FUEL OR CRUDE OIL ADDITIVE AND FUEL OR CRUDE OIL COMPOSITION COMPRISING SAID ADDITIVE

The present invention refers to a novel additive for improving the properties of fuel and/or crude oil compositions, said additive composition comprises at least one ferric or ferrous formate. In further aspects, the present invention refers to a fuel and/or crude oil composition comprising an active amount of said additive or an active amount of said ferric or ferrous formate and to the use of said additive or said ferric or ferrous formate in fuel and/or crude oil compositions, such as furnace or marine fuel oil compositions.

Heavy oils, such as heavy fuel oils (marine fuel oils) and mixtures of heavy fuel oils and heavy distillates (inter fuel oils) are used globally in large quantities, primarily as furnace fuels in industrial plants, power stations, gas turbines and also for internal combustion engines, such as marine engines and land based diesel units. Fuel oils are obtained in the refining of petroleum (crude oils), which essentially comprise of paraffinic, naphthenic and aromatic hydrocarbons some of which have high molecular weight, but also includes residual components from various distillation and thermal cracking processes. The high molecular weight components are typically termed asphaltenes often existing as insoluble aggregated particles randomly dispersed or in the process of sedimenting or flocculating, likewise other compounds having poor or insoluble characteristics (for example oxygen, nitrogen and sulphur compounds), likewise products resulting from aging (sludge), and likewise metallic porfyrins containing vanadium or nickel etc., all of which adversely affect the oil combustion process through intensified soot formation, deposits on metal surfaces of combustion units and plants, corrosion of metal components in combustion units and plants and also undesirable flue gas and stack emissions causing plume, acid rain and thus a negative impact on the environment.

Various metal additives, such as metal carboxylates, oxides and hydroxides to improve combustion in boilers, combustion engines and combustion turbines are known and/or have been suggested. These metal additives include species of iron, manganese, copper, alkaline earth metals, such as calcium and barium; cerium, platinum and palladium. Besides having a desired effect on the combustion, additives often have undesirable attributes, being themselves sources for atmospheric pollution, being corrosive or having deleterious effects upon the performance of the combustor itself.

Manganese, generally considered as an effective combustion additive and widely used as a combustion catalyst in boilers with residual oil comprising fuel contaminants, such as vanadium, forms low melting deposits and negates effects of magnesium on control of vanadium, sodium, calcium and potassium deposits. Iron is also regarded as an effective combustion additive while copper is regarded as less effective than either iron or manganese.

Calcium forms tenacious deposits with contaminant metals. Barium, a known smoke suppressant, forms toxic salts. Cerium is less effective because of its higher elemental weight.

Ferrocene, Fe(CsHs^, is probably the best known and most investigated organometallic additive. It is known to be a soot precursor in combustion and have been used for several years. A problem often encountered with Ferrocene is that it tends to leave an oxide deposit on the walls of the combustion chamber that can have severe degrading effects on its long-term performance.

hi the prior art there are numerous proposals that have already been made for additives which are intended to negate the disadvantages described. Thus FR 2 172 797 describes basic iron salts of organic acids and FR 2 632 966 describes a mixture of iron hydroxide and a basic calcium soap as auxiliaries to enhance the combustion of heavy fuel oils. US 4,129,589 recommends highly basic and oil-soluble magnesium salts of sulphonic acids as oil additives. EP 476 196 describes as oil additive, a mixture essentially comprising at least one oil-soluble carbonyl manganese compound and at least one oil-soluble neutral or basic alkali metal or alkaline earth metal salt of an organic acid component. GB 2 091 291 teaches diesel additives comprising calcium sulphonate, naphthenate, carbonate and/or oxide in combination with iron naphthenate, Ferrocene and/or iron oxide. SE 451 197 disclose the use of iron and/or manganese salts of aliphatic carboxylic acids having 3-10 carbon atoms as fuel additives. None of these disclosures teach, disclose or otherwise contemplate the use of iron formates as possible additive in fuel or crude oils and the fact that some disclosures are limited to metal salts of mineral and/or carboxylic acids having three or more carbon atoms negates and teaches away from the use of formates as effective additives in fuel and/or crude oils.

It has thus quite unexpectedly been found that individual or combinations of iron formates are particularly effective additives for fuel and/or crude oils with regard to improving combustion and the effects thereof. The present invention accordingly refers to a fuel or crude oil additive composition comprising at least one ferric and/or ferrous formate as sole organometallic component or in combination with for instance a calcium carboxylate. Said ferric and/or ferrous formate is suitably present in an amount of for instance between 0.5 and 99.5% by weight of said oil additive and in addition thereto at least one solvent, dispersant, stabiliser, anti-caking agent and/or other auxiliary agent per se known in the art.

Embodiments of said fuel or crude oil additive may additionally comprise at least one carboxylate, mineral salt, oxide or hydroxide of calcium, such as calcium formate and/or calcium sulphonate in a weight ratio Fe to Ca of for instance between 0.5 to 99.5 and 99.5 to 0.5% by weight calculated as metal, and/or at least one organic or inorganic metal compound, carboxylate, mineral salt, oxide and/or hydroxide, other than said ferric and/or ferrous formate and other than said calcium carboxylate or mineral salt, such as ferrous fumarate. These

preferred additional organic or inorganic compounds include species comprising iron, cerium, barium, beryllium, calcium, magnesium, copper, silver, zinc, cadmium, titanium, zirconium, molybdenum, chromium, tungsten, cobalt, nickel, lanthanum and/or ytterbium as active metal. Particularly preferred are carboxylates, mineral salts, oxides and hydroxides of barium, beryllium, calcium, magnesium, copper, zinc, zirconium, molybdenum, iron, nickel, cerium and ytterbium.

Further embodiments of said fuel or crude oil additive include fluid components comprising an active amount of at least one asphaltene dispersant and/or stabiliser in an amount of for instance between 0.1 and 50% by weight based on said metal compounds and/or fluid components comprising an active amount of at least one anionic, cationic and/or nonionic surfactant in an amount of 1-10%, such as 2-5%, by weight of said additive. Asphaltenes are colloidal dispersed components present in for instance crude oil and may precipitate due to changes in temperature, pressure, oil composition and/or when coming onto contact with other fluids and gases, sediment and sludge are formed in oil tanks and fuel lines. Additionally asphaltenes do not combust completely under normal conditions, resulting in loss of potential combustible energy and increase in unburned hydrocarbons in the fly ash. A typical and well known in the art solution to above problems is the use of an asphaltene inhibitor or more commonly an asphaltene dispersant/stabiliser. Suitable asphaltene dispersants/stabilisers can be exemplified by the Protea ^® RF-series supplied by System Separation, Sweden.

A fluid additive, including water based additives comprising one or more anionic, cationic and/or nonionic surfactants, according to the present invention is suitably prepared by mixing together the individual components according to specific requirements with or without the use of a solvent or dispersing medium, such as a hydrocarbon process solvent or oil and/or a glycol. Suitable solvents include rape seed methyl ester and other biodegradable solvents and suitable dispersants include tall oil fatty acid adducts. Preparation of said additive is suitably carried out at atmospheric pressure and at a temperature of for instance 15-100°C, such as 20-70°C.

Yet further embodiments of the fuel and/or crude oil additive of the present invention include dry powders or granules additionally comprising an active amount of at least one anti-caking agent, such as a magnesium and/or calcium salt of an oxidised microwax, a phenolic resin, a fatty acid derivative, an amide and/or an amide wax.

A powder form fuel and/or crude oil additive according to the present invention is preferably prepared by first milling included metal compound(s) to a particle size of preferably less than for instance 100 microns, using any suitable milling equipment. Although it is possible to pre-blend metal compound(s) and processing aid(s), such as an anti-caking agent selected from

the group consisting of for instance a magnesium and/or calcium salt of an oxidised microwax, a phenolic resin, a fatty acid derivative, an amide and/or an amide wax, to a desired composition, it is preferable to mill the components individually prior to blending.

Suitable embodiments of the additive of the present invention include for instance formulations having: i) Fe(E) and/or Fe(πT)formate as only active metal compound, ii) Fe(II) and/or Fe(IE)formate and Ca-carboxylate or mineral salt, such as Ca-formate or Ca-sulphonate, as active metal compounds in a weight ratio calculated as metals of between 0.5% to 99.5% and 99.5% to 0.5%, such as Fe 30% and Ca 70% or Fe 70% and Ca 30% by weight, iii) Fe(π) and/or Fe(III)formate and Mg-carboxylate, mineral salt, oxide or preferably hydroxide as active metal compounds in a weight ratio calculated as metals of between 0.5% to 99.5% and 99.5% to 0.5%, such as Fe 5% and Mg 95% for boiler applications and Fe 50% and Mg 50% for marine and land based diesel application with a preferred dosage of 1 part by weight of the additive to 3000 parts by weight of a fuel and/or crude oil, preferably 1 part by weight of the additive to 500-2000 parts by weight of a fuel and/or crude oil, iv) Fe(II) and/or Fe(IH)formate, Mg-carboxylate, mineral salt, oxide or preferably hydroxide and Ca-carboxylate or mineral salt as active metal compounds in relative quantities calculated as metals of Fe to Mg according to (iii) above and a Ca quantity of between 0.5% and 99.5% by weight, such as would be Fe 20%, Mg 50% and Ca 30% by weight for treating boiler deposits and Fe 25%, Mg 5% and Ca 70% by weight for reducing particulate emissions, v) Fe(H) and/or Fe(E[)formate, Mg and Ca as in (i)-(iv) above and in addition thereto a Ce- and/or Mn-carboxylate, mineral salt, oxide or hydroxide, and vi) formulations as (i)-(v) above using for instance an asphaltene dispersant/stabiliser as disclosed previously in an amount of between 0.1% and 50% by weight based upon the formulation.

A preferred dosage of the additives according to the present invention is suitably found between 0.5 and 5000 ppm, such as 40-60, 0.5-500, 50-200, 2-2000 or 100-1000 ppm, based on the fuel and/or crude oil.

Above preferred formulations are based on the actual active metal combinations. The solids content of liquid combinations can only be limited by the dispersant system adopted and the practical viscosity enabling a dosage pump to operate efficiently. Formulations having a low active metal content are often more applicable to marine and land based diesel engines where dosage requirements take into consideration the type of dosage pump and effective dosage

range and also the importance of the additive distribution in the fuel. The present invention does not prevent addition of further metal compounds as mentioned previously and/or whole or partial replacement of carboxylates mentioned with other metallic salts whether over-based or not.

In a further aspect, the present invention refers to a fuel or crude oil composition comprising a fuel and/or crude oil and at least one additive as disclosed above in an amount of for instance between 0.5 and 5000 ppm, such as 40-60, 0.5-500, 50-200, 2-2000 or 100-1000 ppm. Said fuel and/or crude oil composition is in especially preferred embodiments a furnace or marine fuel oil composition.

hi yet further aspects, the present invention refers the use of a fuel or crude oil additive as disclosed above and to the use of a ferric or ferrous formate in particular in furnace and marine fuel oil compositions for obtaining for instance improved combustion properties, such as reduced smoke and/or particulate emission and/or reduced soot formation, in fuel or crude oil compositions.

The additive according to the present invention and fuel or crude oil compositions comprising said additive have particularly desired characteristics and even synergistic effects of particular component combinations, such as ferric and/or ferrous formate combined with a calcium compound as disclosed above and ferric and/or ferrous formate combined with a cerium and magnesium compound as disclosed above. The use of ferric or ferrous formate in accordance with the present invention yields, moreover, a highly effective combustion enhancer, ensuring for instance complete combustion of fuels and simultaneous decrease in soot formation, hi addition substantial environmental benefits are achieved with reduced flue gas particle emissions and it is, furthermore, possible to obtain biodegradable additives. Additives additionally comprising for example cerium and or magnesium can reduce combustion unit deposits and corrosion.

The present invention vary from combinations known in the of metal compounds as combustion additives/combustion improvers in that overbased metal salts are not used, although combinations comprising overbased metal salts may be permitted. Instead so called all organic metal salts and combinations of all organic metal salts together with inorganic metal salts are used. Enhancement of the combustion additive/combustion improver for liquid products can be achieved by the use of said solvents, dispersants and/or stabilisers providing a more complete combustion and heavy fuel oil stability.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilise the present invention to its fullest extent. The following preferred specific

embodiments are, therefore, to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever, hi the following embodiment Example are fuel oil compositions comprising an additive composition according to the present invention thermogravimetrically and calorimetrically analyses and compared with an oil composition without additive composition and oil compositions comprising ferrous fumarate and Ferrocene, resp., as combustion additive composition. The results are given in Graphs 1-3.

Embodiment and Comparative Examples

Balance from a TA Instrument, model SDT 2960 was used for thermogravimetric tests. The instrument simultaneously provided DSC and TGA analyses. The temperature range of said instrument was from 25 ⁰ C to 1500 ⁰ C, with a heating gradient of from 10°C/min to 100°C/min. Helium, argon, nitrogen, air and oxygen can be used as furnace atmosphere.

The fuel oil used complied with the Venezuelan fuel oil specification and was provided by Ramon Laguna Power Plant, Maracaibo, Venezuela.

The following additives and addition amounts were evaluated: Sample 1: 200 ppm of ferrous formate. Sample 2: 200 ppm of ferric formate.

Sample 3: 200 ppm of ferrous formate + 200 ppm of calcium formate. Sample 4: 200 ppm of ferrous formate + 200 ppm of calcium sulphonate. Sample 5 (Reference 1): 200 ppm of ferrous fumarate. Sample 6 (Reference 2): 200 ppm of Ferrocene. Control: Blank sample without additive.

The test procedure was the same for all samples and the sequence for the thermal analysis was as follows:

- Light materials were first volatilised using nitrogen until the samples reached 400 ⁰ C. The heating gradient was 10°C/min and the nitrogen flow rate was 60 ml/min.

Once the samples reached 400 ⁰ C, air was injected in the furnace at the same flow rate of 60 ml/min. The heating rate was the same as in above reducing step with nitrogen.

- Samples were kept in the furnace up to 700°C.

Mass reduction, heat release and peak temperature were measured by DSC and recorded.

Evaluation was repeated twice and the average was taken for each of the parameters evaluated.

The results are given in enclosed Graphs 1-3 and can be summarised: Ferrous and ferric formate exhibited the highest mass reduction at 4-500°C. Ferrous formate in combination with calcium exhibited the highest mass reduction at 5-600°C. Ferrous or ferric formate in combination with calcium increases the mass reduction at lower temperatures. Ferrous or ferric formate combined with calcium resulted in increased increments in heat release generating the highest amount of energy.

Graph 1

Graph 2

Control Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6

Graph 3