JP6890318B2 - Dust removal system and dust removal method - Google Patents

Description

The present invention relates to a technique for effectively utilizing latent heat in a gas, and to remove dust contained in the gas. In particular, the heat of fermentation generated in the composting process is used to remove dust contained in the exhaust gas of the composting apparatus.

In composting organic matter, fermentation heat equivalent to 550 g (20 MJ) of kerosene is generally generated per 1 kg of organic matter. For example, in the case of pig farming, fermentation heat equivalent to kerosene 26,000 kL / year is generated from the annual excretion amount of 7.88 million tons / year in Japan. However, at present, the generated fermentation heat is discharged into the atmosphere without being used, and research is being conducted to effectively utilize the fermentation heat generated in composting. Fermentation heat recovery methods include a method of directly extracting heat from compost and a method of recovering heat as exhaust gas. The heat of fermentation recovered by the latter method is mainly used for heating water and air via a heat exchanger installed in the passage through which the exhaust from the composting apparatus flows. The applicant can increase the milk yield by using the water heated by the heat of fermentation (warm water) as drinking water for milking cows, and reduce the heating cost by using the hot water as a heat source for heating the floor of the delivery piggery. We are demonstrating the economic benefits of using heat.

Conventionally, the recovery of fermentation heat in a composting apparatus has been previously studied in a suction-ventilated composting apparatus. In the suction-ventilation type composting device, the compost material has a relatively high moisture content and the ventilation speed is slow, so that dust of the compost material is unlikely to be generated. In addition, when dust is generated, the air suction hole at the bottom of the compost fermenter where the compost material is deposited is blocked. As described above, in the suction-ventilation type composting device, since the dust content in the exhaust is low, the heat exchanger provided in the exhaust passage is hardly blocked by the dust. Therefore, it is not necessary to take measures to remove dust from the exhaust gas in the suction-ventilation type composting device. On the other hand, in a closed vertical composting device that is widely used mainly for small and medium-sized livestock and can recover fermentation heat relatively easily, dust is likely to be generated because manure is mechanically agitated and forcibly aerated in the closed device. .. If the dust content in the exhaust is high, the heat exchanger provided in the exhaust passage will be blocked by the dust, resulting in a decrease in heat exchange efficiency and leakage of a foul odor from the exhaust passage. Therefore, a water-washing type dust remover (for example, Patent Document 1) and installation of a cage-shaped filter on an exhaust pipe (for example, Patent Document 2) have been devised.

Japanese Unexamined Patent Publication No. 11-128666 Japanese Unexamined Patent Publication No. 2005-126308

However, the flush type dust remover is expensive as an accessory of the manure treatment facility and requires regular maintenance, which imposes a heavy burden on cost and management. In addition, although it is inexpensive to install a cage-shaped filter in the exhaust pipe, frequent maintenance is required because the filter portion is blocked by dust, which imposes a heavy burden on management. Blockage of the filter portion can be prevented by removing dust with a spray cleaning device or the like, but there is a problem of high cost. As described above, the conventional dust removal measures have a large cost and management burden, and have not been widely used.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dust removal system and a dust removal method that reduce the burden of introduction and management.

Dust system according to the present invention, a closed vertical composting fermentation tank which performs composting process with forced aeration from the bottom of the compost material to be introduced from the top of the closed compost fermentation tank while mechanically stirred, the sealing An exhaust passage that guides the gas of the high heat source generated in the vertical compost fermenter from the lower part in the vertical direction to the upper part in the vertical direction, and an exhaust passage that is arranged in the middle of the exhaust passage and is generated in the process of utilizing the latent heat of the gas. A heat exchanger for exchanging heat with a low heat source body via plate fins arranged so that condensed water drips is provided, and the gas passes from the lower part in the vertical direction to the upper part in the vertical direction with respect to the plate fins. heat exchange is performed when, and dew condensation water generated dust contained in the gas to adhere to the lower of the plate fins in the plate fins are removed by the dropwise addition of the surface of the plate fins, It is characterized by that.

Dust removal method according to the present invention occurs in a closed vertical composting fermenter of forced ventilation to composting process from the bottom of the compost material to be introduced from the top of the closed compost fermentation tank while mechanically stirred high The gas of the heat source is guided from the lower part in the vertical direction to the upper part in the vertical direction, and is arranged in the middle of the induction path of the gas of the high heat source, and condensed water generated in the process of utilizing the latent heat of the gas of the high heat source drops. In a heat exchanger that exchanges heat with a low heat source body through plate fins arranged so as to perform heat when the gas of the high heat source passes from the lower side in the vertical direction to the upper side in the vertical direction with respect to the plate fins. exchange is performed, and is removed by condensation water dust contained in the gas of the high heat source to adhere to the lower of the plate fins produced in the plate fins dripping the surface of the plate fin, it It is characterized by.

According to the present invention, it is possible to solve the above problems and perform dust removal to reduce the conventional burden.

It is a block block diagram which shows the dust removal system of embodiment of this invention. It is a figure explaining the dust removal action in the dust removal system of embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block configuration diagram showing a dust removal system 100 according to an embodiment of the present invention. The dust removal system 100 of the embodiment of the present invention includes a compost fermenter 10, an exhaust passage 20, a first heat exchanger 30, a second heat exchanger 35, a first discharge port 40, and a second discharge port 45. It is provided in the process of recovering the heat of compost fermentation and utilizing the heat in the facility having the above. The dust removal system 100 of the present invention is preferably applied to a closed-type composting facility in which the exhaust H generated in the composting process of the compost raw material T can be directly recovered without being diluted with the outside air. It is applicable to automatic composting equipment such as screw type and facilities that cover the accumulated compost with curtains and collect the warm and moist air above the compost. Here, a closed vertical composting facility will be described as an example.

The compost fermenter 10 is a closed vertical composting device. The compost fermenter 10 mechanically stirs and forcibly agitates the compost raw material T input from the upper part of the closed compost fermenter 10 to perform composting treatment. Then, the air blown from the lower part of the compost fermenter 10 to the inside is exhausted from the upper part of the compost fermenter 10 through the compost. The exhaust H exhausted at this time includes fermentation heat generated in the composting step, and has a high temperature (50 ° C. or higher) and a high humidity (about 100% RH).

The exhaust passage 20 is a pipe arranged so that the exhaust H is once guided downward in the vertical direction from the upper part of the compost fermenter 10 and then turned back and directed upward in the vertical direction. Then, in the exhaust passage 20, the first heat exchanger 30 is arranged in the middle of the exhaust passage 20 in which the exhaust H flows from the lower part in the vertical direction to the upper part in the vertical direction. In the dust removal system 100 of the present invention, the exhaust passage 20a is provided with a dust removal passage 20a that flows from the lower part in the vertical direction to the upper part in the vertical direction so that the exhaust H reverses in the direction of gravity, and the first heat exchange occurs in the dust removal passage 20a. It is characterized in that a vessel 30 is provided. The exhaust passage 20 of the present embodiment is further piped so as to guide the exhaust H that has passed through the first heat exchanger 30 from the upper part in the vertical direction to the lower part in the vertical direction, and is on the passage downstream of the dust removal passage portion 20a. A second heat exchanger 35 is arranged in the room. Further, the exhaust passage 20 is provided with a first exhaust port 40 below the first heat exchanger 30 and a second exhaust port 45 below the second heat exchanger 35. Then, the exhaust H that has passed through the second heat exchanger 35 is guided to a deodorizing device that deodorizes the exhaust H through the exhaust passage 20.

The first heat exchanger 30 and the second heat exchanger 35 are heat exchangers that exchange heat of the fluids via heat transfer bodies arranged between fluids having different temperatures, and are so-called partition type. It is a heat exchanger. For the first heat exchanger 30 and the second heat exchanger 35 according to the present embodiment, for example, a orthogonal flow plane fin type heat exchanger is used. The first heat exchanger 30 is provided in the dust removal passage portion 20a of the exhaust passage 20. In the first heat exchanger 30, the exhaust H is introduced from below in the vertical direction, and the exhaust H is introduced between the exhaust H (high heat source fluid) and the outside air (low heat source fluid) via the plate fins which are heat transfer bodies. Heat exchange is performed to utilize the heat of fermentation (latent heat). At this time, dust Ta contained in the exhaust gas H adheres to the plate fins of the first heat exchanger 30. Further, dew condensation occurs on the plate fins of the first heat exchanger 30 due to heat exchange with the outside air having a temperature lower than that of the exhaust gas H. The dust removal system 100 of the present invention is characterized in that the plate fins of the first heat exchanger 30 function as a dust removal filter having an action of removing dust Ta adhering to the plate fins by the dew condensation water Ha generated by the heat exchange. The outside air heated via the first heat exchanger 30 is introduced into the compost fermenter 10. The second heat exchanger 35 is provided in the exhaust passage 20 downstream of the dust removal passage portion 20a. In the second heat exchanger 35, the exhaust H is introduced from above in the vertical direction, and heat exchange between the exhaust H (high heat source fluid) and water (low heat source fluid) is performed via the plate fins. The exhaust gas H at this time contains almost no dust Ta, and the plate fins of the second heat exchanger 35 are not blocked by the dust Ta. It is the first heat exchanger 30 provided mainly in the dust removing passage portion 20a that has the dust removing effect. The water (warm water) heated via the second heat exchanger 35 is provided as drinking water for livestock and as a heat source for floor heating of the piggery.

The first discharge port 40 and the second discharge port 45 allow the dew condensation water Ha (in the case of the first discharge port 40, together with the dust Ta) generated in the first heat exchanger 30 and the second heat exchanger 35 to be exhausted through the exhaust passage 20. A water lid is provided at the end of the exhaust passage 20 located below each heat exchanger so as to discharge the water to the outside of the heat exchanger, and the water is sealed by the drain trap structure. The height of the water column of the water column of the water sealing part of the drain trap structure is 10 cm or more if the static pressure and the air volume of the composting device of the present embodiment are taken into consideration in consideration of the balance between the pressure inside the pipe of the exhaust passage 20 and the atmospheric pressure. It is enough to secure it. If the concentration of ammonia gas in the exhaust gas H is high and the ammonia nitrogen in the condensed water Ha exceeds the discharge standard concentration in terms of nitrate nitrogen concentration, it is necessary to guide it to a sewage treatment facility or a deodorizing device. ..

Next, FIG. 2 describes the dust removing action in the dust removing system of the present invention. Specifically, the dust removing action in the dust removing passage portion 20a, the first heat exchanger 30, and the first discharging port 40 of the exhaust passage 20 according to the embodiment of the present invention will be described in detail.

The compost fermenter 10 of the present embodiment is a closed vertical composting device, and a large amount of compost fermented and dried by stirring and aeration is scattered as dust Ta in the upper space inside the device. Therefore, the exhaust H exhausted from above the compost fermenter 10 to the exhaust passage 20 contains a large amount of dust Ta. Therefore, when the exhaust H passes through the first heat exchanger 30 provided in the dust removal passage portion 20a of the exhaust passage 20, a large amount of dust Ta in the exhaust adheres below the plate fin 31 on the exhaust introduction port side. Here, the plate fins 31 through which the exhaust H of the first heat exchanger 30 passes are provided so that the exhaust H flows from the lower side in the vertical direction to the upper side in the vertical direction, similarly to the dust removal passage portion 20a. Therefore, the dew condensation water Ha of dew condensation generated on the surface of the plate fin through which the exhaust H passes due to heat exchange drops, and the dust Ta is washed downward from the exhaust introduction port side. Further, the dust Ta is mixed with the condensed water Ha and becomes mud, and falls downward due to the gravity of the mud itself. In this way, the plate fins 31 of the first heat exchanger 30 function as a dust removal filter, and the dust Ta is removed from the exhaust inlet side of the plate fins 31 by the dew condensation water Ha, and the exhaust H is removed against the direction of gravity. By introducing the heat exchanger 30 into the heat exchanger 30, dust Ta is removed from the exhaust by gravity, so that the first heat exchanger 30 is prevented from being blocked. Further, since the plate fin 31 is maintained in a clean state by the dew condensation water Ha, it is possible to suppress the deterioration of the function of the dust removal filter, that is, the deterioration of the dust removal effect. Then, the removed dust Ta and dew condensation water Ha are discharged to the outside from the first discharge port 40 through the dust removal passage portion 20a.

If the compost fermenter 10 is in a normal fermentation state, the relative humidity of the exhaust H is always close to 100% RH, and even if the heat loss is such that the exhaust temperature drops a little, a sufficient amount of dew condensation can be removed by heat exchange. Water Ha is constantly generated. A fan may be provided for introducing the outside air in order to ensure the generation of condensed water Ha in the first heat exchanger 30. Further, the compost fermenter 10 was mentioned as the source of the exhaust H, but it is a gas containing dust and latent heat, and is generated to generate a gas that is a high heat source that generates dew condensation water in the process of utilizing the latent heat in heat exchange. If it is a source, the dust removal system of the present invention can be applied.

Further, the orthogonal flow plane fin type heat exchanger is mentioned as the first heat exchanger 30, but the present invention is not limited to this. Any heat exchanger having a structure capable of functioning as a dust removal filter may be used. That is, by introducing the exhaust H (high heat source fluid) from the lower part in the vertical direction to the upper part in the vertical direction, the dew condensation water Ha generated by the heat exchange can be discharged from the exhaust introduction port side (high heat source fluid introduction side). It is applicable if it is a switch.

(Effect of embodiment)
According to the dust removal system of the embodiment of the present invention, it is possible to provide dust removal with reduced cost and management burden by using the heat of compost fermentation from the composting apparatus. Specifically, by recovering heat from fermentation generated in the composting process as exhaust heat, heat utilization such as heating of incoming air by heat of fermentation and acquisition of hot water becomes possible through a heat exchanger. -Although the utilization cycle has been established, in composting equipment of the type with a large amount of dust in the exhaust, the dew condensation water generated in the heat exchanger and the dust in the exhaust are mixed and turned into mud, and the mud blocks the heat exchanger. There was a problem to do. On the other hand, in the past, a dust remover was separately provided to take measures, but the present invention utilizes a fermentation heat recovery / heat utilization cycle to generate dew condensation water from high temperature and high humidity exhaust by heat exchange. I used it. The dust removal system of the present invention is a heat exchanger on an exhaust passage that guides exhaust from a composting device (gas generation source) (gas of a high heat source including latent heat and dust) from downward in the vertical direction to upward in the vertical direction. The effect of the dust removal function can be obtained by using the plate fins (heat transfer body) of the heat exchanger as a dust removal filter. There is no need to provide. As described above, since the dust removal effect can be obtained only by changing the layout of the existing exhaust passage piping and the heat exchanger, it is possible to provide an inexpensive dust removal system and a dust removal method that do not require maintenance.

Further, the conventional exhaust passage is mainly composed of a passage that guides the exhaust from the upper side in the vertical direction to the lower side in the vertical direction and a passage that guides the exhaust in the horizontal direction with respect to the ground, and a heat exchanger is installed on the passage. After arranging them, the inventors of the present invention focused on the dew condensation water generated in the heat exchanger, and reached the dust removal system and the dust removal method of the present invention for removing the dust adhering to the plate fins using the dew condensation water. It was. The exhaust passage of the present invention has a passage for guiding exhaust from the lower part in the vertical direction to the upper part in the vertical direction, and an internal plate fin is provided on the passage so as to guide the exhaust from the lower part in the vertical direction to the upper part in the vertical direction. Place a heat exchanger. With such a layout, the plate fins of the heat exchanger are constantly washed from top to bottom by the dew condensation water generated by the heat exchange, and the dust that has become muddy by the dew condensation water falls downward due to gravity. Further, since the exhaust gas is introduced from below the heat exchanger, the dust is removed from the exhaust introduction port side of the heat exchanger at the time of dust removal. Therefore, it is possible to remove the dust from the exhaust by gravity before the dust reaches the heat exchanger, and the heat exchanger is placed on the passage that guides the exhaust from the upper vertical direction to the lower vertical direction. The amount of dust that has become muddy due to condensed water passing through the inside of the plate fin (internal residence time) can be significantly reduced as compared with the case where the dust is formed. Further, since a drain trap structure discharge port is provided below the heat exchanger, dust, mud, and condensed water that have fallen due to gravity can be quickly discharged to the outside of the exhaust passage. Therefore, the adhesion of dust to the plate fins is suppressed, and the heat exchanger can be prevented from being blocked.

Further, according to the present invention, dew condensation water generated from the exhaust gas itself and gravity can effectively remove dust by heat exchange, and heat exchange and dust removal can be performed at the same time. Therefore, it is possible to prevent the heat exchanger from being blocked by operating the composting apparatus having a high dust content in the exhaust gas for a long period of time as in the present embodiment, and to reduce the efficiency of the fermentation heat recovery / heat utilization cycle. It is possible to prevent the occurrence of problems.

As described above, dust removal using the heat of compost fermentation can be stably performed together with heat exchange because dew condensation water is always generated when the compost is in a fermented state. Therefore, it is possible to promote the promotion of utilization.

It goes without saying that the present invention is not limited to the above-described embodiment, and can be implemented in various aspects as long as it belongs to the technical scope of the present invention.

For example, in the above-described embodiment, the composting treatment of livestock waste such as livestock manure has been given as an example, but it can also be applied to general waste treatment and industrial waste. For example, it can be applied to a system that reduces the volume of a large amount of kitchen waste by fermentation treatment or drying treatment using a rotating drum or a horizontal compost fermenter, as well as dust removal in a gas containing dust and latent heat. ..

100 Dust removal system 10 Compost fermenter (gas source)
20 Exhaust passage 20a Dust removal passage (gas guiding means)
30 First heat exchanger (heat exchange means, removal means)
31 Plate fin (heat transfer body)
35 Second heat exchanger 40 First discharge port 45 Second discharge port T Compost raw material Ta Dust H Exhaust Ha Condensation water

Claims (5)

A closed vertical compost fermenter that performs composting treatment by forcibly agitating the compost raw material input from the upper part of the closed compost fermenter from the lower part while mechanically stirring it.
An exhaust passage that guides the gas of the high heat source generated in the closed vertical compost fermenter from the lower part in the vertical direction to the upper part in the vertical direction.
A heat exchanger disposed in the middle of the exhaust passage and exchanging heat with a low heat source body via plate fins arranged so that dew condensation water generated in the process of utilizing the latent heat of the gas drops.
With
Heat exchange is performed when the gas passes into the vertically upward from vertically downward relative to the plate fins, and the dust contained in the gas to adhere to the lower of the plate fins in the plate fin The generated dew condensation water is removed by dropping the surface of the plate fin.
A dust removal system characterized by that. The exhaust passage is provided below the heat exchanger with an exhaust port for discharging the condensed water and dust dripping from the plate fins.
The dust removal system according to claim 1. The discharge port is arranged at a position where the mud mixed with the dust adhering to the lower part of the plate fin and the condensed water can remove the mud that falls downward due to its own weight.
The dust removal system according to claim 2. A second heat exchanger, which is located downstream of the heat exchanger in the induction direction of the gas and is arranged in the middle of the exhaust passage for inducing the gas from the upper side in the vertical direction to the lower side in the vertical direction, is further provided.
Said second heat exchanger to warm the water by heat exchange with water as the gas and the low heat source body, wherein the dust is removed,
The dust removal system according to any one of claims 1 to 3. An enclosed composting fermenter high heat source gas generated in a closed vertical composting fermenter compost material is charged from the top with forced aeration from the bottom while mechanically stirred performs composting process from vertically downward Guide upward in the vertical direction,
Heat with the low heat source body via plate fins arranged in the middle of the induction path of the gas of the high heat source and arranged so that dew condensation water generated in the process of utilizing the latent heat of the gas of the high heat source drips. In the heat exchanger to be replaced
Heat exchange was performed when the gas of the high heat source passed through the plate fins from the lower part in the vertical direction to the upper part in the vertical direction, and was contained in the gas of the high heat source adhering to the lower part of the plate fins. condensation dust was generated in the plate fins are removed by the dropwise addition of the surface of the plate fins,
A dust removal method characterized by that.

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