WO2009154363A2 - System for wet purification of high-temperature gases - Google Patents

Abstract

The present invention relates to a system for wet purification of high-temperature gases using a cooling tower and a heat exchanger to cool and purify high-temperature gases at the same time. The system for wet purification of high-temperature gases according to the present invention comprises: a wet purification device including an inlet duct into which a contaminated gas is introduced, an outlet for discharging a purified gas, a cleaning casing for guiding the contaminated gas introduced into the inlet duct towards the outlet direction and a cleaning liquid injection nozzle installed inside the cleaning casing to inject a cleaning liquid for wet cleaning; a cleaning circulation pipe/pump for returning the cleaning liquid inside the cleaning casing of the wet purification device to the cleaning liquid injection nozzle, with the cleaning circulation pump being installed in the cleaning circulation pipe; a cooling tower including a cooling fan installed at the top to lower the temperature of a heated cooling water and an injection nozzle for the cooling tower installed at the bottom of the cooling fan to spray a cooling water; a cooling circulation pipe/pump for returning the cooling water inside the cooling tower to the injection nozzle for the cooling tower; and a heat exchanger for indirectly cooling the cleaning liquid inside the cleaning circulation pipe with the cooling liquid in the cooling circulation pipe.

Description

Wet Purification System for Hot Gas

The present invention is the result of R & D of the next generation core environmental technology development project supported by Korea Environmental Technology Agency (Task No. 2007-01001-0028-0, title of the project '100,000 m ³ / hr scale hybrid system ').

The present invention relates to a wet gas purification system, and more particularly to a wet gas purification system for hot gas that can purify the gas simultaneously with the cooling of the hot gas using a cooling tower and a heat exchanger.

Emissions from incinerators that burn municipal and industrial wastes in cities include hazardous materials such as dust, acid gases (HCL, SOx, NOx, HF, etc.), heavy metals (Hg, Cd, Pb, As, Zn, etc.) and dioxins. Contains substance. In addition, the exhaust gas discharged during the drying of food waste or harmful substances also contains a large amount of dust or harmful gas and fine dust and gas generating odor. In particular, the exhaust gases generated during the drying of food debris or harmful substances contain volatile organic carbons (VOCs), which cause photochemical reactions to generate smog and cause odors.

As a method of treating the harmful exhaust gas as described above, by spraying alkaline solution to the exhaust gas to remove the dust or neutralized by wet treatment, and then discharged after removing the moisture after incineration in the deodorizing furnace, or neutralized by supplying the lime lime slurry semi-dry It is known to remove dust and discharge dust by passing it through a bag filter after treatment. In addition, in order to remove VOCs and prevent odors and white smoke, a facility for burning VOCs using a catalyst may be separately installed at the rear of the purification apparatus.

On the other hand, the inventor of the present invention has a patent application to the Republic of Korea Patent Application No. 10-2004-0093768, the name of the 'hybrid-type exhaust gas purification apparatus' in the specification of the wet purifying acidic exhaust gas containing dust Later, a method and a device for treating by passing through the bag filter have been proposed (hereinafter, a method of treating the exhaust gas through a bag filter after directly purifying the exhaust gas is called a 'hybrid discharge gas treatment method'). . In addition, the inventor of the present invention, the patent of the invention patent application No. 10-2005-26074 in the Republic of Korea, the specification of the 'exhaust gas wet purifier' in the specification of the removal efficiency of dust, mist, moisture, condensate, etc. A wet purifier is proposed that can be increased and prevent the generation of waste water and the blockage of injection nozzles in the purge chamber. In addition, the inventors of the present invention patented in the Republic of Korea Patent Application No. 10-2005-0036503 in the specification of the 'hybrid type exhaust gas device with a condenser' in the specification of VOC or without a separate catalytic combustion device An exhaust gas purifying apparatus having a condenser capable of removing odors and preventing white smoke is proposed.

Meanwhile, in order to purify the gas by introducing the hot gas into the wet purification facility, the gas must first be cooled. Regarding the system for cooling the hot gas, the following cooling method is used.

The air dilution method is the simplest cooling method, which dilutes a certain temperature and volume of gas with air and cools it to a low temperature suitable for prevention facility connection. When designing such a facility, first, determine the amount of air and temperature required to transport contaminated air from the proposed pollutant source, and then estimate the amount of additional air required to cool this temperature. This method is used in the case of installing an external hood to collect pollutants, and the capacity of the prevention facility should be designed to be much larger than the amount of gas discharged since the external air is diluted.

Next, there is a cooling method by direct contact evaporation of water. If a large amount of hot gas is to be cooled and a small amount of cooling air is added, a method other than air dilution should be adopted. Water evaporation requires a large amount of heat, so spraying and evaporating a small amount of water into the gas can easily cool the gas. This cooling method usually designs the temperature of the exhaust gas after cooling to 100 ° C or higher.

Next, there is a cooling method by natural convection and radiation. When hot gas passes through the duct, the duct is heated and the surrounding air is also heated. When the surrounding air is heated, natural ventilation occurs to dissipate heat around the duct. This phenomenon is called natural convection. In addition, heat is radiated to the surrounding area by radiant heat in the high temperature duct, and this method requires a lot of installation area and pressure loss due to a long duct.

Next, there is a forced air cooling method by air cooling. Hot gas is a method of installing a blower outside the duct to force the outside air around the duct by contact with the duct for cooling, this method requires a long duct and a separate cooling blower is required.

Finally, there is a forced cooling method by water cooling. By making a double pipe through which hot gas can pass water outside the duct, the water is circulated in the double pipe by a pump and cooled. Another method is to cool the air with water like the boiler cooling method.

In the case of the system used for the hot gas purification, it is necessary to lower the temperature of the hot gas to 70 ° C. or lower to maintain the circulation pump performance for circulating the cooling water or the cleaning liquid, and to increase the solubility of the harmful substances contained in the gas in the cleaning liquid. have. Conventionally, in order to cool a hot gas before putting a hot gas into a purification | cleaning apparatus, the separate cooling apparatus for cooling a hot gas in the front of a purification apparatus is provided and used. The separate cooling device is expensive to cool the gas to a desired temperature, and there is a problem in that a large size of the facility takes up a lot of space.

It is an object of the present invention to provide an inexpensive and compact wet purge system for hot gas that can simultaneously purify hot gas to a desired temperature. That is, an object of the present invention is to provide an inexpensive wet purification system for high temperature gas that can simultaneously purify the harmful gases at high temperature without installing a separate heat exchanger for cooling the high temperature gas in front of the wet purification apparatus. It is.

The wet purifying system for hot gas according to the present invention includes an inlet duct through which contaminated gas is introduced, an outlet through which clean gas is discharged, and a cleaning case and wet cleaning for guiding the gas introduced into the inlet duct to flow in the outlet direction. A wet purifying apparatus including a cleaning liquid spray nozzle installed inside the cleaning case to spray the cleaning liquid for cleaning, a circulating piping for supplying the cleaning liquid inside the cleaning case of the wet cleaning apparatus to the cleaning liquid spray nozzle; A cooling tower including a cleaning circulation pump installed in the cleaning circulation pipe, a cooling fan installed at an upper portion to lower the temperature of the heated cooling water, and a cooling tower injection nozzle installed at a lower portion of the cooling fan to spray the cooling water; Cooling for supplying the cooling nozzle to the cooling tower by returning the cooling water inside the cooling tower And a ring pipe and a cooling circulation pump, characterized in that it comprises a heat exchanger for indirectly cooling the washing liquid within the washing cycle for the pipe to the cooling water circulation of the cooling piping.

According to the present invention, by spraying a large amount of the cleaning liquid to the wet purifier, the temperature of the harmful gas is drastically lowered by the injected cleaning liquid to increase the solubility of the cleaning solution of the contaminants contained in the harmful gas. As the cleaning liquid is continuously returned and used, the temperature of the cleaning liquid is effectively cooled by an indirect cooling method using a heat exchanger and cooling water. Therefore, it is possible to maintain the temperature of the circulating cleaning liquid at an appropriate temperature to maximize the cleaning effect, it is possible to stably use the cleaning liquid circulation pump.

In the case of the wet purifying system for hot gas according to the present invention, high temperature harmful gas can be cooled and gas-purified at low cost without installing a separate heat exchanger for cooling the hot gas in front of the wet purifying facility. In addition, it is possible to increase the purification efficiency by lowering the temperature to maintain the performance of the circulation pump, increase the solubility of the cleaning liquid of the harmful substances contained in the gas.

1 is a schematic diagram of an embodiment of a wet purge system for hot gas according to the present invention.

2 is a schematic diagram of another embodiment of a wet purge system for hot gas according to the present invention.

3 is a schematic diagram of another embodiment of a wet purge system for hot gas according to the present invention.

4 is a schematic diagram of another embodiment of a wet purge system for hot gas according to the present invention.

<Short description of drawing symbols>

100 .... Induction duct 101 .... Wet purifier

102..Exit 103..Cleaning circulation pump

104..Cleaning circulation pipe 105 .... Cleaning nozzle

106 .... eliminator 107 .... filled floor

108..Mixing element 109 .... Cleaning case

201 .. cooling tower 203 cooling fan

204..Cooling circulation pump 205..Cooling circulation piping

206 .... Eliminator for cooling tower 207 .... Heat exchanger

208 .... Filling layer for cooling tower

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a schematic diagram of an embodiment of a wet purge system for hot gas according to the present invention. Referring to FIG. 1, the wet purifying system for hot gas includes a gas purifying unit including a wet purifying apparatus 101, a cleaning circulation pipe 104, and a cleaning circulation pump 103, a cooling tower 201, and a cooling system. A cooling unit comprising a pump 204 and a cooling circulation pipe 205 and a heat exchanger 207 positioned between the cleaning circulation pipe 104 and the cooling circulation pipe 205.

The wet purifier 101 includes an inlet duct 100 into which contaminated hot gas is introduced, an outlet 102 from which cleaned gas is discharged, and a gas introduced into the inlet duct 100 toward the outlet 102. The cleaning case 109 for guiding the flow, the cleaning liquid injection nozzle 105 installed inside the cleaning case 109 to spray the cleaning liquid for cleaning the hot gas introduced from the inlet duct 100 and the cleaned And an eliminator 106 for removing moisture contained in the gas.

The cleaning circulation pipe 104 connects the liquid storage part of the lower part of the cleaning case 109 and the cleaning liquid injection nozzle 105. The cleaning liquid sprayed from the cleaning liquid injection nozzle 105 and stored in the lower portion of the cleaning case 109 is supplied to the cleaning liquid injection nozzle 105 through the cleaning circulation pipe 104 via the heat exchanger 207.

The cleaning circulation pump 103 is installed between the heat exchanger 207 and the cleaning liquid injection nozzle 105. This is to allow the cleaning liquid cooled through the heat exchanger 207 to pass through the cleaning circulation pump 103 so as to prevent a decrease in performance and life of the cleaning circulation pump 103 due to the temperature rise.

The cooling tower 201 includes a cooling fan 203, an eliminator 206 for a cooling tower, an injection nozzle 209 for a cooling tower, and a packed layer 208 for a cooling tower.

The cooling fan 203 is positioned above the cooling tower 201 and rotates when power is supplied to the connected motor to supply outside air to the inside of the cooling tower 201 to cool the cooling water whose temperature is increased by heat exchange.

The cooling tower eliminator 206 is located under the cooling fan 203 and removes moisture contained in the gas discharged from the cooling tower 201 to the outside. As the outside air enters and comes into contact with the cooling water, a portion of the cooling water is evaporated, so that the temperature of the cooling water is lowered. When it is discharged to the outside in a state containing water there is a possibility that white smoke is generated in the upper portion of the cooling tower 201 to remove the moisture from the eliminator 206 for the cooling tower. The eliminator 206 for the cooling tower is used in various forms such as a wire mesh pad, a packed bed, and a zigza balplate.

The cooling tower injection nozzle 209 is located at the lower part of the cooling tower eliminator 206 and is connected to the end of the cooling circulation pipe 205 to receive the cooling water whose temperature has risen by heat exchange in the heat exchanger 207. Spray.

The packed bed 208 for the cooling tower is located between the spray nozzle 209 for the cooling tower and the surface of the cooling water filled in the cooling tower 201. The filling layer 208 for the cooling tower is installed to increase the cooling area by increasing the contact area and time of the outside air and the cooling water supplied by the cooling fan 203. Fill layer 208 for a cooling tower is comprised of fills of various geometries and fill supports that support the fills.

The cooling circulation pipe 205 connects the lower part of the cooling tower 201 and the injection nozzle 209 for the cooling tower. The cooling water sprayed from the cooling tower injection nozzle 209 and stored in the lower portion of the cooling tower 201 passes through the heat exchanger 207 through the cooling circulation pipe 205 and back to the cooling nozzle injection nozzle 209. Supplied.

The cooling circulation pump 204 is installed in the cooling circulation pipe 205 disposed between the heat exchanger 207 and the lower cooling water storage unit of the cooling tower 201. The cooling water cooled through the cooling tower 201 passes through the cooling circulation pump 204, to prevent a decrease in performance and life of the cooling circulation pump 204 due to the temperature rise.

The heat exchanger 207 used a plate heat exchanger in which a plurality of heat exchange plates overlapped with each other so as to be airtight so that a plurality of cleaning circulation pipes 104 flow paths and cooling circulation pipe 205 flow paths were alternately repeatedly arranged. .

Hereinafter, the operation method of the wet purifying system for hot gas of this embodiment comprised as mentioned above is demonstrated.

When a high temperature harmful gas is introduced into the inlet duct 100 of the wet purifier 101, the circulating pump 103 is operated and the cleaning liquid is supplied to the cleaning injection nozzle 105 through the cleaning circulation pipe 104.

When the cleaning liquid is injected from the cleaning injection nozzle 105, the harmful gas is absorbed or reacted with the harmful gas to remove contaminants.

The cooling pump 204 and the cooling fan 203 of the cooling tower 201 operate simultaneously with the circulation pump 103, and the cooling water in the cooling tower 201 is along the cooling circulation pipe 205 for the heat exchanger 207. Is supplied.

In the heat exchanger 207, heat exchange occurs by conduction, and the temperature of the cleaning liquid raised by the high temperature harmful gas drops to a temperature of 70 ° C. or less, which is an appropriate use temperature of the circulation pump 103.

Cooling water whose temperature is increased by heat exchange in the heat exchanger 207 is supplied to the cooling tower 201 through the cooling circulation pipe 205 and is injected through the cooling water injection nozzle inside the cooling tower 201. The injected cooling water wets the filling layer 208 for the cooling tower inside the cooling tower 201, and is cooled by contacting the outside air supplied through the cooling fan 203. When the outside air entering the cooling tower 201 is discharged outside the cooling tower 201, moisture is removed through the cooling tower eliminator.

The cooling water cooled in the cooling tower 201 is again supplied to the heat exchanger 207 via the cooling circulation pipe 205 to exchange the temperature of the cleaning liquid with an appropriate use temperature of 70 ° C. through heat exchange with the cleaning circulation pipe 104. It lowers to the following temperature.

When this process is repeated, the cleaning liquid heated by the high temperature harmful gas is cooled through the heat exchanger 207 to maintain a temperature below 70 ° C., which is a proper use temperature of the circulation pump 103. Therefore, the performance of the circulating pump can be maintained, and the solubility of the harmful gas in the cleaning liquid is higher as the temperature of the cleaning liquid is lower, thereby increasing the gas purification efficiency in the wet purifier 101.

2-4 are schematic diagrams of other embodiments of a wet purge system for hot gas according to the present invention. Members having the same function are assigned the same member numbers even if they differ in form.

Second Embodiment

2, the wet purifying system for hot gas according to the second embodiment of the present invention is the same as the first embodiment except that the wet purifying device 101 is disposed so that noxious gas flows in the horizontal direction. Do.

Third Embodiment

Referring to FIG. 3, a wet purifying system for a hot gas according to a third embodiment of the present invention is provided between a cleaning spray nozzle 105 and a bottom cleaning spray nozzle 105 and a bottom of a cleaning case 109. The same as in the first embodiment except that the filling layers 107 are provided, respectively. The filling layer 107 is composed of a filling material and a filling support having various geometric shapes, and has an effect of increasing the contact area of the cleaning liquid and the gas and reducing the pressure loss.

Fourth Example

Referring to FIG. 4, the wet purifying system for hot gas according to the third embodiment of the present invention has two cleaning cases horizontally installed with two cleaning cases 109 in which the wet purifying apparatus 101 is installed vertically. It is composed of the case 109, and is the same as the first embodiment except that the mixing member 108 capable of forming a vortex is provided inside the cleaning case 109 which is installed vertically.

As can be seen in the second to fourth embodiments, the gas purifying unit, the cooling tower 201, and the cooling pump, which consist of various types of wet purifying apparatus 101, a cleaning circulation pipe 104, and a circulation pump 103, 204) and a cooling section comprising cooling circulation pipes 205, and a heat exchanger 207 is installed between the cleaning circulation pipe 104 and the cooling circulation pipe 205 to manufacture a wet purifying system for hot gas. can do.

As described above, the wet purifying system for hot gas according to the present invention has been described with reference to preferred embodiments, but the protection scope of the present invention is limited only by the matters described in the claims, and the person skilled in the art of the present invention It is possible to improve and change the technical idea of the invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

Claims (5)

An inlet duct into which contaminated gas is introduced, an outlet from which cleaned gas is discharged, a cleaning case for guiding the gas introduced into the inlet duct to flow toward the outlet direction, and an inside of the cleaning case to spray a cleaning solution for wet cleaning. A wet purifying apparatus including a cleaning liquid spray nozzle installed therein, A cleaning circulation pipe for returning the cleaning liquid inside the cleaning case of the wet purifier to the cleaning liquid injection nozzle, and a cleaning circulation pump installed in the cleaning circulation pipe; A cooling tower including a cooling fan installed at an upper portion to lower the temperature of the heated cooling water and a spray nozzle for a cooling tower installed at a lower portion of the cooling fan so as to spray the cooling water; A cooling circulation pipe and a cooling circulation pump for returning the cooling water inside the cooling tower and supplying the cooling water to the injection nozzle for cooling tower; And a heat exchanger for indirectly cooling the cleaning liquid in the cleaning circulation pipe with the cooling water of the cooling circulation pipe. The method of claim 1, The cooling tower further comprises a cooling tower eliminator installed between the cooling tower injection nozzle and the cooling fan. The method according to claim 1 or 2, The cooling tower is a wet purification system for hot gas, characterized in that further provided with a cooling tower packed bed installed under the cooling tower injection nozzle. The method of claim 1, The heat exchanger is a plate heat exchanger or pipe heat exchanger or shell tube heat exchanger, characterized in that the wet purification system for hot gas. The method of claim 1, The cleaning circulation pump is a wet purifying system for hot gas, characterized in that installed in the cleaning circulation pipe between the heat exchanger and the nozzle.

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