CN210340599U - Device for concentrating waste water by using low-grade flue gas - Google Patents
Device for concentrating waste water by using low-grade flue gas Download PDFInfo
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- CN210340599U CN210340599U CN201920958105.6U CN201920958105U CN210340599U CN 210340599 U CN210340599 U CN 210340599U CN 201920958105 U CN201920958105 U CN 201920958105U CN 210340599 U CN210340599 U CN 210340599U
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- 239000003546 flue gas Substances 0.000 title claims abstract description 101
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 71
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Abstract
本实用新型公开了一种利用低品位烟气浓缩废水的装置。该装置用于解决电厂烟气余热回收和废水浓缩问题，由除尘单元、脱硫单元、省煤器和废水浓缩系统等组成。该装置利用燃煤电厂或其他行业烟气余热进行废水浓缩，浓缩过程对烟气湿度影响很小，将废水变为可用之水，最终将所回收烟气热量传递至低加系统，实现热能梯级利用。浓缩减量后的高浓度废水可送至蒸发干燥系统，大大降低蒸发干燥系统所需热量，减少对机组的影响，整个系统具有能耗低、投资少、运行费用低等优点。
The utility model discloses a device for concentrating wastewater by utilizing low-grade flue gas. The device is used to solve the problem of waste heat recovery and waste water concentration of power plant flue gas, and is composed of dust removal unit, desulfurization unit, economizer and waste water concentration system. The device utilizes the waste heat of flue gas from coal-fired power plants or other industries to concentrate waste water. The concentration process has little effect on the humidity of flue gas, turns waste water into usable water, and finally transfers the recovered flue gas heat to the low-charging system to achieve thermal energy cascades. use. The high-concentration wastewater after concentration and reduction can be sent to the evaporative drying system, which greatly reduces the heat required by the evaporative drying system and reduces the impact on the unit. The entire system has the advantages of low energy consumption, low investment, and low operating costs.
Description
Technical Field
The utility model belongs to the technical field of the environmental protection, concretely relates to utilize device of concentrated waste water of low-grade flue gas, in particular to be arranged in thermal power factory flue gas waste heat recovery in coordination with desulfurization waste water treatment or flue gas waste heat recovery in coordination with waste water treatment in other fields device.
Background
At present, the wet desulphurization wastewater treatment mainly adopts a three-header pretreatment, clarification tank and dehydrator technology, which can remove part of heavy metals and reduce part of SS and turbidity, but can not remove chloride ions, and the treated wastewater does not go out. The technologies currently under study are deep pretreatment, concentration and decrement, and evaporation and drying.
Wherein, the deep pretreatment comprises dosing, clarification and filtration; the concentration decrement can be determined by thermal method (MED, MVR, NED) and membrane method (UF/RO); the evaporation drying is drying by using the waste heat of steam or smoke. The steam evaporation is adopted to generate recoverable salt, so that the water recycling in the wastewater is realized, and the defects of difficult recycling because the recovered salt is low-grade salt, high-quality steam in the evaporation process, high energy consumption, large investment and high operation requirement are overcome. The adoption of the flue gas waste heat evaporation scheme has the advantages of low investment and low operating cost, and simultaneously improves the downstream dust removal efficiency, and has the defects of low investment, low operating cost, low waste heat consumption, low unit efficiency due to the influence on the flue gas temperature of the air preheater, increased load of dust removal equipment, low water consumption due to the fact that a large amount of water enters a desulfurization system if concentration and reduction are not carried out, reduced evaporation capacity of a desulfurization tower due to the fact that the desulfurization flushing water amount is influenced, and the amount of treated wastewater is also limited by the flue gas temperature and the.
Therefore, the existing desulfurization wastewater concentration technology has the problems of high-quality heat energy consumption, high investment cost, high operation requirement, adverse influence on unit efficiency and the like.
SUMMERY OF THE UTILITY MODEL
Therefore, the to-be-solved technical problem of the utility model is that there is high-quality heat energy of consumption in the concentrated technique of current desulfurization waste water, and the energy consumption is high, investment cost is big, and the operation requires highly, has defects such as adverse effect to unit efficiency to an utilize the concentrated waste water of low-grade flue gas device is provided.
Therefore, the utility model provides a technical scheme as follows:
the device for concentrating waste water by using low-grade flue gas, provided by the utility model, comprises a dust removal unit and a desulfurization unit which are communicated, and also comprises a coal economizer which is arranged between the dust removal unit and the desulfurization unit or arranged at the upstream of the dust removal unit along the flue gas circulation direction, and also comprises a waste water concentration system which comprises,
the first heat exchanger is communicated with the economizer so as to exchange heat between the desulfurization waste water and a first heat exchange medium from the economizer in the first heat exchanger;
the flash tank comprises a shell and a concentrated wastewater outlet arranged at the lower part of the shell, and the shell is communicated with the first heat exchanger so as to send the heated desulfurization wastewater into the flash tank for flash evaporation;
the second heat exchanger is communicated with the concentrated wastewater outlet so as to exchange heat between the concentrated wastewater and a second heat exchange medium in the second heat exchanger;
and the sedimentation device is communicated with the second heat exchanger so as to send the concentrated waste water after being cooled into the sedimentation device for sedimentation.
Further, the sedimentation device comprises at least two stages of sedimentation units so as to carry out multi-stage sedimentation on the concentrated wastewater after temperature reduction;
the upper part of the settling device is communicated with the first heat exchanger, so that the supernatant and/or the additional desulfurization wastewater in the settling device enter the first heat exchanger and exchange heat with a first heat exchange medium from the economizer in the first heat exchanger.
Further, the device also comprises an evaporation drying unit which is communicated with the lower part of the sedimentation device so as to send the concentrated desulfurization wastewater at the lower part of the sedimentation device into the evaporation drying unit;
and the air preheater is arranged on an upstream flue of the dust removal unit.
Furthermore, the evaporation drying unit is a flue spray evaporator, and the flue spray evaporator is arranged in an upstream flue of the dust removal unit along the circulation direction of the flue gas.
Furthermore, the evaporation drying unit is a rotary spray evaporator, a high-temperature dry flue gas inlet is arranged at the upper part of the evaporation drying unit, and the high-temperature dry flue gas inlet is communicated with an upstream flue of the air preheater along the circulation direction of flue gas, so that the high-temperature dry flue gas in the upstream flue of the air preheater enters the rotary spray evaporator to exchange heat with the concentrated desulfurization wastewater;
the lower part of the rotary spraying evaporator is provided with a high-temperature wet flue gas outlet, the high-temperature wet flue gas outlet is communicated with a flue between the air preheater and the dust removal unit, and the communication point of the sedimentation device and the rotary spraying evaporator is positioned on the upper part of the rotary spraying evaporator.
And the third heat exchanger is communicated with the second heat exchanger, so that the heated second heat exchange medium from the second heat exchanger enters the third heat exchanger and exchanges heat with the secondary steam from the flash tank again.
Further, the high-temperature dry flue gas dust removal device further comprises an air preheater arranged on the upstream flue, the nozzle is arranged in the upstream flue between the air preheater and the dust removal unit, or the high-temperature dry flue gas outlet is communicated with the inlet flue of the air preheater.
The first pump is communicated with the flash tank and is used for enabling the inside of the flash tank to be in a negative pressure state and controlling the vacuum degree inside the flash tank;
the second pump is arranged on a pipeline between the settling device and the first heat exchanger so as to send the supernatant and/or the additional desulfurization wastewater into the first heat exchanger;
and the third pump is arranged on a pipeline between the sedimentation device and the evaporation drying unit.
The fourth pump is arranged on a pipeline between the flash tank and the second heat exchanger;
and the fifth pump is arranged on the water return pipeline or the water inlet pipeline with low addition of the condensed water.
The device further comprises a chimney, wherein the chimney is communicated with the desulfurization unit;
the dust removal unit is an electric dust remover; the coal economizer is a low-temperature coal economizer; the desulfurization unit is a desulfurization tower.
Further, the first heat exchange medium is heat medium water; the second heat exchange medium is low-condensed water.
The utility model discloses technical scheme has following advantage: the desulfurization waste water and a first heat exchange medium from the coal economizer exchange heat in the first heat exchanger; the flash tank comprises a shell and a concentrated wastewater outlet arranged at the lower part of the shell, and the shell is communicated with the first heat exchanger so as to send the heated desulfurization wastewater into the flash tank for flash evaporation; the second heat exchanger is communicated with the concentrated wastewater outlet so as to exchange heat between the concentrated wastewater and a second heat exchange medium in the second heat exchanger; and the sedimentation device is communicated with the second heat exchanger so as to send the concentrated wastewater after being cooled into the sedimentation device for sedimentation. The device utilizes coal fired power plant or other trades flue gas waste heat to carry out waste water concentration, and the concentration process can not lead to the fact obvious change to flue gas humidity, becomes available water with waste water, finally with the low system that adds of the flue gas heat transfer that retrieves to low with the comdenstion water, realizes the heat energy cascade utilization. When the concentrated and reduced high-concentration desulfurization wastewater is subjected to subsequent evaporation drying, the heat required by an evaporation drying system is greatly reduced, the influence on a unit is reduced, and the whole system has the advantages of low energy consumption, low investment, low operating cost and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described 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 diagram of an embodiment of the present invention, illustrating an apparatus for concentrating wastewater by using low-grade flue gas;
FIG. 2 is another schematic structural diagram of an apparatus for concentrating wastewater by using low-grade flue gas in the embodiment of the present invention;
FIG. 3 is a schematic diagram of a wastewater concentration system according to an embodiment of the present invention;
wherein the reference numerals are represented as:
0-air preheater; 1-a dust removal unit; 2-a desulfurization unit; 3-a chimney; 4-a coal economizer; 5-a first heat exchanger; 6-a flash tank; 7-a third heat exchanger; 8-a settling device; 9-a second heat exchanger; 10-a nozzle; 11-a first pump; 12-a second pump; 13-a third pump; 14-a rotary spray evaporator; 15-a fourth pump; 16-fifth pump.
Detailed Description
The technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to 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," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.
Example 1
The embodiment provides a device for concentrating wastewater by using low-grade flue gas, as shown in fig. 1 and 3, comprising a dust removal unit 1 and a desulfurization unit 2 which are arranged in a communicating manner, and further comprising an economizer 4 which is arranged between the dust removal unit 1 and the desulfurization unit 2 or arranged upstream of the dust removal unit 1 along the flue gas flowing direction, in the embodiment, the dust removal unit 1 is an electric precipitator, the economizer 4 is a low-temperature economizer, the desulfurization unit 2 is a desulfurization tower, and further comprising a wastewater concentration system, wherein the wastewater concentration system comprises,
the first heat exchanger 5 is communicated with the economizer 4 so as to exchange heat between the desulfurization wastewater and a first heat exchange medium from the economizer in the first heat exchanger 5, and specifically, the first heat exchange medium is intermediate heat medium water obtained after heat exchange of high-temperature flue gas;
the flash tank 6 comprises a shell and a concentrated wastewater outlet arranged at the lower part of the shell, and the shell is communicated with the first heat exchanger 5 so as to send the heated desulfurization wastewater into the flash tank 6 for flash evaporation;
the second heat exchanger 9 is communicated with the concentrated wastewater outlet so as to exchange heat between the concentrated wastewater and a second heat exchange medium in the second heat exchanger 9, and specifically, the second heat exchange medium is low-addition condensed water from the outside;
the sedimentation device 8 is communicated with the second heat exchanger 9 so as to send the concentrated wastewater after being cooled into the sedimentation device 8 for sedimentation; specifically, the settling device 8 comprises at least two stages of settling units, so that the concentrated wastewater after temperature reduction is subjected to multistage settling; the upper part of the settling device 8 is communicated with the first heat exchanger 5, so that the supernatant and/or the additional desulfurization wastewater in the settling device 8 enter the first heat exchanger 5 and exchange heat with a first heat exchange medium from the economizer 4 in the first heat exchanger 5; more specifically, as shown in fig. 3, the settling device 8 is a three-stage settling unit which is communicated in sequence. And a multi-stage precipitation mode is adopted to ensure that only a small amount of concentrated waste water is sent to an evaporation drying system so as to reduce the influence on the overall efficiency of the unit.
Among the above-mentioned device, utilize coal fired power plant or other trades flue gas waste heat to carry out waste water concentration, the concentration process can not increase flue gas humidity, becomes available water with waste water, finally with the low system that adds of the low comdenstion water of the flue gas heat transfer that retrieves, realizes the heat energy cascade utilization. When the concentrated and reduced high-concentration desulfurization wastewater is subjected to subsequent evaporation drying, the heat required by an evaporation drying system is greatly reduced, the influence on a unit is reduced, and the whole system has the advantages of low energy consumption, low investment, low operating cost and the like.
As shown in fig. 1, the heat exchanger 7 is communicated with a secondary steam outlet at the upper part of the shell, the third heat exchanger 7 is also communicated with the second heat exchanger 9, so that the heated second heat exchange medium from the second heat exchanger enters the third heat exchanger 7 and exchanges heat with the secondary steam from the flash tank 6 again, the secondary steam is changed into secondary steam condensate, and the low condensed water-adding incoming water is changed into low condensed water-adding backwater.
Further, the device also comprises an evaporation drying unit which is communicated with the lower part of the sedimentation device 8 so as to send the concentrated desulfurization wastewater at the lower part of the sedimentation device 8 into the evaporation drying unit; specifically, the evaporation drying unit is a flue spray evaporator (for example, a nozzle 10), and the nozzle 10 is disposed in an upstream flue of the dust removal unit 1 along a flow direction of the flue gas.
Further, the device also comprises an air preheater 0 arranged on an upstream flue of the dust removal unit 1, and a nozzle 10 arranged in the upstream flue between the air preheater 0 and the dust removal unit 1; and the chimney 3 is communicated with the desulfurization unit 2.
In order to control the concentration of chloride ions in the wastewater sedimentation tank, part of the concentrated wastewater is sent to an evaporation drying unit, the evaporation drying unit can adopt a flue sprayer (such as a nozzle 10), the flue sprayer is generally arranged in a flue between the air preheater 0 and the electric dust remover, the atomized concentrated water is evaporated into water vapor by utilizing high-temperature waste heat flue gas in the flue, the vapor enters a desulfurizing tower along with the flue gas after dust removal, and evaporated crystals enter the electric dust remover along with dust and are discharged along with the dust.
The device consists of a low-temperature economizer, a low-temperature phase change wastewater concentration system and an evaporation drying unit. The low-temperature phase-change wastewater concentration system mainly comprises equipment such as a first heat exchanger 5 (a wastewater heater), a flash tank 6 (a wastewater flash tank), a second heat exchanger 9 (a wastewater cooler), a third heat exchanger 7 (a condenser), a sedimentation device 8 (a wastewater sedimentation tank), a vacuum pump (a first pump 11) and a related wastewater delivery pump, and the evaporation drying unit is a flue sprayer (for example, a nozzle 10). If the low-temperature economizer is installed in the original flue gas system, the flue gas system does not need to be modified, only a heating medium water pipeline of the low-temperature economizer needs to be modified, and a pipeline which is directly sent to the low-temperature economizer is cut off and is connected to a low-temperature phase-change wastewater concentration system. If the flue gas system is not provided with the low-temperature economizer, the low-temperature economizer needs to be additionally arranged to recycle the heat of the original flue gas. The water temperature of the low-temperature intermediate heat medium water is above 70 ℃, in order to utilize the waste heat of the flue gas and prevent low-temperature corrosion to the maximum extent, the water temperature of the intermediate heat medium water is selected to be 70 ℃, and the water temperature of the intermediate heat medium water is raised to about 95 ℃ after heat exchange with the flue gas. The heated intermediate heat medium water is sent to a wastewater heater to exchange heat with the desulfurization wastewater, the temperature of the incoming water of the general wastewater is about 35 ℃, the desulfurization wastewater can be heated to 65-75 ℃, the heated wastewater enters a wastewater flash tank to be subjected to negative pressure flash evaporation, the flash evaporation temperature is 55-65 ℃, the concentrated wastewater after concentration comes out from the bottom of the flash tank and is sent to a wastewater cooler, low-pressure condensation water is used for exchanging heat with the concentrated wastewater, the low-pressure condensation water after primary heat exchange and secondary steam at the top of the wastewater flash tank exchange heat in a condenser, the secondary steam condensation water can be used for water supplement in the desulfurization tower process, the heated low-pressure condensation water returns to a low-pressure system, and recovery of the waste heat of the flue gas is completed. And sending the cooled concentrated wastewater to a wastewater sedimentation tank, carrying out multi-stage sedimentation, and sending the supernatant and the new desulfurization wastewater to a wastewater heater for reheating and cyclic concentration.
Example 2
In this embodiment, as shown in fig. 2 and 3, on the basis of the above embodiment 1, as a variable implementation manner, the evaporation drying unit is a rotary spray evaporator 14, and a high-temperature dry flue gas inlet is arranged at the upper part of the rotary spray evaporator, and the high-temperature dry flue gas inlet is communicated with an upstream flue of the air preheater 0 along the flow direction of flue gas, so that the high-temperature dry flue gas in the upstream flue of the air preheater 0 enters the rotary spray evaporator to exchange heat with the concentrated desulfurization wastewater; specifically, a high-temperature dry flue gas inlet is communicated with an inlet flue of the air preheater 0;
the lower part of rotatory spraying evaporator is provided with the export of wet flue gas of high temperature, the export of wet flue gas of high temperature communicates with the flue between air preheater 0 and the dust removal unit 1, specifically, the export of wet flue gas of high temperature communicates with the entry flue of dust removal unit 1, and for the intercommunication point of high temperature dry flue gas import and upper reaches flue, the export of wet flue gas of high temperature is close to dust removal unit 1 with the intercommunication point of upper reaches flue, the intercommunication point of subsidence device 8 and rotatory spraying evaporator is located the upper portion of rotatory spraying evaporator, specifically, the intercommunication point of subsidence device 8 and rotatory spraying evaporator is located the top of rotatory spraying evaporator.
In the operating condition, the evaporation drying unit can adopt an independently rotating spray drying tower, the independently rotating spray drying tower is arranged outside a flue gas system, a flue gas bypass is arranged, a small part of flue gas at the outlet of the denitration SCR is extracted to the spray drying tower, desulfurization wastewater is sprayed into the spray drying tower and evaporates the atomized concentrated water into water vapor by using the heat of the flue gas in the spray drying tower, the flue gas at the outlet of the spray drying tower enters the inlet flue of the dust removal unit, the vapor enters the desulfurization tower along with the flue gas after dust removal, and evaporative crystals enter the electric dust remover along with dust to be captured and discharged along with the dust. And discharging the concentrated and dried solid salt from the bottom of the spray drying tower.
Example 3
The embodiment provides a device for concentrating wastewater by using low-grade flue gas, which, on the basis of the embodiment 1 or 2, further comprises a first pump 11, which is communicated with the flash tank 6 and is used for enabling the interior of the flash tank 6 to be in a negative pressure state and controlling the vacuum degree in the flash tank 6; in order to ensure that the heated wastewater can be subjected to flash evaporation concentration, a low-temperature phase change concentration system needs to be matched with a vacuum pump (namely a first pump 11), the vacuum pump is connected with a wastewater flash tank and a condenser in series, secondary steam is firstly cooled in the condenser after the condenser, phase change occurs in the cooling process to generate negative pressure, the negative pressure state of the system can be maintained, the system is started and the vacuum degree is kept stable, the vacuum pump needs to be arranged, the vacuum pump performs vacuum pumping when the system is started, only non-condensable gas precipitated by condensation water of the secondary steam needs to be pumped in the operation process, and the power consumption of the vacuum pump is reduced while the vacuum degree of the system;
a second pump 12 disposed on the pipe between the settling device 8 and the first heat exchanger 5 to send the supernatant and/or the additional desulfurization wastewater into the first heat exchanger 5;
and a third pump 13 arranged on the pipeline between the settling device 8 and the evaporation drying unit.
A fourth pump 15 disposed on the pipe between the flash tank 6 and the second heat exchanger 9;
and the fifth pump 16 is arranged on a water return pipeline or a water inlet pipeline of low condensed water.
In addition, it should be noted that the water quality and water quantity characteristics of the desulfurization wastewater are related to a plurality of factors such as unit load, coal components, operation conditions, desulfurization process water quality, limestone components and the like, and the desulfurization wastewater has the characteristics of complex pollutant components, large fluctuation range and the like, has a low pH value, is acidic, has high content of suspended matters in water, high salt content, high possibility of exceeding the standard of heavy metals, has high chlorine root content and strong corrosivity, and is the wastewater which is the most difficult to treat in a power plant. Carry out decrement concentration then need a large amount of high-quality evaporation or flue gas to desulfurization waste water, the energy consumption is high again, no matter utilize flue gas waste heat before unit extraction of steam or the air preheater all can cause harmful effects to the unit, in order to solve this problem, the utility model discloses a flue gas waste heat recovery is concentrated device of waste water in coordination, the device is retrieved former flue gas heat through arranging the low temperature economizer before the electrostatic precipitator or after with, and the heat of retrieving is delivered to waste water heater by the heat medium water, heats up the waste water that the waste water sedimentation tank sent, and waste water entering waste water flash tank after the intensification, flash tank are negative pressure, and its vacuum is provided by the vacuum pump, and the vacuum pump establishes ties with the condenser, is located after the condenser. The concentrated wastewater after flash evaporation enters a wastewater cooler from the bottom of a flash tank, the heat carried by the concentrated wastewater is used for heating low condensation water for the first time, the concentrated wastewater after cooling enters a wastewater sedimentation tank, fractional sedimentation is carried out, supernatant and new desulfurization wastewater are circulated to a wastewater heater again, a small amount of concentrated wastewater at the bottom of the wastewater sedimentation tank is sent to a flue sprayer in front of an electric dust remover, the atomized concentrated water is evaporated into water vapor by using high-temperature waste heat flue gas in the flue, the vapor enters a desulfurization tower along with the flue gas after dust removal, and evaporated and dried substances enter the electric dust remover along with dust and are discharged along with ash; or the flue gas is sent to an independently rotating spray evaporation tower for evaporation and drying, a small part of flue gas at the outlet of the denitration SCR is extracted to the evaporation tower, the desulfurization wastewater is sprayed into the evaporation tower, the atomized concentrated water is evaporated into water vapor in the evaporation tower by using the heat of the flue gas, the flue gas at the outlet of the evaporation tower enters the inlet flue of a dust remover, and the vapor enters the desulfurization absorption tower along with the flue gas after dust removal; the evaporated crystal enters the electric dust remover along with dust to be captured and discharged along with the dust. And the secondary steam obtained by flash evaporation enters a condenser from the top of the flash evaporation tank, low-addition condensation water is secondarily heated in the condenser, the secondarily heated low-addition condensation water returns to a low-addition circulating water system with the temperature close to that of the low-addition condensation water, and the secondary steam condensation water is used for process water supplement of a desulfurization system. Through this device, the flue gas heat that low temperature was retrieved is used for desulfurization waste water concentration earlier, has solved the drawback that conventional route utilized high-quality heat energy evaporation, simultaneously, gives the heat transfer that contains it after the waste water concentration and adds the condensate water system lowly, makes the heat not have outer row, obtains abundant cascade utilization, satisfies desulfurization promptly and abolishes the required heat of processing and does not lose how much heat again, and its most heat finally transmits to lowly and adds the condensate water to reduce the unit energy consumption.
The device can fully utilize the low-temperature coal economizer of the existing flue gas waste heat recovery equipment of the power plant, and if the flue gas waste heat recovery is not improved, the low-temperature coal economizer needs to be additionally arranged in front of or behind the electric dust collector. The conventional technology is through low temperature economizer with flue gas system waste heat recovery be used for heating low condensation water or air heater, and desulfurization waste water concentration system is added to this device, utilizes the heat of retrieving earlier to carry out the concentration to waste water, and rethread cooler and condenser give the low condensation water of adding with dense waste water and secondary steam heat transfer, and the flue gas heat of retrieving in-process hardly loses, only the quality reduces to some extent. The concentration system and the evaporation crystallization system are independent of a flue gas system and can be adjusted according to the load change of the unit.
The utility model discloses the technical effect that can realize is: the low-temperature coal economizer arranged in front of or behind the electric dust remover recovers the waste heat of the flue gas, so that the dust removal capacity of the electric dust remover can be improved, and the water supplement of the process water of the desulfurizing tower can be reduced. In the waste water concentration system, the heat recovered by using the flue gas is used for improving the temperature of the desulfurization waste water, the waste water after heating up is subjected to flash evaporation in a waste water flash evaporation tank, so that the concentration of the desulfurization waste water is realized, the flash evaporation tank is in a negative pressure state, the vacuum degree of the flash evaporation tank is provided by a vacuum pump, the recovered flue gas heat is taken out along with the concentrated waste water and secondary steam, the heat contained in the concentrated waste water and the condensed secondary steam is recovered by using low condensation water, and finally the heat is returned to the low condensation water system. Concentrated wastewater is pumped to a wastewater sedimentation tank through a wastewater pump, after multi-stage sedimentation, supernatant is recycled to a wastewater heater along with newly entered desulfurization wastewater, and a small amount of high-concentration wastewater is sent to an evaporation drying unit to control the chloride ion concentration of the wastewater of a concentration system. When the flue gas is sent to a flue spray evaporator, the atomized concentrated water is evaporated into water vapor by using high-temperature waste heat flue gas in the flue, the vapor enters a desulfurizing tower along with the flue gas after dust removal, and evaporated crystals enter an electric precipitator along with dust and are discharged along with the dust; or the flue gas is sent to an independently rotating spray evaporation tower for evaporation and drying, a small part of flue gas at the outlet of the denitration SCR is extracted to the evaporation tower, the desulfurization wastewater is sprayed into the evaporation tower, the atomized concentrated water is evaporated into water vapor in the evaporation tower by using the heat of the flue gas, the flue gas at the outlet of the evaporation tower enters an inlet flue of a dust remover, and the vapor enters a desulfurization absorption tower along with the dedusted flue gas; the evaporated crystal enters the electric dust remover along with dust to be captured and discharged along with the dust. Through the mode, the problem of flue gas waste heat recovery of a coal-fired power plant or other industries is solved, and meanwhile, the waste water concentration is realized. The system has the advantages of low energy consumption, low investment, low operating cost, high-efficiency energy conservation, emission reduction and other environmental protection effects, and has good social and economic influences.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications can be made without departing from the scope of the invention.
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| CN110183024A (en) * | 2019-06-24 | 2019-08-30 | 中国华电科工集团有限公司 | A kind of device using low-grade flue gas concentration waste water |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110183024A (en) * | 2019-06-24 | 2019-08-30 | 中国华电科工集团有限公司 | A kind of device using low-grade flue gas concentration waste water |
| CN110183024B (en) * | 2019-06-24 | 2025-01-24 | 中国华电科工集团有限公司 | A device for concentrating wastewater using low-grade flue gas |
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