CN111453915A - Wastewater concentration system based on air humidification and dehumidification and concentration method thereof - Google Patents
Wastewater concentration system based on air humidification and dehumidification and concentration method thereof Download PDFInfo
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- CN111453915A CN111453915A CN202010420964.7A CN202010420964A CN111453915A CN 111453915 A CN111453915 A CN 111453915A CN 202010420964 A CN202010420964 A CN 202010420964A CN 111453915 A CN111453915 A CN 111453915A
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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
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/048—Purification of waste water by evaporation
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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
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/10—Treatment of water, waste water, or sewage by heating by distillation or evaporation by direct contact with a particulate solid or with a fluid, as a heat transfer medium
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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
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/002—Construction details of the apparatus
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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
- C02F2301/00—General aspects of water treatment
- C02F2301/04—Flow arrangements
- C02F2301/046—Recirculation with an external loop
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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
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Abstract
The invention relates to a wastewater concentration system based on air humidification and dehumidification.A humidification tower is provided with a water distributor, a packing bed layer and a tower bottom air distribution disc, one end of a concentrated solution circulation pipeline is communicated with the water distributor, the other end of the concentrated solution circulation pipeline is communicated with a cold side heat exchange port B, and a concentrated solution lift pump, a heat main heat exchanger and a first auxiliary heat exchanger are sequentially connected to the concentrated solution circulation pipeline; the dehumidification tower is provided with a dehumidification air outlet E, a water distributor and a packing bed layer, one end of a clear liquid circulation pipeline is connected and communicated with the water distributor, the other end of the clear liquid circulation pipeline is connected and communicated with a hot-side heat exchange port D, a clear liquid lifting pump, a main heat exchanger and a second auxiliary heat exchanger are sequentially connected to the clear liquid circulation pipeline, one end of an inter-tower pipeline is connected and communicated with the humidification tower, the other end of the inter-tower pipeline is connected and communicated with the dehumidification tower, one end of the air circulation pipeline is connected and communicated with the dehumidification air outlet E of the dehumidification tower, and the other end of the. The invention has the advantages of low energy consumption, low treatment cost and capability of improving the concentration efficiency of the wastewater.
Description
Technical Field
The invention relates to a wastewater concentration system based on air humidification and dehumidification and a concentration method thereof, belongs to the field of wastewater concentration treatment, and particularly relates to harmless treatment of percolate membrane concentrated solution.
Background
The currently widely used method for treating leachate is a Membrane Bioreactor (MBR) method, and the leachate after biochemical treatment enters a nanofiltration/reverse osmosis membrane integrated device for advanced treatment, and the treatment method can produce 10-30% of membrane concentrated solution. At present, the methods for treating the membrane concentrated solution are not many, and the typical process is an evaporation process, which mainly comprises an immersion combustion treatment technology (SCE) and a vapor recompression evaporation treatment technology (MVR/MVC): the SCE treatment technology is that high-temperature flue gas generated by burning methane and air is directly sprayed into concentrated solution and is heated and evaporated in a direct contact heat transfer mode. The MVR/MVC processing technology is an energy-saving technology which utilizes secondary steam generated by an evaporation system and energy thereof to compress and apply work through a steam compressor and improve heat energy of the secondary steam, and the heat is circularly supplied to a concentrated solution evaporation system, so that the requirement on external energy can be reduced.
The existing evaporation treatment technology needs the concentrated solution to be in a boiling state, so the concentrated solution needs to be operated under the condition of higher temperature, or the concentrated solution needs to be operated under the condition of reducing the boiling temperature of the concentrated solution under the condition of keeping a certain vacuum degree, so a large amount of energy needs to be consumed, the concentration treatment cost is high, and the application of the prior art is limited. The SCE treatment technology can only be applied to landfill sites with garbage anaerobic fermentation capacity or disposal sites with natural gas supply conditions, and the application is restricted but not popularized. Some concentration systems utilize hot air pressure swing circulation to concentrate wastewater, but the concentration systems need to be provided with a hot compression unit and an expansion unit to carry out air treatment, and the problems of high operation energy consumption, high treatment cost and low concentration treatment efficiency of the systems also exist.
Moreover, because the membrane concentrate often contains extremely high TDS and other pollutants, for example, a large amount of chloride ions contained in the membrane concentrate increase the risk of equipment corrosion under high temperature conditions, and because the membrane concentrate contains high-hardness ions, the scaling problem is particularly serious under the working condition of severe evaporation, and the equipment operation stability is poor.
Disclosure of Invention
The invention aims to provide a waste water concentration system and a waste water concentration method based on air humidification and dehumidification, which have the advantages of low running energy consumption, low treatment cost, stable and reliable system running, no restriction on application and convenience in popularization and application, and can improve the waste water concentration efficiency.
The technical scheme for achieving the aim of the invention is as follows: the utility model provides a concentrated system of waste water based on air is humidified, is dehumidified which characterized in that: comprises a humidifying unit, a dehumidifying unit, a dry and wet air circulating unit and a heat exchange unit;
the humidifying unit is used for concentrating and circulating wastewater and comprises a humidifying tower and a concentrated solution circulating pipeline, a water distributor is arranged at the upper part of the humidifying tower, a tower bottom gas distribution disc is arranged at the lower part of the humidifying tower, a packing bed layer used for increasing the contact area of a liquid phase and a gas phase is arranged between the water distributor and the tower bottom gas distribution disc of the humidifying tower, a wastewater inlet A and a cold side heat exchange port B are sequentially and downwards arranged at the lower part of the tower bottom gas distribution disc of the humidifying tower, one end of the concentrated solution circulating pipeline is communicated with the water distributor in the humidifying tower, and the other end of the concentrated solution circulating pipeline is communicated with the cold;
the dehumidification unit is used for dehumidifying and circulating air and comprises a dehumidification tower and a clear liquid circulation pipeline, wherein a water distributor is arranged at the upper part of the dehumidification tower, a dehumidification air outlet E is arranged at the top part of the dehumidification tower, a packing bed layer used for increasing the contact area of a liquid phase and a gas phase is arranged at the lower part of the water distributor of the dehumidification tower, a clear liquid water inlet C and a hot side heat exchange port D are sequentially and downwards arranged at the lower part of the dehumidification tower, one end of the clear liquid circulation pipeline is communicated with the water distributor in the dehumidification tower, and the other end of the clear liquid circulation pipeline is communicated with the hot side;
the dry and wet air circulation unit is used for closed air circulation of the humidifying tower and the dehumidifying tower and comprises an inter-tower fan and an air circulation pipeline, the inter-tower fan is arranged on the inter-tower pipeline, one end of the inter-tower pipeline is connected and communicated with the humidifying tower, the other end of the inter-tower pipeline is connected and communicated with the dehumidifying tower, one end of the air circulation pipeline is connected and communicated with a dehumidifying air outlet E of the dehumidifying tower, and the other end of the air circulation pipeline is connected and communicated with a tower bottom air distribution disc of the humidifying tower;
the heat exchange unit comprises a main heat exchanger, a first auxiliary heat exchanger and a second auxiliary heat exchanger, a concentrated liquid lifting pump, a heat main heat exchanger and a first auxiliary heat exchanger which are used for heat exchange step by step are sequentially connected to a concentrated liquid circulating pipeline, a clear liquid lifting pump, a main heat exchanger and a second auxiliary heat exchanger which are used for heat exchange step by step are sequentially connected to a clear liquid circulating pipeline, waste water in the concentrated liquid circulating pipeline and clear liquid in the clear liquid circulating pipeline exchange heat once in the main heat exchanger, and a super concentrated liquid discharge pipe is further connected to the front side of the heat main heat exchanger through the concentrated liquid circulating pipeline.
The other technical scheme for achieving the aim of the invention is as follows: a concentration method of a wastewater concentration system based on air humidification and dehumidification is characterized in that: adding wastewater which is pretreated and is free of hardness ions in a water body into the lower part of the tower from a water inlet A of a humidifying tower, enabling the wastewater to enter a concentrated solution circulating pipeline from a cold side heat exchange port A of the humidifying tower, enabling clear solution to enter a clear solution circulating pipeline from a clear solution water inlet C of a dehumidifying tower, and enabling the humidifying tower and the dehumidifying tower to be in a normal pressure state;
starting a concentrated solution lift pump and a clear solution lift pump, wherein the waste water is lifted by the concentrated solution lift pump to be conveyed to a cold side fluid inlet end of a main heat exchanger, the clear solution is lifted by the clear solution to be conveyed to a hot side fluid inlet end of the main heat exchanger, the waste water and the clear solution carry out primary heat exchange in the main heat exchanger, then enter a first auxiliary heat exchanger, carry out secondary heat exchange and then convey into a water distributor at the upper part of a humidifying tower, and the clear solution after primary temperature reduction enters a second auxiliary heat exchanger, is cooled for the second time and then enters the water distributor of the dehumidifying;
the waste water is distributed on a packing bed layer through a water distributor in the humidifying tower and flows towards the tower bottom under the action of gravity, the air dehumidified in the dehumidifying tower is introduced into a tower bottom air distribution disc of the humidifying tower through an air circulation pipeline and flows upwards, mass transfer and heat transfer are carried out on the air and the waste water in the convection mode on the surface of the packing bed layer, moisture in the waste water is carried into the air to obtain damp hot air and concentrated liquid, the obtained concentrated liquid flows to the tower bottom and the waste water entering a system to enter a concentrated liquid circulation pipeline to form waste water concentration circulation, the damp hot air in the humidifying tower is pumped into the dehumidifying tower by an inter-tower fan, clear liquid is distributed on the packing bed layer through the water distributor in the dehumidifying tower and flows towards the tower bottom under the action of gravity, the mass transfer and heat transfer are carried out on the damp hot air and the cooled clear liquid on the surface of the packing bed layer, moisture is separated out when gaseous water vapor in the damp hot air reaches a condensation dew point, water, and the obtained water drops flow to the tower bottom to perform dehumidification circulation on air, and the dehumidified air enters an air circulation pipeline through a dehumidification air outlet E and then enters a tower bottom air distribution disc in the humidifying tower to form dry and wet air circulation.
The invention adopts a humidifying unit, a dehumidifying unit, a dry-wet air circulating unit and a heat exchange unit, wherein the humidifying unit adopts a humidifying tower and a concentrated solution circulating pipeline communicated with the humidifying tower to continuously concentrate and circulate the wastewater, the dehumidifying unit adopts a dehumidifying tower and a clear solution circulating pipeline communicated with the dehumidifying tower to continuously dehumidify and circulate the wet and hot air entering the tower, the humidifying tower and the dehumidifying tower are respectively provided with a filler bed layer for increasing the contact area of a liquid phase and a gas phase, the dehumidified air enters the humidifying tower to perform mass transfer with the wastewater on the surface of the filler bed layer, the moisture in the wastewater is brought into the air to obtain the wet and hot air and the concentrated solution, the wet and hot air is pumped into the filler bed layer of the dehumidifying tower by an inter-tower fan, the mass transfer and heat transfer are performed on the surface of the filler bed layer and the clear solution, so that the water vapor in the wet air reaches the condensation dew point to separate out the moisture and enters the clear, therefore, the heat loss is less, most of heat is transferred into clean clear liquid, and then the heat is exchanged with waste water newly entering the system, so that the running energy consumption is greatly saved. The invention adopts the independent humidifying tower and the dehumidifying tower, does not need to increase the temperature of the liquid phase, can evaporate the liquid under the working condition of normal pressure and the temperature lower than the boiling point, improves the concentration efficiency of the waste water, has stable and reliable system operation, is not restricted in application and is convenient to popularize and apply. The dry and wet air circulation unit adopts the inter-tower fan and the air circulation pipeline, so that the humidifying tower and the dehumidifying tower form closed dry and wet air circulation, and only the inter-tower fan is adopted to continuously pump wet and hot air into the dehumidifying tower, so that a thermal compression unit and an expansion unit are not needed, the operation energy consumption is low, and the treatment cost is effectively reduced. The heat exchange unit adopts the main heat exchanger, the first auxiliary heat exchanger and the second auxiliary heat exchanger, the wastewater in the concentrated solution circulating pipeline and the clear solution in the clear solution circulating pipeline carry out primary heat exchange in the main heat exchanger, the energy required by the wastewater during heating is saved while the temperature of the wastewater is increased, the subsequent cooling step is quicker while the temperature of the clear solution is reduced, the consumption of cooling water is saved, and the evaporation efficiency of the system can be improved. The wastewater subjected to primary heat exchange enters the auxiliary heat exchanger to carry out secondary heat exchange by using industrial waste/waste heat as a heat source, so that the temperature required by the system is reached, and the operation energy consumption of the system is further reduced. The system and the concentration method of the invention have compact and reasonable structure, low energy consumption in operation and capability of reducing the treatment cost.
Drawings
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
FIG. 1 is a schematic structural diagram of a wastewater concentration system based on air humidification and dehumidification according to the present invention.
FIG. 2 is a schematic structural view of the water distributor of the present invention.
FIG. 3 is a schematic view of the porous water distribution loop structure of the water distributor of the present invention.
FIG. 4 is a schematic structural diagram of a first-stage sieve pore water distribution plate of the water distributor of the present invention.
FIG. 5 is a schematic diagram of a secondary mesh water distribution plate of the water distributor of the present invention.
Wherein: 1-a humidifying tower, 2-a water distributor, 2-1-a porous water distribution ring pipe, 2-11-a spray header, 2-12-a pipe ring, 2-13-an intermediate communicating pipe, 2-a first-stage sieve pore water distribution plate, 2-3-a second-stage sieve pore water distribution plate, 3-an air circulation pipeline, 4-a concentrated liquid circulation pipeline, 5-a clear liquid circulation pipeline, 6-an inter-tower pipeline, 7-an inter-tower fan, 8-a dehumidifying tower, 9-a packing bed layer, 10-an air distribution disc, 11-a tower bottom air distribution disc, 12-a pretreatment unit, 13-a cooling water tower, 14-a filter, 15-a concentrated liquid lifting pump, 16-a concentrated liquid discharge pipe row, 17-a second auxiliary heat exchanger, 18-a dryer, 19-a main heat exchanger, 20-a clear liquid lifting pump and 21-a first auxiliary heat exchanger.
Detailed Description
As shown in fig. 1, the wastewater concentration system based on air humidification and dehumidification of the invention comprises a humidification unit, a dehumidification unit, a dry and wet air circulation unit and a heat exchange unit.
As shown in figure 1, the humidifying unit of the invention is used for concentrating and circulating wastewater, and comprises a humidifying tower 1 and a concentrated solution circulating pipeline 4, wherein the concentrated solution circulating pipeline 4 can adopt economic and widely available pipe fittings made of polymer materials, and can prevent the wastewater, particularly concentrated solution, from corroding system pipelines. As shown in figure 1, the humidifying tower 1 of the invention is provided with a water distributor 2 at the upper part and a tower bottom gas distribution disc 11 at the lower part, water can be uniformly distributed on a packing bed layer 9 in the humidifying tower 1 through the water distributor 2, the tower bottom gas distribution disc 11 can introduce dehumidified air into the lower part in the humidifying tower 1, the humidifying tower 1 is provided with the packing bed layer 9 for increasing the contact area of liquid phase and gas phase between the water distributor 2 and the tower bottom gas distribution disc 11, the packing bed layer 9 is a single layer or multiple layers arranged at intervals, the packing bed layer 9 is filled with a plurality of pall ring packings, or a plurality of Raschig ring packings, or a plurality of saddle ring packings, the contact area of the wastewater and the flowing air is increased through the packing bed layer 9 filled with a large amount of light structured packings, so as to carry out sufficient mass and heat transfer, and bring the moisture in the wastewater into the. As shown in fig. 1, a wastewater inlet a and a cold-side heat exchange port B are sequentially and downwardly arranged at the lower part of a tower bottom gas distribution plate 11 of the humidifying tower 1, the cold-side heat exchange port B can be arranged at the bottom of the humidifying tower 1, one end of a concentrated solution circulation pipeline 4 is communicated with a water distributor 2 in the humidifying tower 1, and the other end is communicated with the cold-side heat exchange port B, so that wastewater entering the humidifying tower 1 can be continuously concentrated and flows into the bottom of the humidifying tower for circulation.
As shown in figure 1, a wastewater inlet A of a humidifying tower 1 is communicated with a wastewater inlet pipe, the wastewater inlet pipe is communicated with a water outlet of a pretreatment unit 12, the pretreatment unit 12 is used for removing hardness ions in wastewater and preheating the wastewater, calcium and magnesium hardness ions in a water body can be removed by adopting the conventional methods of adjusting the pH value, increasing charges or electromagnetism and the like, particularly for a membrane concentrated solution, the degradation of the calcium and magnesium hardness ions to a treatment system under the high-temperature condition can be better reduced, the wastewater is preheated in the pretreatment stage, the temperature of the wastewater entering the humidifying tower 1 is 30-40 ℃, and the heat requirement of the concentration system is reduced.
As shown in figure 1, the dehumidification unit is used for dehumidifying and circulating air and comprises a dehumidification tower 8 and a clear liquid circulating pipeline 5, the clear liquid circulating pipeline 5 can adopt a common carbon steel material and is additionally provided with a spraying layer, and the spraying layer is a high-molecular organic coating which is resistant to chemical corrosion, strong in thermal stability and strong in functional group stability, so that the manufacturing cost of the material can be greatly reduced. As shown in figure 1, the upper part of a dehumidification tower 8 of the invention is provided with a water distributor 2, the top part of the dehumidification tower 8 is provided with a dehumidification air outlet E, the lower part of the water distributor 2 of the dehumidification tower 8 is provided with a packing bed layer 9 for increasing the contact area of a liquid phase and a gas phase, the packing bed layer 9 in the dehumidification tower 8 is a single layer or a plurality of layers arranged at intervals, the packing bed layer 9 is filled with a plurality of pall ring packing, Raschig ring packing or saddle ring packing, the contact area of clear liquid and flowing hot humid air is increased by filling a large amount of light structured packing to carry out sufficient mass and heat transfer, when the hot humid air reaches a saturated dew point, gaseous water vapor in the air is condensed into liquid small water drops, the gradually increased water drops flow from the top layer of the tower body to the bottom layer and are gathered at the bottom layer due to gravity, the dehumidified air rises to the top of the tower body to carry out dehumidification circulation on the air, and the dry air is then conveyed into a gas distribution disc 11 at the Circulation, therefore the liquid evaporation of the invention can be carried out under normal pressure working condition and at the temperature lower than boiling point, and most of heat is transferred to clean clear liquid and then exchanges heat with waste water newly entering the system, thereby having less heat loss and saving operation energy consumption. As shown in fig. 1, a clear liquid water inlet C and a hot side heat exchange port D are sequentially and downwardly arranged at the lower part of the dehumidification tower 8, clear liquid is added into the lower part of the dehumidification tower 8 through the clear liquid water inlet C to meet the system operation requirement, the hot side heat exchange port D can be arranged at the bottom of the dehumidification tower 8, one end of a clear liquid circulation pipeline 5 is communicated with a water distributor 2 in the dehumidification tower 8, the other end of the clear liquid circulation pipeline is communicated with the hot side heat exchange port D, and the hot and humid air of the dehumidification tower 8 is continuously dehumidified.
As shown in figures 1 and 2, the water distributor 2 comprises a porous water distribution ring pipe 2-1 and a first-stage sieve pore water distribution plate 2-2 positioned at the lower part of the porous water distribution ring pipe 2-1, a plurality of spray heads 2-11 are uniformly distributed on the porous water distribution ring pipe 2-1, and the number of water outlets on the first-stage sieve pore water distribution plate 2-2 is larger than that of the spray heads 2-11 on the porous water distribution ring pipe 2-1 Rapid water distribution, strong anti-scaling property and the like. As shown in figures 2 and 3, the porous water distribution ring 2-1 of the invention comprises at least more than two pipe rings 2-12 with different sizes and an intermediate communicating pipe 2-13, 2-12 circular or rectangular pipe rings can be adopted, 3-5 rings can be arranged on the 2-12 pipe rings, the distance between the rings is 150-210 mm, the pipe rings 2-12 are communicated with each other by at least two intermediate communicating pipes 2-13, and the pipe section extending outwards of the intermediate communicating pipe 2-13 is arranged at the interface, the diameter of the water outlet hole on the first-stage sieve pore water distribution plate 2-2 is less than or equal to the diameter of the water outlet hole of the spray header 2-11, water outlets which can be symmetrically distributed along the axis of the pipe rings 2-12, for example, 4-16 water outlets are arranged on each pipe ring 2-12, and the water outlet caliber of the spray header 2-11 is 25-30 mm, and the water flows out to the lower-layer first-stage sieve pore water distribution plate 2-2 for primary water distribution. The primary sieve pore water distribution plate 2-2 can adopt matrix type distribution holes, the aperture is 20-25 mm, the hole pitch is 80-90 mm, and the primary sieve pore water distribution plate can be adjusted according to the size of a tower body. As shown in figures 2-4, the water distributor 2 of the invention also comprises a second-level sieve pore water distribution plate 2-3 positioned at the lower part of the first-level sieve pore water distribution plate 2-2, the first-level sieve pore water distribution plate 2-2 and the second-level sieve pore water distribution plate 2-3 can be detachably arranged on the tower, the aperture of the water outlet hole on the second-level sieve pore water distribution plate 2-3 is smaller than that of the water outlet hole on the first-level sieve pore water distribution plate 2-2, the water outlet hole on the second-level sieve pore water distribution plate 2-3 is staggered with the water outlet hole on the first-level sieve pore water distribution plate 2-2, the second-level sieve pore water distribution plate 2-3 can adopt matrix type distribution holes with the aperture of 10-15 mm and the hole pitch of 80-90 mm, the fluid after water distribution falls onto the second-level sieve pore water distribution plate 2-3, the flow velocity of the fluid after the secondary water distribution is slower, the flow is thinner and the distribution is more uniform, thereby being beneficial to carrying out sufficient mass and heat transfer with the air.
As shown in fig. 1, the dry and wet air circulation unit of the present invention is used for closed air circulation of a humidifying tower 1 and a dehumidifying tower 8, and includes an inter-tower fan 7 and an air circulation pipeline 3, the inter-tower fan 7 is installed on the inter-tower pipeline 6, one end of the inter-tower pipeline 6 is connected and communicated with the humidifying tower 1, the other end is connected and communicated with the dehumidifying tower 8, one inter-tower fan 7 or a plurality of inter-tower fans 7 can be adopted, an air distribution plate 10 is provided in the dehumidifying tower 8, the other end of the inter-tower pipeline 6 can be connected to the air distribution plate 10, and wet and hot air is continuously pumped into the dehumidifying tower 8 through the inter-tower fan 7. As shown in fig. 1, one end of the air circulation pipeline 3 of the present invention is connected and communicated with the dehumidified air outlet E of the dehumidification tower 8, and the other end is connected and communicated with the tower bottom air distribution plate 11, and the dry air dehumidified by the dehumidification tower 8 is introduced into the humidification tower 1 through the tower bottom air distribution plate 11 to perform air circulation. The tower bottom gas distribution plate 11 of the invention can adopt the existing gas distribution plate, and the dehumidified air is uniformly distributed in the humidifying tower 1 through the tower bottom gas distribution plate 11.
As shown in figure 1, the inter-tower pipeline 6 of the invention is connected with a plurality of branch pipes which are connected in parallel at the rear part of an inter-tower fan 7, the dehumidification tower 8 is also provided with an air distribution disc 10 at the lower part of the corresponding packing bed layer 9, the air distribution disc 10 adopts the existing air distribution disc, the plurality of branch pipes are communicated with the respective corresponding air distribution discs 10, the damp and hot air is uniformly distributed in the dehumidification tower 8 through the air distribution disc, the damp and hot air can be continuously pumped into the dehumidification tower 8 by using the inter-tower fan 7, and the mass transfer and heat transfer are carried out between the clear liquid and the clear liquid in each packing bed layer 9, so that the contact area between the clear liquid and the damp and hot air is further increased, and the evaporation. The invention has a plurality of inter-tower pipelines 6, 3-10 inter-tower pipelines 6 can be adopted, each inter-tower pipeline 6 is provided with a corresponding inter-tower fan 7, the dehumidification tower 8 is also provided with an air distribution disc 10 at the lower part of each corresponding packing bed layer 9, one end of each inter-tower pipeline 6 is connected to the humidification tower at intervals, the other end is communicated with each corresponding air distribution disc 10, the wet and hot air is continuously pumped into the dehumidification tower 8 by the inter-tower fans 7, and the heat and the mass transfer with the clear liquid are carried out in each packing bed layer 9, so that the evaporation efficiency is improved.
As shown in figure 1, the humidifying tower 1, the dehumidifying tower 8, the concentrated solution circulating pipeline 4, the clear solution circulating pipeline 5, the air circulating pipeline 3 and the inter-tower pipeline 6 are externally coated with heat-insulating layers, and external heat-insulating cotton materials are additionally coated on the water pipeline and the tower body of the whole system, so that the heat loss of the system can be further reduced, and the operation energy consumption is saved.
As shown in fig. 1, the heat exchange unit of the present invention includes a main heat exchanger 19, a first auxiliary heat exchanger 21 and a second auxiliary heat exchanger 17, and the main heat exchanger 19, the first auxiliary heat exchanger 21 and the second auxiliary heat exchanger 17 may be plate heat exchangers made of high-efficiency anticorrosive materials, which has advantages of small floor area, large heat exchange area, high heat exchange efficiency, easy disassembly and cleaning, etc. compared with the conventional shell-and-tube heat exchanger. As shown in fig. 1, a concentrated solution lift pump 15, a main heat exchanger 19 for stepwise heat exchange, and a first auxiliary heat exchanger 21 are sequentially connected to a concentrated solution circulation pipeline 4, a clear solution lift pump 20, a main heat exchanger 19 for stepwise heat exchange, and a second auxiliary heat exchanger 17 are sequentially connected to a clear solution circulation pipeline 5, a filter 14 can be connected to the concentrated solution circulation pipeline 4 on the front side of the liquid inlet of the concentrated solution lift pump 15, and similarly, a filter 14 is connected to the clear solution circulation pipeline 5 on the front side of the liquid inlet of the clear solution lift pump 20, the waste water and the clear solution are filtered through the respective filters 14, the waste water in the concentrated solution circulation pipeline 4 and the clear solution in the clear solution circulation pipeline 5 exchange heat in the main heat exchanger 19, and the energy required by the waste water during heating is saved while the temperature of the waste water is increased; for the clear liquid, the temperature is reduced, meanwhile, the subsequent cooling step is quicker, the consumption of cooling water is saved, and the concentration treatment efficiency of the system is improved. The first auxiliary heat exchanger 21 is communicated with the industrial waste/waste heat, the waste water after primary heat exchange enters the first auxiliary heat exchanger 21 to carry out secondary heat exchange with a heat source, and the temperature required by the system is reached. The second auxiliary heat exchanger 17 of the invention is communicated with the condensed water of the cooling water tower 13, the clear liquid after the primary heat exchange and temperature reduction enters the second auxiliary heat exchanger 17 to carry out the secondary heat exchange and temperature reduction with the condensed water, the temperature after the temperature reduction reaches the temperature required by the system operation of 30 ℃ to 40 ℃, and then the clear liquid is uniformly distributed into the filler bed layer 9 of the tower body through the water distributor 2 of the dehumidification tower 8.
As shown in fig. 1, the concentrated solution circulation pipeline 4 of the present invention is further connected with a super concentrated solution discharge pipe 16 at the front side of the main heat exchanger 19, the super concentrated solution is connected with a dryer 18, the super concentrated solution collected at the bottom of the humidifying tower 1 is discharged to the dryer 18 through a concentrated solution lift pump 15 for secondary concentration and drying, and the salt mud formed after drying is filled into a ton bag with an inner container for backfill treatment.
The pretreatment unit 12, the humidifying tower 1, the dehumidifying tower 8, the inter-tower fan 7, the main heat exchanger 19, the first auxiliary heat exchanger 21, the second auxiliary heat exchanger 17, the cooling water tower 13, the drying machine 18 and valves on all pipelines can realize automatic starting, running and stopping of the wastewater concentration system through a P L C automatic control system, and manual operation can be greatly and effectively reduced.
As shown in figure 1, the concentration method of the wastewater concentration system based on air humidification and dehumidification of the invention comprises the steps of adding wastewater which is pretreated and is free of hardness ions in a water body into the lower part of the tower from a water inlet A of a humidification tower 1, wherein the wastewater can be leachate or leachate membrane concentrate and the like, the temperature of the wastewater in the humidification tower 1 is 30-40 ℃, the wastewater enters a concentrated solution circulation pipeline 4 from a cold side heat exchange port A of the humidification tower 1, clear solution is added into the lower part of the tower from a clear solution water inlet C of a dehumidification tower 8 and enters a clear solution circulation pipeline 5, the temperature of the clear solution is 85-95 ℃, and the humidification tower 1 and the dehumidification tower 8 are in a normal pressure state.
As shown in figure 1, the invention starts a concentrated solution lift pump 15 and a clear solution lift pump 20, wastewater is sent to a cold side fluid inlet end of a main heat exchanger 19 by the concentrated solution lift pump 15, clear solution is sent to a hot side fluid inlet end of the main heat exchanger 19 by the clear solution lift pump 20, the wastewater and the clear solution carry out primary heat exchange in the main heat exchanger 19, the wastewater at 30-40 ℃ and high temperature clear solution at 85-95 ℃ carry out primary heat exchange, the temperature of the wastewater after heat exchange by the main heat exchanger 19 can reach 65-85 ℃, then the wastewater enters a first auxiliary heat exchanger 21, after secondary heat exchange, the wastewater is sent to a water distributor 2 at the upper part of a humidifying tower 1, the wastewater after heat exchange by the main heat exchanger 19 enters the first auxiliary heat exchanger 21 to carry out secondary heat exchange and temperature rise with industrial waste heat/waste heat, the temperature required by system operation reaches 85-95 ℃, and the wastewater reaching the temperature is sent to, then the water is uniformly distributed to a packing bed layer 9 of the tower body through a water distributor 2. The temperature of the clear liquid after heat exchange and temperature reduction by the main heat exchanger 19 can reach 55-65 ℃, the clear liquid after primary temperature reduction enters the second auxiliary heat exchanger 17, after secondary cooling, the clear liquid enters the water distributor 2 of the dehumidification tower 8, the clear liquid after primary heat exchange and temperature reduction enters the second auxiliary heat exchanger 17 to carry out secondary heat exchange and temperature reduction with the condensed water, the temperature required by system operation is 30-40 ℃, then the clear liquid is uniformly distributed into the filler bed layer 9 through the water distributor 2 at the top of the tower, the temperature of part of the clear liquid reaches the allowable discharge range, and the clear liquid is discharged.
As shown in figure 1, the waste water in the invention is distributed on a packing bed layer 9 through a water distributor 2 in a humidifying tower 1 and flows towards the bottom of the tower under the action of gravity, the air dehumidified in a dehumidifying tower 8 is introduced into a tower bottom air distribution disc 11 of the humidifying tower 1 through an air circulation pipeline 3 and flows upwards, the air and the waste water carry out mass transfer and heat transfer in a convection manner on the surface of the packing bed layer 9, the contact area of the waste water and the flowing air is enlarged through a large amount of light structured packing in the bed layer, the moisture in the waste water is brought into the air to obtain damp and hot air and concentrated solution, the obtained concentrated solution flows to the bottom of the tower and enters the waste water in a system to enter a concentrated solution circulation pipeline 4 for waste water concentration and circulation, and at the moment, the cold and dry air in. As shown in figure 1, damp and hot air in a humidifying tower 1 is pumped into a dehumidifying tower 8 by an inter-tower fan 7, cooled clear liquid is distributed on a packing bed layer 9 through a water distributor 2 in the dehumidifying tower 8 and flows to the tower bottom under the action of gravity, the damp and hot air and the cooled clear liquid perform mass and heat transfer on the surface of the packing bed layer 9, the contact area of the clear liquid and the flowing air is enlarged through a large amount of light structured packing in the bed layer, water is separated out when gaseous water vapor in the damp and hot air reaches a condensation dew point to obtain water drops and air which rises to the tower top after being dehumidified, the obtained water drops flow into liquid water drops to enter the clear liquid due to condensation of the gaseous water vapor in the air, the obtained water drops flow to the tower bottom to perform dehumidifying circulation on the air, the dehumidified air enters an air circulation pipeline 3 from a dehumidifying air outlet E and then enters a tower bottom air distribution disc 11 in the humidifying tower 1 to form dry and humid air, continuously concentrating the wastewater.
As shown in figure 1, the hyperconcentration accumulated at the bottom of the humidifying tower is discharged from a hyperconcentration discharge pipe 16 to a dryer 18 through a concentrated solution lift pump for secondary concentration and drying, and the dried solid is backfilled.
Claims (13)
1. The utility model provides a concentrated system of waste water based on air is humidified, is dehumidified which characterized in that: comprises a humidifying unit, a dehumidifying unit, a dry and wet air circulating unit and a heat exchange unit;
the humidifying unit is used for concentrating and circulating wastewater and comprises a humidifying tower and a concentrated solution circulating pipeline, a water distributor is arranged at the upper part of the humidifying tower, a tower bottom gas distribution disc is arranged at the lower part of the humidifying tower, a packing bed layer used for increasing the contact area of a liquid phase and a gas phase is arranged between the water distributor and the tower bottom gas distribution disc of the humidifying tower, a wastewater inlet A and a cold side heat exchange port B are sequentially and downwards arranged at the lower part of the tower bottom gas distribution disc of the humidifying tower, one end of the concentrated solution circulating pipeline is communicated with the water distributor in the humidifying tower, and the other end of the concentrated solution circulating pipeline is communicated with the cold;
the dehumidification unit is used for dehumidifying and circulating air and comprises a dehumidification tower and a clear liquid circulation pipeline, wherein a water distributor is arranged at the upper part of the dehumidification tower, a dehumidification air outlet E is arranged at the top part of the dehumidification tower, a packing bed layer used for increasing the contact area of a liquid phase and a gas phase is arranged at the lower part of the water distributor of the dehumidification tower, a clear liquid water inlet C and a hot side heat exchange port D are sequentially and downwards arranged at the lower part of the dehumidification tower, one end of the clear liquid circulation pipeline is communicated with the water distributor in the dehumidification tower, and the other end of the clear liquid circulation pipeline is communicated with the hot side;
the dry and wet air circulation unit is used for closed air circulation of the humidifying tower and the dehumidifying tower and comprises an inter-tower fan and an air circulation pipeline, the inter-tower fan is arranged on the inter-tower pipeline, one end of the inter-tower pipeline is connected and communicated with the humidifying tower, the other end of the inter-tower pipeline is connected and communicated with the dehumidifying tower, one end of the air circulation pipeline is connected and communicated with a dehumidifying air outlet E of the dehumidifying tower, and the other end of the air circulation pipeline is connected and communicated with a tower bottom air distribution disc of the humidifying tower;
the heat exchange unit comprises a main heat exchanger, a first auxiliary heat exchanger and a second auxiliary heat exchanger, a concentrated liquid lifting pump, a heat main heat exchanger and a first auxiliary heat exchanger which are used for heat exchange step by step are sequentially connected to a concentrated liquid circulating pipeline, a clear liquid lifting pump, a main heat exchanger and a second auxiliary heat exchanger which are used for heat exchange step by step are sequentially connected to a clear liquid circulating pipeline, waste water in the concentrated liquid circulating pipeline and clear liquid in the clear liquid circulating pipeline exchange heat once in the main heat exchanger, and a super concentrated liquid discharge pipe is further connected to the front side of the heat main heat exchanger through the concentrated liquid circulating pipeline.
2. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: the water distributor comprises a porous water distribution ring pipe and a first-stage sieve pore water distribution plate positioned at the lower part of the porous water distribution ring pipe, a plurality of spray heads are uniformly distributed on the porous water distribution ring pipe, and the number of water outlets on the first-stage sieve pore water distribution plate is larger than that of the spray heads on the porous water distribution ring pipe.
3. The air humidification and dehumidification-based wastewater concentration system according to claim 2, wherein the system comprises: the porous water distribution ring pipe comprises at least more than two pipe rings with different sizes and an intermediate communicating pipe, each pipe ring is communicated through at least two intermediate communicating pipes, and a pipe section extending outwards from the intermediate communicating pipe is arranged at an interface.
4. The air humidification and dehumidification-based wastewater concentration system according to claim 2, wherein the system comprises: the water-locator still has the second grade sieve mesh water distribution plate that is located one-level sieve mesh water distribution plate lower part, and the apopore aperture on the second grade sieve mesh water distribution plate is less than the apopore aperture on the one-level sieve mesh water distribution plate, and the apopore on the second grade sieve mesh water distribution plate sets up with the apopore on the one-level sieve mesh water distribution plate in a mutually wrong way.
5. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: the packing bed layers in the humidifying tower and the dehumidifying tower are single layers or multiple layers arranged at intervals, and the packing bed layers are filled with a plurality of pall ring packings, Raschig ring packings or saddle ring packings.
6. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: the pipeline between the towers is connected with a plurality of branch pipes which are connected in parallel at the rear part of the fan between the towers, the lower part of the dehumidification tower corresponding to the packing bed layer is also provided with a gas distribution disc, and the plurality of branch pipes are communicated with the respective corresponding gas distribution discs.
7. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: the dehumidification tower is characterized in that a plurality of pipelines are arranged among the towers, the lower portion of the corresponding packing bed layer is provided with an air distribution disc, one end of each pipeline among the towers is connected to the humidification tower at intervals, and the other end of each pipeline among the towers is connected to the corresponding air distribution disc.
8. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: the concentrated solution circulation pipeline is connected with a filter on the liquid inlet front side of the concentrated solution lift pump, and the clear solution circulation pipeline is connected with a filter on the liquid inlet front side of the clear solution lift pump.
9. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: the first auxiliary heat exchanger is communicated with industrial waste/waste heat, and the second auxiliary heat exchanger is communicated with condensed water of the cooling water tower.
10. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: and the humidifying tower, the dehumidifying tower, the concentrated solution circulating pipeline, the clear solution circulating pipeline, the air circulating pipeline and the inter-tower pipeline are all externally coated with heat insulating layers.
11. The air humidification and dehumidification-based wastewater concentration system according to claim 1, wherein the system comprises: the wastewater inlet A of the humidifying tower is communicated with a wastewater inlet pipe, the wastewater inlet pipe is communicated with a water outlet of a pretreatment unit, and the pretreatment unit is used for removing hardness ions in wastewater and preheating the wastewater.
12. The concentration method of the air humidification and dehumidification-based wastewater concentration system according to any one of claims 1 to 11, comprising:
adding wastewater which is pretreated and is free of hardness ions in a water body into the lower part of the tower from a water inlet A of a humidifying tower, enabling the wastewater to enter a concentrated solution circulating pipeline from a cold side heat exchange port A of the humidifying tower, enabling clear solution to enter a clear solution circulating pipeline from a clear solution water inlet C of a dehumidifying tower, and enabling the humidifying tower and the dehumidifying tower to be in a normal pressure state;
starting a concentrated solution lift pump and a clear solution lift pump, wherein the waste water is lifted by the concentrated solution lift pump to be conveyed to a cold side fluid inlet end of a main heat exchanger, the clear solution is lifted by the clear solution to be conveyed to a hot side fluid inlet end of the main heat exchanger, the waste water and the clear solution carry out primary heat exchange in the main heat exchanger, then enter a first auxiliary heat exchanger, carry out secondary heat exchange and then convey into a water distributor at the upper part of a humidifying tower, and the clear solution after primary temperature reduction enters a second auxiliary heat exchanger, is cooled for the second time and then enters the water distributor of the dehumidifying;
the waste water is distributed on a packing bed layer through a water distributor in the humidifying tower and flows towards the tower bottom under the action of gravity, the air dehumidified in the dehumidifying tower is introduced into a tower bottom air distribution disc of the humidifying tower through an air circulation pipeline and flows upwards, mass transfer and heat transfer are carried out on the air and the waste water in the convection mode on the surface of the packing bed layer, moisture in the waste water is carried into the air to obtain damp hot air and concentrated liquid, the obtained concentrated liquid flows to the tower bottom and the waste water entering a system to enter a concentrated liquid circulation pipeline to form waste water concentration circulation, the damp hot air in the humidifying tower is pumped into the dehumidifying tower by an inter-tower fan, clear liquid is distributed on the packing bed layer through the water distributor in the dehumidifying tower and flows towards the tower bottom under the action of gravity, the mass transfer and heat transfer are carried out on the damp hot air and the cooled clear liquid on the surface of the packing bed layer, moisture is separated out when gaseous water vapor in the damp hot air reaches a condensation dew point, water, and the obtained water drops flow to the tower bottom to perform dehumidification circulation on air, and the dehumidified air enters an air circulation pipeline through a dehumidification air outlet E and then enters a tower bottom air distribution disc in the humidifying tower to form dry and wet air circulation.
13. The concentration method of the air humidification and dehumidification-based wastewater concentration system according to claim 12, comprising the steps of: the method is characterized in that: and discharging the super-concentrated solution collected at the bottom of the humidifying tower from a super-concentrated solution discharge pipe to a dryer through a concentrated solution lifting pump for secondary concentration and drying, and backfilling the dried solid matters.
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| CN202010420964.7A CN111453915A (en) | 2020-05-18 | 2020-05-18 | Wastewater concentration system based on air humidification and dehumidification and concentration method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112678903A (en) * | 2020-12-30 | 2021-04-20 | 北京首创环境科技有限公司 | Salt-containing wastewater treatment equipment and method |
| CN112960716A (en) * | 2021-02-18 | 2021-06-15 | 同济大学 | Aeration type humidification, dehumidification and evaporation system and method |
-
2020
- 2020-05-18 CN CN202010420964.7A patent/CN111453915A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112678903A (en) * | 2020-12-30 | 2021-04-20 | 北京首创环境科技有限公司 | Salt-containing wastewater treatment equipment and method |
| CN112678903B (en) * | 2020-12-30 | 2022-12-02 | 北京首创环境科技有限公司 | Salt-containing wastewater treatment equipment and method |
| CN112960716A (en) * | 2021-02-18 | 2021-06-15 | 同济大学 | Aeration type humidification, dehumidification and evaporation system and method |
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