JP4784839B2 - Processing equipment for methane fermentation of organic waste - Google Patents

Description

  The present invention relates to a contaminant removal apparatus for treating organic waste with methane fermentation.

  Organic waste such as waste from crop processing plants, waste from marine products processing plants, dredging and sewage sludge contains sand and metal pieces. It is desirable to remove it.

Patent Document 1 discloses an apparatus for refining organic waste including plastics such as garbage, which has been previously removed with trommel in a tempering tank in order to treat it by methane fermentation. Has been. As described in FIG. 1 and paragraphs [0045] to [0053] of Patent Document 1, this apparatus includes a tempering tank (storage tank) 3 and a separation tank (contaminant removing means) connected to the bottom thereof. ) 8 The top of the tempering tank 3 is provided with an inlet for supplying organic waste (crushed material) and water from the water supply pipe 21, and an outlet is provided at the bottom, and the input organic waste is disposed inside. A stirrer (stirring means) 4 is provided for stirring the slurry-like mixture of water and water to cut organic waste. A transfer pipe 7 connected to the separation tank 8 is connected to the discharge port of the tempering tank 8. The organic waste slurry placed in the separation tank 8 forms a vortex there, and collects heavy objects such as sand and metal pieces at the funnel-shaped bottom 9 and withdraws them from the contaminant discharge pipe 12 connected to the lower end. Is issued. A discharge pipe 16 is connected to a position 2/3 downward from the upper end of the separation tank. The discharge pipe 16 branches in the middle, one for methane fermentation and the other for the tempering tank via the circulation pipe 19. 3 is sent back. The paragraph [0090] also shows that a circulating pump having a crushing function is used in the middle of the circulation pipe 19.

  A continuous type using a drum screen and a screw screen as a contaminant removing means is also disclosed.

JP 2000-61432 A

In the above-described conventional technology, there is a problem in the separation of organic waste and impurities in the separation tank and the adjustment of supply and carry-out of organic waste.
That is, in separating organic waste and contaminants in the separation tank, the contaminant removal means uses a liquid cyclone type separation tank in the case of batch processing, and a drum screen in the case of continuous processing. However, in the former case, when the specific gravity of the organic waste is larger than that of water, the organic waste is separated together with the contaminants, and it becomes difficult to separate the organic waste and the contaminants. For example, the specific gravity of potato is 1.1. On the other hand, in the latter case, organic waste having a diameter similar to or larger than that of the contaminants is separated together with the contaminants, so that the loss of the methane fermentation raw material is large.

Next, regarding the adjustment of supply and unloading, the organic waste supplied to the tempering tank is carried by a conveyor, so it is difficult to quantitatively supply it, and it is also difficult to grasp the accurate supply amount. It is.
On the other hand, a carry-out pump is used to carry out the conditioned material from which impurities have been separated. The amount of conditioned material carried by the carry-out pump depends on the supply amount of organic waste supplied as described above. It is extremely difficult to control.

  Furthermore, in the above technical field, since the organic waste is crushed in the presence of impurities such as stones and metals, it is also a problem that the crushing blade is damaged.

The present invention has been made to solve the above problems, and has the following characteristics.
The waste removal means is an upward flow type sedimentation (gravity) separation tank, and the upward flow rate is set to be higher than the sedimentation rate of organic waste and less than the sedimentation rate of contaminants. Can be separated continuously with high accuracy.
By using an overflow type of means for carrying out the conditioned material from which contaminants have been separated, it becomes unnecessary to control the carry-out amount of the carry-out pump in accordance with the supply amount of organic waste.
A crushing pump is used as a circulating means for circulating the slurry flowing out from the upward flow type sedimentation (gravity) separation tank to the lower part of the upward flow type precipitation (gravity) separation tank, and the amount of circulation is organic waste. It was possible to make slurry tempering without providing a separate tempering means by repeatedly passing it through a crushing pump.
The present invention is obtained by the improvement as described above, and in the processing facility for methane fermentation of organic waste, the impurities are obtained from a slurry mixture of organic waste mixed with impurities and water. and an upflow type settling tank for separating the overflow type of the unloading means for unloading the slurry-like mixture in which the contaminants are separated into methane fermentation tank, the outflow slurry from said upflow type settling tank A circulating means for circulating to the lower part of the upward flow type sedimentation separation tank via the overflow type discharge means, and an organic substance in which the impurities are mixed in the top of the upward flow type sedimentation separation tank The present invention provides a treatment facility for methane fermentation of organic waste, characterized in that waste and water introduction means are arranged.

  According to the present invention, even if the specific gravity of the organic waste is greater than that of water, it is possible to reliably separate the organic waste from the foreign matters such as stones and metals. It is also easy to control the carry-out amount according to the supply amount. Furthermore, since the impurities can be reliably separated before crushing the organic waste, the crushing blade is not damaged.

The processing apparatus for methane fermentation of this invention consists of an upflow type sedimentation tank and an overflow type carrying-out means.
The upward flow settling tank separates the impurities from a slurry mixture of organic waste mixed with impurities and water, and the organic waste mixed with the impurities and water are mixed at the top. The introduction means is provided with a means for extracting settled impurities at the bottom, and further provided with an outlet and an introduction port for circulating the slurry-like mixture between the overflow-type carrying means.

  The shape of the tank body is usually a cylinder, but may be a square tube, or may be a different diameter tube having an enlarged upper or lower part. The L / D between the inlet and the outlet for circulating the slurry mixture in the tank body is suitably about 2D to 4D. It is preferable not to provide a stirrer or the like in the interior in order not to disturb the upward flow.

  The introduction port for introducing organic waste and water at the top may be provided separately, or a single introduction port may be used. It is preferable that the supply amount of the organic waste can be adjusted by a quantitative feeder or the like in the supply path of the organic waste, and a quantitative supply pump or the like in the water supply pipe.

  The lower part of the tank body below the inlet for circulating the slurry-like mixture is used as a storage tank for settled impurities. The bottom is provided with an extraction port for this foreign matter. A rotary valve or the like may be provided at the extraction port so that impurities can be extracted intermittently or continuously.

An outlet for circulating the slurry-like mixture between the overflow-type carrying-out means is provided in the upper part of the tank body and an inlet is provided in the lower part, and an upward flow is formed therebetween.
The overflow type unloading means discharges an amount corresponding to the supply amount out of the system without controlling the unloading amount of the unloading pump. A preferred embodiment of the overflow type carry-out means is a buffer tank having an overflow means such as an overflow weir or a telescopic valve at the top. The buffer tank is provided with an inlet and an outlet for the slurry-like mixture, both of which are suitable at the bottom of the tank.

  The circulation means circulates the slurry flowing out of the upward flow type sedimentation separation tank to the lower part of the upward flow type sedimentation separation tank via the overflow type carry-out means. It consists of a pump. The amount of circulation can be controlled by controlling the rotational speed of this pump. If a crushing type pump is used for the circulation pump, the organic waste can be repeatedly crushed to be finer, and more preferable as a methane fermentation raw material.

  When organic waste is processed using the above methane fermentation treatment facility, first, the supply amount of organic waste and water is adjusted to obtain a preferable mixing ratio.

  This slurry-like mixture is put into a settling tank and circulated by operating a circulation pump. In principle, the slurry-like mixture is charged continuously, but it may be intermittent or a batch system.

In circulation, the sedimentation speed is first obtained. In addition to the general formula, there are Stokes' formula, Allen's formula, Newton's formula, etc., but the Allen's formula is appropriate when the Reynolds number is about 10 ⁰ to 10 ³ . Therefore, the Allen equation is used here. The Allen equation is:

First, taking potato as an organic substance as an example, the sedimentation speed was calculated by the above formula, and a sedimentation speed of 4.99 cm / s was obtained at a particle diameter of 1.80 cm.
The numerical value of each factor used as the premise of calculation is as follows.
Ray nozzle number Re 1.80
Gravity acceleration g 980cm / s ²
Particle size d 1.80cm
Viscosity coefficient μ 5.00g / cm · s
Same viscosity coefficient γ 5.00cm ² / s
Resistance coefficient CD 9.44
Particle density ρ ^s 1.10 g / cm ³
Liquid density ρ 1.00 g / cm ³
Sedimentation speed wb 4.99 cm / s

Next, as an example of impurities, the sedimentation rate of stone was calculated to obtain a sedimentation rate of 5.39 cm / s with a particle size of 0.30 cm.
Ray nozzle number Re 0.32
Gravity acceleration g 980cm / s ²
Particle size d 0.30cm
Viscosity coefficient μ 5.00g / cm · s
Same viscosity coefficient γ 5.00cm ² / s
Resistance coefficient CD 22.24
Particle density ρ ^s 2.65 g / cm ³
Liquid density ρ 1.00 g / cm ³
Sedimentation speed wb 5.39 cm / s
Thus, the sedimentation rate was calculated by changing the particle size of potato and stone, and the following results were obtained. This is shown in FIG.

From the above results, it is possible to efficiently remove the stones by setting the upward flow speed to be slower than the sedimentation speed of the stone and faster than the sedimentation speed of the organic matter.
In the present invention, the circulation flow rate Qr is set to be larger than the input flow rate Qin of the slurry-like mixture of organic waste.
For example, if the circulation flow rate Qr is 5 times the input flow rate Qin, it can be circulated five times on average, and if a crushing type is used for the circulation pump, it can be crushed five times.

  A processing facility having the configuration shown in FIG. 1 was produced. This processing equipment is composed of a separation tower which is an upward flow settling tank and a buffer tank which is an overflow discharge means. The separation tower has a cylindrical shape as a whole, and the bottom has a funnel shape. At the top of the separation tower, an organic substance introduction pipe is disposed, and a dilution water supply pipe is connected to the introduction pipe. On the other hand, the funnel-shaped bottom part is provided with a foreign substance extraction outlet which is a foreign substance. The outlet of the slurry mixture is provided at the upper side of the separation tower, and the inlet of the circulated slurry mixture is provided at the lower part.

The buffer tank is box-shaped, and an upper part is provided with an overflow port for the slurry-like mixture, and a lower part is provided with an inlet and an outlet for circulating slurry-like mixture.
One end of the circulation line, which is a circulation means, is connected to the outlet of the upper part of the separation tower, and the other end is connected to the inlet of the lower part of the separation tower via the inlet and outlet of the buffer tank. A circulation pump having a crushing function is attached in the middle of the circulation line.

  Potatoes, which are organic waste to be supplied, are first roughly crushed by a biaxial crusher, and the particle size is 10 mm from the width of the mesh. The stones to be separated and removed were those with a diameter of 5 mm or more. Therefore, the ascending flow velocity V was set to 5.00 cm / s from the above calculation. Thereby, stones with a diameter of 3 mm or more settle, and organic waste with a diameter of 18 mm or less can be circulated.

The input flow rate Qin of the slurry-like mixture was set to 0.16 m ³ / min, and the circulation flow rate Qr was set to 3 times that. Since the discharge flow rate Qout of the slurry-like mixture is the same as the input flow rate Qin, the ascending flow rate is twice the input flow rate Qin, that is, 0.32 m ³ / min.

Then, in order to obtain an ascending flow velocity of 5.00 cm / s, the ascending tube area is 0.11 m ² , and thus the tube diameter is 0.37 m. Therefore, the tube diameter of the separation tower is set to 0.37 m.

  The total length of the cylindrical part of the separation tower was 1600 mm, the outlet was 1500 mm from the lower end of the cylindrical part, and the inlet was 200 mm. The volume of the buffer tank was about 6 times the separation column volume. When potatoes with sand were roughly crushed, water was added at a ratio of 1: 1, and this was treated with the above processing equipment, potatoes could be obtained in a yield of 100%, and most of the stones could be removed. .

  Since the processing apparatus of the present invention can efficiently separate foreign substances such as stones even if the organic waste has a specific gravity greater than that of water, it is useful as equipment for preparing potato fermentation raw materials such as potato.

It is a figure which shows typically the methane fermentation processing equipment of this invention. It is a graph which shows the relationship between the particle diameter of a stone and a potato, and a sedimentation rate.

Claims (2)

In a processing facility for methane fermentation of organic waste, an upward flow type sedimentation separation tank for separating the contaminant from a slurry-like mixture of organic waste mixed with stone or metal contaminant and water, and the contaminant a buffer tank provided with a spilled flow means for unloading the slurry-like mixture objects are separated into the methane fermentation tank, the outflow slurry from said upflow type settling tank, a buffer tank provided with the overflowing stream means One end to be circulated to the lower part of the upward flow type sedimentation separation tank is connected to the outlet of the upper part of the separation tank, and the other end is an inlet and outlet provided at the lower part of the buffer tank provided with the overflow means. A circulation line connected to the inlet of the lower part of the separation tank through the outlet, and a circulation pump is installed in the middle of the circulation line, and the organic matter in which the impurities are mixed in the top of the upward flow type sedimentation separation tank Waste and water Methane fermentation treatment facilities organic waste, characterized in that it has disposed guide means The treatment facility for methane fermentation of organic waste according to claim 1, wherein the circulation pump has a function of crushing the circulation.

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