PROCESS FOR THE PRODUCTION OF BIOLIQUID OR BIOFUEL

***

FIELD OF THE INVENTION

The present description concerns a process for the production of bioliquids or biofuels.

TECHNOLOGICAL BACKGROUND

Bioliquids are liquid fuels that find application in the production, for example, of electric power and heat, whereas biofuels are used in the transport sector .

Said biofuels are produced starting from a biomass, i.e., from the biodegradable fraction of products, waste, and residue of biological (vegetable and animal) origin prevalently coming from agriculture, silviculture, or industrial activities. By the term "biomass" is moreover meant the biodegradable portion of urban waste.

Vegetable oil, for example, is a liquid fuel obtained by means of pressing of and/or chemical extraction from seeds of oleaginous plants (for example, soybean, palm, sunflower) . In addition to being used in human alimentation, vegetable oil is used as bioliquid in static engines for energy production.

By subjecting vegetable oil to a process of trans- esterification a product is obtained, referred to as "biodiesel", which can be used, for example, for supplying engines in the transport sector. Trans- esterification is a chemical reaction the main result of which is the modification of the molecules of triglycerides by means of alcohol in the presence of a catalyst, with formation of a mono-alkyl ester (biodiesel) and crude glycerol.

The biodiesel thus produced mainly finds application as fuel in the transport sector and as fuel in the production of electric power and heat.

Bio-ethanol is a liquid biofuel deriving from fermentation of vegetable biomass with high sugar content (for example, cane, beet, sweet sorgho) and starch content (for example, maize, wheat, barley, rice) . Bio-ethanol can be used for producing electrical energy and heat and as component of petrols (in this case, it finds application in the transport sector) .

The increase of agricultural surfaces designed for cultivation of plants for the production of bioliquids/biofuels and hence not for alimentary purposes inevitably gives rise to controversies.

The solution frequently adopted is to import oil, with very high provisioning costs, from countries such as South America, India, South-East Asia and Africa, i.e., countries that base their economy on the primary sector .

However, also this solution is very debatable in so far as it presents the disadvantage of subtracting - for the production of bioliquid or biofuel considerable vegetable resources that could used for alimentation to enable survival of poorly nourished social classes of the local populations.

The identification of biomasses not coming from dedicated crops and crops of a non-alimentary type is hence of fundamental importance. For example, to overcome the aforesaid disadvantages, non-alimentary materials are used, such as lignocelluiose biomasses, also resulting from agro- industrial and forestry activities, for the production of bioliquids /biofuels (as described, for example, in the patent documents Nos . WO-A-2011/073781, WO-A- 2010/069516 and WO-A-2010/053681) .

However, the production of bioliquids /biofuels starting from lignocelluiose biomasses presents evident disadvantages such as the need to use complex and costly production processes and the fact of obtaining products with characteristics that render them difficult to use.

For example, oil obtained from lignocelluiose material subjected to pyrolysis (a process of thermochemical decomposition of organic materials) presents the disadvantage of possessing high acidity and viscosity, solid residue, and high water content and having a limited calorific value.

Industrial research and experimental development in this field have made it possible to identify in the microbial biomasses a valid alternative to biomasses of vegetable origin for the production of bioliquids or biofuels .

Among the advantages deriving from the use of microbial biomasses the following may be listed:

the production of said biomasses is very fast;

the area required for the production is extremely small as compared to the one necessary for producing biomasses of vegetable origin; microbial biomasses are available in any period of the year;

the techniques used for proliferation of micro-organisms, for example yeasts and fungi, are known , and the plants for production thereof are widespread throughout the territory.

Yeasts, and more in general fungi, represent a group of micro-organisms extremely interesting for the production of bioliquids or biofuels.

. Yeasts are, in fact, able to proliferate very rapidly and accumulate a large amount of lipids characterized by a chemical composition similar to that of vegetable oils.

The patent document No. WO-A-2011/051977 describes a process for producing biodiesel starting from a yeast of the genus Pichia. Specifically, the document describes a process of extraction of oil starting from a biomass constituted by said yeast by means of centrifuging, homogeni zation , and extraction with solvents. The oil thus obtained is then subjected to a process of trans-esterification to obtain biodiesel.

Said process is complex and economically disadvantageous in so far as it requires, for example, a plurality of plants - which are very costly necessary for conducting the various steps of the process itself.

The document No. WO-A-2008/134836 concerns the production of biofuels from microbial biomasses of yeasts and fungi by extraction of the oils contained in said micro-organisms . The production of the oily phase takes place by implementing the process referred to as "direct thermopressurized liquefaction". This extraction process envisages the use of solvents and catalysts and is conducted at a temperature of between 120°C and 400°C and at a pressure of between 1 MPa and 5 MPa.

^■ The process described herein also presents operating conditions that call for complex and costly plants. Moreover, the use of solvents and catalysts concurs in increasing the cost of production of the biofuel.

The British patent No. GB 06604 describes a process of "dry distillation" of residual yeasts ^' from breweries and distilleries to obtain a gas that following upon condensation - generates a liquid phase largely with a base of water, containing large amounts of ammonia and high-viscosity tar, a gaseous phase, and a solid phase basically constituted by charcoal.

The Japanese patent application No. JP-A-7 216362 describes a process to obtain a fertilizer (referred to as "vinegar") by subjecting to dry distillation organic materials having a C/N ratio of 50:1. Cited among the materials that contribute to the component containing nitrogen are yeasts and yeast extract. The process described in the Japanese document makes it possible to obtain - following upon condensation of the gaseous phase generated by the distillation step - the aforesaid aqueous-based fertilizer, a high-viscosity oily liquid, a gaseous component, and a solid phase basically constituted by charcoal.

"Dry distillation" consists in a batch process of thermochemical degradation of the material introduced into a container in the absence of air, which is completed over a few hours .

The gas produced exits from the container and is condensed, normally at room temperature, to obtain a liquid largely made up of water with low tar content, a solid phase (charcoal), and a gaseous phase.

"Dry distillation" is basically characterized by:

- long stay times of the material in the container, equal to or longer than one hour, with a slow thermal transient to reach the working temperatures, with consequent:

i) stagnation of the water vapour and of the gas within the container, favouring the production of water and carbonization of the "submerged" material;

ii) cracking of the molecules in the gaseous phase, and obtaining of a high amount of gaseous component at the expense of the liquid;

- obtaining of a high amount of solid component, mainly charcoal, due to the fact that the material is loaded in batch from into the container and to the consequent presence of amounts of material that are barely moved or not moved at all, thus limiting participation in the reaction of part of the submerged material, which, in fact, carbonizes;

- working temperatures of between 250°C and

500°C reached in a slow transient, which favour a slow evaporation of the material;

- formation of a tarry layer on the surface of the material in the container, which further limits participation in the reaction, increasing the carbonization phase; - system with high thermal inertia and conseguent energy consumption such as to reguire always external energy sources to reach the working temperatures and to maintain them.

The products of dry distillation are basically constituted by charcoal, on average 35-55% of the initial mass, gas, approximately 20-35%, and an oily liguid phase, at . the most 15-25%, containing a relatively high percentage of water generally egual to or higher than 15-20%.

The oily liguid phase - to be used possibly for energy purposes as bioliguid or biofuel - must be separated from the water and subseguently refined to obtain a fraction lower than or equal to a few percent of bioliquid or biofuel with respect to the initial mass .

For the production of bioliquids/biofuels said process cannot consequently be used since it is anti- economic and polluting, and energy-intensive, whereas it can be advantageously applied for producing charcoal, even though the purification of water remains a critical aspect.

SUMMARY OF THE INVENTION

Considering the above premises, there is hence felt the need for improved solutions that will be more effective and enable production of bioliquids or biofuels in process and economic conditions that are more advantageous than the solutions adopted up to now.

According to the invention, the aforesaid object is achieved thanks to the solution specifically recalled in the annexed claims, which form an integral part of the present description.

The present description concerns a process for producing a bioliquid or biofuel that comprises the following operations:

i) providing a biomass of fungi, preferably yeasts ;

ii) subjecting said biomass to fast pyrolysis to obtain an oily liquid phase, a gaseous phase, and a solid phase; and iii) subjecting the oily liquid phase to at least one process of upgrading to obtain the bioliquid or biofuel..

The results provided in what follows show that the process described herein enables production of a bioliquid or biofuel with characteristics of lower acidity and viscosity and with clearly higher calorific value as compared to bioliquids or biofuels obtained from lignocellulose biomasses and from microbial biomasses subjected to the working processes known in the art.

Moreover, the process described enables bioliquids or biofuels to be obtained at costs considerably lower than those required for the production of bioliquids or biofuels obtained with the processes known in the art.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described in detail, by way of non-limiting example, with reference to the attached plate of drawings, wherein:

- Figure 1 is a schematic representation of an embodiment of the process for the production of bioliquids or biofuels forming the subject of the present description; and

Figure 2 is a schematic representation of a plant for implementing an embodiment of the process for the production of bioliquids or biofuels forming the subject of the present description.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The invention will now be described in detail, by way of non-limiting example, with reference to a process for the production of bioliquids /biofuels .

In the ensuing description, numerous specific details are presented for providing a complete understanding of the embodiments. The embodiments may be implemented in practice without one or more of the specific details, or with other processes, components, materials, etc. In other cases, well known structures, materials, or operations are not shown or described in detail so that certain aspects of the embodiments will not be obscured.

Throughout the present specification, the reference to "an embodiment" or "one embodiment" means that a particular configuration, structure, or characteristic described in relation to ^' the embodiment is included in at least one embodiment. Hence, the presence of phrases such as "in an embodiment", "in one embodiment", or "in a certain embodiment", in various points throughout the present specification does not necessarily refer to one and the same embodiment. Moreover, the particular configurations, structures, or characteristics can be combined in any suitable way in one or more embodiments .

The headings provided herein are for convenience and do not interpret the purpose or meaning of the embodiments .

The present description concerns a process of production of a bioliquid or biofuel that comprises the following operations:

i) providing a biomass of fungi, preferably yeasts ;

ii) subjecting said biomass to fast pyrolysis to obtain an oily liquid phase, a gaseous phase, and a solid phase; and iii) subjecting the oily liquid phase to at least one process of upgrading to obtain the bioliquid or biofuel.

For the purposes of the present description the terms "bioliquid" and "biofuel" are considered synonymous, irrespective of the meaning attributed to said terms by the standards currently in force, whether national or foreign, regarding bioliquids and biofuels.

The biomass of yeasts/fungi is characterized by a high percentage of carbon (higher than 50 wt% of the biomass) and does not contain lignocellulose substances .

The present description shows that, thanks to said characteristics, the biomass of yeasts/fungi is an optimal material to be subjected to a process of fast pyrolysis for the production of bioliquids/biofuels .

Instead, lignocellulose materials subjected to fast pyrolysis determine the synthesis of an oil characterized by high viscosity and corrosiveness . Moreover, when used in static engines or for means of transport as fuel, the high viscosity and acidity of the oil obtained can cause both damage to the injection system and encrustations on internal parts of the engine .

The processes used for the growth of yeasts, and more generally of fungi, are commonly known and similar for different species.

The yeasts/fungi that can be used for the production of a ^· biomass to be subjected to fast pyrolysis according to the present description are yeasts preferably not for human use, for example yeasts for feeding animals for breeding, residual yeasts from systems for water and sewage purification, waste yeasts from the production of alcoholic beverages, ethanol, bear and for bread making, or again residual material following upon extraction of oil from yeasts for nutriceutical purposes.

The process described herein envisages subjecting to fast pyrolysis either biomasses of yeasts/fungi purposely produced (primary biomasses) or ones that are the residue and/or waste of production of biomasses of yeasts/fungi for the applications referred to above. The biomass to be subjected to pyrolysis must in any case possess a degree of humidity of less than 20 wt%, preferably between 5 and 10 wt%.

Yeasts/fungi commonly used for the aforesaid purposes and for the production of bioliquid or biofuel according to the present description are, for example, selected from among: Aspergillus (fisheri, fumigatus, nidulas) , Candida (utilis, guilhermondi , oleophila, lopotica) , Criptococcus terricolus , Cladosporium (fulvum, herbarum) , Eremothecium ashovi, Hansenula (saturnus, ciferrii) , Kluyveromyces fragilis, Lipomyces starkeyi , Phaffia rhodozyma, Rhodutorala (glutinis , gracilis) , Rhodosporidium toruloides , Saccharomyces cerevisiae , Saccharomyces carisbergengis, Saccharomyces rauxii, Saccharomycopsis lipolytica , Sporidiobolus microsporus , Sporobolymices ruberrimus , Sporidiobolus microspores, Yarrowia lipolytica.

Figure 1 shows a diagram of an embodiment of the process of production of bioliquids or biofuels according to the present description.

In a first embodiment recourse is had to a primary microbial biomass 3a, i.e., a purposely produced one. In order to render the process of growth of the microorganisms economically advantageous it is possible to use waste or low-cost materials of a lignocellulose type (e.g. wood, bran, rice husks, etc.), materials rich in starches and sugars, digested by alcoholic production, molasses (from sugar refineries), glycerol (from production of biodiesel), optionally added with technical salts useful for the growth of microorganisms .

The step of production of the biomass of yeasts and/or fungi ^' takes place within tanks provided for the growth of the micro-organisms, such as for example fermenters. Generally, the substrate produced with residual substances, as listed above, on which the micro-organisms multiply must be prepared, for example, by means of processes of shredding and acid hydrolisis. The yeasts/fungi within the fermenter are fed with nutrients that are prepared and stored in closed steel tanks, provided with controlled openings, normally subjected to a step of sterilization with a current of steam. The fermenters are provided with an aeration system to guarantee for the micro-organisms, cultivated with the appropriate nutrients, the oxygenation necessary for their growth and proliferation. The fermenters are provided with probes necessary for measuring the parameters required for growth of the micro-organisms, i.e., probes for detecting the temperature, pH, and dissolved oxygen. Moreover present is a system for monitoring the amount of yeast present in the tank.

By way of example, a factory for producing forage yeasts, supplied with 27,000 tonnes per year of bran, produce 19,000 tonnes per year of yeasts having the composition appearing below.

The average composition of said yeasts is summed up in the following list:

Appearance: powder - granules (but also pellets);

Colour: from light yellow to brown;

Odour: specific of the forage protein mixture;

Percentage of humidity: 5-10%;

Percentage of dry protein: 45-55%;

Percentage of ash: 6-10%;

Crude cellulose: 5-6%;

Living cells of autotrophic organisms: absent;

Toxicity: absent;

Calorific value: 2800 - 3500 kcal/kg.

It is evident from the above composition and from the high carbon content (on average in the region of 50%) that the yeasts constitute an optimal material for obtaining bioliquid/biofuel by means of the process of fast pyrolysis.

In a different embodiment, the microbial biomass

3b derives from residue and/or waste of production of biomasses of yeasts/fungi deriving from processes of water and/or sewage purification.

The use of a moist microbial biomass (such as the one coming from a fermenter 3a or the one deriving from processes of water and/or sewage purification 3b) envisages a step of dehydration and drying 5 of the wet biomass, i.e., passage thereof in a dessiccator operating, for example, thanks to the use of the heat produced by the fast-pyrolysis system or by a possible cogeneration unit fed with the gas produced by the fast-pyrolys is system.

In the case of a microbial biomass 3c, preferably a waste biomass, which has already been dried and/or contains a percentage of humidity not higher than 5- 10%, such as for example a microbial biomass deriving from the production of bread or bear, this can be directly fed to the fast-pyrolysis step 6.

In any case, also the microbial biomasses with low water content (10-20%) can be dried to 5% to guarantee a better effectiveness in the production of the oily liquid phase of the fast pyrolysis.

The biomass of yeasts/fungi to be subjected to the process of fast pyrolysis described herein moreover presents the advantage, as compared to lignocellulose biomasses, of not requiring further preparation steps, such as for example shredding.

Irrespective of its origin, the biomass of yeasts/fungi is subjected to the process of fast pyrolysis 6 within a metal reactor provided with walls constituted by materials (for example, ceramic and/or refractory materials) that enable the process to be conducted at high temperatures and in an acid environment .

The step of fast pyrolysis 6 is carried out in the complete absence of oxygen or else in the presence a (technically obtainable) minimum amount of oxygen such as to prevent combustion and gasification of said biomass .

The temperature at which the process of fast pyrolysis is conducted is comprised between 400°C and 800°C, preferably approximately 450-600°C according to the type of micro-organisms treated.

The step of fast pyrolysis 6 intrinsically comprises as a whole the following operations:

- fast evaporation of the biomass within the pyrolysis reactor to obtain a gas-vapour phase and a solid phase;

extraction from the pyrolysis reactor of the solid phase, basically constituted by char;

- fast extraction from the pyrolysis reactor of the gas-vapour phase, preferably by means of suction; and

- condensation of the gas-vapour phase extracted to obtain an oily liguid phase and a gaseous phase.

The process of fast pyrolysis is characterized by: continuous supply of the biomass to be subjected to pyrolysis in amounts such as to guarantee maximization of the production of oil;

minimal stay time of the material in the reactor, generally less than 30 s, preferably in the region of 10 - 15 s;

fast heating of the biomass at the maximum temperature: the biomass is, in fact, fed into the reactor when this is at the operating temperature;

evaporation of the biomass to obtain a gas- vapour phase and a solid phase in less than 5 s, preferably less than 2 s, more preferably in the region of 0.5-1 s;

extraction from the reactor of the gas-vapour phase in less than 5 s, preferably in the region 1-5 s, more preferably in the region of 1-2 s, to prevent the high temperatures within the reactor from causing cracking of the molecules of the gas-vapour phase to obtain a high amount of gaseous phase;

immediate condensation in less than 5 s, preferably less than 0.5-2 s, of the gas-vapour phase produced to obtain an oily liguid phase and a gaseous phase; and

extraction from the reactor of the solid phase produced, basically constituted by char, in a time in the region of 1-2 minutes.

In said conditions the highest amount of oily liguid phase is produced as a result of the combined effect of temperature in the reactor, time of stay of the material in the reactor where fast pyrolysis takes place, rate of extraction and condensation and of the characteristics of the biomass subjected to fast pyrolysis (composition, size, and drying) .

The material introduced into the reactor "evaporates" immediately, in less than 5 s, preferably less than 2 s, more preferably in the region of 0.5- I s, separating within the reactor the gas-vapour part, which passes rapidly to the condensation step to form an oily liquid phase and a gaseous phase, from the solid phase basically constituted by char, which is eliminated from the reactor and collected in a purposely provided container. On the other hand, it is to be noted that ^' the solid phase also presents a low residual tar content.

The rate of output of the gas-vapour from the reactor (1-5 s) and the condensation rate (0.5-2 s) prevent cracking of the molecules of the gas-vapour and enable maximum production of oily liquid phase.

The process of fast pyrolysis is triggered by propane gas or in any case with an external energy source. Then, the process is self-supplied exploiting the charcoal or the gas produced by the process of pyrolysis itself, directly by means of combustion or indirectly by using gas to produce the electrical energy necessary to supply electrical apparatuses for heating (for example, induction ovens or electrical hot plates) and for moving the service apparatuses such as augers, pumps, etc.

The gas produced by the process of pyrolysis and used for maintaining the temperature of the reactor at the desired level is normally made up of: CO (33-37%), H ₂ (33-37%), CH ₄ (28-32%), C0 ₂ (0.5-1%), N ₂ (5-7%) .

The fast pyrolysis can be obtained with various types of reactor, but always respects the functional principles described above.

Figure 2 is a schematic illustration of a plant for implementing the process according to the present invention.

The reactor 60 is fed with a biomass of yeasts/fungi 3a, 3b, 3c, having for example the composition described above for forage yeasts (50 kg of yeasts Saccha ro yces cerevisiae characterized by 5% humidity, 50% proteins, and 6% ash) .

The biomass is fed into the reactor by means of a hopper-auger 61 feed system so as to prevent any introduction of air.

The system is continuous, i.e., the speed of the auger is correlated to the amount of biomass being fed to the reactor.

The hopper-auger feed system 61 is provided with a sensor for detecting the too-empty condition (not illustrated), i.e., a sensor able to detect when the biomass supplied to the reactor 60 has run out and issue a warning in order to prevent entry of air into the reactor itself.

The reactor 60 is constituted by a cylinder, the temperature of which is brought to 600°C by means of gas, for example propane, which is oxidized in a jacket external to the reactor (not illustrated) . Once the desired temperature has been reached, the movement of the hopper-auger feed system 61 starts .

The biomass of yeasts (characterized by a fine size and with 5% humidity) immediately passes into the gas-vapour phase (leaving within the reactor 60 a solid phase) and flows into a condensation system 64 where it is immediately cooled (in about 0.5-2 s) for example by means of cooled water (at a temperature of approximately 10°C) .

If the liquid obtained has an acid value higher than 10-14 mg KOH/g, ammonium carbonate or bicarbonate are added to the yeasts being fed in amounts of 1- 5 wt% .

Set downstream of the condensation system 64 is an aspirator 66 for regulating the speed of outlet of the gas-vapour from the reactor and for maintaining the system in slight negative pressure.

The system 64 for condensation of the gas-vapour generated by fast pyrolysis of the biomass determines formation of an oily liquid phase and a gaseous phase.

The gaseous phase passes into a system for cleaning from any possible presence of charcoal dust 65

(deriving from the '-solid phase), and is subsequently sent on in part into an Otto-cycle generator 11 for the production of electrical energy and heat and in part to feed the reactor 60 itself (approximately 20-30% of the production of gas) .

The oily liquid phase obtained at the end of fast pyrolysis can be - if necessary - subjected to a step of separation 8 from the residual process water. In the various tests conducted by the present applicant with the yeasts described said step did not prove necessary, since an oily liquid phase with low water content was generated .

The oily liquid phase, possibly freed from the excess water, is subjected to one or more upgrading processes 9 for eliminating any possible solid residue (charcoal dust) for example by filtration or centrifuging, for improving the pH, for deoxygenation, for increasing the calorific value and reducing the viscosity to obtain at the end of said process or processes of physical upgrading the bioliquid or biofuel .

Said upgrading processes 9 can be selected from among: treatment with natural mineral products such as zeolites, filtration-nanofiltration, passage in a cavitation reactor to obtain a molecular simplification (also referred to as "cold cracking"), deoxidation of the material, stable mixing with water by means of cavitation .

The solid phase, referred to as "char", pushed along the reactor 60 by a wormscrew or auger 69, is expelled from the reactor and collected in purposely provided containers 63 by means of a delivery auger 68. The aforesaid solid phase can be used as agricultural amender or else can be further subjected to a treatment step 7 (with known technology, for example with vapour) to obtain active charcoal employing known technology.

Appearing in Table 1 is the content, expressed in weight percentage, of end products obtained at the end of the process of fast pyrolysis described above and conducted at temperatures of 600°C and 850°C.

Table 1

Product T = 600°C T = 850°C

Gaseous phase 10-20 wt% 63-70 wt %

Oily liquid phase 65-75 wt % 15-20 wt %

Solid phase (char) 15 wt % 15-17 wt % Product T = 600°C T = 850°C

Active charcoal 12 wt % 12 wt %

Table 1 shows that the products obtained from pyrolysis are both gaseous and solid (char and active charcoal), as well as liquid (oily liquid phase) in proportions that differ according to the temperature used .

The process of pyrolysis conducted at approximately 600°C, for the material treated, proves more effective in so far as it enables a greater amount of oily liquid phase, i.e., bioliquid/biofuel, to be obtained.

Appearing in Table 2 is the analysis of ^" the bioliquid produced with the fast pyrolysis using as biomass forage yeasts having the composition given above .

Table 2

PARAMETER UNIT VALUE

density kg/m ³ 898.7 hydrogen wt% 11.5 net calorific value MJ/kg 38 viscosity at 20°C mm ² /s 4.6 water % w/w 0.054 acid value mgKOH/g 11.3 phosphorus mg/ kg < 1 potassium mg/kg < 1 sodium mg/kg < 1 ash content % w/w 0.001

Fractional distillation simulated in gaschromatography fraction < 50°C (C6-C7) % v/v 0.92 fraction between 100 and 150°C (C8-C9) % v/v 5.54 PARAMETER UNIT VALUE fraction between 150 and 200°C (ClO-Cll) % v/v 23.22 fraction between 200 and 250°C (C12-C14) % v/v 13.02 fraction between 250 and 300°C (C15-C17) % v/v 12.27 fraction between 300 and 350°C (C18-C20) % v/v 8.89 fraction between 350 and 400°C (C21-C24) % v/v 8.39 fraction between 400 and 450°C (C25-C30) % v/v 6.07 fraction between 450 and 500°C (C31-C36) % v/v 2.62 fraction between 500 and 550°C (C37-C40) % v/v 1.09

The process described herein enables production of a bioliquid or biofuel with an acid value of 11 mg KOH/g, without any need for treatment with ammonium dioxide or other substances.

By implementing an upgrading step 9 by treatment with zeolites, an acid value of 0.4 mg KOH/g is obtained .

The calorific value of the bioliquid or biofuel is found to be of 38 MJ/kg; the one obtained on average is comprised between 32 and 40 MJ/kg and said value can be increased, according to the biomass used and the upgrading technique employed.

The bioliquid or biofuel obtained is characterized by a value of viscosity at 20°C of between 5 and 50 cSt, preferably approximately 20 cSt (datum variable according to the material used and the upgrading system adopted) .

In the example shown the value detected is 5 cSt at 20°C. The values of viscosity that can be achieved with the process described are decidedly lower than the values of viscosity of the bioliquids/biofuels obtained from lignocellulose biomasses .

From the fractional distillation simulated in gaschromatography , carried out on the biomass of forage yeasts, a light bioliquid was obtained: approximately 57% of the product had a number of carbon atoms of between 10 and 20 with boiling point of between 150°C and 350°C. The fractional distillation was obtained by bringing the sample of bioliquid up to temperature and extracting the fractions at the various temperatures. For example around 200°C we obtain petrol and around 350°C diesel oil.

The reduced viscosity of the bioliquid or biofuel obtained by means of the process described is determined both by the absence -of lignocellulose substances in the starting biomass and by the composition of the starting biomass, which is particularly suitable for pyrolysis (i.e., the yeasts), as well.. as by the use of the upgrading systems mentioned above, but above all by the use of fast pyrolysis .

The process described enables a bioliquid or biofuel to be obtained with characteristics that enable a particularly effective use thereof for supply of diesel engines, in particular for the production of electrical energy and of heat ( cogeneration ) .

The process of production of bioliquids or biofuels forming the subject of the present description presents numerous advantages as compared to the processes of production of bioliquids or biofuels described in the known art.

The process envisages the use of non-alimentary biomasses, the costs of production of which are mainly represented by the costs of the nutrients used for proliferation of the micro-organisms and by the degree of transformation into bioliquid/biofuel . The other addenda of the cost (for example, amortization costs, costs of management and of staff) on average account for about 22-28% of the total production cost.

An economically interesting alternative to the production of yeasts consists in the use of residual yeasts/fungi or ones coming from reclamation/purification activities .

Described in what follows, purely by way of non- limiting example, is a further embodiment of the process forming the subject of the present description.

A microbial biomass 3a of an oleic yeast, Rhodotorula Glutinis, was cultivated with the following nutrients :

molasses (previously steamed at 121°C for 20 minutes and filtered with active charcoal) ; technical-grade sodium nitrate; technical-grade magnesium sulphate.

The amount of daily nutrient was: 2.5 g/1 of molasses, 0.1 g/1 of sodium nitrate, and 0.1 g/1 of magnesium sulphate. The yeast thus fed produced lipids in an amount of around 30 wt%.

To assess the conditions of economic growth a parameter was defined, referred to as "Conversion Factor (CF)", which links the nutrients to the production of biomass; said value is linked with a simple mathematical algorithm to the cost of the nutrients, for each type of substrate. The CF is an experimental datum that depends also upon the physico- environmental and structural conditions of culture. Considering, then, an average generation encountered in the fast pyrolysis in bioliquid or biofuel of 50% of the weight of the biomass, the cost for production of biomass is given by the following formula

C _t = ((1000/(CF x Q _t )) ∑ Qi Ci ) (1/X)

i = l where :

Ci is the cost of the i-th nutrient (from 1 to n) (Euro/kg)

Qi is the amount of i-th nutrient (g/1) - Q _t is the total amount of nutrients (g/1)

P is the production of micro-organism/microorganisms (g/1 of dry material)

C _t is the cost of the nutrients in given conditions of growth to produce a tonne of oil (Euro/tonne)

X is the amount of oil produced in the pyrolysis plant (0.5 corresponds to 50%)

CF = P/Q _t

The cost of production of the microbial biomass is inversely proportional to the conversion factor CF and directly proportional to the cost of the individual nutrients, in proportion to the amount of each in the substrate.

With the conversion factor CF we have an immediate indication of the economicity of the culture in question .

For example, a conversion factor CF of 2 represents a conversion of one "quantity of nutrients" (for example, 2.7 g/1 per day) to obtain "two quantities" (approximately 5.4 g/1 per day) of dry biomass .

Continuing with the example, for a strain of Rhodotorula Glutinis fed with appropriately purified molasses (150 Euro/tonne - 2.5 g/1) and technical salts (0.8 Euro/kg - 0.2 g/1) we have a C _t of 198 Euro, but with a CF of 0.5 the C _t becomes 729 Euro, which represents a value that is not economically acceptable. In said conditions the process becomes economically advantageous in the case of molasses at 60 Euro/tonne and salts at 0.5 Euro/kg with a C _t of 370 Euro/tonne.

The data of CF encountered in the growth of Rhodotorula Glutinis are higher than 2 (from 2 to 5.9) . If we consider the other addenda at the maximum value (28%), and the CF at 2 with the maximum cost of the nutrients, we have a cost of the bioliquid or biofuel of 275 Euro/tonne, which is less than the costs of purchase of crude vegetable oil (500-800 Euro/tonne to which it is necessary to add the transformation costs) and than the cost of production of bio-ethanol (500- 500 Euro/tonne), thus demonstrating the economic validity of the process forming the subject of the present description.