WO2008110688A2

WO2008110688A2 - Method for preparing a biofuel, biofuel thus prepared, and heat production system using such a biofuel

Info

Publication number: WO2008110688A2
Application number: PCT/FR2008/000116
Authority: WO
Inventors: Lionel Limousy; Alain FLEITOUR; Pierre Madoc; Jean Quentin; Magali Le Fellic
Original assignee: Biothermie
Priority date: 2007-01-31
Filing date: 2008-01-31
Publication date: 2008-09-18
Also published as: FR2911880A1; FR2911880B1; WO2008110688A3; EP2115103A2

Abstract

The invention relates to a method for preparing a biofuel from an emulsion of water in at least one oil, that comprises mixing a fatty material and water in the presence of a first group of ethanol-free, predominantly lipophilic surfactants, said surfactant compounds having a hydrophilic/lipophilic balance hlb between 12 and 15, and a second group of ethanol-free, predominantly hydrophilic surfactants, said surfactant compounds having a hydrophilic/lipophilic balance hlb lower than 6. The invention also relates to a biofuel, to equipment for preparing such a biofuel, and to a heat production system using such a biofuel.

Description

PROCESS FOR THE PREPARATION OF A BIOCOMBUSTIBLE BIOCOMBUSTIBLE

SO PREPARED, EQUIPMENT AND PRODUCTION SYSTEM OF

HEAT IMPLEMENTING SUCH BIOCOMBUSTIBLE

The present invention relates to the field of biofuels obtained from animal or vegetable fats. The process aims to transform animal or vegetable oils by-products of various agro-food processing into a fuel for local use minimizing transport.

There are acceptable solutions for burning raw animal oils:

• pyrolysis: the process does not apply to animal oils,

• anaerobic digestion: flotation greases can be added in small quantities melted in anaerobic digestion plants with a carbon deficiency,

• transesterification: transesterification is the reaction that makes it possible to obtain, from fats, whether of animal or vegetable origin, and from an alcohol, fatty acids with physicochemical properties close to the constituents of domestic fuel. This technique of fat transformation is well known and has been the subject of numerous studies in order to converting raw vegetable oils or used frying oils into an environmentally friendly fuel.

Another method known in the state of the art generally involves the preparation of an emulsion by operations consisting in using relatively high proportions of surfactants (surfactants in English). The known processes have several disadvantages: lack of stability of the emulsion, use of chemical agents requiring facilities classified "Seveso risk".

In particular, it is known the method described in French patent FR2875810, which has the disadvantage of a massive use (20%) of ethanol led Seveso classification of customer sites.

Other patents relate to continuous processes for preparing an emulsified fuel, that is to say an emulsified mixture of water and at least one organic compound for distribution as other liquid fuels type fuel or domestic fuel. In these fuels, the organic phase is a petroleum cut, a vegetable or animal oil, or any other fuel used in motorized vehicles and domestic boilers, and more generally for the supply of internal combustion engines and others, and for the power supply devices. Many researchers are focused on the processes of preparation of emulsified fuels, but quickly came up against their difficult implementation mainly related to the lack of stability of the emulsions obtained. The storage stability of these emulsions has been defined by the Directorate General of Hydrocarbons of the French Ministry of Industry. According to this administration, a water-in-oil emulsion, therefore a hydrocarbon emulsion, is considered to be storage stable when, maintained at ambient temperature of 10 to 20 ° C, for at least four months, no break in temperature is observed. the emulsion in two or more phases.

International Patent Application WO 01/36569 teaches that, in order to remedy the lack of stability of emulsions, DE 19 704 874, DD 216 863, US 5 445 656 and WO 95/33023 have proposed methods and devices in fuel emulsions that can be loaded onto land vehicles, in particular diesel-engined vehicles. The emulsions described are emulsions of often aqueous external phase, this emulsion can be subsequently reversed by subsequent dilution in a combustible organic phase, as in the patent DE 19 704 874. The emulsion described in the application WO 95/33023 contains less 20% water which constitutes the external phase of the emulsion. In the application WO 92/11927, it is a question of preparing a concentrated emulsion containing from 40 to 80% by volume of water, this process consisting in separately preparing a fuel / additive demulsifier mixture and a water / alcohol mixture, to be introduced. these two mixtures at two distinct locations in a circulation loop comprising a pump that fulfills the two emulsification functions and circulates the mixture in the loop. The emulsion thus obtained is recovered at another end on the loop. In the patent application WO95 / 27021, an emulsified fuel is claimed, which comprises 20 to 80% by volume of water, the latter constituting the external phase of the emulsion, 2 to 20% by volume of an alcohol, the complement consisting of hydrocarbons and at least one nonionic emulsifier additive. The hydrocarbons introduced into this emulsion are gasolines, kerosene, gas oils, synthetic fuel oils or vegetable or animal oil derivatives. The claimed process is a bulk emulsion preparation process, stable for at least three months, which comprises mixing a water / alcohol solution with a hydrocarbon liquid and a demulsifying additive.

French patent application FR98 / 15625 describes a process for the batch production of water-in-oil emulsions having the advantage, compared with oil-in-water emulsions, of improving combustion by vaporization. brutal droplets of water dispersed in the oil whose effect is to disperse the hydrocarbons in the combustion chamber.

These solutions have the disadvantage of a production requiring expensive equipment and complex to adjust.

The invention relates in its most general sense to a process for preparing a biofuel from a water emulsion in at least one oil which comprises mixing a liquid fat and water in the presence of a first group of predominantly lipophilic surfactants without ethanol, said surface-active compounds having a hydrophilic / lipophilic balance hlb of between 12 and 15 and a second group of predominantly hydrophilic surfactants without alcohol, and in particular without ethanol, said surfactant compounds having a hydrophilic / lipophilic balance hlb less than 6.

The process consists in creating a very fine emulsion of water in animal or vegetable oil. The emulsion is stabilized by a set of suitable surfactants whose cost is low, for the best thermal and environmental result. The biofuel thus prepared may be supplemented with a dye and optionally a disinfectant which will not be described in the context of this patent. During boiler injection, the presence of micro-droplets of water dispersed in the oil generates micro-explosions that promote rapid and complete combustion of the animal and / or plant oil sprayed in the flame (SAE 890449, SAE 920464, SAE 920198).

This process should make it possible to better burn animal and vegetable oils which have become substitutes for fuel oils, in particular in the animal by-products processing industry, which burns about 100,000 tonnes per year in France.

It can also be used to improve the environmental balance of HVB (raw vegetable oil) combustions that develop for agricultural uses such as drying corn or fodder. The invention consists in raising the temperature during the process to a level sufficient for the animal or vegetable oil and then the emulsion produced to have a kinematic viscosity which is less than or equal to that required for the fuel oil.

According to a preferred embodiment, the process comprises two dies, a first die consisting of preparing a mixture of a fat and a first group of predominantly lipophilic surfactants without ethanol, said surfactant compounds having a hydrophilic / lipophilic balance hlb between 12 and 15, a second die consisting of preparing a mixture of water and a second group of surfactants predominantly hydrophilic without ethanol, said surfactant compounds having a hydrophilic / lipophilic balance hlb less than 6, the two mixtures thus prepared being then emulsified.

The process according to this preferred method differs from the state of the art in that the action of the surfactant compounds occurs in two separate phases. The surfactant consists of two or more products each belonging to two major families: that of surfactants predominantly hydrophilic and those of surfactants predominantly lipophilic.

The mixtures are made progressively: one or more surfactant compound (s) predominantly hydrophilic is (are) mixed with water; likewise one or more lipophilic surfactant compound (s) is (are) mixed with the oil and finally the water-in-oil emulsion is produced. The method according to the invention has the advantage of requiring only a small amount of pure surfactants from one to two per thousand only for the cumulative weight of the surfactants, resulting in a moderate cost. The biofuel thus prepared has a remarkable stability, the emulsion remaining stable for more than four months when it is stored at a temperature of approximately 20 ^° C.

The biofuel obtained is suitable for all thermal uses for powers greater than 20kw of self-igniting thermal installations which translate by releases of moderate gaseous pollutants compared with the crude oil or with respect to fuel oils. Preferably:

The proportion of pure surfactant compounds is less than 2 liters per thousand liters,

The proportion of pure surfactant compounds is at most equal to 2 liters per thousand liters,

• the proportion of fat is between 850 and 970 liters per thousand liters. According to a preferred variant, the fat is a fat of animal or vegetable origin brought to a temperature making it possible to reach a viscosity less than or equal to that of the fuel oil.

The invention also relates to a biofuel characterized in that it comprises, for thousand liters, 850 to 970 liters of fat, at most 2 liters of two minimum compounds of pure surfactants without ethanol, some predominantly hydrophilic, and the others predominantly lipophilic, and the complement of water. The invention also relates to equipment for preparing a biofuel according to the method according to the invention characterized in that it comprises three mixers, the first being intended to receive a fat and a group of surfactants predominantly lipophilic and being equipped with heating means heated to a temperature which makes it possible to attain a viscosity less than or equal to that of the fuel oil, the second being intended to receive water and a group of surfactants predominantly hydrophilic, the third being intended to receive the contents of the other two mixers. The invention also relates to a system for producing heat and possibly electrical energy (co-generation), characterized in that it comprises, on the same site, equipment for preparing a biofuel according to the process that is the subject of the invention. invention comprising three mixers, the first being intended to receive a fat and a group of surfactants predominantly lipophilic and being equipped with heating means brought to a temperature to reach a viscosity less than or equal to that of the fuel oil, the second being intended to receive water and a group of hydrophilic surfactants, the third being intended to receive the contents of the two other mixers and preferably to produce the water-in-oil emulsion, said equipment being connected directly to a system without requiring intermediate storage means.

Preferably, the heat generating system according to the invention comprises means for measuring the flow rate between the biofuel preparation equipment and the combustion system. The invention will be described in more detail in the description which follows, referring to an example of non-limiting embodiment illustrated by the accompanying drawings in which:

- Figure 1 shows a schematic view of a device according to a first embodiment of the invention; - Figure 2 shows a schematic view of a device according to a second embodiment of the invention;

FIG. 3 represents the diagram of the process for preparing a biofuel according to the invention; and

FIG. 4 represents an embodiment diagram of an installation of the equipment according to the invention.

FIG. 4a shows a detail of the Clarinet - surfactant pump assembly of FIG. 4.

FIG. 1 represents a schematic view of a first embodiment of an equipment according to the invention. It comprises a tank (1) having an orifice (2) for introducing animal or vegetable oil and an orifice (3) allowing the release of the oil mixture and predominantly lipophilic surfactants. The tank (1) comprises a supply duct (4) for the circulation of a heating fluid for maintaining the tank at a temperature to achieve a viscosity less than or equal to that of the fuel oil. The tank (1) further comprises a mixer with straight blades assembled around an agitating rod driven by a motorized group (5). In a first step, the tank (1) is filled with animal or vegetable oil and an additive mixture whose proportion in the final emulsion is less than or equal to: 1% _O of a group of pure surfactants predominantly lipophilic.

In a second step, the mixture from the tank (1) is transferred through the orifice (3) to a static or dynamic mixer (7) in which a mixture of water and hydrophilic surfactant compounds also occurs. The respective proportions of the mixture leaving the mixer (7) are as follows:

85 to 97% of animal or vegetable oil,

from 1 to 2% _o of pure surfactant compounds, - addition of water: qs 100%.

The surfactant compounds are formed of two distinct groups, having one of the predominantly lipophilic properties, the other predominantly hydrophilic properties.

The surfactant compounds used are amphiphilic molecules. On the one hand, they have a hydrophobic pole (apolar or slightly polar part) capable of interaction only Van der Walls (LW), which is generally a hydrocarbon group of alkyl type (fatty chain), and which may optionally contain atoms. of halogen, oxygen, and on the other hand a hydrophilic pole (polar part which contains hetero atoms such as O, S, P or N which are in alcohol groups, thiols, ...) capable of developing Van der Walls (LW) interactions, Lewis acid-base (AB) interactions and possibly electrostatic interactions when an ionizable function is present. They are, for example, compounds whose structure has a polar head (sulphonate group) and a fatty tail (alkyl group).

The mixture prepared in the tank (1) is then extracted through the orifice (3) and mixed by a mixer (7) before being stored, in the example described, in a storage tank (8). ) maintained at a temperature which makes it possible to attain a viscosity less than or equal to that of the fuel oil. This storage tank (8) also comprises a mixer with straight blades (9) driven by a motor (10). FIG. 2 represents a second exemplary embodiment, corresponding to a solution implementing two separate dies, one for the oil, the other for the water.

The first die comprises a supply duct (H) for the arrival of animal or vegetable oil, a mixer (12) and a conduit (13) for supplying lipophilic surfactant compounds.

The second die comprises a water supply comprising a pump (14) and a hydrophilic surfactant compound feed pipe comprising a pump (16). A mixer (17) prepares the phase aqueous feed to a mixer (17). A valve (15) regulates the proportion of the aqueous phase with respect to the oil. The mixture is stored in a buffer tank (18) feeding a combustion system (19) via a pump (20) and a mixer (21) ensuring the homogenization of the emulsion. A return duct (22) allows the return of the excess biofuel into the buffer tank (18).

FIG. 3 represents a schematic view of the biofuel preparation process according to the invention.

The first die is intended for the incorporation of a group of predominantly lipophilic surfactants (30) into a molten animal or vegetable oil, maintained at a temperature of approximately 50 ^° C. The two constituents are mixed in a mixer (32). ).

The second die is for the preparation of a mixture of water (34) with a predominantly hydrophilic surfactant group (35) to prepare a concentrated solution (37). This concentrated solution (37) is then diluted with water (36) to prepare the aqueous phase (39). The two fatty and aqueous phases are mixed in a mixer (40) to prepare a biofuel (41) consisting of a stable emulsion.

With reference to FIG. 4, an example of an installation for producing an emulsion according to the invention comprises an arrival of the fats via a pipe (50). protected upstream by a manual valve (51). In this installation, the fat then passes through a solenoid valve (52) connected to a programmable controller (not shown), disposed in an electrical cabinet (53), and then a feed pump (54). Said pump feeds a flowmeter (55), which will control the flow rates of fat entering the main tank (56) of the installation. This tank with a useful volume of about 100 liters is equipped with the following elements: - an electric stirring motor (57) equipped with a motor-reducer to vary the speed of rotation of the axis of a agitator (58) as indicated by the programmable logic controller;

an electrical resistance system (59) making it possible to maintain the emulsion contained in the tank (56) at a temperature of approximately 5O ⁰ C;

- a low level probe (60a) and a high level probe (60b) connected to the controller for controlling the supply of the main tank (56) of fat as well as surfactants and water;

- a temperature sensor (61) measuring the temperature of the emulsion in the vessel (56), allowing the controller to regulate the temperature of the emulsion to a value close to 5O ⁰ C; - A drain of the emulsion (70) located at the bottom of the tank; and - An outlet pipe of the emulsion (71) at the bottom of the tank, so that the supply of the combustion system is in charge.

In connection with the tank, a clarinet (62) consists of a tube provided with three inlet ports: an orifice (63) connected to a flowmeter (not shown) which allows the arrival of water at the end clarinet, and orifices (64) and (65) providing the two groups of surfactants. Under these conditions, the water naturally expels the surfactants in the tank.

The two groups of surfactants are fed to the orifices (64) and (65) via two pumps (68) and (69).

In order to maintain the fat at the inlet temperature at the outlet of the installation, a tracer (73) constituted in the example by a heating wire is arranged all along its path in the installation. In addition, to ensure the quality of the fat entering the installation, a sampling system (72) is installed between the pump (54) and the flow meter (55).

The entire installation is controlled by a remote searchable programmable controller, which is triggered by order of a combustion system as described with reference to Figure 2 (referenced 19). At first, the automat ensures that the installation is at temperature.

If the low level probe (60a) is no longer immersed, it sends a signal to the controller that opens the solenoid valve (52) allowing the arrival of fat. It simultaneously actuates the pumps (54), (68), (69) and the flow meter for introducing all the constituents of said emulsion in fixed proportions. Upon introduction of the components, the controller controls the activation of the agitator (58) in a high rotation mode of about 1500 revolutions per minute, for a duration of about 1 minute.

As soon as the high level probe (60b) is immersed, the programmable controller controls the shutdown of the pumps (54), (68), (69) and the flow meter (67) and substantially reduces the rotation of the stirrer ( 58) at a speed of about 150 rpm.

In a similar manner to the description with reference to Figure 2, a return duct allows the return of the excess biofuel in the tank (56). When the combustion system and the plant are completely stopped, the manual valve (51) upstream of the installation having been closed, the programmable logic controller closes the solenoid valve (52), which allows the opening of the drain (70) allowing the complete emptying of the installation. The invention is not limited to the examples described and shown. It is for example possible to use a heating sheath as a tracer, a dynamic mixer to replace the static mixer consisting of the tank with its stirrer.

Claims

1 - Process for preparing a biofuel from an emulsion of water in at least one animal or vegetable oil which comprises mixing a fat and water in the presence of a first group of predominantly lipophilic surfactants liposoluble materials without ethanol, said surface-active compounds having a hydrophilic / lipophilic balance hlb between 12 and 15 and a second group of predominantly hydrophilic surfactants without ethanol, said surfactant compounds having a hydrophilic / lipophilic balance hlb of less than 6, said process comprising two dies, a first die consisting of preparing a mixture of a fat and a first group of predominantly lipophilic surfactants without ethanol, said surfactant compounds having a hydrophilic / lipophilic balance hlb between 12 and 15, a second die consisting of to prepare a mixture of water and a second group of hydro-dominated surfactants phile without ethanol, said surfactant compounds having a hydrophilic / lipophilic balance hlb less than 6, the two mixtures thus prepared being subsequently emulsified, the proportion of pure surfactant compounds is less than 2 liters per thousand. 2 - Process for the preparation of a biofuel according to any one of the preceding claims, characterized in that the proportion of fat is between 850 and 970 liters per thousand.

3 - Process for the preparation of a biofuel according to any one of the preceding claims, characterized in that the fat is a fat of animal origin and or heated vegetable heated to a temperature to achieve a lower viscosity or equal to that of fuel oil.

4 - Biofuel obtained by the process according to any one of the preceding claims, characterized in that it comprises, per thousand liters, 850 to 970 liters of fat, at most 2 liters of two groups of mixtures of pure surfactants without ethanol, one predominantly hydrophilic, and the other predominantly lipophilic, and the balance water.

5 - Equipment for preparing a biofuel according to the method of claim 1, characterized in that it comprises three mixers, the first being intended to receive a fat and a group of surfactants predominantly lipophilic and being equipped heating means, the second being intended to receive water and a group of hydrophilic surfactants, the third being intended to receive the contents of the other two mixers and to achieve the emulsion.

6 - heating system characterized in that it comprises, on the same site, equipment for preparing a biofuel according to the method according to claim 1 comprising three mixers, the first being intended to receive a fat and a group surfactants predominantly lipophilic and being equipped with heating means heated to a temperature to achieve a viscosity less than or equal to that of the fuel oil, the second being intended to receive water and a group of surfactants predominantly hydrophilic, the the third being intended to receive the contents of the two other mixers, said equipment being connected directly to a combustion system without intermediate storage means.

7 - System for producing heat and possibly electrical energy (co-generator) according to the preceding claim, characterized in that it comprises at least one means for measuring the flow rate between the biofuel preparation equipment and the system of combustion.