JP5595172B2 - Concentration difference power generator - Google Patents

Description

  The present invention relates to a concentration difference power generation apparatus that generates power using two solutions having different concentrations, and more particularly to an open cycle concentration difference power generation apparatus.

In recent years, a concentration difference power generation apparatus has been proposed that uses two solutions having different concentrations, such as seawater and river water, and generates power using the osmotic pressure between the two liquids separated by a semipermeable membrane.
The osmotic pressure is a pressure acting from a solvent or a low concentration solution toward a high concentration solution. That is, a solution of a solute that does not pass through the semipermeable membrane is directed from a relatively low concentration solution to a relatively high concentration solution through the semipermeable membrane when separated by the semipermeable membrane at different concentrations. Since a solvent flow occurs, the solvent flow that occurs through the semipermeable membrane is called osmosis, and the pressure is called osmotic pressure. In addition, the semipermeable membrane mentioned above is a membrane which permeate | transmits only a solvent.

As such a concentration difference power generation device, two types of an open cycle and a closed cycle are known.
In one open cycle, two solutions having different concentrations are supplied to a permeation apparatus separated by a semipermeable membrane, and electric power is generated using the permeation and osmotic pressure of the solvent passing through the semipermeable membrane. The solution after passing through the permeation device and the solvent after power generation are both treated as waste water. That is, in the case of an open cycle using seawater and river water, for example, seawater and fresh water introduced from the sea or river are returned to the sea or river as drainage after being used for concentration difference power generation.

  However, in the closed cycle, for example, by combining a concentration cycle such as a multiple effect method (MED) used for seawater desalination, the solution that has passed through the permeation device is concentrated to produce a solvent and a concentrated solution. Since the solvent and the concentrated liquid thus generated are returned to the permeation device and used for the concentration difference power generation, the concentration difference power generation is continued by circulating in the same closed loop system.

  As a technology related to the above-described concentration difference power generation device, a semipermeable membrane (see Patent Document 1) composed of a thin film layer (diffusion layer) of a non-porous material and one or more layers (porous layer) of a porous material, Known is an osmotic heat engine that converts osmotic pressure into electric power using a semipermeable membrane (see Patent Document 2), and a driving method of a prime mover using osmotic energy related to concentration difference power generation in a closed cycle (see Patent Document 3). It has been.

Special table 2004-50564 gazette Special table 2010-509540 Special table 2007-533884 gazette

By the way, the open cycle concentration difference power generation apparatus uses fresh water such as river water and seawater as a general working fluid.
However, the concentration of seawater is about 3.5 wt%, and therefore it is difficult to obtain high osmotic pressure between river water / seawater. From such a background, in an open cycle concentration difference power generation apparatus, it is desired to improve power generation efficiency by obtaining a larger osmotic pressure between two solutions having a difference in concentration.
The present invention has been made to solve the above-described problems, and the object of the present invention is to provide an open system capable of achieving an improvement in power generation efficiency by obtaining a larger osmotic pressure between two solutions having different concentrations. The object is to provide a cycle concentration difference power generation device.

In order to solve the above problems, the present invention employs the following means.
The concentration difference power generation device according to the present invention is a concentration difference power generation device that uses two solutions having different concentrations and generates electric power by converting the osmotic pressure of a solvent flowing through the semipermeable membrane in the permeation device into mechanical energy. The osmotic pressure generating part of the osmotic device is placed vertically so that the flow direction of the solution is in the vertical direction, and the osmotic pressure generating part of the osmotic device is kept warm and / or heated. is there.

  According to such a concentration difference power generation device, since the osmotic pressure generating portion of the osmotic device is kept warm and / or heated, the characteristic that the osmotic pressure varies depending on the temperature of the solution is utilized, and the solution flowing through the osmotic pressure generating portion is High osmotic pressure can be obtained by raising the temperature.

And since the osmotic pressure generating part of the osmotic device is placed vertically so that the flow direction of the solution is in the vertical direction, concentration polarization formed around the semipermeable membrane can be prevented or suppressed. .
In the case where the osmotic pressure generating portion is placed vertically, concentration polarization can be prevented or suppressed by natural convection by heating the solution and raising the temperature.

  In the above invention, the permeation apparatus preferably includes an ultrasonic wave generating means for minutely vibrating the solution on the high concentration side, whereby concentration polarization can be prevented or suppressed.

According to the present invention described above, in an open cycle concentration difference power generation device, it becomes possible to obtain a larger osmotic pressure between two solutions having a difference in concentration, and therefore, a mechanical force obtained by converting the osmotic pressure. Energy can be increased to generate more power.
That is, since the osmotic pressure obtained between fresh water (river water, etc.) and seawater can be increased, an open-cycle concentration difference power generation device that uses fresh water and seawater to generate power is significantly improved in power generation efficiency. An effect is obtained.

It is a figure which shows the semipermeable membrane module structural example of an osmosis | permeation apparatus as a reference example of the density | concentration difference power generation apparatus which concerns on this invention, (a) is principal part cross-sectional front view of the semipermeable membrane module provided with the osmotic pressure generation | occurrence | production part, (b) ) Is an enlarged view of a cross section showing a heat insulating wall surface portion of (a). 1 is a cross-sectional front view of an essential part showing an installation example in which a semipermeable membrane module provided with an osmotic pressure generating unit is vertically installed in the permeation device shown in FIG. 1 as an embodiment of a concentration difference power generation device according to the present invention . . It is a systematic diagram of a device configuration showing a direct connection type concentration difference power generation device as a configuration example of a concentration difference power generation device of an open cycle according to the present invention. It is a systematic diagram of a device configuration showing a tank switching type concentration difference power generation device as a configuration example of an open cycle concentration difference power generation device according to the present invention.

Hereinafter, an embodiment of a concentration difference power generator according to the present invention will be described with reference to the drawings. In the embodiment described below, the two solutions having different concentrations also include a pure solvent having a concentration of 0% in which the low concentration solution does not contain any solute.
The concentration difference power generation device 1 shown in FIG. 3 is a direct connection type, and includes a permeation device 10, a low concentration solution system 20 that supplies fresh water as a low concentration solution to the permeation device 10, and a high concentration for the permeation device 10. A high-concentration solution system 30 that supplies seawater as the concentration solution and a turbine 3 that drives the generator 2 are configured.

The low-concentration solution system 20 supplies river water to the infiltration device 10 and drains river water that has passed through the infiltration device 10. This low-concentration solution system 20 includes a river water supply source 21, a fresh water pump 23 driven by, for example, an electric motor 22, and a fresh water flow path 24 through which river water flows.
The river water supply source 21 includes one that directly supplies river water from the river and one that supplies river water once stored in the river water storage tank, and any of them may be adopted.

The high concentration solution system 30 supplies seawater to the permeation device 10 and drains the seawater that has passed through the permeation device 10. The high-concentration solution system 30 includes a seawater supply source 31, a seawater pump 32, and a seawater flow path 33 through which seawater flows. In the illustrated configuration example, the shaft output of the turbine 3 that drives the generator 2 described above is used as a drive source of the seawater pump 32, but the configuration is not limited thereto.
The seawater supply source 31 includes one that supplies seawater directly from the sea and one that supplies seawater once stored in a seawater storage tank, and any of them may be adopted.

  A concentration difference power generation apparatus 1A called a tank switching type shown in FIG. 4 includes an infiltration device 10, a low concentration solution system 20 that supplies river water to the infiltration device 10, and a high concentration solution system 40 that supplies seawater to the infiltration device 10. And a turbine 3 for driving the generator 2. That is, the tank switching type concentration difference power generation apparatus 1A is substantially the same as the direct connection type concentration difference power generation apparatus 1 except for the configuration of the high concentration solution system 40 for supplying seawater. . Therefore, about the other structure, the same code | symbol as the direct connection type mentioned above is attached | subjected, and detailed description is abbreviate | omitted.

The high concentration solution system 40 supplies seawater to the infiltration device 10 and drains the seawater that has passed through the infiltration device 10.
The high-concentration solution system 40 is provided with two seawater tanks 41a and 41b filled with seawater. In this method, for example, a filling pump 43 driven by an electric motor 42 is driven, and two seawater tanks 41 a and 41 b are preliminarily filled from a seawater supply source 44.

  When operating the concentration difference power generation apparatus 1A, for example, seawater is introduced from one of the seawater tanks 41a and 41b by a seawater pump 46 driven by an electric motor 45. 10 is supplied. In such a switching type, when either one of the seawater tanks 41a and 41b becomes empty, the other tank is switched to the other and the supply of seawater is continued, and the empty tank is refilled with seawater.

The direct connection type and tank switching type concentration difference power generation apparatuses 1 and 1A are each provided with the permeation apparatus 10 having the same configuration. The permeation device 10 is separated into a semipermeable membrane 11 which is an osmotic pressure generating portion, and a flow path for flowing low-concentration solution river water and high-concentration solution seawater is formed inside the vessel 12. In this case, the river water (solvent) on the low concentration solution side permeates the semipermeable membrane 11 and flows into the sea water on the high concentration solution side.
In a normal infiltration device 10, for example, as in the reference example shown in FIG. 1, a vessel 12 is placed horizontally, and a low-concentration solution and a high-concentration solution inlet / outlet are provided at both left and right ends in the axial direction.

The permeation device 10 of FIG. 1 is a semipermeable membrane module provided with a number of hollow fiber-like semipermeable membranes 11 horizontally disposed inside a substantially cylindrical vessel 12.
A seawater inlet 13a and a river water outlet 14b are provided at the left end of the vessel 12 on the paper surface, and a seawater outlet 13b and a river water inlet 14a are provided at the right end of the paper surface. In this case, river water flows through the hollow fiber-shaped semipermeable membrane 11, and seawater flows outside the semipermeable membrane 11.
In addition, the code | symbol 17 in a figure is the heat insulation wall surface part comprised so that the osmotic pressure generation | occurrence | production part in the vessel 12 might be heat-retained and / or heated.

Accordingly, one seawater flows into the infiltration device 10 from the seawater inlet 13a on the left side of the paper, and flows out from the seawater outlet 13b on the right side of the paper together with the permeated water that has permeated from the river water. Further, the other river water flows into the infiltration device 10 from the river water inlet 14a on the right side of the paper, and the flow rate of the river water that has permeated into the seawater decreases and flows out of the river water outlet 14b on the left side of the paper.
That is, when seawater and river water pass through the permeation device 10, the concentration decreases on the seawater side due to the addition of permeated river water, and the flow rate of the permeated water decreases and flows out on the river water side.

As a result, the seawater supplied to the osmosis device 10 is supplied to the turbine 3 by obtaining an osmotic pressure and increasing the flow rate by merging with the river water that has permeated from the river water side. That is, the main energy of the fluid supplied to the turbine 3 is due to the osmotic pressure, and this energy is converted into mechanical energy of shaft output by driving the turbine 3. It is converted into electric power by the driven generator 2.
The seawater that has driven the turbine in this manner is drained to the ocean or the like in a state where the concentration is reduced by the merge of river water. In addition, the river water which flowed out from the river water outlet 14b of the infiltration device 10 is drained into a river or the like.

In the present embodiment, the semipermeable membrane 11 of the osmotic pressure generating unit is stored in order to increase the temperature of seawater and river water flowing through the osmotic device 10 of the concentration difference power generation device 1, 1 </ b> A described above to obtain a high osmotic pressure. The installed vessel 12 is heated and kept warm.
This utilizes the characteristic that a larger osmotic pressure can be obtained as the temperature of the solution supplied to the permeation device 10 is higher. For example, as shown in FIG. 1B, a wall surface member 12a constituting the vessel 12 is used. A heat insulating wall 15 is formed by covering the outer periphery of the heat insulating material 15 with the heat insulating material 15 and keeping the heat, and installing a heater 16 inside the heat insulating material 15 to heat it.

That is, in order to increase the temperature of river water and seawater flowing through the permeation device 10, the permeation device 10 includes a heat retaining material 15 as a heat retaining means and a heater 16 as a heating means. In addition, such a heat insulating material 15 and the heater 16 may have a structure in which only one of them is provided.
When a high osmotic pressure is obtained in this way, the power generation amount obtained by driving the turbine 3 and the generator 2 increases, so that the power generation efficiency of the concentration difference power generators 1 and 1A is improved.
Further, in order to increase the osmotic pressure, the temperature of the solution flowing through the above-described permeation apparatus 10 only needs to be high. Therefore, not only the configuration in which the permeation apparatus 10 is directly heated and kept warm, but also, for example, A heating means such as a heater or use of exhaust heat may be provided at an appropriate position of the system 30 to raise the solution temperature, and the infiltration device 10 may be simply kept warm.

In the semipermeable membrane module of the osmosis device 10 described above, concentration polarization that hinders osmotic pressure occurs around the semipermeable membrane 11 in the horizontal direction. Since this concentration polarization is a concentration difference that occurs in the vicinity of the high concentration solution side of the semipermeable membrane 11, for example, as shown in FIG. 2, the permeation device is such that the flow direction of river water and seawater is vertical. If ten semipermeable membrane modules are used in a vertical position, concentration polarization can be prevented or suppressed by the action of gravity.
In order to prevent or suppress such concentration polarization, the semipermeable membrane module may be placed vertically, and the temperature of the semipermeable membrane module may be increased by heating the solution described above. In this case, natural convection generated in the solution in the semipermeable membrane module may be used. Prevents or suppresses concentration polarization.

Furthermore, in order to prevent or suppress the above-described concentration polarization, it is also effective to provide the penetrating device 10 with ultrasonic wave generation means (not shown) that microvibrates seawater, which is a high-concentration solution. This ultrasonic wave generating means is an ultrasonic wave generating device installed at an appropriate position of a high concentration solution system 30 for supplying a high concentration solution to the permeation device 10, and the high concentration solution is vibrated with ultrasonic waves to prevent concentration polarization. Or it can be suppressed.
When concentration polarization is prevented or suppressed in this way, a high osmotic pressure can be obtained in the osmosis device 10, so that the amount of power generated by driving the turbine 3 and the generator 2 increases, and the concentration difference power generation devices 1, 1A. The power generation efficiency is improved.

As described above, according to the above-described embodiment, since a larger osmotic pressure can be obtained between two solutions having different concentrations such as fresh water / seawater, mechanical energy obtained by converting the osmotic pressure. Can be increased to generate more power. That is, since the osmotic pressure obtained in the permeation device is increased, the power generation efficiency is improved in the open-cycle concentration difference power generation device that generates power using fresh water and seawater.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary, it can change suitably.

DESCRIPTION OF SYMBOLS 1,1A Concentration difference power generator 2 Generator 3 Turbine 10, 10A Infiltration device 11 Semipermeable membrane 12 Vessel 12a Wall member 15 Heat insulating material 16 Heater 17 Heat insulating wall surface portion 20 Low concentration solution system 30, 40 High concentration solution system

Claims (2)

In a concentration difference power generation device that uses two solutions with different concentrations and converts the osmotic pressure of the solvent flowing through the semipermeable membrane in the permeation device into mechanical energy to generate electricity,
The osmotic pressure generating part of the osmotic device is placed vertically so that the flow direction of the solution is up and down,
A concentration difference power generation device characterized in that the osmotic pressure generating part of the permeation device is kept warm and / or heated. The concentration difference power generation device according to claim 1, wherein the permeation device includes ultrasonic generation means that minutely vibrates the solution on the high concentration side.

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