WO2018179082A1

WO2018179082A1 - Algae concentration method and algae concentration apparatus

Info

Publication number: WO2018179082A1
Application number: PCT/JP2017/012614
Authority: WO
Inventors: 喬中山
Original assignee: 日揮株式会社
Priority date: 2017-03-28
Filing date: 2017-03-28
Publication date: 2018-10-04

Abstract

[Problem] To provide an algae concentration method and so forth that can obtain concentrated algae from a starting liquid in which algae are dispersed in water, while restraining the effects on an oil extraction process in a later stage. [Solution] To obtain concentrated algae from a starting liquid containing algae and water, in a mixing step, the starting liquid is stirred and mixed with gas and an extractant liquid that is poorly soluble in water and that can extract lipid from algal cells, to produce a mixture containing bubbles, algae, lipid, the extractant liquid, and water. In a degassing step, the gas present in the mixture is degassed. In a phase separation step, the degassed mixture is subjected to phase separation into an extraction liquid phase containing an extraction liquid into which lipid soluble in the extractant liquid has been extracted, a scum phase containing algae and lipid that is poorly soluble in the extractant liquid, and a water phase. In a scum take-off step, scum is taken off, as concentrated algae, from the scum phase.

Description

Algae concentration method and algae concentration apparatus

The present invention relates to a technique for concentrating algae in a raw material solution containing algae and water.

Some algae (microalgae) have the ability to metabolize lipids by photosynthesis, and oil produced from this type of algae is attracting attention as a “third biofuel”.

In order to industrially produce oil from algae, it is necessary to cultivate algae on a large scale, concentrate the algae in the water (raw liquid) containing the cultured algae, and then extract the oil from the algae. .
Among these treatments, the concentration of algae in the raw material liquid is difficult to implement unless a concentration method that consumes a large amount of energy, such as centrifugation, is used because the density difference between water and algae is small.

Here, Patent Document 1 discloses a method of adding a particulate thickener such as metal silicate or diatomaceous earth to a sample containing microorganisms, and forming a composition in which the microorganisms are fixed to the concentrate to concentrate the microorganisms. Are listed. In Patent Document 2, water-soluble neutral polysaccharides such as tapioca starch and glucomannan are added to suspension water containing suspensions such as blue seaweed and aquatic microalgae (phytoplankton), and the suspension is obtained. Techniques for agglomerating and removing are described.

JP 2014-204726 A Japanese Patent Laying-Open No. 2015-85219

However, in the techniques described in the cited

documents

1 and 2, a concentrated agent or a water-soluble neutral polysaccharide is mixed into the concentrated microorganism or suspension. For this reason, when these techniques are applied to the concentration of algae for oil production, these contaminants may interfere with the processing when extracting oil from the concentrated algae, or reduce the extraction efficiency. There is a risk that.

The present invention has been made under such a background, and its object is to obtain concentrated algae from a raw material liquid in which algae are dispersed in water while suppressing the influence on the subsequent oil extraction treatment. It is an object of the present invention to provide an algae concentration method and an algae concentration apparatus that can perform the above-mentioned.

The algal concentration method of the present invention is an algae concentration method for obtaining concentrated algae from a raw material solution containing algae and water.
The raw material liquid, an extractant solution that is sparingly soluble in water and capable of extracting lipids from the algae, and gas are stirred and mixed to produce bubbles, algae, lipids, an extractant solution, and A mixing step for producing a hybrid containing water;
A degassing step of degassing the gas contained in the hybrid in order to decompose the hybrid;
The degassed composite is extracted with an extract solution containing an extract obtained by extracting a lipid soluble in the extract solution, a scum phase containing the algae and a lipid poorly soluble in the extract solution, and water. A phase separation step for phase separation into phases;
And a scum extraction step of extracting, from the scum phase, scum containing the algae and poorly soluble lipid as concentrated algae.

The algae concentration method may have the following characteristics.
(A) Precipitating agglomerates from the scum phase to form a precipitated phase of aggregated algae; and aggregating algae extracting step of extracting the aggregated algae as concentrated algae from the precipitated phase. Including. Here, the precipitation step includes an operation of allowing the scum phase to stand until the precipitation phase is formed.
(B) The gas is stirred and mixed with the raw material liquid and the extractant liquid in the form of bubbles having a diameter of 1000 μm or less.
(C) The degassing step includes at least one of a depressurizing operation for depressurizing the hybrid or a defoaming operation for causing the hybrid to flow down from a perforated plate in which a plurality of holes are formed.
(D) The phase separation step includes an operation of allowing the hybrid after degassing to stand.
(E) The extraction liquid is an extraction raw material consisting of pentane, hexane, heptane, octane, nonane, decanol, dodecanol, undecanol, isopropyl ether, isobutyl ether, isoamyl ether, cyclopentane, cyclohexane, ethylcyclopentane, and methylcyclohexane. Including at least one extractant selected from the group.
(F) The gas includes at least one gas source selected from a gas source group consisting of air, nitrogen, and carbon dioxide.

Further, an algal concentration apparatus according to another invention is an algal concentration apparatus for obtaining concentrated algae from a raw material solution containing algae and water.
A raw material liquid supply line to which the raw material liquid is supplied; an extractant liquid supply line to which an extractant liquid that is sparingly soluble in water and capable of extracting lipid contained in the algae is supplied; Connected to a gas supply line to which gas is supplied, performs stirring and mixing of the raw material liquid, the extract liquid, and the gas, and generates a hybrid containing bubbles, algae, lipids, extract liquid, and water. A stirring and mixing unit;
Connected to the stirring and mixing unit via a hybrid extraction line for extracting the hybrid, and degass the gas contained in the hybrid to be extracted from the stirring and mixing unit and decompose the hybrid A degassing part;
The degassed composite is extracted with an extract solution containing an extract obtained by extracting a lipid soluble in the extract solution, a scum phase containing the algae and a lipid poorly soluble in the extract solution, and water. A phase separation part for phase separation into phases;
And a scum extraction line for extracting scum containing the algae and sparingly soluble lipids as concentrated algae from the scum phase.

The present invention performs the deaeration of the hybrid produced by stirring and mixing the raw material liquid, the extractant liquid, and the gas, whereby the hybrid is extracted with the liquid phase, the scum phase containing the concentrated algae, and the water. Since they can be separated into phases, algae concentrated with a low content of impurities can be obtained.

It is an example of the algae concentration process which concerns on embodiment of this invention. It is a block diagram of the algae concentration apparatus which concerns on embodiment. It is a vertical side view of the liquid-liquid contact tower provided in the algae concentration apparatus. It is a block diagram of the algae concentration apparatus which concerns on other embodiment. It is a vertical side view of the defoaming tower which deaerates the bubble contained in a hybrid. It is an external appearance photograph of the hybrid produced | generated by stirring and mixing a raw material liquid, an extractant liquid, and gas. It is an external appearance photograph after phase-separating the said hybrid.

<Algae concentration method>
First, an example of a processing procedure according to the algae concentration method of the present invention will be described with reference to FIG.
The raw material liquid to which the algal concentration method of this example is applied contains algae that metabolizes lipids (oil components).

In the algae concentration method of this example, a culture solution containing algae cultured in an open culture pond or a closed photoreactor may be used as a raw material solution as it is, or a part of water contained in the culture solution may be used. The culture solution after pretreatment such as preconcentration that is separated by membrane separation or the like may be used as the raw material solution.
A raw material solution obtained from a culture solution in which algae is cultured using fresh water contains algae and water. Moreover, the raw material liquid obtained from the culture solution cultured using seawater contains salt in addition to algae and water.

Algae (microalgae) contained in the raw material liquid has a size of about 1 to 100 μm and is dispersed in water. Some algae have an intracellular lipid content of about 10% to 80% by dry weight. The main oil components produced by algae include neutral lipids, phospholipids, glycolipids, etc., and some algae contain most of the oil components as hydrocarbons. Triglycerides occupying most of the neutral lipids are ester bonds of three higher fatty acid molecules and glycerol. Higher fatty acids are oleic acid (18 carbon atoms and one double bond, written as “C18: 1”. The same applies to higher fatty acids), linoleic acid (C18: 2), linolenic acid (C18: 3), palmitic acid (C16: 0), and the like. These lipids are nonpolar substances, are soluble in the later-described extractant solution, and are hardly soluble in water.
On the other hand, some lipids containing phosphorus and nitrogen exhibit poor solubility in the later-described extractant solution.

The raw material liquid containing algae and water described above is stirred and mixed together with the extractant and gas, and the process of generating a composite body containing bubbles, algae, lipids, extractant and water is performed. Performed (Process P1: Mixing step in FIG. 1).

As the extract liquid, one that is hardly soluble in water and capable of extracting lipid contained in algae is used. Extractant liquids that satisfy these requirements include linear aliphatic compounds and their isomers pentane, hexane, heptane, octane, nonane, linear higher alcohol decanol, dodecanol, undecanol, and isopropyl ether. , Isobutyl ether, isoamyl ether, naphthenic hydrocarbons cyclopentane, cyclohexane, ethylcyclopentane, and a mixture of these extractant raw materials selected from the extractant raw material group consisting of methylcyclohexane It can be illustrated.

The gas mixed with the raw material liquid and the extractant is a gas that is hardly soluble in the extractant. Examples of the gas that satisfies the requirements include a case where a gas raw material selected from a gas raw material group consisting of air, nitrogen, and carbon dioxide, or a mixture of these gas raw materials is used.

The stirring and mixing of the raw material liquid, the extractant liquid, and the gas may be performed when a multistage contact tower that counter-contacts the raw material liquid, the extractant liquid, and the gas is used (liquid contact tower 1 in FIG. 2), or A case where a line mixer provided on a pipeline through which fluid flows is used (

line mixers

51a and 51b in FIG. 4) can be exemplified. Further, if the problem of increase in stirring resistance due to the generation of the hybrid is not large, a rotary stirring blade is disposed in the stirring tank to which the raw material liquid, the extractant liquid, and the gas are supplied, and the stirring blade is You may drive and stir and mix.

During stirring and mixing, the gas may be supplied by bubbling to the raw material liquid and the extractant liquid. In addition, for example, using a known microbubble generator (bubble generating unit), bubbles (microbubbles) of 1000 μm or less, preferably in the range of several μm to several tens of μm, are used as at least one liquid of the raw material liquid or the extractant liquid. The raw material liquid and the extractant liquid may be stirred and mixed in a state where the liquid is generated and the liquid contains bubbles. Since microbubbles have a low ascending speed and can remain in the liquid for a relatively long time, they can be sufficiently brought into contact with the raw material liquid and the extractant liquid during stirring and mixing.

When the raw material liquid, the extractant liquid and the gas are stirred and mixed and brought into contact with the gas-liquid-solid (gas-water-extractant liquid-algae), the phase of the extractant liquid is shown, as shown in the experimental results described later. A sol-like hybrid containing bubbles, algae, lipids soluble in the extract liquid extracted from algae, and water is formed between the aqueous phase and the aqueous phase (FIG. 6). Even if only the gas is blown into the raw material liquid without using the extractant liquid to form microbubbles and stirring and mixing, no hybrid is formed.

The hybrid can exist stably for a relatively long period of time, and when it is left standing, it decomposes while slowly removing bubbles over a day. From this viewpoint, it is considered that the bubbles contained in the hybrid have a function of keeping the algae, the lipid, the extractant solution, and water in a hybrid state.
Moreover, when a hybrid is formed in a state containing the extract solution, lipids that are soluble in the extract solution are extracted from the algae. In addition, regarding the poorly soluble lipid contained in the algae, it is expected that the nonpolar part of the lipid molecule is drawn to the extract liquid side and exposed from the surface of the algal cells. As a result, an effect of facilitating the process of extracting oil from the concentrated algae is also expected.

In the algae concentration method of this example, in order to decompose the hybrid produced in the mixing process in a short time, a process of degassing the gas contained in the hybrid is performed (process P2 in FIG. 1: deaeration process).
As a degassing method, the inside of the container containing the hybrid may be depressurized (depressurization operation) (

depressurization tanks

2, 2a, 2b in FIGS. 2 and 4), or the hybrid is heated to grow bubbles. You may deaerate by.

As another degassing method, the hybrid may be supplied to a perforated plate in which small holes or a plurality of small holes (holes) are formed. By flowing down the hybrid through these holes, the bubbles in the hybrid are raised, and when using a porous plate, the hybrid is retained on the porous plate to combine the bubbles, or After coalescence in the hybrid, it may be repeatedly raised and separated and extinguished (defoaming tower 6 in FIG. 5, defoaming operation).

When degassing the hybrid, the algae, lipid, extractant and water cannot be maintained in an integrated state, and the hybrid is decomposed. As a result, when the degassed hybrid is allowed to stand, these substances are phase-separated based on the specific gravity difference between the substances that have formed the hybrid (Process P3 in FIG. 1: Phase separation step, FIG. 7).

In the uppermost phase after phase separation, an extract liquid phase (extract liquid phase) containing the extract liquid and lipids extracted from algae and soluble in the extract liquid is formed. A phase (scum phase) in which algae are concentrated in a scum shape is formed on the lower side of the extract. In the algae constituting the scum phase, lipids hardly soluble in the extractant remain. In addition, the scum phase may contain a part of the extractant or water that has not been phase-separated.

Furthermore, an aqueous phase is formed below the scum phase. At the bottom of the aqueous phase, a slurry-like precipitation phase is formed, in which algae in the scum phase aggregate to form aggregated algae, and then aggregated algae precipitate.

Scum is extracted as concentrated algae from the scum phase formed by the above-described phase separation (Process P4 in FIG. 1: Scum extraction step). Aggregated algae are extracted as concentrated algae from the precipitated phase (Process P4 in FIG. 1: Aggregated algae extraction step).

Here, when the degassed hybrid is decomposed, three phases of an extraction liquid phase, a scum phase, and an aqueous phase are formed in a few minutes to a few dozen minutes. Furthermore, agglomeration of algae proceeds in the scum phase, and a precipitated phase of agglomerated algae is formed in about several tens of minutes to 1 hour. Therefore, the extraction of aggregated algae from the precipitated phase may be omitted by executing the extraction of the scum at the stage where the scum phase is formed without waiting for the formation of the precipitated phase.

Concentrated algae (scum, agglomerated algae) obtained in these steps are subjected to oil extraction treatment, and lipids remaining in the algae are extracted as oil components.
Further, the extract is extracted from the extract liquid phase, and after the extract liquid and the lipid are separated by evaporation or the like, the lipid separated from the extract liquid is used as an oil component.

<Algae concentrator>
Next, a configuration example of an algae concentration apparatus that performs the algae concentration method described above will be described with reference to FIGS.
2 and 3 show an embodiment of an algae concentrator that performs stirring and mixing of raw material liquid, extractant liquid, and gas using a multistage contact tower (liquid contact tower 1) provided in the stirring and mixing section. ing.

As shown in FIG. 2, the lower part of the liquid-liquid contact tower 1 is supplied with a light extractant that is a light liquid via an extractant supply line 102, and the upper part is overlapped with a raw material liquid supply line 101. A raw material liquid which is a liquid is supplied.
In addition, on the front side of the supply position of the extractant liquid to the liquid-liquid contact tower 1, bubbles are generated that generate microbubbles in the extractant liquid using the gas (nitrogen in this example) supplied from the gas supply line 103. A portion 11 is provided, and the extractant liquid is supplied to the liquid-liquid contact tower 1 in a state containing nitrogen. As the bubble generation unit 11, a known configuration such as a gas-liquid swirl flow method or an ejector method can be used.

Nitrogen that did not contribute to the formation of the hybrid is extracted from the top of the liquid-liquid contact tower 1. In addition, an extractant liquid phase containing a large amount of extractant liquid that has not contributed to the formation of the hybrid object is formed on the upper phase side of the hybrid material, and the tower is connected to the extractant liquid phase via the circulation supply line 104. After the top liquid (extractant liquid) is extracted, it is supplied again to the lower part of the liquid-liquid contact tower 1 and the intermediate height position (intermediate position). The tower top liquid resupplied to the lower part joins the above-described extractant liquid supply line 102, and a newly supplied mixture of the extractant liquid and the tower top liquid is supplied at the bubble generation unit 11. In the state containing nitrogen, it is supplied to the liquid-liquid contact tower 1.

Air bubbles forming microbubbles in the top liquid using nitrogen supplied from the gas supply line 103 also on the front side of the supply position of the top liquid re-supplied to the intermediate position of the liquid-liquid contact tower 1 A generator 11 is provided, and the top liquid is re-supplied to the liquid-liquid contact tower 1 in a state containing nitrogen.

As a specific configuration example of the liquid-liquid contact tower 1, for example, a case where WINTRAY (registered trademark), for which the applicant has a patent, is used (Japanese Patent No. 5410044, US Pat. No. 8,240,640, etc.).
As shown in FIG. 3, in the liquid-liquid contact tower 1, a large number of trays 121 are arranged along the height direction of the tower body 120 at intervals. When these trays 121 are viewed from the upper surface side, each tray 121 is disposed so that one end thereof overlaps with another tray 121 adjacent in the vertical direction. Each tray 121 is provided with a vertical wall 122 for storing a liquid on the dispersed phase side (in the example shown in FIG. 3, an extractant liquid containing nitrogen: a light liquid) below the tray 121. Furthermore, each vertical wall 122 is provided with an opening 123 for discharging the dispersed phase laterally in a plurality of stages along the height direction of the vertical wall 122.

With the above-described configuration, the extractant liquid containing nitrogen supplied to the lower part and the intermediate position of the liquid-liquid contact tower 1 (including the tower top liquid circulated and supplied) is united by collecting on the lower side of the tray 121. And the dispersion caused by being discharged from the opening 123 of the vertical wall 122, the liquid-liquid contact tower 1 is raised.

At this time, the extractant liquid is discharged in the horizontal direction (horizontal direction) through the opening 123, so that the liquid on the continuous phase side that descends in the liquid-liquid contact tower 1 (in the example shown in FIG. 3, the raw material liquid: Intersect with heavy fluid). At this time, stirring and mixing accompanied by gas-liquid-solid (gas-water-extractant solution-algae) contact of the raw material solution containing algae and water, the extractant solution, and nitrogen proceeds (mixing step).

In the multistage liquid-liquid contact tower 1, the above-mentioned gas-liquid-solid contact is repeatedly performed at the extractant liquid discharge position from the opening 123 provided in each vertical wall 122, whereby the raw material liquid and The extractant solution and nitrogen are sufficiently stirred and mixed.

At the bottom of the liquid-liquid contact tower 1, the raw material liquid (water that is a residual liquid) after the algae is harvested flows down to the hybrid side, and is discharged to the outside such as a wastewater treatment facility via the residual liquid extraction line 106. It is extracted.
On the other hand, on the top side of the liquid contact tower 1, there is provided a settler region (not shown) in which the tray 121 and the vertical wall 122 are not disposed. In this region, the liquid mixture and the liquid contact tower together with the hybrid are provided. The phase is separated into an extract liquid phase and an aqueous phase composed of an extract liquid and water that have not risen to the formation of the hybrid but rise in the interior. The extract liquid on the extract liquid phase side is extracted from the liquid contact tower 1 via the circulation supply line 104 and re-supplied to the liquid contact tower 1. Moreover, the water in the water phase flows down again in the liquid-liquid contact tower 1 together with the raw material liquid as a heavy liquid.

Thus, the raw material liquid and the extractant liquid containing nitrogen are supplied so as to balance the amount of water extracted from the bottom of the liquid-liquid contact tower 1, and the top liquid extracted from the tower top side is supplied. When circulating, hybrids accumulate in the settler area.
Therefore, at the timing when a certain amount of the hybrid is accumulated, the on-off valve V1 provided in the hybrid extraction line 105 is opened, and the hybrid is extracted toward the decompression tank 2. In addition, you may provide the mesh etc. for suppressing that a hybrid is extracted to the circulation supply line 104 side with a tower top liquid in the upper part side of a settler area | region.

In addition, as shown in the experimental results in the examples described later, in the liquid-liquid contact tower 1, it is not an essential requirement that the extractant liquid containing nitrogen be a dispersed phase and the raw material liquid be a continuous phase. The extract liquid containing gas) may be the continuous phase and the raw material liquid may be the dispersed phase. In this case, the liquid-liquid contact tower 1 shown in FIG. 3 is turned upside down so that the raw material liquid, which is a heavy liquid, is collected on the tray 121 and then discharged from the opening 123 of the vertical wall 122. To do.

In this case, since the hybrid tends to be formed on the downstream side of the continuous phase side, the settler region is provided on the bottom side of the liquid-liquid contact tower 1 to perform phase separation between the hybrid and the aqueous phase. Thereafter, the accumulated hybrid is intermittently extracted toward the decompression tank 2 via the hybrid extraction line 105 connected to the bottom side of the liquid-liquid contact tower 1.

The decompression tank 2 shown in FIG. 2 constitutes the deaeration unit of the present embodiment, and accommodates the hybrid body extracted from the liquid-liquid contact tower 1 via the hybrid body extraction line 105. Moreover, the decompression tank 2 plays the role which deaerates the gas contained in a hybrid by decompressing internal atmosphere in the state which accommodated the hybrid (deaeration process).

An evacuation line 201 for evacuating the decompression tank 2 is connected to the upper surface of the decompression tank 2, and an unillustrated vacuum evacuation unit such as a vacuum pump is provided on the downstream side of the vacuum exhaust line 201. Yes. Further, a pressure adjusting line 202 for supplying a pressure adjusting gas (nitrogen in this example) is connected to the upper surface of the pressure reducing tank 2 in order to return the pressure in the pressure reducing tank 2 in a reduced pressure state to normal pressure. ing.
The bottom of the decompression tank 2 has a cone shape, and a decomposition / hybrid extraction line 203 for extracting the degassed hybrid is connected to the lower end of the cone.

After accommodating the hybrid extracted from the liquid-liquid contact tower 1 in the decompression tank 2, the on-off valves V1 and V3 provided in the hybrid extract line 105, the pressure control line 202, and the decomposition hybrid extract line 203, respectively. , V2 is closed, and the on-off valve V4 provided in the vacuum exhaust line 201 is opened. As a result, the vacuum tank 2 is evacuated, and the vacuum tank 2 containing the hybrid becomes a reduced pressure atmosphere within a range of about 0.4 to 0.9 atm. Bubbles) are degassed.
As described above, the gas contained in the hybrid has a role of keeping the algae, lipid, extractant solution, and water in a hybrid state, so that the hybrid starts to decompose with degassing.

When the vacuum in the decompression tank 2 is exhausted until the gas contained in the hybrid is sufficiently degassed, the on-off valve V4 of the vacuum exhaust line 201 is closed and the on-off valve V3 of the pressure control line 202 is opened. Nitrogen is introduced into the decompression tank 2, and the atmosphere in the decompression tank 2 is returned to normal pressure.
Thereafter, the on-off valve V2 of the decomposition / hybrid extraction line 203 is opened, and the degassed hybrid is extracted into the stationary separation tank 3. When the extraction of the hybrid is completed, the on-off valve V2 is closed so that the next hybrid can be received from the liquid-liquid contact tower 1.

The degassed hybrid is allowed to stand, for example, for several tens of minutes to one hour in the static separation tank 3, and the phase separation into the extraction liquid phase, the scum phase, the aqueous phase, and the precipitation phase proceeds. (Phase separation step). From the uppermost extraction liquid phase, the extraction liquid is extracted through the extraction liquid extraction line 302, and from the scum phase, scum, which is an algae concentrated through the scum extraction line 301, is extracted. (Algae extraction process).

In this example, the lower phase aqueous phase and the precipitated phase of the stationary separation tank 3 are extracted to the separation tank 4 via the lower phase extraction line 303, and the aqueous phase and the precipitated phase are separated in the separation tank 4. Re-separate. Thereafter, the aggregated algae that are concentrated algae are extracted from the precipitated phase via the aggregated algae extraction line 402 (aggregated algae extraction step). Further, water on the water phase side is extracted to the outside such as a wastewater treatment facility via a supernatant water extraction line 401.
The stationary separation tank 3 and the separation tank 4 described above constitute the phase separation unit of this example. In addition, it is not essential to provide the separation tank 4 after the stationary separation tank 3, and the extract, scum, water, and concentrated algae may be directly extracted from the stationary separation tank 3. Moreover, the pressure-reduction tank 2 which deaerates a hybrid body may be combined with the separation tank 4, and a phase-separation process may be implemented in the pressure-reduction tank 2 after deaeration is performed.

Furthermore, a plurality of decompression tanks 2, stationary separation tanks 3, and separation tanks 4 may be provided. In this case, even in a period in which operations such as deaeration and phase separation are performed in one tank 2 to 4 on the rear stage side, the other tanks 2 to 4 in which these operations are not performed. From the liquid-liquid contact tower 1, the decompression tank 2, and the stationary separation tank 3 on the front stage side, a hybrid or the like can be extracted.

Next, a configuration example of an algae concentration apparatus in which

line mixers

51a and 51b are provided in the stirring and mixing unit will be described with reference to FIG.
In the algae concentrator shown in FIG. 4, devices having the same functions as those of the algae concentrator described with reference to FIGS. 2 and 3 are denoted by the same reference numerals as those used in FIGS. In addition, when a plurality of (for example, two) devices having the same function are provided, an identification code “a, b” is added at the end of each code.

The algae concentrator shown in FIG. 4 includes, as an agitation and mixing unit,

line mixers

51a and 51b that agitate and mix the raw material liquid, the extractant liquid, and gas (nitrogen in this example), and the coarse fluid after the agitation and mixing

Settlers

52a and 52b that perform separation are provided. Furthermore, the algae concentrating apparatus of this example has a configuration in which a pair of a line mixer 51a-settler 52a-decompression tank 2a on the front stage side and a group of line mixer 51b-settler 52b-decompression tank 2b on the rear stage side are connected in series It has become.

The

line mixers

51a and 51b have a known configuration in which movable or fixed agitating blades are arranged in the pipelines, and agitation and mixing of the fluid flowing through the pipelines proceeds. In this example, after nitrogen is previously supplied to the extractant using the

bubble generating parts

11a and 11b, the raw material solution, the extractant solution, and nitrogen are stirred and mixed in the

line mixers

51a and 51b. .

The

settlers

52a and 52b are configured as receiving tanks that receive the fluid after being agitated and mixed by the

line mixers

51a and 51b. The fluid after the agitating and mixing is a column top liquid containing a large amount of the extractant liquid component therein. The crude product is roughly separated into a hybrid and a bottom liquid containing a lot of water.

Each of the

settlers

52a and 52b circulates and supplies the column top liquid to the

line mixers

51a and 51b via the

circulation supply lines

104a and 104b, and a part of the column bottom liquid also passes through the column bottom liquid circulation supply lines 107a and 107b. Then, it is circulated and supplied to the

line mixers

51a and 51b.

On the other hand, the remaining column bottom liquid that is not circulated in the front-stage settling 52a is supplied to the rear-stage line mixer 51b via the column bottom liquid transfer line 108. Further, in the latter-stage settler 52b, the remaining column bottom liquid that is not circulated is extracted as a residual liquid after the algae is harvested through a residual liquid extraction line 106 to a wastewater treatment facility or the like. It is.

The operation of the algae concentrating apparatus having the above-described configuration will be described. The extractor liquid supplied from the extractant supply line 102a and the extractor circulated through the circulation supply line 104a are supplied to the upstream line mixer 51a. The liquid at the top of the settler 52a containing a large amount of chemical liquid components is supplied in a state in which nitrogen is included in the bubble generation unit 11a.

Further, the raw material liquid supplied from the raw material liquid supply line 101a and the tower bottom liquid containing a large amount of water circulated and supplied via the tower bottom liquid circulation supply line 107a are supplied to the line mixer 51a. Then, stirring and mixing of the raw material liquid, the extractant liquid, and nitrogen is performed (mixing step).

The stirred and mixed fluid is roughly separated into a hybrid and a column top liquid and a column bottom liquid that did not contribute to the generation of the hybrid in the settler 52a, and the accumulated hybrid is intermittently supplied to the decompression tank 2a. It is pulled out towards.
Since the contents of the deaeration process in the decompression tank 2a, the stationary separation tank 3, the phase separation process in the separation tank 4, the scum extraction process, and the aggregated algae extraction process are the same as those described using FIG. The description of is omitted.

Here, as compared with the multistage liquid-liquid contact tower 1 described with reference to FIGS. 1 and 2, the ability to advance the stirring and mixing of the raw material liquid, the extractant liquid, and nitrogen only with the line mixer 51a on the front stage side. May be low and the amount of hybrid produced may be small (algal concentration is not sufficient).
Therefore, the algae concentrator of this example supplies the remaining tower bottom liquid that is not circulated and supplied as the raw material liquid of the downstream line mixer 51b via the tower bottom liquid transfer line 108, and again with the extractant liquid containing nitrogen and Are mixed to produce a hybrid from the algae remaining in the tower bottom liquid.

The action of the settler 52b is the same as the settler 52a on the front stage, except that the remaining tower bottom liquid that is not circulated is discharged to the outside as the residual liquid after harvesting the algae. Further, the contents of the deaeration process in the decompression tank 2b, the stationary separation tank 3, the phase separation process in the separation tank 4, the scum extraction process, and the aggregated algae extraction process are the same as those described with reference to FIG. is there.

FIG. 4 shows an example in which the stirring and mixing units (line mixer 51a-settler 52a, line mixer 51b-settler 52b) including the

line mixers

51a and 51b are connected in series. Accordingly, three or more stirring and mixing sections may be connected in series. On the other hand, if the algae can be sufficiently concentrated using only one stage of the line mixer 51a, it is not essential to provide a plurality of stirring and mixing sections.

The algal concentration technique according to the embodiment described above has the following effects. By degassing the hybrid produced by stirring and mixing the raw material liquid, the extractant liquid and the gas, the hybrid is extracted with the liquid phase, the scum phase containing concentrated algae, the aqueous phase, and the algae. Since it can be separated into an agglomerated phase, it is possible to obtain an algae that is concentrated in a state of low impurity content.

Next, FIG. 5 carries out the deaeration (deaeration process) of the hybrid using the defoaming tower 6 which is a deaeration part instead of the

decompression tanks

2, 2 a and 2 b described with reference to FIGS. An example is shown.
The defoaming tower 6 includes perforated plates 61 arranged in multiple stages, and a hybrid is dispersedly supplied from a dispersion nozzle 64 provided above the uppermost perforated plate 61. The mixture dispersedly supplied into the defoaming tower 6 is blocked by the wear 63 and accumulated on the porous plate 61, and then flows down through a plurality of small holes (holes) 610 provided in the porous plate 61. In doing so, deaeration by the mechanism described above proceeds. Then, the mixture passes through the multi-stage perforated plate 61 and the deaeration is repeated, whereby the hybrid is decomposed. On the other hand, the gas separated from the hybrid is guided by the upcomer 62 and rises in the defoaming tower 6. Further, the inside of the defoaming tower 6 shown in FIG.

Moreover, although the above-mentioned embodiment demonstrated the application example of the technique which concentrates the algae which produces an oil component (lipid), the application range of the said technique is not limited to this example. For example, it may be applied to the concentration of algae producing pigments such as β-carotene (C ₄₀ H ₅₆ ) and astaxanthin (C ₄₀ H ₅₂ O ₄ ), which are other useful components other than lipids, You may apply to concentration of microorganisms other than the algae which produce a useful component. When applied to these microbial concentration methods and microbial concentration apparatuses, an extract solution that is poorly soluble in water and capable of extracting other useful components from algae and microorganisms is selected.

(Experiment 1)
Formation of a hybrid was confirmed by stirring and mixing the raw material liquid, the extractant liquid, and the gas under various conditions.
[Example 1-1]
Separation funnel (1 L) of seawater from Oarai Coast, Ibaraki Prefecture, and 200 mL of marine algae aqueous solution that is 10 times concentrated raw material and 200 mL of N-hexane (hereinafter referred to as “hexane”) as extractant ), Shaken at 250 spm (Strokes per minute) for 30 minutes using a shaker, and allowed to stand. As a result, a third phase was formed between the hexane phase and the aqueous phase. The third phase was a hybrid containing bubbles (atmosphere in the separatory funnel), algae, lipids, hexane and water.
[Example 1-2]
200 mL of a freshwater algae aqueous solution, which is a 10-fold concentrated raw material sample, and 200 mL of hexane, which is an extractant, are collected from a pond in the Oarai Laboratory site of Oarai Research Institute in Oarai, Ibaraki Prefecture, and shaken. The mixture was shaken at 250 spm for 30 minutes using a vessel and allowed to stand. As a result, a third phase was formed between the hexane phase and the aqueous phase. The third phase was a hybrid containing bubbles (atmosphere in the separatory funnel), algae, lipids, hexane and water.
From Examples 1-1 and 1-2, for both marine algae and freshwater algae, a mixed solution was obtained by stirring and mixing a raw material solution containing algae and water, an extractant solution, and a gas. It was confirmed that it was possible to generate.

[Example 2-1]
After collecting 200 mL of a freshwater algae aqueous solution, which is a 10-fold concentrated raw material solution, and 200 mL of hexane, which is an extractant, from a pond in the Oarai Laboratory site of JGC Corporation, put it into a separatory funnel. Nitrogen gas was introduced to expel the air and fill with nitrogen gas. Thereafter, the separatory funnel was shaken at 250 spm for 30 minutes using a shaker and allowed to stand. As a result, a third phase was formed between the hexane phase and the aqueous phase. The third phase was a hybrid containing bubbles (nitrogen in the separatory funnel), algae, lipids, hexane and water.
[Example 2-2]
The experiment was performed under the same conditions as in Example 2-1, except that the gas introduced into the separatory funnel was changed to carbon dioxide gas. As a result, a third phase was formed between the hexane phase and the aqueous phase. The third phase was a hybrid containing bubbles (carbon dioxide in the separatory funnel), algae, lipids, hexane and water.
Even if the gas mixed with the raw material liquid and the extractant solution is changed from air (Example 1-2) to nitrogen (Example 2-1) and carbon dioxide (Example 2-2), a hybrid is produced. I was able to confirm.

[Example 3-1]
200 mL of a fresh aqueous algae aqueous solution, which is a 10-fold concentrated raw material sample, and 200 mL of decanol, which is an extractant, are collected from a pond in the Oarai Laboratory site of JGC Corporation, and 250 spm using a shaker. Shake for 30 minutes and let stand. As a result, a third phase was formed between the decanol phase and the aqueous phase. The third phase was a hybrid containing bubbles (atmosphere in the separatory funnel), algae, lipids, decanol and water.
[Example 3-2]
The experiment was performed under the same conditions as in Example 3-1, except that the extractant was changed to diisopropyl ether. As a result, a third phase was formed between the diisopropyl ether phase and the aqueous phase. The third phase was a hybrid containing bubbles (atmosphere in the separatory funnel), algae, lipids, diisopropyl ether and water.
It was confirmed that a hybrid was formed even when the extractant solution was changed from hexane (Example 1-2) to decanol (Example 3-1) or diisopropyl ether (Example 3-2).

[Example 4-1]
100 mL of a freshwater algae aqueous solution, which is a 10-fold concentrated raw material sample, and 300 mL of hexane, which is an extractant, are collected from a pond in the Oarai Laboratory site of JGC Corporation and placed in a separatory funnel and 250 spm using a shaker Shake for 30 minutes and let stand. As a result, a third phase was formed between the hexane phase and the aqueous phase. The third phase was a hybrid containing bubbles (atmosphere in the separatory funnel), algae, lipids, hexane and water.
[Example 4-2]
The experiment was performed under the same conditions as in Example 4-1, except that 300 mL of the raw material liquid placed in the separating funnel and 100 mL of the extractant were used. As a result, a third phase was formed between the hexane phase and the aqueous phase. The third phase was a hybrid containing bubbles (carbon dioxide in the separatory funnel), algae, lipids, hexane and water.
Even if the volume ratio of the raw material liquid to the extractant is changed to 1/3 (Example 4-1), 1/1 (Example 1-2), 3/1 (Example 4-2), the hybrid Was confirmed to be generated.

(Experiment 2)
Using the multistage liquid-liquid contact tower 1, a hybrid formation experiment was conducted.
[Example 5]
A. Experimental conditions
50 L of a fresh aqueous algae aqueous solution, which is a raw material solution collected from JGC Corporation's Oarai Laboratory site and concentrated 10 times, was charged into a raw material tank, and 50 L of hexane as an extractant solution was charged into the extractant tank. The raw material liquid is supplied from the raw material tank to the upper part of the liquid-liquid contact tower 1 at 100 L / h, and the extractant liquid is 100 L / h, nitrogen gas in the bubble generation unit 11 (product number BL12AA-12-D4, manufactured by Nitta Corporation). Was supplied to the lower portion of the liquid-liquid contact tower 1. The liquid-liquid contact tower 1 has 18 stages of WINTRAY provided with the tray 121 and the vertical wall 122 described with reference to FIG. 3 inside the tower main body 120 having a width of 100 mm × depth of 40 mm × contact area height of 2,000 mm. It has become the composition. In addition, a settler region in which WINRAY is not disposed is provided above and below the contact region. Similar to the example shown in FIG. 3, an extractant liquid containing nitrogen was selected as a dispersed phase, and a raw material liquid was used as a continuous phase.
The bottom liquid (water) that flowed out from the bottom of the liquid-liquid contact tower 1 was returned to the raw material tank and recycled. Moreover, the tower top liquid (extractant liquid) which flowed out from the top of the liquid-liquid contact tower 1 was returned to the extractant tank and recycled. The operation of the liquid-liquid contact tower 1 was carried out for 2 hours, and the produced hybrid was intermittently extracted from the nozzle installed in the settler region.
B. Experimental result
As a result of the experiment, a hybrid was accumulated between the hexane phase and the aqueous phase in the settler region at the top of the liquid-liquid contact tower 1.
The algae concentration (based on dry weight) of the raw material liquid in the raw material tank at the start of the experiment is 0.05 g / L, and the algae concentration in the raw material tank after the passage of 1 hour and 2 hours is 0.021 g / L, 0.0. It was 0145 g / L. It was confirmed that 71% of algae were removed from the raw material liquid by the stirring and mixing treatment for 2 hours using the liquid-liquid contact tower 1, and harvested as a hybrid.

[Example 6]
A. Experimental conditions
The experiment was performed under the same conditions as in Example 5 except that the liquid-liquid contact tower 1 shown in FIG. 3 was turned upside down, the extractant liquid containing nitrogen was selected as the continuous phase, and the raw material liquid was the dispersed phase. . Furthermore, the harvested hybrid was degassed and phase-separated into a hexane phase (extraction liquid phase), a scum phase, an aqueous phase, and a precipitation phase, and then scum and aggregated algae were extracted.
B. Experimental result
As a result of the experiment, a hybrid was accumulated between the hexane phase and the aqueous phase in the lower settler region of the liquid-liquid contact tower 1.
The algal concentration of the raw material liquid in the raw material tank at the start of the experiment was 0.081 g / L, 1 hour, 2 hours, and the algal concentrations in the raw material tank were 0.051 g / L and 0.045 g / L. It was. After 2 hours, it was confirmed that 44% of the algae were removed from the algae aqueous solution.
When the results of Examples 5 and 6 were compared, it was confirmed that the harvest efficiency of algae was higher when the extract liquid containing nitrogen was selected as the dispersed phase.
In Example 6, the volumes of scum and aggregated algae extracted after phase separation were 14.8 mL and 4.7 mL, respectively, and the total of both (hereinafter also referred to as “concentrate”) was 19.5 mL. Met. 44% of the algae in 50 L of the raw material liquid is concentrated to 19.5 mL of concentrated liquid. In other words, since 19.5 mL of the concentrated liquid algae was dispersed in 50 L of the raw material liquid, it can be said that the concentrated liquid is the result of concentration of about 2500 times.

[Example 7]
A. Experimental conditions
The experiment was performed under the same conditions as in Example 5 except that the extraction liquid and nitrogen were separately supplied from the bottom of the tower instead of the method of previously mixing nitrogen into the extraction liquid using the bubble generation unit 11. It was. Nitrogen gas was supplied in the form of bubbles having an average diameter of several millimeters using a sintered metal nozzle.
B. Experimental result
As a result of the experiment, a hybrid was accumulated between the hexane phase and the aqueous phase in the settler region at the top of the liquid-liquid contact tower 1.
The algal concentration of the aqueous algae solution in the raw material tank at the start of the experiment was 0.094 g / L, and the algal concentration in the raw material tank after 2 hours was 0.0545 g / L. After 2 hours, 42% of the algae were removed from the aqueous algae solution.
When the results of Examples 5 and 7 were compared, it was confirmed that the yield of algae was higher when the gas was supplied in a state where the bubble diameter was small.

[Example 8-1]
The state after 1 hour had passed since the hybrid obtained in the liquid-liquid contact tower 1 was transferred to the eggplant-shaped flask (1 L) was observed (FIG. 6). An extract liquid phase containing a lot of hexane that did not contribute to the formation of a hybrid was formed in the upper phase, and a hybrid phase was formed as an intermediate phase, and an aqueous phase containing a large amount of water that did not contribute to the formation of a hybrid was formed in the lower phase. The crude separation state was achieved.
[Example 8-2]
The state after 18 hours had passed after extracting the hybrid was observed (FIG. 7). It can be confirmed that the hybrid is decomposed as the bubbles are removed and phase-separated into a hexane phase (extraction liquid phase), a scum crude, a water phase, and a precipitated phase of aggregated algae.
Furthermore, as a result of analysis of the hexane phase, the presence of C16 to C18 fatty acids, triglycerides and the like was confirmed. On the other hand, the component containing nitrogen (N) and phosphorus (P) was not confirmed. This can be said to be a result of extraction of non-polar lipids soluble in hexane.

DESCRIPTION OF SYMBOLS 1 Liquid contact tower 101 Raw material liquid supply line 102 Extractant liquid supply line 103 Gas supply line 105 Hybrid

body extraction line

2, 2a, 2b
Depressurization tank 3 Static separation tank 4

Separation tank

51a, 51b

Line mixer

52a, 52b
Settler

Claims

In the algae concentration method for obtaining a concentrated algae from a raw material solution containing algae and water,
The raw material liquid, an extractant solution that is sparingly soluble in water and capable of extracting lipids from the algae, and gas are stirred and mixed to produce bubbles, algae, lipids, an extractant solution, and A mixing step for producing a hybrid containing water;
A degassing step of degassing the gas contained in the hybrid in order to decompose the hybrid;
The degassed composite is extracted with an extract solution containing an extract obtained by extracting a lipid soluble in the extract solution, a scum phase containing the algae and a lipid poorly soluble in the extract solution, and water. A phase separation step for phase separation into phases;
And a scum extraction step of extracting, from the scum phase, scum containing the algae and a sparingly soluble lipid as the concentrated algae.
A precipitation step of precipitating agglomerated algae from the scum phase to form a precipitated phase of agglomerated algae;
The algae concentration method according to claim 1, further comprising: an aggregate algae extraction step of extracting the aggregate algae as the concentrated algae from the precipitation phase.
2. The algal concentration method according to claim 1, wherein the gas is stirred and mixed with the raw material liquid and the extractant liquid in the form of bubbles having a diameter of 1000 μm or less.
The degassing step includes at least one of a depressurizing operation for depressurizing the hybrid and a defoaming operation for causing the hybrid to flow down from a perforated plate in which a plurality of holes are formed. The algae concentration method as described.
The algae concentration method according to claim 1, wherein the phase separation step includes an operation of allowing the hybrid after deaeration to stand.
The algae concentration method according to claim 2, wherein the precipitation step includes an operation of allowing the scum phase to stand until the precipitation phase is formed.
The extractant solution is selected from the extractant group consisting of pentane, hexane, heptane, octane, nonane, decanol, dodecanol, undecanol, isopropyl ether, isobutyl ether, isoamyl ether, cyclopentane, cyclohexane, ethylcyclopentane, and methylcyclohexane. The algae concentration method according to claim 1, further comprising at least one extractant raw material.
2. The algal concentration method according to claim 1, wherein the gas includes at least one gas source selected from a gas source group consisting of air, nitrogen, and carbon dioxide.
In the algae concentration device for obtaining the algae concentrated from the raw material liquid containing algae and water,
A raw material liquid supply line to which the raw material liquid is supplied; an extractant liquid supply line to which an extractant liquid that is sparingly soluble in water and capable of extracting lipid contained in the algae is supplied; Connected to a gas supply line to which gas is supplied, performs stirring and mixing of the raw material liquid, the extract liquid, and the gas, and generates a hybrid containing bubbles, algae, lipids, extract liquid, and water. A stirring and mixing unit;
Connected to the stirring and mixing unit via a hybrid extraction line for extracting the hybrid, and degass the gas contained in the hybrid to be extracted from the stirring and mixing unit and decompose the hybrid A degassing part;
The degassed composite is extracted with an extract solution containing an extract obtained by extracting a lipid soluble in the extract solution, a scum phase containing the algae and a lipid poorly soluble in the extract solution, and water. A phase separation part for phase separation into phases;
An algae concentration apparatus comprising: a scum extraction line for extracting scum containing the algae and poorly soluble lipids as concentrated algae from the scum phase.
The phase separation unit includes a flocculated algae extraction line for extracting the flocculated algae as concentrated algae from the precipitated phase of the flocculated algae formed by sedimenting the agglomerated algae from the scum phase. The algae concentrator according to claim 9, characterized in that
The stirring and mixing unit includes a multistage contact tower for performing the stirring and mixing by bringing the raw material liquid that is a heavy liquid, the extractant liquid that is a light liquid, and a gas into countercurrent contact. The algae concentrator according to claim 9.
12. A circulation supply line for supplying a tower top liquid that flows out from a tower top side of the contact tower and contains a large amount of the extractant liquid as a light liquid to the contact tower is provided. Algae concentration equipment.
The said circulation supply line merges with the said extract liquid supply line, The liquid mixture of the said extract liquid and a tower top liquid is supplied to the said contact tower as a light liquid, It is characterized by the above-mentioned. Algae concentrator.
The stirring and mixing unit includes a line mixer that stirs and mixes the raw material liquid, the extractant liquid, and a gas, and a tower top liquid that contains a lot of components of the extractant liquid after being stirred and mixed by the line mixer. The algae concentrating device according to claim 9, further comprising: a mixed body and a settler that roughly separates into a column bottom liquid containing a large amount of water.
The gas supply line merges with at least one of the raw material liquid supply line or the extractant liquid supply line, and the raw material liquid supply line or the extractant liquid supply line to which the gas supply line merges uses the gas. A bubble generating unit for generating bubbles having a diameter of 1000 μm or less is provided in the liquid of the raw material liquid or the extractant liquid, and the liquid is supplied to the stirring and mixing unit in a state including the bubbles. The algae concentration apparatus according to claim 9.
The deaeration unit accommodates the hybrid body extracted via the hybrid body extraction line, and serves as a vacuum exhaust line for degassing the gas contained in the hybrid body by reducing the internal atmosphere. The algae concentrator according to claim 9, comprising a connected decompression tank.
The deaeration part includes a plurality of perforated plates in which a plurality of hole portions are formed, and the composite body extracted through the composite body extraction line is caused to flow down from the perforated plate, thereby the composite body. The algae concentration apparatus according to claim 9, further comprising a defoaming tower for degassing the gas contained in the algae.
The phase separation unit is connected to the scum extraction line, and includes a stationary separation tank for allowing the hybrid after being deaerated at the deaeration unit to stand still and to advance the phase separation. The algae concentrating device according to claim 9.
The extract liquid supplied from the extract liquid supply line is pentane, hexane, heptane, octane, nonane, decanol, dodecanol, undecanol, isopropyl ether, isobutyl ether, isoamyl ether, cyclopentane, cyclohexane, ethylcyclopentane, methyl. The algae concentrator according to claim 9, comprising at least one extractant selected from the extractant group consisting of cyclohexane.
The algae concentrator according to claim 9, wherein the gas supplied from the gas supply line includes at least one gas source selected from a gas source group consisting of air, nitrogen, and carbon dioxide.