JP4370284B2 - Solar heat and biomass desalination device, and greening method using solar heat and biomass desalination device - Google Patents

Description

  The present invention relates to a solar heat and biomass-use desalination apparatus, and a greening method using solar heat and a biomass-use desalination apparatus.

  As a result of the publication of the Kyoto Protocol of the United Nations Framework Convention on Climate Change (hereinafter referred to as the Kyoto Protocol), the reduction rate of greenhouse gas emissions such as carbon dioxide and methane has reached the signatory countries such as Japan. Has been stipulated, and the goal has been required to be achieved within the commitment period.

In the Kyoto Protocol, a clean development mechanism (hereinafter referred to as CDM) is defined as a means for managing project investments in developing countries (non-Annex I countries).
In the CDM, developed countries and developing countries jointly implement a greenhouse gas reduction project in developing countries, and the developed countries receive a part of the reductions as credits (Certified Emission Reduction) and apply them to their own reductions. It is supposed to be possible.

  In addition, the Kyoto Protocol allows for the acquisition / transfer (transaction) of emissions allowances (emissions) between developed countries (hereinafter referred to as emissions trading). The credits mentioned above are included in the emissions trading that is permitted to be acquired and transferred. That is, the above-mentioned credit is used for trading in the emission trading, and revenue can be generated by this trading.

Therefore, various energy saving technologies and petroleum alternative energy technologies that can reduce emissions of carbon dioxide and the like have been proposed. Among these techniques, a technique is also included in which steam is generated using the collected solar heat to generate power or desalinate seawater (see, for example, Patent Documents 1 to 3).
JP-A-6-66453 JP-A-9-230116 JP-T-2002-517707

The above-mentioned Patent Document 1 to Patent Document 3 disclose a technique related to the shape of a solar heat reflecting section, a light collecting section, and the like in a solar heat collecting apparatus. The purpose of these disclosed techniques is to collect solar heat efficiently.
However, these solar thermal collectors collect solar heat by simply concentrating sunlight in a predetermined area, and thus have a problem that the operation time is limited to daytime. For this reason, there is a problem that the depreciation cost is higher than the case where the equipment is operated day and night due to the lowering of the equipment operation rate, and the power generation cost and the fresh water cost are higher than the use of fossil fuel. .

  Furthermore, as a result of efficiently collecting solar heat, when the temperature of the heat collecting part increases, the temperature difference between the heat collecting part and the surroundings becomes large. As a result, heat easily diffuses from the heat collecting portion to the surroundings, and conversely there is a problem that the heat collecting efficiency is lowered.

In addition, in order to operate the equipment at night, a technique using a heat storage device that stores heat during the day and releases the heat stored at night is also known. By using the heat storage device, the equipment can be operated at night to improve the equipment operating rate.
However, since the equipment cost is increased by introducing the heat storage device, there is a problem that the power generation cost and the fresh water production cost are higher than the use of fossil fuel.

Furthermore, a technique is also known in which steam is generated using heat collected by a solar heat collector, and a steam turbine is driven using this steam to generate electric power. In this technique, in order to drive a steam turbine efficiently, relatively low-temperature steam is further heated using combustion heat such as fossil fuel such as oil or gas and led to the steam turbine. By heating the steam with combustion heat such as fossil fuel in this way, the equipment can be operated even at night and high-temperature steam can be obtained. Therefore, it was possible to improve the capacity utilization rate and power generation cost.
However, when fossil fuels and the like are burned, there has been a problem that carbon dioxide and the like, which are regulated by the Kyoto Protocol, are generated.

  The present invention has been made to solve the above-described problems, and is intended to reduce the emission amount of carbon dioxide and the like to be reduced by the Kyoto Protocol, improve the equipment operation rate, and reduce the power generation cost and the fresh water cost. It is an object of the present invention to provide a solar heat and biomass desalination apparatus that can improve the temperature and a greening method using the solar heat and biomass desalination apparatus.

In order to achieve the above object, the present invention provides the following means.
A solar heat and biomass desalination apparatus according to the present invention includes a heat collecting unit that heats water by receiving solar heat, an evaporation unit that evaporates heated water, and a turbine unit that is driven by steam generated by the evaporation unit. And using the power generation unit driven by the turbine unit, burning the biomass, the combustion unit thermally connected to the evaporation unit, and at least a part of the power generated by the power generation unit, It drives the reverse osmosis membrane desalination apparatus characterized by chromatic and freshwater generator for generating fresh water from seawater, the by.

  According to the present invention, since power generation is performed using steam evaporated by solar heat, carbon dioxide discharged when supplying the same power as compared with a device that generates power using only fossil fuel, etc. Can be reduced. When this carbon dioxide reduction amount is used as a CDM, a predetermined credit is generated. The generated credit is subject to buying and selling, and the sales can reduce the cost required for power generation.

  Since the evaporation section and the combustion section are thermally connected, the steam can be heated to a higher temperature by the heat generated in the combustion section after the steam is generated while suppressing the temperature of the heat collection section. Therefore, energy loss due to heat radiation to the outside in the heat collecting part can be suppressed, and energy efficiency can be improved. Moreover, since the steam temperature supplied to the turbine can be increased, the driving efficiency of the turbine can be improved.

  By using the combustion heat generated in the combustion section, a heat source that can be used not only in the daytime but also in the nighttime can be secured. Therefore, compared with the apparatus using the solar heat which can be used only as daytime as a heat source, the equipment operation rate can be improved. As a result, the cost amortization cost can be reduced.

  Since biomass is burned in the combustion section, emissions of carbon dioxide and the like, which are subject to reduction under the Kyoto Protocol, can be reduced compared to the case of burning fossil fuels such as oil and coal. Examples of biomass include plant waste such as date palm and wheat (hereinafter referred to as date palm, etc.), and carbon dioxide generated when such biomass is burned is reduced by the Kyoto Protocol. Not included in the target carbon dioxide.

It can be obtained fresh by fresh water generator from the water such as sea water. Therefore, while generating electric power, fresh water can be supplied in a desert area etc., for example.
In addition, as a fresh water production | generation part, the thing of a reverse osmosis membrane (Reverse Osmosis: Hereafter, it describes as RO) type can be illustrated.
By constructing fresh water using electric power obtained from the combustion heat of biomass, the equipment can be operated at night compared to the method using only solar heat, and the equipment operation efficiency is improved. be able to. Moreover, compared with the method of making fresh water using a fossil fuel, the discharge | emission amount of a carbon dioxide etc. can be reduced.

In the said invention, it is desirable to have the fresh water production | generation part which produces | generates fresh water from seawater with the multistage flash system or multistage effect type desalination apparatus by using the waste heat of the steam which drive | operated the said turbine part as a heat source.
A solar heat and biomass desalination apparatus according to the present invention includes a heat collecting unit that heats water by receiving solar heat, an evaporation unit that evaporates heated water, and a turbine unit that is driven by steam generated by the evaporation unit. And a power generation unit driven by the turbine unit, a combustion unit that burns biomass and is thermally connected to the evaporation unit, and exhaust heat of steam that has driven the turbine unit as a heat source. And a fresh water generation unit for generating fresh water from seawater by a method or a multi-stage effect desalination apparatus.
According to the present invention, since fresh water is obtained from the exhaust heat of steam after driving the turbine section in the fresh water generation section, it is possible to improve fresh water formation efficiency and reduce fresh water generation costs. .
In addition, as a fresh water production | generation part, the thing of a multistage effect type | mold (Multi-Effect Distribution: Hereafter, it describes as MED) can be illustrated.

The greening method using the solar heat and biomass utilization desalination apparatus of the present invention uses fresh water produced by the solar heat and biomass utilization desalination apparatus of the present invention for growing crops, and at least a part of the crops is used as the biomass. It is made to burn by the said combustion part.

According to the present invention, fresh water can be obtained again by cultivating a crop that becomes biomass with fresh water obtained by a solar heat utilization device, and burning the crop, thereby forming a so-called closed circulation system. . Therefore, for example, even in a desert region where fresh water is insufficient, fresh water can be stably supplied, and greening can be achieved by growing crops.
The cultivation of crops as described above is included in the CDM credit generation target, and the cost required for greening can be reduced by selling the generated credit.

According to the greening method using the solar heat and biomass desalination apparatus of the present invention, since power is generated using steam evaporated by solar heat, carbon dioxide discharged when the same power is supplied is reduced. There is an effect that can be done.
Since the steam and the combustion section are thermally connected, the temperature of the steam can be further increased by the heat generated in the combustion section without reducing energy efficiency. Therefore, the driving efficiency of the turbine can be improved, and the energy efficiency in power generation can be improved. Further, by using the combustion heat in the combustion section, a heat source that can be used not only in the daytime but also in the nighttime can be secured, and the equipment operation rate can be improved.

[First Embodiment]
Hereinafter, the solar heat and biomass power generation / desalination system according to the first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic diagram illustrating the configuration of a solar thermal and biomass power generation / desalination system according to the present embodiment.
As shown in FIG. 1, a solar power and biomass power generation / desalination system (solar heat and biomass use desalination system) 1 receives a reflection part 3 that reflects sunlight and the heat of reflected sunlight, heating the supplied mineral oil or molten salt to the heat collector 5, as a heat source and heated mineral oil or molten salt by heat collector 5, a steam generator (evaporation section) 7 for evaporating water, evaporated A steam turbine (turbine unit) 9 driven by the generated steam, a generator (power generation unit) 11 driven by the steam turbine 9 to generate electric power, an RO desalination device (fresh water generation unit) 13 for producing fresh water from salt water, , An outline of a MED desalination device (fresh water generation unit) 15 that produces fresh water from the exhaust heat of steam that has driven the steam turbine 9 and a combustion furnace (combustion unit) 17 that burns biomass such as dates or wheat. It has been made.
In addition, as water supplied to the heat collection part 5 and the RO desalination apparatus 13, the water containing salt and other impurities, such as seawater and groundwater, can be mentioned, for example.

The reflection part 3 is comprised from the reflective mirror formed in the parabola shape, and is formed so that sunlight may be condensed on the focus of a parabola. A heat collecting unit 5 is disposed at the focal point of the reflecting unit 3, and the heat collecting unit 5 is held by a columnar member arranged between the reflecting unit 3.
In addition, the reflection part 3 should just be the structure which can collect solar heat by condensing sunlight, and is not specifically limited.

A supply pipe to which the mineral oil or molten salt heated from the heat collecting unit 5 is supplied is connected to the steam generator 7. Further, the steam generator 7 and a combustion furnace 17 described later are configured to be thermally connected so that the combustion heat is transmitted to the steam.
The combustion furnace 17 is a furnace for burning biomass such as date palm or wheat, and a known furnace used for this purpose can be used.
The steam turbine 9 is a turbine that is rotationally driven by being supplied with high-temperature steam generated by the steam generator 7, and a known steam turbine can be used.

The RO desalination apparatus 13 is roughly configured by a pump that boosts and supplies water using the electric power generated by the generator 11 and a reverse osmosis pressure module that generates fresh water from the pressurized water. The RO desalination apparatus 13 is a desalination apparatus using a reverse osmosis membrane, and a known reverse osmosis membrane, a pump, or the like can be used.
The RO desalination apparatus 13 is connected to a supply pipe that supplies water containing impurities such as seawater and groundwater, for example, similarly to the heat collecting unit 5. Further, a wiring for supplying electric power for driving the RO desalination apparatus 13 is arranged between the RO desalination apparatus 13 and the generator 11.

The MED desalination apparatus 15 is a desalination apparatus using a so-called steam method of a multistage effect type, and a known multistage effect type desalination apparatus can be used. Between the MED desalination apparatus 15 and the steam turbine 9, a steam pipe for supplying the steam after driving the steam turbine 9 to the MED desalination apparatus 15 is disposed.
As described above, the MED desalination apparatus 15 that is a multistage effect desalination apparatus may be disposed downstream of the steam turbine 9, or a multistage flash system desalination apparatus may be disposed. It is not what you do.

Next, the effect | action in the solar heat and biomass utilization power generation and desalination system 1 which consist of said structure is demonstrated.
As shown in FIG. 1, the sunlight incident on the reflecting mirror 3 is condensed on the heat collecting unit 5. Mineral oil or molten salt is supplied to the heat collecting unit 5 from the outside, and is heated by the heat of the collected sunlight. At this time, the temperature of the heat collecting section 5 is set to be lower than 400 ° C. The heated water is supplied to the steam generator 7, and a part of the heated mineral oil or molten salt evaporates fresh water in the steam generator 7.
On the other hand, in the combustion furnace 17, biomass such as dates is burned, and the generated combustion heat is supplied to the steam generator 7.

  In the steam generator 7, the steam absorbs the combustion heat supplied from the combustion furnace 17, is heated to a temperature of 400 ° C. or higher, and is supplied to the steam turbine 9. The steam turbine 9 is rotationally driven by the supplied high-temperature steam, and transmits the generated rotational driving force to the generator 11. The generator 11 generates power using the transmitted rotational driving force and supplies the generated power to the outside. A part of the generated power is supplied to the RO desalination apparatus 13.

The RO desalination apparatus 13 to which power is supplied boosts the pressure of water supplied from the outside and produces fresh water using a reverse osmosis membrane.
On the other hand, the steam after driving the steam turbine 9 is supplied to the MED desalination apparatus 15. The MED desalination apparatus 15 evaporates seawater with the supplied steam, and then condenses to produce fresh water.

  According to the above configuration, since power generation is performed using steam evaporated by solar heat, carbon dioxide discharged when supplying the same power as compared with a device that generates power using only fossil fuel. Etc. can be reduced. When this carbon dioxide reduction amount is used as a CDM, a predetermined credit is generated, and the sales can reduce the cost required for power generation.

  Since the steam generator 7 and the combustion furnace 17 are thermally connected, the temperature of the heat collecting section 5 is suppressed to a temperature lower than about 400 ° C., and steam is generated, and then the heat generated in the combustion furnace 17 is added. Thus, the steam can be made a steam having a temperature higher than about 400 ° C. Therefore, energy loss due to heat radiation to the outside in the heat collecting unit 5 can be suppressed, and energy efficiency can be improved. Moreover, since the steam temperature supplied to the steam turbine 9 can be increased, the driving efficiency of the turbine can be improved. Therefore, the power generation efficiency of the solar heat and biomass power generation / desalination system 1 can be improved.

  By using the combustion heat generated in the combustion furnace 17, a heat source that can be used not only in the daytime but also in the nighttime can be secured. Therefore, compared to a device that uses solar heat that can only be used during the day as a heat source, the facility operation time in a day is approximately tripled, and the facility operation rate of the solar power and biomass power generation / desalination system 1 is approximately tripled. Can be improved. Therefore, the depreciation cost of solar heat and biomass power generation / desalination system 1 can be reduced to approximately 1/3.

Since biomass such as date palm is burned in the combustion furnace 17, compared with the case where fossil fuels such as oil and coal are burned, it is possible to reduce the emission amount of carbon dioxide and the like, which is the reduction target of the Kyoto Protocol. In addition, since carbon dioxide etc. which generate | occur | produce when burning such biomass are not contained in the carbon dioxide etc. which are the reduction object of Kyoto Protocol, there exists an effect of discharge | emission amount reductions, such as a carbon dioxide.
Further, by using date palm, wheat, or the like that is often cultivated in desert areas, it is possible to more easily operate the solar power and biomass power generation / desalination system 1 in desert areas where solar heat is easily used.

By providing the solar heat and biomass power generation / desalination system 1 with the RO desalination apparatus 13 and the MED desalination apparatus 15, fresh water can be obtained from salt water containing impurities such as seawater. Therefore, while generating electric power, fresh water can be supplied in a desert area etc., for example.
By constructing fresh water using electric power obtained from the combustion heat of biomass, the equipment can be operated at night compared to the method of producing fresh water using only solar heat. Operation efficiency can be improved. Moreover, compared with the method of making fresh water using a fossil fuel, the discharge | emission amount of a carbon dioxide etc. can be reduced.

Carbon dioxide emission trading business such as solar thermal power generation, solar thermal desalination, biomass fuel, and biomass power generation can be realized at the same time.
In addition, by using CDM for these businesses, it is possible to obtain predetermined credits, and it is possible to generate income by buying and selling these credits. With this income, it is possible to reduce power generation costs or fresh water generation costs.

For example, in solar thermal power generation with a low-grade output of 10 MW, carbon dioxide emissions of 30000 t / year are reduced. If this amount of reduction is used as a CDM, it will be about 2 yen / kWh.
Thereby, the power generation cost in solar thermal power generation is equivalent to the power generation cost (5 yen / kWh) when power is generated using fossil fuel in the United States.

In this embodiment, when 24-hour operation using biomass is performed, the freshwater production cost is 50 yen / t to 100 yen / t, which is the same as the desalination cost using fossil fuel.
If CDM is used for this desalination project, revenue of about 30 yen / t is estimated, and the desalination cost can be made lower than the method using fossil fuel.

  As described above, a power generation system using solar heat and a desalination system may be combined, or only a power generation system using solar heat or only a desalination system using solar heat may be used. Even in these cases, effects such as reduction of carbon dioxide emission, improvement of facility operation efficiency, and improvement of energy efficiency can be achieved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the solar heat and biomass-based power generation / desalination system of the present embodiment is the same as that of the first embodiment. The point of doing is different. Therefore, in this embodiment, it demonstrates centering on the greening method using a solar heat and biomass utilization power generation and desalination system using FIG. 2, and description of a solar heat and biomass utilization power generation and desalination system main body etc. is abbreviate | omitted.
FIG. 2 is a diagram for explaining the outline of the greening method using the solar heat and biomass-based power generation / desalination system according to the present embodiment.
In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, and the description is abbreviate | omitted.

  The greening method using the solar heat and biomass power generation / desalination system in the present embodiment uses fresh water produced using the solar heat and biomass power generation / desalination system 1 in the date palm plantation P as shown in FIG. It is used for irrigation, and the plant waste generated in the date palm plantation P is used as biomass in the solar heat and biomass power generation / desalination system 1.

  As in the first embodiment, the solar power and biomass power generation / desalination system 1 includes a reflection unit 3 that reflects sunlight, a heat collection unit 5 that heats water by the heat of reflected sunlight, and heating. A steam generator 7 that evaporates the generated water, a steam turbine 9 that is driven by steam, a generator 11 that is driven by the steam turbine 9 to generate power, an RO desalination device 13 and a MED desalination device that produce fresh water 15 and a combustion furnace 17 for burning biomass.

  Date palm plantation P is a dry land (such as the Middle East and North Africa) where solar heat can be expected, and is generally present, and there are many plantations. A typical date palm plantation P has an area of several kilometers to several tens of kilometers.

Next, a trial calculation of a greening method using solar heat and a biomass power generation / desalination system will be described.
In general, in Date Palm Farm P, the lower branches are regularly cut and old date palm trees are cut and replanted into young trees every 15 to 20 years. Waste (biomass) is generated. For example, in the date palm farm P of 10 km square, it is estimated that about 80,000 t of biomass is generated annually.
Moreover, the amount of irrigation water required for the date palm farm P of 10 km square in the above-mentioned dry land (for example, an area where annual precipitation is about 150 mm) is about 30000 t / day.

Since the solar heat and biomass power generation / desalination system 1 uses solar heat and biomass to generate power and produce fresh water as in the first embodiment, the description thereof is omitted.
For example, when the solar heat and biomass-utilizing power generation / desalination system 1 is generated using only about 80,000 t of the biomass described above, power generation of about 10 MW is possible. When the RO desalination apparatus 13 is operated using electric power of about 10 MW, seawater of about 40000 t / day is desalinated. At this time, about 4000 t / day of fresh water is produced in the MED desalination apparatus 15 that desalinates the steam generated in the steam generator 7.
Therefore, solar heat and biomass generated from the date palm plantation P can be used to generate power of about 10 MW or more by the solar heat and biomass power generation / desalination system 1. Moreover, about 40,000 t / day or more of fresh water is produced by the solar heat and biomass power generation / desalination system 1.

  According to the greening method described above, the solar heat and biomass power generation / desalination system 1 uses the biomass discharged from the date palm plantation P only to produce fresh water, but the amount of irrigation water required in the date palm plantation P The above fresh water can be increased. That is, a closed circulation system composed of solar heat and biomass power generation / desalination system 1 and date palm plantation P can be constructed, and the greening method of this embodiment can be a sustainable greening method.

It is possible to simultaneously realize a carbon dioxide emission trading business such as solar heat and biomass power generation, or solar heat desalination and greening, biomass fuel, and biomass power generation.
In addition, by using CDM for these businesses, it is possible to obtain predetermined credits, and it is possible to generate income by buying and selling these credits. With this income, it is possible to reduce power generation costs or fresh water generation costs.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the explanation was applied to the solar heat using biomass discharged from the date palm plantation and the greening method using the biomass power generation / desalination system, but the biomass of the date palm plantation is used. The present invention is not limited to the method, and can be applied to methods using other various biomass such as biomass generated from wheat widely cultivated in Middle Eastern countries.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic explaining the structure of the solar thermal and biomass utilization power generation and desalination system which concerns on 1st Embodiment in this invention. It is a figure explaining the outline of the greening method using the solar thermal and biomass utilization power generation and desalination system which concerns on 2nd Embodiment in this invention.

Explanation of symbols

1 Solar power and biomass power generation and desalination system (solar heat and biomass desalination system)
5 Heat collection section 7 Steam generator (evaporation section)
9 Steam turbine (turbine part)
11 Generator (Power Generation Department)
13 RO desalination equipment (fresh water generator)
15 MED desalination equipment (fresh water generator)
17 Combustion furnace (combustion section)

Claims (4)

A heat collecting part for receiving water and heating water;
An evaporation section for evaporating heated water;
A turbine section driven by steam generated in the evaporation section;
A power generation unit driven by the turbine unit;
Combusting the biomass, and a combustion part thermally connected to the evaporation part,
Using at least a part of the power generated by the power generation unit, driving a reverse osmosis membrane desalination device to generate fresh water from seawater; and
Solar and biomass desalination apparatus characterized by have a. The exhaust heat of the steam drives the turbine section as a heat source, by a multistage flash method or multi-effect type desalination apparatus, solar heat according to claim 1 Symbol mounting and having a fresh water generator for generating fresh water from seawater, and Biomass desalination equipment. A heat collecting part for receiving water and heating water;
An evaporation section for evaporating heated water;
A turbine section driven by steam generated in the evaporation section;
A power generation unit driven by the turbine unit;
Combusting the biomass, and a combustion part thermally connected to the evaporation part,
Using the exhaust heat of the steam that has driven the turbine section as a heat source, a multi-stage flash system or a multi-stage effect desalination apparatus generates fresh water from seawater, and
Solar and biomass desalination apparatus characterized by have a. The fresh water generated by the solar heat and biomass desalination apparatus according to any one of claims 1 to 3 is used for growing crops, and at least a part of the crops is burned as biomass in the combustion section. A greening method using a solar water and biomass-based desalination apparatus.

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