EP0717097A1 - On vegetal oils and aromatic fraction based fuel - 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 from a composition based on natural vegetable oil, capable of being burnt in combustion plants, either directly or as a mixture with one or more hydrocarbons.

In order to replace fossil energy sources with renewable energies, research has been directed for a few years towards the use of agricultural surpluses, to create new fuels or combustibles.

In addition, for a number of years already and more recently in 1992, as a result of the reform of the common agricultural policy, the EEC has set up a system of aid for oilseed producers, which favors "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 even spraying it 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 improper combustion;
• burners, because if there are multi-fuel burners on the market, these burners require heating of the fuel, adaptation of the transfer line between the storage tank and the burner, or even assisted spraying, which limits 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 projects targeting "green fuels", such as fuels comprising either minute quantities of vegetable oil, generally less than 5% by weight, or derivatives thereof. , in the form of rapeseed methyl ester in diesel. However, this latter type of recovery of vegetable oils requires an additional step of transesterification, then of purification, which entails a significant additional cost.

The Applicant has, for its part, set itself the objective of direct recovery of vegetable oils, by their incorporation, in the state and at high contents, in a fuel meeting the standards of use of domestic fuels and not requiring therefore, no modifications to existing combustion plants.

During its work in the field of alternative fuels, the Applicant established, surprisingly, that a fuel comprising high contents of natural vegetable oil - that is to say unprocessed - and a petroleum cut rich in aromatic compounds, in determined volume ratios, can be burned either directly or in a mixture with other fuels of conventional type such as domestic fuel oil, which eliminates the problems mentioned above.

The refined vegetable oil can be present in the fuel according to the invention at contents as high as 50% by volume. Beyond such vegetable oil concentrations, 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 that it contains between 100% and 1% by volume of a basic composition comprising at least one vegetable oil and at least one cut. petroleum rich in aromatic compounds of the heavy petrol type, originating from a non-hydrogenating conversion, and in that the volume ratio of vegetable oil / petrol of the aromatic type 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.

The vegetable oil which can be used in the fuel according to the invention is preferably an oil from a plant which can be cultivated with a high yield per hectare. It can be chosen from the group comprising in particular sunflower oil, palm oil, coconut oil, soybean oil, rapeseed oil and their mixtures. Preferably, the vegetable oil is rapeseed oil.

Advantageously, the vegetable oil is present in the fuel according to the invention in an amount of 10% to 50%, preferably from 20% to 30% by volume.

The petroleum cut rich in aromatic compounds of the heavy gasoline type originating from a non-hydrogenating conversion, usable in the fuel according to the invention, can be chosen from the group comprising petrol obtained from catalytic reforming, petrol from steam cracking, gasoline from pyrolysis, gasoline from catalytic cracking or mixtures thereof. Preferably use the 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% by volume of aromatic compounds.

Advantageously, the basic composition which contains the fuel according to the invention comprises at least one petroleum fraction having a distillation range comprised substantially between 240 ° C and 380 ° C. Such an oil cut preferably consists of FOD or equivalent of the light gas oil type of catalytic cracking (or "LCO" in English).

According to a preferred aspect of the invention, the volume ratio between the monoaromatic compounds and the diaromatic compounds of the basic composition, which the fuel according to the invention contains, has a value chosen between 2 and 6.5, and is, preferably around 3.5. This volume content of mono- and diaromatic compounds is measured by the Fisher method, well known to those skilled in the art.

In the case where the petroleum fraction rich in aromatic compounds comes from a hydrocarbon having undergone a non-hydrogenating conversion of the catalytic cracking type, the monoaromatic compounds and the diaromatic compounds which it comprises are present in a volume ratio of a chosen value, 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 gasoline of aromatic type.

• 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 the intersyndical specifications of a fuel 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 which contains the fuel according to the invention comprises up to 3 volume parts of FOD or an equivalent.

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

The examples which follow illustrate the characteristics and advantages of the invention. They are not limiting.

Examples

In the table below are various compositions referenced 1 to 7, containing rapeseed oil ("HC"), heavy gasoline of 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 gasoline of catalytic cracking used here is a 140 ° C-203 ° C cut coming from a catalytic cracking unit comprising 65% of aromatics, 12% of 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.

Tableau 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.

Board 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

It can be seen from this table that, for low rapeseed oil contents in the base composition (of the order of 5 to 10%), the value of the HC / ELCC ratio must be slightly less than 2 in order to comply to the specifications retained from the FOD.

On the other hand, 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, it can be seen that the fuel according to the invention comprising rapeseed oil perfectly meets the inter-union specifications adopted for use on a FOD boiler, in particular cloud and flow points. , as well as flash point, and constitutes a "green fuel" substitute for the conventional fuel of the state of the art.

This "green fuel" can be burned in a boiler usually using domestic fuel oil, without modifying the initial boiler installation, in particular the burner (s) and it has good storage stability. Finally, while it is well known to those skilled in the art that the combustion of rapeseed oil, even on a modified burner, poses a major starting problem (given the low intrinsic volatility of the product), l addition of ELCC mixed with significant amounts of rapeseed oil considerably improves the ignition by electrodes, when starting the burner.

Claims (15)

Fuel based on vegetable oil, characterized in that it contains, between 100% and 1% by volume of a basic composition comprising - at least one vegetable oil, and - at least one petroleum cut rich in aromatic compounds of the heavy gasoline type, originating from a non-hydrogenating conversion, and in that the volume ratio vegetable oil / essence of aromatic type has a value less than 2. Fuel according to claim 1, characterized in that the vegetable oil is chosen from the group comprising sunflower oil, palm oil, coconut oil, soybean oil, rapeseed oil and mixtures thereof, and is preferably rapeseed oil. Fuel according to any one of the preceding claims, characterized in that the basic composition comprises between 5% and 50%, and preferably between 20% and 30% of vegetable oil. Fuel according to any one of the preceding claims, characterized in that the petroleum fraction rich in aromatic compounds of the heavy petrol type is chosen from the group comprising petrol obtained from catalytic reforming, petrol from steam cracking, petrol from pyrolysis and gasoline from catalytic cracking, and is preferably gasoline from catalytic cracking, or a mixture of one or the other of these gasolines. Fuel according to any one of the preceding claims, characterized in that the petroleum fraction rich in aromatic compounds of the heavy petrol type has a distillation range of between 140 ° C and 240 ° C at atmospheric pressure. Fuel according to any one of the preceding claims, characterized in that the petroleum fraction rich in aromatic compounds of the heavy petrol type has a viscosity of a value chosen between 1.1 and 1.5 10 ^-6 m ² s ^-1 to 20 ° C. Fuel according to any one of the preceding claims, characterized in that the petroleum fraction rich in aromatic compounds of the heavy petrol type comprises, by volume, at least 25% of aromatic compounds. Fuel according to any one of the preceding claims, characterized in that the basic composition comprises at least one petroleum fraction having a distillation range substantially between 240 ° C and 380 ° C. Fuel according to any one of Claims 1 to 8, characterized in that the petroleum fraction rich in aromatic compounds of the heavy petrol type originating from catalytic cracking comprises monoaromatic compounds and diaromatic compounds present in a volume ratio of a selected value of preferably between 8 and 12. Fuel according to Claim 9, characterized in that the petroleum fraction rich in aromatic compounds of the heavy petrol 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 - 25% to 80% aromatics. Fuel according to any one of the preceding claims, characterized in that the basic composition comprises, in% by volume, - between 5 and 50% vegetable oil, - between 5 and 50% of an oil cut rich in aromatics of the heavy gasoline type coming from a non-hydrogenating conversion, and - the complement to 100% of a hydrocarbon of the domestic fuel oil type or equivalent. Fuel according to claim 11, characterized in that the domestic fuel oil type distills at 65% by volume below 250 ° C and at 85% by volume below 350 ° C. Fuel according to any one of previous claims, characterized in that the volume ratio between the monoaromatic compounds and the diaromatic compounds of the basic composition which it contains has a value chosen between 2 and 6.5, preferably between 3 and 4. Fuel comprising, in% by volume, - around 30% rapeseed oil, - approximately 30% of aromatic gasoline from catalytic cracking, and - around 40% of product meeting the intersyndical specifications of a FOD or equivalent. Use in a boiler operating on domestic fuel oil of a fuel according to any one of the preceding claims, without modification of this boiler.