KR101397068B1 - Apparatus for waste heat recovery and abatement of white plume of exhaust gas with reusable of wastewater - Google Patents

Abstract

The present invention rescues latent heat and moisture contained in exhaust gas through a solution containing hygroscopic salts to reduce white smoke, filters a solution containing hygroscopic salts to remove contaminants contained in the exhaust gas, The present invention relates to a waste heat recovery and white smoke reduction apparatus for recovering waste water from a waste gas and recovering salts and reusing the waste water. A moisture-absorbing salt solution tank into which the hygroscopic salt solution brought into contact with the exhaust gas flows, and a moisture-absorbing salt solution tank of the hygroscopic salt solution tank A first heat exchanger for heat-exchanging the solution and the circulating water to heat the circulating water; A filter for removing contaminants contained in the hygroscopic salt solution of the liquid bath and a concentrated water treatment device for separating the raw water of the first treated water tank containing the reverse water of the filter into concentrated water with concentrated pure water and hygroscopic salts, And the concentrated water separated by the concentrated water treatment apparatus is supplied to the hygroscopic salt solution tank.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an exhaust gas recycling apparatus and an exhaust gas recycling apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a waste heat recovery apparatus and a white smoke reduction apparatus for recovering waste heat of an exhaust gas and a white smoke reduction apparatus, The present invention relates to a waste heat recovery apparatus and a white smoke reduction apparatus for recovering waste water that can be reused by collecting hygroscopic salts and removing the pollutants contained in the exhaust gas by filtering the solution.

An incinerator, a metal melting furnace, a boiler, a wet desulfurization facility, etc. generate exhaust gas containing a high concentration of pollutants. In order to remove pollutants contained in the exhaust gas, an absorption tower or a wet type dust collector is generally used. The wet type dust collector is a device for removing contaminants in the exhaust gas by spraying water to a high temperature exhaust gas. The exhaust gas discharged from the wet type dust collector is discharged to the atmosphere through the stack by the high temperature and high humidity state.

The exhaust gas discharged through the stack is in the form of white smoke, which is white smoke because it contains saturated water. The white smoke discharged through the stack is usually at a temperature of 60 to 200 캜. When the air comes in contact with the cold air outside the stack, the saturated water in the white smoke condenses and falls. Since the white smoke contains various contaminants, the condensed and falling water contains a large amount of harmful substances to the human body.

As a method for preventing such white smoke, a method of mixing the high temperature air to reduce the relative humidity of the exhaust gas or directly heating the exhaust gas by providing a burner on the stack is applied. However, in the former case, installation cost is very high, and in the latter case, maintenance cost due to fuel consumption is high.

In addition, a number of patent documents including Patent Document 1 (Korean Patent No. 10-1200330) and Patent Document 2 (Korean Patent No. 10-375555) have been proposed as methods for reducing white smoke. However, these patented technologies not only include complicated equipment (wet type dust collecting device) and the like as described above, but also are not effective in reducing white smoke. Patent Document 3 (Korean Patent No. 10-949853) discloses a technique of reducing white smoke by lowering the temperature of white smoke through a heat exchanger, but there is a limit in removing pollutants contained in white smoke. In addition, conventional technologies have focused on reducing white smoke, which is insufficient to recycle heat contained in white smoke.

On the other hand, if we look at the physical characteristics of the humid exhaust gas using the psychrometric chart, it can be seen that, depending on the tx line (t: temperature, x: absolute humidity) with the dry bulb temperature and absolute humidity as coordinates, It is known that the absolute humidity increases along a steep rising curve in the range of 60 to 70 ° C and the absolute humidity is also increased by the minute temperature difference near the vertical in the temperature range of 70 ° C or more . Therefore, it is necessary to control the temperature and humidity of the exhaust gas discharged from the incinerator or the like to an appropriate level (outlet temperature 60 ° C or less, absolute humidity 40 or less).

Korean Patent No. 10-1200330 Korean Patent No. 10-375555 Korean Patent No. 10-949853

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a method of recovering latent heat and moisture contained in exhaust gas through a solution containing hygroscopic salts, And to provide a device for recovering and reducing white smoke.

The present invention also relates to a waste heat recovery apparatus for recovering waste water and a white smoke reducing apparatus capable of recovering hygroscopic salts and reusing concentrated water by filtrating a solution containing hygroscopic salts to remove pollutants contained in the exhaust gas There are other purposes to provide.

In order to accomplish the above object, the present invention provides a waste heat recovery and white smoke reduction apparatus for exhaust gas recycling capable of reusing concentrated water, comprising: a recovery unit for recovering moisture and latent heat of an exhaust gas by contacting a hygroscopic salt solution with exhaust gas, A first heat exchanger for heating the circulating water by exchanging heat between the hygroscopic salt solution of the hygroscopic salt solution tank and the circulating water, and a hygroscopic salt solution tank for absorbing the hygroscopic salt solution, A filter for removing contaminants contained in the hygroscopic salt solution of the salt solution tank, and a concentrated water treatment apparatus for separating the raw water of the first treated water tank containing the reverse water of the filter into concentrated water with concentrated hygroscopic salts And the concentrated water separated by the concentrated water treatment apparatus is supplied to the hygroscopic salt solution tank It shall be.

Wherein the pretreatment filtration membrane is composed of a pretreatment filtration membrane and a hygroscopic salt separation membrane or is composed of a pretreatment filtration membrane and an evaporation concentrator or comprises a pretreatment filtration membrane, a hygroscopic salt separation membrane and an evaporation concentrator, Wherein at least one of the hygroscopic salt separation membrane and the evaporation concentrator separates the treated water of the pretreatment filtration membrane into pure water and concentrated water in which hygroscopic salts are concentrated and the concentrated water is separated into the hygroscopic salt solution tank Lt; / RTI > The hygroscopic salt separation membrane may be composed of any one of a reverse osmosis membrane, a vibration membrane, and a spiral membrane.

And a third heat exchanger for contacting the hygroscopic salt solution of the hygroscopic salt solution tank with another circulating water to heat the circulating water and supplying the cooled hygroscopic salt solution to the filter. Further, a second heat exchanger for heating the circulating water heated by the first heat exchanger using water vapor separated from the hygroscopic salt solution of the hygroscopic salt solution tank, and a phase separator, wherein the phase separator comprises a hygroscopic salt of a hygroscopic salt solution tank The steam is separated from the solution and supplied to the second heat exchanger, and the condensed water of the steam formed in the second heat exchanger is transferred to the first treated water tank.

A hygroscopic salt solution supply nozzle for supplying a hygroscopic salt solution to the upper end of the heat-water exchange apparatus is provided, and the hygroscopic salt solution cooled by the first heat exchanger is supplied to the hygroscopic salt solution supply nozzle . Further, an air ejector may be further provided to supply the low-temperature, high-pressure air to one side of the heat-water exchanger, into the heat-moisture exchanger to induce condensation of the exhaust gas.

A rare-earth ball layer may be provided in the inside of the heat-water exchange apparatus to primarily contact the exhaust gas to adsorb contaminants in the exhaust gas and to decompose organic matter. The hygroscopic salt solution is an aqueous solution with a hygroscopic salt dissolved, the hygroscopic salts of calcium nitrate hydrate, ammonium nitrate (NH ₄ NO _3), ammonium sulfate _{((NH 4) 2 SO 3} ), perchloric acid barium (Ba (CIO ₄ ) _2), potassium bicarbonate (KHCO _3), sodium nitrate (NaNO _3), sodium chlorite (NAClO _3), potassium nitrate (KNO _3), barium nitrate, can be sodium perchlorate, sodium chloride, calcium chloride, formic any one of potassium have.

The concentration of the hygroscopic salt solution is adjusted to 40 to 80 wt%.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of an apparatus for recovering waste heat and an apparatus for reducing the amount of white smoke in exhaust gas which can be reused in concentrated water according to an embodiment of the present invention. FIG.

The present invention proposes a technique for adsorbing pollutants of exhaust gas through a hygroscopic salt solution and collecting moisture and latent heat of the exhaust gas. The present invention provides a technique for maintaining the concentration of the hygroscopic salt solution constant, And to optimize the pollutant adsorption properties. The present invention also provides a technique for removing contaminants in a hygroscopic salt solution through a filtration process and collecting and reusing hygroscopic salts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus for recovering waste heat of exhaust gas and recovering white smoke according to an embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, an apparatus for recovering waste heat and reducing white smoke of exhaust gas, which can be reused with concentrated water, according to an embodiment of the present invention includes a heat-moisture exchanger 110, a hygroscopic salt solution tank 120, And a hygroscopic salt recovery apparatus.

The heat-water exchanger 110 recovers latent heat of pollutants and exhaust gases contained in the exhaust gas. A hygroscopic salt solution supply nozzle 112 for spraying a hygroscopic salt solution is provided at the upper end of the heat-water exchange apparatus 110, and a rare-earth ball layer is provided in the heat-water exchange apparatus 110.

The hygroscopic salt solution is a solution containing hygroscopic salts, absorbing and absorbing latent heat and moisture of the exhaust gas, and adsorbing contaminants contained in the exhaust gas. As the hygroscopic salts soluble in the hygroscopic salt solution, calcium nitrate hydrate (Ca (NO ₃ ) ₄ .H ₂ O) may be used. Calcium nitrate hydrate has excellent adsorption properties of pollutants and has high solubility and high solubility according to temperature, and recovery is easy at low temperature. In addition, the calcium nitrate hydrate has an endothermic reaction upon dissolution and is excellent in the latent heat recovery characteristic of the exhaust gas.
(NH ₄ NO ₂ ), ammonium sulfate ((NH ₄ ) ₂ SO ₃ ), barium perchlorate (Ba (CIO ₄ ) ₂ ), and calcium nitrate hydrate are used as the hygroscopic salts, Any one of potassium hydrogencarbonate (KHCO ₃ ), sodium nitrate (NaNO ₃ ), sodium chlorate (NAClO ₃ ), potassium nitrate (KNO ₃ ), barium nitrate, sodium perchlorate, sodium chloride, calcium chloride and potassium formate may be used.

On the other hand, when the calcium nitrate hydrate aqueous solution is used as the hygroscopic salt solution, the concentration of the aqueous solution of calcium nitrate hydrate is preferably adjusted to 40 to 80 wt% in order to maximize the latent heat recovery and the water absorption characteristics. If the concentration of the hygroscopic salts is less than 40 wt%, the water absorption rate is lowered. If the concentration of the hygroscopic salts exceeds 80 wt%, the hygroscopic salts tend to settle or solidify. At this time, there is a difference in absorption rate depending on the type of hygroscopic salts, and it is necessary to selectively control the concentration of hygroscopic salts in consideration of this. In the heat-water exchanger 110, the exhaust gas and the hygroscopic salt solution preferably contact with each other at a weight ratio of 1: 2 to 10, and the contact time should be maintained for at least one second.

The rare earth ball layer is an aggregate of rare earth balls, which adsorbs contaminants in the exhaust gas when the exhaust gas is permeated, and generates anions to decompose the organic substances contained in the exhaust gas. The rare earth ball is a ceramic carrier containing a rare earth element. Examples of the rare earth element include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, Europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, Yttrium, and silicon oxide (SiO ₂ ) may be used as the ceramic carrier containing the rare earth elements. The rare earths may be contained in the ceramic carrier in an amount of 0.1 to 0.5 wt%.

When the exhaust gas is supplied through the lower part of the heat-water exchanger 110, the exhaust gas is in contact with the rare-earth ball layer, and the contaminants in the exhaust gas are primarily removed by contact with the rare- The organic matter is decomposed by the rare earth ball layer. The exhaust gas passing through the rare earth ball layer is brought into contact with the hygroscopic salt solution sprayed from the hygroscopic salt solution spray nozzle. The latent heat of the pollutants and the exhaust gas in the exhaust gas is absorbed by the hygroscopic salt solution, - Moving to the hygroscopic salt solution tank (120) connected to one side of the water exchanger (110). Further, the exhaust gas from which latent heat and contaminants are removed is transferred to the stack 40 and discharged to the outside. The hygroscopic salt solution spray nozzle may be designed to spray the hygroscopic salt solution in a vortex shape in order to increase the contact efficiency between the hygroscopic salt solution and the exhaust gas.

Meanwhile, an air ejector may be further provided on one side of the heat-water exchanger 110 to double the latent heat of the exhaust gas. The air ejector is disposed between the hygroscopic salt solution supply nozzle 112 and the rare earth ball layer or below the rare earth ball layer to inject low temperature and high pressure air into the heat- And is in contact with the air to accelerate the condensation of the exhaust gas.

The hygroscopic salt solution tank 120 is a reservoir for the hygroscopic salt solution, and the hygroscopic salt solution falling down from the inside of the heat-moisture exchanger 110 flows into the hygroscopic salt solution tank 120. Since the hygroscopic salt solution introduced from the heat-water exchanger 110 absorbs the latent heat of the exhaust gas, the temperature in the hygroscopic salt solution tank 120 maintains a high temperature state. In addition, since the contaminants are adsorbed in the hygroscopic salt solution introduced from the heat-water exchange apparatus 110, the contaminants such as dust are contained in the hygroscopic salt solution tank 120, It is naturally settled to the lower part of the hygroscopic salt solution tank 120, and a part thereof floats.

The hygroscopic salt solution in the hygroscopic salt solution tank 120 is used for heat exchange and is supplied to the heat-water exchanger 110 again. To this end, the first to third heat exchangers 130 and 140 150 are provided.

One end of the first heat exchanger 130 is connected to the hygroscopic salt solution supply line 10 and the other end is connected to the circulation water supply line 20. The hygroscopic salt solution in the hygroscopic salt solution tank 120 is supplied to the hygroscopic salt solution supply line 10 through a pump, and the circulation water of the circulation water supply line 20 corresponds to the amount of heat . The circulating water supply line 20 extends to a discharge end of the second heat exchanger 140 via a second heat exchanger 140 to be described later and the hygroscopic salt solution supply line 10 is connected to the first heat exchanger 130 to the hygroscopic salt solution supply nozzle 112.

In the first heat exchanger 130, a hygroscopic salt solution supply line 10 and a circulation water supply line 20 are provided so as to cross each other, whereby the heat of the hygroscopic salt solution is transferred to the circulation water, And is discharged through one side of the first heat exchanger (130). On the other hand, the hygroscopic salt solution which has lost heat to the circulating water is transferred to the hygroscopic salt solution supply nozzle 112 along the extended hygroscopic salt solution supply line 10 to be reused for the latent heat recovery of the exhaust gas and the adsorption of pollutants do.

The second heat exchanger 140 further heats the circulating water heated through the first heat exchanger 130 through the hygroscopic salt solution of the hygroscopic salt solution tank 120. One end of the second heat exchanger 140 is connected to the circulating water supply line 20 extending from the first heat exchanger 130 and the other end of the second heat exchanger 140 is connected to the phase separator phase separator (170). The phase separator 170 separates the hygroscopic salt solution at a high temperature in the hygroscopic salt solution tank 120 into water vapor and liquid. The separated water vapor passes through the water vapor discharge end And then flows into the second heat exchanger 140 along the steam supply line. At this time, the phase separator 170 can separate the hygroscopic salt solution into water vapor and liquid by heating the hygroscopic salt solution.

A circulation water supply line 20 and a steam supply line 31 are provided in the second heat exchanger 140 in an intersecting manner and the circulating water of the circulation water supply line 20, And is further heated by the steam of the supply line 31. The circulating water additionally heated by the steam can be moved along the extended circulating water supply line 20 and used as heating water or the like. The condensed water is moved to the first treated water tank 181 along the condensed water discharge line 31. The condensed water discharged through the condensed water discharge line 31 flows into the first treated water tank 181, For reference, the condensed water discharge line 30 extends from the water vapor supply line 31.

On the other hand, as described above, since the contaminants are adsorbed in the hygroscopic salt solution flowing from the heat-moisture exchanger 110, the concentration of the contaminant increases in the hygroscopic salt solution tank 120 with time. The contaminants in the hygroscopic salt solution tank 120 are naturally sedimented to form a sludge, and the sludge is moved to the sludge storage tank and is treated through drawing or the like. The bottom of the hygroscopic saline solution tank 120 may be inclined for movement to the sludge storage tank.

A vortex filter 160 is provided to remove contaminants floating in the hygroscopic salt solution tank 120. The vortex filter 160 forms a vortex in the hygroscopic salt solution flowing into the vortex filter 160 to remove contaminants contained in the hygroscopic salt solution. At this time, if the high-temperature hygroscopic salt solution immediately flows into the vortex filter 160, there is a possibility that the vortex filter 160 may be damaged due to the high temperature. To prevent this, the third heat exchanger 150 are provided.

One end of the third heat exchanger 150 is connected to the hygroscopic salt solution supply line 11 separate from the hygroscopic salt solution supply line 10 and the other end is connected to the circulation water supply line 20, And the circulating water is heated by the high-hygroscopic salt solution. The hygroscopic salt solution, which has lost heat, flows into the vortex filter 160. The vortex filter 160 filters pollutants contained in the introduced hygroscopic salt solution, and the filtered hygroscopic salt solution is directly transferred to the hygroscopic salt solution tank 120, or is transferred to the hygroscopic salt solution tank 120 via the phase separator 170. [ (120). In addition, the treated water of the vortex filter 160 is transferred to the first treated water tank 181. The vortex filter 160 is provided with a silica filtration agent and can be cleaned by backwashing, and the backwash water of the vortex filter 160 is transferred to the first treatment water tank 181.

Condensation water in which water vapor of the hygroscopic salt solution is condensed and backwash water of the vortex filter 160 are stored in the first treated water tank 181. The condensed water and the reverse water contain a very small amount of hygroscopic salts, The amount of the hygroscopic salt solution in the hygroscopic salt solution tank 120 is decreased as the amount of the stored water in the first treatment tank 181 is increased and the concentration of the hygroscopic salt solution in the hygroscopic salt solution tank 120 is kept constant. It is inevitably required to supply additional hygroscopic salts. To solve this problem, the above-described concentrated water treatment apparatus is provided.

The concentrated water treatment apparatus separates the condensed water and the reverse water in the first treated water tank 181 into pure water and concentrated water finally and collects the concentrated water containing the hygroscopic salts in the hygroscopic salt solution tank 120, So that the hygroscopic salt concentration of the hygroscopic salt solution tank 120 is kept constant.

The concentrated water treatment apparatus includes a pretreatment filtration membrane 191 and a hygroscopic salt separation membrane 192 in detail. The pretreatment filtration membrane 191 serves to separate the raw water in the first treated water tank 181 into wastewater and treated water. The separated treated water is transferred to the second treated water tank 182, . The floating substances not filtered by the vortex filter 160 are removed by the pretreatment filtration membrane 191 but the hygroscopic salts are not separated by the pretreatment filtration membrane 191 but are contained in the treatment water, 182, respectively. As the pretreatment filtration membrane 191, an ultrafiltration membrane may be used.

The hygroscopic salt separation membrane (192) serves to separate the treated water of the pretreatment filtration membrane (191) into pure water and concentrated water in which hygroscopic salts are concentrated. The hygroscopic salt separation membrane (192) may be composed of a reverse osmosis membrane capable of separating salts, and a diaphragm membrane or a spiral membrane may be applied. The concentrated water concentrated by the hygroscopic salt separation membrane 192 is returned to the hygroscopic salt solution tank 120 so that the concentration of the hygroscopic salts of the hygroscopic salt solution tank 120 can be maintained constant. The pure water separated by the hygroscopic salt separation membrane (192) can be utilized as reused water.

It is also possible to apply the evaporation concentrator 194 instead of the hygroscopic salt separation membrane 192. The evaporation concentrator 194 serves to heat the treated water of the pretreatment filtration membrane 191 and separate it into evaporated water and concentrated water. Heat required for the evaporation concentrator 194 can be obtained from waste heat, The evaporation process can be performed to lower the evaporation temperature. That is, the evaporation concentrator 194 may be constituted by a reduced pressure evaporation concentrator. It is also possible to apply the evaporation concentrator 194 and the hygroscopic salt separation membrane 192 simultaneously. In this case, the treated water of the pretreatment filtration membrane 191 is distributed and treated in the evaporation concentrator 194 and the hygroscopic salt separation membrane 192, and the concentrated water separated by the evaporation concentrator 194 and the hygroscopic salt separation membrane 192 , And the concentrated water in which the hygroscopic salts are concentrated is returned to the hygroscopic salt solution tank (120). The reverse water of the evaporation concentrator 194 and the hygroscopic salt separation membrane 192 is transferred to the first treatment water tank 181 so that the above-described concentrated water separation process can be reapplied.

In order to prevent a scale from being formed in the pretreatment filtration membrane 191 and the hygroscopic salt separation membrane 192, a scale inhibitor supplying a scale inhibitor to the pretreatment filtration membrane 191 and the hygroscopic salt separation membrane 192 An apparatus 193 may be further provided.

As described above, the waste heat recovery and the white smoke reduction apparatus of the exhaust gas which can be reused in the concentrated water according to the embodiment of the present invention has been described. Next, the operation of the waste heat recovery and the white smoke reduction device of the exhaust gas that can be reused in the concentrated water according to the embodiment of the present invention will be described.

The exhaust gas generated in the incineration plant, the power plant, and the like is supplied to the heat-water exchanger 110 before being moved to the stack. The exhaust gas supplied into the heat-water exchanger 110 comes into contact with the rare-earth ball layer in the heat-water exchanger 110 to primarily remove contaminants and decompose organic matter. The exhaust gas passing through the rare earth ball layer is brought into contact with the hygroscopic salt solution sprayed from the hygroscopic salt solution supply nozzle, whereby the latent heat of the exhaust gas and contaminants are absorbed by the hygroscopic salt solution. The hygroscopic salt solution in which the latent heat and the contaminants are absorbed falls to the bottom of the heat-water exchanger 110 and is transferred to the hygroscopic salt solution tank 120. At this time, in order to multiply the number of times of latent heat of the exhaust gas, low-temperature high-pressure air can be supplied to the inside of the heat-water exchanger 110 to come into contact with the exhaust gas. Falls. The exhaust gas of 60~200 ℃ by the same exhaust gas in contact with the hygroscopic salt solution may be adjusted to an absolute humidity less than 40 (g / m ³⁾ with a falling to a temperature below 60 ℃. In the present invention, the amount of heat recovered through the heat exchanger is large in contrast to the case of direct heat exchange of ordinary exhaust gas, because the latent heat of the exhaust gas is recovered through the hygroscopic salt solution and the hygroscopic salt solution is subjected to heat exchange Because.

The hygroscopic salt solution absorbing the latent heat of the exhaust gas is in a high temperature state, and the hygroscopic salt solution of the high temperature stored in the hygroscopic salt solution tank 120 is used for heat exchange. The hygroscopic salt solution and the circulating water flow into the first heat exchanger 130 through the separate lines 10 and 20 and the circulating water in the first heat exchanger 130 is heated by the high hygroscopic salt solution. The hygroscopic salt solution cooled by the first heat exchanger 130 is supplied to the hygroscopic salt solution supply nozzle of the heat-moisture exchanger 110, and the circulating water heated by the first heat exchanger 130 is supplied to the second heat exchanger And is further heated. In the second heat exchanger 140, water vapor is supplied through a separate supply line, and the circulation water heated by the first heat exchanger 130 is additionally heated by the steam. At this time, the water vapor supplied to the second heat exchanger 140 can be formed through phase separation of the hygroscopic salt solution. The circulating water heated by the second heat exchanger 140 is finally used as heating water or the like, and the condensed water generated by the cooling of the steam is transferred to the first treatment water tank 181.

Meanwhile, the vortex filter 160 may be used to remove contaminants from the hygroscopic salt solution tank 120, and the hygroscopic salt solution may be introduced into the vortex filter 160 to remove contaminants. At this time, the third heat exchanger 150 can be passed through to lower the temperature of the hygroscopic salt solution.

In the above description, it has been described that the concentration of the hygroscopic salt solution, that is, the aqueous solution of calcium nitrate hydrate, exhibits the optimum contaminant adsorption characteristics at 40 to 80 wt%, and the moisture in the exhaust gas is continuously supplied to the hygroscopic salt solution tank 120 The concentration of the calcium nitrate hydrate in the hygroscopic salt-containing solution tank 120 can be kept constant as a certain amount of the condensed water generated by the second heat exchanger 140 is transferred to the first treatment water tank 181. However, since the condensed water generated by the second heat exchanger 140 and the reverse water of the vortex filter 160, which are sent to the first treated water tank 181, contain a small amount of the hygroscopic salt, The continuous leakage of the wash water serves as a factor for lowering the concentration of calcium nitrate hydrate in the hygroscopic salt solution tank 120. In addition, there is a limit to the utilization of the water as the reusing water because the condensed water stored in the first treated water tank and the contaminant are contained in the contaminant.

The raw water in the first treatment water tank 181 is treated by a concentrated water treatment device to recover the hygroscopic salts and remove fine contaminants. Specifically, the raw water in the first treated water tank is removed by the pretreatment filtration membrane 191, and the treated water of the pretreatment filtration membrane 191 is purified by the hygroscopic salt separation membrane 192 or the evaporation concentrator 194, The water is separated. The concentrated water separated by the hygroscopic salt separation membrane 192 or the evaporation concentrator 194 contains concentrated hygroscopic salts at a high concentration and the concentrated water is conveyed to the hygroscopic salt solution tank 120, ) Can be kept constant.

10: Hygroscopic salt solution supply line 20: Circulating water supply line
30: water vapor supply line 40: stack
110: Heat-water exchanger
111: Rare earth ball layer 112: Hygroscopic salt solution supply nozzle
113: Air ejector 120: Hygroscopic salt solution tank
130: first heat exchanger 140: second heat exchanger
150: Third heat exchanger 160: Vortex filter
170: phase separator 181: first treatment tank
182: second treatment tank 191: pretreatment filtration membrane
192: hygroscopic salt separation membrane 193: scale inhibitor supply device
194: Evaporation concentrator

Claims (11)

A heat-moisture exchanger for contacting the hygroscopic salt solution with the exhaust gas to recover moisture and latent heat of the exhaust gas and to absorb contaminants in the exhaust gas;
A hygroscopic salt solution tank into which the hygroscopic salt solution brought into contact with the exhaust gas flows;
A first heat exchanger for heating the circulating water by exchanging heat between the hygroscopic salt solution of the hygroscopic salt solution tank and the circulating water;
A filter for removing contaminants contained in the hygroscopic salt solution of the hygroscopic salt solution tank; And
And a concentrated water treatment device for separating the raw water of the first treated water tank containing the reverse water of the filter into pure water and concentrated water concentrated hygroscopic salts,
Wherein the concentrated water separated by the concentrated water treatment device is supplied to the hygroscopic salt solution tank.
2. The apparatus according to claim 1,
A pretreatment filtration membrane and a hygroscopic salt separation membrane,
A pretreatment filtration membrane and an evaporation concentrator,
A pretreatment filtration membrane, a hygroscopic salt separation membrane, and an evaporation concentrator,
The pretreatment filtration membrane separates the raw water of the first treated water tank into wastewater and treated water, and at least one of the hygroscopic salt separation membrane and the evaporation concentrator is used to separate the treated water of the pretreatment filtration membrane into pure water and concentrated water concentrated hygroscopic salts Separating,
Wherein the concentrated water is transported to the hygroscopic salt solution tank.
[3] The apparatus of claim 2, wherein the hygroscopic salt separation membrane comprises any one of a reverse osmosis membrane, a diaphragm membrane, and a spiral membrane.
The apparatus of claim 1, further comprising a third heat exchanger for contacting the hygroscopic salt solution of the hygroscopic salt solution tank with another circulating water to heat the circulating water and supplying the cooled hygroscopic salt solution to the filter The waste heat recovery and the white smoke reduction device of exhaust gas which can be reused in concentrated water.
The method according to claim 1, further comprising: a second heat exchanger for heating the circulating water heated by the first heat exchanger using water vapor separated from the hygroscopic salt solution of the hygroscopic salt solution tank;
The phase separator separates water vapor from the hygroscopic salt solution of the hygroscopic salt solution tank and supplies the water vapor to the second heat exchanger,
And the condensed water of the steam formed in the second heat exchanger is transferred to the first treated water tank.
The apparatus according to claim 1, further comprising a hygroscopic salt solution supply nozzle for supplying a hygroscopic salt solution to an upper end of the heat-
Wherein the hygroscopic salt solution cooled by the first heat exchanger is supplied to the hygroscopic salt solution supply nozzle of the heat-water exchange apparatus.
The apparatus according to claim 1, further comprising an air ejector for supplying low-temperature, high-pressure air to one side of the heat-water exchanging device inside the heat-moisture exchanger to induce condensation of the exhaust gas. Possible recovery of waste heat of exhaust gas and reduction of white smoke.
2. The method according to claim 1, wherein a rare-earth ball layer for adsorbing contaminants in the exhaust gas and decomposing organic matters is provided in the heat-moisture exchanger in a primary contact with the exhaust gas. Waste heat recovery of exhaust gas and reduction of white smoke.
The apparatus of claim 1, wherein the hygroscopic salt solution is an aqueous solution in which hygroscopic salts are dissolved, and the hygroscopic salts are calcium nitrate hydrate.
The method according to claim 1, wherein the hygroscopic salt solution is an aqueous solution in which hygroscopic salts are dissolved, and the hygroscopic salts are ammonium nitrate (NH ₄ NO ₃ ), ammonium sulfate ((NH ₄ ) ₂ SO ₃ ) CIO ₄ ) Any one of ₂ ) potassium hydrogen carbonate (KHCO ₃ ), sodium nitrate (NaNO ₃ ), sodium chlorate (NAClO ₃ ), potassium nitrate (KNO ₃ ), barium nitrate, sodium perchlorate, sodium chloride, calcium chloride, And recovering the waste heat of the exhaust gas capable of being reused in the concentrated water.
The apparatus of claim 1, wherein the concentration of the hygroscopic salt solution is adjusted to 40 to 80 wt%.

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