Process for blending liquid fossil heavy an light fuel with liquid renewable fuel, system to carried out the process, fuel obtained and use in marine applications

Abstract

The present invention describes a process using an ultrasonic system to obtain blends of fuels with lower environmental impact and better ignition quality. This process is particularly suitable for applications in the maritime sector, using a combination of classic fossil fuels (such as heavy fuel oil or marine gas oil) that are already widely used, as well as renewable fuels such as biodiesel and hydrogenated vegetable oil.

Description

[0001] DESCRIPTION

[0002] “PROCESS FOR BLENDING LIQUID FOSSIL HEAVY AN LIGHT FUEL WITH LIQUID RENEWABLE FUEL, SYSTEM TO CARRIED OUT THE PROCESS, FUEL OBTAINED AND USE IN MARINE APPLICATIONS”

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to a process for emulsifying liquid fossil heavy fuel with liquid renewable fuel. The fuel obtained is useful as alternative fuels in shipping. The object of the process is to obtain a fuel with less toxic emissions compared to traditional carbon-based fossil fuels.

[0005] BACKGROUND OF THE INVENTION

[0006] Despite the constant global research and development of alternative energy sources, fossil fuels (which may range from coal to oil-based fuels) remain the main and most widely used source due to their availability, proven high efficiency and relatively low prices. The application of such fuels in the maritime sector is quite common, with large main engines and auxiliary generators suitably manufactured to burn them.

[0007] One issue that has caused concern over the years is the impact that burning this type of fuel has on the environment, particularly in terms of its carbon footprint (CO2) and the emission of harmful greenhouse gases such as NOx, SOx and Particulate Matter.

[0008] Fuels for use in the maritime sector have considerably high sulphur contents and their burning is restricted in certain controlled emission zones (EGA and SEGA zones). Since 1 January 2020, the International Maritime Organisation (IMO) has imposed stricter limits on the sulphur content of fuels being traded and burned. The limit for sulphur in fuel oil used in ships operating outside designated emission control areas will be 0.50 % wt / wt (weight / weight), whereas its burning as well as marine gas oil in controlled areas as well as in port is much lower (0.10 % wt / wt). In addition to the above, both marine gas oil and fuel oil have a high impact in terms of CO2 emitted. For each tonne of fuel oil burned, 3.114 tonnes of CO2 are emitted, while for each tonne of marine gas oil consumed, 3.206 tonnes of CO2 are emitted. This type of fuel emits high rates of NOx.

[0009] Given the tighter regulations that have been put in place in the international maritime sector, such as the directives presented in MEPC 79 (Marine Environment Protection Committee) and the application in 2024 of the tight emissions control regime ETS (Emissions Trading Systems), it is increasingly urgent to obtain new solutions in terms of the fuels used.

[0010] In MEPC 79, very specific targets were set for decarbonisation by 2050, with the proposed use of biofuels and a control and extension of the spectrum of controlled greenhouse gases (CH4 and nitrous oxides in addition to CO2).

[0011] Biodiesel is a greener fuel with less environmental impact and can be obtained from plant sources. Burning these fuels results in lower CO2 emissions, lower NOx and SOx emissions, and can also represent an economic advantage for existing fleets. In 2024, a new system of carbon allowances will come into force, with each shipowner having to pay for each tonne they consume in excess of their usual maximum ceiling.

[0012] Patent US10563132B2 refers to a process for reducing contaminants in heavy marine fuel oil by ultrasonic action in a multi-step process. The process consists of a desulphurisation reaction leading to minimal change in product properties (comply with ISO 8217 specifications). With this process the sulphur content is removed to admissible values between 0.05% (m / m) and 1.0% (m / m). The above-mentioned process also considers blending the feedstock with activated gas and catalysts to reduce environmental contaminants. It does, however, lead to the production of by-products such as C1-C4 light hydrocarbons and naphtha. Liquid and gaseous by-products are removed from the process. The process referred to does not involve blending with other types of fuels (such as biodiesel), nor does it mention the removal of other contaminants such as CO2 or NOx. It does, however, mention the added value of using ultrasound to remove S content from marine fuels.

[0013] The ultrasonic technique has also been used to remove sulphur from diesel fuel in order to obtain a fuel with lower environmental impact US7758745B2. Again, there is no mention of blending with other fuels such as biodiesel, nor of application for marine purposes.

[0014] According to patent US7458998B2, a method for in-line blending of biodiesel and diesel in cold environments (temperatures below 20°F) is described. This process aims to overcome limitations where the temperature of the diesel is not lower than the cloud point of the biodiesel. Fuels especially those with long hydrocarbon chains are very sensitive to temperature and tend to crystallise. This blending, however, does not use ultrasound and is blended by conventional mechanical systems.

[0015] Other blending processes are referred to in the patent application US 20050160663A1 , which describes a system for blending biodiesel and diesel to produce a cleaner burning end product. The process considers the use of a catalyst (fuel borne catalyst-FBC) containing platinum and / or cerium or iron. The limit of the process restricts the results obtained to only 20% incorporation of biodiesel. Ultrasound is not used in this blend.

[0016] The applicants of patent US11518950B2, describe a process in which two types of biodiesel (one between 12-15 wt%), a diesel and an additive are blended in order to obtain a final product with a cetane number between 45 and 70, leading to a better burning product with less particulates. The process is silent on how the blending is carried out, with final emissions tested in a constant volume flow system (CVS).

[0017] From all that has been said, it can be seen that it is still important to develop new fuels that can overcome the limitations of the fuels of the state of the art and that can be used as marine fuels that emit fewer toxic gases into the atmosphere.

[0018] SUMMARY OF THE INVENTION

[0019] The present invention overcome the problems viewed in the state of the art and development a fuel with a lower emission of toxic gases than the fossil fuels used, and without the problem that show the biodiesel fuels as tendencies to oxidise in tanks, affinity to water and sediment formation. It would be possible to incorporate a significant percentage of biodiesel into the base formulation of the fossil fuel, maintain its performance and reduce the impact of its combustion. The fact that biodiesel fuels are blended with commonly used fuels will allow to minimise some of their most harmful effects in terms of storage and use.

[0020] The in-line blending of the fuels is carried out in two subsequent steps. In a first step the different fuels are mixed, where a pre-mixing of the fuels takes place. Subsequently, the stream containing the fossil fuel and biodiesel is re-routed to a step of sonicating the mixture. By the effect of the application of ultrasound, at a frequency between 20kHz to 24 kHz, a homogenisation of the fuels in a single phase is established. This application has the advantage of breaking the hydrocarbon chains. At the same time, it reduces impurities present in the fuel, such as sediments, asphaltenes or ashes, which leads to more efficient combustion. The present invention describes a process using an ultrasonic system to obtain fuels with lower environmental impact and better ignition quality, resulting in lower emissions.

[0021] The contact time in the cavitation chamber will depend on the specific consumption required by the engine. The final fuel is then fed to the engine, leading to a final product that complies with the different permissible specifications for marine fuels, according to ISO 8217. The output current from the cavitation chamber is conducted to the combustion engine and is not subjected to a storage process.

[0022] The fuel produced in this process also has the advantage that the combustion process is similar, requiring few modifications to the engines currently used on board ships for the most diverse applications, transport of goods or passengers, also known as “drop in” fuels.

[0023] Therefore, the first aspect of the invention refers to a process for blending liquid fossil marine fuel with liquid renewable fuel comprising the step: a) mixing the liquid fossil marine fuel with the liquid renewable fuel to obtain a mixture; b) sonicating the mixture obtained in the step a) by the application of ultrasound, at a frequency between 20kHz to 24 kHz to obtain an in-line fuel blend; d) transporting the blend to a combustion engine.

[0024] The system to carried out the process referred of the first aspect of the invention comprises a static mixer and an ultrasonic unit named ultrasonic-induced cavitation chamber (UIC). The ratio of the different fuels is established on the basis of two Coriolis flow meters. Therefore, the second aspect of the invention refers to a system to carried out the process of the invention comprising: a) segregated storage tanks, one for the liquid fossil marine fuels and a second for the liquid renewable fuel; b) one Coriolis flowmeter after the liquid fossil marine fuel storage tank and a second Coriolis flowmeter after the liquid removable fuel tank, to control the quantity required of each fuel; c) a static mixer wherein the fuels are pre mixed; d) an ultrasonic induced cavitation chamber wherein the mixed fuels are emulsified; e) an engine wherein the fuel is fed.

[0025] Another aspect of the invention is the fuel obtainable by the process of the invention.

[0026] Also, it is an aspect the fuel blend consisting of: a liquid fossil marine fuel and a liquid renewable fuel; the blend shows: a viscosity between 80% and 95% lower than the weighted media of the initial viscosity of the fossil marine heavy fuel and a liquid renewable fuel, metered according to the ISO standard 3104; a sulphur content between 10% and 50%, lower than the weighted media of the initial viscosity of the fossil marine heavy fuel and a liquid renewable fuel; metered by the X- ray fluorescence technique-ASTM D4294.

[0027] The viscosity and sulphur content meters does no makes part of the system.

[0028] The fuel fulfils the specifications of ISO 8217 standard for marine fuels, also the blend is very stable. The blend of the invention complies with the fuel specifications for different grades: DMX, DMB, DMZ and DMA in the case of blending between liquid renewable fuel and liquid fossil marine fuels. In the same way the blend of the present invention complies with the fuel oil specifications for different grades: RMA (Residual Marine Fuel Grade A), RMB (Residual Marine Fuel Grade B), RMD (Residual Marine Fuel Grade D), RME(Residual Marine Fuel Grade E) , RMG(Residual Marine Fuel Grade G) and RMK(Residual Marine Fuel Grade K) which are defined in terms of properties by the Standard ISO 8217. Finally, it is an aspect of the invention the use of the heavy fuel of the invention in maritime transport.

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] For the purpose of aiding the understanding of the characteristics of the invention, according to a preferred practical embodiment thereof and in order to complement this description, the following figures are attached as an integral part thereof, having an illustrative and non-limiting character:

[0031] Figure 1 shows a schematic of a realisation of the system according the second aspect of the invention.

[0032] DETAILED DESCRIPTION OF THE INVENTION

[0033] As it described above the first aspect of the invention refers to a process for blending liquid fossil marine fuel with liquid renewable fuel comprising the step: a) mixing the liquid fossil marine heavy fuel with the liquid renewable fuel to obtain a mixture; b) sonicating the mixture obtained in the step a) by the application of ultrasound, at a frequency between 20kHz to 24 kHz to obtain a blend; d) transporting the blend to a combustion engine.

[0034] Preferably the liquid fossil marine fuel is selected from: marine gas oil (MGO) and heavy fuel oil (HFO). Particularly the liquid renewable fuel is biodiesel, i.e. fatty acid methyl ester from vegetable cooking oils vegetable oils, or hydrogenated vegetable oils. For biodiesel, the percentage of biomass-sourced fuel is indicated with the prefix B, such as B7, B10, B20, and where B100 indicates an unblended pure biodiesel liquid which can provide the maximum carbon reduction option for users.

[0035] Preferably the process comprises a step of preheating of the liquid fossil marine heavy fuels and / or the liquid renewable fuels before the step a) which is conducted at a temperature between 30 and 95°C. This step is useful in order to lower the heavy fuel oil viscosity and to improve the mixture. MGO, Biodiesel and Hydrogenated vegetable oil do not need any heating as they have very low viscosity at ambient temperature, although Heavy Fuel Oil needs heating

[0036] Preferably the step b) is carried out at a temperature is in a range from 57°C to 107°C in order to keep the fuels at low viscosity.

[0037] Preferably in the step a) the liquid renewable fuels in the mixture are in the range from 10% to 50% referred to weight / total weight of the mixture.

[0038] The quality of the final product, the fuel can be analysed and if the contact time in the cavitation chamber was not sufficient to obtain the desired density (confirmed in the Coriolis flow meter), it is returned to contact with the ultrasonic system. Therefore, preferably after the step b) and before the step d), there is a step c) of analysing the density of the blend of step b) and if the density it is not the desired returning the blend to step b).

[0039] As said, the second aspect of the invention refers to a system to carried out the process of the invention comprising: a) segregated storage tanks, one for the liquid fossil marine fuels (1) and a second for the liquid renewable fuels (2); b) a first Coriolis flowmeter (4) localized after the liquid fossil marine fuel storage tank

[0040] (1) and a second Coriolis flowmeter (3) localized after the liquid removable fuel tank

[0041] (2), to control the quantity required of each fuel; c) a static mixer (5) wherein the fuels are pre mixed; d) ultrasonic induced cavitation chamber (6) wherein the mixed fuels are blended; e) an engine (7) wherein the fuel blend is fed.

[0042] The dosing of the fuels is carried out by means of the supply pumps, the proportion being controlled on the basis of valves and the flow value indicated by the flowmeter.

[0043] Therefore, preferably the system also comprises a first pump (8) and a first valve (9) localized between the first Coriolis flowmeter (4) and the static mixer (5); a second pump (10) and a second valve (11) localized between the second Coriolis flowmeter (3) and the static mixer (5). More preferably the system further comprises a third pump (12) localized between the static mixer (5) and the ultrasonic induced cavitation chamber (6). Preferably the system further comprises a third Coriolis flowmeter (13), a fourth pump (14) and a third valve (15) situated in this order between the ultrasonic induced cavitation chamber (6) and the engine (7).

[0044] Finally, the last aspect of the invention refers to a fuel blend consisting of: a liquid fossil marine heavy fuels and a liquid renewable fuel wherein the blend shows: a viscosity between 80% and 95% lower than the weighted media of the initial viscosity of the fossil marine fuel and a liquid renewable fuel, metered according to the ISO standard 3104; a sulphur content between 10% and 50%, lower than the weighted media of the initial sulphur content of the fossil marine fuel and a liquid renewable fuel; metered by the X- ray fluorescence technique-ASTM D4292.

[0045] An advantage of the product is that when the resulting fuels blend of the invention undergoes a combustion process the emission of CO2, NOXSOXand Particulate Matter are lower than the combustion of the neat marine fuels before being subjected to the process of the invention. The reduction of CO2 emissions is 40% in , 30% in terms of NOX, metered by Elemental analysis- ASTM D5291.

[0046] A toxic gases like SO2 or SO3 is a direct proportional to the percentage of sulphur content of the heavy fuel oil, by producing a blend with “x%” of B100, the result on the blend would be “x%” reduced to the original content, therefore a reduction of “x%” will be obtained.

[0047] Also, considering that the B100 to be used is originated from used cooking oil (circular economy), then its CO2 has been compensated and is certified by ISCC International Sustainability and Carbon Certification, and carbon index is issued 14.9gCO2eq / MJ which is a lot less that the carbon index of heavy fuel oil.

[0048] Another advantage is the improvement in the ignition quality of the final product obtained (CCAI (Calculated Carbon Aromaticity Index-Value) and an increase in the lower calorific power between 1.5 and 2.5% referred to the fuels prior to be undergoes to the process of the invention, resulting in lower fuel consumption and therefore contributing for the lower CO2 emissions.

[0049] Preferably the content of liquid renewable fuels in the blend is in the range from 10% to 50% referred to weight / total weight.

Claims

CLAIMS1. A process for in line blending of liquid fossil marine fuels with liquid renewable fuel characterizing by comprising the step: a) mixing the liquid fossil marine fuel with the liquid renewable fuel to obtain a mixture; b) sonicating the mixture obtained in the step a) by the application of ultrasound, at a frequency between 20kHz to 24 kHz to obtain a blend; d) transporting the blend to a combustion engine.

2. The process according to the claim 1 characterized by further comprises a step of preheating the liquid fossil marine fuel and / or the liquid renewable fuel before the step a) which is conducted at a temperature between 30 and 95°C.

3. The process according to any of the preceding claims 1 to 2, characterized by the step b) is carried out at a temperature is in a range from 57eC to 107°C.

4. The process according to any of the preceding claims 1 to 3, characterized by the liquid fossil marine fuel is selected from: marine gas oil (MGO) and heavy fuel oil (HFO) and the liquid renewable fuel is biodiesel or hydrogenated vegetable oil.

5. The process according to claim 4 characterized by the biodiesel is fatty acid methyl ester from vegetable oils.

6. The process according to any of the preceding claims 1 to 5, characterized by in the step a) the liquid renewable fuels in the mixture are in the range from 10% to 50% referred to weight / total weight of the mixture.

7. The process according to any of the preceding claims 1 to 5, characterized by after the step b) and before the step d), the process further comprises a step c) of analysing the density of the blend of step b) and if the density it is not the desired returning the blend to step b).

8. A system to carried out the process of the invention defined according to claim 1 to 7 comprising:a) segregated storage tanks, one for the liquid fossil marine fuels (1 ) and a second for the liquid renewable fuels (2); b) a first coriolis flowmeter (4) localized after the liquid fossil marine fuel storage tank(1) and a second coriolis flowmeter (3) localized after the liquid removable fuel tank(2), to control the quantity required of each fuel; c) a static mixer (5) wherein the fuels are mixed; . d) ultrasonic induced cavitation chamber (6) wherein the mixed fuels are emulsified; e) an engine (7) wherein the fuel blend is fed.

9. The system according claim 8 characterized by further comprises a first pump (8) and a first valve (9) localised between the first Coriolis flowmeter (4) and the static mixer (5); a second pump (10) and a second valve (11 ) localized between the second Coriolis flowmeter(3) and the static mixer (5); a third pump (12) localized between the static mixer (5) and the ultrasonic induced cavitation chamber (6); and a third coriolis flowmeter (13), a fourth pump (14) and a third valve (15) situated in this order between the ultrasonic induced cavitation chamber (6) and the engine (7).

10. A fuel blend obtainable by the process defined in the claims 1 to 7.11 . A fuel blending consisting of: a liquid fossil marine fuel and a liquid renewable fuel; the blending shows: a viscosity between 80% and 95% lower than the weighted media of the initial viscosity of the fossil marine fuel and a liquid renewable fuel, metered according to the ISO standard 3104; a sulphur content between 10% and 50%, lower than the weighted media of the initial viscosity of the fossil marine fuel and a liquid renewable fuel; metered by the X-ray fluorescence technique-ASTM D4294.

12. The fuel blend according claim 11 characterized by the liquid renewable fuels is in the range from 10% to 50% referred to weight / total weight of the the liquid fossil marine fuel and a liquid renewable fuel.

13. Use of the fuel according to any of the claims 10 to 12 in maritime transport.

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