BR102022003667A2 - RENEWABLE FUEL FORMULATION APPLIED IN DIESEL CYCLE AND BASED ON ALCOHOLS - Google Patents

Abstract

“RENEWABLE FUEL FORMULATION APPLIED IN DIESEL CYCLE AND BASED ON ALCOHOLS”, refers to the formulation of renewable fuel, whose objective is to provide a fuel for the diesel cycle that can be produced by biotechnology methods from a renewable biological source, including processes fermentation of sugars or materials available in sugar and alcohol plants. In this way, the fuel obtained can be used conventionally as a substitute for diesel oil in urban or road transport vehicles and be an alternative option to the oil used in sugar and alcohol plants, which reduces the emission of fossil carbon in the production cycle of sugar and alcohol, offering an alternative energy supply for systems started by compression, with advantages of replacing fossil sources, reducing the emission of carbon compounds, adequate consumption, compatible cost, maintenance of the useful life of the system components, greater safety and reduced evaporation losses.

Description

RENEWABLE FUEL FORMULATION APPLIED IN DIESEL CYCLE AND BASED ON ALCOHOLS

[01] This patent refers to the formulation of renewable fuel, whose objective is to provide a fuel for the diesel cycle that is possible to produce by biotechnology methods from a renewable biological source, including fermentation processes of sugars or materials available in sugar and alcohol plants. In this way, the fuel obtained can be used conventionally as a substitute for diesel oil in urban or road transport vehicles and be an alternative option to diesel oil used in sugar and alcohol plants, which reduces fossil carbon emissions in the production cycle. of sugar and alcohol, with the advantages of replacing fossil sources, reducing the emission of carbon compounds, adequate consumption, compatible cost, maintenance of the useful life of the system components, greater safety and reduced evaporation losses.

[02] Internal combustion engines with compression ignition (diesel cycle engines) have been known since the pioneering work of Rudolph Diesel, who demonstrated the possibility and suitability of heat engines in which fuel ignition occurs by heating the air-to-air mixture. fuel caused only by compressing the mixture in the combustion chamber, without the need to use a spark generated by an electrical system, as occurs in spark ignition engines (Otto cycle engines). Diesel cycle engines are generally 30% more efficient in converting thermal energy into mechanical energy than Otto cycle engines of the same power. For this reason, they are widely used in trucks, buses, civil construction machines, agricultural machines, electricity generators, irrigation pumps, automobiles, trains and ships. Modern diesel engines, used mainly in passenger cars, have low emission of harmful gases. When compared to Otto engines of equivalent power, they present a reduction in carbon dioxide emissions, precisely because of the greater energy conversion efficiency. However, the vast majority of existing diesel engines use diesel oil, a fossil fuel that contributes to the greenhouse effect and emits harmful and polluting products, mainly particulate matter, nitrogen oxides and sulfur derivatives.

[03] Currently, there is a clear trend towards the development of fuels of biological origin (biofuels), which have a production cycle in which at least part of the carbon emitted during the burning of a biofuel is recovered by the process of biological growth, in general by capturing atmospheric carbon in the process of photosynthesis. Agricultural production cycles, however, add carbon in various stages of the biofuel manufacturing process, in particular through the consumption of fossil diesel oil in agricultural machinery, trucks, and irrigation motor pumps. The production cycle of ethanol from sugarcane, for example, is one of the most efficient in capturing carbon, but uses diesel fuel intensively. One of the objectives of this invention is to provide a fuel for the diesel cycle that is possible to produce by biotechnology methods, including fermentation processes of sugars or materials available in sugar and alcohol plants. In this way, the fuel could be an alternative option to diesel oil used in sugar and alcohol plants, which reduces fossil carbon emissions in the sugar and alcohol production cycle.

[04] Among biofuels, the most widely used is ethanol, in spark ignition engines (Otto cycle), either as a component mixed with gasoline or as a relatively pure fuel. Ethanol has a high octane rating, that is, an anti-knock characteristic suitable for spark ignition. In this way, it can provide the proper octane rating to gasoline, replacing tetraethyl lead, a toxic compound. When used in a mixture with gasoline, ethanol is anhydrous, since the presence of water prevents a stable mixture with gasoline. When used without another mixture in Otto cycle engines, ethanol is hydrated. Ethanol is used in several countries mixed with gasoline, arriving in Europe and the United States to represent 85% of the mixture with gasoline (E85). In Brazil, pure hydrated alcohol is widely used.

• - O etanol apresenta um baixo poder calorífico em relação à gasolina. Em média, o conteúdo energético do etanol hidratado é de apenas 70 % do conteúdo energético da gasolina com 22 % de etanol (mistura fornecida ao mercado brasileiro); e
• - O etanol hidratado apresenta uma maior corrosividade, quando comparado à gasolina.

[05] However, ethanol has some inherent technical problems:

• - Ethanol has a low calorific value compared to gasoline. On average, the energy content of hydrated ethanol is only 70% of the energy content of gasoline with 22% ethanol (blend supplied to the Brazilian market); It is
• - Hydrated ethanol is more corrosive when compared to gasoline.

[06] Technologies that allow the use of ethanol or alcohols in compression ignition engines (diesel cycle) include mixtures and emulsions of ethanol and/or other alcohols in diesel oil or petroleum fractions. Frequently, such mixtures or emulsions employ butanol or isobutanol as a co-solvent, an auxiliary with an intermediate polar character between ethanol and hydrocarbons, in order to increase the stability of the mixture.

[07] The mixtures tried and taken to the market present stability problems, since ethanol and diesel oil are not very miscible with each other. Many present separation problems some time after mixing, problems that are aggravated by environmental conditions such as low temperatures, air humidity, etc. Problems of degradation of surfaces by cavitation and corrosion occur frequently, due to the physical separation between the components caused by friction efforts and differences in dynamic pressure found in pumping and fuel injection systems. In addition, these mixtures still do not represent a completely renewable fuel, as they use fossil fuels in large proportions.

[08] Another current technology is the mixture of additives to hydrated ethanol capable of increasing the explosiveness of ethanol, in order to allow its ignition by compression.

[09] 2-EHN and organic peroxides are conventionally used to increase the explosiveness of diesel oil, but not to add to ethanol, as their curves of added content x increase in the number of cetanes tend to an asymptote after 8%, but it does not reach the cetane number of 42 necessary for proper ignition of diesel oil or hydrous ethanol.

[010] All organic nitrates have stability problems (acid or alkaline hydrolysis), especially in the presence of water. Hydrated ethanol, due to its water content, has a tendency to hydrolyse, generating free acid that increases with the period of storage. It shows corrosion of the injector nozzles. Even in media without nitrates, durability is reduced by the presence of water vapor near the injection nozzle and exhaust valves. For this reason, the maintenance of hydrous ethanol systems takes less time compared to diesel oil systems. For example, Scania's maintenance manual for the BEST (BioEthanol for Sustainable Transportation) project buses indicates changing the injector nozzle every 22,000 km, while changing the nozzles in systems with diesel oil occurs every 120,000 km.

[011] In addition to the durability problems inherent to hydrated ethanol, due to the great difference in calorific value of ethanol compared to diesel, there is an increase in consumption in L/h in the ratio L/h of ethanol/L/h of diesel between 1 .5 and 2.0. This higher consumption, combined with the cost of additives, tends to make ethanol projects economically unfeasible, which are very important from an environmental point of view.

[012] Another technology for using ethanol in vehicle engines and equipment conventionally operating on a diesel cycle consists of the so-called “ottolization”, that is, transforming engines originally running on a diesel cycle to run on an Otto cycle, by adapting a spark plug in a diesel engine cylinder head. Such a conversion, in addition to implying cost and time to be carried out, being difficult to reverse, implies increases in the consumption ratio L/h ethanol / L/h diesel above 2.0, since the Otto cycle has an efficiency of energy conversion about 30% lower than that of the diesel cycle of equivalent power.

[013] Searching the Brazilian and international patent databases, we found the following revelations:

[014] The following patents are for mixtures of alternative fuels to diesel:

[015] Chinese patents with publication number CN 101602968 and CN101434875 reveal options for blending hydrocarbons with ethanol.

[016] Patent CN 101580743 discloses a diesel fuel or gasoline composed of a mixture of combustible materials, tar, and solvents derived from industrial or organic waste, 10-50% of alcohols or mixtures that may include butanol, 10-15% of butanol, isopropanol, d-tert-butyl-p-cresol or mixtures thereof, 10-25% iron-diene ring, or kerosene, solvent oil, mineral oil, lubricating oil, vegetable oil or mixtures thereof. This patent does not substantially employ butanol as the primary fuel.

[017] Patent CN 101402887 deals with a compound substantially of ethanol (75 to 90%) to act as diesel oil for low temperatures, containing, among other compounds, 2 to 10% of butanol or isobutanol. Butanol basically acts as a co-solvent for the various compounds.

[018] Patent CN 101376848 describes an ethanol-diesel mixture with a proportion between 60-85% of diesel oil. Butanol is used in a content between 0.5 and 1.5%, as a co-solvent to aid in the stability of the resulting emulsion.

[019] The US patent 2009013591 shows a mixture of fuels that includes 15-95% of gasoline or diesel oil, 5 to 85% of alcohols, including butanol, characterized by the use of glycerin ethers as an additive.

[020] The Chinese patent CN 101235325 reveals a diesel oil-methanol mixture, with diesel oil 23-50%, methanol 35-70%, where two of several other constituents are: isobutanol 0-3% and butanol 0-3%.

[021] The Chinese patent CN 101215483 presents a diesel-methanol mixture comprising, among other components, 0.25 -0.6% tert-butanol.

[022] Patent CN 1800313 discloses an emulsion of gasoline with alcohols and dimethyl ether that may contain 2-3% of 2-butanol.

[023] Patent CN 1730619 presents an emulsion fuel containing methanol, petroleum, diesel oil, tert-butanol, sorbic alcohol fatty acid ester, polyoxyethylene, and monomethoxypolyethylene.

[024] Patent CN 1796513 describes an additive to be added to diesel oil, comprising ethanol, ketones, silicones, n-butanol, and benzyl alcohols.

[025] Patent CN 1769398 shows a fuel with 65-80% methanol, which may contain, among others, 5-10% butanol.

[026] Patent CN 1590515 describes a fuel formed by mixing diesel oil, benzene, gasoline, butanol and fatty acid ammonium salt.

[027] The following patents are for additives to improve the ignitability of diesel oil or ethanol:

[028] Patent EP 0403516 discloses a polyalkylene glycol additive to be added to hydrated ethanol in a proportion between 12-20%, but the examples show adequate results in polyalkylene glycol contents greater than 17% for conventional engines with typical compression ratios of 18:1.

[029] US patent 5,628,805 describes an ethoxylated polyol to be added to hydrated ethanol in a proportion between 5 and 10% v/v. This technology is currently in use in the city of Stockholm (Sweden), and being tested in several cities around the world, applied in Scania engines, through the BEST project (BioEthanol for Sustainable Transportation). However, to be used in the proportion of 5%, an engine specially designed for the fuel is required, with a higher compression ratio than that used in conventional diesel engines. While the compression ratio of conventional diesel engines is around 17:1, the compression ratio of Scania diesel cycle engines dedicated to ethanol is around 24:1. This limits its use to dedicated engines, and prevents the technology from being of the "flexfuel" type, that is, neither the fuel formulated in this way can be used in the wide base of existing conventional engines, nor the engines dedicated to ethanol can be used with the suitable diesel fuels at conventional compression ratios (diesel oil, biodiesel, vegetable oil, etc.).

[030] US patent 2,378,466 discloses the use of organic nitrates such as ethyl nitrate, ethylene glycol dinitrate (DNMEG), triethylene glycol dinitrate (DNTEG), tetraethylene glycol dinitrate (DNTetraEG), as additives capable of increasing ignition of diesel oil.

[031] Recently, alternative options for ethanol from renewable sources have emerged. Among the options, 4-carbon alcohols, mainly n-butanol and isobutanol, can be produced by renewable biotechnology processes, with advantages such as a calorific value slightly lower than that of gasoline, greater solubility in hydrocarbons, lower corrosivity, higher flash and boiling points, which makes handling and storage of the fuel safer and reduces evaporation losses.

[032] The conventional process for the production of butanol by microbiological fermentation is the ABE process (Acetone Butanol Ethanol), which employs fermentation of sugars by the bacterium Clostridium acetobutylicum. Introduced at the beginning of the 20th century by the industrial chemist, leader of the Zionist movement and first president of the State of Israel Chaim Weizmann, the process focused on the production of acetone used on a large scale to obtain the explosive Cordite (a double-base gunpowder). Later, the process was supplanted in terms of economic viability by petrochemical processes and fell into disuse.

[033] A line of development widely used today is the genetic modification of bacteria of the genus Clostridium, which increases the productivity and selectivity of the ABE process to maximize the production of butanol. Such a line of development includes, as n-butanol production processes, the patents US 5,753,474, US 2010143996, US 2010136641, CA 2699378, WO 2010024715, WO 2010024714, GB 2462642, WO 2010017230, US 201 0036174, RU 2375451, CN 101595218, WO 2009149270, KR 2010019127, US 2010086982, WO 2009142541, GB 2459756, CN 101423815, CN 101250496, and JP 60172289.

[034] The Canadian patent CA 2548221 discloses a new bacterium, Clostridium carboxidivorans, which can synthesize biofuels from CO, including ethanol, and catalyze the production of acetate and butanol. It can also directly ferment lignocellulose to produce ethanol or other substances.

[035] The patents US 2009275787, and WO 2010031793 employ modified Clostridium bacteria to produce n-butanol from glycerin. This process is of particular interest, since large volumes of glycerin are obtained in the process of transesterification of fatty acids (biodiesel production), and there is no demand for the expected volume of glycerin that should enter the Brazilian market due to the increase in biodiesel content. in diesel oil.

[036] US patent 2010093020 employs bacteria of the genus Enterococcus genetically modified for optimized production of butanol.

[037] The patent WO 2009122192 employs, for the production of butanol, genetic modification of bacteria of the Bacillaceae family, preferably Geobacillus or Ureibacillus.

[038] Patent WO 2009082690 employs modification of the genetic code of various bacteria for the production of butanol,

[039] US patents 2010143985, US 2010129885, US 2010062505, WO 2009140159, WO 2009013159 disclose, for the production of butanol, genetically modified yeasts. Yeasts have the advantage of being normally used for ethanol production, making the process adaptation of existing sugar and alcohol plants easier.

[040] The Canadian patent CA 2691998 employs genetic modification of bacteria or yeast for the production of butanol.

[041] Patent WO 2009105733 discloses a photosynthetic process that uses plants, algae, blue-green algae, which can produce butanol directly from CO2 and water. In this way, there is a direct sequestration of carbon from the atmosphere, with better energy use in the process, and reduced competition between the biofuel production process and food production.

[042] Patent KR 20090025221 shows a process that uses algae to generate biomass, and then transform it into alcohols or ketones, including butanol.

[043] Patent WO 200900346 discloses a process that converts CO2 into gases, and subsequently uses fermentation of these gases to obtain products, including butanol.

[044] The patents WO 2009103533, CA 2684860, WO 2009086423, and WO 2010037111 disclose modifications in yeast for the production of isobutanol.

[045] The patent WO 2009149240 discloses a process for the production of isobutanol from fermentation of biomass by bacteria of the species Escherichia coli.

[046] The following patents reveal unspecified cells modified for the production of butanol and ethanol: WO 2009013160, US 2009176288, WO 2009082148, WO 2008124523, WO 2009059254, and WO 2008143704.

[047] The patent WO 2009078973 presents genetic modifications in microorganisms for the production of several valuable products, including butanol, from free fatty acids.

[048] Patent CN 101358187 provides for the use of gamma radiation to modify cells or protoplasts to increase the yield of butanol production.

[049] Several processes employ conventional microorganisms from fermentation processes without genetic modification, but optimize the yield of the industrial process for obtaining butanol, or the process of separating butanol from the fermentation broth, which increases yield, because even low levels of butanol make the fermentation medium toxic to alcohol-producing micro-organisms. As patents that reveal process changes we can mention: NL 10355651, KR 100556322, WO 2010011769, CN 201367402, US 2008274524, WO 2010000649, US 2010105115, WO 2009106835, WO 200911 2335, WO 2009100434, CN 101475932, US 2009162912, WO 2009087680, WO 2009079362, CN 101418320, CN 101397236, CN 101429527, WO 2009062601, US 2009017514, CN 101363031, WO 2009021503, CN 101333545, WO 2009 008616, WO 2008154301, CN 101302545, CN 101250561, WO 2008124490, CN 101333545, CN101457238, DE 102006060610 and WO 2009079213.

[050] Patent CN 101165188 demonstrates the production of butanol from ground cassava or cassava starch.

[051] US patent 2010087687 discloses a process to take advantage of plant biomass, animal or municipal waste, which includes butanol among the products.

[052] Patent MX 2009006782 shows a process for producing biofuels, which includes biobutanol, from enzymes.

[053] The patent WO 2009128644 shows a metabolic network model for analyzing the metabolic characteristics of butanol-producing microorganisms, and methods for selecting or modifying microorganisms in order to obtain metabolic products with high efficiency.

[054] Several patents present the approach, from ethanol produced biologically, to produce butanol chemically.

[055] US patents 2010058654, JP 2009220105, WO 2009097312, KR 20090009330, JP 2008088140, and RU 2191769 present catalysts for processes that can convert ethanol produced from renewable sources into butanol.

[056] US patent 20150166443 uses gallium catalysts to produce higher alcohols, between 4 and 8 carbons, from ethanol, which may be of biological origin.

[057] Although it is desirable that butanol becomes an economically viable fuel produced from renewable and biological sources (so called biobutanol), solutions for petrochemical processes for obtaining butanol are still patented:

[058] US patent 2010048960 discloses a process for producing butanol from butane.

[059] US patent 2009239275 shows a process to produce 2-butanol by petrochemical means.

[060] The patent WO 2005108593 discloses an enzymatic catalyst for the production of 2-butanol from 2-butanone.

[061] Patent KR 20080106516 discloses a process for producing butanol from butene.

[062] Patent MX 2009008416 discloses a process for the production of various alcohols, including n-butanol and isobutanol.

[063] The following patents reveal fuels that use butanol as part of their composition:

[064] US patent 2010005709 demonstrates a mixture of ethanol, isopropanol, and sec- or tert-butanol, not more than 3% methanol and not more than 15% C5 or greater. The obtaining process is a petrochemical process of the Fischer-Tropsch type (obtaining alkanes from carbon monoxide and hydrogen), and the mixture is used as fuel for Otto cycle engines (gasoline).

[065] US patent 2009277079 discloses a mixture to be used as gasoline of butanol isomers with good cold start.

[066] WO 2009120042 patent shows a process to chemically produce butyl butyrate from butyric acid and butanol from fermentation. The ester can be used as biodiesel.

[067] Patent WO 2009114752 presents a process for using xenobiotic materials that are carbon sources to produce biomass and/or biogas from microorganisms that degrade carbon sources, and then use microorganisms to synthesize biofuels. One of the mentioned biofuels is butanol.

[068] Patent WO 2009106647 discloses an engine with compression ignition comprising two injection systems, where one system injects diesel or biodiesel, and the other injects a fuel more volatile than diesel, such as hydrogen, LPG, natural gas, ethanol , propanol or butanol. Such bi-fuel hybrid systems have recently been presented to the market by several companies, always with a utilization ratio between the two fuels close to 50%/50%, with some disadvantages: need for two fuel tanks, separate transport/supply logistics for two fuels, a sophisticated variable fuel injection control system according to the required power load, and the purchase by the user of an injection system modification kit.

[069] US patent 2009151232 discloses a composition of light diesel oil containing between 9 and 20% of butanol, 0.4 to 4% of butyl nitrate or nitrite, and the remainder of base for light diesel oil, that is, it employs a substantial amount (between 90.6 and 76%) of diesel oil derived from petroleum.

[070] Patent CN 101402888 presents an additive compound and a methanol diesel fuel, containing, among others, 1 to 10% of n-butanol. n-Butanol acts as a co-solvent, but substantially the fuel is composed of methanol, which has a low calorific value and is extremely toxic.

[071] Patent KR 20090003146 demonstrates a mixture to replace gasoline (Otto cycle engines), composed mainly of ethanol or methanol, containing between 5 and 8% of butanol.

[072] Patent CN 101240199 shows an alcohol-ether mixture (65 to 70%), where the alcohol is a mixture of methanol, butanol and acetone, and the ether is the mixture of any 2 ethers comprising dimethyl ether, isopropyl ether or methyl tert-butyl ether (MTBE).

[073] US patent 2010005709 discloses a process to produce alternative fuels, which includes obtaining synthesis gas from renewable sources, converting this gas into olefins with a chain substantially between C2 and C4, and hydrolyzing these olefins. The resulting mixture of alcohols contains butanol and must be mixed with gasoline.

[074] Patent MX 2007010015 presents a mixture of alcohols from Cl to C5 or Cl to C8, with more ethanol than methanol, with a higher octane rating than ethanol, that is, to replace gasoline.

[075] Patent CN 101085938 discloses a synthetic biofuel with 10-50% petroleum-derived fuel, such as naphtha, dimethyl ether and gasoline, 4.5-10% of one or more of the list that includes ether, acetone or butanol.

[076] The patent CN 1884440 deals with the production of tert-butyl fatty acid ester (biodiesel), using tert-butanol as a transesterification reagent.

[077] Patent JP 2004285346 comprises a fuel to replace gasoline, composed of ethanol, and at least two compounds from the group consisting of diisopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, dipropyl ether, tert -butanol, dibutyl ether and diethyl ether.

[078] Patent KR 20040044677 discloses an alternative fuel composed of 50-80% of mixed coal liquid extract extracted from bituminous coal, 10-20% of ethanol or methanol from coal liquefaction, 5-15% of n-butanol extracted from coal liquefaction, and 5-10% of toluene extracted from coal liquefaction.

[079] Patent KR 20020009543 presents an alcohol-based fuel to replace gasoline composed of, among others, 5-15% of butanol.

[080] Patent KR 20030006529 comprises a fuel for internal combustion engines, Otto cycle, composed, among others, of 3-7% of butanol.

[081] The patent RU 2148075 shows compositions based on diesel oil, containing 0.0065-0.0075% oligoethyl siloxane hydride and 0.0025-0.0035% by weight of butanol.

[082] The patent WO 9324593 discloses a diesel fuel containing between 10 and 35% of ethanol in mixture with diesel oil, also containing butanol and an alkyl peroxide.

[083] Patent KR 930011071 deals with a fuel in emulsion of 1000 parts of petroleum (gasoline?), 15-70 parts of siloxane or oxosilane, 100-300 parts of butanol, 3-7 parts of methanol, 10-20 parts of polyethylene glycol, and 1-3 parts of non-ionic surfactant.

[084] Patent JP 2022388 presents a fuel in the form of an emulsion of an alcohol (methanol, ethanol, or butanol), benzene, toluene or xylene, and a fraction rich in aromatics from the distillation of catalytic cracking fluid from an oil refinery .

[085] The European patent EP 0171440 discloses a fuel for motors based on a fuel composed basically of hydrocarbons, which additionally contains alcohols, and optionally ethers, ketones, aromatics, additives and lead compounds, which may contain 0-10% of butanol.

[086] Patent CA 1221539 describes a stable composition of gasoline and ethanol, containing an additional alcohol, which may be, among others, n-butanol and isobutanol.

[087] US patent 4526586 comprises microemulsions from vegetable oil, a C1-C3 alcohol, water and 1-butanol as a non-ionic surfactant.

[088] Patent GB 2090612 shows a mixture for use as diesel oil containing between 10 and 60% by volume of diesel, 10-60% of a C1-C8 alkyl ester of a C12-22 fatty acid, and 10-50 % of a mixture containing at least n-butanol and acetone.

[089] US patent 4,398,920 deals with a mixture of fuel containing: (a) gasoline, diesel, or fuel oil, (b) a mixture of butanol and acetone, optionally containing isopropanol and/or ethanol; and (c) methanol, where the butanol/acetone mixture (b) is prepared by fermentation by suitable organisms such as bacteria or fungi.

[090] US patent 4,368,056 discloses a fuel formed by mixing butanol obtained by fermentation and glycerides obtained by fermentation, where the substrates are industrial waste, such as cheese yeast, corn cobs, wood chips, etc.

[091] US patent 4300912 describes a synthetic fuel composed of long-chain macromolecules formed by distillation links of methanol, butanol and a kerosene-type oil with a colloidal stabilizer.

[092] In all these patents, the use of alcohol isomers of butanol as fuel for Otto cycle engines, that is, suitable for spark ignition, or fuel mixtures for diesel cycle engines that eventually contain butanol or its alcohol isomers are disclosed. , but never with butanol and alcohol isomers as main fuels.

[093] Butanol, isobutanol or another alcohol isomer of butanol, by itself, does not have characteristics similar to diesel oil, which are necessary to function properly in diesel cycle engines, as shown below:

[094] - Butanol and its isomers have a high octane rating, that is, resistance to compression detonation, a characteristic that is very desirable in fuels for Otto cycle engines, but opposite to the desirable characteristic for fuels for diesel cycle engines. On the contrary, diesel fuels must have a high number of cetanes, that is, a greater explosiveness when started by compression. The specifications of the diesel oil used in Brazil require a cetane number equal to or greater than 42, according to ASTM D 613 (measurement in a single-cylinder engine type CFR) or ASTM D 6890 (measurement of ignition delay in a combustion chamber of constant volume type IQT). Low cetane numbers mean that it is difficult to start the engine cold, or even that the fuel does not ignite under compression, with total engine stoppage and accumulation of unburned liquid fuel inside the engine cylinder.

[095] - Butanol and its isomers, despite having a similar viscosity to diesel oil, do not have lubricity comparable to diesel oil, especially those types of diesel oil with a high sulfur content. Low lubricity wears out the injection systems, especially the rotors of common rail injection pumps, where the pressures and frictional efforts are very high, locks exhaust valves, causes premature wear and "fluttering" of rings, that is, a series of deleterious effects on the components of the injection systems and on the engines. According to Brazilian standards, diesel oil must show a maximum wear of 460 μm in a HFRR (High Frequency Reciprocating Rig) lubricity test, in accordance with ASTM D 6079.

[096] - Alcohols, despite the fact that butanol and its isomers present a lower corrosive aggressiveness when compared to hydrated ethanol, present a greater corrosion of materials when compared to diesel oil, generating wear problems to the materials of the injection system.

[097] - Alcohol isomers of butanol are oxidized by oxygen in the air during storage, generating butyric acids, which have an extremely unpleasant odor, which can be resolved by adding an antioxidant additive.

[098] The Brazilian patent PI 1004630-5, owned by the inventor of the present patent, brought an option to allow the use of 4-carbon alcohols through an optimized formulation that uses a series of cetane-improving products, including triethylene glycol dinitrate, tetraethylene glycol dinitrate, isoamyl nitrate, among others, capable of increasing the explosiveness of the combustible mixture, in addition to lubricants, stabilizers and anticorrosives. However, the products used as the main additive to improve cetanes are still derived from petroleum, which takes this fraction of the fuel from a non-renewable carbon source, in addition to having a higher production cost.

[099] This patent expands the range of cetane-improving products through proprietary synthesis products and previously never used as fuel additives, as well as expanding the range of alcohol-based renewable diesel cycle fuel formulations.

[0100] With the increased use of biodiesel based on fatty acid esters, the chemical market was impacted by a large supply of glycerin, a by-product of the biodiesel industry. This generated a surplus volume of glycerin compared to the demand, which brought the opportunity for syntheses that use glycerin of vegetable origin, renewable, and of low cost, in products that add value to this chain.

[0101] Among the recently developed products derived from vegetable glycerin are glycol ethers. This class of compounds can be conveniently synthesized from glycerin and alcohols, such as ethanol and butanol, by replacing one or more hydroxyls of glycerin with ether radicals. Since glycerin can be of vegetable origin, as well as alcohols, the compound can be considered a renewable source.

[0102] Polyglycols are a class of polymeric compounds (polyethers) obtained from the polymerization of epoxide units, such as ethylene oxide or propylene oxide, or glycol monomers, such as ethylene glycol or propylene glycol. Polyglycols can also be produced from a renewable source, either by dehydration of alcohols obtaining alkenes, and subsequent oxidation of alkenes, obtaining epoxides, such as dehydration of ethanol, obtaining ethylene, followed by oxidation of ethylene, obtaining oxide of ethylene.

[0103] "RENEWABLE FUEL FORMULATION APPLIED IN DIESEL CYCLE AND BASED ON ALCOHOL", object of this patent, was developed to offer an alternative energy supply for systems started by compression, from a renewable biological source, with substitution advantages from fossil sources, reduction of the emission of carbon compounds, adequate consumption, compatible cost, maintenance of the useful life of the system components, greater security and reduced evaporation losses. The fuel of the present patent is capable of replacing diesel oil, is based on substantial proportions of 4-carbon alcohol, such as n-butanol, isobutanol, sec-butanol and tert-butanol and is an alternative coming from renewable sources, produced in sugar and alcohol plants, and can remove the fossil fuel used in large quantities in the sugar and ethanol production cycle, in irrigation motor pumps, tractors, sugarcane transport trucks, sugarcane harvesters, tractors and support trucks. Another interesting application will be as fuel for urban buses, as the environmental laws of several states and municipalities in Brazil include ambitious targets for reducing the use of fossil fuels.

[0104] The original and unprecedented concept of the invention came from the inventor's previous experience with respect to the relative effectiveness of cetane-enhancing agents, lubricants and anticorrosives. According to his previous research, cetane enhancers, which promote the explosion of the air-fuel mixture by compression, consequently reducing the ignition time (the time elapsed between the fuel injection and its effective detonation), act through bond breaking mechanisms molecules, either by oxidation-reduction internal to the molecule, or by formation of free radicals, or by cleavage. The relevant literature explains part of these mechanisms. An important source is the article “How Do Diesel-fuel Ignition Improvers Work?” by P.Q.E. Clothier et allii, University of York, Toronto, Canada, published in the Chemical Society Review, in 1993.

[0105] As a typical example of compounds subject to oxidation-reduction reactions internal to the molecule, we can cite organic nitrates, as an example of compounds subject to free radical formation reactions we can cite organic peroxides, and as an example of compounds subject to ether cleavage and polyethers.

[0106] From the experimental observations of the author of this patent over more than 20 years of research with cetane improvers, lubricants and anticorrosives, it would be possible to find a synergy between mechanisms. One of the teachings of the present invention is the synergy between the mechanisms that promote the rapid detonation of the air-fuel mixture under compression, which surprisingly made it possible to reduce the percentage of cetane improver needed, as well as allowing the use of a cetane improver compound as a lubricant . This synergy makes it possible to reduce production costs, as nitrates are generally more expensive than polyglycols.

[0107] Another objective of the present invention was to provide a fuel whose characteristics are as similar as possible to those of diesel oil derived from petroleum, in order to provide its use in any diesel engine currently available, practically without modifications. The only change envisaged is an increase in the delivery of the injection pump, to compensate for the increase in consumption, which from previous experience will be around 15% to 20%.

[0108] The bases of the invention consist in combining the 4-carbon alcohol with an organic dinitrate ester compound, derived from glycerine glycol monoether, or a polyethylene glycol nitrate, any of these in synergistic combination with a polyglycol, which as a co - cetane-improving additive, in addition to its known function as a lubricant. The final effect was surprising, the synergistic mechanism is not explained, but it can be attributed perhaps to the interaction between the acidic nitrogen oxides formed in the gas phase by the nitrate, and the polyglycol, where the nitrogen oxides catalyze the cleavage of the C-O bonds of the polyglycol , forming highly reactive carbocations.

[0109] Glycolic ether can be synthesized from vegetable glycerin and n-butanol, by reactions known in the industry, and which are not the subject of this patent. Polyglycol can conveniently be produced from ethanol via dehydration, oxidation, and polymerization, or any other process known in the industry.

[0110] The dinitrates, later tested as possible cetane-improving products for butanol, were synthesized as described in the Brazilian patent BR 10 2021 003924-8 by the same inventor of the present patent.

• - Preparação de mistura ácido nítrico 99 % e oleum sulfúrico (ácido sulfúrico com 34 % de SO3 livre), na proporção de 70 % de ácido nítrico e 30 % de oleum, em massa;
• - Resfriamento, sob agitação, de 167 g desta mistura;
• - Adição gota-a-gota, de 180 g de polietileno glicol de massa molecular média 200 daltons, sob agitação intensa e resfriamento, mantendo uma temperatura máxima de 5 °C;
• - Separação dos nitratos formados por adição de 3000 mL de água destilada;
• - Retirada da fração de nitratos em funil de separação;
• - Lavagem do nitrato resultante 5 vezes em 3000 mL de água a cada lavagem, à temperatura ambiente; e
• - Separação dos nitratos formados em funil de separação.

[0111] A polyethylene glycol dinitrate was also synthesized by the following procedure:

• - Preparation of a 99% nitric acid and sulfuric oleum mixture (sulfuric acid with 34% free SO3), in the proportion of 70% nitric acid and 30% oleum, by mass;
• - Cooling, under agitation, of 167 g of this mixture;
• - Dropwise addition of 180 g of polyethylene glycol with an average molecular mass of 200 daltons, under intense agitation and cooling, maintaining a maximum temperature of 5 °C;
• - Separation of nitrates formed by adding 3000 mL of distilled water;
• - Removal of the nitrate fraction in a separating funnel;
• - Washing of the resulting nitrate 5 times in 3000 mL of water for each wash, at room temperature; It is
• - Separation of the nitrates formed in a separating funnel.

[0112] The purified products mentioned above were used in mixtures with 4-carbon alcohols, in performance tests as described below:

• • Marca: RAX;
• • Modelo: RD7;
• • Fabricante: Motoren u. Maschinenfabrik Felix Renauer (Áustria);
• • Características: Motor Diesel de injeção indireta, monocilíndrico, simples efeito;
• • Relação de compressão volumétrica 16,8:1,0;
• • Potência: 7 cv a 1400 RPM;

- Gerador Elétrico, acoplado ao motor para dar Carga Efetiva;

• • Marca: Sociedade Industrial Máquinas Elétricas “LEMIS”;
• • Modelo: GA 15/12;
• • Potência: 3 kVA 220/110V; 13,5/27 A a 1500/1800 RPM;
• • Acoplamento: Correia Plana com relação de transmissão de 1:1,83;
• • Carga Efetiva controlada por reostato e dissipada em tanque de salmoura;

- Sistema de aquisição de dados;
- Pressão da câmara de combustão;

• • Sensor Piezelétríco para 250 Kgf/cm2;
• • Marca: Kistler AG;

- Pressão da linha de injeção;

• • Sensor Indutivo para 350 Kgf/cm2;
• • Marca: Hartmann & Braun;

- Registro dos sinais de pressão;

• • Osciloscópio digital de 4 Canais, 100 MHz;
• • Marca: Agilent, modelo DSO 6014 A;

- Metodologia do Ensaio;
As variações das pressões no interior do cilindro (câmara de combustão) e na tubulação de alta pressão do sistema de injeção foram efetuadas com dois transdutores de pressão;
Os sinais provenientes dos transdutores são amplificados, tratados e em seguida enviados ao osciloscópio; e
O osciloscópio foi regulado de modo a indicar, em sua escala vertical, as variações de pressão no interior do cilindro (câmara de combustão) e a pressão na tubulação de alta pressão do sistema de injeção. A diferença de tempo entre o pico de pressão no sistema de injeção, indicando abertura da agulha do bico injetor, e o início do pico de pressão no interior da câmara de combustão, indicativo da detonação do combustível, é medido como o tempo de atraso de ignição.[0113] Test I: Ignition delay test in a single-cylinder engine, with the following methodology:
- Stationary diesel engine;

• • Brand: RAX;
• • Model: RD7;
• • Manufacturer: Motoren u. Maschinenfabrik Felix Renauer (Austria);
• • Characteristics: Single-cylinder, single-acting, indirect injection diesel engine;
• • Volumetric compression ratio 16.8:1.0;
• • Power: 7 hp at 1400 RPM;

- Electric Generator, coupled to the engine to provide Effective Load;

• • Brand: Sociedade Industrial Máquinas Elétricas “LEMIS”;
• • Model: GA 15/12;
• • Power: 3 kVA 220/110V; 13.5/27 A at 1500/1800 RPM;
• • Coupling: Flat Belt with transmission ratio of 1:1.83;
• • Effective charge controlled by rheostat and dissipated in brine tank;

- Data acquisition system;
- Combustion chamber pressure;

• • Piezoelectric sensor for 250 Kgf/cm2;
• • Brand: Kistler AG;

- Injection line pressure;

• • Inductive Sensor for 350 Kgf/cm2;
• • Brand: Hartmann &Braun;

- Recording of pressure signals;

• • 4-Channel Digital Oscilloscope, 100 MHz;
• • Brand: Agilent, model DSO 6014 A;

- Test Methodology;
Pressure variations inside the cylinder (combustion chamber) and in the high pressure pipe of the injection system were carried out with two pressure transducers;
The signals coming from the transducers are amplified, treated and then sent to the oscilloscope; It is
The oscilloscope was adjusted so as to indicate, on its vertical scale, the pressure variations inside the cylinder (combustion chamber) and the pressure in the high pressure piping of the injection system. The time difference between the peak pressure in the injection system, indicating opening of the injector needle, and the beginning of the peak pressure inside the combustion chamber, indicative of fuel detonation, is measured as the delay time of ignition.

[0114] The applied load control was performed by the electrical generator excitation control rheostat determining the voltage readings (Volts) and electric current (Amps) allowing the calculation of the effective load applied to the engine by means of the generator.

[0115] The loads applied to the motor were determined, having as maximum limits generated electrical powers of the order of 2.8 hp.
Test II: Diameter of wear scar on steel ball for evaluation of lubricity in HFRR (High Frequency Reciprocating Rig) equipment, according to ASTM D 6079; It is
The tests were carried out comparatively to diesel oil, in order to select the ranges of contents optimized in efficiency for the tested additives. The aim was to obtain an ignition delay similar to or less than the ignition delay of unloaded and loaded diesel, and from previous experience an ignition delay of no more than 5% greater than that of diesel under the same conditions was established as a standard. Therefore, a maximum delay of 1.05 ms in the unloaded condition and 1.32 ms in the loaded condition, and an HFRR lubricity with a maximum scar diameter of 460 µm was established as the limit for choosing the appropriate formulation.

[0116] Table I: Ignition efficiency test results:

[0117] Surprisingly, blends based on butanol and isobutanol that used polyethylene glycol as a lubricant also had ignition delay equal to or less than diesel with substantially lower nitrate contents than blends that only contained nitrates. As confirmation of the synergistic effect, mixtures containing similar proportions of polyethylene glycol only without nitrates did not even detonate upon compression. Polyglycol was also effective as a lubricant, reducing the HFRR test scar to diesel-like levels.

• - entre 89 e 98 % de um combustível álcool de 4 carbonos, tais como n-butanol, isobutanol, sec-butanol e terc-butanol;
• - entre 0,5 e 10 % de um ou mais nitratos capazes de aumentar a explosividade do butanol, escolhidos entre dinitrato de 3-butóxi-l,2-propanodiol; dinitrato de 2-butóxi-l,3-propanodiol; e dinitrato de polietilenoglicol com massa molecular média de 200 daltons; e
• - entre 0,005 % e 3,0 % de um poliglicol que atua como co-aditivo melhorador de cetanos e como lubrificante e apresenta efeito sinérgico com o nitrato orgânico, tal como polietileno glicol de massa molecular média 2000 daltons.

[0118] Based on the research and tests carried out, the optimized formulation of this patent was obtained, which consists of the following in %v/v:

• - between 89 and 98% of a 4-carbon alcohol fuel, such as n-butanol, isobutanol, sec-butanol and tert-butanol;
• - between 0.5 and 10% of one or more nitrates capable of increasing the explosiveness of butanol, chosen from 3-butoxy-1,2-propanediol dinitrate; 2-butoxy-1,3-propanediol dinitrate; and polyethylene glycol dinitrate having an average molecular weight of 200 daltons; It is
• - between 0.005% and 3.0% of a polyglycol which acts as a cetane-improving co-additive and as a lubricant and has a synergistic effect with organic nitrate, such as polyethylene glycol of average molecular mass 2000 daltons.

[0119] It will also be convenient for the mixture to contain additional performance additives, already disclosed in patent PI 1004630-5, owned by the author of the present patent, that is, a stabilizing additive (controller of the hydrolysis of nitrates) such as: diphenylamine , diphenylureas (such as ethyl centralite), morpholine, or other compounds of a weakly alkaline character, one or more anti-corrosive additives that act by forming adsorbed film on metal surfaces, commercially available, such as: mixture based on polyether Keropur MFlex 3651, mixture based on carboxylic acid amide KeroKorr 3232, both from BASF AG, Tolad 3224 or Tolad 3222, both from Baker Hughes.

[0120] It is also evidenced by the tests to date, that other dinitrates of glycol ethers derived from glycerin, or dinitrate of polyglycols, synthesized from alcohols, can act as cetane enhancers in synergy with polyglycols, and that other polyglycols can present the same synergistic mechanism disclosed by the present patent. It is also evident that other alcohols or mixtures of alcohols can be used together with the synergistic additives of the present patent, without losing the new and surprising effect disclosed here.

Claims (1)

"RENEWABLE FUEL FORMULATION APPLIED IN DIESEL CYCLE AND BASED ON ALCOHOL", with formulation, characterized by the following composition in % v/v:

• - between 89 and 98% of a 4-carbon alcohol fuel, such as n-butanol, isobutanol, sec-butanol and tert-butanol;
• - between 0.5 and 10% of one or more nitrates capable of increasing the explosiveness of butanol, chosen from 3-butoxy-1,2-propanediol dinitrate; 2-butoxy-1,3-propanediol dinitrate; and polyethylene glycol dinitrate having an average molecular weight of 200 daltons; It is
• - between 0.005% and 3.0% of a polyglycol which acts as a cetane-improving co-additive and as a lubricant and has a synergistic effect with organic nitrate, such as polyethylene glycol of average molecular mass 2000 daltons.