DE102009015925A1 - Photobioreactor to cultivate and reproduce phototrophic organisms in liquid phase by reacting with gaseous, solid and/or liquid additive during illumination with sun- and/or artificial light, comprises controlling device and solar elements - Google Patents

Abstract

The photobioreactor for the cultivation and reproduction of phototrophic organisms in liquid phase by reacting with gaseous, solid and/or liquid additives during illumination with sun- and/or artificial light for the extraction of biomass (5) and/or its metabolic products and the utilization of surplus light energy, comprises a device for controlling light transparency and heat input, and semi-transparent thin-film solar elements (1), which are opaque or light-impermeable and are transparent for photosynthetic-active radiation, where the energy-rich radiation coverts into electrical energy. The photobioreactor for the cultivation and reproduction of phototrophic organisms in liquid phase by reacting with gaseous, solid and/or liquid additives during the illumination with sun light and/or artificial light for the extraction of biomass (5) and/or its metabolic products and the utilization of surplus light energy, comprises a device for controlling light transparency and heat input, and semi-transparent thin-film solar elements (1), which are opaque or light-impermeable and are transparent for the photosynthetic-active radiation, where the energy-rich radiation coverts into electrical energy. The phototrophic organisms are microorganisms, algae, cyanobacteria or higher plant cells. The solar elements is provided on a base material with a screened coating and freely remaining zones, where only parts of the reactor wall are provided with opaque or light-impermeable solar elements and the freely remaining parts serve as window for the incidence of light. The light intensity acting on the reactor is controllably reduced by a specific nano-structured coating (2) of the reactor, which uses an electrochromic effect to color itself by applying an electric voltage and to influence the light transmission and the heat input, where the coating acts as a shading element. The entire reactor wall, the surfaces exposed to the light incidence or the parts of the reactor are provided with semi-transparent solar elements. The semi-transparent solar elements are geometrically structurally rigid or adapted as films flexible to the surface of the photobioreactor, and form an outer wall (3) of the bioreactor, are directly mounted on the outer side of the bioreactor or are introduced to the light-permeable bioreactor surface with an air gap, where the electrical energy produced by the semitransparent solar elements or solar cells is used for adjusting the determined operational parameter such as for controlling the light permeability, tempering the reactor contents or feeding into external network.

Description

The The invention relates to new photobioreactors for cultivation and propagation of phototrophic organisms and / or formation of their Metabolites in the liquid phase with the help of additional solid, liquid and / or gaseous Substances exposed to sunlight and / or artificial light Light. Phototrophic organisms can be microorganisms, algae, Cyanobacteria or higher plant cells.

Known Photobioreactors affect both closed systems of different Geometry, u. a. tubular or so-called "flat-panel" reactors, as well as open systems (eg "open pond" basins / ponds).

The Closed systems tend to be more environmentally sensitive completed (with the exception of the necessary and discharges of media, light, biomass, etc.). you Advantage is a contamination-free and reproducible operation the plants. The corresponding photobioreactors must both the mass transfer processes from the gaseous and the liquid phase into the particulate phase the living cells as well as the light energy transport through the Bioreactor wall and allow the fluid flow.

Known Photobioreactors use the so-called "flashing light effect", by increasing the turbulence in the liquid Phase is achieved and causes the organisms only for a short time (about 1 Hz) of the prevailing at the reactor outer surface exposed to high inhibiting light intensity. The is sufficient for a high photosynthesis activity, since the recorded light energy in the subsequent dark phases can be implemented, but does not damage the cells.

In systems with a horizontal tubular structure, the turbulence is generated by a corresponding liquid flow. In the case of vertical cylindrical or flat Air-Lift bioreactors (eg flat-panel), the turbulence is generated by ascending reaction gas, usually CO ₂ -containing gas. To achieve the required turbulence, however, a high equipment and energy costs for the liquid pump or the gas compressors is required (about 400 to 2000 W per m ³ reactor contents).

all previously used photobioreactors, regardless of whether one horizontal tubular system or a vertical air-lift principle is used in common is that the light energy input optimized shall be. That is, it must be too high a light energy input be avoided, since the light energy primarily in for the phototrophic organisms harmful thermal energy is converted.

For the phototrophic organisms used for biomass and material production in technological processes, the inhibiting light intensity is about 2,000 μmol / m ² s, the optimum range is about 200 to 400 μmol / m ² s and at a light intensity less than 25 μmol / m ² s limits the photosynthesis.

At But many sites on earth are responsible for photosynthesis effective solar radiation higher than that of the cells required for the production of biomass or their metabolites Light intensity.

So z. For example, the photobioreactors for the microalgae Chlorella sp. with a light intensity of 180 μmol / m ² s and the cyanobacteria Spirulina sp. operated with a light intensity of 50 .mu.mol / m ² s. But even in Germany, daylight reaches a light intensity of approx. 2000 μmol / m ² s under direct irradiation.

This There is a problem of photoinhibition in previous photobioreactors z. In algae, if they light over a long period of time are exposed. In order to stabilize the photosynthesis, they are after the prior art either the organisms by circulation shadowed in the depth of the suspension or the reactor is controlled by mechanical Elements darkened at times.

In WO1997 / 011154 describes a photobioreactor for the cultivation of algae biomass with CO ₂ gases in which the shading of a stationary thin algal layer (0.1-5 mm), which is located on nonwoven webs, achieved by their rotation in a frame with a solid cover and clear windows becomes. Due to the high mechanical complexity for permanent rotation of the entire reactor, only small volume applications are possible here.

The equipped with high turbulence according to the prior art tubular or "flat-panel" photobioreactors can z. B. for microalgae only with mechanical insensitive species are operated because of the turbulence Shearing forces that damage the microalgae.

In WO2000 / 061719 a photobioreactor is specified, which has an improved light input due to surface enlargement. The light distribution is here achieved by a strong turbulence, whereby the algae are brought to the light. This is reinforced by a surface-enlarging geometry of the reactor space, in particular by glass extensions, which are located on the reactor chamber inner wall. The duration of the lighting phases should be controlled by the frequency of light contact, that is, by the shearing forces generating turbulence accordingly. The energy density in the reactor space should continue to be increased by the use of so-called wavelength shifter. By the wavelength shifter, a light portion of the radiation is shifted into the frequency band which is absorbable by the phototrophic microorganisms used. In this case, the wavelength shift is to be effected by fluorescent substances which, after absorption of light, emit light in another wavelength range. For this purpose, it is provided that the fluorescent substances are present in a carrier material, which is connected as a layer with the reactor surface or the organism suspension is added.

In WO2008 / 079724 a coating of the photobioreactor is carried out with a dye which prevents the transmission of a portion of the visible ultraviolet or infrared light, so as not to block photosynthesis. However, these wavelength shifters realize only a fixed frequency shift and are not controllable.

Of the The invention was therefore based on the problem of a photobioreactor to create, in which the light entry so limited and / or regulated can be that the phototopic organisms in the reactor no light and / or temperature inhibition but are sufficient Photons for the growth of organisms and / or theirs Metabolites can accumulate, and at the same time the excess light energy electrical energy is won.

This Problem is solved according to claim 1 thereby that the new photobioreactors for cultivation and propagation of phototrophic organisms in the liquid phase by reaction with gaseous, solid and / or liquid additives at Exposure to sunlight and / or artificial light Extraction of biomass and / or its metabolites and to use excess light energy with a Device for controlling the light transmission and so that the heat input and semi-transparent solar panels to Conversion of excess light energy into electrical Energy are provided.

Phototrophic organisms may be microorganisms, algae, cyanobacteria or higher plant cells. As an essential gaseous component is used in particular CO ₂ . This new photobioreactor can be designed both as a horizontal tubularer as well as a vertical air-lift bioreactor, condition is a translucent outer reactor wall. Several reactor modules with semitransparent solar elements can be connected in series hydraulically, pneumatically and electrically.

When Semitransparent solar elements are preferably semitransparent Thin-film solar elements suitable, in particular those the transparent for the photosynthetically active radiation while absorbing the high-energy radiation of light and convert it into electrical energy.

Suitable but are also opaque or opaque solar elements with a screened coating and remaining zones the base material or if only parts of the reactor wall with opaque or opaque solar elements are provided and the remaining parts as windows for the entrance of light serve.

to Control of light transmission and thus of heat input and the wavelength range serves, for example, a nanostructured electrochromic coating of the reactor to which a electrical voltage is applied. About a central Control, z. B. via a bus system, there is a regulated Shading of the reactor. 3 volts are enough for that.

Preferably This coating is called nanostructured electrochromic film sandwiched with the thin film solar element and / or connected to the photobioreactor. This can be the for a optimal growth of the organisms required light intensity specifically regulate and / or modulate the incoming light.

The Shading allows the turbulence of the suspension and the so reducing shear force input into the fluid, as damage to the organisms by excessive light is avoided can be. At a light transmission between 15 and 50% can at high daytime temperatures the surface temperature of the Reactor to be kept below 30 degrees Celsius.

Of the new photobioreactor allows a significant improvement the growth of the organisms under different environmental conditions, in each case the optimal light intensity for the organisms used can be targeted. At the same time, there is considerable room for maneuver given for the optimization of the system.

The for other applications, adverse light transmission of thin-film solar elements is in the inventive Reactor used to damage the organism cells too high a light energy input with simultaneous energy production to prevent.

The generated by the semitransparent solar elements of excess light energy electrical energy can be used to operate or to set certain operating parameters, eg. B. for Control of the light transmission or for temperature control of the photobioreactor can be used. In addition, excess electrical energy can also be fed into external grids.

The Semitransparent solar elements can have different embodiments exhibit. According to their nature, z. B. as glass, can they approximated the geometric shape of the reactor or z. B. flexible as films of the surface of the reactor be adjusted.

she can be on the entire reactor wall, parts of it or mounted on the exposed to the light surfaces be. In doing so, they can themselves the outer Form reactor wall or outside directly on the reactor wall or with an air gap to the outer reactor wall to be appropriate.

For their use in photobioreactors is the more appropriate the lower they are the total energy transmittance and thus the harmful Heat load in the reactor and the higher the light transmission (Transmission), so that enough light energy for the biomass growth is present in the reactor.

Of the Cooling costs can be further reduced if the solar elements constructive with an air gap to the surface of the reactor are attached. This is the heat converted portion of the light emitted to the outside again and does not contribute to the heating of the reactor interior at.

By semitransparent solar elements can be a phototrophic organisms inhibiting light intensity of about 2,000 .mu.mol / m ² s in the optimum range of 200 to 400 .mu.mol / m ² s transform.

there the property of the semitransparent solar elements is used, that they allow only about 15% of the solar energy through, but the transmission relatively regularly over the entire visible light spectrum takes place, so that by them alone no wavelength shifts occur. For the production of solar power from sunlight By contrast, the solar elements still use about 75% of the sunlight.

• – Amorphe Silizium Solarzellen (aSi) auf Glassubstraten oder Folien

Suitable semitransparent solar elements are preferably those with a transparency in the visible range of preferably 10% -30%. As solid or flexible semitransparent solar cells with different structure, for example:

• - Amorphous silicon solar cells (aSi) on glass substrates or foils

• – CIS-Dünnschicht-Solarzellen und Module

The aSi modules are laminated as solid thin-film solar cells glass-glass laminates or flexibly as PVB film. The aSi coating is opaque or a very thin solar cell layer with a semi-transparent effect. As opaque amorphous solar cells, those are used in which a part of the coating is removed by stripping or laser scanning in the laser process, so that a light transmission of about 10% is formed.

• - CIS thin-film solar cells and modules

• – Cadmium-Tellurid-Dünnschicht-Zellen auf Glassubstrat

The CIS solar modules (copper indium selenide) can achieve efficiencies of 11% to 13%. Their semitransparency is achieved by a screening in the variants dot, line and diamond solution. With these thin-film solar cells, a transparency of up to 50% can be achieved.

• - Cadmium telluride thin-film cells on glass substrate

The Cadmium telluride thin-film cells achieve efficiency of about 7%. The advantage of CdTe cells is lower Temperature sensitivity as well as in a high sensitivity to diffused solar radiation. The fine thin structuring lines for the individual cells of glass-glass standard modules let light through so that they have a semitransparency in backlight exhibit.

EXAMPLES

The Invention will be described below with reference to 4 embodiments be explained.

1 (Flat panel) shows a schematic representation of a photobioreactor for the production of phototrophic organisms with a nanostructured electrochromic coating and integrated solar cell

2 (Air-Lift) shows a schematic representation of a photobioreactor with a nanostructured electrochromic coating and integrated solar cell

3 (Bubble column) shows a schematic representation of an air-lift photobioreactor with a nanostructured electrochromic coating and integrated solar cell

Embodiment 1

According to 1 form the semitransparent thin-film solar cells 1 the bioreactor wall 3 , The nanostructured electrochromic layer 2 is between the semitransparent solar elements 1 and the wall of the reactor 3 applied. The bioreactor wall faces the main light entrance directly. The semitransparent solar elements are either incorporated as a glass-glass laminate in the reactor module or as a flexible film on the translucent ge reactor outer wall applied. With a low turbulent flow, the organisms, especially microalgae, placed in the optimal light zone. The flow of the medium 4 with the biomass 5 can through the liquid supply 6 and the ascending CO ₂ -containing gas supply 7 be generated. The medium is performed for the purpose of degassing, the temperature and the harvest in an external cycle, not shown.

Not illustrated sensors for monitoring the process parameters, such as pH, temperature, electrical power of photovoltaic cells, complete the system.

Example 2

According to 2 surround the semitransparent solar elements 1 as flexible foil the wall of the reactor 3 on all sides, with the nanostructured electrochromic layer 2 between the semitransparent solar elements 1 and the wall of the reactor 3 located. In this embodiment, the light is absorbed from a large solid angle. This embodiment is particularly suitable for large volume vertical air lift bioreactors.

Example 3

According to 3 are bubble columns in semitransparent solar cells 1 integrated. In this embodiment, the bubble columns are used as a battery between upstream planar semi-transparent solar cells 1 with the nanostructured electrochromic layer 2 posed.

Example 4

With the execution after 3 the mode of operation of the reactor was gem. 3 demonstrated.

• – Medientemperatur T = 25–28°C,
• – Begasung v = 5% CO₂,
• – Nährmedien Setlik und ESP

wechselnder Lichtintensität durch vorgeschaltete CIS-Dünnschicht-Solarzellen ausgesetzt.The microalgae strain Scenedesmus sp. 1 was at the following parameters:

• - medium temperature T = 25-28 ° C,
• Fumigation v = 5% CO ₂ ,
• - Culture Media Setlik and ESP

changing light intensity exposed by upstream CIS thin-film solar cells.

At one for Scenedesmus sp. 1 high light intensity of 270 μmol / m ² s without semitransparent thin-film solar cells and a turbulent flow, an active ingredient formation of 5.2 mg per g of biomass was achieved.

At a light intensity of 50 μmol / m ² s at the surface of the SPB and an upstream semitransparent thin-film solar cells (CIS solar modules) the active ingredient formation was 4.9 mg per g of biomass at reduced flow with simultaneous generation of 38 watts per m ^{2 of} thin film solar cell.

1

semitransparent solar cell

2

nanostructured electrochromic layers

3

outer wall of the bioreactor

4

liquid media

5

biomass

6

liquid feed

7

gas supply

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 1997/011154 [0011]
• WO 2000/061719 [0013]
• - WO 2008/079724 [0014]

Claims (11)

Photobioreactors for the cultivation and propagation of phototrophic organisms in the liquid phase by reaction with gaseous, solid and / or liquid additives when exposed to sunlight and / or artificial light for the production of biomass and / or their metabolites and use of excess light energy, characterized in that Photobioreactors are provided with a device for controlling the light transmission and thus the heat input and with semitransparent solar elements. Photobioreactors according to claim 1, characterized in that that the phototrophic organisms are microorganisms, algae, cyanobacteria or higher plant cells. Photobioreactors according to claim 1 and 2, characterized by semitransparent thin-film solar elements used for the photosynthetic active radiation is transparent and the high energy Convert radiation into electrical energy. Photobioreactors according to claim 1 and 2, characterized by opaque or opaque solar elements with a screened coating and remaining zones on the Base material. Photobioreactor according to Claims 1 and 2, characterized in that that only parts of the reactor wall with opaque or opaque Solar elements are provided and the remaining parts as a window to serve for the incidence of light. Photobioreactor according to Claims 1 to 5, characterized that the light intensity acting on the reactor through a specific, in particular nanostructured coating of Reactor, which uses an electrochromic effect, by applying to stain an electrical voltage and the light transmittance and thus to influence the heat input is controlled reduced and the coating acts as a shading element. Photobioreactor according to Claims 1 to 6, characterized that the entire reactor wall, exposed to light incidence surfaces or provide parts of the reactor with semitransparent solar elements are. Photobioreactor according to Claims 1 to 7, characterized that the semitransparent solar elements are geometrically structured rigid or flexible as films adapted to the surface of the photobioreactor are. Photobioreactor according to Claims 1 to 8, characterized that the semitransparent solar elements themselves are the outer ones Form the wall of the bioreactor, on this outside directly or with an air gap to the translucent bioreactor surface are attached. Photobioreactor according to Claims 1 to 9, characterized that the position of the solar elements to the reactor depending on the daylight intensity is controlled. Photobioreactor according to claim 1 to 10, characterized by the use of those produced by the semitransparent solar cells electrical energy for setting certain operating parameters, as for controlling the light transmission, tempering the reactor contents or the feed into external grids.