calcium salt with large specific surface area and strong adsorption capacity, Mg/Fe/Mn hydroxide, oxide and other crystal particles generated by the softening reactions; meanwhile, before the COAOC biochemical system, the sludge is flocculated by using calcium salt, and the emulsified tar in the ammonia distillation wastewater is adsorbed and removed.

System ii is prepared by carbon slurry: feeding the small coke particles with the particle size of 3-5 mm into a wet ball mill 216 through a lifter 213, a coke storage tank 214 and a belt electronic scale 215 in sequence; simultaneously from the pipeline

Then, an appropriate amount of backwash wastewater from the filtration and adsorption step is extracted and sent to the wet ball mill 216. The carbon slurry flowing out of the ball mill passes through the carbon slurry intermediate tank 217 and the pipeline in sequence

Feeding into a carbon slurry classification tank 218; carbon slurry with the particle size of 0.05-0.1 mm and the water content of 50-60% overflows from the top of the carbon slurry grading tank 218 and is passed through a pipeline

Feeding into an aeration tank (O)205 of a COAOC biochemical system I; particle size>The 0.1 carbon slurry is discharged from the bottom of the carbon slurry classifying tank 218 and then returned to the wet ball mill 216.

Through a lime milk preparation system III, powdery CaO transported by a closed tank truck is fed into a CaO storage tank 219 through a pipeline ⑩ by means of compressed air, and a proper amount of the powdery CaO is fed into a lime milk preparation tank 221 through a screw feeder 220 and is simultaneously fed from the pipeline

The drawn-out backwash wastewater from the filtration and adsorption step is passed through the CaO dust trapping water jet 222 and then fed into the lime cream preparation tank 221. Furthermore, through the pipeline

And a water jet ejector 222 for recovering the CaO dust generated by charging the CaO storage tank to the lime milk preparation tank 221. The lime milk drawn from the lime milk preparation tank 221 is passed through a pipeline

Continuously fed into a calcium adding reaction tank 207 positioned after the COAOC biochemical system.

The technical characteristics of the steps are as follows: firstly, utilizing calcium salt flocculation sedimentation sludge and carbon slurry biochemical sludge to adsorb and remove emulsified tar in ammonia distillation wastewater; therefore, the water inlet COD of the biochemical system can be reduced, the water inlet B/C ratio of the biochemical system can be improved, and the water outlet COD of the biochemical system can be reduced. Secondly, the carbon slurry with the grain diameter of 0.05-O.1 is used as an adsorption and catalysis carrier of biochemical reaction organic matters and biochemical activated sludge to circulate in the OAO biochemical tank, and no nitrification liquid flows back between the anoxic tank (A) and the aeration tank (O). Thus, the concentration of active biochemical sludge in the OAO tank can be improvedThe degree and the biochemical reaction speed can prolong the retention biochemical reaction time of the wastewater in the AO pool. Thus, the COAOC process with A/O and A²Compared with the O process, the removal rate of the COD of the inlet water can be improved by about 10 percent, and the biochemical sludge bulking can be inhibited, thereby being beneficial to the sedimentation separation of the biochemical sludge. Thirdly, adding a proper amount of waste alkali from the filtering and adsorbing process into a pre-aeration tank (O) and an aeration tank (O) of a COAOC biochemical system, and controlling the pH value of the discharged water to be 7.5-8. Thus, not only can meet the alkali requirement of biochemical reaction, but also can make the organic matter in the waste alkali liquor be biochemically degraded, in particular, make the CO produced by biochemical degradation of organic matter₂Formation of NaHCO₃Dissolved in water to produce more CaCO during the calcium addition reaction₃And (4) adsorbing and removing organic colloid suspended matters in the biochemical wastewater by using the crystals. Fourthly, adding proper lime milk and sodium carbonate into biochemical and circulating cooling blowdown mixed wastewater in sequence, and controlling the pH value of effluent of the calcium adding and decalcification reaction tank to be 9-11; thus, the method aims to carry out softening treatment on biochemical and circulating cooling sewage mixed wastewater, and adsorb and remove colloidal organic matters in biochemical wastewater by utilizing Ca/Mg salt, Fe/Mn hydroxide and oxide crystal particles generated by softening reaction. Fifthly, the ascending speed of the clear liquid in the primary sedimentation tank, the calcium salt/biochemical slurry thickening barrel, the secondary sedimentation tank and the flocculation sedimentation tank is 0.2-0.5 m/h.

The technical characteristics make COD of the drainage water of the Ca/COAOC/Ca process lower than 20mg/L, the content of soluble substances is lower, the soluble substances mainly comprise sodium chloride and sodium hydroxide with high solubility, a small amount of sodium carbonate and sodium sulfate, and especially the Fe easy to precipitate and scale in the water²⁺、Ca²⁺、Mg²⁺、Mn²⁺/F^-、SiO₂The contents of divalent cations, fluoride ions and silicon dioxide are very low, and a foundation is laid for improving the fresh water yield and long-term stable operation in the subsequent reverse osmosis, electrodialysis and evaporation concentration processes.

The filtering and adsorbing unit 300 is constructed as shown in fig. 4, and includes: comprises a multi-medium filter 301, a microporous metal filter 302, an acidification reactor 303, a gas/liquid separation tank 304 and an activated carbon adsorption tank 305 which are connected in series in turn, and is provided with a dilute mixed acid tank 306, a dilute caustic soda tank 307, a circulating caustic soda tank 308, a spent caustic soda tank 309 and ultra-filtration sewageWater tank 310, microporous metal filtration concentrate and backwashing sewage tank 311, and

the process pipelines are connected.

The wastewater treatment step in the filtering and adsorbing unit 300 includes: the drained water from the Ca/COAOC/Ca unit 200 passes through a multi-media filter 301, a microporous metal filter 302, an acidification reactor 303, a gas/liquid separation tank 304 and an activated carbon adsorption tank 305 in sequence through a pipeline (i) and (ii).

Filtering and removing CaCO in water through a multi-medium filter 301 and a microporous metal filter 302 under the alkaline condition that the pH value of inlet water is 9.5-11₃、CaF₂、CaSiO₃、Mg(OH)₂、Fe(OH)₂、Mn(OH)₂、Fe₂O₃、MnO₂And the like, micro crystal particles and biochemical sludge residual suspended matters.

An appropriate amount of mixed acid (hydrochloric acid and a small amount of sulfuric acid) from the bipolar membrane electrodialysis process is added through a pipeline (c) in the acidification reactor 303, the pH value of effluent is controlled to be 4-5, and acid-base neutralization chemical reaction can occur.

CO generated in the acidification reaction process is separated and removed through a gas/liquid separation tank 304₂And (5) separating and removing.

Under the acidic condition with the pH value of 4-5, the acidic organic matters which are easy to dissolve in the alkaline water are converted from hydrophilic ionic states into hydrophobic molecular aggregation colloids and suspended matters through the activated carbon adsorption tank 305, so that the acidic organic matters can be adsorbed and removed through the activated carbon fixed bed. For the drainage of the activated carbon adsorption tank 305, the water is drained through a pipeline

Adding a proper amount of caustic soda, controlling the pH value to be 7-7.5, and sending the mixture to a reverse osmosis and electrodialysis unit 400 through a pipeline ⑤ for treatment.

At the same time, the concentrated ultrafiltration water from the reverse osmosis and electrodialysis unit 400 is piped

Sent to an ultrafiltration concentrated water tank 310 for reuse via a pipeline

Periodically back flushing the multimedia filter 301 through the pipeline

Periodically back-flushing the microporous metal filter 302 via a pipe

The residual alkali in the activated carbon adsorption tank 305 is periodically washed, and simultaneously the respective backflushed water passes through the pipeline respectively

Flows into a ceramic filtration and backwashing sewage tank 311; back washing the residual ultrafiltration concentrated water through a pipeline

Continuously fed into the fine pore metal filter 302 and is discharged from the sewage side of the filter 302 through the pipe

Continuously discharging, simultaneously taking out the micro particles intercepted by the ceramic filtration, then flowing into a micro-porous metal filtration concentrated water and backflushing sewage tank 311, and finally passing through a pipeline

The Ca/COAOC/Ca unit 200 is returned for use in the preparation of carbon slurry and milk of lime.

The activated carbon adsorbent bed in tank 305 is periodically washed and regenerated with hot alkali. Therefore, the ammonia evaporation wastewater from the ammonia evaporation and evaporation process with the temperature of 90-95 ℃ is required to be treated by a pipeline

Heating the alkali liquor to 80-85 ℃ through coil pipes in a waste alkali tank 309, a circulating alkali tank 308 and a dilute caustic soda tank 307 in sequence, and then evaporating ammonia wastewater through a pipeline

The sodium hydroxide with the concentration of about 15 to 20 percent from the bipolar membrane electrodialysis process is sent into a dilute sodium hydroxide groove 307 through a pipeline ⑧ and is sent into a circulating alkali groove 308 through a pipeline ⑨ periodically, and the circulating alkali liquor with the temperature of 85 ℃ in the circulating alkali groove 308 is reused and passes through a pipeline in turn

Activated carbon adsorption tank 305 and pipeline

The active carbon adsorption bed is washed periodically, meanwhile, the circularly washed waste alkali is sent into a waste alkali tank 309 through a pipeline ⑩, after alkali washing, the active carbon adsorption tank 305 is emptied, and the residual alkali in the active carbon adsorption bed is washed by ultrafiltration concentrated water.

The waste lye continuously drawn out from the waste lye tank 309 is recycled in three ways: the first path is sent into a composite ammonia still for ammonia distillation and evaporation processes and is used for decomposing fixed ammonium salt in the residual ammonia water; the second path and the third path are respectively sent into a preaeration tank and an aeration tank of the Ca/COAOC/Ca process, and are used for adjusting the pH value of the effluent of the two tanks to 7.5-8, biochemically degrading organic matters in the waste alkali and simultaneously generating CO generated by biochemically degrading the organic matters₂Formation of NaHCO₃Dissolving in water.

In summary, the technical features of this step are: firstly, under the alkaline condition that the pH value of inlet water is 9.5-11, a multi-medium filtration and micropore metal filtration combined method is adopted to filter and remove calcium salt, iron/manganese/magnesium hydroxide, oxide and other crystal particles and biochemical sludge residual suspended matters in the effluent of the biochemical and softening process. And secondly, under the acidic condition that the pH value of the inlet water is 4-5, an active carbon fixed bed is adopted to adsorb and remove organic matters in the effluent of the biochemical and softening procedures. Thirdly, the sensible heat of the ammonia distillation wastewater is firstly utilized to heat the alkali liquor, and then the hot alkali liquor is utilized to periodically wash and regenerate the activated carbon adsorption fixed bed. Fourthly, the waste alkali discharged by the washing and regeneration of the activated carbon adsorption tank is reused in the biochemical treatment process of the residual ammonia water ammonia evaporation decomposition fixed ammonium salt and the ammonia evaporation wastewater, and finally, organic matters in the waste alkali are biochemically degraded. Fifthly, the ultrafiltration concentrated water is continuously fed into the microporous metal filter and continuously extracted from the sewage side of the microporous metal filter, so that particle suspended matters intercepted by the microporous metal are continuously carried out.

Through the steps of filtering and adsorbing, the suspended matter and organic matter in the water can be effectively removed, the COD of the discharged water is less than 15mg/L, and the dissolved salt mainly comprises sodium chloride with high solubility and a small amount of sodium sulfate, especially Fe²⁺、Ca²⁺、Mg²⁺、Mn²⁺/F^-、SiO₂The contents of divalent cations, fluoride ions and silicon dioxide are very low, which is beneficial to the long-term stable operation of the reverse osmosis and electrodialysis processes and the improvement of the fresh water yield.

The reverse osmosis and electrodialysis unit 400 is shown in fig. 5 and comprises: an ultrafiltration water inlet tank 401, an ultrafiltration pressure pump 402, an ultrafiltration cartridge filter 403, an ultrafiltration membrane component 404, a reverse osmosis water inlet tank 405, a reverse osmosis pressure pump 406, a reverse osmosis cartridge filter 407, a reverse osmosis membrane component 408 and a reverse osmosis fresh water tank 409 are sequentially connected in series, and an ion exchange resin tower 410, a primary EDR electrodialysis component 411, a primary EDR concentrated water tank 412, a secondary EDR feed pump 413, a secondary EDR component 414, a secondary EDR concentrated water tank 415, a secondary EDR concentrated water pump 416, an activated carbon adsorber 417 and a concentrated water intermediate tank 418 are sequentially connected in series and are sequentially connected with an electrodialysis water inlet tank 401, an ultrafiltration pressure pump 402, an ultrafiltration cartridge

Wherein, the process pipeline is connected with the pipeline ⑩

And fresh water outlets of the first-stage EDR electrodialysis assembly 11 and the second-stage EDR electrodialysis assembly 13 are communicated with the reverse osmosis water inlet pool 5.

The treatment steps of the reverse osmosis and electrodialysis unit 400 include: the drained water from the filtering and adsorbing unit 300 with the pH value of 7-7.5 flows into an ultrafiltration water inlet tank 401 through a pipeline I, and a proper amount of bactericide and reducing agent are respectively added into a water inlet and a water outlet of the tank, are pumped out by an ultrafiltration pressure pump 402 and sequentially pass through an ultrafiltration cartridge filter 403 and an ultrafiltration membrane module 404.

The concentrated water discharged from the ultrafiltration module 404 is sent to the filtration and adsorption process by means of the pipeline (v). The clear water discharged from the ultrafiltration membrane module 404 is mixed with the fresh water from the electrodialysis module, flows into the reverse osmosis water inlet tank 405 through the pipeline r, is pumped out by the reverse osmosis booster pump 406, sequentially passes through the cartridge filter 407 and the reverse osmosis membrane module 408, and controls the pH value of the reverse osmosis inlet water to be 7 by adjusting the pH value of the electrodialysis fresh water.

For the concentrated brine discharged from the reverse osmosis membrane module 408, firstly adding a proper amount of dilute alkali from the bipolar membrane electrodialysis process, adjusting the pH value to 8-8.5, and then sending the concentrated brine into the ion exchange resin tower 410 through a pipeline ⑦ by means of self excess pressure to remove Fe in the reverse osmosis concentrated brine²⁺、Ca²⁺、Mg²⁺And Mn²⁺And divalent cations. For this purpose, the ion exchange resin column 410 is periodically washed and regenerated by using a dilute alkali and a mixed acid from the bipolar membrane electrodialysis.

The brine discharged from the ion exchange resin column 410 and deprived of divalent cations is sent to the electrodialysis primary EDR module 411 through the pipeline ⑨, and the strong brine discharged from the electrodialysis primary EDR module 411 is sent to the ion exchange resin column through the pipeline

Flows into a first DER concentrated water tank 412 and is divided into two paths by a second electrodialysis feeding pump 413: one way is through the pipeline

Flows back to the primary EDR module 411, and the other path passes through a pipeline

Sent to a secondary electrodialysis EDR module 414.

Fresh water produced by the electrodialysis primary EDR module 412 and the electrodialysis secondary EDR module 414 is respectively led to the pipeline ⑩ and the pipeline

Flows into a reverse osmosis water inlet tank 405, is pumped out by a reverse osmosis booster pump 406, sequentially passes through a cartridge filter 407 and a reverse osmosis membrane component 408, and continues desalination and desalination. And adding appropriate amount of mixture at the inlet of

electrodialysis modules

412 and 414 respectivelyThe pH value of reverse osmosis inlet water is controlled to be 7 by adjusting the pH value of electrodialysis fresh water by acid (hydrochloric acid + sulfuric acid). the desalted fresh water produced by the reverse osmosis membrane module 408 flows into a reverse osmosis fresh water tank 409 through a pipeline ⑥ and is sent out for a boiler water supply system and a coking production circulating cooling water system through a pipeline ⑧.

Concentrated water with salt content of 3-4% discharged from the secondary electrodialysis EDR component 414 is discharged through a pipeline

Flows into a secondary EDR concentrated water tank 415, is pumped by a pump 416 and is divided into two paths: one way is through the pipeline

Flow back to the secondary EDR assembly 414; the other path is through the pipeline

Adding a proper amount of mixed acid, controlling the pH value to be 4-5, feeding the mixture into an activated carbon adsorber 417, further adsorbing and removing organic matters in the brine, and then passing through a pipeline

Adding a proper amount of dilute alkali, controlling the pH value to be 8-8.5, flowing into a concentrated brine intermediate tank 418, and then passing through a pipeline

Sending to ammonia evaporation and evaporation processes for further evaporation and concentration, and finally producing dilute alkali and mixed acid through a bipolar membrane electrodialysis process. In addition, to use the dilute alkali produced by the bipolar membrane electrodialysis unit 500, the activated carbon adsorption bed in the adsorption tank 417 is periodically washed and regenerated, and the washing waste alkali is passed through the pipeline

And (5) sending the waste alkali into a waste alkali tank in the filtering and adsorbing process for recycling.

In summary, the technical features of this step are: firstly, filtering the purified water from the step 3 of the process by an ultrafiltration membrane component under the condition that the pH value is 7-7.5, adding a proper amount of acid to control the pH value to be 6.5-7, and performing light/thick separation by a reverse osmosis membrane component. And secondly, returning the ultrafiltration concentrated water to the step 3 of the working procedure for backwashing the filtration and adsorption components. Thirdly, adding a proper amount of caustic soda into reverse osmosis concentrated water to control the pH value of the reverse osmosis concentrated water to be 8-8.5, removing divalent cations in the water through ion exchange, further performing light/concentration separation through a two-stage series electrodialysis EDR assembly, and refluxing fresh water discharged by the two-stage electrodialysis assembly to the reverse osmosis membrane assembly for continuous desalination and desalination; therefore, the yield of the fresh water in the working procedure is as high as 93.5%, the discharge amount of the concentrated brine is only 6.5% (the salt content is about 3-4%), and the subsequent evaporation concentration load and energy consumption can be obviously reduced. Fourthly, adding a proper amount of acid into an inlet of the electrodialysis assembly, and controlling the pH value of electrodialysis concentrated water to be 6.5; in this way, it is intended to prevent the divalent cations from forming salts or hydroxide precipitates so as not to clog the electrodialysis membrane and increase the electrode resistance. Fifthly, adding a proper amount of acid into the electrodialysis discharged concentrated brine to control the pH value of the electrodialysis discharged concentrated brine to be 4-5, removing organic matters in the brine through activated carbon adsorption, and adding a proper amount of caustic soda to control the pH value to be 8-8.5 so as to inhibit corrosion of anions such as chloride ions, sulfate radicals and the like to subsequent evaporation and concentration equipment.

The bipolar membrane electrodialysis unit 500 is shown in FIG. 6, and comprises a settling tank 501, a brine clear solution tank 502, a cellulose-coated filter 503 for α, an ion exchange resin tower 504, a Bipolar Membrane Electrodialysis (BMED) module 505, and a brine circulation tank 506 which are connected in series in sequence, and further comprises a mixed acid product tank 507, a dilute alkali product tank 508, a sludge and resin regeneration sewage tank 509, and a pipeline

And connecting to form the product.

The step of abolishing the treatment in the bipolar membrane electrodialysis unit 500 comprises: adding a proper amount of alkali into concentrated brine which is from ammonia evaporation and evaporation processes and contains 15-20% of salt through two-stage evaporation concentration, adjusting the pH value of the concentrated brine to 9-10, and sending the concentrated brine into a Dalton settling barrel 501 through a pipeline to separate and remove hydroxides of metals such as iron, manganese, calcium, magnesium and the like in the brine.

The saline clear liquid overflowing from the top of the dalton settling barrel 501 flows into a saline clear liquid tank 502 through a pipeline, is sent into an alpha cellulose coating filter 503 through a pipeline, is sent into an ion exchange resin tower 504 through a pipeline, is added with proper self-produced mixed acid to control the pH value to be 6-6.5 through a pipeline, and is sent into a bipolar membrane electrodialysis assembly 505 for producing dilute alkali and mixed acid.

The mixed acid produced by the bipolar membrane electrodialysis assembly 505 is mixed acid of hydrochloric acid and sulfuric acid, flows into the mixed acid product tank 507 through a pipeline ⑨, is sent to filtration and adsorption, reverse osmosis and EDR electrodialysis and acid points used in various parts of the process through a pipeline ⑩, is mainly used for acid washing regeneration of ion exchange resin and pH adjustment of process water, and the rest is carried out through a pipeline

And (4) an outer pin.

Dilute alkali produced by the bipolar membrane electrodialysis component 505 is led out by a pipeline

Flows into a dilute alkali product tank 508 and then is piped

The water is sent to filtration and adsorption, reverse osmosis and EDR electrodialysis and alkali points at all parts of the process, and all the alkali points are used for meeting the requirements of activated carbon adsorption bed washing regeneration, ion exchange resin bed washing regeneration and water treatment process PH regulation. The waste alkali is washed and regenerated by using an activated carbon adsorption bed, and the alkali requirement in the processes of ammonia distillation of residual ammonia water and biochemical treatment of ammonia distillation wastewater is met.

The saline discharged by the bipolar membrane electrodialysis assembly 505 flows into the saline circulation tank 506 through a pipeline and then flows back to the bipolar membrane electrodialysis assembly 505 through a pipeline; meanwhile, a small amount of bipolar membrane electrodialysis residual liquid is sent to the ammonia evaporation and evaporation working procedure through a pipeline to be further evaporated and concentrated.

The mud discharged from the bottom of the dalbergia barrel 501 is discharged through a pipeline

Sending into a sludge settling and resin regeneration sewage tank 509, and washing the regeneration wastewater with acid and alkali from the ion exchange resin tower 504 of the procedure and the ion exchange resin tower of the reverse osmosis and EDR electrodialysis procedures respectively through pipelines

And a pipe

And into a tank 509. Finally, the sludge and the sewage in the tank 509 are led through the pipeline

Sending the mixture to a coking plant for dedusting, ash discharging and humidifying.

The technology of the steps is characterized in that firstly, the salt-containing wastewater is subjected to coking evaporation concentration and sequentially passes through a Dalton settling barrel, an α cellulose coating filter and an ion exchange resin tower under the alkaline condition that the pH value is 9-10 so as to remove Ca in the salt water²⁺、Mg²⁺、Fe²⁺And Mn²⁺And divalent cations. Secondly, the coking evaporation concentration salt-containing wastewater is adopted to produce caustic soda and hydrochloric acid by adopting a bipolar membrane electrodialysis method, so that the coking salt-containing wastewater is recycled.

It will be understood by those skilled in the art that the apparatus and method of the present invention are not limited to the embodiments described in the detailed description, and the detailed description is for the purpose of explanation and not limitation. Other embodiments will be apparent to those skilled in the art from the following detailed description, which is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Claims

1. An apparatus for treating coking wastewater, the apparatus comprising: an ammonia evaporation and evaporation unit, a Ca/COAOC/Ca treatment unit, a filtration and adsorption unit, a reverse osmosis and electrodialysis unit and a bipolar membrane electrodialysis unit.

2. The apparatus of claim 1, wherein the ammonia distillation and evaporation unit comprises: a coarse grained oil/water separation tank, a composite ammonia still, a heavy tar catcher, an ammonia still wastewater heat exchanger, an ammonia still wastewater cooler, a brine positive pressure evaporation unit and a brine negative pressure evaporation unit.

3. The apparatus of claim 2, wherein the coarse oil/water separation tank comprises: an oil storage chamber, a coarse granulation chamber, a settling chamber, a circulation chamber and a clear liquid chamber; the bottom of the oil storage chamber is provided with a tar discharge port, the inside of the coarse granulation chamber is provided with mesh corrugated packing and a residual ammonia water feeding distributor from top to bottom, the distributor is connected with an oil-containing residual ammonia water inlet, the heavy tar inlet is connected with the lower part of the coarse granulation chamber, the inside of the sedimentation chamber is provided with a corrugated plate packing layer, the upper part of the sedimentation chamber is provided with an annular sawtooth overflow weir, the clear solution chamber is provided with a liquid level meter connector, a clear solution chamber diffusion pipe and a deoiling residual ammonia water clear solution outlet, and is provided with a circulating flow chamber and clear solution chamber communicating pipe and a settling chamber and.

4. The apparatus of claim 2, wherein the composite ammonia still comprises a lower section, a middle section, and an upper section; the lower section is internally provided with a horn-shaped downcomer and a mesh corrugated collecting layer from bottom to top, and is also provided with an ammonia distillation wastewater outlet, a liquid level meter interface and a steam inlet, the middle section is provided with a plurality of layer plate type mass transfer tower trays, the top layer mass transfer tower tray is provided with a fractionating liquid inlet and an alkali liquid inlet, the upper section is internally provided with a pall ring packing layer, the bottom of the packing layer is provided with a hump support, the top of the packing layer is provided with a feeding distributor, the distributor is connected with a residual ammonia water feeding port, the top of the upper section is provided with an ammonia distillation steam outlet, the lower section and the middle section are provided with a liquid phase collecting broken tower tray, the broken tower tray is provided with a fractionating liquid outlet.

5. The apparatus of claim 2, wherein the heavy tar trap comprises: a tar collecting chamber, a settling and trapping chamber and a clear liquid chamber; the bottom of the tar collecting chamber is provided with a tar discharging port, the settling and trapping chamber is internally provided with a mesh corrugated trapping layer, a trumpet down-flow pipe and a down-flow pipe fixing rib plate from top to bottom, the trumpet down-flow pipe is connected with a fractional liquid inlet, a clear liquid distribution umbrella cap is arranged in the clear liquid chamber, and the top of the clear liquid chamber is provided with a fractional clear liquid outlet.

6. The apparatus of claim 2, wherein the brine positive pressure evaporator unit comprises: the system comprises a brine preheater, a positive pressure evaporator, a positive pressure evaporation heater, a steam condensate water tank, a positive pressure evaporation mother liquor circulating pump and a condensate water conveying pump which are connected by a process pipeline.

7. The apparatus of claim 2, wherein the brine negative pressure evaporation unit comprises: the system comprises a negative pressure evaporation heater, an ammonia condensate cooler, a dilute ammonia water tank, a negative pressure evaporator, an evaporation steam condenser, an evaporation condensate water high-level tank, a negative pressure evaporation mother liquor circulating pump and a vacuum pump which are connected by a process pipeline.

8. The apparatus of claim 1, wherein the Ca/COAOC/Ca processing unit comprises: the system comprises a calcium salt/carbon slurry adsorption tank, a primary sedimentation tank, a COAOC biochemical system I, a calcium adding reaction tank, a decalcification reaction tank, a flocculation sedimentation tank and a softened clean water tank which are connected in series in sequence by a process pipeline, and is provided with a calcium salt/carbon slurry/biochemical sludge thickening barrel, a carbon slurry preparation system II, a lime milk preparation system III and an ammonia distillation wastewater/circulating cooling sewage heat exchanger.

9. The apparatus according to claim 8, wherein the COAOC system i comprises a pre-aeration tank (O), an anoxic tank (a), an aeration tank (O) and a secondary sedimentation tank of a carbon slurry cycle connected in series in this order.

10. The apparatus of claim 8, wherein the carbon slurry preparation system II comprises: a small coke particle hoister, a small coke particle storage tank, a belt scale electronic, a wet ball mill, a carbon slurry intermediate tank and a carbon slurry grading tank which are connected by a process pipeline.

11. The apparatus of claim 8, wherein the milk of lime preparation system III comprises: a CaO storage tank, a CaO adjusting screw feeder, a lime milk preparation tank and a CaO dust collecting water flow ejector which are connected by a process pipeline.

12. The apparatus of claim 1, wherein the filtration and adsorption unit comprises: the multi-medium filter, the microporous metal filter, the acidification reactor, the gas/liquid separation tank and the activated carbon adsorption tank which are connected by a process pipeline are sequentially connected in series, and the device comprises a dilute mixed acid tank, a dilute caustic soda tank, a circulating alkali tank, a waste alkali tank, an ultrafiltration sewage tank and a ceramic filtration and back flushing sewage tank.

13. The apparatus of claim 1, wherein the reverse osmosis and electrodialysis unit comprises: the system comprises an ultrafiltration water inlet tank, an ultrafiltration pressure pump, an ultrafiltration cartridge filter, an ultrafiltration membrane component, a reverse osmosis water inlet tank, a reverse osmosis pressure pump, a reverse osmosis cartridge filter, a reverse osmosis membrane component and a reverse osmosis fresh water tank which are sequentially connected in series, and an ion exchange resin tower, a first-stage EDR electrodialysis component, a first-stage EDR concentrated water tank, a second-stage EDR feed pump, a second-stage EDR electrodialysis component, a second-stage EDR concentrated water tank, a second-stage EDR concentrated water pump, an activated carbon adsorber and a strong brine intermediate tank which are sequentially connected in; and the fresh water outlet of the first-stage EDR electrodialysis assembly and the fresh water outlet of the second-stage EDR electrodialysis assembly are communicated with the reverse osmosis water inlet pool through a process pipeline.

14. The device of claim 1, wherein the bipolar membrane electrodialysis unit comprises: the device comprises a settling barrel, a saline water clear solution tank, an alpha cellulose coating filter, an ion exchange resin tower, a Bipolar Membrane Electrodialysis (BMED) component and a saline water circulating tank which are connected in series in sequence, wherein the settling barrel, the saline water clear solution tank, the alpha cellulose coating filter, the ion exchange resin tower, the BMED component and the saline water circulating tank are connected in series in sequence, and the settling barrel, the saline water clear solution tank, the BMED component and the.

15. A method for treating coking wastewater using the apparatus for treating coking wastewater according to any one of claims 1 to 14, characterized by comprising the steps of:

(1) deoiling and distilling the residual coking ammonia water through a granular oil/water separation tank, a composite ammonia still and a heavy tar catcher respectively to obtain ammonia distillation wastewater;

(2) cooling part of the ammonia distillation wastewater by an ammonia distillation wastewater heat exchanger and an ammonia distillation wastewater cooler, and sequentially performing adsorption and deoiling, COAOC biochemical processes, calcium adding reaction, decalcification reaction, flocculation reaction and flocculation precipitation by a Ca/COAOC/Ca unit to obtain softened water;

(3) filtering the softened water obtained in the step (2) by a filtering and adsorbing unit sequentially through multi-medium filtering, microporous metal filtering, acidification reaction, gas/liquid separation and activated carbon adsorption purification to obtain filtered, adsorbed and purified water; adsorbing and draining water by using activated carbon, and adding a proper amount of alkali to control the pH value to be 7-7.5;

(4) and (3) carrying out ultrafiltration and reverse osmosis light/concentration separation on the filtered and adsorbed purified water obtained in the step (3), adding a proper amount of caustic soda into reverse osmosis concentrated water to control the pH value to be 7.5-8, removing divalent cations such as calcium/magnesium/iron/manganese in the water through ion exchange resin, and carrying out electrodialysis light/concentration separation.

16. The method according to claim 15, wherein the deoiling in step (1) specifically comprises: the coking residual ammonia water is sequentially subjected to coarse graining sedimentation and trapping, steam stripping and fractionation at the upper section of a compound ammonia still and gravity sedimentation and trapping, steam stripping and fractionation at the middle section of the compound ammonia still and gravity sedimentation and trapping and deoiling at the lower section of the compound ammonia still, heavy tar in the residual ammonia water is removed through three times of sedimentation and trapping, and light tar in the residual ammonia water is removed through two times of steam stripping and fractionation.

17. The method according to claim 15, wherein the ammonia distillation in step (1) comprises: the brine evaporation steam discharged by the brine positive pressure evaporation unit is used as a heat source, and the residual ammonia water is subjected to twice steam stripping and ammonia distillation through the upper section and the middle section of the composite ammonia distillation tower.

18. The method of claim 15, wherein the adsorptive deoiling in step (2) comprises: calcium salt sludge produced by flocculation precipitation and carbon slurry biochemical sludge produced in the COAOC process are utilized to adsorb and remove emulsified tar in ammonia distillation wastewater.

19. The method of claim 15, wherein the COAOC biochemical process in step (2) comprises: and (2) making small-particle coke with the particle size of 3-5 mm into carbon slurry with the particle size of 0.05-0.1 mm and the water content of 40-60% by using a carbon slurry preparation system II through a wet grinding machine, adding the carbon slurry into an aeration tank (O) of a COAOC system as an activated biochemical sludge and organic matter biochemical degradation adsorption catalysis carrier, and circulating the carbon slurry among a pre-aeration tank (O), an anoxic tank (A), the aeration tank (O) and a secondary sedimentation tank of the COAOC system.

20. The method of claim 15, wherein the method in step (3) further comprises activated carbon adsorption bed scrubbing regeneration: and (2) cooling the rest part of the ammonia evaporation wastewater in the step (1) to 90-95 ℃ through an ammonia evaporation wastewater heat exchanger, heating the caustic soda water solution with the sodium hydroxide content of 15-20% to 80-85 ℃, and washing and regenerating the activated carbon adsorption bed by using hot alkali liquor.

21. The method of claim 15, wherein step (1) further comprises: and (4) adding mixed acid (hydrochloric acid and sulfuric acid) into the concentrated brine separated by the electrodialysis in the step (4), controlling the pH value to be 4-5, adsorbing and purifying by using activated carbon, adding caustic soda, controlling the pH value to be 8-8.5, and performing evaporation concentration by using a brine positive pressure evaporation unit and a brine negative pressure evaporation unit to obtain evaporation concentration brine.

22. The process according to claim 15, characterized in that it further comprises a step (5) of producing caustic soda and mixed acids (hydrochloric acid + sulfuric acid) by means of a bipolar membrane electrodialysis unit, in particular comprising: adding caustic soda into the evaporated and concentrated brine, and controlling the pH value to be 9-10; sequentially passing through a dalton settling barrel, an alpha cellulose coating filter and an ion exchange resin tower to remove suspended matters and divalent cations such as calcium, magnesium, iron, manganese and the like in the brine; and adding mixed acid, controlling the pH value of the concentrated brine to be 6.5-7, and producing caustic soda and mixed acid (hydrochloric acid and sulfuric acid) through a bipolar membrane electrodialysis assembly.

23. The method according to claim 21, wherein the step (1) of subjecting the electrodialysis concentrated water to two-stage evaporation concentration by a brine positive pressure evaporator unit and a brine negative pressure evaporator unit to obtain the concentrated brine specifically comprises: carrying out primary evaporation concentration on the electrodialysis concentrated water by using primary steam as a heat source through a saline water positive pressure evaporation unit; and (3) taking the oily ammonia-containing steam escaping from the top of the composite ammonia still as a heat source, and continuously evaporating and concentrating the first-stage evaporated strong brine through a brine negative pressure evaporation unit to obtain the strong brine.