CN117800462A - Method for recycling sewage discharged by blast furnace gas washing circulating water - Google Patents
Method for recycling sewage discharged by blast furnace gas washing circulating water Download PDFInfo
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- CN117800462A CN117800462A CN202311831906.3A CN202311831906A CN117800462A CN 117800462 A CN117800462 A CN 117800462A CN 202311831906 A CN202311831906 A CN 202311831906A CN 117800462 A CN117800462 A CN 117800462A
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 112
- 239000010865 sewage Substances 0.000 title claims abstract description 59
- 238000005406 washing Methods 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000004064 recycling Methods 0.000 title claims abstract description 33
- 238000001914 filtration Methods 0.000 claims abstract description 42
- 238000004140 cleaning Methods 0.000 claims abstract description 28
- 238000001556 precipitation Methods 0.000 claims abstract description 24
- 238000005345 coagulation Methods 0.000 claims abstract description 21
- 230000015271 coagulation Effects 0.000 claims abstract description 21
- 238000005189 flocculation Methods 0.000 claims abstract description 20
- 230000016615 flocculation Effects 0.000 claims abstract description 20
- 239000002351 wastewater Substances 0.000 claims abstract description 14
- 230000008569 process Effects 0.000 claims abstract description 10
- 239000007789 gas Substances 0.000 claims description 39
- 239000010802 sludge Substances 0.000 claims description 23
- 239000004744 fabric Substances 0.000 claims description 21
- 238000004062 sedimentation Methods 0.000 claims description 15
- 239000000701 coagulant Substances 0.000 claims description 12
- 239000000945 filler Substances 0.000 claims description 12
- 239000000706 filtrate Substances 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 9
- 239000006004 Quartz sand Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims description 6
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 claims description 6
- 239000000428 dust Substances 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- JMANVNJQNLATNU-UHFFFAOYSA-N oxalonitrile Chemical compound N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 claims description 6
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 claims description 4
- 239000003830 anthracite Substances 0.000 claims description 4
- 239000002223 garnet Substances 0.000 claims description 4
- 229920002401 polyacrylamide Polymers 0.000 claims description 4
- 238000011085 pressure filtration Methods 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 3
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 239000011701 zinc Substances 0.000 claims description 3
- 229910052725 zinc Inorganic materials 0.000 claims description 3
- 238000004065 wastewater treatment Methods 0.000 abstract description 4
- 238000012423 maintenance Methods 0.000 abstract description 2
- 230000008439 repair process Effects 0.000 abstract description 2
- 230000009466 transformation Effects 0.000 abstract 1
- 239000007788 liquid Substances 0.000 description 9
- 238000011010 flushing procedure Methods 0.000 description 8
- 230000007613 environmental effect Effects 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 229940037003 alum Drugs 0.000 description 2
- -1 and after treatment Inorganic materials 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000003034 coal gas Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 230000020477 pH reduction Effects 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003311 flocculating effect Effects 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/18—Nature of the water, waste water, sewage or sludge to be treated from the purification of gaseous effluents
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
The invention discloses a recycling method of blast furnace gas washing circulating water sewage, which comprises the steps of firstly carrying out flocculation precipitation treatment and filtration treatment on the blast furnace gas washing circulating water sewage to obtain clean water with the water temperature not exceeding 40 ℃, and then cleaning a filter press; the flocculation precipitation treatment comprises primary coagulation treatment, secondary fine coagulation treatment and rapid precipitation treatment which are sequentially carried out; the filtering treatment comprises a primary filtering treatment and a secondary filtering treatment which are sequentially carried out. The method realizes the resource utilization of the wastewater by recycling the treated blast furnace gas washing circulating water sewage; the new water consumption and the running cost of the filter press are reduced, and the conventional equipment is adopted, so that the process flow is simple, the maintenance and the repair are convenient, the application range is wide, and the on-site transformation is easy; the sewage regenerated in the recycling process is returned to the flocculation precipitation step for recycling, so that the wastewater discharge is reduced and the wastewater treatment cost is reduced through the internal recycling.
Description
Technical Field
The invention relates to the field of industrial wastewater treatment, in particular to a recycling method for sewage discharged by circulating water of blast furnace gas washing.
Background
The blast furnace gas washing water is waste water generated by wet dust removal of the blast furnace. Wet dedusting is to dedust blast furnace gas by using a gravity deduster and a double venturi system or a gravity deduster and a Bischiff system. The coal gas from the blast furnace is first removed with the gravitational dust collector to eliminate large dust and then introduced into the coal gas washing system via pipeline for cleaning and cooling. The sewage generated after the cleaning and cooling are circulated for a plurality of times is the blast furnace gas washing wastewater, namely the blast furnace gas washing circulating water sewage. The water temperature of the wastewater is up to above 60 ℃, and the wastewater contains a large amount of suspended matters consisting of iron ore powder and coke powder, phenol, cyanogen, ammonia nitrogen, sulfide, zinc and the like. The wastewater has large water volume and heavy pollution, and must be treated and then recycled as much as possible.
Filter presses are used for the separation of solids and liquids. The basic principle of solid-liquid separation is as follows: the mixed liquid flows through the filter medium, namely the filter cloth, and the solids stay on the filter cloth and are gradually accumulated on the filter cloth to form a filter mud cake. And the filtrate part permeates the filter cloth to become clear liquid without solid. The filtrate passes through the filter cloth and flows to the corner channels of the plate frame along the grooves of the filter plate, and is discharged in a concentrated way. After the filtration is finished, washing water can be introduced to wash filter residues. After washing, compressed air is sometimes introduced to remove the remaining washing liquid. And then opening the filter press to remove filter residues, cleaning filter cloth, re-compacting the plates and frames, and starting the next working cycle. The waste liquid generated by cleaning the filter cloth of the filter press needs to be collected and treated intensively. And in the operation process of the filter press, the filter cloth adhered with filter residues is washed by using new water, so that the filter cloth is repeatedly used, the continuous new water washing causes the large increase of the wastewater production amount, the load of a water treatment system is increased, the large environmental protection pressure is brought, and the operation cost of the filter press is high due to the large consumption of the new water. Therefore, how to reduce the new water consumption of the filter press and the load of the water treatment system is a problem to be solved urgently.
Based on the requirements of environmental protection and cost control, the sewage discharged by the blast furnace gas washing circulating water must be treated and recycled as much as possible. And the new water consumption for flushing the filter press is high, so that the problem of high cost is also needed to be solved. Based on the above, the inventor considers and researches a new technical scheme, and the sewage discharged from the blast furnace gas washing circulating water is recycled to the filter press for cleaning, so that the aims of environmental protection, energy saving and cost reduction are realized.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a recycling utilization method of the blast furnace gas washing circulating water sewage, which can realize recycling utilization and recycling of the blast furnace gas washing circulating water sewage, and on the other hand, the new water consumption of a filter press is reduced, the running cost of the filter press is reduced, and the purposes of energy conservation and environmental protection are achieved.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a method for recycling the sewage of the washing circulating water of blast furnace gas includes such steps as flocculating settling treatment and filtering to obtain clean water with water temp not higher than 40 deg.C, and washing filter press; the blast furnace gas washing circulating water sewage is waste water which is generated by blast furnace wet dust collection and contains a large amount of iron ore powder, coke powder suspended matters, phenol, cyanogen, ammonia nitrogen, sulfide, zinc and other components.
Preferably, the flocculation precipitation treatment comprises a primary coagulation treatment, a secondary fine coagulation treatment and a rapid precipitation treatment which are sequentially performed.
Preferably, the primary coagulation treatment comprises adding Ca (OH) into the blast furnace gas washing circulating water sewage 2 Controlling the pH value of the sewage discharged by the blast furnace gas washing circulating water to be not more than 9, stirring for 10-15min at the rotating speed of 180-220r/min, and standing for not less than 15min to obtain the sewage after primary coagulation treatment.
Preferably, the secondary fine coagulation treatment comprises the following steps: adding coagulant and coagulant aid into the sewage after primary coagulation treatment, stirring for 8-10min at the rotating speed of less than or equal to 100r/min so as to enable the added coagulant aid and coagulant aid to be rapidly dispersed, and fully and uniformly mixing with the sewage; standing for at least 15min to form small flocs in the sewage; the coagulant comprises polyaluminum chloride and/or aluminum sulfate, and the coagulant aid comprises polyacrylamide.
Preferably, the rapid sedimentation treatment is to drain the sewage after the secondary fine coagulation treatment to the bottom of a flow guide pipe in a reaction tank, stir and mix the sewage from bottom to top, and then react in a form of slow stirring and plug flow so as to form large flocs in the sewage, thereby realizing rapid sedimentation.
Preferably, sludge dewatering treatment is carried out on the sludge obtained after the flocculation precipitation treatment is finished; the sludge dewatering treatment comprises the step of carrying out pressure filtration on sludge by using the pressure filter, and returning the sewage after pressure filtration to the flocculation precipitation treatment step for recycling.
Preferably, the filtering treatment comprises a first-stage filtering treatment and a second-stage filtering treatment which are sequentially carried out, wherein the first-stage filtering treatment adopts a multi-medium filter to filter the effluent after the flocculation and precipitation treatment is finished, and the second-stage filtering treatment adopts a filter with the filtering precision of 0.1mm and the mesh of a filter screen of 120 meshes to filter the effluent after the first-stage filtering treatment; wherein, the multi-medium filter adopts a two-stage sub-filtering mode, the filler adopted by the first-stage sub-filtering is anthracite and quartz sand, and the filler adopted by the second-stage sub-filtering is garnet and quartz sand.
Preferably, the quality indexes of the clean water obtained after the flocculation precipitation treatment and the filtration treatment comprise: the pH value is 7-8, SS is less than or equal to 20mg/L, ca is less than 200mg/L, and the total hardness is CaCO 3 The total concentration is less than 300mg/L, cl is less than 120mg/L, COD is less than or equal to 20mg/L, and ammonia nitrogen is less than or equal to 180mg/L.
Preferably, the filter press comprises a plate and frame filter press or a belt filter press; the clean water obtained after the flocculation precipitation treatment and the filtration treatment is used for cleaning filter cloth, filter plate surfaces, filtrate discharge holes and filtrate channels of a plate-and-frame filter press or filter belts and mesh bags of a belt filter press.
Preferably, effluent water after the sludge dewatering treatment of the filter press and sewage generated in the cleaning process of the filter press are returned to the flocculation precipitation treatment step for recycling.
Compared with the prior art, the invention has the beneficial effects that:
(1) The method realizes the resource utilization of the wastewater by recycling the treated blast furnace gas washing circulating water sewage.
(2) The method reduces the new water consumption and the running cost of the filter press, and has the advantages of simple process flow, convenient maintenance and repair, wide application range and easy field reconstruction by adopting conventional equipment.
(3) The method returns the sewage regenerated in the recycling process of the blast furnace gas washing circulating water sewage to the flocculation precipitation step for recycling, reduces the wastewater discharge through the internal recycling, and reduces the wastewater treatment cost.
In summary, the method of the invention can recycle the treated blast furnace gas washing circulating water, thereby realizing the recycling of the wastewater on one hand, and reducing the process water cost and the wastewater treatment cost on the other hand, so as to achieve the purposes of energy conservation and environmental protection.
Detailed Description
For a better explanation of the present invention, the main content of the present invention is further elucidated below in conjunction with the specific examples, but the content of the present invention is not limited to the following examples only.
Example 1
The embodiment utilizes the blast furnace gas washing circulating water sewage resource by the blast furnace gas washing circulating water sewage resource utilization method designed by the invention.
The sewage discharged by the blast furnace gas washing circulating water is recycled after the wastewater generated by the blast furnace wet dust removal is subjected to coagulating sedimentation and cooling treatment.
The method for recycling the sewage of the blast furnace gas washing circulating water comprises the following steps:
and (one) flocculation precipitation treatment:
and (3) sending 50L of blast furnace gas washing circulating water sewage into a mixing area of a high-density sedimentation tank, wherein the high-density sedimentation tank is provided with the mixing area, the reaction area and the sedimentation area.
The mixing area is divided into two stages, one-stage coarse coagulation treatment and two-stage fine coagulation treatment.
In one placeAdding Ca (OH) with mass concentration of 0.5% into the coarse coagulation zone 2 The aqueous solution was stirred at 200r/min for 12min and the residence time was 15min, controlling the pH at 8.
Adding 5%of polyaluminum chloride (PAC) water solution with the mass concentration of 10-20mg/L or adding aluminum sulfate (Al) into the secondary fine coagulation zone 2 (SO 4 ) 3 ) The dosage is 30mg/L. In addition, 20mL of Polyacrylamide (PAM) aqueous solution with the mass concentration of 1 per mill is added, and the mixture is stirred for 8min at 50-100r/min for 15min. The water after coagulation flows to the bottom of the circular flow guide pipe in the reaction tank, and is uniformly mixed from bottom to top by the stirring paddles in the flow guide pipe.
The water flow in the guide pipe flows into a series reaction unit consisting of a slow stirring tank and a plug flow reaction tank to react so as to obtain larger flocs, and the flocs are quickly precipitated in a precipitation area.
After the water after the reaction enters a sedimentation zone, the flocculated alum flocs are collected into sludge at the lower part of a sedimentation tank and concentrated. The sloping plate is arranged at the upper part of the sedimentation tank and is used for removing redundant alum blossom and ensuring the quality of effluent. The bottom of the sedimentation tank is provided with a mud scraper, and the mud is continuously scraped to promote the concentration of mud in the sedimentation area. The concentrated sludge is deposited into a sludge storage tank and is discharged for sludge dewatering treatment. The sludge dewatering treatment comprises the step of performing filter pressing on sludge by using a filter press.
The effluent of the sedimentation tank flows into a No. 1 middle water tank for standby.
(II) a filtration treatment step
Delivering the effluent of the No. 1 middle water tank into a multi-medium filter of a first-stage filtering device for filtering, wherein the multi-medium filter adopts two-stage filtering, the first-stage filtering filler is anthracite and quartz sand, and the second-stage filtering filler is garnet and quartz sand; the anthracite filler in the primary filler has the height of 400mm, the grain diameter of 0.8-1.5mm, the quartz sand filler has the height of 600mm and the grain diameter of 0.4-0.65mm; the height of quartz sand filler in the secondary filler is 400mm, the grain diameter is 0.7-1.0mm, the height of garnet filler is 600mm, the grain diameter is 0.35mm, and the running flow rate is 6-10m/h.
The effluent after the primary filtration is sent to a secondary filter device, the secondary filter device is a full-automatic self-cleaning filter, the filtering precision is 0.1mm, the filter screen material is 316L stainless steel, and the mesh of the filter screen is 120 meshes. After the filter operates for a period of time, the filter screen is blocked by sludge, so that the water outlet descends, and the filter screen is backwashed. The back flushing period is 8 hours, the back flushing time is 1min30s, and three modes can be started: (1) pressure difference of water inlet and outlet; (2) time; (3) manually and manually cleaning. If the back flushing still can not completely solve the clogging condition of the filter screen, the filter screen is manually removed, the filter screen is soaked in hydrochloric acid solution with the volume fraction of 3% for 4 hours, then the filter screen is washed by high-pressure water, and after treatment, rust, sludge and the like can be thoroughly cleaned.
After the treatment by the secondary filtering device, the suspended matters remained in the water are trapped, and the filtered clean water enters the circulating water tank.
The outlet water temperature of the circulating water tank is not more than 40 ℃. And recycling the water discharged from the circulating water tank to the flushing and cleaning filter press.
The water quality of the blast furnace gas washing circulating water sewage and the circulating water pond effluent are shown in table 1.
Table 1: index of water quality
| Index (I) | Unit (B) | Blast furnace gas washing circulating water sewage | Circulating water pool water outlet |
| pH | / | 7.5-8.0 | 7-8 |
| SS | mg/L | 500-1000 | ≤20 |
| Ca | mg/L | 250-430 | ＜200 |
| Total hardness (as CaCO) 3 Meter (C) | mg/L | 480-1000 | ＜300 |
| Cl | mg/L | ≤200 | ＜120 |
| COD | mg/L | ≤30 | ≤20 |
| Ammonia nitrogen | mg/L | ≤200 | ≤180 |
(III) cleaning filter press
And (3) cleaning a filter press for sludge dewatering treatment in the blast furnace gas washing system by using the effluent of the circulating water tank.
(1) When a plate-and-frame filter press is used in the sludge dewatering treatment process, the plate-and-frame filter press is washed by using the effluent of the circulating water tank.
The filter cloth cleaning modes are divided into three types:
(1) high pressure spray (about 70 bar): the filter cloth is taken out and cleaned in an industrial cleaning machine, and water used in the industrial cleaning machine is water discharged from a circulating water tank.
(2) And (3) manual cleaning: acidifying the filter cloth; the filter cloth is taken out from the chamber and immersed in acid to dissolve residues. The type of acid depends on the substance being filtered. Soaking time is 6-8 hours. After cleaning, the filter cloth is cleaned by using the water discharged from the circulating water tank; this mode is only applicable to filter cloth made of polypropylene and polyamide.
(3) And (3) automatic cleaning: the filter press is provided with an acidification device, and the filter press is soaked for 6-8 hours by using hydrochloric acid with the volume fraction of 3-5%. After acidification, the filter cloth must be cleaned by a high-pressure cleaning device, in order to ensure that the filter cloth is cleaned, firstly checking the dirt blocking condition of the nozzle, washing the nozzle and removing the foreign matters by a brush, and if the washing effect is poor, firstly removing the nozzle pipe and then removing the foreign matters; secondly, checking the angle of the nozzle (adjusting the nozzle to be 10-15 degrees deviated from the axis); finally, the pressure of the cleaning water is checked, and the water pressure is adjusted to 4 kg/cm 2 The above. The filtering effect of the filter cloth can be recovered and the service life can be prolonged by flushing.
The surface of the punctiform or groove filter plate of the plate-and-frame filter press, the filtrate discharge hole and the filtrate channel are all washed by the water discharged from the circulating water tank to prevent solid particles from precipitating.
(2) When a belt filter press is used in the sludge dewatering treatment process, the filter belt and the mesh bag of the belt filter press are washed by using the effluent of the circulating water tank.
After the belt filter press filter belt is used, a certain amount of sludge is adhered to the surface, the filter belt must be cleaned before being reused, two cleaning boxes are arranged, one upper belt and one lower belt are respectively arranged, and the upper surface and the lower surface of the belt are all cleaned, so that two rows of nozzles are used, the using pressure of the nozzles is 0.8MPa, and the flushing water consumption of the belt filter press is more than or equal to 14t/h. The filter belt has a width of 2100mm, a working width of 2000mm and a cleaning water consumption of 220L/min. The nozzle is arranged on the upper stainless steel water pipe and the lower stainless steel water pipe, the hand wheel is arranged on the water pipe of the nozzle, the nozzle can be cleaned by rotating the hand wheel, and the water-proof plate is arranged at the inlet and the outlet of the cleaning box to prevent water from splashing. The water after the filter belt is cleaned is collected in a water tank and automatically flows to a filtrate collecting tank. And (3) after the belt filter press is subjected to filter pressing, dewatering and the mesh bag flushing water automatically flow to a filtrate collecting tank. When the liquid level in the filtrate collecting tank reaches a high liquid level, the self-priming pump in the filtrate collecting tank is automatically started to send sewage to the mixing tank of the high-density sedimentation tank, and when the water level is reduced to a low liquid level, the self-priming pump automatically stops running.
After the filter press is cleaned, the used cleaning device is cleaned again by using the water discharged from the circulating water tank. Otherwise, the sludge may be coagulated in the washing apparatus, and after a long period of time, a problem may occur in re-using the washing apparatus. The filter cloth or the filter belt can bear repeated friction for 60 days after being cleaned, does not deform seriously, can keep good filtering performance, and the interception capability can not change greatly with the duration of time.
Other non-illustrated parts are known in the art.
Claims (10)
1. A method for recycling sewage of blast furnace gas washing circulating water is characterized by comprising the following steps: firstly, carrying out flocculation precipitation treatment and filtration treatment on sewage discharged from blast furnace gas washing circulating water to obtain clean water with the water temperature not exceeding 40 ℃, and then, cleaning a filter press; the blast furnace gas washing circulating water sewage is waste water which is generated by blast furnace wet dust collection and contains a large amount of iron ore powder, coke powder suspended matters, phenol, cyanogen, ammonia nitrogen, sulfide, zinc and other components.
2. The method for recycling the blast furnace gas washing circulating water sewage according to claim 1, which is characterized in that: the flocculation precipitation treatment comprises primary coagulation treatment, secondary fine coagulation treatment and rapid precipitation treatment which are sequentially carried out.
3. The method for recycling the blast furnace gas washing circulating water sewage according to claim 2, which is characterized in that: the primary coagulation treatment comprises the steps of adding Ca (OH) into the sewage of the blast furnace gas washing circulating water 2 Controlling the pH value of the blast furnace gas washing circulating water to be not more than 9 and 180-220r/minStirring at the rotating speed for 10-15min, and then standing for not less than 15min to obtain the sewage after primary coagulation treatment.
4. The method for recycling the blast furnace gas washing circulating water sewage according to claim 2, which is characterized in that: the secondary fine coagulation treatment comprises the following steps: adding coagulant and coagulant aid into the sewage after primary coagulation treatment, stirring for 8-10min at the rotating speed of less than or equal to 100r/min so as to enable the added coagulant aid and coagulant aid to be rapidly dispersed, and fully and uniformly mixing with the sewage; standing for at least 15min to form small flocs in the sewage; the coagulant comprises polyaluminum chloride and/or aluminum sulfate, and the coagulant aid comprises polyacrylamide.
5. The method for recycling the blast furnace gas washing circulating water sewage according to claim 2, which is characterized in that: the rapid sedimentation treatment is to drain the sewage after the secondary fine coagulation treatment to the bottom of a flow guide pipe in a reaction tank, stir and mix the sewage from bottom to top, and then react in a form of slow stirring and plug flow so as to form large flocs in the sewage, thereby realizing rapid sedimentation.
6. The method for recycling the blast furnace gas washing circulating water sewage according to any one of claims 1 to 5, characterized by comprising the steps of: carrying out sludge dewatering treatment on the sludge obtained after the flocculation precipitation treatment is finished; the sludge dewatering treatment comprises the step of carrying out pressure filtration on sludge by using the pressure filter, and returning the sewage after pressure filtration to the flocculation precipitation treatment step for recycling.
7. The method for recycling the blast furnace gas washing circulating water sewage according to claim 1, which is characterized in that: the filtering treatment comprises a primary filtering treatment and a secondary filtering treatment which are sequentially carried out, wherein the primary filtering treatment adopts a multi-medium filter to filter the effluent after the flocculation precipitation treatment is finished, and the secondary filtering treatment adopts a filter with the filtering precision of 0.1mm and the mesh of a filter screen of 120 meshes to filter the effluent after the primary filtering treatment; wherein, the multi-medium filter adopts a two-stage sub-filtering mode, the filler adopted by the first-stage sub-filtering is anthracite and quartz sand, and the filler adopted by the second-stage sub-filtering is garnet and quartz sand.
8. The method for recycling the blast furnace gas washing circulating water sewage according to claim 1, which is characterized in that: the water quality indexes of the clean water obtained after the flocculation precipitation treatment and the filtration treatment comprise: the pH value is 7-8, SS is less than or equal to 20mg/L, ca is less than 200mg/L, and the total hardness is CaCO 3 The total concentration is less than 300mg/L, cl is less than 120mg/L, COD is less than or equal to 20mg/L, and ammonia nitrogen is less than or equal to 180mg/L.
9. The method for recycling the blast furnace gas washing circulating water sewage according to claim 1, which is characterized in that: the filter press comprises a plate-and-frame filter press or a belt filter press; the clean water obtained after the flocculation precipitation treatment and the filtration treatment is used for cleaning filter cloth, filter plate surfaces, filtrate discharge holes and filtrate channels of a plate-and-frame filter press or filter belts and mesh bags of a belt filter press.
10. The method for recycling the blast furnace gas washing circulating water sewage according to claim 9, which is characterized in that: and the effluent water after the sludge dewatering treatment of the filter press and the sewage generated in the cleaning process of the filter press are returned to the flocculation precipitation treatment step for recycling.
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| CN202311831906.3A CN117800462A (en) | 2023-12-28 | 2023-12-28 | Method for recycling sewage discharged by blast furnace gas washing circulating water |
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| CN202311831906.3A CN117800462A (en) | 2023-12-28 | 2023-12-28 | Method for recycling sewage discharged by blast furnace gas washing circulating water |
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