JP2009154151A - Deodorization apparatus and deodorization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an deodorization method capable of deodorizing an offensive gas containing high concentration of offensive components generated from a composting apparatus. <P>SOLUTION: The offensive gas is deodorized by cooling an exhaust gas containing the offensive gas containing ammonia and carbon dioxide and moisture discharged from the composting apparatus 11 with a heat exchanger 12 to condense the moisture to separate the exhaust gas into the offensive gas and condensed water and allow the separated offensive gas and condensed water to contact each other in packed towers 14, 15, 16. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a deodorizing apparatus and a deodorizing method for deodorizing odorous gas generated from a composting apparatus for livestock excreta.
Odor components contained in this odor gas are, for example, malodorous substances stipulated in the Malodor Control Law, and specifically ammonia, sulfur compounds, organic acids, etc., but here, in particular, composting livestock excreta The present invention relates to a method for deodorizing ammonia, which is a main component of odor gas generated from the inside of the apparatus.

  Livestock farms where poultry, pigs, cattle, and other livestock are raised, livestock excretion and livestock collection from these farms, and compost production using these excreta Offensive odors generated from workplaces, factories, etc. cause troubles with neighboring residents and are a major problem affecting the lives of neighboring residents.

In particular, with the recent advancement of residential areas in the suburbs, the distance between livestock farms and factories and private houses tends to be closer, and the need for complete deodorization of off-flavors and odors is increasing.
In general, one pig in a pig farm is said to generate excrement for 10 humans, and pig farms that handle many pigs are struggling to respond to complaints from neighboring residents about the bad odor that occurs. Is the reality.

In addition, most of the livestock excreta are composted. Complaints from neighboring residents have been received regarding the intense odor generated from factories and workplaces that produce this compost, and deodorization is indispensable. ing.
As this deodorizing method and deodorizing apparatus, for example, a so-called biological deodorizing method using microorganisms has been proposed (see, for example, Patent Document 1).

The deodorization method described in Patent Document 1 is a method in which a gas containing an odor component is fed into a microorganism culture solution prepared to a required concentration, and this is bubbled to remove the odor component.
In this method, when removing the odor component in the microorganism culture solution, the microorganisms in the microorganism culture solution can be cultured and proliferated by supplying an energy source to the microorganism culture solution in which the microorganisms are reduced by the deodorizing action of the microorganism.
Then, by circulating the microorganism culture solution restored to the required concentration by the culture growth in the deodorizing apparatus, the odor gas containing the odor component by the microorganism culture solution always restored to the required concentration by the culture growth of the microorganism. Can be deodorized.

JP 2007-283239 A

  However, the deodorization method using microorganisms is difficult to process when the concentration of ammonia contained in the odor gas is high. For this reason, it cannot be applied when a device that generates a high volume of odor gas containing high-temperature and high-concentration ammonia such as a vertical rapid fermentation device is used as a composting device for livestock manure.

  In addition, the deodorizing method using microorganisms has a problem that the deodorizing efficiency is extremely deteriorated if the treatment is not performed between 15 and 35 ° C., which is a suitable growth range of microorganisms, because the deodorizing effect is affected by the temperature. .

  In order to solve the above-described problems, the present invention provides a deodorizing apparatus and a deodorizing method capable of deodorizing odorous gas containing a high-concentration odorous component generated from a composting apparatus.

  The deodorizing apparatus of the present invention includes a composting apparatus that discharges odorous gas containing ammonia and carbon dioxide and moisture, a heat exchanger that cools the exhaust from the composting apparatus and condenses moisture, and condenses in the heat exchanger And a packed tower for contacting the odor gas with the water.

  Further, the deodorizing method of the present invention is an odor gas containing ammonia and carbon dioxide discharged from a composting apparatus, and an exhaust gas containing moisture is cooled by a heat exchanger to condense the moisture and the exhaust gas is odor gas. And the condensed water, and the separated odor gas and the condensed water are brought into contact with each other in a packed tower.

  According to the deodorizing apparatus and the deodorizing method of the present invention, the moisture discharged from the composting apparatus is condensed by the heat exchanger. And the odor gas discharged | emitted from a composting apparatus and the water condensed with the heat exchanger are made to contact in a packed tower. Thereby, ammonia and carbon dioxide contained in the odor gas are dissolved in the condensed water. And since most of the ammonia contained in the odor gas is dissolved in the condensed water, the exhaust from the packed tower does not substantially contain ammonia, and the odor gas can be deodorized.

  Therefore, for example, in a composting apparatus that generates high-concentration ammonia such as a vertical rapid fermentation apparatus, ammonia generated from the composting apparatus is recovered using carbon dioxide and water generated from the composting apparatus. be able to. That is, a high concentration ammonium carbonate solution is obtained by recovering ammonia, which is the main component of the odor, from the odor gas generated from the composting apparatus and reacting it with carbon dioxide or carbonic acid in water. For this reason, by this deodorizing apparatus and deodorizing method, it can be set as exhaust which hardly contains ammonia which is the main component of odor.

  ADVANTAGE OF THE INVENTION According to this invention, the odor gas containing ammonia discharged | emitted from a composting apparatus can be deodorized very effectively by making it react with the carbon dioxide or carbonic acid in water, the ammonia which is a main component of an odor.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a block diagram of a deodorizing apparatus according to an embodiment of the present invention.
1 includes a composting device 11, a heat exchanger 12, a first water tank 13, a first packed tower 14, a second packed tower 15, a third packed tower 16, and a first packed tower 16. 2 water tanks 17.

The composting apparatus 11 is an apparatus that is supplied with air from the outside, fertilizes livestock excrement (organic waste) in the apparatus, and composts it. As the composting apparatus 11, for example, a vertical rapid fermentation apparatus that continuously and aerobically fertilizes livestock excrement is used.
The composting apparatus 11 supplies a livestock excrement input port formed at an upper part thereof, an agitator that constantly or periodically stirs the livestock excrement input from the input port, and supplies air from the outside into the apparatus. For example, an air heater and an electric heater for air heating installed at an intermediate portion of the air duct are configured.
A gas feed pipe 31 is connected to the upper part of the composting apparatus 11. The gas pipe 31 is connected to the heat exchanger 12 from the composting apparatus 11 through the blower 25.

  In the composting apparatus 11, when fermenting and drying livestock excreta, odorous gas containing ammonia as a main component and a small amount of other various organic acids is generated, and carbon dioxide and livestock excrement are dried. A large amount of water is generated. Then, by driving the blower 25, exhaust gas containing odor gas, carbon dioxide, moisture and the like generated in the composting apparatus 11 is supplied to the heat exchanger 12 through the gas feed pipe 31.

And in this heat exchanger 12, the moisture contained in exhaust_gas | exhaustion is condensed by cooling the exhaust gas containing the odor gas containing ammonia and the carbon dioxide supplied from the composting apparatus 11, or a water | moisture content. Thereby, the exhaust gas supplied from the composting apparatus 11 is separated into a gas such as ammonia or carbon dioxide and condensed water.
A pipe 32 and a gas feed pipe 34 are connected to the heat exchanger 12. The pipe 32 is connected from the heat exchanger 12 to the first water tank 13. This pipe 32 sends the condensed water separated from the exhaust gas supplied from the composting apparatus 11 to the first water tank 13. The gas feed pipe 34 is connected to the lower part of the first packed tower 14 from the heat exchanger 12.

The first water tank 13 collects the condensed water in the heat exchanger 12 through the pipe 32.
A pipe 37, a pipe 38, and a gas feed pipe 33 are connected to the first water tank 13.
The pipe 37 supplies air from the outside into the first water tank 13 through the blower 18. The pipe 38 is connected to the spray nozzle 20 provided in the upper part of the third packed tower 16 from the first water tank 13. The gas feed pipe 33 is connected to the gas feed pipe 34 from the first water storage tank 13.
Moreover, the remainder supplied to the 3rd packed tower 16 among the condensed water collect | recovered by the 1st water tank 13 is drained by overflow.

In the condensed water collected in the first water tank 13, ammonia and carbon dioxide contained in the exhaust gas from the composting apparatus 11 are dissolved. For this reason, by driving the blower 18, air is supplied from the pipe 37 connected to the first water tank 13, and the condensed water collected in the first water tank is aerated with air. Since the condensed water is aerated in the first water tank in this way, ammonia, carbon dioxide and the like contained in the condensed water are supplied to the gas feeding pipe 34 through the gas feeding pipe 33.
The gas feed pipe 34 supplies odor gas containing ammonia and carbon dioxide from the heat exchanger 12 and the gas feed pipe 33 to the lower part of the first packed tower 14.

  The 1st packed tower 14, the 2nd packed tower 15, and the 3rd packed tower 16 are connected in series by piping, respectively. These are counter flow contact type packed towers in which condensed water is supplied from above to below and odorous gas is supplied from below to above.

The first packed tower 14 is provided with a filler 26 in the tower. In addition, a spray nozzle 24 is disposed on the top of the packing material 26 of the first packed tower 14. A circulating water tank 45 is installed in the lower part of the first packed tower 14.
A gas feed pipe 34, a gas feed pipe 35, and an overflow pipe 41 are connected to the first packed tower 14. A circulating pipe 48 is connected to the circulating water tank 45. The gas feed pipe 35 is connected from the upper part of the first packed tower 14 to the lower part of the second packed tower 15. The overflow pipe 41 is connected to the second water storage tank 17 from the upper part of the circulating water tank 45 at the lower part of the first packed tower 14. A pipe 40 is connected to the spray nozzle 24 arranged at the upper part of the first packed tower 14. Further, a circulation pipe 48 from the circulating water tank 45 is connected to the pipe 40.

The second packed tower 15 is provided with a filler 27 in the tower. In addition, a spray nozzle 22 is disposed above the filler 27 of the second packed tower 15. A circulating water tank 44 is installed at the lower part of the second packed tower 15.
A gas feed pipe 35, a gas feed pipe 36, and a pipe 40 are connected to the second packed tower 15. A circulating pipe 47 is connected to the circulating water tank 44. The gas feed pipe 36 is connected from the upper part of the second packed column 15 to the lower part of the third packed column 16. The pipe 40 is connected to the spray nozzle 24 disposed in the first packed tower 14 through the pump 23 from the lower part of the second packed tower 15.
A pipe 39 is connected to the spray nozzle 22 arranged at the upper part of the second packed tower 15. A circulation pipe 47 from the circulating water tank 44 is connected to the pipe 39.

The third packed column 16 is provided with a packing material 28 in the column, and a spray nozzle 20 is disposed above the packing material 28 of the third packed column 16. A circulating water tank 43 is installed in the lower part of the third packed tower 16.
A gas feed pipe 36, a pipe 39, and an exhaust pipe 42 are connected to the third packed tower 16. A circulating pipe 46 is connected to the circulating water tank 43. The piping 39 is connected to the spray nozzle 22 disposed in the second packed tower 15 via the pump 21. A pipe 38 is connected to the spray nozzle 20 disposed at the upper part of the third packed tower 16. A circulation pipe 47 from the circulating water tank 46 is connected to the pipe 38.
The exhaust pipe 42 passes from the first packed tower 14 to the third packed tower 16, and the gas in which the concentration of the odor component is sufficiently reduced is exhausted.

  The second water tank 17 stores water discharged from the lower portion of the first packed tower 14 through the overflow pipe 41. The water stored in the second water tank 17 is water in which ammonia and carbon dioxide contained in the odor gas are dissolved by gas-liquid contact in the packed tower. The water also contains ammonium carbonate, which is a reaction product of dissolved carbonic acid and ammonia.

  As described above, in the deodorizing apparatus 10, when ammonia is recovered in the packed tower, carbon dioxide generated from the composting apparatus 11 and moisture generated from the composting apparatus 11 are condensed. For this reason, ammonia which is the main component of the odor component generated from the composting apparatus 11 can be recovered without adding a substance for absorbing moisture from the outside or the odor component contained in the odor gas.

  Next, a method for deodorizing ammonia, which is the main component of the odor component, from the odor gas using the above-described deodorization apparatus 10 will be described. In the following description, the configuration of the deodorizing apparatus 10 will be described with the same reference numerals as those used in FIG.

  First, the exhaust from the composting apparatus 11 is supplied to the heat exchanger 12 through the gas feed pipe 31 by driving the blower 25. Since the exhaust from the composting apparatus 11 supplied to the heat exchanger 12 is cooled by the heat exchanger 12, moisture contained in the exhaust is condensed. That is, the exhaust gas from the composting apparatus 11 is normally discharged at a temperature higher than the outside air temperature, but in the heat exchanger 12, this high temperature exhaust gas is lowered to the outside air temperature. Can be condensed.

  Next, the odor gas from which moisture has been removed by the heat exchanger 12 is discharged from the heat exchanger 12 through the gas feed pipe 34. Then, the water condensed in the heat exchanger 12 is collected in the first water tank 13 through the pipe 32. Subsequently, the water collected in the first water tank is aerated by the blower 18 so that ammonia and carbon dioxide dissolved in the water are taken out as gases. Ammonia and carbon dioxide extracted by this aeration are supplied to the gas feed pipe 34 through the gas feed pipe 33.

Next, the odor gas containing ammonia and carbon dioxide separated by the heat exchanger 12 and the first water storage tank 13 is circulated to the first packed tower 14 at the lower part of the packing material 26 by the gas feed pipe 34. Supply from above the water tank 45. Then, the supplied odor gas passes through the filler 26 and is discharged from the gas feed pipe 35 connected to the upper portion of the first packed tower 14.
The odor gas discharged from the gas feed pipe 35 is supplied to the second packed tower 15 from below the filler 27 and from above the circulating water tank 44. Then, the supplied odor gas passes through the filler 27 and is discharged from the gas feed pipe 36 connected to the upper part of the second packed tower 15.
The odor gas discharged from the gas feed pipe 36 is supplied to the third packed tower 16 from below the filler 28 and from above the circulating water tank 43. The supplied odor gas passes through the filler 28 and is discharged into the atmosphere from the exhaust pipe 42 connected to the upper portion of the third packed tower 16.

Further, the condensed water collected in the first water storage tank 13 is supplied to the spray nozzle 20 disposed on the upper portion of the filler 28 of the third packed tower 16 through the pipe 19 through the pump 19. Then, the condensed water supplied to the spray nozzle 20 is jetted downward from the upper part of the filler 28. Further, the condensed water jetted from the spray nozzle 20 is stored in the circulating water tank 43. Then, by driving the pump 19, the condensed water stored in the circulating water tank 43 is supplied from the circulating pipe 46 to the pipe 38, and is again injected from the spray nozzle 20 to the third packed tower 16. As described above, the condensed water supplied from the first water storage tank 13 to the third packed tower 16 circulates in the third packed tower 16.
Further, the condensed water can be supplied almost uniformly to the filler 28 by spraying the condensed water with the spray nozzle 20.

  Further, the condensed water stored in the circulating water tank 43 is discharged from a pipe 39 connected to the lower part of the third packed tower 16. And the condensed water discharged | emitted from the piping 39 is supplied to the spray nozzle 22 arrange | positioned through the pump 21 at the upper part of the filler 27 of the 2nd packed tower 15. FIG. The condensed water supplied to the spray nozzle 22 is jetted downward from the upper portion of the filler 27. Further, the condensed water jetted from the spray nozzle 22 is stored in the circulating water tank 44. Then, by driving the pump 21, the condensed water stored in the circulating water tank 44 is supplied from the circulating pipe 47 to the pipe 39 and is again injected from the spray nozzle 22 to the second packed tower 15. As described above, the condensed water supplied from the third packed tower 16 circulates in the second packed tower 15 by the circulating water tank 44, the circulating pipe 47, the piping 39, and the spray nozzle 22.

  Further, the condensed water stored in the circulating water tank 44 is discharged from the pipe 40 connected to the lower part of the second packed tower 15. And the condensed water discharged | emitted from the piping 40 is supplied to the spray nozzle 24 arrange | positioned through the pump 23 at the upper part of the filler 26 of the 1st packed tower 14. The condensed water supplied to the spray nozzle 24 is jetted downward from the upper part of the filler 26. Further, the condensed water jetted from the spray nozzle 24 is stored in the circulating water tank 45. Then, by driving the pump 23, the condensed water stored in the circulating water tank 45 is supplied from the circulating pipe 48 to the pipe 40 and is again injected from the spray nozzle 20 to the second packed tower 15. As described above, the condensed water supplied from the second packed tower 15 circulates in the first packed tower 14 by the circulating water tank 45, the circulating pipe 48, the piping 40, and the spray nozzle 24.

  The condensed water sprayed from the spray nozzle 24 and stored in the circulating water tank 45 is discharged by overflow from an overflow pipe 41 connected to the upper part of the circulating water tank 45 in the lower part of the first packed tower 14. Then, the condensed water discharged from the overflow pipe 41 is collected in the second water tank 17.

  As described above, the odor gas and the condensed water are brought into contact with each other in the packed tower by supplying the odor gas from the lower part of the packed tower and supplying the condensed water from the spray nozzle of the packed tower. In addition, since the packed tower is provided with a packing material, this packing material increases the contact area between the odor gas and the condensed water, improves the efficiency of gas-liquid contact, and reduces the ammonia and dioxide contained in the odor gas. Carbon can be efficiently dissolved in condensed water.

  The odor gas supplied through the gas feed pipe 34 to the lower part of the first packed tower 14 includes ammonia and carbon dioxide having substantially the same concentration as the odor gas exhausted from the composting apparatus 11. The odor gas ammonia and carbon dioxide supplied from the gas feed pipe 34 are absorbed by the condensed water supplied from the spray nozzle 24. The condensed water supplied from the spray nozzle 24 is in contact with the odor gas in the third packed tower 16 and the second packed tower 15. For this reason, ammonia and carbon dioxide are already dissolved in the condensed water.

The odor gas supplied to the first packed tower 14 comes into contact with the condensed water supplied from the spray nozzle 24, whereby ammonia and carbon dioxide are dissolved in the condensed water. For this reason, the odor gas discharged from the upper portion of the first packed tower 14 through the gas feed pipe 35 has a lower concentration of ammonia, which is an odor component, than the odor gas in the gas feed pipe 34.
Moreover, the condensed water supplied from the spray nozzle 24 is dissolved in ammonia and carbon dioxide by contacting the odor gas in the first packed tower 14. Then, after being stored in the circulating water tank 45, ammonia and carbon dioxide dissolved in the condensed water can be concentrated by being supplied again from the circulating pipe 48 and the piping 40 into the first packed tower 14. For this reason, the condensed water discharged from the lower portion of the first packed tower 14 through the overflow pipe 41 has more ammonia and carbon dioxide dissolved therein than the condensed water supplied from the second packed tower 15.

  Similarly to the first packed tower 14 described above, in the second packed tower 15, the odor gas supplied from the lower portion of the second packed tower 15 and the condensed water supplied from the spray nozzle 22 come into contact with each other. To do. For this reason, the odor gas discharged from the second packed tower 15 through the gas feed pipe 36 has a lower concentration of ammonia, which is an odor component, than the odor gas supplied through the gas feed pipe 35. Further, the condensed water discharged from the second packed tower 15 through the pipe 40 is stored in the circulating water tank 44 and then supplied again from the circulating pipe 47 and the pipe 39 into the second packed tower 15. Thus, ammonia and carbon dioxide dissolved in the condensed water can be concentrated. For this reason, more ammonia and carbon dioxide are dissolved than the condensed water supplied from the third packed tower 16.

Further, in the third packed tower 16, the odor gas supplied from the lower part of the third packed tower 16 and the condensed water supplied from the spray nozzle 20 come into contact with each other. The condensed water supplied from the spray nozzle 20 is condensed water aerated in the first water storage tank 13. For this reason, ammonia is hardly dissolved in this condensed water. Then, the condensed water supplied from the spray nozzle 20 comes into contact with the odor gas supplied from the gas feed pipe 36 in the third packed tower 16, and ammonia and carbon dioxide contained in the odor gas are dissolved in the condensed water. To do. Further, after being stored in the circulating water tank 43, the ammonia and carbon dioxide dissolved in the condensed water are concentrated by being supplied again into the third packed tower 16 from the circulating pipe 46 and the pipe 38. For this reason, the condensed water discharged from the lower part of the third packed tower 16 through the pipe 39 has more ammonia and carbon dioxide dissolved therein than the condensed water supplied from the first water storage tank 13.
Further, the gas discharged from the third packed tower 16 through the exhaust pipe 42 is sufficiently reduced in concentration of the odor component because the odor component ammonia contained in the odor gas is dissolved in the condensed water by gas-liquid contact. is doing.

  In addition, a second water tank 17 is connected by an overflow pipe 41 from an upper part of a circulating water tank 45 installed at the lower part of the first packed tower 14. Then, the condensed water in which ammonia and carbon dioxide are dissolved at a high concentration in the first packed tower 14 is discharged from the lower portion of the first packed tower 14 through the overflow pipe 41 and collected in the second water storage tank 17. The The condensed water recovered in the second water tank 17 is a high concentration ammonium carbonate solution. In addition, ammonia, carbon dioxide, ammonium ions, and carbonate ions contained in the odor gas are dissolved in the condensed water.

  In this way, by using the first packed tower 14 to the third packed tower 16 to bring the odor gas and the condensed water into countercurrent contact in a multistage manner, the ammonia contained in the odor gas is absorbed by the condensed water. can do. As a result, the exhaust gas from the deodorizing apparatus 10 contains almost no ammonia, which is the main component of the odor component, so that the odor gas containing the high-concentration odor component generated from the composting apparatus can be deodorized.

  The odor gas discharged from the composting apparatus 11 includes ammonia as a main component of the odor component. Further, the exhaust gas discharged from the composting apparatus 11 contains about 10 times as much carbon dioxide as ammonia.

  Usually, when only ammonia is dissolved in water, it does not dissolve above the solubility of ammonia. However, since the odor gas contains about 10 times as much carbon dioxide as ammonia, the ammonia contained in the odor gas becomes ammonium hydroxide (ammonium ion) when dissolved in water. Carbon dioxide dissolves in water, so that part of the dissolved carbon dioxide becomes carbonic acid (carbonate ions). Then, by dissolving ammonia and carbon dioxide in water, neutralization reaction of acid and base by ammonium hydroxide and carbonic acid occurs, and ammonium carbonate or ammonium hydrogen carbonate and similar salts thereof are generated.

As described above, ammonia dissolved in water becomes ammonium carbonate or ammonium hydrogen carbonate and its similar salt through ammonium hydroxide, so that the ammonia concentration in water decreases. And the ammonia in odor gas can melt | dissolve in water by the part for which the ammonia concentration in water fell.
Similarly, carbon dioxide is converted to ammonium carbonate or ammonium hydrogen carbonate through carbonic acid, so that the concentration of carbonic acid in water decreases. And since the carbonic acid density | concentration in water fell, the carbon dioxide in odor gas can melt | dissolve in water. In addition, since carbon dioxide is present in the odor gas at a concentration of about 10 of ammonia, the ammonia in the odor gas does not generate surplus in the gas and water with respect to carbon dioxide.
As described above, ammonia and carbon dioxide are dissolved in water and ammonium carbonate or ammonium hydrogen carbonate is continuously generated, so that ammonia in the odor gas can be efficiently dissolved in water.
Thus, by dissolving carbon dioxide contained in the odor gas in water in the packed tower simultaneously with ammonia, the ammonia can be dissolved and recovered more than the solubility of ammonia in water.

  It also dissolves in condensed water when it contains odorous components of odorous gases emitted from composting equipment, such as sulfur compound odorous components such as hydrogen sulfide and methyl mercaptan, and odorous components such as organic acids. It can be efficiently recovered by neutralization with ammonia. For this reason, it is possible to deodorize even when the odor gas contains a odor component such as a sulfur compound odor component and an organic acid.

In the above-described embodiment, in order to sufficiently reduce the ammonia concentration exhausted from the deodorization apparatus, the number of packed towers and the configuration of the packed towers for configuring the deodorization apparatus are determined according to the concentration of ammonia in the odor gas and the dioxide dioxide. It can be changed according to the carbon concentration.
For example, it is possible to change the packing material, specific surface area, or packing rate of the packed tower, or to change the number of packed towers. Further, the gas-liquid contact between the condensed water and the odor gas in the packed tower may be either a cocurrent contact or a countercurrent contact. In this way, by changing the configuration of the deodorizing device as necessary, it is possible to optimize the absorption of ammonia and carbon dioxide by the condensed water and sufficiently reduce the concentration of ammonia exhausted from the deodorizing device.

Further, carbon dioxide may be supplied to the condensed water stored in the circulating water tanks 43, 44, 45 by microbubbles or air stones. The carbon dioxide concentration of the condensed water can be increased by dissolving the carbon dioxide in the condensed water stored in the circulating water tanks 43, 44, and 45 with microbubbles or air stones. Therefore, it is possible to efficiently dissolve ammonia in condensed water by gas-liquid contact with ammonia in the packed tower.
For example, carbon dioxide contained in the exhaust gas from the composting apparatus 11 can be supplied to the circulating water tanks 43, 44, and 45 described above. Further, carbon dioxide can be supplied by connecting a carbon dioxide cylinder, a boiler, an engine, or the like that discharges carbon dioxide into the circulating water tanks 43, 44, and 45 from the outside.

Hereinafter, the present invention will be described in detail by experimental examples.
The deodorizing apparatus used for experiment is shown in FIG. The deodorizing apparatus 50 shown in FIG. 2 includes an ammonia cylinder 59, a carbon dioxide cylinder 61, a first packed tower 62, a second packed tower 63, and a circulating water tank 64.

  Ammonia gas was supplied from the ammonia cylinder 59 to the deodorization apparatus 50, and carbon dioxide gas was supplied from the carbon dioxide cylinder 61 to the deodorization apparatus 50, so that it was used as a pseudo composting apparatus. The ammonia gas supplied from the ammonia cylinder 59 and the carbon dioxide gas supplied from the carbon dioxide cylinder 61 are mixed in the feed pipe 52 and supplied to the first packed tower 62 from above.

The first packed tower 62 includes a filler 67 inside. In addition, a spray nozzle 65 is provided above the filler 67.
The first packed column 62 is supplied with a gas containing ammonia from a gas feed pipe 52 provided at the upper part of the filler 67, and is supplied with circulating water from a spray nozzle 65 provided at the upper part of the filler 67. It is a co-current contact type packed tower. As the filler 67, the cut nonwoven fabric was filled in the tower.

  Further, a gas feed pipe 53 and a pipe 54 are connected to the lower part of the packing material 67 of the first packed tower 62. The gas feed pipe 53 is connected from the lower part of the first packed column 62 to the upper part of the second packed column 63. Further, the gas supplied from the upper part of the first packed tower 62 and passing through the filler 67 is supplied to the upper part of the second packed tower 63 through the gas feed pipe 53. The pipe 54 is connected to the circulating water tank 64 from the lower part of the first packed tower 62. Further, the circulating water supplied from the spray nozzle 65 passes through the pipe 54 from the lower part of the first packed tower 62 and is collected in the circulating water tank 64.

The second packed tower 63 includes a filler 68 inside. Further, a spray nozzle 66 is provided above the filler 68.
The second packed tower 63 is supplied with a gas containing ammonia discharged from the first packed tower 62 from a gas feed pipe 53 provided at the upper part of the filler 68, and is also provided at the upper part of the filler 68. It is a co-current contact type packed tower to which circulating water is supplied from the spray nozzle 66.
As the filler 68, the cut nonwoven fabric was filled in the tower.
A pipe 55 is connected to the lower part of the second packed tower 63. The pipe 55 is connected to the circulating water tank 64 from the lower part of the second packed tower 63. Further, the gas and the circulating water supplied from the upper part of the second packed tower 63 pass through the pipe 55 and are collected in the circulating water tank 64.

Circulating water is stored in the circulating water tank 64.
A piping 57 is connected to the circulating water tank 64. The pipe 57 supplies the circulating water to the spray nozzle 65 disposed in the upper part of the first packed tower 62 via the pump 69. A piping 58 is connected to the circulating water tank 64. The pipe 58 supplies the circulating water to the spray nozzle 66 disposed in the upper part of the second packed tower 63 via the pump 60.
A piping 56 is connected to the circulating water tank 64. The pipe 56 drives the blower 51, whereby the gas recovered from the lower part of the second packed tower 63 through the pipe 55 into the circulating water tank 64 is discharged to the outside of the circulating water tank 64.

  First, the result of having measured the density | concentration of the ammonia contained in the odor gas discharged | emitted from the composting apparatus generally used and the density | concentration of a carbon dioxide is shown to FIG. FIG. 3A is a graph showing the ammonia concentration (ppm) of the odor gas discharged from the composting apparatus every time (h) and the temperature (° C.) of the pipe from which the odor gas is discharged. Moreover, FIG. 3B is a graph which shows the relationship between the carbon dioxide concentration (ppm) of the odor gas discharged | emitted from the composting apparatus for every time (h), and the temperature (degreeC) of the piping from which odor gas is discharged | emitted. .

As shown in FIG. 3A, ammonia contained in the odor gas discharged from the composting apparatus increased with time from about 1000 ppm at the start of measurement, and stabilized at a concentration of about 2000 ppm. Moreover, as shown to FIG. 3B, the carbon dioxide contained in the odor gas discharged | emitted from the composting apparatus changed the density | concentration between 10000 ppm vicinity and 20000 ppm vicinity. From this result, it was found that carbon dioxide having a concentration about 10 times that of ammonia was discharged from the composting apparatus.
Further, the temperature of the odor gas discharged from the composting apparatus was about 40 ° C. at the start of measurement, but increased with the passage of time and stabilized between 50 ° C. and 60 ° C.

Next, using the deodorizing apparatus 50 shown in FIG. 2, an experiment was conducted in which odorous gas containing ammonia was absorbed by circulating water. The results of this experiment are shown in FIGS.
In this experiment, the diameter of the first packed column 62 and the second packed column 63 was 150 mm as a deodorizing device, and the packing materials 67 and 68 of the packed columns 62 and 63 were cut to a size of 2 cm × 2 cm × 120 cm. A nonwoven fabric was packed into the tower. In addition, 50 L of circulating water was prepared in the circulating water tank 64.
The circulating water was sprayed from the spray nozzles 65 and 66 of the packed towers 62 and 63 at 4.5 L / min.
In addition, the flow rate of ammonia from the ammonia cylinder 59 was set so that the ammonia concentration supplied to the first packed tower 62 would be 2000 ppm on average. Further, the flow rate of the carbon dioxide cylinder 61 was set to be 10 times the flow rate of ammonia from the ammonia cylinder 59. Thereby, the odor gas discharged | emitted from a composting apparatus in pseudo was produced. Carbon dioxide was supplied from a carbon dioxide cylinder 61 so as to have a concentration about 10 times that of ammonia.
In addition, the ammonia concentration and the carbon dioxide concentration were measured using a detection tube at the measurement location of the deodorizing apparatus 50 shown in FIG.

  FIG. 4A is a graph showing the ammonia concentration (ppm) contained in the exhaust gas from the deodorizing apparatus every time (h). FIG. 4B is a graph showing the nitrogen content (ppm) and pH in the circulating water for each time (h).

  As shown in FIG. 4A, the concentration of ammonia exhausted from the pipe 56 is about 200 ppm immediately after the start of the experiment, but increases to 1000 to 1400 ppm over time.

Moreover, as can be seen from the results shown in FIG. 4B, the nitrogen content in the circulating water immediately after the start of the experiment is about 500 to 1000 ppm, but the nitrogen content in the circulating water gradually increases after the start of the experiment, and 12 hours have elapsed. Later, it increased to 4000 ppm or more.
Moreover, as shown in FIG. 4B, by supplying carbon dioxide, ammonia dissolved in the circulating water and carbon dioxide reacted to generate ammonium carbonate or ammonium hydrogen carbonate, and the pH of the circulating water decreased.

Next, the results of continuing the above-described experiment until the ammonia concentration in the intake air and the ammonia concentration in the exhaust gas are the same are shown in FIGS. 5A and 5B.
FIG. 5A is a graph showing the ammonia concentration (ppm) in the odor gas supplied to the deodorization apparatus and the concentration (ppm) of ammonia contained in the exhaust gas every time (h). FIG. 5B is a graph showing the nitrogen content (ppm) and pH in the circulating water for each time (h).

  As shown in FIG. 5A, the ammonia concentration of the odor gas entering the deodorizing device 50 and the ammonia concentration in the exhaust gas from the deodorizing device 50 became the same at about 1500 ppm over time. As shown in FIG. 5B, the nitrogen content in the circulating water increased to about 8000 ppm when the odorous gas entering the deodorizing device 50 and the ammonia concentration contained in the exhaust from the deodorizing device 50 were the same.

  From FIG. 4B and FIG. 5B described above, the nitrogen content in the circulating water is increased to a maximum of about 8000 ppm by reacting carbon dioxide having a concentration of about 10 times the ammonia concentration with ammonia in the odor gas using the packed tower. The result that can be obtained.

Next, FIGS. 6A and 6B show the results when the deodorizing apparatus 50 shown in FIG. 2 is used to dissolve in circulating water using only ammonia.
In this experiment, the flow rate of ammonia from the ammonia cylinder 59 was set so that the ammonia concentration supplied to the first packed column 62 would be 1500 ppm on average. Further, carbon dioxide was not supplied from the carbon dioxide cylinder 61. Except these conditions, it carried out on the same conditions as the experiment which absorbs the above-mentioned ammonia by circulating water.
FIG. 6A is a graph obtained by measuring the ammonia concentration (ppm) and pH contained in the odor gas supplied to the second packed tower 63 every time (h). Moreover, FIG. 6B is a graph which shows the nitrogen content (ppm) of the circulating water discharged | emitted from the 2nd packed tower 63 of the deodorizing apparatus 50 shown in FIG. 2 for every time (h).

As shown in FIG. 6A, immediately after the start of the experiment, the ammonia concentration contained in the odor gas discharged from the second packed tower 63 with respect to the ammonia concentration contained in the odor gas supplied to the second packed tower 63. There is a big difference. However, the ammonia concentration contained in the odor gas supplied to the second packed column 63 became almost the same value.
Immediately after the start of the experiment, the circulating water and the odor gas contacted in the first packed tower 62, so that ammonia was dissolved in the circulating water and the pH in the circulating water continued to rise, and the ammonia became saturated. Even when water and odor gas contact, it is considered that ammonia did not dissolve in the circulating water, and the amount of ammonia contained in the odor gas did not decrease.
As shown in FIG. 6B, the nitrogen content in the circulating water rises in both the first packed column 62 and the second packed column 63 immediately after the start of the experiment. This is considered to mean that the ammonia in the circulating water has become saturated.
As shown in FIG. 5B, the upper limit of the nitrogen content of the circulating water discharged from the first packed column 62 and the second packed column 63 is about 1400 ppm.

From the above experimental results, it is understood that ammonia can be efficiently recovered with water by using carbon dioxide for absorption of ammonia.
When only ammonia was recovered with water without using carbon dioxide, it was saturated in about 8 hours from the start of the experiment, and the nitrogen concentration in the circulating water reached an upper limit at about 1400 ppm. On the other hand, the nitrogen concentration in the circulating water could be increased to 8000 ppm or more by using carbon dioxide having a concentration about 10 times that of ammonia. Moreover, the ammonia concentration contained in the exhaust gas discharged from the deodorizing device can be reduced to about 400 ppm. Therefore, ammonia, which is the main component of the odor component, can be almost removed from the exhaust gas discharged from the deodorizer, and the odor gas can be deodorized.

  The present invention is not limited to the above-described configuration, and various other configurations can be employed without departing from the gist of the present invention described in the claims.

It is a block diagram for demonstrating the deodorizing apparatus of embodiment of this invention. It is a block diagram for demonstrating the deodorizing apparatus used in experiment. A is a graph which shows the ammonia concentration of the odor gas discharged | emitted from the composting apparatus for every hour, and the temperature of piping. B is a graph which shows the carbon dioxide concentration discharged | emitted from the composting apparatus for every hour, and piping temperature. A is a graph showing the ammonia concentration of circulating water in the circulating water tank every hour. B is a graph showing the nitrogen content and pH in the circulating water every hour. A is a graph showing the ammonia concentration in the odor gas supplied to the apparatus for each hour and the concentration of ammonia contained in the exhaust gas. B is a graph showing the nitrogen content and pH in the circulating water every hour. A is a graph obtained by measuring the ammonia concentration and pH contained in the odor gas supplied to the second packed tower every hour. B is a graph which shows the nitrogen content of the circulating water discharged | emitted from the 2nd packed tower 63 of the deodorizing apparatus 50 shown in FIG. 2 for every hour.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,50 Deodorizing apparatus, 11 Composting apparatus, 12 Heat exchanger, 13 1st water tank, 14,62 1st packed tower, 15,63 2nd packed tower, 16 3rd packed tower, 17 1st 2 water tanks, 18, 25, 51 blowers, 19, 21, 23, 60, 69 pumps, 20, 22, 24, 65, 66 spray nozzles, 26, 27, 28, 67, 68 fillers, 31, 33 , 34, 35, 36, 52, 53 Gas pipe, 32, 38, 39, 40, 54, 55, 56, 57, 58 Pipe, 41 Overflow pipe, 42 Exhaust pipe, 43, 44, 45 Circulating water tank, 46, 47, 48 Circulation pipe, 59 Ammonia cylinder, 61 Carbon dioxide cylinder

Claims (4)

A composting device from which odorous gas containing ammonia and carbon dioxide and moisture are discharged;
A heat exchanger that cools the exhaust from the composting device and condenses the moisture;
A deodorizing apparatus comprising: a packed tower that brings water condensed in the heat exchanger into contact with the odor gas.   The deodorizing apparatus according to claim 1, wherein the composting apparatus is a vertical rapid fermentation apparatus.   The deodorizing apparatus according to claim 1, wherein the filler of the packed tower is a cut nonwoven fabric.   The exhaust containing the odor gas and moisture containing ammonia and carbon dioxide discharged from the composting apparatus is cooled by a heat exchanger to condense the moisture, and the exhaust is separated into the odor gas and condensed water. The deodorizing method is characterized in that the separated odor gas and the condensed water are brought into contact with each other in a packed tower.

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