Biofuel oil suspension and method for producing same

Abstract

The invention relates to a biofuel oil suspension using biochar in its composition. In this case, the present invention provides a biofuel aqueous suspension comprising 5 to 50% by weight of micronized biochar and 50 to 95% by weight of oil. The biofuel oil suspension of the present invention is better adapted to compression internal combustion engines (diesel type) in the current market without the need to significantly reform them. Furthermore, the biofuel oily suspension of the present invention has a high degree of sustainability and has an energy volume density and viscosity compared to liquid fossil fuels currently on the market.

Description

Technical Field

[0001] The present invention relates to fuels. More particularly, the present invention relates to biofuel oily suspensions using solid biochar in its composition. Background Art

[0002] Internal combustion engines are widely used in industries covering areas such as mechanical movement, combined heat and power and transportation, covering a wide range of capacities. Internal combustion engines are used in different modes of transportation, large, medium and small machines as well as in the naval, railway and road sectors. Compression combustion internal combustion engines are of great significance and are often called diesel engines in honor of their inventor, Rudolph Diesel.

[0003] Liquid fossil fuels from petroleum distillation are usually used in compression internal combustion engines. Generally speaking, for large engines, higher viscosity fuels called heavy fuel oil (HFO-Heavy Fuel Oil or HFOLS-Heavy Fuel Oil LowSulphur), commonly known as bunker oil, are used, while for medium and small engines, lower viscosity fuels called diesel and gas oil are used.

[0004] Although the above fossil fuels are currently widely used, the world is rapidly moving towards a change in the energy matrix, which will mean a bold commitment to a zero-carbon emission economy. In order to achieve the goal of reducing greenhouse gases (GHG) in the transportation sector, countries must take a series of measures at the same time. Biofuels are one of the main drivers of reducing carbon emissions in the transportation sector in several countries.

[0005] For example, the European Union (EU) recently launched a bold plan to reduce GGE emissions by at least 55% by 2030, known as the “Fit for 55” package, which will help member states achieve the goal of EU carbon neutrality by 2050 under the Paris Agreement. The plan includes the transport sector, including aviation and maritime transport, which currently account for almost 40% of all emissions. The commitment of these modes to the envisaged targets is crucial for the continent to achieve rapid reductions in CO2 emissions.

[0006] It is also proposed to ban the use of traditional diesel, gasoline, natural gas or even hybrid technology in new cars by 2035, creating space for vehicles powered by electric or biodiesel.

[0007] In this scenario that is gradually spreading across the world, biodiesel plays a very important role in providing an energy alternative to complete fossil fuels, as biodiesel usually contains raw materials of plant origin such as soybean oil, cotton, castor bean, sunflower, babassu, peanut, palm oil, etc. in its composition.

[0008] In addition to the conventional biodiesel compositions described above, recent studies have shown that it is possible to use coal, particularly coal of mineral origin, in micronized form (particle size less than 50 μm) mixed with a liquid (eg water) to form an aqueous suspension.

[0009] However, the use of micronized mineral coal to make aqueous suspensions still faces several technical barriers in practical application, as its physicochemical properties (calorific value, viscosity and inorganic content) are different from those of fuels used today, which requires modifications to engines currently on the market.

[0010] In addition, solid coal has a hydrophobic chemical property, which makes it difficult to maintain stability when mixed with water. Another related point is that experimental results show that the calorific value and energy density of water-coal suspensions are much lower than those of fuels currently on the market.

[0011] Finally, the presence of inorganic materials in the composition of the micronized carbon used in prior art biofuels often creates fouling and wear problems due to the wear of internal engine parts.

[0012] In the context of the search for sustainability of production processes, biomass pyrolysis technology has been recognized by the technical and scientific community as a powerful tool for converting biomass into new products such as charcoal, synthesis gas (syngas) and liquids such as tar and pyrowood extracts. It is precisely to characterize the biomass pyrolysis process strictly carried out in terms of operational safety and respect for the environment that charcoal began to acquire other names in the literature, such as biochar or biocarbon. The present invention will adopt the last term to represent the solid products obtained by the pyrolysis of biomass.

[0013] The present invention solves the above-mentioned prior art problems simply and effectively. Summary of the invention

[0014] A first object of the present invention is to provide an oily suspension of biofuel based on biochar that is better adapted to the compression internal combustion engines currently on the market, without requiring major modifications to them.

[0015] A second object of the present invention is to provide an oily biofuel suspension based on highly sustainable biochar having a calorific value, energy density and viscosity comparable to the fuels currently existing on the market.

[0016] In order to achieve the above object, the present invention provides a biofuel oily suspension comprising 5 to 50% by mass of micronized biochar and 50 to 95% by mass of a suspension base liquid.

[0017] The present invention also provides a method for producing the above-mentioned biofuel oily suspension, comprising the following steps: (i) micronizing biochar to a maximum diameter of 50 μm; and (ii) mixing 5% to 50% by mass of the micronized biochar with 50% to 95% by mass of a suspension base liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The detailed description given below refers to the accompanying drawings and their respective reference numerals.

[0019] Figure 1 A schematic diagram showing the interactions between various molecules surrounding biochar particles in the biofuel oily suspension of the present invention. DETAILED DESCRIPTION

[0020] First, it should be noted that the following description will start with preferred embodiments of the present invention. However, as known to those skilled in the art, the present invention is not limited to these specific embodiments.

[0021] Thus, the present invention provides an oily biofuel suspension comprising 5 to 50% by mass of micronized biochar and 50 to 95% by mass of a suspension liquid matrix. For the purposes of this specification, micronized biochar is any plant-derived charcoal with a maximum diameter of 50 μm produced according to sustainable standards. Preferably, the biochar has a low inorganic content (less than 1%).

[0022] Preferably, the liquid matrix of the above suspension is at least one of the following: (i) marine fuel oil (also known as HFO-Heavy Fuel Oil), (ii) marine diesel oil (MDO-Marine Diesel Oil or MGO-Marine Gasoi), (iii) hydrogenated vegetable oil (HVO-Hydrotreated Vegetable Oil), (iv) hydrogenated pyrolysis oil (HPO-Hydrotreated Pyrolysis Oil) and (v) vegetable tar (also known as pyrolysis oil (PO-Oil of Pyrolysis or Pyrolysis Oil)).

[0023] More preferably, the liquid matrix of the suspension used in the present invention may be a mixture of at least two of the above oils in an appropriate ratio to produce a biofuel having a viscosity and energy density comparable to fuel oil on the market.

[0024] In a first embodiment of the present invention, the following composition is used: 5 to 50 mass % micronized biochar; 50% to 95% by mass of marine fuel oil; and 0% to 30% marine diesel or gas oil.

[0025] In this first embodiment, biochar is mixed with ship fuel oil. The engineering of large internal combustion engines is already prepared to run with the typical viscosity of ship fuel oil. Naturally, as the solid biochar particles are introduced into the suspension, its viscosity tends to increase. Another oily matrix (diesel or gas oil) is then introduced to adjust the viscosity of the suspension and restore it to a value close to the original viscosity of the ship fuel oil. This is a suspension characterized by the partial replacement of fossil fuels (ship fuel oil) by green fuels (biochar). It is a suspension that is highly optimized in terms of technology (combustion) and logistics, because the introduction of biochar can be carried out in different proportions and implemented step by step.

[0026] In a second embodiment of the invention, the following composition is used in a 100% sustainable manner: 5 to 50 mass % micronized biochar; 50 to 95% by mass of hydrogenated vegetable oil; and 0% to 50% vegetable tar.

[0027] In this second embodiment, the biochar is mixed with a completely green oily matrix which can be HVO (hydrogenated vegetable oil) or vegetable tar (pyrolysis oil (PO)) or a mixture of these ingredients. The suspension is characterized by a lower viscosity compared to marine fuel oil and in this case consists only of sustainable products (ie of renewable origin).

[0028] In a third embodiment of the invention, also in a 100% sustainable manner, the following composition is used: 5 to 50 mass % micronized biochar; and 50 to 95 mass % hydrogenated pyrolysis oil.

[0029] In this third embodiment, the suspension consists of biochar and an oily matrix HPO (hydrogenated pyrolysis oil) and, like the second embodiment, is fully sustainable.

[0030] The three embodiments described above have a common feature: the use of micronized biochar in the composition. In order to minimize the degree of wear of the suspension due to wear in a diesel engine, the biochar is preferably produced from biomass with a low ash content (e.g. eucalyptus, preferably without bark, whose inorganic content is higher than the wood core itself).

[0031] The present invention also provides a method for producing the above-mentioned biofuel oily suspension, comprising the following steps: (i) micronizing biochar to a maximum diameter of 50 μm; and (ii) mixing 5% to 50% by mass of the micronized biochar with 50% to 95% by mass of a suspension liquid matrix.

[0032] The present invention relates to an oily biofuel suspension, the composition of which contains a portion of biochar from biomass carbonization in micronized form (particles less than 50 μm). The presence of biochar has ecological benefits (e.g. reduction of greenhouse gases and SO x emissions), market (lower costs through the use of cheaper fuel feedstocks), and technological advantages.

[0033] The main technical advantage comes from the catalytic effect caused by the presence of solid biochar particles in the reaction atmosphere in the engine combustion chamber. Figure 1 Schematic representations of these catalytic phenomena are shown, hinting at the molecular interactions occurring in this reaction medium.

[0034] Firstly, the internal surface area, related to the porosity, as well as the external surface area of ​​the biochar particles favour the physical adsorption processes of oxygen molecules and other liquid fuels, promoting the chemical interactions between them, which characterise the catalytic effect during the combustion process. More specifically, biochar is a product with a high carbon concentration, which is usually greater than 80%, depending on the raw materials and production operating conditions. Therefore, biochar is a fragile and porous product, while these pores can be closed or open. In relation to the degree of micronisation, the external specific surface area of ​​the particles is generated and, in relation to the porosity, the internal specific surface area of ​​the particles is generated. Both the external specific surface area and the internal specific surface area contribute to the phenomenon of heterogeneous catalysis during the combustion process. This effect is Figure 1 This is illustrated in Figure 1, where HC liquid fuel molecules interact with O2 oxygen molecules in a more significant and frequent manner, and these interactions happen to be on the inner and outer surfaces of BC biochar particles. This interaction Figure 1 Highlighted with a blue circle.

[0035] Furthermore, the catalytic effect of the injection of potassium salts in the combustion of solid, liquid and gaseous fuels is known. It is also known from the relevant literature that during the carbonization of biomass, a migration of inorganic elements present in the precursor biomass occurs, forming pockets of SiO2 and KCl crystals on the surface of the biochar particles. Biomass and its respective biochar contain micronutrients in its composition, including potassium salts. Thus, heterogeneous suspensions containing biochar are an intrinsic way to seek this catalytic effect of potassium in combustion processes. This effect (in which potassium reduces the activation energy and catalyzes the reaction of oxygen with the carbon surface of the biochar itself) is known as Figure 1shown and highlighted with an orange circle.

[0036] Optionally, the invention also provides for the introduction of additives into the biochar-based biofuel oily suspension, such as surfactants, to improve the stability of the solution and its handling, transport and storage properties. The additives may be used in small proportions, typically less than 5%.

[0037] In addition to the innovative effects listed above, the following advantages are also observed in the biofuel of the present invention: 1) The friability of biochar allows grinding to obtain particles with a typical size of less than 50 μm under relatively competitive operating cost conditions; 2) preferably, the biochar is micronized to achieve a bimodal particle size distribution, which is beneficial for preparing the oily suspension of the present invention; 3) Biochar has low ash and sulfur content compared to other carbonaceous materials (e.g., mineral coal); 4) The catalytic process associated with biochar improves the combustion properties of the suspension, thereby enhancing the performance of diesel engines; 5) The burning time of the porous biochar particles is short, typically the stroke time of many diesel cycle engines (e.g., low speed engines used in marine transportation) of interest in industrial applications of the present invention. This provides full solid fuel combustion efficiency and low levels of particulate matter emissions; 6) Catalytic optimization of the combustion process of the oil phase of the suspension and of the biochar particles themselves allows the engine to be operated at lower compression levels, resulting in a higher thermal efficiency of the engine; 7) Due to the catalytic combustion process associated with biochar particles, x Better performance in terms of atmospheric emissions of pollutants; 8) Since the biofuel oily suspension of the present invention is partially or fully renewable, it contributes to the reduction of greenhouse gas emissions in the form of CO2 into the atmosphere.

[0038] The viscosity, calorific value and energy density of the biofuel of the present invention can be adjusted according to its application. In this way, it can be adjusted to replace any type of diesel currently on the market. For example, the present invention can be used very effectively to replace marine fuel in low-speed engines (such as marine engines). However, its application is not limited to this specific application and can also be used for engines used in railway, road, air transportation, machine movement and cogeneration.

[0039] Therefore, as described above, the present invention provides a biofuel oily suspension that is better adapted to diesel engines currently on the market without requiring major modifications to them. In addition, the biofuel oily suspension of the present invention is highly sustainable and has a calorific value, energy density and viscosity comparable to fuels currently on the market.

[0040] Various changes that affect the scope of the invention are permissible. Thus, it is further indicated that the invention is not limited to the specific configurations / embodiments described above.

Claims

1. A biofuel oily suspension, characterized in that: Include: 5 to 50 mass % micronized biochar; and 50% to 95% by mass of liquid suspension base.

2. The biofuel oily suspension according to claim 1, characterized in that: The liquid matrix of the suspension is at least one of: Ship fuel; Marine diesel or gas oil; Hydrogenated vegetable oils; Hydrogenated pyrolysis oil; and Vegetable tar.

3. The biofuel oily suspension according to claim 2, characterized in that: The liquid matrix of the suspension is a suspension of at least two of: Ship fuel; Marine diesel; Hydrogenated vegetable oils; Hydrogenated pyrolysis oil; and Vegetable tar.

4. The biofuel oily suspension according to claim 2 or 3, characterized in that: Include: 5 to 50 mass % micronized biochar; 50% to 95% by mass of marine fuel oil; and 0% to 30% marine diesel.

5. The biofuel oily suspension according to claim 2 or 3, characterized in that: Include: 5 to 50 mass % micronized biochar; 50 to 95% by mass of hydrogenated vegetable oil; and 0% to 50% vegetable tar.

6. The biofuel oily suspension according to claim 2 or 3, characterized in that: Include: 5 to 50 mass % of micronized charcoal; and 50 to 95 mass % hydrogenated pyrolysis oil.

7. A method for producing a biofuel oily suspension, characterized in that: The following steps are involved: The biochar was micronized to a maximum diameter of 50 μm; 5 to 50 mass % of the micronized biochar is mixed with 50 to 95 mass % of the liquid suspension matrix.

8. The method according to claim 7, characterized in that The biochar has a bimodal particle size distribution.

9. The method according to claim 7 or 8, characterized in that: The liquid matrix of the suspension is at least one of: Ship fuel; Marine diesel; Hydrogenated vegetable oils; Hydrogenated pyrolysis oil; and Vegetable tar.

10. The method according to claim 9, characterized in that The liquid matrix of the suspension is at least two of the following: Ship fuel; Marine diesel; Hydrogenated vegetable oils; Hydrogenated pyrolysis oil; and Vegetable tar.

11. The method according to any one of claims 7 to 10, characterized in that The method further comprises the step of adding at least one surfactant additive to the biofuel oily suspension.

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