PRE-TREATMENT PROCESS FOR HYDROCARBON-BASED LIQUID FUELS AND HYDROCARBON-BASED FUELS

The present invention refers, in one aspect, to a pre-treatment process for hydrocarbon-based liquid fuels, providing less pollutant and more efficient use in internal combustion motors, in comparison with the same fuel when non-treated.

In another aspect, the invention refers to fuels obtained by means of the new process.

Fuels as mentioned herein are particularly the ones used in explosion engines and diesel engines.

It is also understood, as used herein, that "pre-treatment" refers to a treatment given to a fuel usually available in the market, before being used for burning in a vehicle.

In the following text, although diesel is frequently mentioned, it occurs just to facilitate the understanding of the invention, which applies to any hydrocarbon-based fuel, therefore there are no limitations other than the ones expressed in the attached claims.

BACKGROUND OF THE INVENTION

The pollutants contained in the exhaustion gases from internal combustion motors constitute a negative aspect for public health.

A growing number of studies shows the prejudicial effect of automotive pollution over public health, justifying the fact that many pollutants emitted by motors using fossil origin fuels are the object of regulation in most parts of the world, such as: carbon monoxide, unburnt hydrocarbons, nitrogen oxides, sulfur dioxide, particulate matter, metals.

When the atmospheric concentration of such pollutants increases, they deteriorate breathing and cardiovascular conditions, and may cause irritation to the eyes and headache. Hospitalization of affected people and

associated medical costs represent an important financial cost. Furthermore, the automotive pollution contributes to the greenhouse effect and other deleterious effects over ecology (animals, plants, agriculture), architecture, tourism, etc. On the other hand, technology aims to make the burning of hydrocarbon-based fuels more and more efficient and less polluting. Full burning is aimed at, as well as the reduction of the corrosive effect on the engines, typically caused by the presence of water contained in fuel and aggressive chemical compounds originated from incomplete combustion. Whatever the effects currently caused by hydrocarbon-based fuels, various proposed solutions for that are found in the state of the art.

One frequent example is the use of additives directly added to the fuel within the vehicle itself. The above mentioned documents are representative of that: - U. S. Patent n ⁰ 4,424,063 published in 1984, additive to increase the flashing point;

U. S. Patent n ⁰ 4,451 ,266 published in 1984, additive to obtain more efficient and cleaner burning;

U. S. Patent n ⁰ 5,505,867 published in 1986, additive to improve combustion;

U. S. Patent n ⁰ 6,419,715 published in 2002, additive to reduce pollutant emission.

Another frequent example is the use of catalysts to filter the emission of nitrogen oxides and particulate matter from the vehicle exhaust. One verifies that such solutions do not attack the cause of the problems, i.e. the quality of the fuel to be burned.

In this sense, there are proposed solutions such as the mixture of various fuels for burning in explosion or diesel engines, one example of which is

the patent US 4,405,337, disclosing a mixture of alcohol, gasoil and castor oil.

There are also proposals for the pre-treatment of fuels so as to minimize problems before they are burnt. One example is the patent US 5,942,127, proposing a process to heat fuel to volatilize part of the contaminants, followed by filtering while still hot, with catalytic and mechanical steps, so as to remove non-volatile contaminants. Another example is the European patent document EP 416,907, proposing a treatment to remove soot contacting the fuel substrate (e. g. alumina, active carbon, etc.) impregnated with strong alkali. The present invention is different from everything found in the prior art, since it aims the clarification of a hydrocarbon-based fuel in a simple and economic way, at room temperature, by removing water, particulate matter, sulfur derivatives and metals. The obtained fuel has a limpid aspect, is practically odorless and has substantially no sediments. Its combustion generates less nitrogen oxides and emits less sulfur derivatives. The engine using it is less subject to corrosion and its operation is more efficient.

The invention therefore refers to a pre-treatment process of hydrocarbon-based liquid fuels, characterized by comprising the following steps at room temperature (percentages by weight with relation to the weight of the fuel): a. addition to the fuel of 3% to 8% of a mixture of water and one or more fatty acids with 16 to 24 carbon atoms, and 5% to 15% of one or more strong alkalinizers; b. agitation to promote the formation of residues; c. removal of residues; d. addition 1 % to 4% of one ore more alkanols with three to six carbon atoms and at least two hydroxyls; e. agitation to promote the formation of residues; and

f. removal of residues.

In one particular embodiment, in step a, the mixture of water an fatty acid comprises about 50% water.

Advantageously, along step b of agitation, an intermediate step of rest is taken, with subsequent agitation.

It is appropriate to perform step b along four to eight hours. Particularly, step b comprises a first agitation period during 2/3 of the time (e. g. four hours), followed by a resting period from 10 to 30 minutes, and another agitation period during the remaining 1/3 of the time (e. g. two hours). Step c and step f of residue removal are performed by any means known to the person skilled in the art, e. g. by removing or depleting the decanted material after the mixture rests to obtain separation of the residues.

Adequately, step e of agitation takes one to four hours.

Between steps e and f, a period of rest is appropriate, e. g. for two to six hours, before residues are removed.

Not excluding any others, particular fatty acids are unsaturated or polyunsaturated, comprising one or more hydroxyls (therefore hydroxy- substituted), such as ricinoleic acid. Vegetable oils containing such acids are an appropriate source, such as castor oil, and may be directly used. Appropriate strong alkalinizers, not excluding any others, are barium oxide, calcium hydroxide, lithium hydroxide, potassium hydroxide, sodium hydroxide, magnesium hydroxide, zinc oxide, magnesium carbonate, sodium aluminate, sodium carbonate and their mixtures. Sodium hydroxide is particularly used, under the form of water-diluted caustic soda. Particularly, the alkanol is glycerol, preferably bi-distilled.

The clarified fuel has low contents of sulfur and water and higher flashing point than the initial untreated fuel.

An advantage of the fuel of the invention is that it may be stocked

for significantly longer periods than non-clarified fuels, with much less loss by evaporation, since its flashing point is higher. The fact it is practically exempt from water promotes more efficient combustion and less deterioration of pipes and equipment through which it circulates within the engines. In another aspect of the invention is the clarified fuel itself, obtained by means of the process disclosed further above.

EXAMPLE

An example of the invention is given below, representing just a particular embodiment, imposing no limitation other than what is included in the attached claims.

A batch of ordinary diesel fuel was purchased in the market. Said batch was submitted to pre-treatment according to the invention, with the following steps, at room temperature (percentages in weight with relation to the weight of diesel): in a mixer, 5% castor oil (50% in water) and 10% sodium hydroxide dissolved in water were added to the diesel and agitated for four hours; it was left to rest with no agitation for fifteen minutes; it was agitated for two further hours; - it was left to decant and the residue was removed from the bottom of the equipment;

2% bidistilled glycerol was added; it was agitated for two hours; the residue was removed from the bottom of the equipment. Both the commercial diesel and the clarified diesel were analyzed.

The results are presented on Table I below.

TABLE I COMPARISON BETWEEN THE PROPERTIES OF CLARIFIED DIESEL OF THE INVENTION

AND COMMERCIAL DIESEL (ESTIMATE UNCERTAINTY OF RESULTS SUPPLIES A

CONFIDENCE LEVEL OF 95%)

(1 ) ASTM D 4294-03 "Standard Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-Ray Fluorescence Spectrometry".

(2) ASTM D4737-03 "Calculated Cetane Index by Four Variable Equation".

(3) ASTM D 93-02a "Standard Test Method for Flash Point by Pensky-Martens Closed Cup Tester". (4) ASTM D 6371-99 "Standard Test Method for Cold Filter

Plugging Point of Diesel and Heating Fuels".

(5) ASTM D 524-03 "Test Method for Ramsbotton Carbon Residue of Petroleum Products".

(6) ASTM D86-04b "Standard Method for Distillation of Petroleum Products".

(7) ASTM D 4052-02 "Standard Test Method for Density and Relative Density of Liquids by Digital Density Meter".

(8) ASTM D 1796-02 - "Standard Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method (Laboratory Procedure)". As we can see from the improved qualities of the clarified fuel, after being submitted to the process of the invention, it becomes more efficient in burning and less pollutant than non-transformed fuel.

The teachings and the example presented herein allow a person skilled in the art to practice the invention in ways not exactly as disclosed, but in an equivalent form, with functions and results in the same order of magnitude, therefore within the scope of protection as limited by the attached claims.