Selection of Blends of Diesel Fuel and Advanced Biofuels Based on Their Physical and Thermochemical Properties

energies

Article Selection of Blends of Diesel Fuel and Advanced Biofuels Based on Their Physical and Thermochemical Properties

José Rodríguez-Fernández * , Juan José Hernández , Alejandro Calle-Asensio, Ángel Ramos and Javier Barba Universidad de Castilla-La Mancha, Escuela Técnica Superior de Ingenieros Industriales, Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain; [email protected] (J.J.H.); [email protected] (A.C.-A.); [email protected] (Á.R.); [email protected] (J.B.) * Correspondence: [email protected]; Tel.: +34-926-295300 (Ext. 6472) Received: 9 May 2019; Accepted: 23 May 2019; Published: 28 May 2019 Abstract: Current policies focus on encouraging the use of renewable energy sources in transport to reduce the contribution of this sector to global warming and air pollution. In the short-term, attention is focused on developing renewable fuels. Among them, the so-called advanced biofuels, including non-crop and waste-based biofuels, possess important benefits such as higher greenhouse gas (GHG) emission savings and the capacity not to compete with food markets. Recently, European institutions have agreed on specific targets for the new Renewable Energy Directive (2018/2001), including 14% of renewable energy in rail and road transport by 2030. To achieve this, advanced biofuels will be double-counted, and their contribution must be at least 3.5% in 2030 (with a phase-in calendar from 2020). In this work, the fuel properties of blends of regular diesel fuel with four advanced biofuels derived from different sources and production processes are examined. These biofuels are (1) biobutanol produced by microbial ABE fermentation from renewable material, (2) HVO (hydrotreated vegetable oil) derived from hydrogenation of non-edible oils, (3) biodiesel from waste free fatty acids originated in the oil refining industry, and (4) a novel biofuel that combines fatty acid methyl esters (FAME) and glycerol formal esters (FAGE), which contributes to a decrease in the excess of glycerol from current biodiesel plants. Blending ratios include 5, 10, 15, and 20% (% vol.) of biofuel, covering the range expected for biofuels in future years. Pure fuels and some higher ratios are considered as well to complete and discuss the tendencies. In the case of biodiesel and FAME/FAGE blends in diesel, ratios up to 20% meet all requirements set in current fuel quality standards. Larger blending ratios are possible for HVO blends if HVO is additivated to lubricity improvers. For biobutanol blends, the recommended blending ratio is limited to 10% or lower to avoid high water content and low cetane number.

Keywords: advanced biofuels; diesel blends; fuel properties; quality standards

1. Introduction Increasing the renewable energy fraction in transport is an urgent necessity to tackle global warming and air pollution. Recent pollution episodes in big cities have prompted the adoption of local and regional policies that will progressively (from the present to 2040–2050) ban internal combustion vehicles. Electricity from renewable sources will be decisive to achieve and maintain a fully sustainable mobility system as it has been analyzed in detail elsewhere [1], but the short-and-mid-term attention must be focused on developing renewable and sustainable fuels, especially those with a more beneﬁcial carbon balance [2]. Advanced biofuels, including some non-crop and waste-based biofuels, possess important beneﬁts such as higher GHG emission savings and the capacity not to strain food markets [3]. European

Energies 2019, 12, 2034; doi:10.3390/en12112034 www.mdpi.com/journal/energies Energies 2019, 12, 2034 2 of 13 institutions agreed to specific targets that have been set in a new Renewable Energy Directive (2018/2001) [4] published in December 2018, including 14% of renewable energy in rail and road transport by 2030. To achieve this, advanced biofuels will be double-counted, and their contribution must be at least 3.5% in 2030 (with a phase-in calendar from 2020). Moreover, crop-derived biofuels will be capped at levels achieved in 2020 and not higher than 7% whereas raw materials with a high risk of ILUC (indirect land-use change) must be fully abandoned by 2030. In the case of diesel fuels, the pool of advanced biofuels is still wide. Alcohol-diesel blends, if the alcohol comes from lignocellulosic wastes, biodiesel fuels derived from residual oleaginous materials and/or paraffinic fuels such as BTL (Biomass-To-Liquid) or HVO (Hydrotreated Vegetable Oil) can be considered advanced biofuels. So far, biodiesel fuels are the most studied but also the most controversial biofuels. The final product consists on a mix of a few fatty acid methyl esters (FAME); therefore, the fuel properties vary within narrow ranges around values generally close to those exhibited by conventional fossil diesel fuels. But the reduction of lifecycle GHG emissions of biodiesel fuels depends largely on the origin of the raw vegetable oil/animal fat. Even some biodiesel origins have been reported to increase GHG emissions [5]. Two approaches, both treated in the present work, are gaining attention as a means to ensure a beneficial lifecycle GHG emission balance: (i) biodiesel fuels partially or totally derived from other industrial wastes and (ii) biodiesel routes that reduce the production of low valued byproducts (such as low-grade glycerol). The esterification of residual free fatty acids recovered from the palm oil industry is a way of dealing with a very abundant waste coming from the palm oil industry [6]. Some works have been focused on the reactions involved in the production process and the selection of catalysts [7,8], whereas properties and engine emissions have not received much attention although they are expected to depend on the purity and quality of the final methyl ester product. In the second approach, esters of glycerol formal (FAGE) yielded from waste oils and glycerol as reagents have been proved as a reliable option. However, the high viscosity and poor cold flow properties of FAGE [9] make desirable to blend FAGE and FAME to obtain a renewable biofuel with properties suitable for diesel applications. The reactions needed for both, FAGE and FAME, may be implemented jointly in current biodiesel plants thus making the whole process more economic. When used in diesel engines, benefits in carbon monoxide, hydrocarbons and particulate matter were found and supported based on their oxygen content [10]. Alcohol-diesel blends are reported to reduce particle and other emissions mainly because of their oxygen content. Ethanol is the most conventional alcohol [11–13] used for blending, but n-butanol has some advantages over ethanol, such as higher heating value, higher cetane number and better miscibility with diesel [14,15]. Recently, chemical and biological processes to produce n-butanol from renewable and waste sources have gained attention [16]. Among them, bacterial fermentation may reduce greenhouse emissions on a life-cycle basis [17] and, thus, is a promising technique [18,19]. Highly paraffinic fuels such as gas-to-liquid (GTL), biomass-to-liquid (BTL) and hydrotreated vegetable oil (HVO) have emerged as alternative diesel fuels with some outstanding diesel properties (mainly cetane number and heating values) that offer potential to reduce fuel consumption, and thus CO2 emissions, and harmful emissions of diesel vehicles [20]. Moreover, these fuels have been claimed to be fully compatible with current engine technologies. HVO has the best economic perspectives since the chemical process may be integrated in current oil refineries [21,22], using the existing reactors and hydrogen streams. HVO production technology removes the O-atoms and the double bonds of the raw material through a process called hydrotreating catalysis. The raw material is the same than in the case of biodiesel, but the chemical route and the final product are different. Many works have examined and compared both fuels, and even ternary blends (diesel-biodiesel-HVO) have been proposed to exploit the advantages of both biofuels. The selection of fuels and blends should not be made ignoring the properties of the final blends. A correct blending proportion based on the property’s ranges set in current fuel quality standards may guarantee the absence of vehicle failures, such as those episodes encountered at some places Energies 2019, 12, 2034 3 of 13 when using certain biodiesel blends in cold ambient conditions. Besides, many of the fuel properties directly affect the engine-out emissions [23]. The current European legislative framework imposes that any final diesel fuel (neat or blended) to be used in road transport must meet all the EN 590 requirements; besides, biodiesel and paraffinic fuels must fulfill, before blending in regular diesel, the additional requirements set in EN 14214 for biodiesel and EN 15940 for paraffinic fuels. In this frame, the present work examines the main fuel properties of feasible blends of four advanced biofuels in regular fossil diesel fuel and proposes ranges and target values for each biofuel. The selected blends will be tested in a diesel engine and/or vehicle, in a different study, to check whether the suggested blending proportions work as expected under real driving conditions.

2. Materials and Methods

Density was measured at 15 ◦C according to EN 3675 introducing an appropriate densimeter into the flask that contain the fuel tested. The flask is surrounded by water in a thermostatic bath from Fisher Scientific (Tamson TV 2000, with a temperature control precision of 0.1 K). Kinematic ± viscosity was measured using Cannon-Fenske viscometers introduced in the same bath. In this case, the temperature of the water during the viscosity tests was maintained at 40 ◦C, according to standard EN ISO 3104. Higher heating value (HHV) analysis was conducted according to standard ASTM D4809, using a Parr 6100 calorimetric bomb. Lower heating value (LHV) was also calculated from the HHV value and the elemental analysis, which was carried out using a Carlo Erba EA1108 analyzer. Lubricity was carried out according to EN 12156-1 in a high frequency reciprocating rig (HFRR) from PCS Instruments. The wear scar was measured with an Optika SZR1 microscope equipped with a 100x magnification lens. All lubricity tests were made inside a climatic chamber (provided by PCS Instruments) where the ambient temperature and humidity were controlled according to the limits set in EN 12156-1:2016 with the use of a potassium carbonate solution. The Cold Filter Plugging Point (CFPP) and the Cloud Point (CP), representative of cold flow properties, were measured according to the standards EN 116/ASTM D6371 for CFPP and EN 23015/ASTM D2500 for CP. The device used to measure the CFPP was PACFPP 5Gs whereas the instrument used for measuring CP was PAC-CPP 5Gs. Derived Cetane Number (DCN) was measured in the equipment Cetane ID510 by Herzog. This equipment consists of a constant-volume combustion chamber (0.473 L) and a common-rail diesel injector (operating at 1000 bar injection pressure) similar to those used in commercial engines (Bosch part no 0445110181) with 6 nozzles with orifice diameter of 0.17 mm. Synthetic air (21% O2 and 79% N2 v/v) was used as oxidant and the initial absolute pressure was kept constant at 21 bar. In every test, 15 fuel injections for each fuel were carried out. DCN is determined through the ignition and combustion delays according to ASTM D7668, both calculated from the pressure signal. Finally, water content measurement was carried out by using Karl-Fischer 831 KF according to EN 12937.

3. Fuels and Blends The reference diesel fuel of this work was supplied by Repsol S.A. This fuel meets all requirements in the European Standard EN 590. Unlike commercial fuels available in ﬁlling stations, this fossil fuel does not contain biodiesel or HVO; thus, it can be used for blending with the biofuels evaluated here. Four advanced biofuels were selected:

an HVO fuel, donated by NESTE, produced from camelina and other waste vegetable oils; • biobutanol supplied by Green Biologics and produced from bacterial fermentation; • a biodiesel fuel supplied by Masol Iberia Biofuel, which is composed of fatty acid methyl esters • (FAME). Instead of producing this fuel through a conventional transesteriﬁcation reaction using vegetable oil and methanol as reagents, it was derived from waste fatty acids recovered from the palm oil industry and transformed into methyl esters by an esteriﬁcation reaction; Energies 2019, 12, x 2034 FOR PEER REVIEW 4 4of of 13 13

• a target blend of 70% FAME (±1%), 27% fatty acid glycerol formal esters—FAGE (±1%) and 3% acetalsa target (±0.2%), blend of produced 70% FAME and ( supplied1%), 27% by fatty Inkemi acida-IUCT glycerol (this formal blend esters—FAGE is commercially ( 1%) known and 3%as • ± ± o.bio®).acetals ( The0.2%), FAME produced fraction and was supplied produced by Inkemia-IUCTfrom waste cooking (this blend oil and is commerciallywas used as reagent known to as ± produceo.bio®). the The FAGE FAME through fraction transesterification-transk was produced from wasteetalization cooking reactions. oil and Acetals was used were as reagentyielded as to by-productsproduce the FAGEin these through reactions. transesterification-transketalization reactions. Acetals were yielded as by-products in these reactions. For all four biofuels, biofuel-diesel blends at blending ratios of 5, 10, 15 and 20% (in volume basis)For were all fourprepared biofuels, and biofuel-diesel tested. To gain blends accura at blendingcy in the ratios targeted of 5, 10, blending 15 and 20% ratios, (in volume appropriate basis) laboratorywere prepared glassware and tested. material To gainwas employed accuracy in(volum the targetedetric flasks blending and pipettes). ratios, appropriate The volumes laboratory of both componentsglassware material were measured was employed separately (volumetric prior to flasks blending. and pipettes).Considering The the volumes present of and both the components proposals forwere future measured standards, separately low-content prior to blends blending. such Consideringas those evaluated the present here are and the the most proposals interesting. for future For completeness,standards, low-content the properties blends of such dies asel thosefuel and evaluated the neat here biofuels are the were most also interesting. measured, For and completeness, in the case ofthe biodiesel properties and of HVO, diesel blends fuel and at the30 neatand 50% biofuels were were included also measured, as well (these and intwo the biofuels case of biodieselshow no incompatibilityand HVO, blends with at current 30 and 50%diesel were engines included and 30 as and well 50% (these blends two are biofuels typically show used no in incompatibility captive fleets andwith in current other demonstration diesel engines andprograms). 30 and 50%Biobutanol-diesel blends are typically blends usedat higher in captive biobutanol fleets content and in otherthan 20%demonstration were not tested programs). as they have Biobutanol-diesel no interest in blendsthe diesel at higherfuel market biobutanol and they content could thanshow 20% blending were stabilitynot tested problems as they haveat low no temperature interest in the or diesel with fuelwater market contamination. and they could The values show blending of all measured stability propertiesproblems atare low tabulated temperature in Appendix or with waterA. contamination. The values of all measured properties are tabulated in AppendixA. 4. Results and Discussion 4. Results and Discussion 4.1. Density 4.1. Density Figure 1 presents the density of all the blends and neat fuels tested. Each blend/fuel was tested Figure1 presents the density of all the blends and neat fuels tested. Each blend /fuel was tested three times and the average value is displayed in the figure. None of the replicated measurements three times and the average value is displayed in the figure. None of the replicated measurements deviated more than 2 kg/m3 from the average value. Fuel dispensers in filling stations operate in deviated more than 2 kg/m3 from the average value. Fuel dispensers in filling stations operate in volume volume units. In diesel vehicles, electronic injection adjusts the fuel mass introduced into the units. In diesel vehicles, electronic injection adjusts the fuel mass introduced into the combustion combustion chamber by modifying the injection time (i.e. the volume of fuel) and assuming a chamber by modifying the injection time (i.e., the volume of fuel) and assuming a standard density standard density set in the ECU cartography. In view of these, fuel quality standards impose a narrow set in the ECU cartography. In view of these, fuel quality standards impose a narrow density range, density range, as suggested elsewhere [24]. In the case of EN 590, density is specified at 820‒845 as suggested elsewhere [24]. In the case of EN 590, density is specified at 820–845 kg/m3. kg/m3. 920

900 Biodiesel HVO BioButanol 880 o.bio ) 3 860

840

820 Density (kg/m 800

780

760 0 102030405060708090100 Biofuel content (%v/v) Figure 1. DensityDensity of of fuels fuels and and blends. blends.

ComparedCompared to the density of diesel fuel (biofuel content = 0%),0%), blends blends with with biodiesel biodiesel (FAMEs) (FAMEs) or or ® o.bio®o.bio (FAMEs and FAGEs, mainly) increase density, while blends with HVO or butanol have the oppositeopposite effect. eﬀect. The The density density of of biobutanol biobutanol is is closer closer to to that that of of diesel diesel than than that that of of ethanol (ethanol was notnot tested tested here, here, but but it itis isthe the most most common common alcohol alcohol used used for fordiesel diesel blending blending despite despite its miscibility its miscibility and hygroscopicand hygroscopic problems), problems), which which is one is oneof ofthe the adva advantagesntages of ofbiobutanol biobutanol blending blending over over ethanol. ethanol. Considering the importance of limiting the variations of density, it would be possible to design a

Energies 2019, 12, 2034 5 of 13

ConsideringEnergies 2019, 12 the, x FOR importance PEER REVIEW of limiting the variations of density, it would be possible to design a5 diesel of 13 blend with a selected composition of two of the biofuels here tested (biodiesel and HVO, for example, sincediesel theblend production with a selected processes compos of bothitionbiofuels of two of have the biofuels been suggested here tested to be(biodiesel combined and in HVO, a single for plantexample, [22]) since obtaining the production a ternary blendprocesses which of keepsboth bi theofuels density have at been the same suggested value thanto be diesel’s. combined in a singleAs plant expected, [22]) obtaining the trend a of ternary the density blend is which quite linearkeeps withthe density the blend at the composition, same value which than diesel’s. indicates that thereAs expected, is no change the trend of volume of the density on mixing is quite (or lin it isear negligible). with the blend Therefore, composition, the density which of indicates a blend atthat any there other is no composition change of thanvolume tested on mixing here could (or it be is calculatednegligible). with Therefore, minor errorthe density by multiplying of a blend the at densityany other of composition the two components than tested by thehere volume could fractions;be calculated this canwith be minor extended error to by blends multiplying with more the thandensity two of components. the two components In order toby fulfill the volume the required fractions; regulated this can density be extended range, theto blends content with of biofuel more cannotthan two exceed components. 20% (it could In order be higher to fulfill in the the case requir of butanoled regulated blends, density though range, in this the case content high biobutanol of biofuel contentscannot exceed are not 20% debated (it could in the be diesel higher fuel in market). the case of butanol blends, though in this case high biobutanol contents are not debated in the diesel fuel market). 4.2. Lower Heating Value 4.2. Lower Heating Value The heating value of a fuel indicates its energy content per unit mass (MJ/kg) or volume (MJ/L). EachThe blend heating/fuel wasvalue tested of a fuel three indicates times, andits energy the average content deviation per unit mass was 0.10(MJ/kg) MJ/ kgor volume (the maximum (MJ/L). diEachfference blend/fuel between was replications tested three was times, 0.40 MJand/kg). the Althoughaverage deviation the instruments was 0.10 used MJ/kg to perform (the maximum heating valuedifference measurements between replications usually provide was 0.40 mass MJ/kg). units, Although volume units the instruments are preferred used in theto perform transport heating sector becausevalue measurements of the reasons usually outlined provide previously mass (densityunits, vo section).lume units are preferred in the transport sector becauseAlthough of the reasons this property outlined is not previously currently (density limited in section). diesel quality standards, its effect is meaningful. LowAlthough values lead this to higher property fuel consumptionis not currently and alimite loss ofd engine in diesel power quality at full load.standards, In modern its effect vehicles, is themeaningful. lean NOx Low trap values (LNT) purginglead to higher and the fuel Diesel consumption Particle Filter and (DPF) a loss regeneration of engine power are accomplished at full load. byIn post-injectingmodern vehicles, fuel the to increaselean NOx exhaust trap (LNT) temperature. purging and The the volume Diesel and Particle timing Filter of these (DPF) post-injections regeneration are setaccomplished in the electronic by post-injecting control unit (ECU)fuel to byincrea these manufacturer exhaust temperature. engine calibration The volume department. and timing But of if thethese heating post-injections value of the are fuel set used in the by aelectronic user during control real driving unit (ECU) is not highby the enough, manufacturer it may derive engine in acalibration lower exhaust department. temperature But if than the neededheating and,value therefore, of the fuel in unsuccessfulused by a user or during incomplete real driving regenerations is not andhigh eventuallyenough, it vehicle may failurederive [25in, 26a ].lower exhaust temperature than needed and, therefore, in unsuccessful or incomplete regenerations and eventually vehicle failure [25,26].

45.0 36.0

42.5 33.5 40.0

37.5 31.0

Biodiesel Biodiesel 35.0 HVO HVO BioButanol 28.5 BioButanol o.bio o.bio

32.5 Lower Heating Value (MJ/L) Lower Heating Lower Heating (MJ/kg) Value

30.0 26.0 0 102030405060708090100 0 102030405060708090100 Biofuel content (%v/v) Biofuel content (%v/v)

Figure 2. Lower heating value of fuels and blends, in mass units ( left) and volume units (right).

As in the case of density, thethe heating values of the blends tested changes quite linearly with the blend composition (Figure2 2).). ThisThis confirms,confirms, togethertogether withwith thethe nilnil changechange ofof volumevolume onon mixing,mixing, thatthat these fuel blends blends can can be be treated treated as as ideal ideal mixtures mixtures.. The The lower lower heating heating value value of of HVO HVO in inmass mass units units is ishigher higher than than that that of ofthe the diesel diesel fuel; fuel; on on the the contrary, contrary, in in volume volume units, units, it it is is lower. lower. This This trend can be extrapolated to all paraparaffinicffinic fuels (HVO, XTL), sinc sincee paraffins paraffins in the C-range typical of diesel fuels usually display highhigh heatingheating valuesvalues in in mass mass units units but but lower lower densities densities than than other other hydrocarbons hydrocarbons (such (such as aromatics).as aromatics). Nevertheless, Nevertheless, the the loss loss of volumetricof volumetric heating heating value value of HVOof HVO compared compared to diesel to diesel is only is only 3%; therefore,3%; therefore, this propertythis property does notdoes hinder not hinder the use the of use neat of HVO neat in HVO vehicles in vehicles with no with (or just no minor)(or just changes minor) inchanges the engine in the calibration. engine calibration. The opposite The case opposite is biobutanol, case whichis biobutanol, heating value which is unassuminglyheating value low. is unassumingly low. The content of biobutanol in diesel blends should be limited around 10% if admissible loss of heating value is to be set at 3%. About o.bio® and biodiesel fuels, the heating values of both are close to each other, especially when given in volume units, as their components are quite similar (ester-based). Compared to diesel,

Energies 2019, 12, 2034 6 of 13

The content of biobutanol in diesel blends should be limited around 10% if admissible loss of heating value is to be set at 3%. About o.bio® and biodiesel fuels, the heating values of both are close to each other, especially Energies 2019, 12, x FOR PEER REVIEW 6 of 13 when given in volume units, as their components are quite similar (ester-based). Compared to diesel, ® thethe heating heating value value of of neat neat o.bio® o.bio andand biodiesel biodiesel is is approximately approximately 10% 10% lower, lower, in in volume volume units, units, thus thus the the recommendedrecommended content content in in diesel diesel blend should not be higher than 30%. 4.3. Lubricity 4.3. Lubricity Fuel lubricity is essential in the injection system as it reduces wear and scuffing between parts Fuel lubricity is essential in the injection system as it reduces wear and scuffing between parts in relative motion [27], such as in the interior of diesel fuel pumps and fuel injectors. The concern in relative motion [27], such as in the interior of diesel fuel pumps and fuel injectors. The concern about fuel lubricity has increased over the years due to the sulphur removal in the fuel (the process about fuel lubricity has increased over the years due to the sulphur removal in the fuel (the process used in oil refineries for this task eliminates natural lubricant hydrocarbons) and the lower mechanical used in oil refineries for this task eliminates natural lubricant hydrocarbons) and the lower tolerances allowed in injection system components. mechanical tolerances allowed in injection system components. Each fuel/blend was replicated twice, being the average deviation between replications lower Each fuel/blend was replicated twice, being the average deviation between replications lower than 10 µm, which is below the maximum deviation admitted in the test standard EN 12156-1:2016 than 10 μm, which is below the maximum deviation admitted in the test standard EN 12156-1:2016 (50 µm maximum in one case out of twenty). (50 μm maximum in one case out of twenty). Figure3 presents the lubricity of the fuels and blends of this work. Neat diesel and HVO are Figure 3 presents the lubricity of the fuels and blends of this work. Neat diesel and HVO are commercial fuels, additivated with lubricity enhancers by the fuel manufacturers to fulfill the limit commercial fuels, additivated with lubricity enhancers by the fuel manufacturers to fulfill the limit (lower than 460 µm) set in EN 590 (for automotive diesel fuels) and EN 15940 (for paraffinic fuels). (lower than 460 μm) set in EN 590 (for automotive diesel fuels) and EN 15940 (for paraffinic fuels). The highest wear scar diameter (i.e., poorest lubricity) was found for biobutanol, though this alcohol The highest wear scar diameter (i.e. poorest lubricity) was found for biobutanol, though this alcohol is better lubricant than ethanol [15]. The biobutanol tested has no lubricant additive as it was used is better lubricant than ethanol [15]. The biobutanol tested has no lubricant additive as it was used as as received from the chemical supplier. Both ester-based fuels, biodiesel, and o.bio®, exhibited the received from the chemical supplier. Both ester-based fuels, biodiesel, and o.bio®, exhibited the best best lubricity. The ester functionality present in FAME (biodiesel) molecules can be adsorbed on lubricity. The ester functionality present in FAME (biodiesel) molecules can be adsorbed on metal metal surfaces while the rest of the chain (long aliphatic chain) creates a film that prevents wear. surfaces while the rest of the chain (long aliphatic chain) creates a film that prevents wear. The The extremely good lubricant properties of biodiesel have been proved previously [28,29], but the extremely good lubricant properties of biodiesel have been proved previously [28,29], but the results results here presented confirm now the same result for FAGE/FAME blends. here presented confirm now the same result for FAGE/FAME blends. 600 Biodiesel 550 HVO 500 BioButanol o.bio 450 400 350 300 250 Wear scar dialmieter (μm) dialmieter scar Wear 200 150 0 102030405060708090100 Biofuel content (%v/v) FigureFigure 3. 3. WearWear scar scar diameter diameter (lubrici (lubricity)ty) of of fuels fuels and and blends. blends.

TheThe lubricity lubricity of of the the blends blends did did not not change change linearly linearly with with the the blend blend composition. composition. In the In thecase case of the of ester-basedthe ester-based biofuels, biofuels, the thelubricity lubricity improved improved strongly strongly with with the the addition addition of of low low biofuel biofuel content content into into dieseldiesel until until reaching reaching a a “saturation” “saturation” level. level. From From this, this, no no further further lubricity lubricity gain gain was was manifested manifested even even at at ® higherhigher biofuel biofuel concentrat concentrations.ions. Comparing Comparing both both biofuels, biofuels, o.bio® o.bio (FAGE/FAME(FAGE/FAME blend) blend) was was the the most most promisingpromising one since only 10% was needed to ac achievehieve the maximum reduction of the wear scar. InIn the the case case of of biobutanol biobutanol and and HVO HVO blends blends in in di diesel,esel, the lubricity deteriorated with with the the biofuel biofuel contentcontent and and the the lubricity lubricity loss loss was was more significant signiﬁcant in the low content range (0–10%).(0‒10%). Low Low biofuel biofuel contentcontent is is the the most most likely likely future future scenario scenario in in the the fu fuelel market; market; therefore, therefore, this this finding ﬁnding must must be be observed observed carefully by all involved agents. For example, in case the lubricity of the reference diesel fuel used for blending was too close to the permitted value, even blends with biobutanol or HVO at 10% or lower could lead to blends out of the lubricity specification. All blends HVO/diesel tested fulfill the maximum limit set in quality standards, but the results in Figure 3 evidence some synergistic interaction between both fuels that results in poorer lubricant capacity for 30 and 50% blends than for any of the two neat fuels. As both fuels were additivated in

Energies 2019, 12, x FOR PEER REVIEW 7 of 13 origin to enhance lubricity, this result could be a consequence of some incompatibility between both additives.

4.4. Kinematic Viscosity Inside the combustion chamber, fuel viscosity affects the fuel jet features, fuel atomization and fuel-air mixing thus affecting combustion process and emissions. Outside the chamber, viscosity has effects on the injection system. Unlike other properties, neither too high nor too low values are desirable. Very high viscosity can reduce fuel flow rate and even damage the fuel pump. Very low viscosity increases leakages in the injection system, which is aggravated at increased ambient temperatures.Energies 2019, 12, 2034Fuel quality standards are aware of these issues and fix a valid viscosity range: 27‒ of4.5 13 cSt in EN 590 and EN 15940, and 3.5‒5 cSt in EN 14214 (since methyl esters in biodiesel are more viscouscarefully substances). by all involved agents. For example, in case the lubricity of the reference diesel fuel used for blendingIn the was present too close work, to the each permitted sample value, was evenmeasured blends three with times, biobutanol and orthe HVO deviation at 10% between or lower replicationscould lead to never blends exceeded out of the0.02 lubricity cSt. The specification.viscosity values are illustrated in Figure 4. The neat biofuels rankedAll as blends follows: HVO biobutanol/diesel tested showed fulfill the the lowest maximum value; followed limit set inby quality HVO, which standards, viscosity but thewas results close toin that Figure of diesel3 evidence fuel; and some biodiese synergisticl and interactiono.bio® finally, between the latter both with fuels the that highest results value. in poorer Glycerol lubricant esters (FAGE)capacity are for characterized 30 and 50% blends by higher than viscosities for any of thethan two methyl neat fuels.esters As(FAME); both fuelstherefore, were additivatedif FAGE is blendedin origin in to FAME enhance as in lubricity, the present this resulto.bio® could fuel and be a the consequence final FAGE/FAME of some incompatibilityblend is desired betweento meet theboth current additives. biodiesel standard, a low viscosity FAME is preferred to enlarge the feasible FAGE content window. 4.4. KinematicThe viscosity Viscosity of the biofuel/diesel blends changed non-linearly with the composition; in general, when any of the biofuels examined is blended in diesel, the viscosity of the least viscous fuel prevails Inside the combustion chamber, fuel viscosity affects the fuel jet features, fuel atomization and in the blend. This makes the viscosity of the blends to be lower than expected if this property were fuel-air mixing thus affecting combustion process and emissions. Outside the chamber, viscosity has linear with composition. All biofuel/diesel blends fall in the permitted viscosity range, but the effects on the injection system. Unlike other properties, neither too high nor too low values are desirable. viscosity of all the blends (especially at up to 20% HVO) is clearly lower than those of neat diesel or Very high viscosity can reduce fuel flow rate and even damage the fuel pump. Very low viscosity HVO. Once more, if the viscosity of any of these two neat fuels was closer to the minimum limit, a increases leakages in the injection system, which is aggravated at increased ambient temperatures. blend could exhibit lower viscosity than allowed in the standards. Biodiesel/diesel and o.bio® /diesel Fuel quality standards are aware of these issues and fix a valid viscosity range: 2–4.5 cSt in EN 590 and blends up to 20% do not change substantially the viscosity of the diesel fuel (a slight decrease is EN 15940, and 3.5–5 cSt in EN 14214 (since methyl esters in biodiesel are more viscous substances). observed for biodiesel, at has been reported elsewhere [30]); therefore, this blending range is In the present work, each sample was measured three times, and the deviation between replications recommended. never exceeded 0.02 cSt. The viscosity values are illustrated in Figure4. The neat biofuels ranked as Finally, viscosity and lubricity in fuel are often associated in discussions (the higher the viscosity, follows: biobutanol showed the lowest value; followed by HVO, which viscosity was close to that of the better the lubricity). Comparing Figure 3 and Figure 4, it is obvious that better lubricity is not diesel fuel; and biodiesel and o.bio® finally, the latter with the highest value. Glycerol esters (FAGE) necessarily expected in a blend with higher viscosity. Indeed, the HFRR test used to evaluate lubricity are characterized by higher viscosities than methyl esters (FAME); therefore, if FAGE is blended in works in the boundary lubrication region [31], where the friction coefficient is not dependent on the FAME as in the present o.bio® fuel and the final FAGE/FAME blend is desired to meet the current fluid viscosity as demonstrated in basic rheology [32] (unlike the hydrodynamic lubrication region, biodiesel standard, a low viscosity FAME is preferred to enlarge the feasible FAGE content window. where a liquid film separates the parts in relative motion and fluid viscosity plays a role). 6.5 6.0 Biodiesel 5.5 HVO BioButanol 5.0 o.bio 4.5 4.0

Viscosity (cSt) 3.5 3.0 2.5 2.0 0 102030405060708090100 Biofuel content (%v/v) Figure 4. Kinematic viscosity of fuels and blends Figure 4. Kinematic viscosity of fuels and blends

The viscosity of the biofuel/diesel blends changed non-linearly with the composition; in general, when any of the biofuels examined is blended in diesel, the viscosity of the least viscous fuel prevails in the blend. This makes the viscosity of the blends to be lower than expected if this property were linear with composition. All biofuel/diesel blends fall in the permitted viscosity range, but the viscosity of all the blends (especially at up to 20% HVO) is clearly lower than those of neat diesel or HVO. Once more, if the viscosity of any of these two neat fuels was closer to the minimum limit, a blend could exhibit lower viscosity than allowed in the standards. Biodiesel/diesel and o.bio® /diesel blends up to 20% do not change substantially the viscosity of the diesel fuel (a slight decrease is observed for biodiesel, at has been reported elsewhere [30]); therefore, this blending range is recommended. Energies 2019, 12, 2034 8 of 13

Finally, viscosity and lubricity in fuel are often associated in discussions (the higher the viscosity, the better the lubricity). Comparing Figures3 and4, it is obvious that better lubricity is not necessarily expected in a blend with higher viscosity. Indeed, the HFRR test used to evaluate lubricity works in the boundary lubrication region [31], where the friction coefficient is not dependent on the fluid viscosity as demonstrated in basic rheology [32] (unlike the hydrodynamic lubrication region, where a liquid film separates the parts in relative motion and fluid viscosity plays a role). Energies 2019, 12, x FOR PEER REVIEW 8 of 13 4.5. Cold Flow Properties 4.5. Cold Flow Properties Assuring enough fuel fluidity is necessary to move the fuel along the supply system (passing throughAssuring the filter enough/s) and fuel preventing fluidity is irregular necessary idling to move and startabilitythe fuel along problems. the supply Cold system flow properties (passing arethrough a hot the issue filter/s) at present and preventing as there have irregular been idling some recentand startability episodes problems. related to Cold insuffi flowcient properties values even are thougha hot issue the at fuels present involved as there did have meet been the some requirements recent episodes in the in-forcerelated to standards. insufficient The values suspicions even though point outthe towardsfuels involved some minordid meet components the requirements (saturated in monoglycerides, the in-force standards. sterol glucosides, The suspicions soaps) presentpoint out in thetowards biodiesel some fraction minor components of current automotive (saturated fuels. monoglycerides, sterol glucosides, soaps) present in the biodieselIn this fraction work, of the current measured automotive properties fuels. were cloud point—CP (temperature at which some of the fuel componentsIn this work, start the measured to crystallize) properties and cold were filter cloud plugging point—CP point—CFPP (temperature (temperature at which atsome which of the fuel doescomponents not pass start through to crystalliz a filtere) in and a required cold filter time, plugging under standardizedpoint—CFPP instrument(temperature and at which operating the conditions).fuel does not Each pass sample through was a filter replicated in a required three times, time, and under the maximum standardized deviation instrument between and replications operating wasconditions). 1 ◦C for Each CFPP sample and 0.4 was◦C replicated for CP. The three average times, results and the are maximum presented deviat in Figureion between5. replications was 1 °C for CFPP and 0.4 °C for CP. The average results are presented in Figure 5.

20 20 Biodiesel HVO 10 BioButanol 10 o.bio 0 0 Biodiesel -10 -10 HVO BioButanol o.bio -20 -20 Cloud Cloud Point (ºC) -30 -30

Cold Filter Plugging Point (ºC) Point Plugging Filter Cold -40

-40 -50 0 102030405060708090100 0 102030405060708090100 Biofuel content (%v/v) Biofuel content (%v/v)

Figure 5. Cloud point ( leftleft) and Cold filter ﬁlter plugging point (right) of fuels and blends.

Both properties evolved quite similarly, andand thethe valuesvalues werewere veryvery close.close. Biobutanol was not measured as its its CP CP and and CFPP CFPP values, values, around around −9090 °C◦ (theC (the freezing freezing point point of n-butanol), of n-butanol), are areoutside outside the − ® theinstrument instrument range. range. The TheCP/CFPP CP/CFPP values values for foro.bio® o.bio werewere better better than than for for biodiesel, biodiesel, this this being being a ® aconsequence consequence ofof the the acetal acetal content content in in o.bio®, o.bio ,whic whichh acts acts as as a a cold cold flow flow improver. Moreover, neat biodiesel is out of the POFF specification in EN 14214 ( 10 C in winter and 0 C in summer, in Spain), biodiesel is out of the POFF specification in EN 14214 (−−10 °C◦ in winter and 0 °C◦ in summer, in Spain), which should be corrected byby increasingincreasing thethe flowflow improversimprovers dose.dose. Despite thethe low low freezing freezing point point of n-butanol,of n-butanol, blends blends up to up 20% to biobutanol 20% biobutanol content content did not decreasedid not thedecrease diesel the CP /dieselCFPP CP/CFPP values, which values, indicates which that,indicates for diesel that,/ biobutanolfor diesel/biobutanol blends, the blends, cold flow theproperties cold flow areproperties exclusively are exclusively determined bydetermined the diesel by fraction. the dies Dieselel fraction./HVO blends Diesel/HVO behaved blends linearly, behaved being thelinearly, HVO propertiesbeing the HVO better properties than those better of diesel than fuel. those In of the diesel case offuel. neat In HVO,the case the of di neatfference HVO, between the difference CP and CFPPbetween is larger CP and than CFPP for theis larger other than fuels. for Larger the other differences fuels. Larger between differences CP and CFPP between are typical CP and in CFPP fuels that are havetypical been in fuels largely that additivated have beenwith largely flow additivated improvers, with since flow these improvers, additives since are not these effective additives in depleting are not CPeffective as they in aredepleting in CFPP. CP as they are in CFPP. ® The coldcold flowflow propertiesproperties of of biodiesel biodiesel and and o.bio o.bio®blends blends in in diesel diesel did did not not change change linearly, linearly, and and the valuesthe values exhibited exhibited by theby blendsthe blends resulted resulted worse worse than th expectedan expected if the if tendencythe tendency had had been been linear. linear. In the In casethe case of biodiesel of biodiesel/diesel/diesel blends, blends, blends blends up to up 20% to biodiesel 20% biodiesel content content meet the meet specification the specification for winter, for winter, POFF lower than −10 °C (comparatively, if the CFPP of these blends had evolved linearly with the biodiesel content, up to 35% biodiesel would have been admissible).

4.6. Cetane Number Cetane number evaluates the autoignition quality of diesel fuel. The higher the cetane number, the shorter the ignition delay time of the fuel (defined as the elapsed time between the fuel injection and the start of the fuel combustion) when injected into the combustion chamber. Historically, high cetane numbers are preferred to improve cold startability and reduce combustion noise (also emissions have been reported to depend on cetane number [24]), but the use of high injection

Energies 2019, 12, 2034 9 of 13

POFF lower than 10 C (comparatively, if the CFPP of these blends had evolved linearly with the − ◦ biodiesel content, up to 35% biodiesel would have been admissible).

4.6. Cetane Number Cetane number evaluates the autoignition quality of diesel fuel. The higher the cetane number, the shorter the ignition delay time of the fuel (defined as the elapsed time between the fuel injection and theEnergies start of2019 the, 12, fuel x FOR combustion) PEER REVIEW when injected into the combustion chamber. Historically, high9 of cetane 13 numbers are preferred to improve cold startability and reduce combustion noise (also emissions have beenpressures, reported downsized to depend engines on cetane and numbermulti-injection [24]), butstrategies the use have of high made injection cetane number pressures, less downsized critical. enginesEven in and new multi-injection combustion modes strategies and havedual madefuel conc cetaneepts, number a lower less cetane critical. number Even could in new be beneficial combustion modes[33]. Nevertheless, and dual fuel fuel concepts, standards a lower in Europe cetane set number a minimum could value be beneficial of 51 (diesel, [33]. biodiesel) Nevertheless, and 70 fuel standards(paraffinic in fuels). Europe set a minimum value of 51 (diesel, biodiesel) and 70 (paraffinic fuels). Each sample was measured once, but the given value is the average of 15 fuel injection events in Each sample was measured once, but the given value is the average of 15 fuel injection events the measuring instrument. Diesel fuel was replicated twice, and the deviation was less than 0.5 units. in the measuring instrument. Diesel fuel was replicated twice, and the deviation was less than The results, presented in Figure 6, show that HVO fuel has a very high cetane number as usual in 0.5 units. The results, presented in Figure6, show that HVO fuel has a very high cetane number paraffinic fuels, while neat biobutanol has an extremely low value (pure alcohols are more as usual in paraffinic fuels, while neat biobutanol has an extremely low value (pure alcohols are appropriate for spark ignition than for compression ignition engines). For diesel automotive moreapplications, appropriate biobutanol/diesel for spark ignition blends than should for compression be limited at ignition 10% biobutanol engines). content For diesel to maintain automotive a applications,cetane number biobutanol higher than/diesel 51. blends Sometimes should the be addition limited of at biodiesel 10% biobutanol to alcohol- contentdiesel to blends maintain has abeen cetane numberexplored higher to compensate than 51. Sometimes for the low the cetane addition number of biodiesel of alcohols to alcohol-diesel[34]. blends has been explored to compensateThe cetane for number the low cetaneof the o.bio® number fuel of alcoholswas close [34 to]. that of diesel, therefore all blends tested ® displayedThe cetane similar number values ofas thewell. o.bio In the casefuel of was the closebiodiesel to that fuel, of the diesel, cetane therefore number was all higher blends than tested displayedthat of diesel similar fuel values on account as well. of its In high the casesaturate of thed ester biodiesel content. fuel, Cetane the cetane number number does not was impede higher the than thatuse of of diesel o.bio®/diesel fuel on account and biodiesel/diesel of its high saturated blends at ester any concentration, content. Cetane although number high does concentrations not impede the usemay of o.bio not ®fulfill/diesel the and cetane biodiesel number/diesel limit blends if other at any more concentration, unsaturated although sources high are concentrationsused for biofuel may notproduction. fulfill the cetane number limit if other more unsaturated sources are used for biofuel production. 90

40 Biodiesel HVO 30 BioButanol Derived Cetane Number 20 o.bio

10 0 102030405060708090100 Biofuel content (%v/v) Figure 6. Derived cetane number of fuels and blends. Figure 6. Derived cetane number of fuels and blends. 4.7. Water Content 4.7.The Water water Content content of a fuel is an important property to be controlled since a high presence of water couldThe water lead content to corrosion of a fuel issues, is an microbial important growth proper andty to decrease be controlled fuel lubricity.since a high To preventpresencethese, of Europeanwater could Standards lead to ENcorrosion 590 and issues, EN 15940microbial limit growth the water and contentdecrease under fuel lubricity. 200 mg/ kg.To prevent these, EuropeanFigure7 Standards shows the EN water 590 and content EN 15940 of the limit samples the water tested content in this under work. 200 Allmg/kg. the fuels and blends were measuredFigure 7 shows three timesthe water and content deviation of the never samples exceed tested 20 mg in/ kgthis between work. All replications. the fuels and Neat blends diesel andwere HVO measured showed three water times contents and deviation below 50 never mg/kg. exceed Both fuels20 mg/kg meet between their respective replications. quality Neat standards, diesel andand therefore HVO showed all HVO water/diesel contents blends. below Biodiesel 50 mg/kg. presentedBoth fuels meet a higher their waterrespective content quality than standards, HVO and diesel,and therefore but still belowall HVO/diesel the limit ofblends. the standard Biodiesel EN presented 14214 (500 a higher mg/kg). water O.Bio content® fuel than presented HVO similarand valuesdiesel, of but water still contentbelow the than limit biodiesel, of the standard which provesEN 14214 the (500 higher mg/kg). hygroscopicity O.Bio® fuel presented of esters compared similar tovalues hydrocarbons. of water content than biodiesel, which proves the higher hygroscopicity of esters compared to hydrocarbons.

Energies 2019, 12, 2034 10 of 13 Energies 2019, 12, x FOR PEER REVIEW 10 of 13

400

350 Biodiesel HVO 300 BioButanol o.bio 250

200

150

100 Water Water Content (mg/kg) 50

0 0 102030405060708090100 Biofuel Content (%v/v) FigureFigure 7. 7. WaterWater content content of fuels andand blends.blends. 5. Conclusions 5. Conclusions The work presented measured the main fuel properties of four selected advanced biofuels and The work presented measured the main fuel properties of four selected advanced biofuels and their blends with a fossil diesel fuel. Analyzing the properties and comparing the values with the theirlimits blends imposed with ina thefossil involved diesel fuel. fuel qualityAnalyzing standards, the properties the feasibility and comparing of some blends the values at low biofuelwith the limitscontent imposed has been in the proved. involved Biofuel fuel properties, quality standard along withs, the other feasibility features (sustainability,of some blends greenhouse at low biofuel gas contentbalance, has economic been proved. prospective), Biofuel properties, must be considered along with when other selecting features the (sustainability, most adequate greenhouse biofuels and gas balance,blending economic ratios to prospective), be accepted by must all stakeholders be considered involved. when selecting the most adequate biofuels and blendingIn ratios the case to ofbe HVO, accepted waste by acid-derived all stakeholders biodiesel involved. and o.bio ® (a blend of fatty acid methyl esters andInfatty the case acid of glycerol HVO, formal waste methylacid-derived esters), biodiesel blends up and to 20% o.bio® content (a blend in biofuel of fa havetty acid been methyl suggested esters andhere. fatty For acid HVO glycerol blends, formal higher methyl blending esters), ratios blends could up provoketo 20% content a lubricity in biofuel loss if have the HVObeen suggested was not here.additivated For HVO with blends, lubricity higher enhancers. blending For ratios the ester-based could provoke biofuels, a higherlubricity blending loss if ratios the HVO could derivewas not additivatedin poor cold with flow lubricity properties enhancers. and density For the and ester-based heating values biofuels, too di higherfferent blending from those ratios assumed could when derive in poorcalibrating cold flow the cartography properties ofand the density engine. and Biobutanol heating blends values must too different be further from restricted those to assumed 10% butanol when calibratingcontent to the avoid cartography excessive of water the engine. content Biobutanol and very low blends cetane must number be further and heating restricted value. to 10% butanol contentThough to avoid not excessive evaluated water here, content the results and found very anticipatelow cetane the number potential and of heating ternary blendsvalue. prepared withThough diesel not and evaluated two of the here, biofuels the hereresults explored. found antici The effpateect ofthe one potential biofuel inof oneternary particular blends property prepared withcan diesel be compensated and two of the with biofuels the reverse here eexplored.ffect of other The biofuels,effect of resultingone biofuel in in a neutral one particular blend with property the cansame be compensated property value with than the that reverse of the effect reference of other diesel biofuels, fuel. This resulting would in be a theneutral case blend of density with of the samediesel property/biodiesel value/HVO than blends, that which of the could reference be produced diesel in fuel. a single This plant would and whosebe the composition case of density could of be selected to have, in the final blend, the same density as the diesel fuel used for blending. diesel/biodiesel/HVO blends, which could be produced in a single plant and whose composition couldAuthor be selected Contributions: to have,Conceptualization, in the final blend, J.J.H. the and same J.R.-F.; density methodology, as the J.R.-F.; diesel validation, fuel used A.C.-A., for blending.Á.R. and J.B.; formal analysis, Á.R.; investigation, A.C.-A.; data curation, J.B.; writing—original draft preparation, A.C.-A., AuthorÁ.R. andContributions: J.B.; writing—review Conceptualization, and editing, J.J.H. J.R.-F.; and supervision, J.R.-F.; methodol J.J.H.; fundingogy, J.R.-F.; acquisition, validation, J.J.H. A.C.-A., and J.R.-F. Á.R. and J.B.; formal analysis, Á.R.; investigation, A.C.-A.; data curation, J.B.; writing—original draft preparation, A.C.- Funding: The Spanish Ministry of Economy, Industry and Competitiveness is also acknowledged for financing A.,the Á.R. research and J.B.; project writing—review ENE2016-79641-R and editing, and for J.R.-F.; and for supervision, funding A. J.J.H.; Calle funding through acquisition, the pre-doctoral J.J.H. grant and J.R.-F. with reference BES-2017-079668. Funding: The Spanish Ministry of Economy, Industry and Competitiveness is also acknowledged for financing theAcknowledgments: research project ENE2016-79641-RRepsol, NESTE, Masoland for Iberia and Biofuel,for fund Greening A. Biologics Calle through and Inkemia-IUCT the pre-doctoral aregratefully grant with acknowledged for supplying the fuels tested in this work. reference BES-2017-079668. Conflicts of Interest: The authors declare no conflict of interest. Acknowledgments: Repsol, NESTE, Masol Iberia Biofuel, Green Biologics and Inkemia-IUCT are gratefully acknowledgedAppendix A. for Values supplying of the the Properties fuels tested Measured in this work. in This Work and by the Suppliers ConflictsThe of valuesInterest: of The all authors properties declare here no analyzed conflict of are interest. collected in Table A1, together with some other properties of the diesel fuel that were not measured in this work (but the values were measured Appendixby the supplier). A. Values of the Properties Measured in This Work and by the Suppliers The values of all properties here analyzed are collected in Table A1, together with some other properties of the diesel fuel that were not measured in this work (but the values were measured by the supplier).

Energies 2019, 12, 2034 11 of 13

Table A1. Values of the properties measured in this work and by the suppliers.

Biodiesel HVO BioButanol o.bio Properties Diesel 5 10 15 20 30 50 100 5 10 15 20 30 50 100 5 10 15 20 100 5 10 15 20 100 3 Density at 15 ◦C (kg/m ) 829 831 833 837 840 845 853 876 828 825 823 821 815 805 780 829 827 826 826 813 833 836 839 843 907 Kinematic viscosity at 2.92 2.68 2.82 2.87 3.00 3.14 3.42 5.08 2.65 2.71 2.64 2.72 2.83 2.86 3.21 2.56 2.43 2.34 2.34 2.48 2.90 2.92 2.95 3.01 6.07 40 ◦C (cSt) Lower Heating Value 43.0 42.6 42.4 42.1 41.8 41.1 39.9 36.9 43.1 43.2 43.2 43.2 43.4 43.6 44.3 42.3 42.0 41.4 40.7 32.7 42.5 42.2 41.8 41.2 35.0 (MJ/kg) Lubricity (µm) 330 315 286 196 195 213 194 186 372 396 408 424 454 467 416 386 372 381 409 568 278 194 191 189 183 Cloud Point ( C) 22.1 16.6 12.4 9.7 6.8 1.9 4.6 13.1 23.0 23.3 24.2 25.4 26.1 26.7 32.5 22.4 22.8 22.8 22.5 128.6 19.4 17.0 14.4 12.9 3.5 ◦ − − − − − − − − − − − − − − − − − − − − − − Cold ﬁlter plugging point 24 22 17 13 9 5 2 12 24 26 27 28 31 32 44 24 24 24 25 - 20 19 17 16 2 (◦C) − − − − − − − − − − − − − − − − − − − − − Derived cetane number 58.29 60.47 61.75 62.56 62.47 63.77 64.81 66.94 62.53 63.36 64.33 63.95 68.27 71.60 80.06 54.81 51.36 49.62 47.14 15.92 58.27 58.50 57.33 56.98 54.83 Water content (mg/kg) 24 68 94 100 110 136 184 276 26 28 29 30 31 35 40 106 171 242 344 1582 37 53 71 93 307

T10 (◦C) 229.5 ------262.4 ------

T50 (◦C) 261.5 ------278.9 ------

T95 (◦C) 304.0 ------296.1 ------Sulfur (mg/kg) 7 ------<5 ------<1 ------Energies 2019, 12, 2034 12 of 13

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