ES2528388B1 - Procedure for obtaining biomass and derived products from unicellular algae, and installation for its execution - Google Patents

Abstract

Procedure for obtaining biomass and derived products from unicellular algae, and installation for the execution of the same. # The present invention relates to a process comprising all the necessary steps starting from a culture of unicellular "prokaryotic" algae dissolved in aqueous medium, all the elements necessary for its cultivation and development and by means of the external contribution of nutrients, CO {sub, 2} and sunlight, a biomass is obtained by flocculation and subsequent centrifugation procedures with a degree of humidity between 50% and 90% and subsequently proceed to a drying stage that prepares said biomass for the extraction of lipids by supercritical fluids, with possible cell pre-rupture if the microalgae requires it, obtaining various fractions of final elements that include products of added value as well as a bio-oil or biocrude. The process has all the necessary equipment and elements to be able to define the set as biorefinery, since all the products generated are reused and different compounds are obtained with different applications and at different stages of the process.

Description

OBJECT OF THE INVENTION

The present invention is included in the field of Ficotechnology, or Biotechnology with origin in algae or microalgae. The main application focuses on the contribution of sunlight, nutrients and CO2 to a single-cell microalgae culture existing in a photobioreactor or photobioreactor field in a closed system and more specifically in vertical and / or vertical inclined photobioreactors. With the process described below, a biomass will be obtained from which lipids with high fatty acid contents will be extracted, which in turn will have a final destination as food and pharmaceutical products, in addition to those of transforming the bio-oil into biofuel .

The present process presents improvements with respect to previously existing processes, which make it more energy efficient speaking, apart from reducing polluting emissions to the environment after converting CO2 into biomass. The rate of capture and conversion of C02 exceeds 95%, being much higher than what exists in the state of the art. The returns of each of the separation processes are treated independently to guarantee their possible return to the culture medium. It also includes an automatic internal tube cleaning system that greatly improves the efficiency of the process.

The corresponding installation for the implementation of the procedure itself is also object of the invention.

BACKGROUND OF THE INVENTION

According to the 2012 annual report of the Food and Agriculture Organization of the United Nations (FAO), in the next decade the production of food with aquaculture will exceed in production that of beef, pork and poultry. In 2011, capture fisheries and aquaculture supplied the world with 154 million tons of fish, of which 90% were for human consumption, with an average of 18 kg per capita.

In 2000, only 15% of total world fish production came from aquaculture, in 2010 it was already 40%. Capture fishing remains stable, while aquaculture is absorbing all the increases necessary to supply the growing population, as well as their growing energy needs. Lyophilized biomass from microalgae is postulated as the best solution to support this increase in production in many of the 600 species that are bred in captivity.

On the other hand, with the worldwide implementation of second-generation biofuels, from land crops, such as palm or soybeans, an escalation in prices of these basic products was generated that led to and still has an impact on food crises in the countries poorer The implementation of biorefineries for the production of third generation biofuels, such as those from microalgal biomass, solve this problem.

Document ES 2370583 A 1 describes different types of photobioreactors and accumulation deposits, clarified and others, not including the rest of the process until obtaining biomaterials and other final products, the photobioreactors used in it are not the same as those indicated herein. Patent does not include improvements in tempering, collection of surplus gases and automatic internal cleaning of pipes.

The patent application EP 2371940 A1 discloses a process and an installation for the production of biofuel and CO2 reduction, using non-annular tubes and with long lengths, preferably horizontally and so that it takes us to large cultivation areas. Likewise, the energy efficiency of the process is not competitive with that set forth in the present application, because large movements of fluid are needed to avoid the known fouling (or adhesion of microalgae to the tube walls) with the consequent loss of performance effectiveness by reduction of solar irradiation, and with it large energy consumption. The drying stage contemplated in said application, between the phases of biomass separation and the extraction of compounds, is also energy inefficient, since it is carried out by filtration, which is economically unfeasible. This application basically focuses on the capture and conversion of CO2, but the rest describes it far above.

Document US 2007048859 Al includes the phases of cultivation of microalgae from the cultivation area with photobioreactors, the capture of COz and the subsequent treatment of biomass until obtaining a final product based on biofuel. For this, it uses photobioreactors without a cleaning system and in a single arrangement, conventional drying systems and a single thermochemical treatment to obtain the biofuel without additional processes to obtain value-added products. All this is planned without any combination of species or reuse rejection.

The document ES 2356653 A 1 describes an invention with conical lotobioreactors and submerged inside a tank, being an application totally different from that set forth in the present invention.

International patent application WO 2007147028 A2 talks about the equipment necessary to capture CO2 and introduce it into photobioreactors, mentioning a separation process, and describes a final biomaterial extraction, although the constituent elements of the CO2 capture system are explained in the claims and its introduction in photobioreactors, as well as the different photobioreactor options. The mentioned cycle does not include the biorefinery concept of this patent.

Patent application US 4868123 A refers only to photobioreactors, but does not introduce the improvements mentioned in this application that make it much more efficient. This document refers only to one type of photobioreactors for microalgae cultivation with different functioning to that set forth in the present invention, not including automatic cleaning system or possibility of all airwater operations, in parallel and cross, or surplus recovery to do more Efficient the process. Additionally, it makes no mention of any type of process subsequent to the cultivation of microorganisms.

There are many technical documents and patents that teach us, in the field of microalgae, the different possibilities of photobioreactors, both in materials used and in arrangement and mode of operation, for example the documents "Photobioreactor: light regime, mass transfer, and scale-up ", Joumal of Biotechnology, 70,

231.47 (1999) by Malina Grima, E., Acién Fernández, F .G. García Carnacha, F. and Chisti; or

"Scale-uo 01 tubular photobioreactors", Joumal 01 AppliedPhycology, 12, 355-68 (2000), by Malina G., Acién Fernández, FG "García Gamacha, F., Garnacha Rubio, F., and Chisti; or" Photobioreactorsproductionsystemsforphototrophicmicroorganisms ", Applied Microbiology and Biotechnology, 57, 287-93 (2001), de Pulz, O .; or" Microalgalreactors: a review of enclosedsystemdesigns and perlomances ", BiotechnologyProgress, 22, 1490-506 (2006), of Carvalho, AP, Meireles , LA, Maleata, FX; or "OesignPrineiples 01 photobioreactorsforcultivation of unicellular algae" by D. Ciernen s Pasten, Institute of LifeScienceEngineering, Division of BioprocessEngineering, University of Karlsruhe, Strasse am Forum 8, 0 -76131 Karlsruhe (Germany), 001: 1 0.1 002lelse.200900003, May 29, 2009, with all of them parts of the process and elements that are current state of the art are shared, but in none the internal tempering is used nor does it carry the automatic cleaning system or the upper collection of CO2 surplus to improve efficiency.

On the other hand, there are also innumerable technical documents that describe the crop harvesting process and subsequent thermochemical treatments to obtain final products, see "HydrothermalTreatment of Unicellular Algae: Evaluation of theProcess as ConversionMethod in anAlgaeBiorefinery Concept" (Laura García Alba, Cristian Torri, ChiaraSamori, Jaapjan van der Sped, DanieleFabbri, Sascha RA Kersten, and Derk WF Brilman (2011) or Thermo-ChemicalConversion of BiomassGroup, Faculty of Science and Technology, University of Twente, PO Box 217, Enschede, TheNetherlands). Processing steps are shared with this patent but the sequencing and the methods used are not the same.

Finally, there are also many technical documents that list the applications of the final products to be obtained from microalgae, whether they are in the form of bio-oils, such as biofuels, gases and / or value-added products for any energy, nutritional and / or application. or pharmacological, such as "Encyclopedia 01 bioprocesstechnology: fermentation, biocatalysis and bioseparation", Wiley, 395-419 (1999), by Trecidi, MR, Flickinger MC, Drew SW .; or "Selectiveextraction 01 caarotenoidsfromthemicroalgaDunaliella salina withretention 01 viability" (Hejazi MA, from Lamarliere e, Rocha JM, Vermue M, Tramper J, Wijffels RH; BiotechnolBioeng. 2002-Jul); or in "Praduction 01 cell mass and eicosapentaenoic acid (EPA) in ultra high cell density cultures o, Nannochloropsis Sp. (Eustigmatophyceae) (NingZoy, Chengwu Zhang, Zvi eohen & Amos Richmond, 2000; Eurapean Journal 01 Phycology, 35: 2, 127-133).

DESCRIPTION OF THE INVENTION

In view of the cited documents, the present invention aims to improve the efficiency of the processes of obtaining biomass from unicellular algae and extraction of products of all kinds, from the point of view of biorefinery, basically speaking of oils, biofuels, gases and value-added products usable for any subsequent application. The improvements introduced in terms of recoveries of raw materials, as well as automatic cleaning systems and the final sequencing of production of final products, together with the recovery of the rejections of the process for their treatment and subsequent reintroduction in the water and gas lines , as well as through improvements in facilities designed for this purpose, make it much more efficient than what exists in the state of the art and more complete.

Antibiotics or fungicides are not used in the process of the invention, so that the products obtained have a higher quality than those obtained by other processes.

More specifically, the invention relates to the process for obtaining biomass, as well as to an installation or biorefinery, which begins with the integral conversion of greenhouse gases, which feed a microalgae culture in an aqueous medium, passing through the harvested from them and the subsequent extraction of lipids and other components, with subsequent industrial use in the energy and nutritional sector, both human and animal, through the ultra-intensive cultivation of unicellular algae in aqueous medium, sunlight and nutrients, all this through closed cycle and use of all surpluses in each of the stages. The realization of the final part of the process by means of supercritical fluids using C02 as a drag element of the lipids with the possibility of pretreatment of cell pre-rupture according to the species of microalgae that is being cultivated is achieved, achieving a selectivity of the

same much higher than the one that has existed so far with conventional procedures for extraction with chemical solvents, the efficiency of the process is also much higher and the total costs are equally lower as well as the environmental impact of avoiding the massive use of conventional solvents. The products obtained start with the biomass that can be atomized, lyophilized or used directly to feed marine species, then proceed further af ** the subsequent extraction of fatty acids and / or antioxidants with high nutritional and economic value, with subsequent applications in the nutritional, cosmetic or pharmaceutical industries, to end with a biocrude that can be converted into biofuel through a final thermal liquefaction treatment or used as a food product for animals and / or fish after the extraction of value-added products.

Therefore, the invention relates to an industrial process that will initially produce an algal biomass and subsequently another series of final products from it, by means of an installation in which the following operational phases are defined:

filling of photobioreactors with sea or brackish water, as a base medium for the cultivation of algae; injected into the photobioreactors, at least one strain of a species of unicellular algae, forming the culture; injected into the photobioreactors, and jointly or separately, greenhouse gases (C02 compulsorily) and compressed air, in accordance with the needs of the latter for efficient photosynthesis, establishing an optimal turbulence generated by the air that is introduced by the base of the photobioreactors, between outer tube and inner tube. crop recirculation between the tubes that make up each photobioreactor, according to a homogeneous process within each group of photobioreactors, with a flow rate between 10% and 50% of the total existing crop volume. injected of nutrients in the proportion required by the crop, to collaborate in the achievement of an optimal reproduction of the micro algae. extraction of part of the crop and accumulation of it with an optimal concentration of microalgae, in an accumulation tank; (between 1 and 25% daily, depending on the reproductive conditions that have occurred during the day, in great dependence on the weather conditions that favor photosynthesis).

chemical separation of crop products, in one or several stages, and later

concentration thereof;

return of all leftovers (flocculates or rejections) of culture obtained in the

chemical separation and disinfection and filtration treatments in tanks

independent and subsequent passage to a feed tank prior to cultivation;

mechanical separation by centrifugation of the concentrated culture in the stages

above to get wet biomass, with a water content between 50%

90%.

return of the surplus or rejection or flocculation obtained in the previous stage, towards a

clarification tank and shipment of this crop, after a filtration process and

disinfection, to the feeding tank, all according to a closed process and with

minimum consumption of fresh water;

Pre-drying of biomass through refractive windows and / or solar dryers,

to achieve a dry weight of biomass greater than 95%, as the final product

suitable for further processing, atomization and / or lyophilization depending on the

performance of the previous drying processes mentioned.

Pretreatment of pre-rupture of the cell wall, by cavitation,

grinding or acid hydrolysis, depending on the size of the microalgae and the species, in

definitive depending on the hardness of the cell wall to enable efficient

extraction of fatty acids and other value-added products, without damaging them.

lipid extraction from dry biomass, using supercritical fluids with

CO2, to achieve an important selectivity on valuable products

added obtained, said process being carried out at a temperature comprised

between 2002C and 3502C, and at a pressure between 160 bars and 600 bars, with

periods of time between 25 and 90 minutes per cycle;

transformation of the rest of the biomass after the previous extraction either by

thermal liquefaction for biocrude or sale of biomass for food purposes for

animals or fish feed.

According to another characteristic of the invention, it is provided that the product of each of the returns obtained in the previous phases be stored in a previous unit with treatment by stirring, aeration, supply of compressed air and CO2, as well as supply of nutrients and filtration and disinfection treatment, prior to its passage to the feed tank and replacement to the cultivation area, after each of the extractions.

On the other hand, the current of CO2 gases entering each photobioreactor, comes from a combustion source or from a greenhouse gas accumulation tank, the CO2 surplus being returned back to the corresponding photobioreactor, when the conditions of realization of photosynthesis are not optimal.

Said stream of CO2 gases is injected in an amount between 0.01 m 3 per m 3

of culture and l m per m 3 of culture, at intervals between 10 and 60 seconds per minute.

As for the crop, it is introduced through the upper part of the photobioreactor, being collected from the bottom and mixing between each group of photobioreactors with the same electropump, the culture conditions being the same for the whole group, achieving a perfect mixture of nutrients, from crops with different irradiations and therefore with different light passages, all with a recirculation flow of between 1 and 50% of the total crop volume.

The quantitative is maintained in the range of temperatures between 10l! C and 45 \ C, achieving a tempering thereof through a primary circuit that runs inside the annular and concentric tubes that form each photobioreactor.

In this way, each time the optimum microalgal concentration, characteristic for each species, is achieved, but, greater than 100 million cells / ml, between 1 and 25% of the photobioreactor culture is extracted, in a period of between 1 and 4 hours.

At the same time, the same amount of culture extracted from photobioreactors is introduced, coming from food tanks that in turn collects all the rejections or leftovers from the different processes carried out in the crop until obtaining the final products, properly filtered and eliminated. the organic load and with a certain contribution of fresh salt water also filtered and disinfected conveniently, being the treated water added of nutrients in adequate proportion, as well as of nitrogenous salts such as ammonium, nitrates, phosphates and other trace metals.

In order to carry out the procedure just described, an installation is provided, provided, as is conventional, with a system of separation of the biomass from the crop and the crop to a series of photobioreactors in which the unicellular algae are introduced for its cultivation, with injection of CO2, compressed air and appropriate nutrients, all in an aqueous medium with sea or salt water, with the particularity that each photobioreactor is formed by two concentric tubes, between which a chamber or hole is established for the culture, as well as for CO2 and compressed air, said photobioreactors being sealed tightly by an upper cover and a lower base, with the particularity that each photobioreactor is associated with a hydraulic system formed by a CO2 inlet system and a compressed air inlet system, incorporating in the upper part an automatic recovery system of CO2 surplus or evacuation to the oxygen atmosphere, presenting such a superior recovery system an outgasser or outlet tube with a sensor and a three-way solenoid valve, whereby the recovery of CO2 is achieved for its application back to the inlet system by means of a pipe and system compression if necessary or for the evacuation of oxygen into the atmosphere, as appropriate, all this to ensure a 95% CO2 fixation performance.

Additionally, the installation includes an internal culture tempering system, based on a recirculation circuit that, in combination with electric pumps, geothermal heat pumps or similar, solenoid valves, valves and complementary elements, constitute a primary tempering circuit with energy exchange without the intervention of an exchanger, in which the crop recirculates between different photobioreactors to homogenize their properties between them.

Another feature of the installation is that it includes an internal automatic cleaning system, consisting of plastic pipes equipped with multiple and small holes for the exit of a cleaning agent that affects the inner side of the inner and outer tubes that form each photobioreactor, producing the cleaning of that inner face of said tubes in contact with the crop.

DESCRIPTION OF THE DRAWINGS

To complement the description that will then be made and in order to help a better understanding of the features of the invention, according to a preferred example of practical implementation thereof, a set of drawings is accompanied as an integral part of said description. where, for illustrative and non-limiting purposes, the following has been represented:

Figure 1.- Shows the scheme corresponding to the blocks that establish the whole procedure and installation to obtain biomass and products derived from single-cell algae.

Figure 2.- It shows a section of the photobioreactor that is part of the installation as a whole, with its hydraulic system, automatic entry system for greenhouse gases and compressed air, as well as automatic system for recovering excess gases.

Figure 3.- It shows an enlarged detail of an upper part of the assembly represented in the previous figure, where the automatic CO2 recovery system can be seen in case the efficiency of the crop fixing process does not exceed 95 %.

Figure 4.- Shows another section of a part of the photobioreactor with the internal tempering system of the crop.

Figure 5.- Shows another sectional view of a part of the photobioreactor with the automatic internal cleaning system.

Figure 6.- Shows a plan view of the assembly represented in the previous figure.

Figures 7 and 8. - They show two details enlarged, in plan and elevation, of the way to perform the internal cleaning of the tubes of the photoreactor.

PREFERRED EMBODIMENT OF THE INVENTION

According to the scheme corresponding to the installation by means of which

perform the process of the invention, and shown in Figure 1, say that in said

Installation and corresponding process establish the following operating blocks:

A collection unit (1) that collects and transfers greenhouse gases (COd from an emitting source (2), foreseeably industrial, including a unit for adaptation of the gases prior to their supply to the crop, basically the following gases in addition to CO2: SOx and NOx_There is a reserve unit (3) in case these gases are not enough, this reserve can be used.

An air compression unit (4) and adaptation of gases with incorporation into a cultivation area (5, 5 '), independently of that of greenhouse gases (C02).

An additional system for collecting or recovering excess CO2 and / or oxygen,

which will be explained later, completing the primary introduction system of

CO2, so that in case the surplus of CO2 is high by the

momentary culture conditions, said excess CO2 is reintroduced to the

crop in order to guarantee a minimum of 95% efficiency in capture and

conversion into CO2 biomass. When photosynthesis is being performed it is fixed

CO2 and when efficient is produced, with the photobioreactor design reflected in

The present patent, an index of conversion into biomass with superior efficiency

95% Depending on the type of species used, the biomass that is produced varies

as a result of the fixation of 1 kg of CO2, but it can be used as a value

intermediate that for every 1 kg of biomass obtained 1.8 kg of CO2 has been set (at a

100% efficiency). When photosynthesis is being performed at optimal

conditions, O2 is released into the atmosphere, not losing CO2 from the top

of photobioreactors. The C02 recovery system will reintroduce it to the

crop when the volume coming out of the degasser from the top of the

photobioreactor is greater than the value set according to the cultivated species, but always meaning that the process has an efficiency of 95% or higher, that is, that of every 1 kg of CO2 that is introduced to the crop, at least 0.95 kg become biomass later and only emit to the atmosphere O, 05kg.

A system for collecting seawater and / or brackish water, with its subsequent filtration, antibacterial treatment and accumulation in accumulation tanks (6), all in such a way that the capacity of fresh water volumes must be between 1/15 and 1/10 with respect to the total capacity of the installation, being much lower than that required in other conventional systems, due to the incorporation of return means that allow its reuse.

An automatic cleaning system of the corresponding tubes that form the photobioreactors, which will be explained later, allowing the performance to be very high in terms of solar light collection and thus an optimal photosynthesis and a greater production of biomass

A pipe system that forms a hydraulic network for cultivation, with two air networks, one for greenhouse gases (C02 mainly) (26) and another for compressed air (27), as will also be explained later.

A tempering system (36) that avoids the use of exchanger and secondary circuit required in other conventional installations, thereby avoiding losses. This system will also be explained later.

A system of pipes (42) for cultivation that interconnects all the elements between the cultivation zone and the extraction and replacement zone towards the accumulation tanks (6).

A disinfection system, based on microfiltration, ultraviolet, ozonation and active carbon filters, in order to avoid contamination of the crop and thereby achieve absolute control of the process, incorporated into all the returns that occur in each of the processes The values for each of the treatments are microfiltration up to 0.8 microns, ultraviolet between 10 and 70 mJ / cm2 and ozonation with values between 1 and 5 gr / h x m3.

A nutrient injection system in the crop to favor, along with the contribution of CO2 and natural light, the rapid cell growth of the crop, which is carried out both in the feed tank (11) and in the accumulation tank (6) of fresh water.

An accumulation system formed by the accumulation tanks (7), for the extracted crop, with agitation and air supply to avoid the deterioration of the crop. Daily between 1 and 20% of the total crop is extracted depending on the conditions that have occurred for the realization of photosynthesis during that day.

A system of treatment of the culture by chemical filtration and flocculation, which corresponds to the blocks (8, 9), taking place a chemical separation and going to the next stage of centrifugation (10) only between 5% and 15% of the total of volume of culture extracted, returning the rest of the volume of culture, called rejection volume, to respective return tanks (8 '. 9'), establishing in these a flocculate return system, with agitation, air supply and media filtration, solenoid valves, sensors, electric pumps and treatment system to remove organic matter. Of all the rejection deposits for each of the processes, it is passed to the food tank (11) which will be the one that, with the contribution of fresh water, the same amount of crop that has been extracted is filled daily, between the 1 and 25% of the total crop volume of the plant.

A centrifugation system that corresponds to a mechanical separation, according to the block (10), which is carried out at low revolutions so as not to alter the cell wall of the microalgae and thereby allow subsequent treatment. In said centrifugation process or mechanical separation process, microalgae with a wet base between 50% and 90% of water content are obtained.

A return system of the clarified obtained in the centrifugation phase with stirring, this return system that corresponds to the reference block (10 '). This clarified or return volume will be returned to the crop after the relevant ultraviolet disinfection and ozonation systems, as well as microfiltration. The values for each of the treatments are microfiltration up to 0.8 microns, ultraviolet between 10 and 70 mJ / cm2 and ozonation with values between 1 and 5 gr / h x m3.,

A wet biomass drying system corresponding to the block (12), by appropriate dryers, such as refractive windows or solar dryers, system corresponding to the reference block (13), also includes the possible atomization and / or lyophilization phases Depending on the results obtained with the previous processes, the drying phase is planned to provide a dry biomass, with a humidity index of less than 5% and which will be able to move on to a next stage or process of extraction of foods. , according to block (14), to obtain value-added product according to block (16) and to subsequently obtain a biocrude after a final thermal liquefaction process or direct sale of the biocrude without that industrial process, for animal use or in fish farms ( 17). It could happen, depending on the cultivated species, that the process of extracting lipids by means of supercritical fluids with CO2 required a prior treatment of cell pre-rupture by cavitation, grinding or acid hydrolysis. After the extraction of lipids (14) there is also a rejection or flocculate that can be partially recovered to reintroduce back to the culture, by means of the accumulation deposit of this phase (15), from which it will be transferred to the general food supply tank. Photobioreactors (11), the fluid that reaches this reservoir is free of organic charge and conveniently filtered and disinfected.

A collection system for accidental spillages and leachates.

The different systems referred to, for their correct and efficient operation, are complemented with interconnecting conduits or pipes, filters, electrovalves, electro pumps, sensors and other necessary elements, complementing the installation with a system of photovoltaic solar panels to heat water, as well as for other functions and to generate electricity for self-supply of the installation itself.

As for the practical materialization of each of the photobioreactors (19), according to figures 2 to 6, it is based in each case on two concentric tubes, one inside (20) and one outside (2 1), among which Find the crop itself and through which compressed air and / or greenhouse gases (C02) will run, observing in the detail of the figure

ES 2 528 388 Al

3 the culture (22) between said concentric tubes (20, 21).

The photobioreactor (19), as a whole, comprises an upper hydraulic system (18) and a lower hydraulic system (23), said hydraulic system joining the photobioreactors (19), these being arranged on a rigid support (41), which It provides the necessary height so that the entire installation of lower pipes does not need to be completely buried.

It is necessary to highlight that the photobioreactors have their outer tube (21) transparent and with ultraviolet protection, as well as inner non-stick layer, while the inner tube (20) can be transparent or opaque and not carry ultraviolet protection, but if an inner non-stick protection , so that between the non-stick protections of both tubes (20, 21) is where the crop is located (22), each photobioreactor (19) being complemented with the top cover (24) and bottom base (25) that close tightly to each of said photobioreactors (19), so that they are grouped in the same structure in different positions, depending on the geographical location of the installation and the species to be cultivated, as well as the final products that are desired obtain, to form the whole of the installation, being able to count the installation with between 1 and 30,000 photobioreactors, being the distance between the outer tube (21) and tube inside

(20) of each of them less than 10 cm, preferably less than 5 cm., While its length exceeds 8 meters, making the ratio between volume and surface occupied of this type of photobioreactors for microalgae cultivation, is much more efficient than what exists in the state of the art, obtaining values that reach 250 liters / m2.

At the same time, it is worth mentioning the fact that the crop is maintained in the temperature range between 10ll C and 4511C, achieving a tempering of the same through a primary circuit that runs inside the annular and concentric tubes that form each photobioreactor.

In addition, Figure 2 shows the CO2 input system (26), mainly CO2, consisting of its network of pipes, diffusers and solenoid valves, directly feeding each and every one of the photobioreactors (19), also observing the system Automatic compressed air inlet (27), consisting of its network of pipes, diffusers and solenoid valves, directly feeding each and every one of the photobioreactors (19).

As for the system for recovering excess greenhouse gases (C02), it comprises a three-way motorized valve (28) coupled to a degasser or upper outlet tube (29), in which a sensor (30) has been established ) of CO2, returning, according to arrow (31) of the detail of figure 3, said CO2 back to the crop, and where appropriate allowing the CO2 to enter the atmosphere, according to arrow (32) indicated in that figure 3 , and logically through the three-way valve (28). The recirculation system described is complemented by a system of pipes, solenoid valves and compression system (33), if necessary, logically associated with that CO2 recovery system described above. The pH sensor that each photobioreactor or group of photobioreactors has will be the one that will give the order to send more or less CO2 to the crop, the optimal pH value varies depending on the species but will be between 6.5 and 8.

Figure 4 shows what is considered as an internal tempering system of the crop, showing a group of photobioreactors (19), with their lower supports (41), and the microalgae culture recirculation system (34), formed by pipes, valves, solenoid valves, electric pumps and other elements that allow the crop to mix between the different photobioreactors (19), showing in this figure 4 how the crop is in the ring between the outer tube (21) and the inner tube (20) already mentioned, all in such a way that the tempering system itself will comprise conventional heat pumps, either cooled by air or water,

or geothermal heat pumps (35) and that provide the necessary heat / cold so that the crop is in the optimum temperature range, depending on the species to be cultivated.

There is also a system for supplying the tempering fluid (in general, fresh water with the possibility of some type of additive depending on the climatic conditions) (36) that acts as the primary tempering circuit and which is the one that directly leaves the pump. heat and circulates through the inner hollow of the annular columns that form the different photobioreactors. The energy exchange takes place directly using the inner part of the inner tube (20) of each photo-reactor (19) as an exchanger, no additional exchanger being necessary in the system. Obviously, as in the previous cases, pipes, solenoid valves, valves, sensors, electric pumps and other elements necessary for the proper functioning of the aforementioned internal tempering system of the crop will be included.

Figures 5, 6, 7 and 8 show the automatic interior cleaning system, where the top of a photobioreactor (19) is shown in Figures 5 and 6; Figures 7 and 8 correspond to sections of the same photobioreactor (19), with the internal tubes (20) and external 5 (21), between which the crop circulates, the automatic cleaning system comprising circular and concentric plastic pipes with the tubes that make up the walls of the vertical and / or inclined annular lotobioreactor (37) with multiple holes (38) of small diameter, through which the cleaning agent (39) leaves. In figure 5 an automatic collection device (40) of the plastic pipes can be seen with a

10 pressure between 2 and 5 bar (37), while in figure 8 it can be seen as the cleaning agent (39) that exits through the holes (38) of the plastic pipes (37), affects the internal surface of the inner (20) and outer (21) tubes, in contact with the crop, and whose surfaces are susceptible to fouling by fouling or adhesion of the microalgae.

Claims (11)

1.-Procedure for obtaining biomass and derived products from unicellular algae, based on the cultivation of microalgae in aqueous media, with harvesting of them and subsequent extraction of lipids and other components, carrying out the process from photobrioreactors Tubular annular, vertical and / or inclined, with contribution on the cultivation of CO2 as a greenhouse gas, with enrichment nutrients and using seawater or brackish water, characterized in that it comprises the following operational phases: filling of photobioreactors with sea or brackish water, as a base medium for the cultivation of algae; injected into the photobioreactors, at least one strain of a species of unicellular algae, forming the culture; injected into the photobioreactors, and jointly or separately, greenhouse gases (C02 compulsorily) and compressed air, in accordance with the needs of the latter for efficient photosynthesis, establishing an optimal turbulence generated by the air that is introduced by the base of the photobioreactors, between outer tube and inner tube. crop recirculation between the tubes that make up each photobioreactor, according to a homogeneous process within each group of photobioreactors, with a flow rate between 10% and 50% of the total existing crop volume. injected of nutrients in the proportion required by the crop, to collaborate in the achievement of an optimal reproduction of the micro algae. extraction of part of the crop and accumulation of it with an optimal concentration of microalgae, in an accumulation tank; (between 1 and 25% daily, depending on the reproductive conditions that have occurred during the day, in great dependence on the weather conditions that favor photosynthesis). chemical separation of the crop products, in one or several stages, and subsequent concentration thereof; return of all crop leftovers (flocculates or rejections) obtained in chemical separation and disinfection and filtration treatments in independent tanks and subsequent passage to a feed tank prior to cultivation; mechanical separation by centrifugation of the concentrated culture in the stages above to get wet biomass, with a water content between 50% and 90%. return of the surplus or rejection or flocculation obtained in the previous stage, to a clarification tank and shipment of this crop, after a filtration and disinfection process, to the feeding tank, all according to a closed process and with minimum consumption of fresh water ; Pre-drying of the biomass by means of refractive windows and / or solar dryers, to achieve a dry weight of the biomass greater than 95%, as a final product suitable for subsequent processing, atomization and / or lyophilization depending on the performance of the drying processes Previously commented. Pretreatment of pre-rupture of the cell wall, by cavitation, grinding or acid hydrolysis, depending on the size of the microalgae and the species, in short, depending on the hardness of the cell wall to enable efficient extraction of fatty acids and other value-added products, without damaging them. extraction of Ifpids from dry biomass, by means of supercritical fluids with CO2, to achieve an important selectivity on the added value products obtained, said process being carried out at a temperature between 200ºC and 350ºC, and at a pressure between 160 bars and 600 bars, with periods of time between 25 and 90 minutes per cycle; transformation of the rest of the biomass after the previous extraction either by thermal liquefaction for biocrub or sale of the biomass for food purposes for animals or for fish feeding. 2. Procedure for obtaining biomass and derived products from unicellular algae, according to claim 1, characterized in that the product of each of the returns obtained in the previous phases is stored in a previous unit with treatment by agitation, aeration, contribution of compressed air and CO2, as well as supply of nutrients and filtration and disinfection treatment, prior to its passage to the feed tank and replacement to the cultivation area, after each of the extractions. 3.-Procedure for obtaining biomass and derived products from unicellular algae, according to previous claims, characterized in that the current of CO2 gases entering each photobioreactor, comes from a combustion source or an accumulation tank of effect gases greenhouse, the surplus of CO2 being returned again to the corresponding photobioreactor, when the conditions for carrying out photosynthesis are not optimal. 4. Procedure for obtaining biomass and derived products of high added value from unicellular algae, according to previous claims, characterized in that the current of CO2 gases is injected in an amount comprised between 0.01 m3 per m3 of culture and 1 m per m 3 of culture, at intervals between 10 and 60 seconds per minute. 5.-Procedure for obtaining biomass and derived products from unicellular algae, according to previous claims, characterized in that the culture is introduced by the top of the photobioreactor, being collected from the bottom and mixing between each group of photobioreactors with the same electro pump, the culture conditions being the same for the whole group, achieving a perfect mixture of nutrients, cultures with different irradiations and therefore with different light passages, all with a recirculation flow between 1 and 50 % of total crop volume. 6.-Procedure for obtaining biomass and derived products from unicellular algae, according to previous claims, characterized in that the culture is maintained in the temperature range between 102C and 452C, achieving a tempering thereof through a primary circuit that runs through the inside the annular and concentric tubes that form each photobioreactor. 7.-Procedure for obtaining biomass and derived products from unicellular algae, according to previous claims, characterized in that each time the optimal microalgal concentration characteristic for each species is achieved, but, greater than 100 million cells / mi, it proceeds to the extraction of between 1 and 25% of the photobioreactor culture, in a period of between 1 and 4 hours. 8.-Procedure for obtaining biomass and derived products from unicellular algae, according to previous claims, characterized in that the same amount of culture extracted from photobioreactors is introduced, from feed tanks that in turn collects all rejections or leftovers from the different processes carried out in the crop until the final products are obtained, properly filtered and the organic load is eliminated and with a certain amount of fresh salt water also filtered and disinfected conveniently, the treated water being added with nutrients in adequate proportion, thus as of nitrogenous salts such as ammonium, nitrates, phosphates and other trace metals. 9.-Installation for the execution of the procedure of claims 1 to 8, which includes a system of separation of the biomass from the crop and the crop to a series of photobioreactors (19) in which the unicellular algae are introduced for cultivation, With injection of CO2, compressed air and appropriate nutrients, all in an aqueous medium with seawater or salt water, it is characterized in that each photobioreactor (19) is formed by two concentric tubes (20, 21), between which a chamber is established or hollow for cultivation (22), as well as for CO2 and compressed air, said photobioreactors being

(19)

tightly closed by an upper cover (24) and a lower base (25), with the particularity that each photobioreactor (19) is associated with a hydraulic system

(2. 3)

in addition to an inlet system (26) of C02) and an inlet system (27) of compressed air, incorporating in the upper part an automatic system of recovery of CO2 surplus or evacuation to the oxygen atmosphere, presenting such a system of superior recovery a degasser or outlet tube (29) with a sensor (30) and a three-way solenoid valve (28), through which the recovery of CO2 is achieved for its application back to the input system (26) by means of a pipe and compression system if necessary (31 -33) or for the evacuation of oxygen to the atmosphere (32), as appropriate, all this to ensure a performance in the CO2 fixation of the

95% 10.-Installation, according to claim 9, characterized in that it includes an internal culture tempering system, based on a recirculation circuit (36) which, in combination with electric pumps, geothermal heat pumps (35) or the like, solenoid valves, valves and complementary elements, constitute a primary tempering circuit with energy exchange without interchange intervention, in which the crop (22) recirculates between different photobioreactors to homogenize their properties between them. 11.-Installation, according to claim 9, characterized in that it includes an internal automatic cleaning system, formed by plastic pipes (37) provided with multiple and small holes (38) for the exit of a cleaning agent (39) that affects the inner face of the inner (20) and outer (21) tubes that form each photobioreactor (19), producing cleaning of that inner face of said tubes (20, 21) in contact with the crop.