ITTO20111176A1 - PROCEDURE FOR THE PRODUCTION OF BIOLIQUIDS OR BIOFUELS - Google Patents

Description

â € œProcedure for the production of bioliquids or biofuelsâ €

TEXT OF THE DESCRIPTION

FIELD OF INVENTION

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

TECHNOLOGICAL BACKGROUND

Bioliquids are liquid fuels that are used in the production of, for example, electricity and heat, while biofuels are used in the transport sector.

These biofuels are produced starting from a biomass or from the biodegradable fraction of products, waste and residues of biological origin (plants and animals) coming mainly from agriculture, forestry and industrial activities. The term biomass also refers to the biodegradable portion of urban waste.

Vegetable oil, for example, is a liquid fuel obtained by squeezing and / or chemical extraction of oil plant seeds (for example soy, palm, sunflower). In addition to human nutrition, vegetable oil is used as a bioliquid in static engines for energy production.

By subjecting the vegetable oil to a transesterification process, a product is obtained, defined as biodiesel, which can be used, for example, to power engines in the transport sector. Transesterification is a chemical reaction whose main result is the modification of triglyceride molecules by alcohol in the presence of a catalyst, with the formation of a mono-alkyl ester (biodiesel) and crude glycerol.

The biodiesel produced in this way is mainly used as a fuel in transport and as a fuel in the production of electricity and heat.

Bioethanol is a liquid biofuel derived from the fermentation of vegetable biomass with a high sugar content (for example cane, beet, sweet sorghum) and starch (for example maize, wheat, barley, rice). Bioethanol can be used for the production of electricity and heat and as a component of gasoline (in this case it finds application in the transport sector).

The increase in agricultural areas destined to cultivate plants for the production of bioliquids / biofuels and therefore not for food purposes inevitably gives rise to controversies.

The solution often adopted is to import oil, with very high procurement costs, from countries such as South America, India, Southeast Asia and Africa or countries that base their economy on the primary sector.

However, this solution is also very questionable as it has the disadvantage of subtracting - for the production of bioliquid or biofuel - considerable plant resources that could be destined for the nutrition and survival of the less affluent social classes of local populations. .

The identification of biomasses not coming from dedicated and non-food crops is therefore of fundamental importance.

For example, to obviate the aforementioned disadvantages, non-food materials such as lignocellulosic biomass are used, also resulting from agro-industrial and forestry activities, for the production of bioliquids / biofuels (as described for example in the patent documents WO-A-2011/073781, WO-A-2010/069516 and WO-A-2010/053681).

However, the production of bioliquids / biofuels starting from lignocellulosic biomass has obvious disadvantages such as the need to use complex and expensive production processes and the production of products with characteristics that make them difficult to use.

For example, the oil obtained from lignocellulosic material subjected to pyrolysis (a thermochemical decomposition process of organic materials) has the disadvantage of having high acidity and viscosity, solid waste and high water content and of being endowed with a limited calorific value .

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

Yeasts, and more generally fungi, represent a group of microorganisms used for the production of bioliquids or biofuels.

The patent document WO-A-2011/051977 describes a process for the production of biodiesel starting from a yeast of the genus Pichia. Specifically, the document describes an oil extraction process starting from a biomass consisting of this yeast by centrifugation, homogenization and extraction with solvents. The oil thus obtained is subsequently subjected to a transesterification process to obtain biodiesel.

This procedure is complex and disadvantageous in economic terms as it requires a plurality of - very expensive - plants necessary to carry out the different phases of the procedure.

WO-A-2008/134836 concerns the production of biofuels from microbial biomasses of yeasts and fungi by extracting the oils contained in these microorganisms. The production of the oily phase takes place by implementing the process called â € œdirect thermopressurized liquefactionâ € (ELDT). This extraction process involves the use of solvents and catalysts and is carried out at a temperature between 120 and 400 ° C and at a pressure between 1 MPa and 5 MPa.

The process described therein also has operating conditions that require complex and expensive systems. Furthermore, the use of solvents and catalysts contributes to increasing the cost of biofuel production.

SUMMARY OF THE INVENTION

Taking these premises into consideration, the need is therefore felt for improved solutions, more effective that allow the production of bioliquids or biofuels in process and economic conditions that are more advantageous than what has been done so far.

In accordance with the invention, the above object is achieved thanks to the solution specifically referred to in the attached claims, which form an integral part of the present description.

The present description concerns a process for the production of a bioliquid or biofuel which includes the following operations:

i) providing a biomass of fungi, preferably yeasts (3a; 3b; 3c);

ii) subjecting the biomass (3a; 3b; 3c) to mechanical liquefaction (10) obtaining a solid phase and a first gas phase;

iii) subjecting the first gaseous phase to condensation (13) obtaining the bioliquid or biofuel and a second gaseous phase.

The results reported below show that the process described here allows to produce a bioliquid or biofuel with lower acidity and viscosity characteristics and with a much higher calorific value than the bioliquids or biofuels obtained from lignocellulosic biomass.

Furthermore, the described process allows to obtain bioliquids or biofuels at considerably reduced costs compared to 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 figure, in which:

- Figure 1: Schematic representation of an embodiment of the process for the production of bioliquids or biofuels object of the present description.

DETAILED DESCRIPTION OF SOME FORMS OF REALIZATION

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 following description, numerous specific details are presented to provide a complete understanding of the embodiments. The embodiments can be practiced 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 to avoid obscuring certain aspects of the embodiments.

Throughout this specification, reference to `` an embodiment '' or `` embodiment '' means that a particular configuration, structure, or feature described in connection with the embodiment is included in at least one embodiment . Thus, the appearance of the phrases â € œin one embodimentâ € or â € œin a certain embodimentâ € at various sites throughout this specification does not necessarily refer to the same embodiment. Furthermore, the particular configurations, structures, or features can be combined in any suitable way in one or more embodiments.

The headings presented here are for convenience only and do not interpret the purpose or meaning of the embodiments.

This description relates to a process for the production of a bioliquid or biofuel which includes the following operations:

iv) providing a biomass of fungi, preferably yeasts (3a; 3b; 3c);

v) subjecting said biomass (3a; 3b; 3c) to mechanical liquefaction (10) obtaining a solid phase and a first gas phase;

vi) subjecting said first gaseous phase to condensation (13) obtaining said bioliquid or biofuel and a second gaseous phase.

For the purposes of this description, the terms â € œbioliquidâ € and â € œbiofuelâ € are considered synonyms, regardless of the meanings attributed to these terms by current national and foreign regulations concerning bioliquids and biofuels.

The biomass of yeast / fungi is characterized by a high percentage of carbon (greater than 50% by weight of the same) and does not contain lignin.

The present description demonstrates that, thanks to these characteristics, the biomass of yeast / fungi is an optimal material to be subjected to a mechanical liquefaction process for the production of bioliquids / biofuels.

On the contrary, lignocellulosic materials subjected to mechanical liquefaction - in addition to requiring further processing operations of the lignocellulosic material before being subjected to mechanical liquefaction - determine the synthesis of an oil characterized by high viscosity and corrosivity. Furthermore, when used in static engines or for means of transport such as fuel, the high viscosity and acidity of the oil obtained can cause both damage to the injection system and encrustations to 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 mechanical liquefaction according to the present description are the yeasts used for example for the production of beer, ethanol, food supplements for animals, for bread making, for the purification of water and sewage, for the production of products that are used in the pharmaceutical and nutraceutical sector.

The process described here provides for mechanical liquefaction of both biomass of specially produced yeast / fungi (primary biomass) and residues and / or waste of biomass production of yeast / fungi for the applications indicated above. The biomass to be subjected to mechanical liquefaction must in any case have a degree of humidity lower than 15-20% by weight, preferably between 5 and 10% by weight.

Yeasts / fungi commonly used for the above purposes and for the production of bioliquid or biofuel according to the present description are, for example, selected from 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 toruloux caruloux, Saccisharomaccidioes, Saccisharomaccidioes, Saccisharvishar microsporus, Sporobolymices ruberrimus, Sporidiobolus microspores, Yarrowia lipolytica.

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

In a first embodiment the primary microbial biomass is specially produced 3a; the production phase of yeast and / or fungi biomass takes place inside tanks used for the growth of microorganisms, such as fermenters. The yeasts / mushrooms inside the fermenter are fed with nutrients that are prepared and stored in closed steel tanks, equipped with controlled openings, normally subjected to a sterilization phase with a current of steam. The fermenters are equipped with an aeration system to guarantee the microorganisms, grown with the appropriate nutrients, the oxygenation necessary for their growth and proliferation. The fermenters are equipped with probes necessary for measuring the parameters necessary for the growth of microorganisms, ie probes for detecting temperature, pH and dissolved oxygen. There is also a system for monitoring the quantity of yeast present in the tank.

In a different embodiment, the microbial biomass 3b derives from residues and / or waste of yeast / fungal biomass production deriving from water and / or sewage purification processes.

The use of humid microbial biomass (such as that coming from a fermenter 3a or that deriving from water and / or sewage purification processes 3b) involves a drying phase 5 of the wet biomass, i.e. the passage of the same in a dryer . The dryer can be powered for example by a cogeneration unit.

In the case of a 3c microbial biomass that has already been dried and / or contains a percentage of humidity not exceeding 15-20% by weight, preferably between 5-10%, such as for example a microbial biomass deriving from the production of bread or beer, this can be directly fed to the mechanical liquefaction stage 10.

The biomass of yeasts / fungi to be subjected to the mechanical liquefaction process described here also has the advantage, compared to the lignocellulosic biomass, of not requiring further preparation steps, such as shredding.

Regardless of its origin, the biomass of yeasts / fungi is subjected to a mechanical liquefaction process 10 in a metal reactor (for example of the auger type) equipped with one or more extruders or worm screws whose rotary movement determines a friction of the biomass on the extruders themselves and on the reactor walls with consequent generation of heat. The extruders or worm screws positioned inside the reactor are, for example, helical extruders, preferably but not exclusively two, cylindrical or conical, in counter rotation.

The biomass dragged by movement and by â € œfrictionâ € undergoes a phenomenon of molecule breaking, that is, when a certain temperature is reached, preferably between 300 and 350 ° C, the molecules constituting the biomass are reduced and pass into the gaseous phase.

The temperature and pressure of â € œfrictionâ € inside the reactor are regulated by the rotation speed of the extruders / worms and by the width of the free spaces existing between the extruders and the walls of the reactor itself.

In a preferred embodiment, it is possible to feed 11 (from an external source) hydrogen or a gas produced by water (by means of, for example, electrolytic cells or hadronic reactors or cold plasma systems) during the mechanical liquefaction phase. 10 to favor the hydrogenation reaction of biomass subjected to mechanical liquefaction so as to increase the achievement of a first high quality gaseous phase. In any case, it should be borne in mind that - even in the absence of hydrogen or gas 11 - during the mechanical liquefaction phase 10, the treatment of biomass by friction generates hydrogen itself.

The biomass of yeasts / fungi is introduced into the mechanical liquefaction reactor by means of a screw or pneumatic system, in order to avoid the entry of air. The mechanical liquefaction phase 10 is, in fact, carried out in the substantial absence of oxygen or in the presence of a reduced quantity of oxygen in order to avoid the combustion of the biomass.

The temperature at which the mechanical liquefaction step is carried out is between 200 ° C and 500 ° C, preferably about 350 ° C.

The reactor is initially heated by means of electric plates until it reaches the operating temperature; subsequently the temperature is kept constant thanks to the heat generated by the friction of the biomass on the extruders and on the walls of the reactor itself.

The process determines almost instantaneously the mechanical liquefaction (molecular decomposition) of the biomass of yeasts / fungi with obtaining a solid phase and a first gas phase.

The solid phase is subjected to an extraction operation 12 from the reaction environment, for example by means of an auger or filters, while the first gaseous phase is subjected to a condensation operation 13 to obtain a bioliquid or biofuel and a second gas phase.

The bioliquid or biofuel thus obtained is also preferably subjected to a separation step 8 from the residual process water.

The second gaseous phase obtained at the end of the condensation phase 13 is possibly used, for example, to feed 14 a cogeneration unit for the production of electricity and possibly heat necessary for the process (for example for the possible drying of the primary microbial biomass). The second gas phase obtained at the end of the mechanical liquefaction phase is normally composed of: CO: 33-37%, H2: 33-37%, CH4: 28-32%, CO2: 0.5â € “1%, N2 : 5â € “7%.

The bioliquid or biofuel (obtained at the end of the condensation phase 13) can optionally be subjected to one or more upgrade procedures 9 to eliminate any solid residues, improve the pH (if acidic), increase the calorific value and decrease the viscosity.

These upgrade procedures 9 can be selected from: treatment with natural mineral products such as zeolites in order to modify the pH, nanofiltration, passage in a cavitation reactor to obtain a molecular simplification (also called cold cracking), oxidation of the material, stable mixing with water by cavitation.

The solid residue, called charcoal, can be used as an agricultural soil improver or can be further treated, for example with steam, in a reactor 7 to obtain activated carbon with known technology, or else it can be pelletized.

Table 3 shows an example of the content, expressed as a percentage by weight, of the final products obtained at the end of the mechanical liquefaction process described above and carried out at final reactor temperature values of about 350 ° C, with revolutions ranging from 2500 and 6000. rpm, for a Saccharomyces cerevisae yeast having a composition of: proteins 50%, crude oils and fats 3%, crude cellulose 6%, ash 6%, humidity 8%.

Table 3

Final T reactor

Products

350 ° C

Second gas phase 40-50%

Bioliquid / biofuel 40-50%

Solid phase 5-10%

The procedure described here allows the production of a bioliquid or biofuel with pH which, in relation to the source material and to the regulation (extruder speed and temperature), is between 5 and 7.2.

The pH of the bioliquid or biofuel obtained can also be varied by using products such as zeolites, calcium carbonate or ammonium carbonate. Calcium carbonate or ammonium carbonate can be inserted directly into the mechanical liquefaction reactor.

The calorific value of the bioliquid or biofuel obtained is equal to 25-30 MJ / Kg and this value can be increased up to 30-40 MJ / Kg, depending on the material used and / or the upgrade technique used.

The bioliquid or biofuel obtained is characterized by a viscosity value at 25 ° C between 5 and 200 cSt, preferably equal to about 10-20 cSt (variable data depending on the material used and the upgrade system used), a value which is decidedly lower than that of bioliquids / biofuels obtained from lignocellulosic biomass.

The reduced viscosity of the bioliquid or biofuel obtained by the procedure described is determined both by the lack of lignin in the starting biomass, and by the composition of the starting biomass particularly suitable for the mechanical liquefaction operation (ie yeasts).

The described process allows to obtain a bioliquid or biofuel with characteristics that allow a particularly effective use for the powering of diesel engines, in particular for the production of electricity and heat (cogeneration).

The process for producing bioliquids or biofuels object of the present description has numerous advantages over the processes for producing bioliquids or biofuels described in the known art.

The process involves the use of non-food biomasses whose production costs are mainly represented by the costs of the nutrients used for the proliferation of microorganisms and the share of transformation into bioliquid / biofuel. The other cost addenda (for example depreciation, management and personnel costs) affect on average in the order of 22-28% of the total production cost.

The most economically viable alternative for the production of bioliquids / biofuels is the use of residual yeast / fungi or those deriving from reclamation / purification activities.

An example, purely by way of non-limiting example, of an embodiment of the process object of the present description will be provided below.

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

- Molasses (previously steamed at 121 ° C for 20 minutes and filtered with activated carbon);

- Technical grade sodium nitrate;

- Technical grade magnesium sulphate.

The daily amount of nutrient is 2.5 g / l of molasses, 0.1 g / l of sodium nitrate and 0.1 g / l of magnesium sulphate. The yeast fed in this way produced lipids in the order of 30% by weight.

To verify the conditions of economic growth, a parameter has been defined, called â € œConversion Factor - FDCâ €, which links nutrients to biomass production; this value is linked with a simple mathematical algorithm to the cost of nutrients, for each type of substrate. The FDC is an experimental datum that also depends on the physical-environmental and structural conditions of the crop.

Considering, then, an average generation found in the mechanical liquefaction in bioliquid or biofuel of 50% by weight of the biomass, the cost for the production of biomass is given by the following formula:

n

Ct = ((1000 / (FDC x Qt)) ∠'QiCi) (1 / X)

i = 1

where is it:

- Ci = cost in the i-th nutrient (from 1 to n) (euro / kg) - Qi = i-th nutrient quantity (gr / lt)

- Qt = total amount of nutrients (gr / lt)

- P = production of microorganism (s) (gr / lt of dry material)

- Ct = Nutrient cost under certain growth conditions to produce a ton of oil (euro / ton)

- X = share of oil production in mechanical liquefaction plant (0.5 corresponds to 50%)

- FDC = P / Qt.

The production cost of microbial biomass is inversely proportional to the FDC and directly proportional to the cost of the individual nutrients, in relation to the share of each in the substrate.

With the FDC you have an immediate indication of the economy of the crop in question.

For example, a FDC equal to 2 represents a conversion of a `` quantity of nutrients '' (for example 2.7 gr / lt day) to obtain `` two quantities '' (about 5.4 gr / lt day) of biomass dry.

Continuing in the example, for a strain of Rhodotorula Glutinis fed with suitably purified molasses (150 euro / ton - 2.5 gr / l) and technical salts (0.8 euro / kg - 0.2 gr / l) you have a Ctdi 198 euros, but with a FDC of 0.5 the Ctd becomes 729 euros, which represents an economically unacceptable value. Under these conditions, the process is economically advantageous again in the case of molasses at 60 euros / ton and Sali at 0.5 euros / kg with a Ct of 370 euros / ton.

The FDC data found in the growth of Rhodotorula Glutinis are higher than 2 (from 2 to 5.9), considering the other addends to the maximum (28%), and the FDC at 2 with the maximum nutrient costs, we have a cost of bioliquid or biofuel of 275 euros / ton, which is lower than the purchase costs of raw vegetable oil (500-800 euros / ton to which processing costs must be added) and the cost of producing bioethanol ( 500-500 euros / ton), demonstrating the economic validity of the process object of this description.

Below is an example of mechanical liquefaction fed with technical yeast, coming from the waste from the production of beer used for animal feed mentioned above (Saccharomyces cerevisae having an average composition of: proteins 50%, crude oils and fats 3%, crude cellulose 6%, ash 6%, humidity 8%).

The material is supplied in dry form with fine granulometry and consequently fed directly by screw to the mechanical liquefaction stage 10 inside the metal reactor.

The reactor, preheated to 300 ° C, contains 2 propeller extruders which are rotated at 5000 rpm.

At the end of the mechanical liquefaction phase, a solid phase and a gaseous phase are obtained, the latter subjected to a condensation operation to obtain a bioliquid or biofuel.

The final result consists of a bioliquid / biofuel in a quantity equal to 45% of the incoming biomass, a second gaseous phase equal to 47% and charcoal equal to 8%.

The bioliquid has the following physical properties:

- Density at 15 ° C: 0,87Kg / lt

- Lower calorific value: 40 MJ / KG

- Viscosity at 20 ° C: 4.6 Cst

- Water content: 0.06% m / m

- Number of acidities: 11 mg / KOH / g.

These properties allow the bioliquid / biofuel to be fed into low-rpm diesel engines for the production of electricity and heat.

In the case of the use of Rhodotorula Glutinis yeast with the production of bioliquid of 45% by weight, with a maximum FDC of 1.5 of the costs of the feed materials and with the sum of the additional costs equal to 28% of the total cost, obtains a cost of bioliquid equal to 408 euro / ton, which is convenient compared to other known methods, as well as giving a guarantee of continuous supply, without being an alternative to food.

Claims (12)

CLAIMS 1. Process for the production of a bioliquid or biofuel, said process comprising the following operations: i) providing a biomass of fungi, preferably yeasts (3a; 3b; 3c); ii) subjecting said biomass (3a; 3b; 3c) to mechanical liquefaction (10) obtaining a solid phase and a first gas phase; iii) subjecting said first gaseous phase to condensation (13) obtaining said bioliquid or biofuel and a second gaseous phase. 2. Process according to claim 1, wherein said biomass (3a; 3b) is subjected to a drying operation (5) before being subjected to mechanical liquefaction. 3. Process according to claim 1 or claim 2, wherein said biomass (3a; 3b; 3c) has a water content lower than 15-20% by weight, preferably between 5 and 10% by weight. 4. Process according to any one of the preceding claims, in which said mechanical liquefaction operation (10) is carried out at a temperature ranging from 200 to 500 ° C, preferably about 350 ° C. 5. Process according to any one of the preceding claims, in which said mechanical liquefaction operation (10) is carried out in the absence of oxygen, or in the presence of a reduced quantity of oxygen such as to avoid a combustion of said biomass. 6. Process according to any one of the preceding claims, in which said mechanical liquefaction operation (10) is carried out in the presence of hydrogen or water gas. 7. Process according to any one of the preceding claims, in which said bioliquid or biofuel is subjected to an extraction step (8) of the residual water. Process according to any one of the preceding claims, wherein said bioliquid or biofuel is subjected to an upgrade process (9). 9. Process according to claim 8, wherein said at least one upgrade process (9) is selected from: treatment with zeolites, nanofiltration, cavitation, oxidation, stable mixing with water. 10. Process according to any one of the preceding claims, wherein said bioliquid or biofuel has a pH between 5 and 7.2. 11. Process according to any one of the preceding claims, wherein said bioliquid or biofuel has a calorific value comprised between 30-40 MJ / Kg. 12. Process according to any one of the preceding claims, wherein said bioliquid or biofuel has a viscosity ranging from 5 to 200 cSt at 25 ° C, preferably about 20 cSt at 25 ° C.