EP0717097B1 - Fuel based on vegetable oil and an aromatic-rich fraction - Google Patents

Abstract

Fuel oil comprises 1-100 vol.% of a base compsn. comprising: (1) vegetable oil; and (2) petroleum cut rich in heavy fuel aromatics and derived from a non-hydrogenative process with the volume ratio of (1) to (2) of less than 2.

Description

The subject of the present invention is a fuel formed a composition based on natural vegetable oil, likely to be burnt in combustion, either directly or in mixture with one or several hydrocarbons.

To replace fossil fuel sources with of renewable energies, research is oriented for a few years towards the use of surpluses agricultural, to create new fuels or combustibles.

In addition, for a number of years already and more recently in 1992, due to policy reform agricultural sector, the C.E.E has set up a support system to oilseed producers, which promotes "fallow" energy "and the production of vegetable oils such as sunflower and rapeseed oil.

• de miscibilité : l'huile végétale, qui est un triester, se mélange difficilement avec des produits plus légers, de nature chimique différente ;
• de viscosité : la viscosité de l'huile végétale est de l'ordre de 70.10^-6m²/s (70 mm²/s) à 20°C, ce qui rend impossible son incorporation directe dans un produit tel que le fioul domestique (dit encore fuel oil domestique ou "F.O.D.") c'est à dire, en particulier, de viscosité inférieure à 7.10^-6m²/s (7 mm²/s) à 20°C, ou encore sa pulvérisation dans un brûleur classique pour FOD ;
• d'opérabilité et de stabilité au stockage (oxydation et pollution bactérienne) ;
• de mise en oeuvre, du fait des pertes de charge en lignes liées à la viscosité naturelle des huiles végétales ;
• d'encrassement de la chaudière, dû à une mauvaise combustion ;
• de brûleurs, car s'il existe sur le marché des brûleurs polycombustibles, ces brûleurs nécessitent un réchauffage du combustible, une adaptation de la ligne de transfert entre la cuve de stockage et le brûleur, voire une pulvérisation assistée, ce qui limite d'autant l'intérêt économique de brûler de l'huile végétale, s'il faut modifier des équipements qui utilisent actuellement du fuel oil domestique.

We know, however, that burning vegetable oil directly or incorporating high contents in a fuel, especially for boilers, is not without posing a whole series of problems:

• miscibility: vegetable oil, which is a triester, hardly mixes with lighter products, of different chemical nature;
• viscosity: the viscosity of vegetable oil is around 70.10 ^-6 m ² / s (70 mm ² / s) at 20 ° C, which makes it impossible to incorporate it directly into a product such as heating oil (also called domestic fuel oil or "FOD") that is to say, in particular, of viscosity less than 7.10 ^-6 m ² / s (7 mm ² / s) at 20 ° C, or its spraying in a burner classic for FOD;
• operability and storage stability (oxidation and bacterial pollution);
• of implementation, due to the pressure losses in lines linked to the natural viscosity of vegetable oils;
• fouling of the boiler, due to poor combustion;
• burners, because if there are multi-fuel burners on the market, these burners require heating of the fuel, an adaptation of the transfer line between the storage tank and the burner, or even an assisted spraying, which limits all the more the economic interest of burning vegetable oil, if it is necessary to modify equipment which currently uses domestic fuel oil.

This is the reason why we see the development of achievements targeting "green fuels", such as example of fuels including either minute quantities vegetable oil, generally less than 5% by weight, either derivatives thereof, in the form of ester rapeseed methyl in diesel. But the latter type of recovery of vegetable oils requires a step additional transesterification, then purification, which leads to a significant additional cost.

The Applicant has set itself the objective the direct recovery of vegetable oils, by their incorporation, as is and at high contents, in a fuel meeting the standards for using fuels domestic and therefore not requiring modifications to existing combustion plants.

During his work in the field of fuels the Applicant has established, in a manner surprising that a fuel with high contents natural vegetable oil - i.e. unprocessed - and an oil cut rich in aromatic compounds, in determined volume ratios, can be burned either directly, or mixed with other fuels of conventional type such as domestic fuel oil, which eliminates the problems mentioned above.

Refined vegetable oil may be present in the fuel according to the invention at such high contents only 50% by volume. Beyond such oil concentrations vegetable, it becomes necessary to change the burner (s) of the boiler.

The present invention therefore has for first object a fuel based on vegetable oil, characterized in what it contains between 100% and 1% by volume of a basic composition comprising at most 50% by volume of at least minus one vegetable oil and at least one petroleum cut rich in aromatic compounds such as heavy petrol, from a non-hydrogenating conversion, and in that the aromatic type vegetable oil / essence volume ratio is less than 2.

• d'une part, il peut renfermer jusqu'à 50% en volume d'huile végétale, sans besoin de modifier le(s) brûleur(s) de chaudière ;
• d'autre part, il est plus respectueux de l'environnement, car il incorpore de l'huile végétale, laquelle ne renferme pas de soufre et réduit donc l'émission de SO₂ dans les fumées ;
• enfin, il est compatible au stockage en présence des autres hydrocarbures de type fuel oil domestique ou équivalent.

The fuel according to the invention has various advantages:

• on the one hand, it can contain up to 50% by volume of vegetable oil, without the need to modify the boiler burner (s);
• on the other hand, it is more environmentally friendly, because it incorporates vegetable oil, which does not contain sulfur and therefore reduces the emission of SO ₂ in the fumes;
• finally, it is compatible with storage in the presence of other hydrocarbons of the domestic fuel oil type or equivalent.

Vegetable oil usable in fuel according to the invention is preferably an oil from a plant capable of be cultivated with a high yield per hectare. She can be chosen from the group comprising in particular sunflower oil, palm oil, coconut oil, soybean oil, rapeseed oil and mixtures thereof. Of preferably the vegetable oil is rapeseed oil.

Advantageously, vegetable oil is present in the fuel according to the invention at a rate of 10% to 50%, preferably 20% to 30% by volume.

The petroleum cut rich in aromatic compounds heavy petrol type from a conversion not hydrogenating, usable in fuel according to the invention can be chosen from the group comprising gasoline from catalytic reforming, gasoline from steam cracking, pyrolysis gasoline, gasoline from catalytic cracking or mixtures thereof. We will use preferably gasoline from catalytic cracking.

The petroleum fraction rich in aromatic compounds, which can be used in the fuel according to the invention, preferably has a distillation range of between 140 ° C and 240 ° C at atmospheric pressure. It preferably has a viscosity of a value between 1.1 and 1.5 10 ^-6 m ² s ^-1 at 20 ° C.

It advantageously comprises at least 25% in volume of aromatic compounds.

Advantageously, the basic composition contained in the fuel according to the invention comprises at least one cut petroleum with a distillation interval included substantially between 240 ° C and 380 ° C. Such a cut preferably consists of FOD or equivalent of light diesel type of catalytic cracking (or "LCO" in English).

According to a preferred aspect of the invention, the report volume between monoaromatic compounds and compounds diaromatics of the basic composition, which the fuel according to the invention, has a value chosen between 2 and 6.5, and is preferably on the order of 3.5. We measure this volume content of mono- and diaromatic compounds by the Fisher method, well known to those skilled in the art.

In the event that the petroleum cut rich in compounds aromatics comes from a hydrocarbon that has undergone non-hydrogenating conversion of catalytic cracking type, monoaromatic compounds and diaromatic compounds that she understands are present in a volume report with a value chosen, preferably between 8 and 12.

• 10% à 20% de paraffines,
• 5% à 20% d'oléfines,
• 0% à 5% de naphtènes,
• 25% à 80% d'aromatiques.

Such a cut from cracking preferably comprises, in% by volume,

• 10% to 20% paraffins,
• 5% to 20% olefins,
• 0% to 5% naphthenes,
• 25% to 80% aromatics.

The basic composition contained in the fuel according to the invention comprises 5 to 50% and, preferably, 20 to 40% by volume of aromatic essence.

• entre 5 et 50 % d'huile végétale,
• entre 5 et 50 % d'une coupe pétrolière riche en composés aromatiques provenant d'une conversion non hydrogénante, et
• le complément à 100 % d'un hydrocarbure de type fioul, dont 65 % en volume distille au-dessous de 250°C et 85 % en volume au-dessous de 350°C.

According to another aspect of the invention, the composition contained in the fuel according to the invention comprises, in% by volume,

• between 5 and 50% vegetable oil,
• between 5 and 50% of an oil cut rich in aromatic compounds originating from a non-hydrogenating conversion, and
• the complement to 100% of a fuel oil type, of which 65% by volume distills below 250 ° C and 85% by volume below 350 ° C.

According to a preferred variant, the hydrocarbon possibly present in the fuel according to the invention is a product meeting intersyndical specifications an oil of the domestic fuel oil type, hereinafter "FOD", or an equivalent.

• environ 30% d'huile de colza,
• environ 30% d'une coupe pétrolière, riche en composés aromatiques de craquage catalytique, et
• le complément à 100% de produit répondant aux spécifications intersyndicales d'un FOD ou d'un équivalent.

Also, the present invention also relates to a fuel comprising by volume,

• about 30% rapeseed oil,
• about 30% of an oil cut, rich in aromatic compounds of catalytic cracking, and
• the complement to 100% of product meeting the intersyndical specifications of a FOD or equivalent.

According to a variant also preferred, the composition that the fuel according to the invention contains up to 3 parts by volume of FOD or equivalent.

The invention finally relates to the use of fuel according to the invention in boilers and / or community and / or industrial type ovens.

The following examples illustrate the characteristics and advantages of the invention. They have no character limiting.

Examples

In the table below are listed various compositions referenced 1 to 7, containing rapeseed ("HC"), heavy gasoline from catalytic cracking ("ELCC") and heating oil ("FOD"). The contents are expressed in% by volume.

The rapeseed oil (HC) used here is a refined oil, marketed under the name LUBRIROB by the company ROBBE in Compiègne. Its pour point is less than -21 ° C and its viscosity at 20 ° C is 75.10 ^-6 m ² / s (75 mm ² / s).

The heavy catalytic cracking gasoline used here is a 140 ° C-203 ° C cut from a cracking unit catalytic comprising 65% aromatics, 12% olefins and 23% of saturated molecules.

• la viscosité, qui permet d'assurer la qualité au démarrage et au cours de la combustion (les injecteurs à pulvérisation mécanique présents sur les brûleurs classiques nécessitent une viscosité inférieure à 7,5.10^-6 m²/s) ;
• le point d'écoulement et le point de trouble, qui déterminent l'opérabilité à froid d'un combustible ;
• le point d'éclair, qui est relatif aux impératifs de securité d'utilisation d'un combustible. 1 2 3 4 5 6 7 Spécifications intersyndicales du FOD HC (% en volume) 30 30 30 40 5 5 10 ELCC (% en volume) 30 60 15 40 2,5 10 4 HC/ELCC 1 0,5 2 1 2 0,5 2,5 FOD (% en volume) 40 10 55 20 92,5 85 86 Viscosité à 20°C (mm²/sec) 7,1 <6 >9 7,4 6 5,5 >8 <7,5 Point d'écoulement (°C) -12 <-12 <-9 -18 <-9 <-9 <-9 <-9 Point d'éclair Luchaire (°C) 66 60 70 64 74 72 73 55<x<120 Point de trouble (°C) -8 <-8 <+2 <-10 <2 <2 <2 <+2

The following significant inter-union specifications of a FOD, for use on a fuel boiler in accordance with the invention, have been retained:

• viscosity, which ensures quality at start-up and during combustion (the mechanical spray injectors present on conventional burners require a viscosity of less than 7.5.10 ^-6 m ² / s);
• the pour point and the cloud point, which determine the cold operability of a fuel;
• the flash point, which relates to the safety requirements for using a fuel. 1 2 3 4 5 6 7 FOD inter-union specifications HC (% by volume) 30 30 30 40 5 5 10 ELCC (% by volume) 30 60 15 40 2.5 10 4 HC / ELCC 1 0.5 2 1 2 0.5 2.5 FOD (% by volume) 40 10 55 20 92.5 85 86 Viscosity at 20 ° C (mm ² / sec) 7.1 <6 > 9 7.4 6 5.5 > 8 <7.5 Pour point (° C) -12 <-12 <-9 -18 <-9 <-9 <-9 <-9 Luchaire flash point (° C) 66 60 70 64 74 72 73 55 <x <120 Cloud point (° C) -8 <-8 <+2 <-10 <2 <2 <2 <+2

We can see in this table that, for low contents in rapeseed oil in the basic composition (around 5 at 10%), the value of the HC / ELCC ratio should be slightly less than 2 to comply with specifications Deductions from the FOD.

However, as soon as the rapeseed oil content in the composition becomes significant (more than 20% by volume), this ratio is preferably chosen to be less than 1.

From the table above, we see that the fuel according to the invention comprising rapeseed oil perfectly meets intersyndical specifications retained for use on a FOD boiler, including cloud and flow points, as well as flash point, and constitutes a "green fuel" of substitution of conventional fuel from the state of the technical.

This "green fuel" can be burned in a boiler usually using domestic fuel oil, without modify the initial boiler installation, especially the burner (s) and it has a good storage stability. Finally, while it is well known to skilled in the art that burning rapeseed oil, even on a modified burner, poses a big problem of start-up (given the low intrinsic volatility of the product), adding ELCC mixed with quantities significant rapeseed oil significantly improves ignition by electrodes, when starting the burner.

Claims (15)

1. A vegetable oil based fuel, characterised in that it contains between 100 % and 1 % by volume of a base composition comprising

   at most 50 % by volume of a vegetable oil, and

   at least one petroleum fraction rich in aromatic compounds of naptha type, arising from a non-hydrogenating conversion,

      and in that the ratio by volume of vegetable oil/gasoline of aromatic type has a value lower than 2.
2. A fuel according to claim 1, characterised in that the vegetable oil is chosen from the group comprising sunflower oil, palm oil, copra oil, soya oil, rapeseed oil and mixtures thereof, and it is preferably rapeseed oil.
3. A fuel according to any one of the preceding claims, characterised in that the base composition comprises between 5 % and 50 %, preferably between 20 % and 30 % of vegetable oil.
4. A fuel according to any one of the preceding claims, characterised in that the petroleum fraction rich in aromatic compounds of naptha type is chosen from the group comprising the gasoline resulting from catalytic reforming, the gasoline from steam cracking, the gasoline from pyrolysis and is preferably the gasoline resulting from catalytic cracking, or a mixture of one or other of these gasolines.
5. A fuel according to any one of the preceding claims, characterised in that the petroleum fraction rich in aromatic compounds of naptha type has a distillation range of between 140°C and 240°C at atmospheric pressure.
6. A fuel according to any one of the preceding claims, characterised in that the petroleum fraction rich in aromatic compounds of naptha type has a viscosity of a value chosen between 1.1 and 1.5 10^-6m²s^-1 at 20°C.
7. A fuel according to any one of the preceding claims, characterised in that the petroleum fraction rich in aromatic compounds of naptha type comprises at least 25 % by volume of aromatic compounds
8. A fuel according to any one of the preceding claims, characterised in that the base composition comprises at least one petroleum fraction having a distillation range of substantially between 240°C and 380°C.
9. A fuel according to any one of claims 1 to 8, characterised in that the petroleum fraction rich in aromatic compounds of naptha type originating from catalytic cracking comprises monoaromatic compounds and diaromatic compounds present in a ratio by volume of a value chosen preferably between 8 and 12.
10. A fuel according to claim 9, characterised in that the petroleum fraction rich in aromatic compounds of naptha type originating from catalytic cracking comprises, in % by volume,

    10 % to 20 % of paraffins,

    5 % to 20 % of olefins,

    0 % to 5 % of naphthenes, and

    15 % to 80 % of aromatic compounds.
11. A fuel according to any one of the preceding claims, characterised in that the base composition comprises, in % by volume,

    between 5 and 50 % of vegetable oil,

    between 5 and 50 % of a petroleum fraction rich in aromatic compounds of naptha type originating from a non-hydrogenating conversion, and

    the remainder to 100 % of a hydrocarbon of domestic fuel oil type or an equivalent.
12. A fuel according to claim 11, characterised in that the hydrocarbon of domestic fuel oil type distils at 65 % by volume below 250°C and at 85 % by volume below 350°C.
13. A fuel according to any one of the preceding claims, characterised in that the ratio by volume between the monoaromatic compounds and the diaromatic compounds of the base composition which it contains has a value chosen between 2 and 6.5, preferably between 3 and 4.
14. A fuel comprising, in % by volume,

    approximately 30 % of rapeseed oil,

    approximately 30 % of catalytically cracked aromatic gasoline, and

    approximately 40 % of a product meeting the interunion specifications of a domestic fuel oil or an equivalent.
15. Use in a boiler running on domestic fuel oil of a fuel according to any one of the preceding claims, without modification to this boiler.