WO2010031090A1

WO2010031090A1 - Process for fixing carbon and for energy generation

Info

Publication number: WO2010031090A1
Application number: PCT/AT2009/000291
Authority: WO
Inventors: Maximilian Lackner; Manuela Branka
Original assignee: Maximilian Lackner; Manuela Branka
Priority date: 2008-07-28
Filing date: 2009-07-28
Publication date: 2010-03-25

Abstract

The invention disclosed here describes a process for energy generation in power plants by combustion of aquatic biomass. In an advantageous embodiment, bacteria are used for this purpose. In a particularly advantageous embodiment, cyano bacteria and/or E. coli bacteria are used for this purpose. In a further advantageous embodiment, the bacteria comprise a plasmid which produces chlorophyll. The chlorophyll and the metabolism of the bacteria produce sugar and various high-energy compounds such as hydrogen, alcohols, proteins and fats. The bacteria are capable of utilizing the sunlight much more efficiently than plants, for example energy crops or algae. The biomass produced by means of bacteria is utilized thermally. Beforehand, chemical commodities and fine chemicals can also be obtained.

Description

Method of fixing carbon and generating energy

State of the art

80-90% of the world's primary energy is generated by combustion [I]. Much of the energy source is fossil origin. Also, a large part of the basic chemicals are generated from fossil fuels, such as CO, HCHO, H ₂ , CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₂ H ₃ , C ₃ H ₆ , HCOOH, ethanol or ethylene oxide. Rising prices (scarcity of oil) and increased environmental awareness (global warming) have boosted biomass energy production in recent years. The spectrum of available technologies is very wide here; In addition to the direct burning of waste from agriculture, targeted so-called "energy crops" are grown, from which fuels can be obtained.

The biomass-derived fuels are solid (e.g., wood pellets), liquid (e.g., bioethanol, bio-butanol), or gaseous (biogas). The processes for converting biomass into liquid or gaseous fuels are chemical (e.g., gasification of biomass in fluidized bed plants), physical (e.g., squeezing oil seeds), or biological (e.g., anaerobic fermentation). The energy yield from direct combustion is usually best. Through cogeneration, the efficiency can be increased. Energy from biomass is generally environmentally friendly, but the entire chain needs to be considered. For example, methane is much more climate-friendly than carbon dioxide. Thus, leaks in a biogas plant that lead to the release of methane can cause a biogas plant to contribute more to the global warning than, for example, an aerodynamic power plant.

A relatively new branch is energy production from biomass, which can be produced or harvested in the sea, so-called aquatic biomass. This is how algae can be used to produce biodiesel.

Aquatic biomass is advantageous for the following reasons:

- no competition with food, as is the case with energy crops

- high efficiency

- Algae are very frugal and need no special fertilization.

In the field of energy production from aquatic biomass by obtaining high - energy compounds such as biodiesel are a large number of Research institutes and companies. It is known that algae can be used in the sea for the production of biodiesel [2] and for CO ₂ fixation [3], see also patent [8].

DE 2 74 36 18 describes a process for obtaining fuels from plants, algae, bacteria and fungi. CN 101033405 describes the pyrolysis of algae for the production of solid and liquid fuels. WO2007128800 describes a method of converting biomass into liquid fuels and into chemicals.

The efficiency of carbon fixation in high-energy compounds by algae is higher than that of conventional biomass (on the mainland). Therefore, processes that recover biodiesel from algae are considered to have great potential as third generation processes. It can be assumed that combustion processes will remain the dominant energy source for several decades [7].

The conversion of aquatic biomass into, for example, biodiesel or the compression to oils are very complex processes in which not all the energy content of the raw material is used.

The background is that the recovered fuels (oils, biodiesel) have a high energy content per dm ³ and are therefore suitable for energy storage and release in mobile applications.

Energy production in large, stationary, calorific power plants is traditionally done by fossil fuels. Partly also biomass (solids) is burned, mostly in co-firing. Combustion of non-mainland biomass in power plants has so far received no attention.

Disclosure of the invention

The present invention relates to a method for fixing carbon and energy production, comprising the steps:

- Production of aquatic biomass using CO ₂ and sunlight

- combustion of aquatic biomass

According to the invention, aquatic biomass is biomass that can be cultivated, produced, or recovered in waters. These include, for example, algae, fungi and bacteria. Under energy production according to the invention, the production of heat and / or force, such as electricity, understood.

Brief description of the figures

FIG. 1 shows a plasmid for the genetic modification of bacteria. Figure 2 shows the scheme of the method for power generation.

Detailed description of the invention

The present invention is based on the consideration, instead of a complex extraction of biomass fuels from biomass which is easy and cheap to obtain, namely aquatic biomass, to generate energy by direct combustion.

For the purposes of the present invention, "aquatic biomass" is to be understood as meaning biomass which has been produced or produced in water. "Water" here means reactors, basins, lakes, marine waters such as oceans, and rivers of various sizes, both with salt water as well as with fresh water.

The aquatic biomass can be vegetable or animal. In particular, algae, plankton (phytoplankton, zooplankton), grasses, fungi and bacteria have been shown to be beneficial biomass. The aquatic biomass can be naturally occurring biomass or designer organisms (ie genetically modified) organisms, as well as any mixture thereof.

Preference is given to using as aquatic biomass bacteria.

Bacteria grow much faster than algae, so they are predestined for the fixation of carbon from CO ₂ . The biomass thus obtained can then be used according to the invention for environmentally friendly and efficient energy production by combustion.

The bacteria are preferably selected from the group consisting of E coli bacteria and cyanobacteria. Further usable bacteria are those of the groups Chlamydiae, Chlorobi, Planctomycetes, Proteobacteria, Firmicutes and Spirochaetes.

The preferred bacteria are characterized by the fact that they live in water and are as unpretentious as possible.

Some of these bacteria are phototrophic, ie capable of photosynthesis, such as the cyanobacteria. Other mechanisms for generating energy from sunlight are also possible.

In an advantageous embodiment of this patent, cyanobacteria (also called blue-green algae) are used. "Pure" cyanobacteria can be used, but also organisms that have cyanobacteria in leaf cavities, nodules, etc., such as algae ferns (Azolla).

The bacteria used can, for example, be genetically modified via the introduction of a plasmid.

In an advantageous embodiment, cyanobacteria and E-coli bacteria are used with special plasmids. A plasmid is a typically circular DNA molecule that exists in the bacterial cells but does not belong to the bacterial chromosome.

In an advantageous embodiment of the present invention, a Chlorophyllbzw. Chlorophyll-gene-carrying plasmid or a plasmid which produces chlorophyll, introduced into the bacteria (blue-green algae or E-CoIi). Due to the well-known, very efficient protein synthesis performance of the E-CoIi bacteria an enrichment of the cholorophyll protein is achieved.

The bacterium now produces chlorophyll very quickly and efficiently. Under the influence of sunlight, this chlorophyll now produces sugar and / or other organic, energetic substances (carbohydrates, oils, etc.).

The bacteria thus achieve a better utilization of solar energy compared to normal plants.

Specifically, these genetically engineered bacteria, as described below, have the following advantage: Unlike plants (energy crops, algae, etc.), which only so much Producing chlorophyll, as they need to produce the sugar they need, can achieve significantly faster growth with these bacteria. As a result, more biomass from bacteria grows per unit of time and area than from algae or other plants.

As an alternative to or together with the bacteria, algae, fungi or other organisms can be used as the aquatic biomass.

Particularly suitable are algae from the group consisting of green algae, red algae, brown algae, diatoms, gold algae, yellow-green algae, Glaucophyta, Haptophyta, Mouth Fever, Euglenozoa, Dinozoa, Raphidophyceae, Chlorarachniophyta and Picobiliphyta. Picobiliphyta is particularly advantageous because low-salt seawater is sufficient for breeding.

The algae used according to the invention may also be genetically modified.

From the aquatic biomass, basic chemical substances and / or fine chemicals can be obtained before combustion. The basic chemical substances or fine chemicals are preferably selected from the group consisting of sugar, biodiesel, hydrogen, ethanol, carbon monoxide and hydrocarbons.

Prior to the biomass burning step, drying or predrying of the biomass may preferably be carried out.

For drying or predrying of the biomass, the waste heat from the combustion process can preferably be used. Drying is used in the sense of this invention if only one step is involved. If at least a second step follows the drying, the first step or the first steps is called "pre-drying".

Further preferred embodiments are specified in the subclaims.

In the following, the invention will be explained stepwise in more detail with reference to the preferred use of bacteria:

Step 1: Fixation of carbon by aquatic organisms such as bacteria under the influence of sunlight. Production of aquatic biomass

In step 1, carbon is fixed in aquatic biomass. In an advantageous embodiment, the carbon from CO _{2 is} fixed in bacteria.

According to the particularly preferred embodiment of the present invention, modified blue-green algae or E-coli bacteria are used for the fixation of carbon.

The development steps and the introduction technique of plasmids can be found in the current Current Protocols [4] (standard method of the

Microbiology / molecular genetics / chemical analysis). Briefly summarized, the required plasmid in an advantageous embodiment contains the following parts: First, a promoter suitable for bacteria, all exons of the cholorophyll gene with poly-tail and a corresponding coding of an antibiotic resistance for the selection of the plasmid-carrying E. coli or blue-green algae. For an overview, see FIG. 1 (exemplary example).

The abbreviation "Amp" in FIG. 1 means ampillicine resistance

Details can also be found in patent specification [9].

The blue-green algae and / or E-coli bacteria can be kept outdoors or in a suitable breeding pond.

The breeding tank should be such that the temperature is between 10 and 60 ° C (37 ° C is advantageous), the pH between 3 and 11 (advantageously about 8), the NaCl content 0-5% (is advantageous 0.9%) is or can be adjusted.

For rearing before exposure, the following nutrient solution has proven itself:

Casein 10g

Yeast extract 5 g

NaCl 5 g

NH ₄ Cl

KH ₂ PO ₄ * 2H ₂ O 3 g

Na ₂ HPO ₄ * 2H ₂ O 6 g

H ₂ O 90Og-IOOOg

Glucose 4-4Og

MgSO ₄ .7H ₂ O 24.65 g -246.5 g

Other nutrient solutions are possible. The breeding tank may therefore contain fresh water, salt water (seawater) or a mixture thereof. To accelerate the growth, CO ₂ or a CO ₂ -containing gas can be passed through the medium of the breeding tank. This is also advantageous for expelling the resulting oxygen. It is possible to supply exhaust gases or CO ₂ from the subsequent combustion process to the breeding tank or the growth space of the organisms.

The content of bacteria in the breeding tank can be from 0.001 to 98% (mass).

The plasmid produces by reading chlorophyll. This chlorophyll is now in the bacterium, where it is exposed to sunlight, e.g. Sugar produced; This sugar and / or other organic, high-energy compounds are enriched in the bacterium. This enrichment can be continued until the bacterium dies. By acid fermentation, the bacterium can also convert the sugar to ethanol. It is also possible to release hydrogen, as has already been shown for the bacterium Clostridium tyrobutyricum JMl [5].

The high-energy compounds can now be removed from the breeding tank, either when they are in the bacterium or in the solution outside.

The bacteria multiply by cell division at a doubling rate of 10 minutes to 10 hours, typically 3 hours.

It is possible to keep only blue-green algae or E-CoIi bacteria in the breeding tank. In a further advantageous embodiment, there are other organisms in this breeding tank, which produce other high-energy compounds from the metabolic products of blue-green algae or E-coli bacteria, such as H ₂ , ethanol, methanol, CO, HCHO, CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₂ H ₄ , C ₃ H ₆ , HCOOH, esters or lipids.

It is also possible to modify the E-coli bacteria or blue-green algae via plasmids in such a way that they not only produce chlorophyll, but also specifically metabolite products in the desired yield and / or selectivity.

This can be achieved via a common, but also via two or more different plasmids.

It is also possible to produce by means of one or more suitable plasmids hydrocarbons such as oils or biodiesel in bacteria such as E-CoIi or blue-green algae. Ultimately, however, the purpose of the inventive method is the combustion of the biomass obtained. Before that, optional small molecules, referred to as chemical precursors, can be obtained. These include, for example, H ₂ , CO and CH ₄ , but also C ₂ H ₂ , C ₂ H ₄ , C ₃ H ₆ , HCHO and others.

As shown in Figure 2, chemical precursors such as H ₂ , CO and or CH _{4 may be} released and withdrawn during production.

For the purposes of this invention, two ways are possible:

a) Production of aquatic biomass "naturally" from sunlight and / or b) Production of aquatic biomass through anthropogenic influence and support.

By a) is meant, for example, the harvest of naturally occurring organisms in the aquatic environment.

Step 2: Separation of bacterial biomass

The bacteria can be separated from the aqueous breeding solution by various methods (collection, harvesting). Centrifuging, precipitation, flocculation or salting-out, filtering, filtering, sieving, pressing, flotation have proved successful. The water content can be between 0.1 and 99%. In most cases, the biomass obtained is present as a suspension or "slurry".

In the separation, as in step 1, chemical precursors can be released, which can be withdrawn and recycled, for example H ₂ , CO and / or CH ₄ .

Step 3: Processing

This step is optional. It can be separated by various processes according to the prior art, one or more substances or the biomass or a part thereof to be converted.

Possible, for example, fermentation or fermentation. Biogas, hydrogen, etc., can be obtained in this way. Purpose of the treatment is the extraction of gaseous, solid or liquid substances that are not directly supplied to the combustion. The rest of the aquatic biomass goes to step 4. The residence time of the aquatic biomass in step 3 can be up to 2000 hours.

Step 4: Drying / Predrying

The bacterial biomass can be dried or predried as follows:

• By exposure to sunlight

• By using the waste heat from a combustion process.

The former is already known for sewage sludge (Kalogeo process) [6]

Drying means dehumidification, i. the complete or partial removal of water.

In step 4, preferably a predrying or drying of the biomass takes place. At the same time or instead, the temperature of the slurry of aquatic biomass and its pressure can be increased.

The energy for predrying or drying can come from one or more of the following sources:

- solar energy

- Use of waste heat from the combustion process

- Use of geothermal energy

The drying or pre-drying can also be done by dewatering by applying negative pressure or by another suitable method, such as a membrane technology.

After drying or predrying, the biomass can be stored. The moisture content is 0.1 to 99%. In the case of a still high or unchanged moisture content only the temperature and / or pressure of the slurries are increased.

The slurry of biomass and water (nutrient solution, fresh water, salt water, or the like) can be simultaneously brought to elevated temperature and pressure in the drying step. In an advantageous embodiment, these steps are combined. Step 5: Pyrolysis, gasification

By pyrolysis or gasification (optional), a part of the aquatic biomass can be converted to gaseous products (eg CO, H ₂ , CH ₄ ) and removed. The prior art discloses the process of "polygeneration." It is crucial that a solid or liquid residue of aquatic biomass remains, which is fed to step 7.

It is also possible to deposit carbon. This can be used in the chemical industry or it can also be stored.

Step 6: Mechanical processing

In the next step, which is also optional, the biomass can be pressed or ground into pellets, ingots or powder. Also a spray drying is possible. It is possible to add various aggregates in order to allow pressing to handle bulk goods.

Step 7: Combustion

The combustion of the aquatic biomass in a power plant, ie a device for generating energy (heat and / or power such as electricity), is the essential step of the present invention.

It comes here, not known as the prior art, only a single biomass derived from gaseous or liquid component for thermal utilization, but biomass itself (possibly in a discharged form after deduction of eg CO, H ₂ or CH ₄ , see above) ,

The thermal utilization is carried out here by the treated according to steps 1 to 6 biomass.

A catalytic combustion of the biomass is possible. In this case, the biomass may be moist or not at all dried.

Likewise, combustion in an oxygen-enriched atmosphere and combustion at high or low temperatures is possible ("wet combustion", see for example [10]). Combustion is preferably carried out by introducing the biomass into a power plant of the size 0.1 kW to 100,000 MW provided for this purpose. This power plant can be operated continuously. In this case, the aquatic biomass can be burned as the sole fuel, but also as co-firing. A typical suitable technology is fluidized bed combustion or grate firing.

The biomass can, depending on the moisture content, be introduced in different ways.

In an advantageous embodiment of this invention this is done by:

- Injecting dust (particle size about 1 nm to 10 mm). This is typically possible with moisture contents of 0, 1 to 10%.

- Introduction of general cargo (grain size about 1 mm to 10 cm). This is typically possible at moisture contents of 5 to 50%.

- Introduction of biomass suspended in water. Typically, the water / biomass mixture is introduced at elevated pressure (1-300 bar) and elevated temperature (50-400 ° C) and atomized / sprayed to allow rapid evaporation of the water. The heating of the suspension of biomass and water is carried out by solar energy or by the waste heat from the combustion process, as already disclosed above.

It must be ensured that there is a high salt content, especially with marine biomass and biomass obtained by salting out. Above all, chlorine and alkali metals lead to corrosion in the combustion chamber and in the flue gas system.

In the next step, the energy from the fuel is converted into usable energy. This can be done by:

- Heating water in pipes, which are facing the combustion chamber / the flue gas system and run through it. The resulting water vapor can be used in the prior art in a turbine for power generation.

- Condensation of water vapor in the flue gas. This water vapor is essentially the vaporized water from the biomass suspension as well as part of the Combustion products. The condensing can take place directly in a second chamber, or after a turbine, which was driven by the exhaust gas.

The power plant is advantageously operated in combined heat and power. Part of the heat (0-100%) is used to dry or pre-dry the biomass. This is particularly advantageous if no customer for heat is available.

The solar drying can be done according to the prior art based on patent specification [6].

Above all, the combustion of a suspension of biomass and water, also called "slurry", is advantageous, since this slurry has a water content of 1 to 99%.

Due to the high evaporation energy of the water, the combustion temperature is sometimes much lower than in regular calorific power plants. This prevents the formation of thermal NOx.

The pressure in the combustion chamber can be from 0.1 to 100 bar, the temperature 100 to 2200 ° C.

The slurry introduced into the combustion chamber in an advantageous embodiment of this disclosed invention has a pressure of 1 to 2000 bar (absolute) during atomization into the combustion chamber. Its temperature can be between 4 and 800 ⁰ C, advantageously between 50 and 400 ° C.

It is possible to carry out the combustion in an atmosphere of 5 to 100% oxygen. By exhaust gas recirculation, the heat energy of the exhaust gas can be further exploited.

It is also possible to accelerate the combustion through the use of catalysts.

The combustion exhaust gases can be introduced into the breeding tank (sea, lake, river, etc.) to accelerate the growth of the biomass by raising the temperature and / or CO ₂ .

CO ₂ sequestration is also possible, see the prior art.

The individual steps as well as the power plant technologies can be regarded as state of the art. According to the state of the art are power plants, especially large, caloric, onshore (onshore) and are stationary. If the fuel is harvested in the sea or on a suitable body of water, it may be advantageous to bring the power plant closer to the place of production.

This can be done by installing the powerplant offshore on a suitable platform or even mobile, such as by building on a ship-like body. Especially in the case of a stationary "offshore power plant", it is possible and advantageous to create "breeding containers" in the vicinity in which the biomass can grow and be harvested.

As breeding tanks u.a. shallow containers, for example seawater-flooded areas of offshore deserts. If fluidized bed technology is used for combustion, even larger amounts of sand in the slurry do not interfere.

FIG. 2 schematically illustrates the above-described steps 1 to 7 of a preferred method according to the invention.

Bibliography :

[1] Jürgen Warnatz, Ulrich Maas, Robert W. Dibble, Combustion: Physical and Chemical Fundamentals, Modeling and Simulation, Experiments, Pollutant Formation, Springer, Berlin, 4th Edition, ISBN 978-3540259923 (2006).

[2] Han Xu, Xiaoling Miao, Qingyu Wu, High-quality biodiesel production from a microalgae Chlorella protothecoides by heterotrophic growth in fermenters, Journal of Biotechnology 126 (4), 499-507 (2006).

[3] Lewis M. Brown, Kathryn G. Zeiler, Aquatic biomass and carbon dioxide trapping, Energy Conversion and Management 34 (9-11) 1005-1013 (1993).

[4] http: //www.currentprotocols.corn/WileyCDA/ (2008).

[5] Ji Hye Jo, Dae Sung Lee, Donghee Park, Jong Moon Park, Biological hydrogen production by immobilized cells of Clostridium tyrobutyricum JMl isolated from a food waste treatment process, Bioresource Technology 99 (14), 6666-6672 (2008).

[0001] EP 1 378 494 (priority AT 3442002), Process and apparatus for processing biogenic residues, in particular sludges (Process and apparatus for treating biogenic residues, in particular sludges), Tecon Engineering GmbH, 07.01.2004.

[7] M. Lackner, F. Winter, B. Geringer, F. Winter, M. Lackner, Chemistry in the Engine, Chemistry in Our Time, 39 (4), 246-254 (2005).

[8], EP 1928994, Method, apparatus and system for biodiesel production from algae, Solix Biofuels lnc, 11.06.2008.

[9] EP1924601, Expression of Proteins in E. coli, Novo Nordisk AS, 28.05.2008

[10] US3920506, Wet combustion of waste liquors, 18.11.1975.

[WO2007128800, Process for the conversion of biomass to liquid fuels and specialty chemicals, Bioecon Internat. Holding NV, 15.11.2007.

Claims

Claims:

1) Method of fixing carbon and generating energy comprising the steps of:

- Production of aquatic biomass using CO ₂ and sunlight

- combustion of aquatic biomass.

2) Method according to claim 1, characterized in that the aquatic biomass is produced in the sea and / or in breeding tanks.

3) Method according to claim 1 or 2, characterized in that the aquatic biomass is selected from the group consisting of bacteria, algae, plankton, fungi, grasses and mixtures thereof.

4) Method according to claim 3, characterized in that bacteria selected from the group consisting of E coli bacteria and cyanobacteria are used.

5) Method according to one of claims 3 or 4, characterized in that the bacteria were genetically engineered via introduction of a plasmid.

6) Method according to claim 5, characterized in that the bacteria produce chlorophyll via the plasmid.

7) Method according to one of the preceding claims, characterized in that from the biomass prior to combustion chemical precursors and / or fine chemicals are obtained.

8) Method according to claim 7, characterized in that the chemical precursors or fine chemicals from the group consisting of sugar, biodiesel, hydrogen, ethanol, carbon monoxide and hydrocarbons are selected.

9) Method according to one of the preceding claims, characterized in that prior to the step of combustion of the biomass drying or predrying of the biomass is carried out.

10) A method according to claim 9, characterized in that the waste heat of the combustion process is used for drying or predrying of the biomass. 11) Verfaliren according to one of the preceding claims, characterized in that the combustion takes place in a power plant with a capacity of 0.1 kW to 100,000 MW.

12) Method according to one of the preceding claims, characterized in that the combustion is carried out in an oxygen-enriched atmosphere.

13) Method according to one of the preceding claims, characterized in that the exhaust gas of the combustion is introduced into the aquatic biomass in order to increase the growth of the same by temperature and CO ₂ fertilization.

14) Method according to one of the preceding claims, characterized in that the combustion takes place catalytically.

15) Method according to one of the preceding claims, characterized in that the aquatic biomass between 0.1 and 100% in co-firing to conventional fuels such as petroleum, oil, gas or coal is used.