WO2015174870A1

WO2015174870A1 - Production of fuels from microbial glycolipids with lipid chains comprising 6 to 14 carbons

Info

Publication number: WO2015174870A1
Application number: PCT/PT2015/000020
Authority: WO
Inventors: Frederico Castelo Alves FERREIRA; Nuno Ricardo FARIA; César Simões da FONSECA
Original assignee: Instituto Superior Técnico; Laboratório Nacional De Energia E Geologia
Priority date: 2014-05-15
Filing date: 2015-05-14
Publication date: 2015-11-19
Also published as: PT107637A

Abstract

The present invention relates to the process of production of liquid fuel for air, marine or land transportation from microbial glycolipids with lipid chains composed only of 6 to 14 carbons. This process is characterized by the. conversion of microbial glycolipids into a mixture, of organic compounds through glycolipid chemical transes.terification with an alcohol into esters having 7 to 16 carbons and mixtures thereof, or conversion of the glycolipid in hydrocarbons having 4 to 14 carbons. The organic compounds obtained by these processes are to be used as fuel, as such, or in blends with other substances, for air, marine or land transportation, including but not limited to transportation at temperatures below zero degrees Celsius.

Description

DESCRIPTION

PRODUCTION OF FUELS FROM MICROBIAL GLYCOLIPIDS WITH LIPID CHAINS

COMPRISING 6 TO 14 CARBONS

Field of the invention The present invention relates to the process of production of liquid fuel for air, marine or land transportation, from -microbial glycolipids with lipid chains comprising only 6 to 14 carbons. This process is characterized by the conversion of microbial glycolipid into a mixture of organic compounds through its chemical transesterification with an alcohol, namely methanol, ethanoi , propanol, propanol or butanoi into esters having 7 to 16 carbons and mixtures thereof, or converting into hydrocarbons composed only of 4 to 14 carbons.

The organic compounds obtained by this process can be used as fuel, as such, or in blends with other fuels, resulting in aviation fuels with freezing point below forty degrees Celsius and heating value above forty Megaj oules per kilogram (1,2) or i fuels for marine or land transportation resulting in fuel with freezing points below zero degrees Celsius.

State of the art

Global climate changes, apparently associated to increasing greenhouse gases emissions, and the issues, raised by increasing fuel prices and security of supply, have resulted in a transition of fossil fuels to more sustainable and renewable energy sources . For land transportation there is an effort to develop alternative- energy sources, such as bioethanoi , biodiesel or the use of electricity to power cars, trucks and railways systems. However, for the aviation industry, the use of such solutions is not possible. The heating value supplied from batteries, fuel cells or bioethanoi is not appropriate. The fuel obtained through biological pathways, such as biodiesel obtained from vegetable or animal oils have melting points equal, to, or higher than zero degrees Celsius, such is the case of biodiesel obtained from vegetable or animal oils which cannot be used ,for aviation (2) .

The "jet fuel'' is a type of specialized fuel derived from crude fossil oil, which requires freezing point below forty degrees Celsius and heating value higher than forty Megajoules per kilogram (1,2), allowing the fuel to stay in the liquid state at temperatures experimented during the flight and also providing enough energy to maintain flight autonomy and loading capacity suitable for commercial use. Conventionally, f els Used in aviation are from fossil source, kerosene, rich in hydrocarbons having between 10 to 16 carbons per molecule, aromatics and naphther.es (1) . Fuel specifications for aviation required to ensure compliance with efficiency and safety are summarized in the following table (1) .

Table 1. Specification of aviation, fuel.

Properties Specification

0.775 - 0.840 Kg/I

Density

(15°C)

Flash point > 38°C

Freezing point < -40°C

Heating value > 42.8 MJ/kg

Boiling point 200-300°C

Viscosity <8 cSt (.-20°C) The processes suggested for production of aviation fuel from, biological sources involve a process of production of synthetic gas from biomass followed by liquefaction of such gas through the Fischer-Tropsch reaction (4) or, alternatively, a catalytic fractioning and hydrogenation of biomass, including vegetable oils or long chai animal oils, into hydrocarbons with suitable sizes (5) . These are processes that imply the breaking of carbon-carbon bonds, being energy intensive processes and therefore their effectiveness is inherently limited.

Also in land transportation in. cold climates, such as the polar regions (including major portion of the United States of America, Canada, the Nordic countries and northern Asia) , where biodiesel tends to solidify restricting its use in engines, the use of such biofuels are not^' efficient alternative solutions to replace fossil fuel.

There is an unmet need in the current state of the art for the development of formulations containing biofuels that do not solidify at low temperatures and that comply with the fuel specifications for marine or land transportation at low temperatures and aviation. Fuels that remain liquid below zero degrees (C, D, E, F according to standard EN 590) are for the purposes of this invention designated as "winter diesel".

Several microbial species have the ability of producing glycolipids lipid chains composed only of 6 to 14 carbons linked to sugars through ester linkages, inherently labile (6) .

In the literature several methods for the chemical transesterification of esters with an alcohol into the respective alcohol ester are reported (7), namely using an acid, for example sulphuric acid, or a n alkaline base, for example methoxide and ethoxide or sodium or potassium hydroxide, as catalyst. Transesterification reactions can also be catalyzed by enzymes such as lipases (8). Taking into account how easy is to break ester bonds, the catalytic reaction of esters with hydrogen results in the formation of hydrocarbons (3) . The most oils found in plants and animals comprise 16 or 18 chain carbons. Thus,, the respective biodiesel obtained from such oils has a freezing point near zero degrees Celsius, posing problems to its use in land and marine transportation in regions with colder winters. The solutions suggested include reducing the fraction at which such biofuel is blended with diesel (fossil) or the use . of additives. The use of alcohol esters with shorter chains addresses effectively this problem ( 1 ) .

Summary of the invention The present invention relates to a process of production of liquid fuel for air, marine or land transportation from microbial glycolipids with lipid chains composed only of 6 to 14 carbons. This process is characterized by the conversion of microbial glycolipid into a mixture of organic compounds through chemical transesterification with an alcohol into esters chains having between 7 to 16 carbons and mixtures thereof, or conversion into hydrocarbon chains having between 4 to 14 carbons . The glycolipid ester bond is broken by transesterification processes or catalytic reaction with hydrogen being obtained organic compounds such as esters or hydrocarbons having a number of carbon atoms per molecule from 7 to 16 and 4 to 14 carbons, respectively. In one embodiment, organic compounds obtained from the conversion of microbial glycolipids, ester chains having between 7 to 16 carbons, or hydrocarbon chains having between 4 to 14 carbons are used as such, for use in winter diesel for land transportation and marine transportation.

The term "such as" should be understood, in the present invention, as a way of using the said organic compounds without being blended with fossil fuels.

In another embodiment, the organic compounds obtained from the conversion of microbial glycolipids, esters chains having between 7 to 16 carbons, or hydrocarbons having chains between 4 to 14 carbons, are used in blends with fossil fuels for use in aviation fuel. or as winter diesel for marine or land transportation .

Mixtures of esters with chains of 7 to 16 carbons may be blended up to 20% (v/v) with fossil fuels for use in liquid aviation fuel.

Mixtures of hydrocarbons with chains of 4 to 14 carbons may be blended up to 50% (v/v). with fossil fuels for use in liquid aviation fuel.

The fuel obtained has a low freezing point and a high heating value, suitable for use in air, marine or land transportation, at temperatures below zero degrees Celsius.

Detailed description of the invention

The present invention relates to a process of production of liquid fuel for aviation, land, and marine transportation from microbial glycolipids with lioid chains composed only of 6 to 14 carbons. This process is characterized by the conversion of microbial glycolipids into a mixture of organic compounds through glycolipid chemical transesterification with an alcohol into esters having between 7 to 16 carbons and mixtures thereof or into hydrocarbons having between 4 to 14 carbons.

The fuel composition obtained through the present invention can be prepared starting from microbial glycolipids. The microbial glycolipids. used can be obtained from vegetable, animal or microbial oils, lignocellulosic compounds, sugars or alcohols, and converted into a formulation of hydrocarbon or alcohol esters suitable for use in aviation or in climate with low temperatures.

The size of the lipid chains of microbial glycolipids, lower than the one found in vegetable oils used for bio.diesel production, provides a unique opportunity for production of fuels that combine a high heating value and a low freezing point. Examples of glycolipids lipid chains with 6 to 14 carbons are rhamholipids and mannosylerythritol lipids.

The glycolipid ester bond is broken by acid, alkaline or enzymatic transesterification processes or by a catalytic reaction with hydrogen, resulting, respectively, esters having between 7 to 16 carbons or hydrocarbons having between 6 to 14 carbons. As. esters bonds are notably labile, these reactions have lower energetic requirements, making this a more efficient process than those proposed previously, in particular Fischer- Tropseh or long-chain oils cracking methods. The esters or hydrocarbon molecules obtained from glycolipids are separated from the sugar f action, and used for production of a fuel formulation of low freezing point and high heating value. Aviation fuels may be obtained by mixing the molecules of esters or hydrocarbons produced from microbial glycolipids, up to 50% with other certificated aviation fuels, namely, but not exclusively, with Jet A or Jet Al fuel resulting in a freezing point lower than forty degrees Celsius and heating value higher than forty Megajoules per kilogram.

The fuels for marine or land transportation at temperatures preferably, but not exclusively, below zero degrees Celsius are obtained using esters and hydrocarbons obtained from glycolipids, as such, or in blends with, · including but hot limited, fossil or biological origin diesel, resulting in a fuel with freezing point below zero degrees Celsius. In one embodiment, organic compounds obtained from the conversion of microbial glycolipids, ester chains having between 7 to 16 carbons or hydrocarbon chains having between 4 to 14 carbons, are used as such as a fuel for marine or land transportation.

In another embodiment, the organic compounds obtained from the conversion of microbial glycolipids, ester chains having between 7 to 16 carbons or hydrocarbon chains having between 4 to 14 carbons are used in blends with fossil fuels for aviatio fuel or as winter diesel for marine or land transportation.

Mixtures of esters with chains of 7 to 16 carbons may be blended up to 20% (v/v) with fossil fuels fox use in liquid aviation fuel.

Mixtures of hydrocarbons with chains of 4 to 14 carbons may be blended up to 50% (v/v) with fossil fuels for use in liquid aviation fuel.. The fuel obtained has a low freezing point and a high heating value suitable for use in aviation, marine or land transportation at temperatures below zero degrees Celsius. The freezing point of hydrocarbons and alkanes is directly proportional to the length of their carbon chains, and the lower- freezing points are obtained for shorter chains. However, the combustion energy of these molecules decreases as their carbon chains size decreases. The lipid chains of the glycolipids used for the microbial production of these fuels composed only of 6 to 14 carbons long, presents the ideal size for production of winter diesel or aviation fuel that comply with the respective specifications. Lipid units and the glycoside unit of the glycolipid are Govalently linked by ester bonds, which are relatively labile, facilitating their breaking in terms of energy and reaction.

Examples

For a better understanding of the invention, by way of illustration and not limitation, ^' examples of application of the present invention are described below.

It is expected to obtain the same product in chemical transesterifications using other alcohol examples, such as ethanol, butanol, propanol, etc., since chemical reaction mechanisms are identical for these alcohols, through the alcohol group and not significantly affected by alkyl groups of these molecules. Example 1

Production of methyl esters having 7 to 15 carbons obtained by alkaline transesterification of glycolipids with lipid chains between 6 and 14 carbons with methanol. 0.5 g of mannosylerythritol lipids were added to 0.4 g of sodium methoxide in 1 ml of methanol, and heated at 50°C for 6 hours under stirring. The resulting reaction mixture was subjected to extraction with water and hexane (in the ratio 1:1) at room temperature, resulting in the organic phase, a mixture composed by a mixture of methyl esters with the composition 10% methyl octanoate, 45% methyl decanoate and 45% methyl dodecanoate. The aqueous phase was discarded. The yield of the reaction was 50- 60%. This yield was calculated as the ratio of moles of methyl esters per mole of lipid chains existing in the glycolipid subjected to reaction, where 100% corresponds to a reaction in which the substrate is completely converted.

Example 2

Production of methyl esters having 7 to 15 carbons obtained by acid transesteri.fication of glycolipids with lipid chains having between 6 and 14 carbons with methanol. Mannosylerythritol lipids (0.5 g) were added to 0.1 mM sulphuric acid in 3 ml of methanol and heated at 80°C for 6 hours under stirring. The resulting reaction mixture was subjected to extraction with water and hexane at room temperature, resulting in the organic phase, a mixture of methyl esters composed by 10% methyl octanoate, 45% methyl decanoate, 45% methyl dodecanoate. The aqueous phase was discarded. The reaction yield was greater than 95%. This yield was calculated as the ratio of moles of methyl esters per mole of lipid chains existing in the glycolipid subjected to reaction, where 100% corresponds to a reaction in which the substrate is comoletelv converted. Example 3

Production of hydrocarbons having 7 to 15 carbons obtained by catalytic reaction of g.lycolipids with lipid chains having between 6 to 14 carbons, with gaseous hydrogen. Mannosylerythritol lipids (0.5 g) were placed in a metal vessel with, a catalyst usually used in the field, previously activated by dimethyl sulphide heated at 350 °C and pressurized to 50 bar for 6 hours. The resulting reaction mixture was subjected to extraction with water and hexane at room temperature, with the organic phase containing a mixture of alkanes composed of 10% octane, 45% decane and 45% dodecane. The aqueous phase was discarded. The yield of the reaction was 50-60%. The reaction yield was calculated as the ratio of moles of hydrocarbon per mole of lipid chains in the existing glycolipid subjected to reaction, where 100% corresponds to a reaction in which the substrate is completely converted.

Example 4

Blends of 10, 20 and 50 and 100% v/v methyl esters mixtures having 7 to 15 carbons with Jet A were prepared and their freezing point, heating value, flash point, viscosity and density of the blends were quantified.. Table 2 provides the properties of blends of aviation fuel with the biofuel molecules produced by transesterification . Freezing temperature below - 40°C, flash point above 47°C and heating value higher than 44 egajoules per kilogram were obtained for blends with esters containing up to 20% of Jet A. The values for viscosity measured at -20 °C were lower than .5 cSt and the values for density measured at 15°C, were between 0.775 and 0.840 kg/m³. Table 2: Values obtained for different blends of methyl esters mixtures and fossil aviation fuel.

*Methyl esters mixtures obtained. from transesterification processes described in examples 1 and 2.

Example 5

Blends of 10, 20 and 50 and 100% v/v hydrocarbons having 4 to 14 carbons with Jet A were prepared and their freezing point, density, flash point, viscosity and heating value were quantified. Table 3 provides the properties of. aviation fuel blends of Jet A with the biofuel molecules produced by catalytic reaction with hydrogen. Freezing temperatures below -44 °C, flash point above 44°C and heating value higher than 46 Mega joules per kilogram were obtained for blends containing up to 50% of hydrocarbon mixtures. The values for viscosity measured at -20 °C were lower than 2.5 cSt and the values for density measured at 15⁶C were between 0.775 and 0.840 kg/m³.

Table 3: Values obtained for different blends of alkanes mixtures with fossil aviation fuel.

*Alkanes mixtures obtained from hydrogenation proce described in example 3.

Example 6 Blends of 10, 20, 30, 50 and 100% v/v methyl esters having 7 to 15 carbons with diesel were prepared and their freezing point, heating value, flash point, viscosity and density of the blends were quantified. Table 4 provides the properties of the fuel blend of the fuel molecules produced by transesterification with commercial diesel. Freezing temperatures of -6.2 up to -7.8°C (blends between 10 to 50%) were obtained for blends containing up to 50% of hydrocarbon mixtures. When used at 100%, the produced methyl ester molecules have a freezing point of -20°C.

Table 4: Values obtained for different combinations of blends of methyl esters with diesel.

*Methyl esters mixtures obtained

processes described in examples 1 and

Example 7

Blends of 10, 20, 30, 50, and 100% v/v hydrocarbons having 4 to 14 carbons with diesel were prepared, and their freezing point, heating value,, flash, point, viscosity and density blends were quantified. Table 5 provides the properties of fuel blends of the fuel molecules produced by catalytic reaction with hydrogen with commercial diesel. Freezing temperatures of -7.0 up to - 13.2°C (blends between 10 to 50%) were obtained for blends containing up to 50% of produced hydrocarbons with diesel. When used at 100%, the hydrocarbon molecules produced in example 2 have a freezing point of -30.9°Ο. Table 5: Values obtained for different blends of alkanes mixtures with diesel.

Blends Freezing point

(°C)

- Diesel -5.9

(loo%)

Alkanes* (10%) Diesel -7.0

(90%)

Alkanes* (20%) Diesel -8.1

(80%)

Alkanes* (70%) Diesel -9.8

(30%)

Alkanes* (50%) Diesel -13.2

(50%)

Alkanes* (100%) - -30.9

*Alkanes mixtures obtained from hydrogenation processes described in example 3.

References

1. Milton, B World Jet Fuel Specifications with Avgas Supplement. (2005). t http : //www . exxonmobil . com/AviationGlobal/Files/WorldJetFuel Specifications2005. pdf .

2. Hemighaus, G. et al. Alternative Jet Fuels: A supplement to cheyron's aviation fuels technical review. Cheyron Corporation (2006) .

3. Aatola, H., Larmi, M. , Sarjovaara, T. & Mikkonen, S.

Hydrotreated vegetable oil (HVQ) as a renewable diesel fuel: trade-off between NOx, particulate emission, and fuel consumption of a heavy duty engine. Helsinki University of Technology & Neste Oil, Finland (2008) . 4. Leckel, D. Diesel Production from Fischer-Tropsch : The Past, the Present, and New Concepts. Energy & Fuels 23, 2342-2358 (2009.)

5. Tiwari, R . et al. Hydrotreating and hydrocracking catalysts for processing of waste soya-oil and_. refinery-oil mixtures. Catalysis Communications 12, 559-562 (2011)_..

6. Morita T, Konishi M, Fukuoka T, Imura T, Kitamoto HK, Characterization of the genus Pseudozyma by the formation of glycolipid biosurfactants , mannosyleryth itol lipids.

FEMS Yeast Research. 34 : 286-292 (2007).

7. Srivastava, A. & Prasad., R. Triglycerides-based diesel fuels. Renewable and Sustainable Energy Reviews 4, 1.11.-133 (2002) .

8. Ranganathan, S.V., Narasimhan, S.L. & Muthukumar, K. An overview of enzymatic production of biodiesel. Bioresource Technology. 99, 3975-3981 (2008).

May 13^tn, 2015

Claims

1. Production of liquid fuel, for aviation and winter diesel for land and marine transportation, using blends of organic compounds mixtures with chains having 4 to 16 carbons, characterized in that the fuel is obtained through a chemical reaction from microbial glycolipids with lipid chains composed only of 6 to 14 carbons..

2. Production of fuel according to Claim 1, characterized in that the microbial glycolipids are mannosylerythritol lipids or rhamnolipids .

3. Production of fuel according to Claims 1 and 2, characterized in that microbial glycolipids are obtained from vegetable or animal oils, lignocellulosic materials, sugars or alcohols.

4. Production of fuel, according to the previous claims, characterized in that the blend of organic compounds comprises hydrocarbon mixtures having 4 to 14 carbons or esters mixtures having 7 to 16 carbons.

5. Production of fuel according to the previous claims, characterized in that the hydrocarbon mixtures having 4 to 14 carbon chains are produced from microbial glycolipids through the catalytic reaction of hydrogen with the said microbial glycolipid.

6. Production of fuel, according to claims 1 to 4, characterized in that the esters mixtures having 7 to 16 carbons are produced from microbial glycolipids through chemical transesterification of a microbial glycolipid with an alcohol..

7 . Production of fuel, according to the previous claims, characterized in that the esters mixtures or the hydrocarbons mixtures, produced from microbial glycolipids, are used as such, or blended with fossil diesel.

8. Production of fuel, according to claims. 1 to 5, characterized i that the hydrocarbons mixtures produced from microbial glycolipids are blended up to 50% (v/v) with aviation liquid fuels from fossil origin.

9. Production of fuel, according to claims 1 to 4 and 6, characterized in that the esters mixtures produced from microbial glycolipids are blended up to 20% (v/v) with aviation liquid fuels from fossil origin.

10. Use of the fuel as defined in claims 1 to 6 and 8 to 9, characterized in that the liquid fuel is employed in liquid fuel fox aviation.

11. Use of fuel as defined in claims 1 to 7 , characterized in that the fuel is employed in winter diesel for marine or land transportation.