CN111892113A - Desulfurization wastewater treatment system with ammonia nitrogen stripping function - Google Patents
Desulfurization wastewater treatment system with ammonia nitrogen stripping function Download PDFInfo
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- 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
- C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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- C02F9/00—Multistage treatment of water, waste water or sewage
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- 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
- C02F1/5281—Installations for water purification using chemical agents
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- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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- C02F2101/00—Nature of the contaminant
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- C02F2101/16—Nitrogen compounds, e.g. ammonia
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- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
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- C02F2301/043—Treatment of partial or bypass streams
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- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/02—Softening water by precipitation of the hardness
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/02—Softening water by precipitation of the hardness
- C02F5/06—Softening water by precipitation of the hardness using calcium compounds
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Abstract
The invention provides a desulfurization wastewater treatment system with an ammonia nitrogen stripping function, which comprises a pretreatment unit, a softening unit and an ammonia nitrogen stripping unit which are sequentially connected; the pretreatment unit is used for pretreating the desulfurization wastewater; the softening unit is used for carrying out scale-causing ion reduction treatment on the pretreated desulfurization wastewater; the ammonia nitrogen stripping unit is used for carrying out ammonia nitrogen stripping treatment on the softened desulfurization wastewater; the ammonia nitrogen stripping unit comprises a softening product water tank, an ammonia nitrogen stripping tower, a waste gas collecting device and a deamination product water tank; the softening unit is connected with a water inlet of the softening water production tank; the water outlet of the softening water production tank is connected with the water inlet of the ammonia nitrogen stripping tower; the softening water production tank is provided with a blowing-off auxiliary agent feeding port; an exhaust port of the ammonia nitrogen stripping tower is connected with a waste gas collecting device; the water outlet of the ammonia nitrogen stripping tower is connected with a deamination production water tank. The system can be used for primary blowing-off water production ammonia nitrogen to reach the standard under the conditions of lower pH value, lower gas-liquid ratio and no need of heating, deamination gas is directly reused for flue gas denitration, and denitration ammonia injection amount is reduced.
Description
Technical Field
The invention relates to the technical field of wastewater treatment, in particular to a desulfurization wastewater treatment system with an ammonia nitrogen stripping function.
Background
Coal-fired power plants using coal as a fuel can produce harmful substances such as smoke, sulfur dioxide, NOx and the like during combustion. In order to control NOx in discharged flue gas, a flue gas denitration process is commonly implemented in coal-fired power plants in China, and ammonia nitrogen in flue gas desulfurization wastewater generally exceeds the standard due to ammonia escape. The desulfurization wastewater is wastewater which has complex and variable water quality components, frequent fluctuation and difficult treatment in the conventional wastewater of a coal-fired power plant, has the characteristics of strong corrosivity, high salt content, high hardness, high suspended matters, COD (chemical oxygen demand), heavy metals, fluorides, sulfides, ammonia nitrogen, nitrates, nitrites, silicon and the like, particularly contains heavy metals and metalloid ions such as Pb, Cd, Cr, Ni, Hg and the like which are strictly controlled by national and world health organizations, has the water temperature of about 50 ℃, is directly discharged to greatly pollute the environment, and can be discharged when the wastewater is required to be treated to reach the corresponding standard.
The related requirements of 'treating and recycling the desulfurization wastewater, and discharging the desulfurization wastewater after reaching the standard when the environmental evaluation allows' and 'treating the desulfurization wastewater deeply when the zero discharge requirement exists' are provided in DL/T5046-2018 power plant wastewater treatment design technical regulation issued in 2018 in China. The current standard of standard emission execution of desulfurization wastewater in China is 'limestone-gypsum wet desulfurization wastewater water quality control index of thermal power plant' (DL/T997-2006) and GB8978-1996 'pollutant comprehensive emission standard'.
At present, the standard discharge treatment process mainly comprises a physical precipitation method, a chemical precipitation method, a biological treatment method, a zero-valent iron method and the like, and the main process of industrial application is the chemical precipitation method. The best feasible technologies issued by the European Union congress and council mainly comprise neutralization, flocculation and filtration clarification technologies; the best feasible technology issued by the United states environmental protection agency mainly comprises a physical precipitation method, a chemical precipitation method, a biological treatment method and an artificial wetland; chemical precipitation method is commonly adopted in coal-fired power plants in China. Because the water quality components of the desulfurization wastewater of the coal-fired power plant are complex and changeable, a multistage treatment process is generally adopted at home and abroad to remove water pollutants, the process flow is long, the equipment investment is large, and the operating cost is high.
Patent CN201721234076.6 discloses a novel high-efficient flocculation treatment system of desulfurization waste water, and the high-efficient flocculation technology who provides has realized only throwing a compound high-efficient flocculation medicament, has accomplished the system water in an hour, because high-efficient flocculation technology can shorten process flow by a wide margin, reduces equipment investment and working costs, is the high-efficient low-cost preliminary treatment process technology of coal fired power plant desulfurization waste water.
However, the above-mentioned desulfurization wastewater high-efficiency flocculation treatment system cannot remove ammonia nitrogen in the desulfurization wastewater. Therefore, a desulfurization wastewater treatment system with ammonia nitrogen stripping function is urgently needed.
Disclosure of Invention
In order to solve the problem that the existing desulfurization wastewater high-efficiency flocculation treatment system cannot remove ammonia nitrogen in the desulfurization wastewater in the background art, the invention provides a desulfurization wastewater treatment system with an ammonia nitrogen stripping function, which comprises a pretreatment unit, a softening unit and an ammonia nitrogen stripping unit which are sequentially connected;
the pretreatment unit is used for pretreating desulfurization wastewater;
the softening unit is used for carrying out scale-causing ion reduction treatment on the pretreated desulfurization wastewater;
the ammonia nitrogen stripping unit is used for carrying out ammonia nitrogen stripping treatment on the softened desulfurization wastewater;
the ammonia nitrogen stripping unit comprises a softening product water tank, an ammonia nitrogen stripping tower, a waste gas collecting device and a deamination product water tank; the softening unit is connected with a water inlet of the softening water production tank; the water outlet of the softening water production tank is connected with the water inlet of the ammonia nitrogen stripping tower; the softening water production tank is provided with a blowing-off auxiliary agent feeding hole; the exhaust port of the ammonia nitrogen stripping tower is connected with the waste gas collecting device; and the water outlet of the ammonia nitrogen stripping tower is connected with the ammonia nitrogen production water tank.
Furthermore, a demisting mechanism, an atomizing spray header, a packed bed and a gas generating mechanism are sequentially arranged in the ammonia nitrogen stripping tower from top to bottom; the exhaust port of the ammonia nitrogen stripping tower is positioned at the top; the water outlet of the ammonia nitrogen stripping tower is positioned at the bottom; the atomization spray header is connected with a water outlet of the softening water production tank.
Further, the gas generating mechanism comprises a gas inlet, a flow guide plate and a gas inlet distribution modulator; the baffle is disposed between the gas inlet and the inlet gas distribution modulator; the air entering from the air inlet is guided by the guide plate to flow to the air inlet distribution modulator, and the air inlet distribution modulator is used for adjusting the air to be in a cyclone flow state and rising;
the air inlet is connected with an air filter; the air filter is connected with the fan;
the upper part and the lower part of the gas inlet distribution modulator are hemispherical, the middle section is an isometric cylindrical hollow pipe, and the middle section is sleeved with an impeller.
Further, the packed bed consists of a plurality of packing layers; from bottom to top, the specific surface area of unit volume of the filler is increased by 1.25 to 2.5 times layer by layer;
the filler of the packed bed is made of corrosion-resistant and anti-fouling plastic materials.
Furthermore, the packed bed is divided into two parts, wherein the upper part adopts regular packing, and the lower part adopts bulk packing.
Further, the demisting structure comprises a three-level ridge type demister, a washing device and a washing control system;
the flushing control system comprises a differential pressure sensor, a differential pressure transmitter and a control circuit board; the upper side and the lower side of each ridge type demister are respectively provided with the differential pressure sensor; two adjacent differential pressure sensors are connected with the same differential pressure transmitter; the pressure difference transmitter is electrically connected with the control circuit board.
Furthermore, each stage of ridge type demister is formed by combining a plurality of demister blades; the demister blades are provided with water collecting barbs; liquid collecting grooves are formed in the bottoms of the ridge type demisters at all levels; each liquid collecting groove is connected with the same liquid collecting pipeline; and the liquid collecting pipeline is connected with the bottom of the ammonia nitrogen stripping tower.
Further, an exhaust gas distribution modulator is arranged at an exhaust port of the ammonia nitrogen stripping tower; the lower part of the exhaust gas distribution modulator is hemispherical, and the upper part and the middle part are cylindrical hollow pipes with the same diameter; the middle section of the exhaust gas distribution modulator is sleeved with an impeller; and a plurality of airflow guide blades are arranged at an exhaust port of the ammonia nitrogen stripping tower.
Further, the ammonia nitrogen stripping unit also comprises a stripping auxiliary agent storage tank; and the blow-off additive storage box is connected with a blow-off additive feeding hole of the softening water production tank.
Further, the ammonia nitrogen stripping auxiliary agent storage tank stores the ammonia nitrogen stripping auxiliary agent; the ammonia nitrogen stripping auxiliary agent comprises, by weight, 15% -35% of octadecyl trimethoxy silane, 15% -35% of fluorocarbon surfactant, 10% -30% of cyclohexanone, 10% -30% of cyclopentane and 10% -15% of hydroxymethyl fiber sodium salt; the octadecyl trimethoxy silane and the fluorocarbon surfactant are compounded according to the ratio of 1: 1.
The desulfurization wastewater treatment system with the ammonia nitrogen stripping function provided by the invention can reach the standard of ammonia nitrogen in primary stripping produced water under the conditions of lower pH value and lower gas-liquid ratio without heating, the deamination gas is directly reused for flue gas denitrification, the denitrification ammonia injection amount is synchronously reduced, a deamination recovery and crystallization solidification facility is not required to be built, and the equipment investment and operation and maintenance cost can be greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic block diagram of a desulfurization wastewater treatment system with ammonia nitrogen stripping function according to the present invention;
FIG. 2 is a schematic block diagram of an ammonia nitrogen stripping unit;
FIG. 3 is a block schematic diagram of a control system;
FIG. 4 is a schematic structural diagram of an ammonia nitrogen stripping tower;
FIG. 5 is a schematic illustration of a defogging structure;
FIG. 6 is a schematic diagram of the structure of the inlet gas distribution modulator;
FIG. 7 is a schematic diagram of an exhaust gas distribution modulator disposed at an exhaust port.
Reference numerals:
100 pretreatment unit 200 softening unit 300 ammonia nitrogen stripping unit
310 soften and produce 320 ammonia nitrogen of water tank and blow off tower 321 defogging mechanism
322 atomizing spray head 323 packed bed 324 gas generating mechanism
325 gas distribution modulator 326 ridge type demister 327 flushing device
328 differential pressure sensor 329 differential pressure transmitter 330 exhaust gas collecting device
Exhaust gas distribution modulator for 351 liquid-gathering groove 352 of 340 deamination production water tank
510 human interface station 520 system network 531 preprocessing unit process control station
532 softening unit process control station 533 ammonia nitrogen stripping unit control station
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In order to make the technical personnel in the field have clearer understanding on the ammonia nitrogen stripping auxiliary agent in the invention, the ammonia nitrogen stripping auxiliary agent is explained, and the ammonia nitrogen stripping auxiliary agent can change the occurrence form of ammonia nitrogen in the desulfurization wastewater and reduce NH3Binding force with water molecules and increasing NH in liquid phase3The mass transfer rate of (2). NH dissolved in desulfurization waste water3And various NH exists between water molecules3…H2The hydrogen bond cluster structure of the O system has strong intermolecular binding force and is not beneficial to NH3Mass transfer from liquid to gas phase. The research shows that: contains a large amount of O, H, OH, CH2Substances which are isoradical and active radical, on the one hand, change NH in the wastewater by the action of electrostatic attraction and repulsion3…H2The O system hydrogen bond cluster structure breaks the original NH in the wastewater3…H2Hydrogen bond cluster structure of O system to destroy water molecule and NH3Intermolecular binding force, NH3The molecules completely get rid of the binding force of water molecules and are almost completely separated from the wastewater. On the other hand, NH in the liquid phase can be increased3Mass transfer rate of, accelerating NH3Mass transfer processes in the liquid phase. Because the ammonia nitrogen stripping auxiliary agent changes the occurrence form of ammonia nitrogen in the desulfurization wastewater and reduces NH3The binding force between the catalyst and water molecules is increased, and NH in a liquid phase is increased3The mass transfer rate of (2). The ammonia nitrogen in the primary blow-off produced water can be reduced to be less than or equal to 5mg/L under the conditions of lower pH value (pH is less than or equal to 10) and lower gas-liquid ratio (1500: 1). In general, the pH value of the deamination water is less than or equal to 9, and acid liquor (such as hydrochloric acid) is not needed to be added to adjust the pH value, so that the discharge standard can be met.
As shown in fig. 1, the invention provides a desulfurization wastewater treatment system with ammonia nitrogen stripping function, which comprises a pretreatment unit 100, a softening unit 200 and an ammonia nitrogen stripping unit 300 which are connected in sequence;
the pretreatment unit 100 is used for pretreating desulfurization wastewater;
the softening unit 200 is used for carrying out scale-causing ion reduction treatment on the pretreated desulfurization wastewater;
the ammonia nitrogen stripping unit 300 is used for performing ammonia nitrogen stripping treatment on the softened desulfurization wastewater;
the ammonia nitrogen stripping unit 300 comprises a softening product water tank 310, an ammonia nitrogen stripping tower 320, a waste gas collecting device 330 and a deamination product water tank 340; the softening unit 200 is connected with the water inlet of the softening water production tank 310; the water outlet of the softening water production tank 310 is connected with the water inlet of the ammonia nitrogen stripping tower 320; the softening water production tank 310 is provided with a blowing-off auxiliary agent feeding hole; the exhaust port of the ammonia nitrogen stripping tower 320 is connected with the waste gas collecting device 330; the water outlet of the ammonia nitrogen stripping tower 320 is connected with the deamination water tank 340.
In specific implementation, as shown in fig. 1-3, the pretreatment unit 100 employs a novel desulfurization wastewater high-efficiency flocculation treatment system of patent 201721234076.6 or a granulation clarification desulfurization wastewater treatment system of patent 201721240150.5, the process system described in the process system utilizes micro-nano environmental pollutants and micro-interface behaviors thereof, and employs a high-efficiency flocculation process technology, and only directly adds a composite high-efficiency flocculation reagent, and can effectively remove suspended matters, fluorides, sulfides and heavy metal ions in wastewater through flocculation reaction, reduce chemical oxygen consumption, and effectively adjust pH value, and the clarified produced water reaches or exceeds DL/T997-2006 standard, and completes water production in one hour, thereby greatly shortening process flow, reducing equipment investment and operating cost, and the detailed description in the patent is provided.
The water produced by the pretreatment unit 100 overflows to the softening unit 200, and the softening unit 200 reduces scale ions such as calcium, magnesium and the like in the desulfurization wastewater by adopting the traditional lime-sodium carbonate softening technology. The softening unit 200 is a two-stage reaction precipitation and clarification process, calcium hydroxide is added into a first-stage reactor to adjust the pH value of the wastewater, so that part of heavy metal ions and Mg in the desulfurization wastewater2+And silicon and other pollutants and part of scale-causing ions generate precipitates; sodium carbonate is added into the secondary reactor to ensure that Ca in the wastewater is2+Formation of calcium carbonate precipitateRemoving Ca from the wastewater2+Finally, solid-liquid separation is carried out through the sedimentation clarification tank, sludge is separately treated, and finally the softening pretreatment effect of the desulfurization wastewater is realized. The process also has good effect of removing silicon in the wastewater, and the silicon content is reduced mainly due to the fact that the silicon content is reduced along with Ca (OH)2Form a plurality of Mg (OH) with extremely large active surface area2Precipitates capable of adsorbing SiO contained in a solution in a large amount2Thereby causing a chemical reaction of the formula 2SiO2+Mg(OH)2＝Mg(HSiO3)2. In addition, SO in the desulfurization waste water4 2-、F-Can also combine with calcium ions in lime to generate CaSO4With CaF2And removing the precipitate. The pH value is generally adjusted to 10 for the ammonia nitrogen stripping requirement of the subsequent process.
The softening unit 200 mixes the chemically softened sludge with the pretreated flocculated sludge and pumps the mixture to the dehydrator 400 for dehydration (shared with the pretreatment unit 100), the filtrate of the dehydrator 400 returns to the wastewater inlet of the "one-step" efficient flocculation device for circular treatment, and the sludge cake generated by the dehydrator 400 is disposed as solid waste.
The raw water of the desulfurization wastewater is pretreated and softened, the PH of softened produced water is adjusted to 10, the softened produced water is pumped to a softened produced water tank 310, an ammonia nitrogen stripping auxiliary agent is added according to the proportion of 10-20mg/L, and the mixture is fully and uniformly mixed. The softened water tank 310 delivers the treated desulfurization wastewater to the ammonia nitrogen stripping tower 320 for ammonia nitrogen stripping treatment, the treated nitrogen-containing air enters the waste gas collecting device 330 through the exhaust port of the ammonia nitrogen stripping tower 320, and the deamination water enters the deamination water tank 340 through the water outlet of the ammonia nitrogen stripping tower 320.
Further, the control system of the desulfurization wastewater treatment system adopts a distributed control system, and the system structure is divided into three most basic parts: a human interface station 510, a system network 520, and a process control station. A redundant fault-tolerant double-ring fast Ethernet is adopted as a main real-time network of the system.
The process control station is arranged in the desulfurization wastewater pretreatment unit, the softening unit and the ammonia nitrogen stripping unit, comprises a pretreatment unit process control station 531, a softening unit process control station 532 and an ammonia nitrogen stripping unit control station 533, performs monitoring, on-site/automatic control, is connected to the Ethernet switch through 100Mbps redundant fault-tolerant Ethernet, and is connected with the Ethernet switch.
The human-computer interface station 510 enables an operator to monitor the operation parameters, states, alarms and operation videos of the pretreatment unit 100, the softening unit 200 and the ammonia nitrogen stripping unit 300 through a human-computer interface, analyze the variation trend of various parameters, and recall the history records of various parameters; an operation operator can adjust the parameter, state setting, operation mode and control logic of the pretreatment unit 100, the softening unit 200 and the ammonia nitrogen stripping unit 300 through a human-computer interface; and the operation operators control the operation modes, start and stop of the equipment and the like of the operation pretreatment unit 100, the softening unit 200 and the ammonia nitrogen stripping unit 300 through a human-computer interface.
The system network 520 is a 100Mbps redundant fault-tolerant Ethernet network and is used for communication between the human-computer interface station 510 and the preprocessing unit process control station 531, between the softening unit process control station 532 and the ammonia nitrogen stripping unit control station 533, and between the process control stations.
A pretreatment unit process control station 531, a softening unit process control station 532 and an ammonia nitrogen stripping unit control station 533, which are used for realizing the functions of acquisition of measured data, control and operation of process parameters, alarm and interlocking of equipment faults and various on-site control.
It should be noted that the present invention does not relate to the improvement of the program, and a person skilled in the art can select the existing industrial control system to apply according to specific needs.
In the above embodiment, preferably, the ammonia nitrogen stripping tower 320 is internally provided with a demisting mechanism 321, an atomizing spray header 322, a packed bed 323 and a gas generating mechanism 324 in sequence from top to bottom; the exhaust port of the ammonia nitrogen stripping tower 320 is positioned at the top; the water outlet of the ammonia nitrogen stripping tower 320 is positioned at the bottom; the atomization spray header 322 is connected with the water outlet of the softening water production tank 310.
In specific implementation, as shown in fig. 4-7, a demisting mechanism 321, an atomizing spray header 322, a packed bed 323 and a gas generating mechanism 324 are sequentially arranged in the ammonia nitrogen stripping tower 320 from top to bottom;
the demisting mechanism 321 is used for efficiently removing fine liquid droplets in the gas;
the atomizing spray head 322 is connected with the softening water production tank 310 through a pipeline;
the filler bed 323 is filled with the filler, the ammonia-containing wastewater is atomized and sprayed from top to bottom, on one hand, the ammonia-containing wastewater is atomized and forms a micron-sized liquid film on the surface of the high-surface-area filler, and NH is accelerated3Mass transfer from the liquid phase to the gas phase; on the other hand, the air is modulated into dry air in a cyclone flow state from the upstream to the downstream, so that the direct mass transfer process is strengthened, and NH in a liquid phase is further increased3Mass transfer rate of, accelerating NH3In the process of mass transfer from a liquid phase to a gas phase, ammonia nitrogen in the wastewater is gradually blown off and enters the gas phase from the liquid phase;
the gas generating mechanism 324 is used for being connected with an external air filter, air is conveyed to the air filter by the fan, and the air rises in a cyclone flow state through the gas generating mechanism 324;
when in use, air is conveyed to the gas generating mechanism 324 through the air filter and rises in a cyclone flow state; the wastewater treated by the softened water production tank 310 is conveyed to an atomizing spray header 322 by a water pump for spraying; the descending liquid and ascending air are subjected to ammonia nitrogen stripping in a packed bed 323; the ammonia water is discharged from a water outlet at the bottom of the ammonia nitrogen stripping tower 320; after the ascending nitrogen-containing gas-liquid mixture passes through the demisting mechanism 321, liquid drops are removed, and nitrogen-containing air is discharged from an exhaust port at the top of the ammonia nitrogen stripping tower 320;
further, the gas generating mechanism 324 includes a gas inlet, a baffle, and a gas inlet distribution modulator 325; the baffle is disposed between the gas inlet and the inlet gas distribution modulator 325; the air entering from the air inlet is guided by the guide plate to flow to the air inlet distribution modulator 325, and the air inlet distribution modulator 325 is used for adjusting the air to be in a cyclone flow state and rising;
the air inlet is connected with an air filter; the air filter is connected with the fan;
the upper part and the lower part of the gas inlet distribution modulator 325 are hemispherical, the middle section is an isometric cylindrical hollow pipe, and the middle section is sleeved with an impeller.
Specifically, the gas generating mechanisms 324 are channel bins, and each gas generating mechanism 324 corresponds to one gas inlet and one inlet gas distribution modulator 325; the ammonia nitrogen stripping tower 320 can adopt a single-side or multi-side arrangement of air inlets, each air inlet corresponds to an air inlet distribution modulator 325 one by one, and a plurality of gas generation mechanisms 324 are arranged according to actual requirements; a guide plate is arranged between the inlet gas distribution modulator 325 and the gas inlet, the guide plate is a curved inclined plate, and the guide plate has the main function of modulating horizontal gas flow entering from the gas inlet into vertical gas flow and guiding the vertical gas flow to the inlet gas distribution modulator 325, and the vertical gas flow is processed and then ascended to a packed bed in a cyclone flow state.
It should be noted that the distance from the horizontal plane at the bottom of the intake air distribution modulator 325 to the upper edge of the intake port is greater than or equal to the pipe diameter of the intake pipe. The deamination wastewater can be deposited in a deamination wastewater collecting cone hopper positioned at the lower part of the ammonia nitrogen stripping tower 320 through an inlet gas distribution modulator 325. Except the air outlet, the rest parts of the upper part of the gas generating mechanism 324 are sealed by a large-angle inclined plate to prevent the airflow from escaping. The distance from the upper edge of the gas generating means 324 to the lower edge of the packed bed 323 is determined by design calculations.
Further, the packed bed 323 consists of a plurality of packing layers; from bottom to top, the specific surface area of unit volume of the filler is increased by 1.25 to 2.5 times layer by layer;
the packing of the packed bed 323 is made of corrosion-resistant and anti-fouling plastic materials.
Further, the packed bed 323 is divided into two parts, the upper part adopts structured packing, and the lower part adopts bulk packing.
Specifically, the packed bed 323 is structurally divided into several layers, typically 2-8 layers, often four layers. The filler is made of corrosion-resistant and anti-fouling plastic materials, and is usually made of PP polypropylene materials. The specific surface area of the unit volume of the filler layer from bottom to top is gradually increased by 1.25 to 2.5 times. The packed bed 323 is divided into two parts, the upper part adopts regular packing, and the lower part adopts bulk packing.
The regular packing is pulse regular packing and features that multiple pulses of gas and liquid are realized inside one disc of packing to strengthen the turbulence of gas and liquid inside the regular packing, raise the separation efficiency greatly and lower resistance. The pulse structured packing is characterized in that 1-4 pulse areas are arranged in one packing disc height according to the movement characteristics of gas in a structured flow channel, the gas-liquid flow direction of the pulse areas is the same as the gas-liquid flow direction in a tower, and the gas-liquid vertically moves up and down in the pulse areas. In the pulse area, the ascending airflow gradually changes from the inclined ascending direction to the vertical ascending and then gradually changes to the inclined ascending direction, and the filler inclination angle changing process forms a pulse motion of gas phase and liquid phase. In a disc of pulse structured packing, multiple pulse motion of gas and liquid can be realized in one packing unit according to the load of the gas and liquid, the pressure drop of the packing layer is reduced, and meanwhile, the turbulent mass transfer of the gas phase and the liquid phase in a pulse area improves the separation efficiency.
The pulse structured packing has the characteristics that:
1. the efficiency is high, the gas-liquid turbulence in the filler strengthens mass transfer, the mass transfer efficiency is obviously improved, and the efficiency can be improved by more than 5 percent compared with the efficiency of the common structured filler.
2. The pressure is reduced, and the interface resistance of a common packing layer is effectively eliminated due to the smooth transition of the gas-liquid flow direction in the packing, so that the pressure drop is reduced by about 10 percent compared with that of a common structured packing.
3. The flux is large, and the flux can be improved by more than 30 percent compared with the flux of the common structured packing because the accumulation of a liquid phase in the packing is effectively avoided.
The bulk filler is selected from high-efficiency plastic fillers, and has the following size: 25x30 mm-83 x95 mm; effective specific surface area: 240 + 360m2/m3(ii) a Number of units volume: 1000-3(ii) a Porosity: 45% -95%; weight: the polypropylene material is 40-150kg/m3(ii) a PVDF material 80-270kg/m3(ii) a Number of liquid drops that can be created: 770000-3. Alternatively, a ring packing of Telapreder is also selected.
Further, the demister structure 321 includes a three-stage ridge demister 326, a flushing device 327, and a flushing control system;
the flushing control system comprises a differential pressure sensor 328, a differential pressure transmitter 329 and a control circuit board; the upper side and the lower side of each ridge type demister 326 are respectively provided with the differential pressure sensor 328; two adjacent differential pressure sensors 328 are connected with the same differential pressure transmitter 329; the differential pressure transmitter 329 is electrically connected to the control circuit board.
Further, each stage of the ridge mist eliminator 326 is composed of a plurality of mist eliminator blades; the demister blades are provided with water collecting barbs; the bottom of each ridge type demister 326 is provided with a liquid collecting groove 351; each liquid collecting groove 351 is connected with the same liquid collecting pipeline; the liquid collecting pipeline is connected with the bottom of the ammonia nitrogen stripping tower 320.
Specifically, the ridge type demister 326 has a conventional shape formed by a plurality of module blades, the thickness of the blade wall is more than or equal to 3mm, the surface of the blade is flat and smooth, the chemical and physical properties are excellent, and the corrosion resistance is strong; the third-stage ridge demister 326 is a first-stage ridge demister, a second-stage ridge demister and a third-stage ridge demister from bottom to top; the first-stage ridge type demister has the module blade spacing of 30-26 mm; the second-stage ridge type demister has the module blade spacing of 25-21 mm; the third-stage ridge type demister has the module blade interval of 23-19 mm; a flushing device 327 is arranged above each ridge type demister 326, the flushing devices 327 are connected into a whole by pipelines and are connected with a flushing main pipeline, and ammonia-removing water is used for flushing; the bottom of each ridge type demister 326 is provided with a liquid collecting groove 351, the liquid collecting grooves 351 are connected into a whole by a pipeline and used for collecting liquid and discharging the liquid to a liquid collecting conical hopper at the bottom of the ammonia nitrogen stripping tower 320; the deamination waste water collecting cone hopper is arranged below the guide plate at the air inlet, the discharge valve is arranged below the deamination waste water collecting cone hopper, and the deamination waste water is drained by gravity flow.
The flushing control system is provided with a differential pressure sensor 328, a differential pressure transmitter 329 and a control circuit board, and controls the flushing start-stop and flushing time of the flushing control system by detecting the differential pressure of each ridge type demister 326.
Further, an exhaust gas distribution modulator 352 is arranged at an exhaust port of the ammonia nitrogen stripping tower 320; the lower part of the exhaust gas distribution modulator 352 is hemispherical, and the upper part and the middle part are cylindrical hollow pipes with the same diameter; the middle section of the exhaust gas distribution modulator 352 is sleeved with an impeller; and a plurality of airflow guide blades are arranged at the exhaust port of the ammonia nitrogen stripping tower 320.
Specifically, the exhaust port of the ammonia nitrogen stripping tower 320 is provided with an exhaust gas distribution modulator 352, the exhaust gas distribution modulator 352 and the intake gas distribution modulator 325 are located on the same central line, and the ammonia nitrogen stripping tower has the main function of enabling air flow to be distributed into a cyclone flow state which rotates around atomized liquid drops, achieving efficient mass transfer, enabling inlet and outlet air to be more uniform, greatly improving the space utilization rate in the tower, and effectively reducing the height of the tower. The flow velocity of the exhaust port of the ammonia nitrogen stripping tower 320 is 8-30m/s, and optionally, the flow, pressure and thermometer are configured at the exhaust port of the ammonia nitrogen stripping tower 320. And the exhaust gas distribution modulator 352 to the 90-degree turning position of the exhaust port is provided with an airflow guide blade, so that the gas is horizontally turned from the vertical direction.
In the implementation of the above embodiment, preferably, the ammonia nitrogen stripping unit 300 further comprises a stripping aid storage tank; the blowing-off agent storage tank is connected with the blowing-off agent feeding hole of the softening water production tank 310.
Further, the blowing-off auxiliary agent storage tank 360 stores ammonia nitrogen blowing-off auxiliary agent; the ammonia nitrogen stripping auxiliary agent comprises, by weight, 15% -35% of octadecyl trimethoxy silane, 15% -35% of fluorocarbon surfactant, 10% -30% of cyclohexanone, 10% -30% of cyclopentane and 10% -15% of hydroxymethyl fiber sodium salt; the octadecyl trimethoxy silane and the fluorocarbon surfactant are compounded according to the ratio of 1: 1.
It should be noted that, in the implementation of the above embodiment, the main operation parameters of the ammonia nitrogen stripping tower are as follows:
the inlet air temperature of the tower body is as follows: normal temperature;
tower body air inlet flow rate: 8-30 m/s;
the liquid inlet temperature of the tower body is as follows: 35-40 ℃;
gas-liquid ratio: 1500: 1;
effective specific surface area of filler: 100-800m2/m3；
Number of filler-induced droplets: more than or equal to 500000/m3；
Cyclone flow state flow velocity: 1-4.9 m/s;
tower exhaust flow rate: 8-30 m/s;
operating pressure: normal pressure;
water distribution atomized droplet particle size: 100-;
the water quality requirement of inlet water is as follows: TSS is less than or equal to 70 mg/L; the supersaturation index SI of the calcium sulfate is less than or equal to 4; the oil content is less than or equal to 20 mg/L; the silicon content is less than or equal to 50 mg/L; the ammonia nitrogen is less than or equal to 1500 mg/L.
Water quality of deamination: the ammonia nitrogen is less than or equal to 5 mg/L.
Compared with the prior art and the advancement of the process, the invention is concretely as follows:
1. comparison of pretreatment as shown in tables 1, 2 and 3,
TABLE 1 comparison of Process technologies
TABLE 2 comparison of economics
TABLE 3 comparison of environmental benefits
2. Ammonia nitrogen stripping comparison
(1) The process technology comprises the following steps: in the traditional ammonia nitrogen direct stripping process, 1) the pH of the wastewater needs to be adjusted to be strong alkali (the pH is more than 11.5) before stripping, and a proper amount of acid needs to be added to adjust the pH to be less than 9 after stripping, so that the consumption of the acid and the alkali is high, and the treatment cost is increased; 2) because the ammonia nitrogen removal efficiency is low at low temperature, the operation temperature is generally required to be heated to about 50 ℃, waste water heating equipment is required, and a certain amount of heat energy is consumed; 3) the general gas-liquid ratio is 6000:1, the gas consumption is high, the energy consumption of a fan is high, and the operation cost is high; 4) the blown-off ammonia gas is generally absorbed by sulfuric acid, a corresponding ammonia gas absorption system and evaporation crystallization equipment need to be built, the blown-off ammonia gas is absorbed by the sulfuric acid to generate liquid ammonium sulfate, and the liquid ammonium sulfate is evaporated and crystallized to generate ammonium sulfate powder resources for utilization. 5) The traditional ammonia nitrogen direct stripping process usually needs to set multistage stripping to meet the requirement of the emission standard, and the equipment investment and the operating cost are higher.
The invention adopts two process technologies of a high-surface-area packed tower and an ammonia nitrogen high-efficiency stripping auxiliary agent (the addition amount of the auxiliary agent is small, generally 10-20mg/L, but the effect is obvious), and NH is greatly reduced by changing the occurrence form of ammonia nitrogen in the desulfurization wastewater3Binding force with water molecules and strengthening NH3Mass transfer rate from liquid to gas phase. 1) The ammonia nitrogen stripping operation requirement can be met under the condition that the pH value is less than or equal to 10, the pH value of the ammonia water is less than or equal to 9 generally, and acid liquor does not need to be added (such as: hydrochloric acid) to adjust the pH value, and the discharge standard can be met. Greatly reduces the consumption of acid and alkali and reduces the treatment cost; 2) in view of the fact that the liquid discharge temperature of the desulfurization waste water is generally 50-55 ℃, the preposed process equipment adopts proper heat preservation measures, so that the temperature of softened produced water can reach 35-40 ℃, and the requirement of ammonia nitrogen stripping on the operating temperature can be met. The investment for building heating facilities is not needed, and the heating heat energy is not needed to be consumed. Further reducing the equipment investment and the operation and maintenance cost. 3) The operation gas-liquid ratio of the invention is 1500:1, the gas consumption is only 25% of the traditional ammonia nitrogen direct stripping process, the fan investment and energy consumption are greatly reduced, and the operation cost is further reduced; 4) for the blown-off ammonia gas, the ammonia-containing air is sent to the hearth along with secondary air of the coal-fired power plant for denitration, the deamination gas is directly reused for flue gas denitration, the denitration ammonia injection amount is synchronously reduced, a corresponding ammonia gas absorption system and evaporation crystallization equipment do not need to be built, and the equipment investment and the operation and maintenance cost are further reduced. 5) The invention can be used in the conditions of lower pH value (pH is less than or equal to 10) and lower gas-liquid ratio (1500: 1) then, for the coal-fired power plant desulfurization wastewater with ammonia nitrogen concentration less than 1500mg/L, the ammonia nitrogen of the primary stripping deamination water can be reduced to less than or equal to 5mg/L, and the requirement of discharge standard can be metThe spare investment and the operation cost are low.
(2) The economic efficiency is as follows: compared with the traditional ammonia nitrogen direct stripping process, the invention comprises the following steps: 1) the heating facilities do not need to be invested and constructed; the gas consumption is only 25% of that of the traditional ammonia nitrogen direct stripping process, and the fan investment is greatly reduced; 2) the deamination gas is directly reused for flue gas denitration, and deamination recovery and crystallization solidification facilities do not need to be built; 3) the ammonia nitrogen of the water produced by the primary stripping deamination can be reduced to less than or equal to 5mg/L, and the requirement of the discharge standard can be met. The process equipment is simple, the occupied area is small, and the engineering construction investment is low; the construction investment can be reduced by more than 60 percent.
Compared with the traditional ammonia nitrogen direct stripping process, the ammonia nitrogen stripping process can meet the ammonia nitrogen stripping operation requirement under the condition that the pH value is less than or equal to 10, the pH value of the ammonia water to be stripped is generally less than or equal to 9, and the discharge standard can be met without adding acid liquid (such as hydrochloric acid) to adjust the pH value. Greatly reduces the consumption of acid and alkali, and although the blowing-off auxiliary agent needs to be added according to 10-20mg/L, the cost of the blowing-off auxiliary agent for treating per ton of water is only 0.2-0.4 yuan, but the total cost of the medicine can be reduced by about 20%.
Compared with the traditional ammonia nitrogen direct stripping process, the process disclosed by the invention has the advantages that 1) the desulfurization wastewater is fully utilized, the liquor drainage temperature is generally 50-55 ℃, the preposed process equipment adopts proper heat preservation measures, the softened water production temperature can reach 35-40 ℃, the requirement of ammonia nitrogen stripping on the operation temperature can be met, and heating heat energy is not required to be consumed; 2) the operation gas-liquid ratio of the invention is 1500:1, the gas consumption is only 25% of the traditional ammonia nitrogen direct stripping process, and the energy consumption of the fan is greatly reduced; 3) the deamination gas is directly reused for flue gas denitration, and deamination recovery and crystallization solidification facilities do not need to be built, so that the operation energy consumption of equipment is further reduced; 4) for the desulfurization wastewater of the coal-fired power plant with the ammonia nitrogen concentration less than 1500mg/L, the one-stage stripping deamination water production can meet the requirement of the discharge standard without multi-stage stripping, thereby further reducing the energy consumption of equipment operation. In general, the energy consumption of the system is about 25 percent of that of the traditional ammonia nitrogen direct stripping process system.
(3) Environmental benefits: in order to control NOx of discharged flue gas, a flue gas denitration process is generally implemented in coal-fired power plants in China, ammonia nitrogen in flue gas desulfurization wastewater exceeds the standard due to ammonia escape, some power plant desulfurization wastewater belongs to low-concentration ammonia nitrogen wastewater (ammonia nitrogen is less than or equal to 50mg/l), and chemical flocculation clarification produced water can meet the requirements of discharge standards by scientifically and reasonably selecting a flocculating agent; some power plant desulfurization waste water belongs to medium-concentration ammonia nitrogen waste water (ammonia nitrogen: 50-500 mg/l); a few power plant desulfurization waste water belongs to high-concentration ammonia nitrogen waste water (ammonia nitrogen is more than 500 mg/l). However, the components of the desulfurization wastewater are complex and variable, and the desulfurization wastewater has the characteristics of high salt content, high turbidity, high hardness, heavy metal, fluoride, sulfide, silicon, organic matter and the like, so that the application of various ammonia nitrogen removal processes is limited by different degrees, and the standard discharge of the wastewater of a coal-fired power plant is restricted.
According to the invention, by adopting the high-surface-area packed tower and the ammonia nitrogen auxiliary agent stripping technology, the ammonia nitrogen concentration of the primary stripping deamination water is less than or equal to 5mg/L under the conditions of lower pH value (pH is less than or equal to 10) and lower gas-liquid ratio (1500: 1), the desulfurization wastewater of the coal-fired power plant with the ammonia nitrogen concentration of less than 1500mg/L meets related discharge standards, and the method has obvious environmental benefits, social benefits and economic benefits for solving the ammonia nitrogen exceeding dilemma caused by the standard-reaching discharge of the wastewater.
In order to verify the ammonia nitrogen stripping effect of the desulfurization wastewater treatment system provided by the invention, the invention is verified by specific embodiments, which are specifically as follows:
A. the pretreatment adopts a patent 201721234076.6, which is described in detail in the patent, and the inflow rate is 5m3H is used as the reference value. The index of the water quality of the pretreatment is shown in Table 4, the water content of the sludge is shown in Table 5, and the toxic leaching of the mud cake is shown in Table 6. (because the liquid discharge temperature of the desulfurization wastewater is 51.7 ℃, the temperature of the water produced by the softening unit is 35-40 ℃, and necessary heat preservation measures are adopted when the pretreatment unit is designed)
TABLE 4 quality index of the incoming water
TABLE 5 mud cake moisture content
| Mud cake moisture content (%) | Standard requirements | Conclusion |
| 36.13 | ≤60％ | Qualified |
Note: sludge for sludge disposal and mixed landfill in urban sewage treatment plants (GB/T23485-2009) requires that when sludge is used for mixed landfill, the water content is not higher than 60%, and when the sludge is used as a covering soil additive of a refuse landfill, the water content of the sludge is not higher than 45%.
TABLE 6 toxic Leaching of dewatered sludge cake from flocculated sludges of desulfurized waste waters
| Index (I) | Arsenic (As) | Copper (Cu) | Zinc | Lead (II) | Cadmium (Cd) |
| Unit of | mg/L | mg/L | mg/L | mg/L | mg/L |
| Limit value | 5 | 100 | 100 | 5 | 1 |
| Measured value | 0.13*10-3 | 2.42*10-3 | ND | 2.61*10-3 | ND |
| Index (I) | Chromium (III) | Beryllium (beryllium) | Barium salt | Nickel (II) | Mercury |
| Unit of | mg/L | mg/L | mg/L | mg/L | mg/L |
| Limit value | 15 | 0.02 | 100 | 5 | 0.1 |
| Measured value | ND | ND | 32.96*10-3 | 32.96*10-3 | 1.23*10-3 |
B. The pretreated produced water overflows to a softening unit, and the softening unit adopts the traditional lime-sodium carbonate softening technology to reduce scale ions such as calcium, magnesium and the like in the desulfurization wastewater. The softening unit is a two-stage reaction precipitation and clarification process, calcium hydroxide is added into a first-stage reactor to adjust the pH value of the wastewater, so that part of heavy metal ions and Mg in the desulfurization wastewater2+And silicon and other pollutants and part of scale-causing ions generate precipitates; sodium carbonate is added into the secondary reactor to ensure that Ca in the wastewater is2+Forming calcium carbonate precipitate and removing Ca in the wastewater2+Finally, solid-liquid separation is carried out through the sedimentation clarification tank, sludge is separately treated, and finally the softening pretreatment effect of the desulfurization wastewater is realized. The chemical softening slurry and the pretreatment flocculation slurry are mixed and pumped to a dehydrator for dehydration (shared by a pretreatment unit), the filtrate of the dehydrator is returned to a wastewater inlet of the one-step efficient flocculation device for circular treatment, and the mud cake generated by the dehydrator is treated as solid waste.
The equipment for storing and adding the medicament, the reactor, the clarifier, the pump, the valve, the pipeline and the like in the system are conventional equipment of the desulfurization wastewater treatment system and have the treatment capacity of 5m according to the system3And (5) selecting and designing the/h requirement and the related engineering specification.
In view of the fact that the liquid discharge temperature of the desulfurization wastewater is 51.7 ℃, necessary heat preservation measures are taken when the softening unit is designed to ensure that the temperature of water produced by the softening unit is 35-40 ℃.
C. Pretreating, softening and treating raw water of the desulfurization wastewater, and adjusting the pH value of softened produced water to 10; pumping softened water to a softened water production tank, adding a blow-off auxiliary agent according to 15mg/L, and fully and uniformly mixing;
the blowing-off auxiliary agent added comprises 25% of octadecyl trimethoxy silane, 25% of fluorocarbon surfactant, 20% of cyclohexanone, 20% of cyclopentane and 10% of hydroxymethyl fiber sodium salt.
In view of the fact that the liquid discharge temperature of the desulfurization wastewater is 51.7 ℃, appropriate heat preservation measures are adopted through preposed process equipment, the temperature of softened produced water is 36.8 ℃, the requirement of ammonia nitrogen stripping on the operation temperature can be met, and heating facilities do not need to be arranged. Ammonia nitrogen wastewater is atomized and sprayed from the tower top, ambient air is blown from the tower bottom, ammonia nitrogen stripping is carried out in the tower, ammonia-containing air is discharged from the tower top and is sent to a hearth along with secondary air for denitration, and deamination water is discharged from the tower bottom. The invention can blow off ammonia nitrogen once until the ammonia nitrogen reaches the standard and is discharged.
The ammonia nitrogen blows and takes off the tower, and the packed bed adopts four sections packing layers, and each layer volume is the same, and from bottom to top, the first layer adopts high-efficient plastics random packing, size: 83x95 mm; effective specific surface area: 240m2/m3(ii) a Number of units volume: 1020/m3(ii) a Porosity: 92 percent; weight: 105kg/m polypropylene material3(ii) a Number of liquid drops that can be created: 770000 pieces/m3(ii) a The second, third and fourth layers adopt pulse structured packing, and the specifications are shown in Table 7:
TABLE 7 Filler specification
| Type of filler | Specific surface area m2/m3 | |
| Second layer of structured packing | TJH355 | 355 |
| Third layer of regular packing | TJH555 | 555 |
| The fourth layer of regular packing | TJH755 | 755 |
The demister is composed of three-stage ridge demisters, the first-stage ridge demister has the module blade interval of 28 mm; the pitch of the module blades of the second-stage ridge type demister is 23 mm; and a third-stage ridge type demister, wherein the module blade interval is 21 mm.
Main operation parameters of the deamination tower;
the inlet air temperature of the tower body is as follows: normal temperature;
tower body air inlet flow rate: 20m/s
The liquid inlet temperature of the tower body is as follows: 36.8 ℃;
gas-liquid ratio: 1500: 1;
cyclone flow state flow velocity: 3 m/s;
tower exhaust flow rate: 20 m/s;
operating pressure: normal pressure;
water distribution atomized droplet particle size: 100-;
water quality of inlet water: TSS is 9 mg/L; the supersaturation index SI of the calcium sulfate is 2.96; the oil content is 4.2 mg/L; the silicon content is 16.8 mg/L; the ammonia nitrogen content is 669.6 mg/L.
The ammonia nitrogen in the obtained deamination water is 3.24mg/L, the test result of ammonia nitrogen auxiliary agent stripping is shown in Table 8, and the ammonia nitrogen stripping test in Table 8
According to the experimental data in Table 8, the invention is proved to adopt two process technologies of a high-surface-area packed tower and an ammonia nitrogen high-efficiency blowing-off auxiliary agent, and NH is greatly reduced by changing the occurrence form of ammonia nitrogen in the desulfurization wastewater3Binding force with water molecules and strengthening NH3Mass transfer rate from liquid to gas phase. The pH value is 10, the gas-liquid ratio is 1500:1, under the condition that the wastewater is not heated, for the desulfurization wastewater of a coal-fired power plant with the ammonia nitrogen concentration of 669.6mg/L, the ammonia nitrogen in the primary stripping deamination water can be reduced to 3.24mg/L, the pH value of the deamination water is 8.89, and acid liquor (such as hydrochloric acid) is not required to be added to adjust the pH value, so that the discharge standard can be met.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The utility model provides a have desulfurization effluent disposal system that ammonia nitrogen blows and takes off function which characterized in that: comprises a pretreatment unit, a softening unit and an ammonia nitrogen stripping unit which are connected in sequence;
the pretreatment unit is used for pretreating desulfurization wastewater;
the softening unit is used for carrying out scale-causing ion reduction treatment on the pretreated desulfurization wastewater;
the ammonia nitrogen stripping unit is used for carrying out ammonia nitrogen stripping treatment on the softened desulfurization wastewater;
the ammonia nitrogen stripping unit comprises a softening product water tank, an ammonia nitrogen stripping tower, a waste gas collecting device and a deamination product water tank; the softening unit is connected with a water inlet of the softening water production tank; the water outlet of the softening water production tank is connected with the water inlet of the ammonia nitrogen stripping tower; the softening water production tank is provided with a blowing-off auxiliary agent feeding hole; the exhaust port of the ammonia nitrogen stripping tower is connected with the waste gas collecting device; and the water outlet of the ammonia nitrogen stripping tower is connected with the ammonia nitrogen production water tank.
2. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 1, characterized in that: a demisting mechanism, an atomizing spray head, a packed bed and a gas generating mechanism are sequentially arranged in the ammonia nitrogen stripping tower from top to bottom; the exhaust port of the ammonia nitrogen stripping tower is positioned at the top; the water outlet of the ammonia nitrogen stripping tower is positioned at the bottom; the atomization spray header is connected with a water outlet of the softening water production tank.
3. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 2, characterized in that: the gas generating mechanism comprises a gas inlet, a guide plate and a gas inlet distribution modulator; the baffle is disposed between the gas inlet and the inlet gas distribution modulator; the air entering from the air inlet is guided by the guide plate to flow to the air inlet distribution modulator, and the air inlet distribution modulator is used for adjusting the air to be in a cyclone flow state and rising;
the air inlet is connected with an air filter; the air filter is connected with the fan;
the upper part and the lower part of the gas inlet distribution modulator are hemispherical, the middle section is an isometric cylindrical hollow pipe, and the middle section is sleeved with an impeller.
4. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 2, characterized in that: the packed bed consists of a plurality of packing layers; from bottom to top, the specific surface area of unit volume of the filler is increased by 1.25 to 2.5 times layer by layer;
the filler of the packed bed is made of corrosion-resistant and anti-fouling plastic materials.
5. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 4, characterized in that: the packed bed is divided into two parts, wherein the upper part adopts regular packing, and the lower part adopts bulk packing.
6. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 2, characterized in that: the demisting structure comprises a three-stage ridge type demister, a washing device and a washing control system;
the flushing control system comprises a differential pressure sensor, a differential pressure transmitter and a control circuit board; the upper side and the lower side of each ridge type demister are respectively provided with the differential pressure sensor; two adjacent differential pressure sensors are connected with the same differential pressure transmitter; the pressure difference transmitter is electrically connected with the control circuit board.
7. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 6, characterized in that: each stage of ridge type demister is formed by combining a plurality of demister blades; the demister blades are provided with water collecting barbs; liquid collecting grooves are formed in the bottoms of the ridge type demisters at all levels; each liquid collecting groove is connected with the same liquid collecting pipeline; and the liquid collecting pipeline is connected with the bottom of the ammonia nitrogen stripping tower.
8. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 2, characterized in that: an exhaust gas distribution modulator is arranged at an exhaust port of the ammonia nitrogen stripping tower; the lower part of the exhaust gas distribution modulator is hemispherical, and the upper part and the middle part are cylindrical hollow pipes with the same diameter; the middle section of the exhaust gas distribution modulator is sleeved with an impeller; and a plurality of airflow guide blades are arranged at an exhaust port of the ammonia nitrogen stripping tower.
9. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 1, characterized in that: the ammonia nitrogen stripping unit also comprises a stripping auxiliary agent storage tank; and the blow-off additive storage box is connected with a blow-off additive feeding hole of the softening water production tank.
10. The desulfurization wastewater treatment system with ammonia nitrogen stripping function as claimed in claim 9, characterized in that: the ammonia nitrogen stripping auxiliary agent storage tank stores the ammonia nitrogen stripping auxiliary agent;
the ammonia nitrogen stripping auxiliary agent comprises, by weight, 15% -35% of octadecyl trimethoxy silane, 15% -35% of fluorocarbon surfactant, 10% -30% of cyclohexanone, 10% -30% of cyclopentane and 10% -15% of hydroxymethyl fiber sodium salt; the octadecyl trimethoxy silane and the fluorocarbon surfactant are compounded according to the ratio of 1: 1.
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| CN113461091A (en) * | 2021-07-13 | 2021-10-01 | 福泉环保城发展有限公司 | Spiral ammonia nitrogen blows and takes off device |
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