JP7601667B2 - Reaction apparatus and reaction method - Google Patents

Description

The present invention relates to a reaction apparatus and a reaction method. In particular, the present invention relates to a reaction apparatus and a reaction method that form a fluidized bed.

A reactor is known in which particles packed in a tank are fluidized by a fluid (gas or liquid) to form a fluidized bed, and a reaction takes place through contact between the fluid and the particles. Reactors that form fluidized beds are able to suppress clogging and increases in pressure loss compared to reactors that form fixed beds, and are used in a wide range of fields, including the manufacture of chemical compounds, drying of particles, and separation by adsorption and adhesion of dissolved substances in fluids.

Patent Document 1 describes a reactor that forms a fluidized bed by providing partition walls in the upper and lower directions inside the tank, which increases the mixing efficiency of the fluid and particles and prevents the particles from jumping out.

Japanese Patent Application Publication No. 2-75304

As described in Patent Document 1, in a reactor that forms a fluidized bed, the fluidized bed is generally formed using one type of particles.
On the other hand, in the case of a reaction system that requires multiple reaction steps as a reaction caused by contact between a fluid and particles, multiple reaction devices in which particles suitable for each reaction step are selected must be provided, which results in a problem of an increase in the overall size of the device.

Here, when multiple reaction steps are to be carried out in a single-tank reaction apparatus in order to save space in the reaction apparatus, the partition wall structure described in Patent Document 1 fluidizes the particles as a whole, but it is difficult to fluidize multiple particles with different properties (particularly fluidity) as a whole. This makes it impossible to maintain uniform fluidity within the reaction apparatus, and there is a problem in that the reaction steps cannot be carried out appropriately.

The objective of the present invention is to provide a reaction apparatus and a reaction method that utilize a fluidized bed formed by multiple types of particles and that can maintain uniform fluidity.

As a result of intensive research into the above-mentioned problems, the present inventors have found that in a reaction apparatus forming a fluidized bed in which two or more types of particles having different minimum fluidization velocities are fluidized, uniform fluidity can be maintained within a single vessel by providing a plurality of regions through which fluid passes at different flow velocities and setting the flow velocity in each region within a range according to the properties of the particles, thereby completing the present invention.
That is, the present invention relates to the following reaction apparatus and reaction method.

In order to solve the above problems, the reaction apparatus of the present invention is a reaction apparatus that forms a fluidized bed by fluidizing two or more types of particles having different minimum fluidization velocities, and is characterized in that it comprises a first flow velocity region where a fluid passes at a first flow velocity and a second flow velocity region where a fluid passes at a second flow velocity, and the first flow velocity is higher than the minimum fluidization velocity of the first particles and the second particles, and the second flow velocity is lower than the minimum fluidization velocity of the first particles and higher than the minimum fluidization velocity of the second particles.
According to the reactor of the present invention, in a reactor in which two or more kinds of particles are fluidized to form a fluidized bed, by providing a plurality of regions of fluid flow speed according to the properties of the particles (minimum fluidization speed), a fluidized bed for each particle is formed in the reactor, and it becomes possible to maintain uniform fluidity as a whole reactor. In addition, since a plurality of reaction processes can be carried out in one tank, it becomes possible to save space as a reactor and improve processing efficiency.

In one embodiment of the reaction apparatus of the present invention, the difference in specific gravity between the first particles and the second particles is 1.2 times or more.
According to this feature, it is possible to form a layered state in which a layer made of first particles and a layer made of second particles are formed without requiring any special operations, making it easy to form and maintain the first flow rate region and the second flow rate region.

In one embodiment of the reaction apparatus of the present invention, the first particles are activated carbon, and the second particles are granules.
According to this feature, granules for anaerobic treatment and activated carbon, which has excellent functions as an adsorbent for removing inhibitors of anaerobic treatment and as a carrier for attaching and supporting some anaerobic microorganisms, can be combined and used in one tank. By using this reactor, anaerobic treatment can be carried out even with one tank, making it possible to save space for equipment related to anaerobic treatment. In addition, by applying this reactor to anaerobic treatment, inhibition of anaerobic treatment caused by inhibitors can be reduced, making it possible to improve the efficiency of anaerobic treatment.

The reaction method of the present invention for solving the above problems is a reaction method using a fluidized bed in which two or more types of particles having different minimum fluidization velocities are fluidized, and is characterized in that a first flow velocity region in which a fluid passes through the fluidized bed at a first flow velocity and a second flow velocity region in which the fluid passes through at a second flow velocity are formed, and the first flow velocity is greater than the minimum fluidization velocity of the first particles and the second particles, and the second flow velocity is smaller than the minimum fluidization velocity of the first particles and greater than the minimum fluidization velocity of the second particles.
According to the reaction method of the present invention, in a reaction using a fluidized bed in which two or more types of particles are fluidized, by providing multiple regions of fluid flow speed according to the properties of the particles (minimum fluidization speed), a fluidized bed is formed for each particle, and it becomes possible to proceed with the reaction while maintaining uniform fluidity. In addition, multiple fluidized beds can be formed in one tank, making it possible to proceed with multiple reaction steps. This makes it possible to save space in the equipment related to the reaction and improve the processing efficiency.

The present invention provides a reaction apparatus and a reaction method that utilize a fluidized bed formed by multiple types of particles and that can maintain uniform fluidity.

FIG. 1 is a schematic explanatory diagram of a reaction apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram showing the relationship between the minimum fluidization velocity of the first particles and the second particles, and the first flow rate and the second flow rate used in the reaction apparatus according to the first embodiment of the present invention. FIG. 1 is a schematic diagram illustrating anaerobic treatment using a reaction apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a reaction apparatus according to a second embodiment of the present invention. FIG. 1 is a schematic diagram of a reaction apparatus according to a third embodiment of the present invention.

Below, the embodiments of the reaction apparatus and reaction method according to the present invention will be described in detail with reference to the drawings. Note that the reaction apparatus described in the embodiments is merely an example for explaining the reaction apparatus according to the present invention, and is not limited thereto. Also, the reaction method described in the embodiments is merely an example for explaining the reaction method using the reaction apparatus according to the present invention, and is not limited thereto.

The reaction apparatus and reaction method of the present invention are used for all reactions involving contact between fluids and particles. The reaction apparatus and reaction method of the present invention are particularly suitable for use in the anaerobic treatment of wastewater containing organic matter.

The fluid in the present invention may be either a liquid or a gas, or may be both a liquid and a gas. That is, the reaction apparatus and reaction method of the present invention may utilize any of a solid-liquid two-phase flow, a gas-liquid two-phase flow, or a solid-gas-liquid three-phase flow. The fluid in the present invention may be introduced into the reaction apparatus of the present invention as a material to be treated that contains a raw material, a medium, or a substance to be treated.
For example, the fluid in the present invention may be a known combination of raw materials such as a combination of multiple types of gases that serve as raw materials for monomers (a combination of acetylene gas and acetic acid vapor).
In addition, the fluid in the present invention may be, for example, air that functions as a medium for mixing and drying particles. In addition to room temperature air, high-temperature gas such as combustion gas may be used to increase the drying efficiency.
Furthermore, examples of the fluid in the present invention include wastewater containing organic matter as a treatment target. Examples of wastewater containing organic matter to be treated include industrial wastewater discharged from various factories such as food factories, chemical factories, and paper and pulp factories, and domestic wastewater such as sewage. Although wastewater containing organic matter is not limited to these, wastewater containing organic matter that can be biologically treated under anaerobic conditions is particularly preferred as a fluid in the present invention. Examples of such wastewater include organic wastewater containing livestock manure and sludge (excess sludge).
Hereinafter, the fluid in the present invention will be described mainly as a material to be treated (wastewater containing organic matter), but is not limited thereto.

[First embodiment]
FIG. 1 is a schematic diagram of a reaction apparatus according to a first embodiment of the present invention.
1, the reaction apparatus 1A in this embodiment includes a reaction tank 2A in which a plurality of particles (first particles P1 and second particles P2) are charged and a fluid F0 is introduced to form a fluidized bed. In this embodiment, the fluid F0 is a liquid.
The reaction tank 2A also has a line L1 which is an inlet pipe for introducing a fluid F0 into the reaction tank 2A, and a line L2 which is a discharge pipe for discharging the fluid F1 discharged from the reaction tank 2A to the outside of the system. Note that the arrows in Fig. 1 indicate the flow of a fluid, and in particular, the open arrows indicate the fluid flow velocity (superficial velocity).

The reaction tank 2A is a tank for carrying out a reaction by contact between a fluid F0 and particles (first particles P1 and second particles P2). As shown in FIG. 1, the fluid F0 is supplied to the reaction tank 2A through a line L1 provided at the bottom of the reaction tank 2A.
In addition, the reaction tank 2A in this embodiment is provided with partition plates 20 and 21 to form the first flow velocity region A1 and the second flow velocity region A2. The first flow velocity region A1, the second flow velocity region A2, and the partition plates 20 and 21 will be described later.

As shown in FIG. 1, when viewed from the bottom of the reaction tank 2A, the first particles P1 and the second particles P2 are layered in this order in the reaction tank 2A. After being introduced into the reaction tank 2A through a line L1, the fluid F0 passes through the first particles P1 and the second particles P2 in this order, and is discharged from the reaction tank 2A through a line L2 as a fluid F1.
In this case, it is preferable that the line L1 for introducing the fluid F0 into the reaction tank 2A is connected to a distributor (dispersion pipe, dispersion plate, etc.) provided at the bottom of the reaction tank 2A to introduce the fluid F0 into the reaction tank 2A. This makes it easy to control the fluid flow rate of the fluid F0 introduced into the reaction tank 2A.
In addition, a pump (not shown) may be provided in line L1 or line L2 so that the fluid F0 forms a stable upward flow in the reaction tank 2A.

The reaction tank 2A in this embodiment may have any structure that allows the fluid F0 and particles (first particles P1 and second particles P2) to be introduced and charged into the tank and to be retained therein.
In addition, various kinds of equipment can be provided for the reaction tank 2A in this embodiment according to the type of reaction process. For example, when anaerobic treatment is performed as the reaction in the reaction device 1A, the reaction tank 2A may be provided with an internal water temperature adjustment means, a pH adjuster feeding means, and a means for adding metals such as nitrogen, phosphorus, cobalt, and nickel, which are nutrient sources required by microorganisms. In particular, when methane fermentation is performed by acid-producing bacteria and methanogens as the anaerobic treatment, it is preferable to provide a means for recovering, purifying, and storing methane gas as equipment provided for the reaction tank 2A. In addition, it is preferable to provide a separation device for separating methane gas, treated water, and solids (such as the porous body P and aggregates of anaerobic microorganisms M described later) at the top of the reaction tank 2A.

The particles (first particles P1 and second particles P2) in this embodiment are selected according to the type of reaction process carried out in the reaction apparatus 1A (the type of fluid F0 introduced into the reaction apparatus 1A).
For example, when the reaction step is related to the production of a compound, the particles to be brought into contact with the raw material fluid F0 include metal catalysts and porous bodies that function as catalysts.
Furthermore, in the case where the reaction step involves drying or mixing of particles, the particles to be brought into contact with the fluid F0 serving as a medium include various particles to be dried or mixed.
Furthermore, when the reaction process involves a process involving adsorption or adhesion to particles, the particles to be brought into contact with the fluid F0, which is the workpiece containing the object to be treated, include porous bodies that function as adsorbents and filter materials, as well as particulate matter that contains components that react (decompose or synthesize) upon contact with the object to be treated and function as a reaction medium.

As the reaction process in the reaction apparatus 1A of this embodiment, it is possible to set a reaction process corresponding to each of the particles to be stacked.
For example, by using adsorbents with different adsorption targets as the first particles P1 and the second particles P2, it becomes possible to carry out one reaction process (adsorption process) in multiple stages in the reaction device 1A. In addition, by combining particles that undergo different reactions when contacted with the fluid F0 (for example, an adsorbent and a catalyst, an adsorbent and a particulate matter as a reaction medium, etc.) as the first particles P1 and the second particles P2, it becomes possible to combine multiple different reaction processes in the reaction device 1A.

The shape of the particles (first particles P1 and second particles P2) is not particularly limited. For example, they may be used as fine particles or as molded bodies. Examples of the shape of the molded body include a sphere, a pellet, a honeycomb, a small cylinder, a tube, a cube, a rectangular parallelepiped, and the like. In addition, the shapes of the first particles P1 and the second particles P2 may be the same or different.

In this embodiment, the first particles P1 and the second particles P2 may have different minimum fluidization velocities Umf, which are the transition points from the fixed bed to the fluidized bed. In general, the minimum fluidization velocity Umf depends on the size and specific gravity (density) of the particles. Therefore, the first particles P1 and the second particles P2 may be selected to have completely different compositions, sizes, and specific gravities, or may be selected to have the same composition but different sizes and specific gravities. More specifically, as described below, the first particles P1 may be a porous body as an adsorbent, and the second particles P2 may be a granulated product of a microorganism as a reaction medium that reacts with the target to be treated in the fluid F0. In addition, the first particles P1 and the second particles P2 may be a porous body (activated carbon, zeolite, etc.) that functions as an adsorbent, and the respective porous bodies may be combined to have different properties other than the composition (particle size, porosity, etc.) or different adsorption targets. This makes it possible to proceed with multiple or multi-stage reaction processes in one reaction tank 2A.

In particular, the first particles P1 and the second particles P2 in this embodiment are preferably different in specific gravity. At this time, the difference in specific gravity between the first particles P1 and the second particles P2 is preferably 1.2 times or more, more preferably 1.5 times or more. This allows the minimum fluidization velocity Umf of the first particles P1 and the second particles P2 to be different from each other, and by introducing the first particles P1 and the second particles P2 into the reaction tank 2, the layer of the first particles P1 and the layer of the second particles P2 naturally form a layered state in the reaction tank 2 without the need for any special operation.
In the reaction apparatus 1A in this embodiment, the following description will be based on the relationship in which the specific gravity of the second particles P2 is smaller than the specific gravity of the first particles P1.

The specific means for selecting the combination of the first particles P1 and the second particles P2 based on the specific gravity is not particularly limited. For example, when the specific gravity of each can be directly measured or calculated, the combination of the first particles P1 and the second particles P2 may be selected based on the obtained specific gravity value. In addition, when the specific gravity of each cannot be directly measured or calculated, the first particles P1 and the second particles P2 may be mixed experimentally, and a combination that separates into two layers may be selected and introduced into the reaction tank 2.

A fluid F0 is introduced through a line L1 to the first particles P1 and the second particles P2 charged into the reaction tank 2, thereby fluidizing the first particles P1 and the second particles P2 and forming a fluidized bed in the reaction tank 2.
In this case, if the fluid flow velocity (superficial velocity) in the reaction tank 2 is constant, the first particles P1 will not be fluidized if the fluid flow velocity is adjusted to match the fluidization of the second particles P2, which have a lower specific gravity and a smaller minimum fluidization velocity than the first particles P1. On the other hand, if the fluid flow velocity is adjusted to match the fluidization of the first particles P1, there is a concern that the second particles P2 will be excessively fluidized and will flow out of the tank.

The reaction apparatus 1A in this embodiment forms within the reaction tank 2 a first flow velocity region A1 through which the fluid F0 passes at a first flow velocity v1 and a second flow velocity region A2 through which the fluid F0 passes at a second flow velocity v2, and the numerical ranges of the first flow velocity v1 and the second flow velocity v2 are set based on the minimum fluidization velocity Umf1 of the first particles P1 and the minimum fluidization velocity Umf2 of the second particles P2.

The relationship between the minimum fluidization velocity Umf1 of the first particles P1 and the minimum fluidization velocity Umf2 of the second particles P2, as well as the first flow velocity v1 and the second flow velocity v2 used in the reaction apparatus 1A of this embodiment will be explained with reference to FIG. 2.

Figure 2 is a schematic diagram showing the relationship between the minimum fluidization velocities Umf1 and Umf2 of the first particles P1 and the second particles P2 used in the reaction apparatus 1A of this embodiment, and the first flow velocity v1 and the second flow velocity v2. Note that the vertical axis of Figure 2 indicates the pressure loss, and the horizontal axis indicates the flow velocity of the fluid.

Figure 2 is a schematic diagram showing the relationship between flow velocity and pressure loss when each particle (first particle P1 and second particle P2) introduced into the tank goes from a fixed bed state to forming a fluidized bed, and shows that the pressure loss increases as the flow velocity increases, and at a certain point the pressure loss becomes constant. Here, while the pressure loss is increasing, the particles are not sufficiently fluidized and remain in a fixed bed state, but when the pressure loss becomes constant, the particles are sufficiently fluidized and form a fluidized bed. The flow velocity at which the pressure loss begins to become constant differs for each particle, and this flow velocity is the minimum fluidization velocity Umf for each particle.

In the reaction apparatus 1A of this embodiment, as shown in FIG. 2, the first flow velocity v1 is greater than the minimum fluidization velocity Umf1 of the first particle P1 and the minimum fluidization velocity Umf2 of the second particle P2 (v1>Umf1, v1>Umf2), and the second flow velocity v2 is smaller than the minimum fluidization velocity Umf1 of the first particle P1 and greater than the minimum fluidization velocity Umf2 of the second particle P2 (Umf1>v2>Umf2).
As a result, the first flow rate v1 becomes a fluid flow rate capable of fluidizing the first particles P1 and the second particles P2, and the second flow rate v2 becomes a fluid flow rate capable of fluidizing only the second particles P2. Therefore, in the reaction tank 2A through which the fluid F0 passes in the order of the first particles P1 and the second particles P2, a fluidized bed in which the first particles P1 are fluidized is formed in the first flow rate region A1 through which the fluid F0 passes at the first flow rate v1, and a fluidized bed in which the second particles P2 are fluidized is formed in the second flow rate region A2 through which the fluid F0 passes at the second flow rate v2. That is, since a fluidized bed is formed for each particle (the first particles P1 and the second particles P2) in one tank, it is possible to maintain uniform and stable fluidity as a whole reaction apparatus 1A.

The minimum fluidization velocity Umf1 of the first particle P1 and the minimum fluidization velocity Umf2 of the second particle P2 can be calculated not only based on the relationship between flow velocity and pressure loss as shown in Figure 2, but also using known empirical formulas or calculation formulas based on various experiments, such as the Ergun formula and its modifications, as well as the Wen-Yu formula.

The reaction apparatus 1A in this embodiment may be any apparatus capable of forming the above-mentioned first flow rate region A1 and second flow rate region A2, and there are no particular limitations on the specific structure and means.
As an example of the formation of the first flow velocity region A1 and the second flow velocity region A2 in the reaction apparatus 1A, the structure (partition plates 20, 21) provided in the reaction tank 2 will be described below with reference to FIG.

As shown in FIG. 1, a reaction apparatus 1A in this embodiment is provided with partition plates 20 and 21 in a reaction tank 2.
The partition plate 20 has a funnel-shaped structure with a wider bottom, and is provided so as to be lower than the height of the layer formed by the first particles P1 in the reaction tank 2. As a result, a narrow channel 20a with a small cross-sectional area is formed in a part of the reaction tank 2A, as shown in Fig. 1. The fluid flow velocity passing through this narrow channel 20a is defined as a first flow velocity v1, and the region through which the fluid F0 passes at this first flow velocity v1 is defined as a first flow velocity region A1.
Here, the first flow velocity v1 is determined by the cross-sectional area of the narrow flow path 20a and the flow velocity of the fluid F0 introduced from the line L1. Therefore, the first flow velocity v1 can be controlled by designing the partition plate 20 (narrow flow path 20a) or controlling the flow velocity of the fluid F0 introduced from the line L1 so that it falls within the above-mentioned numerical range (v1>Umf1, v1>Umf2).
Furthermore, since the fluid F0 passes through the first flow velocity region A1 at a fluid flow velocity (first flow velocity v1) that is greater than the minimum fluidization velocity Umf1 of the first particle P1 and the minimum fluidization velocity Umf2 of the second particle P2, the first particle P1 fluidizes in this first flow velocity region A1 and forms a fluidized layer.
It is preferable to set the height of the partition plate 20 or the amount of the first particles P1 to be fed into the reaction tank 2A so that the height of this first flow velocity region A1 is approximately the same as the height of the layer formed by the first particles P1.

On the other hand, in the region without the partition plate 20, there is a layer formed by the second particles P2, and the fluid F0 passes through it at a second flow velocity v2 slower than the first flow velocity v1. This region is referred to as a second flow velocity region A2.
Here, the second flow rate v2 is determined by the cross-sectional area of the reaction tank 2A and the flow rate of the fluid F0 introduced from the line L1. Therefore, the second flow rate v2 can be controlled by designing the cross-sectional area (tank diameter) of the reaction tank 2A or controlling the flow rate of the fluid F0 introduced from the line L1 so that the second flow rate v2 falls within the above-mentioned numerical range (Umf1>v2>Umf2).
Furthermore, since the fluid F0 passes through the second flow velocity region A2 at a fluid flow velocity (second flow velocity v2) that is smaller than the minimum fluidization velocity Umf1 of the first particle P1 and greater than the minimum fluidization velocity Umf2 of the second particle P2, in this second flow velocity region A2, the second particle P2 fluidizes and forms a fluidized layer.

As described above, the first particles P1 and the second particles P2 are in a layered state in the reaction tank 2A, and it is preferable to maintain this layered state even when fluidized. For this reason, as shown in FIG. 1, a partition plate 21 may be provided between the first flow rate region A1 and the second flow rate region A2 in the reaction tank 2A.

As shown in Fig. 1, the partition plate 21 may be attached to the side wall of the reaction tank 2A and have a structure with an opening at the center. This prevents the first particles P1, which have risen at the first flow velocity v1 through the narrow flow channel 20a in the first flow velocity region A1, from entraining the second particles P2 when they descend along the outside of the narrow flow channel 20a (the side wall side of the reaction tank 2A), and prevents the layer formed by the first particles P1 (first flow velocity region A1) and the layer formed by the second particles P2 (second flow velocity region A2) from mixing together and disrupting the layered state.
In addition, in cases where the stacking state of the first flow velocity region A1 and the second flow velocity region A2 is unlikely to be disturbed by the upward and downward flows in the first flow velocity region A1, for example because there is a large difference in specific gravity or size between the first particle P1 and the second particle P2, the structure of the partition plate 21 may be omitted.

As described above, according to the reactor 1A of this embodiment, in a reactor that forms a fluidized bed in which two or more types of particles are fluidized, by providing multiple regions of fluid flow speed according to the properties of the particles (minimum fluidization speed), a fluidized bed can be formed for each type of particle within the reactor 1A, making it possible to maintain uniform fluidity throughout the reactor 1A. In addition, since multiple reaction processes can be carried out within a single tank, it is possible to reduce the space required for the reactor 1A and improve processing efficiency.

Hereinafter, as an example of a reaction that can be performed using the reaction apparatus 1A of this embodiment, anaerobic treatment of wastewater containing organic matter will be described.
FIG. 3 is a schematic diagram illustrating anaerobic treatment using the reaction apparatus 1A of this embodiment.
As shown in Fig. 3, the reaction tank 2A is layered with a porous body P as the first particles P1 and anaerobic microorganisms M as the second particles P2. Then, wastewater W0 containing organic matter is supplied to the reaction tank 2A as the fluid F0, and the components contained in the wastewater W0 are decomposed (anaerobic treatment) by the anaerobic microorganisms M contained inside the reaction tank 2A. Treated water W1 after anaerobic treatment is discharged from the reaction tank 2A through a line L2 provided at the top of the reaction tank 2A. At this time, it is preferable to make the reaction tank 2A a closed system and maintain an anaerobic environment.

The porous body P may be any material having a large number of pores, and examples of such materials include inorganic adsorbents such as activated carbon, zeolite, silica, diatomaceous earth, and kaolin, as well as organic adsorbents such as gel adsorbents and PVA. In particular, it is preferable to use a porous body P that has a high ability to retain anaerobic microorganisms M in addition to the ability to adsorb inhibitors that inhibit anaerobic treatment by anaerobic microorganisms M. An example of such a porous body P is activated carbon.

The anaerobic microorganisms M may be any microorganisms capable of anaerobically treating organic matter, and there are no particular limitations on the specific type of microorganism. For example, when methane fermentation is used as the anaerobic treatment, acid-producing bacteria and methanogens are used as the anaerobic microorganisms M. Other examples of the anaerobic microorganisms M include denitrifying bacteria used in denitrification treatments that reduce nitrate and nitrite, and sulfate-reducing bacteria used in sulfate reduction treatments that reduce sulfate.

As the anaerobic microorganisms M in this embodiment, isolated microorganisms may be used, or seed sludge from other reaction equipment, etc. may be used. In addition, anaerobic microorganisms M contained in wastewater W0 may be utilized.

The form of the anaerobic microorganisms M is not particularly limited, but examples include granulated microorganisms with a diameter of about 0.3 to 3 mm, known as granules. Granules are microbial masses that utilize self-immobilization, and are capable of maintaining a high concentration of bacteria. Therefore, by using granules as the anaerobic microorganisms M, a layer that maintains a high concentration of anaerobic microorganisms M is formed in the reaction tank 2A.

As described above, it is preferable to use porous bodies P and anaerobic microorganisms M in this embodiment, which have a specific gravity difference of 1.2 times or more. As a result, by introducing the porous bodies P and anaerobic microorganisms M into the reaction tank 2A, a layer of the porous bodies P and a layer of the anaerobic microorganisms M naturally form a layered state in the reaction tank 2A without the need for special operations. As shown in FIG. 3, when wastewater W0 passes through the reaction tank 2A in an upward flow, a combination is used in which the specific gravity of the anaerobic microorganisms M is smaller than the specific gravity of the porous bodies P. This makes it possible to create a layered state in the reaction tank 2A in which a layer of anaerobic microorganisms M is formed on top of the layer of porous bodies P.

In addition, a specific description will be given of a case where a methane fermentation process is performed as an example of anaerobic treatment using the reaction apparatus 1A in this embodiment.
When methane fermentation treatment is performed in the reaction tank 2A, methane fermentation proceeds through an acid production process in which the acid-producing bacteria contained in the reaction tank 2A decompose solids and polymeric organic matter such as sugars, proteins, and oils in the wastewater W0 to produce monosaccharides, amino acids, lower fatty acids, and acetic acid, and a methane production process in which the methanogenic bacteria contained in the reaction tank 2A produce methane from carbon sources such as monosaccharides, amino acids, lower fatty acids, and acetic acid in the wastewater W0.

The wastewater W0 supplied to the reaction tank 2A first comes into contact with the porous body P, which removes inhibitory substances contained in the wastewater W0 that inhibit the activity of anaerobic microorganisms M. The inhibitory substances to be removed are not particularly limited, but specific examples include sulfur, ammonia, and oils and fats (fatty acids). Depending on the components in the wastewater W0, the presence (or generation) of high concentrations of organic acids may inhibit the activity of anaerobic microorganisms M. Even in such cases, the organic acids can be adsorbed by the porous body P, reducing the concentration of organic acids in the wastewater W0, making it possible to remove inhibitory substances that inhibit the activity of anaerobic microorganisms M.

In addition, by attaching and holding anaerobic microorganisms M (particularly acid-producing bacteria) to the porous body P, the porous body P also functions as a carrier for the anaerobic microorganisms M. This causes decomposition of organic matter in the wastewater W0 around the porous body P, and the acid production process progresses. In other words, the area formed by the porous body P becomes an acid production area, and has the same function as an acid production tank in a conventional methane fermentation process.

After contacting the porous body P, the wastewater W0 then comes into contact with anaerobic microorganisms M. Here, the anaerobic microorganisms M include acid-producing bacteria and methanogens. Therefore, the acid production process and the methane production process proceed to the organic matter in the wastewater W0, and methane fermentation processing is carried out. In other words, the area formed by the anaerobic microorganisms M functions as an anaerobic treatment area.

In this way, by forming a layered state of the porous body P and the anaerobic microorganisms M in one reaction tank 2A and first bringing the wastewater W0 into contact with the porous body P, it is possible to remove inhibitors that inhibit the activity of the anaerobic microorganisms M. In addition, since the porous body P also functions as a carrier for holding the anaerobic microorganisms M, the area formed by the porous body P becomes an acid production area that holds a high concentration of acid-producing bacteria, and decomposition of organic matter in the wastewater W0 and acid production take place. The wastewater W0 that has been treated for acid production is then introduced into the anaerobic treatment area consisting of the area formed by the anaerobic microorganisms M, and methane fermentation proceeds using the products produced by the acid production treatment as a carbon source.

As described above, by using the reaction apparatus 1A and reaction method of this embodiment in the methane fermentation treatment of wastewater containing organic matter, a fluidized bed can be formed for each particle in a single-tank reaction tank containing multiple particles, uniform fluidity can be maintained, inhibitors in the methane fermentation treatment can be removed, and the carbon source supplied to the methane production process via the acid production process can be increased. This makes it possible to save space in the reaction apparatus and reaction method for performing anaerobic treatment and to improve the efficiency of the entire anaerobic treatment.
In this embodiment, methane fermentation by acid-producing bacteria and methanogenic bacteria is exemplified as the anaerobic treatment, but the present invention is not limited to this, and anaerobic treatment by other microorganisms may also be used.

As described above, in the reaction apparatus 1A of the first embodiment, a structure (partition plates 20, 21) is provided in the reaction tank as a means for forming the first flow rate region A1 and the second flow rate region A2, but the present invention is not limited to this.
Hereinafter, as other embodiments of the reaction apparatus of the present invention, examples of other aspects of the means for forming the first flow velocity region A1 and the second flow velocity region A2 will be given.

[Second embodiment]
FIG. 4 is a schematic diagram of a reaction apparatus 1B according to a second embodiment of the present invention.
As shown in FIG. 4, the reaction apparatus 1B according to this embodiment is provided with a reaction tank 2B, which has two tank diameters and forms regions with different cross-sectional areas, instead of the reaction tank 2A in the first embodiment.
Incidentally, among the configurations of the reaction apparatus 1B in this embodiment, the description of the same configurations as those of the reaction apparatus 1A in the first embodiment will be omitted.

In this embodiment, the reaction tank 2B does not form the first flow rate region A1 and the second flow rate region A2 by a narrow flow path 20a formed by a partition plate 20 provided in the reaction tank 2A, but forms the first flow rate region A1 and the second flow rate region A2 by the structure of the reaction tank 2B itself.

The reaction tank 2B in this embodiment has a structure in which the cross-sectional area S1 of the layer formed by the first particles P1 and the cross-sectional area S2 of the layer formed by the second particles P2 are different. In addition, the cross-sectional areas S1 and S2 (or tank diameters R1 and R2) are designed, or the flow rate of the fluid F0 introduced from the line L1 is controlled, so that the fluid flow rate (first flow rate v1) for the layer formed by the first particles P1 and the fluid flow rate (second flow rate v2) for the layer formed by the second particles P2 are within the above-mentioned numerical ranges (v1>Umf1, v1>Umf2, and Umf1>v2>Umf2).

As shown in FIG. 4, the reaction tank 2B may have a funnel-shaped structure with a portion of the reaction tank 2B widening upward so that the cross-sectional area S2 (or tank diameter R2) is larger than the cross-sectional area S1 (or tank diameter R1).
As a result, similar to the partition plate 20 (narrow flow path 20a) provided in the reaction tank 2A in the first embodiment, the first flow velocity v1 passing through the first flow velocity region A1 in the lower part of the reaction tank 2B becomes greater than the second flow velocity v2 passing through the second flow velocity region A2 in the upper part of the reaction tank 2B, and it becomes possible to satisfy the relationship with each minimum fluidization velocity (Umf1, Umf2).

[Third embodiment]
FIG. 5 is a schematic diagram of a reaction apparatus 1C according to a third embodiment of the present invention.
As shown in Fig. 5, the reaction apparatus 1C according to this embodiment is provided with a tank equipped with a line L3 for extracting a fluid F0 from the boundary between the layer formed by the first particles P1 and the layer formed by the second particles P2 as the reaction tank 2C instead of the reaction tank 2A in the first embodiment. In addition, the reaction apparatus 1C connects the line L3 and the line L1, and returns the extracted fluid F2 to the bottom of the reaction tank 2C via the line L1.
Incidentally, among the configurations of the reaction apparatus 1C in this embodiment, the description of the same configurations as those of the reaction apparatus 1A in the first embodiment will be omitted.

In this embodiment, the reaction tank 2C does not form the first flow rate region A1 and the second flow rate region A2 due to the structure of the reaction tank or structures provided in the reaction tank, but rather creates a first flow rate v1 and a second flow rate v2 in the reaction tank 2C by changing the inflow rate of fluid in the reaction tank 2C, thereby forming the first flow rate region A1 and the second flow rate region A2.

In the reaction tank 2C in this embodiment, a line L3 having a water intake function is provided at the boundary between the layer formed by the first particles P1 and the layer formed by the second particles P2. The line L3 and the line L1 are connected, and the fluid F2 taken up by the line L3 is introduced again into the bottom of the reaction tank 2C together with the fluid F0 via the line L1.
In addition, in this embodiment, in consideration of ease of equipment design, flow rate control, etc., it is preferable that the reaction tank 2C has a structure in which the cross-sectional area is uniform throughout the reaction tank 2C, but it may have a different cross-sectional area, like the reaction tank 2B.

In the reaction tank 2C in this embodiment, the layer formed by the first particles P1 receives the inflow amount Q1 of the fluid F0 introduced via line L1, plus the inflow amount Q2 of the fluid F2 taken via line L3. On the other hand, the layer formed by the second particles P2 receives the original inflow amount Q1 of the fluid F0. Therefore, if the cross-sectional area in the reaction tank 2C is uniform, the fluid flow rate (first flow rate v1) for the layer formed by the first particles P1 is greater than the fluid flow rate (second flow rate v2) for the layer formed by the second particles P2 by the amount of the increase in the inflow amount of the fluid into the layer formed by the first particles P1.

The inflow amount Q1 and the inflow amount Q2 are controlled so that the fluid flow rate (first flow rate v1) for the layer formed by the first particles P1 and the fluid flow rate (second flow rate v2) for the layer formed by the second particles P2 are within the above-mentioned numerical ranges (v1>Umf1, v1>Umf2, and Umf1>v2>Umf2).

As a result, the first flow velocity v1 passing through the layer formed by the first particles P1 in the lower part of the reaction tank 2C (corresponding to the first flow velocity region A1) becomes greater than the second flow velocity v2 passing through the layer formed by the second particles P2 in the upper part of the reaction tank 2C (corresponding to the second flow velocity region A2), and it becomes possible to satisfy the relationship with each minimum fluidization velocity (Umf1, Umf2).

The above-mentioned embodiment shows an example of a reaction apparatus and a reaction method. The reaction apparatus and reaction method according to the present invention are not limited to the above-mentioned embodiment, and the reaction apparatus and reaction method according to the above-mentioned embodiment may be modified within the scope of the gist described in the claims.

For example, in the reaction apparatus and reaction method of this embodiment, the first flow rate v1 and the second flow rate v2 are controlled by the structure of the reaction tank or the design of the structure provided in the reaction tank, or by controlling the flow rate of the fluid F0 introduced through the line L1, but this is not limited to the above.
For example, the first flow velocity v1 and the second flow velocity v2 can be indirectly controlled by controlling the size, specific gravity, etc. of the first particle P1 and the second particle P2 to control the values of the respective minimum fluidization velocities (Umf1 and Umf2). This makes it possible to obtain the effects of the reaction apparatus and reaction method of the present invention without significantly updating the reaction apparatus itself.

The reaction apparatus and reaction method of the present invention can be widely used for various reactions that use a fluidized bed formed by fluidizing multiple particles. In particular, the reaction apparatus and reaction method of the present invention can be suitably used for anaerobic treatment (particularly methane fermentation treatment) of wastewater containing organic matter.

1A, 1B, 1C reactor, 2A, 2B, 2C reactor, 20 partition plate, 20a narrow flow path, 21 partition plate, A1 first flow rate region, A2 second flow rate region, F0, F1, F2 fluid, L1-L3 lines, M anaerobic microorganism (granules), P porous body (activated carbon), P1 first particle, P2 second particle, Q1, Q2 inflow, R1, R2 tank diameter, S1, S2 cross-sectional area, Umf1, Umf2 minimum fluidization velocity, v1 first flow rate, v2 second flow rate, W0 wastewater, W1 treated water

Claims (4)

In a reactor in which a fluidized bed is formed by fluidizing two or more types of particles having different minimum fluidization velocities,
a first flow rate region through which a fluid passes at a first flow rate;
a second flow rate region through which the fluid passes at a second flow rate;
the first flow rate and the second flow rate are different flow rates;
the first flow rate is greater than a minimum fluidization velocity of the first particles and the second particles;
The second flow rate is less than a minimum fluidization velocity of the first particles and greater than a minimum fluidization velocity of the second particles. The reaction apparatus according to claim 1, characterized in that the difference in specific gravity between the first particles and the second particles is 1.2 times or more. 3. The reaction apparatus according to claim 1, wherein a cross-sectional area of the layer formed by the first particles is different from a cross-sectional area of the layer formed by the second particles . A reaction method using a fluidized bed in which two or more types of particles having different minimum fluidization velocities are fluidized,
The fluidized bed is
a first flow rate region through which a fluid passes at a first flow rate;
a second flow rate region through which the fluid passes at a second flow rate;
the first flow rate and the second flow rate are different flow rates;
the first flow rate is greater than a minimum fluidization velocity of the first particles and the second particles;
The method of claim 1, wherein the second flow rate is less than a minimum fluidization velocity of the first particles and greater than a minimum fluidization velocity of the second particles.