CN212292894U - Concentrated system of desulfurization waste water based on decanoic acid extraction - Google Patents
Concentrated system of desulfurization waste water based on decanoic acid extraction Download PDFInfo
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- CN212292894U CN212292894U CN202021897849.0U CN202021897849U CN212292894U CN 212292894 U CN212292894 U CN 212292894U CN 202021897849 U CN202021897849 U CN 202021897849U CN 212292894 U CN212292894 U CN 212292894U
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Abstract
The utility model relates to a desulfurization waste water concentration system based on decanoic acid extraction, which comprises a heater, a mixer, a delivery pump, a first separator, a decanoic acid solution tank, a water production tank, a second separator and a first cooler; the outlet of the heater and the outlet of the conveying pump are respectively connected with the inlet of the mixer, and the outlet of the mixer is connected with the inlet of the first separator; the first separator is sequentially connected with the first cooler and the second separator; one outlet of the second separator is connected with a decanoic acid solution tank, and is connected to the inlet of the heater through the decanoic acid solution tank, and the other outlet of the second separator is connected with a water production tank; mixing capric acid and desulfurization wastewater in a mixer to form mixed emulsion, and separating aqueous capric acid emulsion and desulfurization wastewater concentrated solution by a first separator; after passing through a first cooler, the aqueous capric acid emulsion enters a second separator to separate a capric acid solution and water; sending the decanoic acid solution into a decanoic acid solution tank, and then conveying the decanoic acid solution to a heater for recycling; the water separated by the second separator is discharged into a water production tank. The utility model discloses can reduce the equipment investment.
Description
The technical field is as follows:
the utility model relates to a coal fired power plant waste water treatment field specifically is a concentrated system of desulfurization waste water based on decanoic acid extraction.
Background art:
the existing desulfurization wastewater treatment technology needs to soften the desulfurization wastewater to be treated (remove scale-causing ions such as calcium, magnesium and the like), and comprises chemical softening and membrane method softening.
In the chemical softening process, because the desulfurization wastewater contains high-concentration scaling ions such as calcium, magnesium, strontium and barium, a large amount of chemical softening agents are required to be added, the agent cost is very high, and the chemical softening process occupies most of the agent cost of a zero-emission system; large-scale chemical softening process equipment is built, the occupied area is large, and the investment is high; a large amount of chemical softening sludge is generated, and the disposal cost is high; the TDS of the produced water does not fall and reversely rises, the burden of subsequent concentration reduction and tail end solidification is increased, and the investment and operating cost of concentration reduction and tail end solidification are increased.
The softened desulfurization wastewater is concentrated, and the existing desulfurization wastewater concentration technology comprises a heat concentration technology and a membrane concentration technology.
The thermal concentration technology is to continuously heat the wastewater by using a heat source so as to continuously evaporate water and continuously concentrate the wastewater, and finally obtain distilled water for recycling and solidifying a concentrated solution. The evaporation concentration process is usually high in cost because a large amount of heat is consumed for water-vapor phase change. There are mainly the following problems: 1) because the high-salinity wastewater has strong corrosivity, all equipment parts in contact with the wastewater use expensive metal materials, so that the equipment cost is high; 2) because the heat transfer surface of steam and waste water is extremely important, if the heat exchange surface forms scale, the system performance is greatly reduced, and the requirement of the technology on waste water pretreatment is very high; 3) when the salinity of the wastewater is high, the corresponding boiling point rise is also high (for example, the boiling point of a sodium chloride solution rises to 13 ℃ under the saturated concentration condition), and the energy efficiency of the evaporation concentration technology is not high at this time, so that the operation cost is increased. Therefore, the problems of high investment, high operation and maintenance cost, large occupied area, serious equipment scaling and corrosion and the like generally exist.
The membrane concentration is mainly high-pressure Reverse Osmosis (RO), Forward Osmosis (FO), Membrane Distillation (MD), Electrodialysis (ED), vibration membrane concentration process and the like, wherein: forward Osmosis (FO) can be concentrated to TDS less than or equal to 18 ten thousand ppm, high-pressure Reverse Osmosis (RO) can be concentrated to TDS less than or equal to 10 ten thousand ppm, the investment, operation and maintenance cost and the occupied area are slightly lower than those of a thermal concentration technology, and the following problems mainly exist: 1) in order to prevent the membrane element from being polluted and blocked, the pretreatment requirement on the wastewater is higher, so that the investment and operation and maintenance cost of the pretreatment are increased; 2) the membrane elements are continuously deteriorated in the operation process and need to be cleaned and replaced regularly, so that the operation and maintenance cost is increased; 3) the membrane technology limits the concentration multiple of the wastewater to be lower, the discharge amount of the concentrated water is higher than that of the MVC/MED thermal concentration technology, and the investment and operation and maintenance cost of terminal treatment are increased; 4) the problems of difficult cleaning, short cleaning period and service life, poor load impact resistance and the like of the membrane system generally exist.
The invention content is as follows:
in order to solve the problem that the concentrated technique of current desulfurization waste water exists, the utility model provides a concentrated system of desulfurization waste water based on decanoic acid extraction.
The scheme of the utility model is as follows:
a desulfurization wastewater concentration system based on capric acid extraction comprises a heater, a mixer, a delivery pump, a first separator, a capric acid solution tank, a water production tank, a second separator and a first cooler; the outlet of the heater and the outlet of the conveying pump are respectively connected with the inlet of the mixer, and the outlet of the mixer is connected with the inlet of the first separator; the first separator is sequentially connected with the first cooler and the second separator; one outlet of the second separator is connected with a decanoic acid solution tank, and is connected to the inlet of the heater through the decanoic acid solution tank, and the other outlet of the second separator is connected with a water production tank; mixing capric acid and desulfurization wastewater in a mixer to form mixed emulsion, and separating aqueous capric acid emulsion and desulfurization wastewater concentrated solution by a first separator; after passing through a first cooler, the aqueous capric acid emulsion enters a second separator to separate a capric acid solution and water; sending the decanoic acid solution into a decanoic acid solution tank, and then conveying the decanoic acid solution to a heater for recycling; the water separated by the second separator is discharged into a water production tank.
Furthermore, the desulfurization waste water treatment device further comprises a Venturi ejector, the outlet of the conveying pump is connected with the inlet of the Venturi ejector, the outlet of the Venturi ejector is connected with the inlet of the mixer, and the desulfurization waste water enters the mixer through the injection of the Venturi ejector.
Further, a second cooler and a filter are arranged and are sequentially connected with an outlet of the water production tank; and water separated out by the second separator enters a second cooler for cooling after passing through a water production tank, so that the decanoic acid in the water is crystallized, the water is separated from the decanoic acid solid through a filter, and the separated decanoic acid solid is sent to a heater for recycling.
Furthermore, a heat exchanger is arranged between the first separator and the first cooler, the decanoic acid emulsion separated by the first separator flows into the decanoic acid emulsion box and then is input into the hot end of the heat exchanger through a pump, and the heat-released decanoic acid emulsion enters the first cooler; the decanoic acid solution separated by the second separator enters a decanoic acid solution tank, then is input into the cold end of the heat exchanger through a pump, and the decanoic acid solution after heat absorption is sent into the heater.
Further, the first separator adopts a gravity separator; the second separator is a centrifugal separator.
Furthermore, the gravity separator is in a cone frustum shape with a large upper part and a small lower part, and a perforated plate is arranged on the central plane in the gravity separator; a mixed emulsion input pipe is arranged at the center of the gravity separator, the outlet of the mixed emulsion input pipe is positioned at the lower side of the porous plate, and the mixed emulsion is conveyed to the lower side of the porous plate through the mixed emulsion input pipe; the top of the gravity separator is provided with a capric acid overflow outlet pipe, and the bottom is provided with a desulfurization wastewater concentrated solution siphon outlet pipe.
Further, a temperature sensor is arranged in the mixer; the lower part of the mixer is conical, and the upper part of the mixer is cylindrical; a decanoic acid inlet pipe is arranged in the middle of the lower cone of the mixer, heated decanoic acid overflows into the mixer from the tangential direction along the circumference through the decanoic acid inlet pipe, and the flow direction of the fluid is in the same direction as the stirring rotation direction; a desulfurization waste water inlet pipe is arranged at the center of the bottom of the lower cone of the mixer, and desulfurization waste water enters the mixer from the desulfurization waste water inlet pipe after being pressurized by the delivery pump; the top of the mixer is provided with a mixed emulsion self-overflow pipe, and the mixed emulsion is discharged from the overflow pipe through the mixed emulsion.
Further, the heat exchanger is a jacketed heat exchanger, an immersed coil heat exchanger, a plate-frame heat exchanger or a shell-and-tube heat exchanger; the hot end and the cold end inlets of the heat exchanger are provided with a thermometer, a pressure gauge or a flowmeter.
Further, the first cooler is a natural cooling pond or an open mechanical draft cooling tower; the first cooler is provided with a temperature sensor or a temperature measuring instrument.
Further, the second separator is provided with a temperature sensor or a temperature measuring instrument; the second cooler is a natural cooling pond or an open mechanical ventilation cooling tower.
The utility model discloses an application number is 201820386613.7 the patent a novel high-efficient flocculation processing system of waste water carries out desulfurization waste water preliminary treatment, and output desulfurization waste water preliminary treatment water can satisfy the quality of water requirement of follow-up technology section feeding incoming water.
The utility model utilizes the natural easy acquirement of capric acid, is harmless to human beings and is white crystal when the melting point is lower than 31.5 ℃; although the capric acid is insoluble in water, the capric acid can dissolve and absorb pure water with different masses at different temperatures, and the capric acid has the property of not dissolving and absorbing salt and other impurities.
The utility model discloses regard as the solvent with the decanoic acid, water is as the solute, utilizes the difference that decanoic acid dissolves absorption water ability under the different temperatures, for example: when the temperature is lower than 31.5 ℃, the capric acid is white crystal and does not contain water; the decanoic acid can dissolve and absorb about 5.1 percent of water at the temperature of 62 ℃, so that the heated decanoic acid solution and the desulfurization wastewater pretreatment water are fully stirred and mixed, the water dissolved and absorbed in the decanoic acid solution is saturated, and the desulfurization wastewater pretreatment water is concentrated because the pure water is dissolved and absorbed into the decanoic acid solution; separating the decanoic acid emulsion containing pure water from the concentrated desulfurization wastewater to obtain the decanoic acid emulsion containing pure water and the concentrated desulfurization wastewater; removing the separated desulfurization wastewater concentrated solution from the system, and further carrying out terminal solidification treatment; separating out pure water from the decanoic acid solution by heat exchange and cooling the separated decanoic acid emulsion containing the pure water; separating the decanoic acid solution from the pure water to obtain a substantially water-free decanoic acid solution and pure water respectively; returning the separated substantially water-free decanoic acid solution to the system for recycling; the separated pure water can be reused as a water resource in the industrial process; if trace amount of capric acid contained in the produced pure water needs to be removed, the capric acid can be generated into white crystals by natural cooling to be lower than the melting point of the capric acid, so that the separation of the pure water and the capric acid solid is realized, and the separated capric acid solid is returned to a system for recycling. In addition, the separated capric acid emulsion containing pure water has higher temperature and heat energy, the heat energy is converted into the separated capric acid solution containing substantially no water through the heat exchanger, and the heat energy and the capric acid solution containing substantially no water are returned to the system for recycling, so that the energy consumption is reduced and the efficiency is improved.
Compared with the prior art, the utility model have the following technical effect:
1) the desulfurization wastewater concentration system of the utility model does not need to soften the desulfurization wastewater, and does not need to invest in large-scale softening process equipment for the desulfurization wastewater rich in high-concentration scaling ions; a large amount of chemical softening agents are not required to be added; a large amount of softened sludge does not need to be treated; the investment of softening equipment and structures, the cost of softening agents and softening sludge and the operation and maintenance cost of the softening equipment are saved.
2) Concentrated system of desulfurization waste water, do not receive the restriction of desulfurization waste water salinity, can extensively be applicable to the concentration of various salinity desulfurization waste water to can concentrate desulfurization waste water to the high concentration that is close salinity saturation.
3) Concentrated system of desulfurization waste water, can be in the broad temperature range operation of broad, the various low-grade used heat of make full use of coal fired power plant is as the heat source, and the system has the rate of heat recovery more than 80%, reduces the energy consumption.
4) Concentrated system of desulfurization waste water, because its heating, heat transfer and refrigerated fluid, do not contain strong corrosivity, high scaling thing basically, consequently, heating, heat transfer and cooling arrangement do not need regularly to wash promptly, also need not to use expensive anticorrosive, anti-scaling material preparation, not only can reduce equipment investment by a wide margin, can reduce the working costs by a wide margin moreover.
5) The desulfurization wastewater concentration system of the utility model produces pure water which is basically free of salt and is convenient to recycle to other purposes.
Description of the drawings:
fig. 1 is a schematic view of an embodiment of the present invention;
FIG. 2 is a schematic diagram of a mixer according to an embodiment of the present invention;
fig. 3 is a schematic view of a first separator according to a first embodiment of the present invention;
FIG. 4 is a schematic view of a second embodiment of the present invention;
fig. 5 is a third schematic view of the embodiment of the present invention;
fig. 6 is a fourth schematic view of the embodiment of the present invention;
fig. 7 is a fifth schematic view of an embodiment of the present invention;
in the figure: 1. a perforated plate; 2. a decanoic acid inlet tube; 3. a desulfurization waste water inlet pipe; 4. the mixed emulsion flows from the overflow pipe; 5. a mixed emulsion input pipe; 6. a decanoic acid overflow outlet pipe; 7. and a siphon outlet pipe for the desulfurization wastewater concentrated solution.
The specific implementation mode is as follows:
the first embodiment is as follows:
as shown in fig. 1, the desulfurization waste water concentration system based on decanoic acid extraction of the embodiment includes a heater, a mixer, a delivery pump, a first separator, a second separator, a first cooler, a decanoic acid solution tank and a water production tank.
The outlet of the heater and the outlet of the conveying pump are respectively connected with the inlet of the mixer, and the outlet of the mixer is connected with the inlet of the first separator; the first separator is sequentially connected with the first cooler and the second separator; one outlet of the second separator is connected with a capric acid solution tank, is connected to the inlet of the heater through the capric acid solution tank, and the other outlet is connected with a water production tank.
Heating decanoic acid in a heater, heating to a preset temperature, and injecting into a mixer; and the desulfurization wastewater enters the mixer through the delivery pump. And stirring and mixing the heated decanoic acid and the desulfurization wastewater in a mixer to form mixed emulsion, then feeding the mixed emulsion into a first separator, and separating the mixed emulsion into aqueous decanoic acid emulsion and desulfurization wastewater concentrated solution through the first separator. The decanoic acid emulsion is conveyed to a first cooler, most of water is separated out through cooling, then the decanoic acid emulsion enters a second separator, a cooled decanoic acid solution and water are separated through the second separator, and the cooled decanoic acid solution is conveyed to a heater for recycling.
A temperature sensor is arranged in the heater and used for monitoring the temperature during heating. The heater takes corresponding heat preservation measures to avoid heat loss. The heat source of the heater is electric power, steam, hot flue gas, hot water or other waste heat sources of a coal-fired power plant, or combustible fuels such as solar energy, terrestrial heat, natural gas and diesel oil.
A temperature sensor is arranged in the mixer and used for monitoring the temperature in the mixing process. As shown in figure 2, the mixer is preferably designed to be a lower conical shape and an upper cylindrical shape, a decanoic acid inlet pipe 2 is arranged in the middle of the lower conical body of the mixer, heated decanoic acid flows into the mixer from the tangential direction of the circumference to overflow through the decanoic acid inlet pipe 2, and the flow direction of the fluid is the same as the rotation direction of the stirring. The bottom central point of blender lower part cone puts and is equipped with desulfurization waste water inlet tube 3, and desulfurization waste water is by the delivery pump pressurization back, and from desulfurization waste water inlet tube 3 entering blender. The top of the mixer is provided with a mixed emulsion self-overflow pipe 4, and the mixed emulsion is discharged from the overflow pipe 4 through the mixed emulsion. The mixer takes corresponding heat preservation measures to avoid heat loss. The mixer should be made of anticorrosive material (such as 316L stainless steel, 2205 bidirectional stainless steel and vinyl resin glass fiber reinforced plastics) to resist the strong corrosivity of the desulfurization waste water.
The delivery pump is a corrosion-resistant pump, such as: a tetrafluoro pump. And corresponding water quality detecting instruments (such as a turbidity meter, a PH meter, a conductivity meter and the like) are also arranged for detecting the quality of the incoming water of the desulfurization wastewater.
The first separator is preferably a gravity separator, which is in the shape of a truncated cone with a large top and a small bottom, and the perforated plate 1 is arranged in the center plane of the gravity separator, as shown in fig. 3. The central position of the gravity separator is provided with a mixed emulsion input pipe 5, the outlet of the mixed emulsion input pipe 5 is positioned at the lower side of the porous plate 1, and the mixed emulsion is conveyed to the lower side of the porous plate 1 through the mixed emulsion input pipe 5. The top of the gravity separator is provided with a capric acid overflow outlet pipe 6 for the capric acid to overflow from the top of the gravity separator. And a siphon outlet pipe 7 for the desulfurization wastewater concentrated solution is arranged at the bottom of the gravity separator and is used for sucking the desulfurization wastewater concentrated solution out from the bottom.
Compared with other separation modes, the gravity separation based on the density difference between the decanoic acid emulsion containing pure water and the concentrated solution of the desulfurization wastewater has the advantages of simple equipment structure and no energy consumption.
By arranging the perforated plate 1 at the central plane of the gravity separator, the flow turbulence of the mixed emulsion entering the gravity separator and the influence on the separation of the mixed emulsion can be effectively inhibited. The gravity separator is made into a cone frustum shape with a large top and a small bottom, the speed difference in the gravity direction is caused by the section difference of the equipment, and the separation efficiency of the mixed emulsion is improved by the upward jacking function of the gravity separator.
The mixed emulsion fully mixed by the mixer overflows from the central position of the top of the mixer to the position below the geometric center of the gravity separator. In the mixed emulsion, the desulfurization wastewater is concentrated in advance by dissolving and absorbing pure water into a capric acid solution. The density of the pure water-containing capric acid emulsion is less than that of the concentrated solution of the desulfurization wastewater, the pure water-containing capric acid emulsion floats upwards and is discharged from the top of the gravity separator to a pure water-containing capric acid emulsion box in a self-overflow manner, and the pure water-containing capric acid emulsion is obtained. And (4) the desulfurization wastewater concentrated solution is settled downwards and discharged from the bottom of the gravity separator through a siphon pump, so that the desulfurization wastewater concentrated solution is obtained. Thereby realizing the separation of the decanoic acid emulsion containing pure water in the mixed emulsion and the concentrated solution of the desulfurization waste water. The separated desulfurization waste water concentrated solution is sent to the tail end for solidification and further treatment.
The residence time of the mixed emulsion in the first separator is controlled to be more than 20min, and separation of more than 95% of the desulfurization wastewater concentrated solution and the pure water-containing decanoic acid solution can be realized through gravity separation. In actual engineering, the retention time of the mixed emulsion in the separator is more than or equal to 30min, the complete separation of the concentrated solution of the desulfurization wastewater and the capric acid emulsion containing pure water can be almost realized, and the engineering requirements can be completely met.
The first cooler is a natural cooling pond or an open mechanical ventilation cooling tower and is provided with a temperature sensor or a temperature measuring instrument for monitoring the temperature in the cooling process.
The second separator is a centrifugal separator provided with a temperature sensor or thermometer for monitoring the temperature during centrifugation. Separating the pure water-containing capric acid emulsion by a centrifugal separator to obtain substantially water-free capric acid solution and water, respectively. The separated capric acid solution which is basically free of water is sent into a capric acid solution tank, heated by a pumping heat exchanger to recover heat energy and then returned to the system for recycling; the separated water is sent to a water production tank and can be reused as a water resource in an industrial process.
The centrifugal separator is provided with a temperature sensor and a temperature measuring instrument to monitor the temperature in real time, and corresponding heat preservation measures are taken to avoid heat loss and prevent the capric acid from crystallizing and losing fluidity after the temperature of the solution is lower than the melting point of the capric acid. Because the fluid hardly contains corrosive and highly scaling desulfurization waste water, the centrifugal separator does not need to be prepared by anticorrosive and anti-scaling noble materials, and can meet the engineering requirements by being prepared by common materials (such as carbon steel).
The second cooler is a natural cooling pond or an open mechanical draft cooling tower.
The capric acid has no corrosiveness and does not contain scale-causing ions, the heater, the first cooler and the second separator do not need to be prepared by adopting anticorrosive and anti-scale precious materials, the engineering requirements can be met by adopting the common materials (such as carbon steel), and the equipment investment and the operating cost can be greatly reduced.
According to the desulfurization wastewater concentration system, the softening process is not needed in the concentration process, so that large-scale softening process equipment does not need to be invested, the investment of the softening equipment and structures is saved, and the operation and maintenance cost of the softening equipment is saved.
The desulfurization wastewater concentration system can fully utilize various low-grade waste heat of a coal-fired power plant as heat sources.
Example two:
as shown in fig. 4, this embodiment further includes a venturi ejector on the basis of the first embodiment, the outlet of the delivery pump is connected to the inlet of the venturi ejector, the outlet of the venturi ejector is connected to the inlet of the mixer, and the desulfurization wastewater is injected into the mixer through the venturi ejector.
And the pressure gauge is arranged at the inlet of the venturi ejector to ensure that the inlet pressure of the venturi ejector meets the process requirements of the venturi ejector. And a flowmeter is arranged at the inlet of the Venturi ejector so as to ensure that the mass ratio of the flow of the desulfurization waste water at the inlet to the capric acid solution meets the process requirements.
The particle size of liquid drops of the desulfurization wastewater is controlled to be 90-110 mu m through a Venturi ejector, the liquid drops are ejected into a mixer, and water dissolved in a decanoic acid solution can be saturated within 1min, so that a large amount of time and energy are saved.
Example three:
as shown in fig. 5, in this embodiment, optionally, a second cooler and a filter are further provided, which are connected to the outlet of the water production tank in sequence. And water separated out by the second separator enters a second cooler for cooling after passing through a water production tank, so that trace amount of decanoic acid in the water is generated into white crystals, the density of the decanoic acid is less than that of the water, the white crystals of the decanoic acid float on the water body after the water is cooled to be lower than the melting point of the decanoic acid, and the separation of pure water and the solid decanoic acid can be realized through filtering. Separating pure water from the solid decanoic acid through a filter, and sending the separated solid decanoic acid to a heater for recycling.
By the mode, trace decanoic acid in water can be completely removed to obtain pure water, and the pure water is convenient to be subsequently used in other industrial production.
Further cooling of the pure water-containing capric acid emulsion may be by natural or forced cooling. For most areas, such as sites with sufficient space, natural cooling ponds may be used. For some areas or large-scale projects, natural cooling often cannot meet the project requirements, and an open mechanical ventilation cooling tower is adopted for forced cooling. The open mechanical ventilation cooling tower is specially designed and manufactured according to specific engineering.
The cooled fluid almost does not contain corrosive and highly-scaling desulfurization waste water, and the open mechanical draft cooling tower can meet engineering requirements by being prepared from common materials (such as carbon steel and glass fiber reinforced plastics) without being prepared from anticorrosive and anti-scaling noble materials.
The second cooler is provided with a temperature sensor (such as a thermocouple) and a temperature measuring instrument, and the temperature of the pure water-containing decanoic acid emulsion is monitored in real time.
Example four:
as shown in fig. 6, this embodiment is optional, and further includes a heat exchanger, which is disposed between the separator of the first separator and the first cooler, the decanoic acid emulsion separated by the first separator flows into the decanoic acid emulsion tank, and then is input into the hot end of the heat exchanger through the pump, and the heat-released decanoic acid emulsion enters the first cooler; the decanoic acid solution separated by the second separator enters a decanoic acid solution tank, then is input into the cold end of the heat exchanger through a pump, and the decanoic acid solution after heat absorption is sent into the heater. The heat released in the cooling process of the capric acid emulsion is used as a partial heat source for heating the capric acid solution, so that partial heat can be recovered, and energy conservation and emission reduction are realized.
The heat exchanger is a jacketed heat exchanger, an immersed coil heat exchanger, a plate-frame heat exchanger or a shell-and-tube heat exchanger. The hot end and cold end inlets of the heat exchanger are provided with thermometers, pressure gauges or flow meters for monitoring corresponding data of the hot end and the cold end. Based on the consideration of economy and heat exchange efficiency, a high-efficiency plate-and-frame heat exchanger is preferred. The heat exchange equipment adopts corresponding heat preservation measures to avoid heat loss. Because the fluids at the hot end and the cold end almost do not contain corrosive and highly-scaling desulfurization wastewater, the heat exchange equipment and the pump do not need to be prepared by anticorrosive and anti-scaling precious metals, and the engineering requirements can be met by preparing common metal materials with better heat conductivity.
And corresponding thermometers, pressure gauges and flow meters are arranged at the hot end fluid inlets and the cold end fluid inlets of the heat exchange equipment so as to detect the operation condition of the heat exchange equipment in real time.
Through controlling the heat exchange equipment, the temperature of the pure water-containing capric acid emulsion is reduced to about 38 ℃, the substantially water-free capric acid solution is heated to about 85 ℃, and more than 80% of heat energy can be recovered.
Example five:
as shown in fig. 7, in this embodiment, optionally, a decanoic acid emulsion tank is further provided, which is disposed at the outlet of the first separator, and is used for accommodating decanoic acid emulsion separated by the first separator. Wherein the first separator is a gravity separator and the second separator is a centrifugal separator.
The top end of the heater of the embodiment is provided with an overflow pipeline, and heated decanoic acid flows into the mixer through the overflow pipeline. The mixed emulsion is formed after being fully mixed by the mixer, and the mixed emulsion overflows to the first separator from the center of the top of the gravity separator. The first separator is a gravity separator, the concentrated solution of the desulfurization wastewater which is siphoned and separated from the bottom of the first separator is treated in the next procedure, and the decanoic acid emulsion which overflows from the first separator overflows to a decanoic acid emulsion box. The outlet of the decanoic acid emulsion tank is provided with a pump which conveys the decanoic acid emulsion to the hot end of the radiator, and the decanoic acid emulsion is conveyed to the bottom of the first cooler after being cooled by the hot end. The top of the first cooler is provided with an overflow pipeline, part of water is separated out from the cooled decanoic acid emulsion to form a mixture of water and decanoic acid solution, and the mixture overflows to the second separator through the overflow pipeline for further separation.
The decanoic acid solution separated by the second separator is conveyed to a decanoic acid solution tank, then conveyed to the cold end of the radiator through the pump, subjected to heat exchange with heat released in the cooling process of the decanoic acid emulsion, heated and conveyed to the heater, and part of system heat can be recovered. And conveying the produced water separated by the second separator to a water production tank, and further conveying the produced water to a second cooler for further cooling so as to completely solidify and separate out trace decanoic acid in the produced water, and then separating decanoic acid solid from pure water through a filter. The separated solid decanoic acid is sent to a heater for recycling, and the separated pure water can be used for other industrial purposes.
Example six:
the desulfurization wastewater concentration method of the embodiment adopts the system of the first embodiment, and comprises the following four steps:
1) heating decanoic acid in a container to a set temperature to keep the decanoic acid in a liquid state, wherein the melting point of the decanoic acid is 31.5 ℃, the boiling point of the decanoic acid is 270 ℃, and controlling the temperature of the mixed solution to be less than or equal to 95 ℃ through thermodynamic equilibrium calculation so as to avoid the vaporization and evaporation of the desulfurization wastewater, so that the set temperature is preferably 31.5-95 ℃. The heating container should take external thermal insulation measures to avoid heat loss.
The heating source of the decanoic acid is not limited, and can be electric power, steam, hot flue gas, hot water or other waste heat sources from a coal-fired power plant, and can also be combustible fuels such as solar energy, geothermal energy, or natural gas, diesel oil and the like. However, for coal fired power plants, hot flue gas, hot water, or other waste heat sources may be economical heat sources.
The heating method is not limited, and direct heating can be adopted according to the heating heat source, such as: the decanoic acid can be directly heated by the heating part through electric power, steam, hot flue gas, hot water, geothermal heat and the like; indirect heating may also be used, such as: the solar energy, or combustible fuels such as natural gas, diesel oil and the like can be deionized water as a heat transfer medium, a heat source directly heats the deionized water through a heating part, and the heated deionized water heats the decanoic acid through a heat exchange part.
2) Adding the pretreated desulfurization wastewater into the heated capric acid, fully stirring and mixing, continuously heating and maintaining the set temperature for 1-5min, and taking external heat preservation measures in the mixing container to uniformly stir so as to saturate the water dissolved and absorbed in the capric acid solution to form mixed emulsion in order to avoid heat loss. In the mixed emulsion, the desulfurization wastewater pretreatment water is concentrated by being dissolved and absorbed into the capric acid.
In the decanoic acid solution, the smaller the particle size of the liquid drop of water is, the larger the specific surface area is, the more favorable the dissolution, absorption and mass transfer of water in the decanoic acid solution are, and experimental researches show that: the droplet size of the water is reasonably controlled to be 90-110 μm, and the water dissolved in the decanoic acid solution can reach saturation within 1 min.
3) Separating the mixed emulsion to separate out decanoic acid emulsion and desulfurization wastewater concentrated solution; and carrying out end solidification treatment on the separated desulfurization wastewater concentrated solution.
There are various methods for separating the decanoic acid emulsion containing pure water from the desulfurized wastewater concentrate, including but not limited to: gravity separation, centrifugal separation, electrophoretic separation or cyclone separation.
By controlling the residence time of the mixed emulsion in the separator to be greater than the settling time of the concentrated droplets of the desulfurization wastewater, it was found that gravity separation was sufficient to achieve separation of the concentrated desulfurization wastewater from the solution of capric acid containing pure water. Compared with other separation modes, the device has the advantages that the device is simple in structure and free of energy consumption based on gravity separation of density difference between the pure water-containing decanoic acid emulsion and the desulfurization wastewater concentrated solution.
The retention time of the mixed emulsion in the separator is controlled to be more than 20min, and separation of more than 95% of the desulfurization waste water concentrated solution and the pure water-containing decanoic acid solution can be realized through gravity separation. In the actual engineering, the retention time of the mixed emulsion in the separator is more than or equal to 30min, the complete separation of the concentrated solution of the desulfurization wastewater and the capric acid emulsion containing pure water can be realized, and the engineering requirements can be completely met.
4) Cooling the separated decanoic acid emulsion to 32-40 ℃ to separate out part of water from the decanoic acid emulsion to form decanoic acid solution and water; returning the decanoic acid solution to the step 1) for recycling.
There are various methods for separating the decanoic acid solution from water, including but not limited to: gravity separation, centrifugal separation, electro-coagulation separation or cyclone separation. Experimental research shows that: the water drops precipitated from the capric acid emulsion have a particle size range of 1-30 μm, wherein the proportion of pure water drops larger than 5 μm is larger than 95%. Such fine droplets, gravity separation requires considerable settling time; and the engineering application of the electro-concentration separation or the cyclone separation is also very difficult. Therefore, in this embodiment, centrifugal separation is preferred, and the whole decanoic acid emulsion can be separated by the residence time in the centrifugal separator being more than 15 seconds. In actual engineering, the retention time of the decanoic acid emulsion in the centrifugal separator is more than or equal to 30s, the decanoic acid and water can be almost completely separated, and the engineering requirements can be met.
The heat exchange can be carried out by taking the decanoic acid emulsion containing pure water as a hot end and taking the recycled decanoic acid solution which does not contain water basically as a cold end through heat exchange equipment. The reclaimed capric acid solution which is basically free of water is heated by the heat released in the cooling process of the capric acid emulsion containing pure water, so that the heat can be well recovered, the energy consumption is reduced, and the efficiency is improved.
The desulfurization wastewater concentration method does not need to soften the desulfurization wastewater, and does not need to invest and construct large-scale softening process equipment for the desulfurization wastewater rich in high-concentration scale-causing ions; a large amount of chemical softening agents are not required to be added; a large amount of softened sludge does not need to be treated; the investment of softening equipment and structures, the cost of softening agents and softening sludge and the operation and maintenance cost of the softening equipment are saved.
Compared with the prior various hot method and membrane method concentration processes, the desulfurization wastewater concentration method is not limited by the salt content of the desulfurization wastewater, can be widely applied to the concentration of the desulfurization wastewater with various salt contents, and can concentrate the desulfurization wastewater to an extremely high concentration close to salinity saturation, namely, salt is not crystallized and separated out.
Compared with the prior various thermal method and membrane method concentration processes, the desulfurization wastewater concentration method can operate in a wider temperature range, can fully utilize various low-grade waste heat of a coal-fired power plant as heat sources, has a heat recovery rate of over 80 percent, and reduces energy consumption.
Compared with the prior various hot method and membrane method concentration processes, the desulfurization wastewater concentration method provided by the invention has the advantages that the heated, heat-exchanged and cooled fluid does not contain strong corrosive and high scaling substances basically, so that the heating, heat-exchanging and cooling equipment does not need to be cleaned regularly, expensive anti-corrosion and anti-scaling materials are not needed for preparation, the equipment investment can be greatly reduced, and the operation cost can be greatly reduced.
Compared with various existing hot method and membrane method concentration processes, the desulfurization wastewater concentration method provided by the invention has the advantages that the produced water is basically pure water without salt, and the produced water is convenient to recycle for other purposes.
Example seven:
in this embodiment, on the basis of the fifth embodiment, in the step 4), the water precipitated from the decanoic acid emulsion is cooled to 5-31.5 ℃, that is, the decanoic acid is below the melting point and above the melting point, so that trace amount of decanoic acid contained in the water is generated into white crystals, and pure water and solid decanoic acid are separated by filtration; sending the separated decanoic acid crystals to the step 1) for recycling.
For most areas, natural cooling can be adopted, and trace amount of capric acid contained in the produced water is removed by filtration. For some areas, especially in hot summer, natural cooling often cannot meet engineering requirements, an open mechanical ventilation cooling tower is adopted for forced cooling, trace decanoic acid contained in produced pure water is filtered and removed, and special design and manufacturing are carried out according to specific engineering.
By the mode, trace decanoic acid in water can be completely removed to obtain pure water, and the pure water is convenient to be subsequently used in other industrial production.
Claims (16)
1. The utility model provides a concentrated system of desulfurization waste water based on capric acid extraction which characterized in that: comprises a heater, a mixer, a delivery pump, a first separator, a capric acid solution tank, a water production tank, a second separator and a first cooler; the outlet of the heater and the outlet of the conveying pump are respectively connected with the inlet of the mixer, and the outlet of the mixer is connected with the inlet of the first separator; the first separator is sequentially connected with the first cooler and the second separator; one outlet of the second separator is connected with a decanoic acid solution tank, and is connected to the inlet of the heater through the decanoic acid solution tank, and the other outlet of the second separator is connected with a water production tank; mixing capric acid and desulfurization wastewater in a mixer to form mixed emulsion, and separating aqueous capric acid emulsion and desulfurization wastewater concentrated solution by a first separator; after passing through a first cooler, the aqueous capric acid emulsion enters a second separator to separate a capric acid solution and water; sending the decanoic acid solution into a decanoic acid solution tank, and then conveying the decanoic acid solution to a heater for recycling; the water separated by the second separator is discharged into a water production tank.
2. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 1, characterized in that: still include the venturi ejector, the delivery pump exit linkage venturi ejector entry, venturi ejector exit linkage blender entry, desulfurization waste water enters into the blender through the venturi ejector injection.
3. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 2, characterized in that: the second cooler and the filter are sequentially connected to the outlet of the water production tank; and water separated out by the second separator enters a second cooler for cooling after passing through a water production tank, so that the decanoic acid in the water is crystallized, the water is separated from the decanoic acid solid through a filter, and the separated decanoic acid solid is sent to a heater for recycling.
4. The decanoic acid extraction-based desulfurization wastewater concentration system according to any one of claims 1 to 2, characterized in that: a heat exchanger is arranged between the first separator and the first cooler, the decanoic acid emulsion separated by the first separator flows into the decanoic acid emulsion box and then is input into the hot end of the heat exchanger through a pump, and the decanoic acid emulsion after heat release enters the first cooler; the decanoic acid solution separated by the second separator enters a decanoic acid solution tank, then is input into the cold end of the heat exchanger through a pump, and the decanoic acid solution after heat absorption is sent into the heater.
5. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 4, characterized in that: the first separator adopts a gravity separator; the second separator is a centrifugal separator.
6. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 5, characterized in that: the gravity separator is in a cone frustum shape with a large upper part and a small lower part, and a perforated plate is arranged on the central plane in the gravity separator; a mixed emulsion input pipe is arranged at the center of the gravity separator, the outlet of the mixed emulsion input pipe is positioned at the lower side of the porous plate, and the mixed emulsion is conveyed to the lower side of the porous plate through the mixed emulsion input pipe; the top of the gravity separator is provided with a capric acid overflow outlet pipe, and the bottom is provided with a desulfurization wastewater concentrated solution siphon outlet pipe.
7. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 6, characterized in that: a temperature sensor is arranged in the mixer; the lower part of the mixer is conical, and the upper part of the mixer is cylindrical; a decanoic acid inlet pipe is arranged in the middle of the lower cone of the mixer, heated decanoic acid overflows into the mixer from the tangential direction along the circumference through the decanoic acid inlet pipe, and the flow direction of the fluid is in the same direction as the stirring rotation direction; a desulfurization waste water inlet pipe is arranged at the center of the bottom of the lower cone of the mixer, and desulfurization waste water enters the mixer from the desulfurization waste water inlet pipe after being pressurized by the delivery pump; the top of the mixer is provided with a mixed emulsion self-overflow pipe, and the mixed emulsion is discharged from the overflow pipe through the mixed emulsion.
8. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 7, characterized in that: the heat exchanger is a jacketed heat exchanger, an immersed coil heat exchanger, a plate-frame heat exchanger or a shell-and-tube heat exchanger; the hot end and the cold end inlets of the heat exchanger are provided with a thermometer, a pressure gauge or a flowmeter.
9. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 8, characterized in that: the first cooler is a natural cooling pond or an open mechanical ventilation cooling tower; the first cooler is provided with a temperature sensor or a temperature measuring instrument.
10. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 3, characterized in that: a heat exchanger is arranged between the first separator and the first cooler, the decanoic acid emulsion separated by the first separator flows into the decanoic acid emulsion box and then is input into the hot end of the heat exchanger through a pump, and the decanoic acid emulsion after heat release enters the first cooler; the decanoic acid solution separated by the second separator enters a decanoic acid solution tank, then is input into the cold end of the heat exchanger through a pump, and the decanoic acid solution after heat absorption is sent into the heater.
11. The decanoic acid extraction-based desulfurization wastewater concentration system according to claim 10, characterized in that: the first separator adopts a gravity separator; the second separator is a centrifugal separator.
12. The decanoic acid extraction-based desulfurization wastewater concentration system of claim 11, wherein: the gravity separator is in a cone frustum shape with a large upper part and a small lower part, and a perforated plate is arranged on the central plane in the gravity separator; a mixed emulsion input pipe is arranged at the center of the gravity separator, the outlet of the mixed emulsion input pipe is positioned at the lower side of the porous plate, and the mixed emulsion is conveyed to the lower side of the porous plate through the mixed emulsion input pipe; the top of the gravity separator is provided with a capric acid overflow outlet pipe, and the bottom is provided with a desulfurization wastewater concentrated solution siphon outlet pipe.
13. The decanoic acid extraction-based desulfurization wastewater concentration system of claim 12, wherein: a temperature sensor is arranged in the mixer; the lower part of the mixer is conical, and the upper part of the mixer is cylindrical; a decanoic acid inlet pipe is arranged in the middle of the lower cone of the mixer, heated decanoic acid overflows into the mixer from the tangential direction along the circumference through the decanoic acid inlet pipe, and the flow direction of the fluid is in the same direction as the stirring rotation direction; a desulfurization waste water inlet pipe is arranged at the center of the bottom of the lower cone of the mixer, and desulfurization waste water enters the mixer from the desulfurization waste water inlet pipe after being pressurized by the delivery pump; the top of the mixer is provided with a mixed emulsion self-overflow pipe, and the mixed emulsion is discharged from the overflow pipe through the mixed emulsion.
14. The decanoic acid extraction-based desulfurization wastewater concentration system of claim 13, wherein: the heat exchanger is a jacketed heat exchanger, an immersed coil heat exchanger, a plate-frame heat exchanger or a shell-and-tube heat exchanger; the hot end and the cold end inlets of the heat exchanger are provided with a thermometer, a pressure gauge or a flowmeter.
15. The decanoic acid extraction-based desulfurization wastewater concentration system of claim 14, wherein: the first cooler is a natural cooling pond or an open mechanical ventilation cooling tower; the first cooler is provided with a temperature sensor or a temperature measuring instrument.
16. The decanoic acid extraction-based desulfurization wastewater concentration system of claim 15, wherein: the second separator is provided with a temperature sensor or a temperature measuring instrument; the second cooler is a natural cooling pond or an open mechanical ventilation cooling tower.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111908547A (en) * | 2020-09-03 | 2020-11-10 | 国电科学技术研究院有限公司 | Method and system for concentrating desulfurization wastewater based on capric acid extraction |
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Address after: 210046 fairyland Road, Qixia District, Nanjing, Jiangsu Province, No. 10 Patentee after: National Energy Group Science and Technology Research Institute Co.,Ltd. Patentee after: GUODIAN NANJING ELECTRIC POWER TEST RESEARCH Co.,Ltd. Address before: 210046 fairyland Road, Qixia District, Nanjing, Jiangsu Province, No. 10 Patentee before: GUODIAN SCIENCE AND TECHNOLOGY RESEARCH INSTITUTE Co.,Ltd. Patentee before: GUODIAN NANJING ELECTRIC POWER TEST RESEARCH Co.,Ltd. |