Biobased Diesel Fuel Analysis and Formulation and Testing of

Article Cite This: Ind. Eng. Chem. Res. XXXX, XXX, XXX−XXX

pubs.acs.org/IECR

Biobased Diesel Fuel Analysis and Formulation and Testing of Surrogate Fuel Mixtures Dianne J. Luning Prak,*,† Sonya Ye,† Margaret McLaughlin,† Paul C. Trulove,† and Jim S. Cowart‡ †

Department of Chemistry, U.S. Naval Academy, 572 M Holloway Road, Annapolis, Maryland 21402, United States Department of Mechanical Engineering, U.S. Naval Academy, 590 Holloway Road, Annapolis, Maryland 21402, United States

‡

S Supporting Information *

ABSTRACT: The properties and chemical components of a bioderived alternative diesel fuel were used to formulate hydrocarbon mixtures for use as fuel surrogates. This alternative diesel fuel was found to contain mostly alkylcyclohexanes, linear alkanes, and alkylbenzenes, with small amounts of other compounds as determined by gas chromatography/mass spectrometry. Surrogate mixtures were prepared containing nhexadecane, n-hexylbenzene, and n-butylcyclohexane, and their derived cetane number (DCN), density, viscosity, speed of sound, surface tension, and flashpoint were measured to help formulate mixture compositions whose properties most closely matched those of the fuel. Engine tests of three 3-component surrogate mixtures using a Waukesha diesel Cooperative Fuels Research engine showed that the combustion behaviors (burn duration, ignition delay, thermal efficiency, and maximum rate of heat release) of the three surrogates were similar to those of the base bioderived fuel. Successful surrogates were designed using chemical composition, DCN, density, and speed of sound.

■

be used without blending (neat).22 A jet fuel produced by Applied Research Associates and Chevron Lummus Global, catalytic hydrothermal conversion-to-jet (CHCJ), was used neat in test flights by the military.23,24 This conversion process has also been used to produce diesel fuel for testing by the military. The goal of the current study was to characterize this diesel fuel, formulate surrogate mixtures as model chemical systems for the fuel, and test the fuel and its surrogates in a diesel engine. Surrogate mixtures are used in fuels research because the complex composition of conventional diesel and jet fuels poses difficulties for modeling their physical properties and combustion behavior. Modeling the complete combustion process requires knowledge of the thermochemical parameters (e.g., specific heats, bond strengths), reaction radicals and products formed, and the rate constants for each reaction, as well as the impact of the interactions of various components. Such knowledge is currently incomplete, and the simulations are beyond current computational capabilities.25 By using mixtures with a few components, researchers have been able to focus on quantifying the kinetic aspects of those components and use the resulting information in combustion simulations. For example, Westbrook et al.26 published the detailed kinetic

INTRODUCTION In recent years, a variety of alternative fuels and fuel-blending components derived from biomass have been produced that contain chemical components that differ from petroleum-based fuels and, therefore, may differ in their combustion behavior. Hydrotreated pyrolytic lignin and hydrodepolymerized cellulosic diesel fuel (HDCD) have been shown to contain predominantly alkylcyclohexanes, hydro-1-H indenes, and hydronapthalenes and other aromatic compounds, and the HDCD needed to be mixed with at least 60% petroleum-based diesel fuel to have the combustion behavior that fit within the metrics required for military engines.1−10 Jet fuel derived from isobutanol was found to contain mostly isododecane and isocetane.11 A 50/50 mixture of this fuel with petroleum-based jet fuel was used in a successful flight by a UH-60 Black Hawk helicopter.12 These fuel mixtures met the startup performance requirements of emergency diesel engines when the concentration of the isobutanol based fuel was less than 30%.11,13 Diesel fuel derived from farnesene contained mostly 2,6,10trimethyldodecane (∼92%), and its combustion in diesel engines fell just within the acceptance criteria for these engines.14,15 Synthetic isoparaffinic kerosene derived from various oil sources has been found to contain mostly linear and branched alkanes, and the Navy demonstrated that a 50/50 mixture of this kerosene with petroleum-based fuel could be used in its warships.16−21 More recent biobased fuels have differed in composition from petroleum-based fuels, but their combustion behavior has been good enough to enable them to This article not subject to U.S. Copyright. Published XXXX by the American Chemical Society

Received: Revised: Accepted: Published: A

October 25, 2017 December 12, 2017 December 18, 2017 December 18, 2017 DOI: 10.1021/acs.iecr.7b04419 Ind. Eng. Chem. Res. XXXX, XXX, XXX−XXX

Industrial & Engineering Chemistry Research

Article

chamber along with other factors, density and viscosity.49−51 Bulk modulus was selected, because studies have shown that it can impact injection timing (start of injection and injection delay) in diesel engines.17,52 All properties of this fuel could be matched by a mixture containing a large number of components, but the goal was to prepare simple mixtures; therefore, the mixture was limited to three compounds. During the formulation process, the chemical composition helped to narrow which components to select, while the physical properties and DCN were used to select the amounts of each component. This way both the physical and chemical aspects of the combustion process were part of surrogate formulation.

mechanism of linear alkanes including n-hexadecane that comprised of nine reactions classes in a high temperature regime (e.g., hydrogen atom abstraction) and 15 reaction classes in a low temperature regime (e.g., alkyperoxy radical isomerization). The fuel mechanism for n-hexadecane specifically included 940 species and 3878 reactions.26 Their mechanism successfully predicted the combustion behavior of n-alkanes in a variety of experimental systems whose results had been published by various researchers. The approach used to determine the composition of a fuel surrogate has varied depending on the fuel and the engine tested. Many approaches begin with chemical analysis to produce a list of potential compounds. The list is refined by selecting compounds that optimize the prediction of physical properties, combustion-related metrics, chemical properties, or chemical characteristics (thermal conductivity, density, distillation curve information, viscosity, speed of sound, lower heating value, research octane number, cetane number or derived cetane number, flash point, total sooting index).27−40 Fuel components have been grouped into categories from which are selected a representative compound or compounds to be used in the surrogate. In 2007, the Surrogate Diesel Fuel Working Group published a review of diesel fuel surrogates in response to a 2003 meeting of the National Institute of Standard and Technology workshop on Combustion Simulation Databases for Real Transportation Fuels. They subdivided the components of diesel into seven major classes: normal paraffins, isoparaffins, 1-ring and 2-ring naphthalenes, 1ring and 2-ring aromatic compounds, and naphtha-aromatic compounds.37 Different researchers have modified the classes of compounds to separate out cycloalkanes and to add methyl esters, which are found in biodiesel.32,33,36 The 2007 study recommended the following compounds be used in surrogate formulations: n-decane, n-dodecane, isooctane, heptamethylnonane, methylcyclohexane, n-decylbenzene, toluene, and 1methylnaphthalene.37 More recent studies have used a variety of compounds such as Mueller et al. work that formulated surrogate mixtures using various combinations of n-hexadecane, n-octadecane, n-eicosane, heptamethylnonane, 2-methylheptadecane, n-butylcyclohexane, 1,3,5-triisopropylcyclohexane, trans-decalin, perhydrophenanthrene, 1,2,4-trimethylbenzene, 1,3,5-triisopropylbezene, tetralin, and 1-methylnapthalene.33 They characterized the surrogates by measuring derived cetane number (DCN), various distillation curves, density, heat of combustion, lubricity, cloud point, melting point, fuel solidification at atmospheric and elevated pressure, elemental analysis, smoke point, sulfur content, flash point, corrosivity, kinematic viscosity, aromatic content, and surface tension. Modeling efforts have sought to predict combustion and physical property behaviors of diesel surrogates.38,41−47 The goals of the research presented herein were 1) to characterize a diesel fuel produced by the hydrothermal conversion process for testing in military engines, 2) formulate surrogate mixtures of this fuel based on its properties, and 3) test the fuel and the surrogates in a diesel engine. The components used in the surrogate were selected from the categories of compounds found in the fuel and optimized for physical properties and combustion metrics. The physical properties and combustion metrics used were from military specifications48 for diesel fuel [derived cetane number (DCN), viscosity, density, and flash point)], along with surface tension, and bulk modulus. Surface tension was chosen because it influences the formation of fuel droplets in a combustion

■

EXPERIMENTAL SECTION Materials. The petroleum-based diesel fuel (F-76, lot 8576) and the biobased fuel (lot 9261) used in this study were provided by Naval Air Systems Command. The biobased fuel was produced by a catalytic hydrothermolysis and hydrotreating process by Applied Research Associates and Chevron Lummus Global, so the fuel will be called catalytic hydrothermal conversion diesel (CHCD) fuel. Their process uses a supercritical water to convert oils from plants, algae, and animals into a biocrude product, which is then hydrotreated using a proprietary catalyst to saturate the olefins and remove the oxygens.24 Fractionation of the resulting mixture is used to produce diesel fuel. Linear alkanes from hexane to octadecane (all from Aldrich with ≥99% purity), n-alkylcyclohexanes from propyl- to decyclcyclohexane (TCI, ≥98% purity, and butylcyclohexane from Aldrich, ≥99% purity), n-alkylbenzenes from propyl- to heptylbenzene (TCI, ≥97% purity), octylbenzene (Aldrich, ≥98% purity), indan (Aldrich, >95%), cis- and trans-decalin (TCI, ≥98% purity), and 1,2,3,4tetrahydronaphthalene (TCI, >98%) were used for the chemical analysis. Physical and Chemical Analysis. The hydrocarbons present in the CHCD were determined using gas chromatography/mass spectrometry methods described previously.22 Briefly, a temperature ramping program was used to separate compounds on a 5% diphenyl-arylene-95% dimethylpolysiloxane column before electron impact ionization, quadrapole mass separation, and detection of mass to charge ratios (m/z) from 30 to 600. The mass spectra of compounds found in the CHCD were matched to patterns in the NIST/EPA/NIH Mass Spectral Library (Version 2.0 g) to determine which compounds had the closest spectral match. The presence of many of the compounds was verified by using pure compounds to confirm that the retention time and mass fragmentation pattern of a compound in the fuel matched that of the pure compound. The amount of each component was estimated in this study using the peak areas. The fuel properties quantified in this work are those that affect fuel delivery to an engine and the formation of the spray pattern within the engine: bulk modulus (calculated from speed of sound and density), surface tension, viscosity, and density. Combustion was examined using flash point and DCN, which is described in the combustion analysis below. The measurement procedures have been described in previous studies with instruments tested and calibrated with NIST-traceable and certified standards.9,53−56 Briefly, viscosity, speed of sound, density, flash point, and surface tension were measured using a Stabinger Viscometer (Anton Parr SVM 3000), a Density and Sound Analyzer (Anton Parr DSA 5000), a Setaflash Series 8 flash point tester (Stanhope-Seta Model 82000-0, closed-cup), B

DOI: 10.1021/acs.iecr.7b04419 Ind. Eng. Chem. Res. XXXX, XXX, XXX−XXX


Article

and an Axisymmetric drop shape analyzer (Kruss DS100), respectively. The flash point tester was operated using flash/no flash mode and temperature ramping conditions, in conformance with ASTM methods E502, D3278, and D7236. Replicate measurements (2 to 80) were used to determine precision. Isentropic bulk modulus, Ev, was calculated from the speed of sound (c) and density (ρ): Ev = c 2ρ

(1)

Ignition Quality Tester and Diesel Engine Combustion Analysis. While flashpoint is a metric for assessing combustibility with a spark, the Advanced Engine Technology Ltd.’s (AET) Ignition Quality Tester (IQT) unit is more similar to a diesel engine, because the measured process is autoignition even though the reaction is run in a constant volume chamber. The IQT determines the derived cetane number (DCN) according the ASTM D6890 Standard Test Method.57 The IQT chamber pressure was set to 21 bar, and the preinjection compressed air temperature was set to 760 K. Such high temperatures are produced by nine cartridge heaters that are arranged around the circumference of the outside of chamber. The air intake is computer controlled, and the mechanical injection event is pneumatically controlled. Each experiment involves determining the ignition delay (IGD) for 32 individual combustion events, and the DCN is determined from the average IGD. Further details on the IQT used in this study can be found in Luning Prak et al.58 The IQT was used to test the CHCD and potential surrogate mixtures. The results were used to help determine the mole fractions of components in the surrogates that would be tested in the engine. The CHCD fuel and three surrogate mixtures were evaluated in the Waukesha diesel Cooperative Fuels Research (CFR) engine (F-5 Cetane Rating Engine). The combustion experiments were run at 900 rpm, a fixed compression ratio of 16.5, and fuel injection timing set for the best torque at lighter engine loads. To simulate the variable load operations found for diesel engines in actual operation, the fuel amount was varied. This experimental approach has been shown to provide an effective way to compare different fuels.59 Additional modifications allowed for in-cylinder pressure sensing and the determination of air and fuel flow rates. In-cylinder combustion data were analyzed using a conventional MIT based first-law single zone analysis59−63 to determine start of combustion, ignition delay, maximum rate of heat release, and combustion burn duration. In-cylinder pressure based combustion metrics produce a more rigorous comparison of fuel differences that are not possible with brake-dynamometer measurements alone (e.g. torque, fuel flow).

■

Figure 1. Chromatograms from the GC/MS of petroleum F-76 and CHCD. Some of the data in this plot were shown in ref 22.

matched. The hydrocarbons that were confirmed (Table 1) were estimated to make up approximately 60% of the mixture with 44.8% paraffins, 17% cycloalkanes, 5% aromatic compounds, and a small amount of tetralin. The mass spectra of each compound and the peak found at the same retention time in the CHCD are given in the Supporting Information. Table 1. Compounds Found in CHCD Confirmed by Matching the Retention and Mass Spectral Pattern of Original Standards with Compounds Found in the Fuel compound

retention time (min) n-Paraffins

nonane decane undecane dodecane tridecane tetradecane pentadecane hexadecane heptadecane octadecane

3.927 5.528 7.141 8.678 10.128 11.476 12.749 13.972 15.093 16.177 Cycloalkanes

n-propylcyclohexane n-butylcyclohexane n-pentylcyclohexane n-hexylcyclohexane n-heptylcyclohexane n-octylcyclohexane n-nonylcyclohexane n-decylcyclohexane

RESULTS AND ANALYSIS

The composition of the CHCD fuel differs from petroleumderived fuel as described in a preliminary analysis where results suggested the presence of linear alkanes, alkylbenzenes, and alkylcyclohexanes.22 Figure 1 shows more peaks in the F-76 chromatogram at shorter and longer retention times, suggesting the presence of higher and lower boiling point components, respectively. The specific compounds in CHCD were determined by first determining the best match between the spectral pattern of compounds in the fuel and compounds in the NIST mass spectral database.22 Then, commercially available original standards of those compounds were analyzed to determine if both retention time and mass spectral pattern

4.456 6.095 7.733 9.308 10.70 12.144 13.442 14.665

Aromatic Compounds n-butylbenzene n-pentylbenzene n-hexylbenzene n-heptylbenzene n-octylbenzene trans-decahydronaphthalene Tetralin/Indans 1,2,3,4-tetrahydronaphthalene C

6.468 8.059 9.589 11.004 12.731 6.564 8.162



Article

Table 2. Comparison of Selected Propertiesa of CHCD and Petroleum F-76 Diesel with Military Specifications48 density at 288.15 Kb (g mL−1) 4.3 2.70

>60 63 ± 2

27.8 ± 0.2

1373.6

1590

1370.3

1532

2 −1

0.8194

93 ± 1

2.67 −3

2 −1

27.6 ± 0.3 −1

−1

The errors in the measurements are 0.02 kg·m , 0.06 mm ·s , 0.4 m·s , 0.5 MPa, 0.1 mN·m , and 1 K for density, viscosity, speed of sound, bulk modulus, surface tension, and flash point, respectively. bExtrapolated from data at 20 °C and higher. cReference 22.

a

Table 3. Comparison of Physical Property Information of CHCD, Pure Components, and the Surrogate Mixturesa substance or mixture

−3

density (kg·m )

2 −1

kinematic viscosity (mm ·s )

−1

speed of sound (m·s )

bulk modulus (MPa)

815.9 2.67 1370.3 1532 CHCDb n-hexylbenzene 857.68c 1.42c 1376.1c 1624c c c c n-hexadecane 773.41 2.91 1357.2 1425c n799.3d 1.22d 1328.4d 1411d butylcyclohexane Low aromatic surrogate: x = 0.224 hexylbenzene, x = 0.194 hexadecane, and x = 0.582 butylcyclohexane 803.5 1.54 1341.7 1446 Medium aromatic surrogate: x = 0.492 hexylbenzene, x = 0.254 hexadecane, and x = 0.254 butylcyclohexane 814.8 1.66 1352.8 1491 High aromatic surrogate: x = 0.620 hexylbenzene, x = 0.285 hexadecane, and x = 0.095 butylcyclohexane 819.9 1.74 1358.7 1513

surface tension (mN·m )

flash point (°C)

derived cetane number

27.6 29.5c 27.2c 26.7d

93.3 87c 134c 52d

60 33.3 100 48.8

27.2

63

59.1

27.8

84

59.5

28.2

87

60.6

−1

a

The measurements are reported at 293.15 K except for surface tension, which is reported at 294 K, and dynamic viscosity, which is reported at 313.15 K. The errors in the measurements are 0.1 kg·m−3, 0.06 mm2·s−1, 0.6 m·s−1, 0.8 MPa, 0.1 mN·m−1, and 1 K for density, viscosity, speed of sound, bulk modulus, surface tension, and flash point, respectively. DCN variability is ±1 based on the authors’ experience. bReference 22. c Reference 56. dReference 54.

peak and is generally used as a model compound for diesel fuel. n-Butylcyclohexane was chosen to represent the alkylcyclohexanes, because it was more reasonably priced than the longer alkylcylohexanes for preparing large samples for combustionbased operation in diesel engines. For the aromatic compounds, n-hexylbenzene was selected, because it also was more reasonably priced than the longer chain alkylaromatic compounds, but it was more viscous (1.19 mPa·s at 313.15 K) than n-butylbenzene (0.801 mPa·s at 313.15 K), which is commonly used in surrogate mixtures.53,56 A study65 of some of the properties of mixtures containing these components suggested that ternary mixtures could produce properties that matched many of those of the CHCD. The selection of the exact compositions for the surrogates involved using the speed of sound, density, and DCN of the CHCD as target values for the surrogate mixtures. The surface tension, viscosity, and flash point were also measured for comparison. Ternary mixtures containing a range of mole fractions of nhexadecane, n-hexylbenzene, and n-butylcyclohexane were evaluated in the IQT. A summary of the DCN results is shown in Figure 2, with the vertical color scale showing the resultant DCN. The aromatic n-hexylbenzene content increases from the top of the figure to the near center, thus the highest aromatic content is indicated by the indigo color. Increasing amounts of n-hexylbenzene decreases the DCN. Aromatic compounds are much less reactive than linear and cycloalkanes; therefore, lower values of DCN at higher concentrations are expected. Based on DCN of CHCD, the target surrogate value should be 60 ± 1, which is a light blue color DCN result. Three mixtures of differing concentrations of n-hexadecane, nhexylbenzene, and n-butylcyclohexane were prepared whose DCN, density, speed of sound, and surface tension were within

The viscosity, speed of sound, and surface tension of CHCD match those of F-76, but the density and bulk modulus are lower, while the flashpoint is higher (Table 2). Both fuels meet the diesel fuel military specifications.48 A recent report by the Coordinating Research Council examined the properties of diesel fuels and several alternative diesel fuels, one of which was produced by ARA and Chevron hydrothermolysis process called ReadiDiesel (designated RD3 in the report).64 The diesel fuel provided to the Navy for testing differed from the ReadiDiesel, which suggests that the process can be modified to produce diesel fuels with varying compositions. The report said that the ReadiDiesel had a high monoycloparaffin content especially at C17 (undecylcyclohexane), and its plots suggested that the n-alkane with the largest concentration was n-dodecane. While cyclohexanes are an important category of components in the CHCD, alkylcylohexanes larger than decylcyclohexane were not found. The n-alkane in the highest concentration in CHCD was n-hexadecane, which is the highest peak of all compounds in Figure 1. The properties of the CHCD also differed from those of the ReadiDiesel. The DCN of ReadiDiesel (52 ± 3), the viscosity at 40 °C (2.096 mm2·s−1), and flash point (72 °C) were lower, and the density at 15 °C (0.8305 specific gravity) was higher than the CHCD values given in Tables 2 and 3.64 Formulation of Surrogate Mixtures for CHCD. The surrogate was formulated using hydrocarbons from the major categories of compounds found in CHCD: paraffins, alkylcylohexanes (monocycloparaffins), and aromatic compounds. These are the same major categories of components found in petroleum-based fuels, and not all these categories of compounds have been found in other biobased fuels. For paraffins, n-hexadecane was selected since it was the largest D



Article

provides information on the location of the crank angle when various amounts of energy have been released. Thermal efficiency quantifies the conversion of heat energy into work in a diesel engine, and values of 30 to 40% are often found for military diesel fuel, F-76. The ultimate value is largely a function of engine size. In this work, thermal efficiencies were determined from in-cylinder combustion data that were analyzed using an engine-based energy-heat release first law of thermodynamics approach.49 For the CHCD and the surrogate mixtures, the thermal efficiency was lowest at the lowest engine loads (low gIMEP), increased to a maximum at midloads, and then decreased again at high loads (Figure 3). At Figure 2. IQT based DCN results for 3-component surrogates containing various mole fractions of n-hexadecane, n-butylcyclohexane, and n-hexylbenzene. The red arrow indicates the increase in nhexylbenzene concentration, which starts low on the top of the figure and is the highest at the bottom of the figure.

2% of those values for CHCD (Table 3). These mixtures were used in the combustion experiments: 1) xn‑hexylbenzene = 0.620, xn‑hexadecane = 0.285, and xn‑butylcyclohexane = 0.095 (high aromatic surrogate); 2) xn‑hexylbenzene = 0.492, xn‑hexadecane = 0.254, and xn‑butylcyclohexane = 0.254 (medium aromatic surrogate); and xn‑hexylbenzene = 0.224, xn‑hexadecane = 0.194, and xn‑butylcyclohexane = 0.582 (low aromatic surrogate). Some of the other properties of the surrogates did not match those of the CHCD as well as did the density, speed of sound, surface tension, and DCN. There were small differences in bulk modulus, with the greatest difference being 86 MPa found between the low aromatic surrogate and CHCD. This difference, however, is not likely to cause a significant change in diesel engine metrics. Tat and van Gerpen52 reported that 169 MPA, a much larger difference in bulk modulus, was needed to produce a 0.5° advancement in timing. In work in our laboratories, we found that a bulk modulus of greater than 200 MPa was needed to cause the start of injection to occur 1.5° earlier.17 Larger differences between the surrogates and CHCD properties were found for flash points (30 °C difference) and viscosities (∼40% smaller). While flashpoint is a specification for military diesel fuel, it is more of a metric for spark engines than for diesel engines, so the differences may have less of an impact on diesel metrics. In modeling the ignition delay (IGD) in an engine, the IGD has been broken into “physical delay”, which accounts for the pumping, injection, fuel spray pattern in the combustion chamber, and vaporization, and into “chemical delay”, which accounts for combustion.66,67 Viscosity, density, and surface tension are key properties used in modeling the spray pattern of fuel droplets in an engine. If “chemical delay” dominates “physical delay” in an engine, then the viscosity will have less of an impact on IGD. The results from IGD for the surrogates and CHCD will be discussed later in this context. Diesel Engine Results. Various engine metrics are discussed below for variable load conditions. Each load is designated by gross mean effective pressures (gIMEP), which is directly proportional to engine torque. The gIMEP is calculated by dividing the integrated in-cylinder pressure times cylinder volume change by the engine’s displaced volume. The quotient has units of pressure and is called an “effective pressure”. Several calculated values are reported in crank angle degrees, where top dead center is 0°, and deg ATC is the angle after top dead center. The energy analysis of the in-cylinder metrics

Figure 3. Indicated engine thermal efficiency for CHCD fuel and three 3-component surrogate mixtures at various engine loads. × (green) CHCD, ○ High (xn‑hexylbenzene = 0.620, xn‑hexadecane = 0.285, and xn‑butylcyclohexane = 0.095), ◇ (red) Medium (xn‑hexylbenzene = 0.492, xn‑hexadecane = 0.254, and xn‑butylcyclohexane = 0.254), and □ (blue) Low (xn‑hexylbenzene = 0.224, xn‑hexadecane = 0.194, and xn‑butylcyclohexane = 0.582) aromatic content.

low engine loads, friction reduces the efficiency, while at high engine loads, the combustion itself becomes less efficient. Middle loading has less relative friction and more complete combustion leading to the highest efficiency. A comparison of the surrogates with the CHCD shows that all three surrogate mixtures matched the thermal efficiency of the CHCD within the error of the measurements at all loads tested. Ignition delay quantifies the timing between the start of fuel injection into the combustion chamber (Start of Injection, SOI) and when it begins combusting (Start of Combustion, SOC). When the IGD is too long, the engine may stall, because there is little or no combustion occurring. Short IGD can lead to longer overall burn durations, with resulting lower thermal efficiencies. IGD also impacts the emissions of particulate matter and the nitrogen oxides (NOx). In the current study, an injector pintle inductive pickup motion sensor was used to measure the SOI. The time at which 10% of the fuel energy has been released was designated as the SOC. For F-76 under the similar engine conditions, the IGD was up to 10% higher than that of the CHCD.22 When more torque is needed (higher gIMEP), then more fuel must be injected into the cylinder, and the time until 10% of the energy is released is longer. This produces the longer IGDs shown in Figure 4. A comparison of the surrogates with the CHCD shows that all three surrogate mixtures had matched the IGD of the CHCD at all engine torques tested within the error of the measurements. The maximum rate of heat release (maxROHR) is an indicator of the speed of the bulk combustion process once it gets started. Very fast maxROHR can result in excessive engine noise and potentially engine damage. CHCD and the surrogate E



Article

Figure 6. Burn duration as a function of engine load (gIMEP) for CHCD and the three 3-component fuel surrogates. × (green) CHCD, ○ High (xn‑hexylbenzene = 0.620, xn‑hexadecane = 0.285, and xn‑butylcyclohexane = 0.095), ◇ (red) Medium (xn‑hexylbenzene = 0.492, xn‑hexadecane = 0.254, and xn‑butylcyclohexane = 0.254), and □ (blue) Low (xn‑hexylbenzene = 0.224, xn‑hexadecane = 0.194, and xn‑butylcyclohexane = 0.582) aromatic content.

Figure 4. Ignition delay (IGD) as a function of engine load (gIMEP) for CHCD and the three 3-component fuel surrogates. × (green) CHCD, ○ High (xn‑hexylbenzene = 0.620, xn‑hexadecane = 0.285, and xn‑butylcyclohexane = 0.095), ◇ (red) Medium (xn‑hexylbenzene = 0.492, xn‑hexadecane = 0.254, and xn‑butylcyclohexane = 0.254), and □ (blue) Low (xn‑hexylbenzene = 0.224, xn‑hexadecane = 0.194, and xn‑butylcyclohexane = 0.582) aromatic content.

mixtures tested herein have maxROHR values whose magnitude is similar to that of petroleum-based military F-76 diesel fuel22 and therefore safe for engine use. A comparison of the surrogates with the CHCD shows that all three surrogate mixtures match the maxROHR of the CHCD within the error of the measurements (Figure 5). The low and medium

Figure 7. CAD50 - crank angle degree location where 50% of the fuel has burned as a function of engine load (gIMEP) for CHCD and the three 3-component fuel surrogates. × (green) CHCD, ○ High (xn‑hexylbenzene = 0.620, xn‑hexadecane = 0.285, and xn‑butylcyclohexane = 0.095), ◇ (red) Medium (xn‑hexylbenzene = 0.492, xn‑hexadecane = 0.254, and xn‑butylcyclohexane = 0.254), and □ (blue) Low (xn‑hexylbenzene = 0.224, xn‑hexadecane = 0.194, and xn‑butylcyclohexane = 0.582) aromatic content.

■

DISCUSSION In this study, three surrogate mixtures containing n-hexadecane, n-butylcyclohexane, and n-hexylbenzene that were designed to match the density, speed of sound, and DCN of CHCD were shown to have combustion metrics that emulated those of CHCD. These result shows the success of this approach in surrogate development. These compounds were present in the CHCD and also represent that main classes of compounds found in CHCD. Their presence in the mixture helps the surrogate to mimic the potential pool of radicals formed during combustion and better emulate the overall combustion behavior of CHCD. In this study, the viscosity of the surrogates did not match that of the CHCD. Kim et al.50 used Computational Fluid Dynamics Simulations to predict the impact of varying density, viscosity, surface tension, vapor pressure, heat of vaporization, and heat capacity on the penetration depth of a liquid spray and on ignition delay. They found that reducing the kinematic viscosity by a multiplier of 0.4 at 750 K caused an approximate 6% reduction in liquid penetration depth, but it only marginally affected ignition delay (less than a 0.5% change at most). In the current study, the viscosity differences between the surrogate and the CHCD are smaller than those studied by Kim et al.,50 which suggests that an impact of the viscosity difference might

Figure 5. maxROHR (rate of heat release) as a function of engine load (gIMEP) for CHCD and the three 3-component fuel surrogates. × (green) CHCD, ○ High (xn‑hexylbenzene = 0.620, xn‑hexadecane = 0.285, and xn‑butylcyclohexane = 0.095), ◇ (red) Medium (xn‑hexylbenzene = 0.492, xn‑hexadecane = 0.254, and xn‑butylcyclohexane = 0.254), and □ (blue) Low (xn‑hexylbenzene = 0.224, xn‑hexadecane = 0.194, and xn‑butylcyclohexane = 0.582) aromatic content.

aromatic surrogate mixtures have values that are the closer to that of the CHCD than the highest aromatic mixture. This might be expected because the compositional analysis suggests that the CHCD does not have a high level of aromatic compounds. Burn duration quantifies the “time” in crank angle degrees between when 10% and 90% of the fuel is burned. Higher engine loads require more fuel, so the burn duration is longer, as shown in Figure 6. As the burn duration increases, the crank angle position at which 50% of the fuel has burned (CAD50) also increases (is later in the engine cycle), as shown in Figure 7. A comparison of the surrogates with the CHCD shows that the three surrogates show statistically similar behavior in burn duration and CAD50 over the complete range of engine loads. F



Article

The prediction of DCN values is useful in surrogate development, but the DCN numbers for mixtures have only been found to be a linearly combination of DCNs of the components in some systems, and actual measurements help to ensure a match between the fuel and the surrogate mixture. Using an IQT, Haas et al.75 reported that DCNs of n-heptane mixtures with 1-butanol, 2-butanol, isobutanol, and ethanol decreased linearly as the mole fraction of alcohol in heptane increased from 0 to 80%. Blends of heptane with t-butanol did not exhibit linear behavior. Baumgardner et al.76 found that DCN of n-butanol/n-heptane mixtures and n-heptane/ isooctane mixtures determined by a Waukesha Fuel Ignition Tester decreased linearly with an increase in the mole fraction of the lower reactivity component over the mole fraction range of 0 to 80%. Both studies showed nonlinear declines of DCN when plotted as a function of volume fraction.75,76 Kuszewski et al.77 did show a linear decrease in DCN as a function of volume fraction for ethanol/diesel mixtures for the addition of up to 14% ethanol. Naser et al.78 reported DCNs and composition information on a volume basis for 27 Petroleum Reference Fuels. The use of their DCNs of n-heptane and isooctane78 and a DCN of 6 for toluene74 to predict the DCN number of mixtures using volume percent weighting results in a general underprediction of mixture DCNs with an average percent deviation of 6.4%. Accurate prediction of the DCN of a mixture from individual components can also be hindered by the presence of compounds that do not give reliable DCN numbers, because they do not combust very well. In the current study, the DCNs would have been predicted to be 55, 54, and 54 for the low, medium, and high aromatic blends, respectively, if a blending rule based on mole fraction was used. These values are 6 to 11% lower than the actual values of 59.1, 59.5, and 60.6 for the low, medium, and high aromatic blends, respectively. This shows the importance of measuring DCN when formulating surrogate mixtures due to the complexity of the combustion process. This study showed that a 3-component surrogate was successful in emulating the diesel combustion behavior of the CHCD fuel. The particular set of components investigated herein has not been examined previously for other diesel fuels, with the hexylbenzene being the newer component. It is important to expand the palette of compounds considered for use in surrogate mixtures. Recent modeling and laboratory studies have been examining the combustion of longer chain alkylbenzenes.79−85 The autoignition behavior has been measured for droplets of 2-component mixtures of n-alkanes (n-heptane through n-eicosane) and alkylbenzenes (toluene through n-octylbenzene).80 Surrogate mixtures of n-propylbenzene, n-butylbenzene, and n-heptane were used in shock tubes and rapid compression machines to simulate the ignition of ndecylbenzene.81 In a single cylinder compression ignition research engine, ignition delay was found to decrease as alkyl chain length on the alkylbenzene (heptyl-, octyl-, and dodecylbenzene) increased.82 The combustion kinetic behavior of newer studies involving hexylbenzene can be combined with other studies that have provided information on the kinetic behavior of n-hexadecane26 and butylcyclohexane.86−88 The high temperature reaction behavior of some jet fuel surrogates was modeled using an n-butylcyclohexane kinetics scheme that consisted of 80 reactions and 42 species.86 Various physical property and engine tests have been conducted on surrogates for petroleum-based diesel that have two components (n-decane and α-methylnaphthalene)89 and

not be found for ignition delay. In some cases, viscosity is an important but not the dominant parameter in spray patterns. Payri et al.72 found that the lengths of liquid penetration of nheptane and n-dodecane into a constant-pressure flow chamber depended most on their volatility and density. Chemical and physical factors impact ignition delay, and the DCN takes into account the physical aspects of the injected fuel (spray pattern and volatilization) as well the chemical reaction factors. On the other hand, viscosity impacts only the physical factors (spray pattern).66−68 Viscosity may become or appear to be less important when 1) chemical factors dominate physical factors or 2) other physical factors (such as volatilization or density), reduce the apparent impact on viscosity. The contributions of chemical and physical factors to ignition delay have been found to depend on the chemical compound studied, engine type used, and engine load.63,66−71 In a singlecylinder diesel engine, the physical factors were shown to contribute only a small amount to the IGD for cyclohexane, while they contributed the same amount as the chemical factors to the IGD for n-hexane and 1-hexene.63 Combustion experiments with n-hexadecane in a Humvee engine indicated that chemical delay contributed more than physical delay to overall ignition delay,69 while in a Yanmar L48 V diesel engine with a common rail injection system, the ratio of chemical ignition delay period to physical ignition delay period ranged from 0.2 to 4 depending on the model conditions, the injection pressure, and the engine speed.71 Either the engine conditions or the components themselves may have resulted in the dominance of chemical factors over physical factors in the combustion process in the current study. The larger viscosity for the CHCD should produce larger fuel droplets than for the lower viscosity surrogates. If the heat of vaporization of CHCD was smaller than the surrogates, however, it could counteract the impact of the droplet size. It is possible that other factors not measured in the current are counteracting the differences in the viscosity. It is important to note that many surrogates containing a few components do not match all the physical properties of the fuel for which they are designed, and they are still successful in matching engine metrics of the fuel. In this study, the DCN was one of the key metrics in the determining the composition of the surrogate components selected. Some researchers have used DCN in their formulation of surrogates for diesel fuel,32,33 but other researchers have not.28,38,73 Mueller et al.32,33 only used DCN, density, composition information, and advanced distillation curve for petroleum-diesel surrogates. Liang et al.44 used cetane number, lower heating value, C/H ratio by weight, and T50 from distillation curve, resulting in a surrogate containing tetradecane, decane, heptamethylnonane, and 1-methylnaphthalene. Yu et al.73 developed surrogate mixtures for biodiesel by using the structure of the molecules. Surrogate formulation using DCN requires experimentally determined values, which have been reported in recent publications.58,74 DCN values reported herein of 100 and 48.8 agree with the values summarized by Yanowitz et al.74 of 100.5 and 48 (47.6, 48.0) for n-hexadecane and n-butylcyclohexane, respectively, both using the same measurement method. Yanowitz et al.74 Compendium of Experimental Cetane Numbers provides a value for the cetane number of hexylbenzene of 26, but they indicate that the reference from which they obtained that value did not report its method. It is difficult to determine if this cetane number is comparable to the DCN reported herein of 33. G



Article

three components (n-propylcyclohexane, n-butylbenzene, 2,2,4,4,6,8,8-heptamethylnonane90 or n-heptane, toluene, 1hexene45). Mueller et al.33 reported diesel surrogate mixtures that contained from four to nine components. While all the surrogates contained n-alkanes (n-hexadecane and/or noctadecane, n-eicosane), the other components differed and included branched alkanes (isocetane, 2-methylheptadecane), polyaromatic compounds (1-methylnaphthalene), polycyclics (decalin, perhydrophenanthrene), partially hydrogentated aromatic compounds (tetralin), aromatic compounds (1,2,4trimethylbenzene, isopropylbenzene), and cycloalkanes (butylcyclohexane, 1,3,5-triisopropyl cyclohexane). A greater number of components in a surrogate not only enables more properties to be matched but also requires more information because each component in a surrogate must be further studied to gather kinetic data needed for simulations, such has been done in past modeling studies and are continually being updated.36,38,42,91−93

■

AUTHOR INFORMATION

Corresponding Author

*Phone: 410-293-6349. Fax: 410-293-2218. E-mail: prak@usna. edu. ORCID

Dianne J. Luning Prak: 0000-0002-5589-7287 Notes

The authors declare no competing financial interest.

■

■

ACKNOWLEDGMENTS This contribution was identified by Dr. Mariefel Olarte (Pacific Northwest National Laboratory) as the Best Presentation in the “ENFL: Advances in Chemistry of Energy & Fuels” session of the 2017 ACS Fall National Meeting in Washington, D.C. The authors wish to thank ONR’s (Office of Naval Research) NEPTUNE Project under the direction of Maria Medeiros (grant no. N0001417WX00892 and N0001418WX00142).

CONCLUSION This study sought to determine the chemical composition of a new generation of biofuel catalytic hydrothermal conversion diesel fuel (CHCD), to develop surrogate mixtures for the fuel based on physical and chemical properties, and to test those surrogates in a diesel engine. While the composition of this new biobased fuel differed from petroleum-based fuel, it did contain components from all the categories of compounds commonly used for petroleum-based fuels. Other alternative fuels only contain a subset of categories, such as isobutanol-based fuels which contain only isoalkanes. This fuel was designed for testing by the Navy, and its properties and composition differed from ReadiDiesel, which was produced in a similar process to the CHCD, and illustrates the fact that the process can be modified to produce designer diesel fuels. Using three components (n-hexylbenzene, n-butylcyclohexane, and nhexadecane) found in the fuel, three surrogate mixtures were formulated based on density, DCN, and speed of sound. Testing of these surrogates in a Waukesha diesel Cooperative Fuels Research engine showed that the combustion behaviors (burn duration, ignition delay, thermal efficiency, and maximum rate of heat release) of the three surrogates were similar to those of the CHCD. Such results show the success of using this approach to surrogate formulation. The DCNs of the mixtures were not linear combinations of the pure value DCNs on a mole fraction basis, which emphasizes the importance of actual DCN measurements for mixtures systems. For these surrogates, viscosity and flash point were not well matched, which suggests that the other properties were able to capture the physical and chemical behavior of the fuels in a diesel engine. The surrogate mixtures formulated in this study contained hexylbenzene, which is not commonly used in surrogate mixtures for diesel fuel. It is important to expand the palette of components used in surrogate mixtures to allow greater flexibility in developing surrogates for new fuels.

■

clohexane, trans-decahydronaphthelene, butylbenzene, pentylcyclohexane, undecane, 1,2,3,4-tetrahydronaphthalene, pentylbenzene, hexylcyclohexane, dodecane, hexylbenzene, tridecane, heptylcyclohexane, heptylbenzene, octylcyclohexane, tetradecane, phenyloctane, pentadecane, nonylcyclohexane, hexadecane, decylcyclohexane, heptadecane, octadecane) (PDF)

■

REFERENCES

(1) French, R. J.; Black, S. K.; Myers, M.; Stunkel, J.; Gjersing, E.; Iisa, K. Hydrotreating the organic fraction of biomass pyrolysis oil to a refinery intermediate. Energy Fuels 2015, 29, 7985−7992. (2) Kloekhorst, A.; Wildschut, J.; Heeres, H. J. Catalytic hydrotreatment of pyrolytic lignins to give alkylphenolics and aromatics using a supported Ru Catalyst. Catal. Sci. Technol. 2014, 4, 2367−2377. (3) Tsodikov, M. V.; Chudakova, M. V.; Chistyakov, A. V.; Maksimov, Y. V. Catalytic conversion of cellulose into hydrocarbon fuel components. Pet. Chem. 2013, 53, 367−373. (4) Piskorz, J.; Majerski, P.; Radlein, D.; Scott, D. S. Conversion of lignins to hydrocarbon fuel. Energy Fuels 1989, 3, 723−726. (5) Eide, I.; Neverdal, G. Fingerprinting bio-oils from lignocellulose and comparison with fossil fuels. Energy Fuels 2014, 28, 2617−2623. (6) Olcese, R.; Carre, V.; Aubriet, F.; Dufour, A. Selectivity of bio-oils hydrotreatment assessed by petroleomic and GC*GC/MS-FID analysis. Energy Fuels 2013, 27, 2135−2145. (7) Bond, J. Q.; Upadhye, A. A.; Olcay, H.; Tompsett, G. A.; Jae, J.; Xing, R.; Alonso, D. M.; Wang, D.; Zhang, T.; Kumar, R.; Foster, A.; Murat Sen, S.; Maravelias, C. T.; Malina, R.; Barrett, S. R. H.; Lobo, R.; Wyman, C. E.; Bumesic, J. A.; Huber, G. W. Production of renewable jet fuel range alkanes and commodity chemicals from integrated catalytic processing of biomass. Energy Environ. Sci. 2014, 7, 1500− 1523. (8) Carlson, T. R.; Cheng, Y.-T.; Jae, J.; Huber, G. W. Production of green aromatics and olefins by catalytic fast pyrolysis of wood sawdust. Energy Environ. Sci. 2011, 4, 145−161. (9) Luning Prak, D. J.; Luning Prak, P. J.; Trulove, P. C.; Cowart, J. S. Formulation of Surrogate Fuel Mixtures based on Physical and Chemical Analysis of Hydrodepolymerized Cellulosic Diesel Fuel. Energy Fuels 2016, 30, 7331−7341. (10) Bermudez, E.; Luning Prak, D.; Hamilton, L.; Cowart, J.; McDaniel, A.; Dickerson, T. S. Start-up and Steady-State Performance of a New Renewable Hydro-processed Depolymerized Cellulosic Diesel (HDCD) in Multiple Diesel Engines. J. Eng. Gas Turbines Power 2016, 138, 102807-1−101501-10. (11) Luning Prak, D. J.; Jones, M. H.; Trulove, P. C.; McDaniel, A. M.; Dickerson, T.; Cowart, J. Physical and Chemical Analysis of

ASSOCIATED CONTENT

* Supporting Information S

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.iecr.7b04419. Comparison of mass spectral peaks of the components found in CHCD with those commercially available standards (nonane, propylcyclohexane, decane, butylcyH



Article

jetstirred reactor: Experimental and modeling studies. Energy Fuels 2010, 24, 1668−1676. (31) Ramirez, H. P.; Hadj-Ali, K.; Dievart, P.; Dayma, G.; Togbe, C.; Moreac, G.; Dagaut, P. Oxidation of commercial and surrogate biodiesel fuels (B30) in a jet-stirred reactor at elevated pressure: Experimental and modeling kinetic study. Proc. Combust. Inst. 2011, 33, 375−382. (32) Mueller, C. J.; Cannella, W. J.; Bruno, T. J.; Bunting, B.; Dettman, H. D.; Franz, J. A.; Huber, M. L.; Natarajan, M.; Pitz, W. J.; Ratcliff, M. A.; Wright, K. Methodology for formulating diesel surrogate fuels with accurate compositional, ignition-quality, and volatility characteristics. Energy Fuels 2012, 26, 3284−3303. (33) Mueller, C. J.; Cannella, W. J.; Bays, T.; Bruno, T. J.; Defabio, K.; Dettman, H. D.; Gieleciak, R. M.; Huber, M. L.; Kweon, C.-B.; McConnell, S. S.; Pitz, W. J.; Ratcliff, M. A. Diesel surrogate fuels for engine testing and chemical-kinetic modeling: composition and properties. Energy Fuels 2016, 30, 1445−1461. (34) Lemaire, R.; Faccineeto, A.; Therssen, E.; Ziskind, M.; Fosca, C.; Desgroux, P. Experimental comparison of soot formation in turbulent flashes of Diesel and surrogate Diesel fuels. Proc. Combust. Inst. 2009, 32, 737−744. (35) Mathieu, O.; Djebaili-Chaumeix, N.; Paillard, C. E.; Douce, F. Experimental study of soot formation from a diesel fuel surrogate in a shock tube. Combust. Flame 2009, 156, 1576−1586. (36) Pitz, W. J.; Mueller, C. J. Recent Progress in the development of diesel surrogate fuels. Prog. Energy Combust. Sci. 2011, 37, 330−350. (37) Farrell, J. T.; Cernansky, N. P.; Dryer, F. L.; Friend, D. G.; Hergart, C. A.; Law, C. K., McDavid, R. M.; Mueller, C. J.; Patel, A. K.; Pitsch, H. Development of an experimental database and kinetic models for surrogate diesel fuels. 2007 SAE World Congress, 16−19 April 2017; SAE Paper 2007-01-0201. (38) Chang, Y.; Jia, M.; Li, Y.; Liu, Y.; Xie, M.; Wang, H.; Reitz, R. D. Development of a skeletal mechanism for diesel surrogate fuel by using a decoupling methodology. Combust. Flame 2015, 162, 3785−3802. (39) Huber, M. L.; Lemmon; Diky, V.; Smith, B. L.; Bruno, T. J. Chemical authentic surrogate mixture model for the thermophysical properties of a coal-derived fuel. Energy Fuels 2008, 22, 3249−3257. (40) Pei, Y.; Mehl, M.; Liu, W.; Lu, T.; Pitz, W. J.; Som, S. A. Multicomponent Blend of a Diesel Fuel Surrogate for Compression Ignition Engine Applications. J. Eng. Gas Turbines Power 2015, 137, 111502-1−111502-9. (41) Xiao, G.; Zhang, Y.; Lang, J. Kinetic modeling study of the ignition process of homogeneous charge compression ignition engine fueled with three-component diesel surrogate. Ind. Eng. Chem. Res. 2013, 52, 3732−3741. (42) Wang, F.; Zheng, Z.; He, Z. Reduced polycyclic aromatic hydrocarbon formation chemical kinetic model of diesel surrogate fuel for homogeneous charge compression ignition combustion. Energy Fuels 2012, 26, 1612−1620. (43) Ahmedi, A.; Ahmed, S. S.; Kalghatgi, G. T. Simulating combustion in a PCI (premixed combustion ignition) engine using DI-SRM and 3 components surrogate model. Combust. Flame 2015, 162, 3728−3739. (44) Liang, L.; Naik, C. V.; Puduppakkam, K.; Wang, C.; Modak, A.; Meeks, E.; Ge, H.-W.; Reitz, R.; Rutland, C. Efficient simulation of diesel engine combustion using realistic chemical kinetics in CFD. SAE Tech. Pap. Ser. 2010, Paper No. 2010-01-0178, DOI: 10.4271/201001-0178. (45) Luo, J.; Yao, M.; Liu, H. A reduced chemical kinetic mechanism for low temperature diesel combustion and soot emissions. Combust. Sci. Technol. 2014, 186, 1975−1990. (46) Wang, X.; Liu, H.; Zheng, Z.; Yao, M. A skeletal mechanism of a biodiesel surrogate fuel for compression ignition engines. Energy Fuels 2015, 29, 1160−1171. (47) Luo, Z.; Plomer, M.; Lu, T.; Som, S.; Longman, D. E.; Mani Sarathy, S.; Pitz, W. J. A reduced mechanism for biodiesel surrogates for compression ignition engine applications. Fuel 2012, 99, 143−153.

Alcohol-to-Jet (ATJ) Fuel and Development of Surrogate Fuel Mixtures. Energy Fuels 2015, 29, 3760−3769. (12) Bomgardner, M. M. Gevo isobutyl alcohol power Army Copter. Chem. Eng. News 2014, 92, 11. (13) Dickerson, T.; McDaniel, A.; Williams, S.; Luning-Prak, D.; Hamilton, L.; Bermudez, E.; Cowart, J. Start-up and steady-state performance of a new renewable alcohol-to-jet (ATJ) fuel in multiple diesel engines. SAE Tech. Pap. Ser. 2015, Paper No. 2015-01-0901, DOI: 10.4271/2015-01-0901. (14) Hamilton, L.; Luning Prak, D. J.; Cowart, J.; McDaniel, A.; Williams, S.; Leung, R. Direct Sugar to Hydrocarbon (DSH) Fuel Performance Evaluation in Multiple Diesel Engines. SAE Inter. J. Fuels Lubr. 2014, 7, 270−282. (15) Luning Prak, D. J.; Morris, R. W.; Cowart, J. S.; Hamilton, L. J.; Trulove, P. C. Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Direct Sugar to Hydrocarbon Diesel (DSH-76) and Binary Mixtures of N-Hexadecane and 2,2,4,6,6Pentamethylheptane. J. Chem. Eng. Data 2013, 58, 3536−3554. (16) Bruno, T. J.; Baibourine, E. Comparison of biomass-derived turbine fuels with Composition-Explicit Distillation Curve Method. Energy Fuels 2011, 25, 1847−1858. (17) Luning Prak, D. J.; Cowart, J. S.; Hamilton, L. J.; Hoang, D. T.; Brown, E. K.; Trulove, P. C. Development of a surrogate mixture for Algal-based hydrotreated renewable diesel. Energy Fuels 2013, 27, 954−961. (18) Steele, J. Navy tests algae fuel in former warship. The San Diego Union-Tribune LLC; Nov. 16, 2011. (19) Goldenberg, S. US navy completes successful test on boat powered by algae. The Guardian; Guardian News and Median Limited: October 27, 2010. (20) Fletcher, K. U.S. Navy launches Great Green Fleet with 2016 kickoff event. Biomass Magazine, Jan. 21, 2016. http:// biomassmagazine.com/articles/12820/us-navy-launches-great-greenfleet-with-2016-kickoff-event (accessed September 30, 2017). (21) Caton, P. A.; Williams, S. A.; Kamin, R. A.; Luning Prak, D.; Hamilton, L. J.; Cowart, J. S. Hydrotreated algae renewable fuel performance in a military diesel engine. In Proceedings of the 2012 Spring Technical Conference; May 6−9, 2012; American Society of Mechanical Engineers (ASME): Paper ICES2012-81048. (22) McDaniel, A.; Dickerson, T. S.; Luning Prak, D.; Hamilton, L.; Cowart, J. S. Technical Evaluation of New Renewable Jet and Diesel Fuels Operated in Neat Form in Multiple Diesel Engines. SAE Tech. Pap. Ser. 2016, Paper No. 2016-01-0829, DOI: 10.4271/2016-01-0829 (23) Watters, A. Navy tests 100-percent advanced biofuel. Naval Aviation News Story Number: NNS160916-03, Release Date: 9/16/ 2016. http://www.navy.mil/submit/display.asp?story_id=96702 (accessed 7/19/17). (24) ARA. https://www.ara.com/capabilities/advanced-biofuels-andrenewable-chemicals (accessed September 30, 2017). (25) Lu, T.; Law, C. K. Toward accommodating realistic fuel chemistry in large-scale computations. Prog. Energy Combust. Sci. 2009, 35, 192−215. (26) Westbrook, C. K.; Pitz, W. J.; Herbinet, O.; Curran, H. J.; Silke, E. J. A comprehensive detailed chemical kinetic reaction mechanism for combustion of n-alkane hydrocarbons from n-octane to nhexadecane. Combust. Flame 2009, 156, 181−199. (27) Das, D. D.; McEnally, C. S.; Kwan, T. A.; Zimmerman, J. B.; Cannella, W. J.; Mueller, C. J.; Pfefferle, L. D. Sooting tendencies of diesel fuels, jet fuels and their surrogates in diffusion flames. Fuel 2017, 197, 445−458. (28) Wood, C. P.; McDonell, V. G.; Smith, R. A.; Samuelsen, G. S. Development and application of a surrogate distillate fuel. J. Propul. Power 1989, 5, 399−405. (29) Ramirez Lancheros, H. P.; Fikri, M.; Rincon Cancino, L.; Moreac, G.; Shulz, C.; Dagaut, P. Autoignition of surrogate biodiesel fuel (B30) at high pressure: Experimental and modeling kinetic study. Combust. Flame 2012, 159, 996−1008. (30) Ramirez, H. P.; Hadj-Ali, K.; Dievart, P.; Moreac, G.; Dagaut, P. Kinetics of oxidation of commercial and surrogate diesel fuels in a I



Article

(48) Department of Defense, August 14, 2012, “Performance Specification Fuel, Naval Distillate,” Military Specification MIL-PRF16884M. (49) Heywood, J. Internal Combustion Fundamentals, 1st ed.; McGraw-Hill, Inc.: New York, 1988. (50) Kim, M.; Martz, J.; Violi, A. Effects of fuel physical properties on direct injection spray and ignition behavior. Fuel 2016, 180, 481−496. (51) Naber, J. D.; Siebers, D. L. Effects of gas density and vaporization on penetration and dispersion of diesel sprays. 1996, SAE Technical Paper 960034, 82-111, DOI: 10.4271/960034. (52) Tat, M. E.; van Gerpen, J. H. Measurement of Biodiesel Speed of Sound and Its Impact on Injection Timing: Final Report, Report 4 in a series of 6; for National Renewable Energy Laboratory, Golden, CO, February 2003; DOI: 10.2172/15003584. (53) Luning Prak, D. J.; Lee, B. G.; Trulove, P. C.; Cowart, J. S. Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Binary Mixtures of Butylbenzene + Linear Alkanes (n-Decane, n-Dodecane, n-Tetradecane, n-Hexadecane, or n-Heptadecane) at 0.1 MPa. J. Chem. Eng. Data 2017, 62, 169−187. (54) Luning Prak, D. J. Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Binary Mixtures of Butylcyclohexane + Toluene or + n-Hexadecane. J. Chem. Eng. Data 2016, 61, 3595−3606. (55) Luning Prak, D. J.; McDaniel, A. M.; Cowart, J. S.; Trulove, P. C. Density, viscosity, speed of sound, bulk modulus, surface tension, and flash point of binary mixtures of n-hexadecane + ethylbenzene or + toluene at (293.15 to 373.15) K and 0.1 MPa. J. Chem. Eng. Data 2014, 59, 3571−3585. (56) Luning Prak, D. J.; Luning Prak, P. J.; Trulove, P. C.; Cowart, J. S. Density, Densities and Viscosities at (293.15 to 373.15) K, Speeds of Sound and Bulk Moduli at (293.15 to 343.15) K, Surface Tensions, and Flash Points of Binary Mixtures of n-Hexadecane and Alkylbenzenes at 0.1 MPa. J. Chem. Eng. Data 2017, 62, 1673−1688. (57) ASTM Standard D6890-13be1, Standard Test Method for Determination of Ignition Delay and Derived Cetane Number (DCN) of Diesel Fuel Oils by Combustion in a Constant Vol. Chamber. In 2013 ASTM Annual Book of Standards: American Society for Testing and Materials (ASTM): West Conshohocken, PA, 2013; DOI: 10.1520/D6890. (58) Luning Prak, P.; Hamilton, L.; Luning Prak, D.; Cowart, J. Reference and Pure Component Fuel Performance in an Ignition Quality Tester Derived Cetane Rating Unit. SAE Int. J. Eng. 2017, 10, 1163−1173. (59) Cowart, J. S.; Hamilton, L. J.; Williams, S. A.; McDaniel, A. Alternative Diesel Fuel Combustion Acceptance Criteria for New Fuels in Legacy Diesel Engines. SAE Tech. Pap. Ser. 2013, Paper No. 2013-01-1135, DOI: 10.4271/2013-01-1135. (60) Gatowski, J. A.; Balles, E. N.; Chun, K. M.; Nelson, F. E.; Ekchian, J. A.; Heywood, J. B. Heat Release Analysis of Engine Pressure Data. SAE Tech. Pap. Ser. 1984, Paper No. 841359, DOI: 10.4271/841359. (61) Chun, K. M.; Heywood, J. B. Estimating Heat Release and Mass of Mixture Burned from SI Engine Pressure Data. Combust. Sci. Technol. 1987, 54, 133−143. (62) Carr, M. A.; Caton, P. A.; Hamilton, L. J.; Cowart, J. S.; Mehl, M.; Pitz, W. J. An Experimental and Modeling Based Study into the Ignition Delay Characteristics of Diesel Surrogate Binary Blend Fuels. J. Eng. Gas Turbines Power 2012, 134, 072803-1−072803-10. (63) Caton, P. A.; Hamilton, L. J.; Cowart, J. S. Understanding Ignition Delay Effects with Pure Component Fuels in a Single Cylinder Diesel Engine. J. Eng. Gas Turbines Power 2011, 133, 0328031−072803-11. (64) Cannella, W.; Fairbridge, C.; Gieleciak, R.; Arboleda, P.; Bays, T.; Dettman, H.; Foster, M.; Gunter, G.; Hager, D.; King, D.; Lay, C.; Lewis, S.; Luecke, J.; Sluder, S.; Zigler, B.; Natarajan, M. CRC Report No. AVFL-19-2 Advanced Alternative and Renewable Diesel Fuels: Detailed Characterization of Physical and Chemical Properties; Coordinating Research Council: Alpharetta, GA, 2013.

(65) Luning Prak, D. J.; Ye, S.; McLaughlin, M.; Cowart, J. S.; Trulove, P. Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Selected Ternary Mixtures of Butylcyclohexane + a Linear Alkane (Hexadcane or Dodecane) + an Aromatic Compound (Toluene, n-Butylbenzene, or n-Hexylbenzene). J. Chem. Eng. Data 2017, 62, 3452−3472. (66) Osecky, E. M.; Bogin, G. E.; Villano, S. M.; Ratcliff, M. A.; Luecke, J.; Dean, A. M.; Zigler, B. T. Investigation of Iso-octane Ignition and Validation of a Multizone Modeling Method in an Ignition Quality Tester. Energy Fuels 2016, 30, 9761−9771. (67) Bogin, G.; Dean, A.; Ratcliff, M.; Luecke, J.; Zigler, B. Expanding the Experimental Capabilities of the Ignition Quality Tester for Autoigniting Fuels. SAE Int. J. Fuels Lubr. 2010, 3, 353−367. (68) Reddemann, M. A.; Mathieu, F.; Marin, D.; Kneer, R. The influence of fuel properties on spray propogation, atomization, and evaporation. ILASS- Europe 2010, 23rd Annual Conference on Liquid Atomization and Spray systems, Brno, Czech Republic, September 2010. (69) Hamilton, L.; Luning Prak, D.; Cowart, J. Predicting the Physical and Chemical Ignition Delays in a Military Diesel Engine Running n-Hexadecane Fuel. J. Eng. Gas Turbines Power 2014, 136, 071505-1−071505-7. (70) Cowart, J.; Raynes, M.; Hamilton, L.; Luning Prak, D.; Mehl, M.; Pitz, W. An experimental and modeling study into using normal and isocetane fuel blends as a surrogate for a Hydro-Processed Renewable Diesel (HRD) Fuel. J. Energy Resour. Technol. 2014, 136, 032202-1−032202-9. (71) Cowart, J. S.; Luning Prak, D. J.; Hamilton, L. J. The effects of fuel injection pressure and fuel type on the combustion characteristics of a diesel engine. J. Eng. Gas Turbines Power 2015, 137, 10151-1− 101501-9. (72) Payri, R.; Viera, J. P.; Gopalakrishnan, V.; Szymkowicz, P. G. The effect of nozzle geometry over the evaporative spray formation for three different fuels. Fuel 2017, 188, 645−660. (73) Yu, J.; Ju, Y.; Gou, X. Surrogate fuel formulation for oxygenated and hydrocarbon fuels by using the molecular structure and functional groups. Fuel 2016, 166, 211−218. (74) Yanowitz, J.; Ratcliff, M. A.; McCormick, R. L.; Taylor, J. D.; Murphy, M J. Compendium of Experimental Cetane Numbers; National Renewable Energy Lab Technical Report NREL/TP-5400-67585; February 2017. (75) Haas, F. M.; Ramcharan, A.; Dryer, F. L. Relative reactivities of the isomeric butanols and ethanol in an ignition quality tester. Energy Fuels 2011, 25, 3909−3916. (76) Baumgardner, M. E.; Sarathy, S. M.; Marchese, A. J. Autoignition characterization of primary reference fuels and nheptane/n-butanol mixtures in a constant volume combustion device and homogeneous charge compression engine. Energy Fuels 2013, 27, 7778−7789. (77) Kuszewski, H.; Jaworski, A.; Ustrzycki, A.; Lejda, K.; Balawender, K.; Wos, P. Use of a constant volume combustion chamber to examine the properties of autoignition and derived cetane number of mixtures of diesel fuel and ethanol. Fuel 2017, 200, 564− 575. (78) Naser, N.; Yang, S. Y.; Kalghatgi, G.; Chung, S. H. Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester. Fuel 2017, 187, 117−127. (79) Battin-Leclerc, F.; Warth, V.; Bounaceur, R.; Husson, B.; Herbinet, O.; Glaude, P.-A. The oxidation of large alkylbenzenes: An experimental and modeling study. Proc. Combust. Inst. 2015, 35, 349− 356. (80) Sabourin, S. W.; Boteler, C. I.; Hallett, W. L. H. Droplet ignition of approximately continuous liquid mixtures of n-paraffins and n-alkyl aromatics. Combust. Flame 2016, 163, 326−336. (81) Darcy, D.; Nakamura, H.; Tobin, C. J.; Mehl, M.; Metcalfe, W. K.; Pitz, W. J.; Westbrook, C. K.; Curran, H. J. An experimental and modeling study of surrogate mixtures of n-propyl- and n-butylbenzene in n-heptane to simulate n-decylbenzene ignition. Combust. Flame 2014, 161, 1460−1473. J



Article

(82) Koivisto, E.; Ladommatos, N.; Gold, M. Compression ignition and pollutant emission of large alkylbenzenes. Fuel 2016, 172, 200− 208. (83) Darcy, D.; Tobin, C. J.; Yasunaga, K.; Simmie, J. M.; Wurmel, J.; Metcalfe, W. K.; Niass, T.; Ahmed, S. S.; Westbrook, C. K.; Curran, H. J. A high pressure shock tube study of n-propyl benzene oxidation and its comparison to butylbenzene. Combust. Flame 2012, 159, 2219− 2232. (84) Nakamura, H.; Darcy, D.; Mehl, M.; Tobin, C. J.; Metcalfe, W. K.; Pitz, W. J.; Westbrook, C. K.; Curran, H. J. An experimental and modeling study of shock tube and rapid compression machine ignition of n-butylbenzene/air mixtures. Combust. Flame 2014, 161, 49−64. (85) Roubaud, A.; Lemaire, O.; Minetti, R.; Sochet, L. R. High pressure auto-ignition and oxidation mechanisms of o-xylene, oethyltoluene, and n-butylbenzene between 600 and 900 K. Combust. Flame 2000, 123, 561−571. (86) Natelson, R. H.; Kurman, M. S.; Cernansky, N. P.; Miller, D. L. Low temperature oxidation of n-butylcyclohexane. Combust. Flame 2011, 158, 2325−2337. (87) Hong, Z.; Lam, K.-Y.; Davidson, D. F.; Hanson, R. K. A comparative study of the oxidation characteristics of cyclohexane, methylcylohexane, and n-butylcyclohexane at high temperatures. Combust. Flame 2011, 158, 1456−1468. (88) Liu, N.; Ji, C.; Egolfopoulos, F. N. Ignition of non-premixed cyclohexane and mono-alkylated cyclohexane flames. Proc. Combust. Inst. 2013, 34, 873−880. (89) Lemaire, R.; Faccinetto, A.; Therssen, E.; Ziskind, M.; Focsa, C.; Desgroux, P. Experimental comparison of soot formation in turbulent flames of diesel and surrogate diesel fuels. Proc. Combust. Inst. 2009, 32, 737−744. (90) Mathieu, O.; Djebaili-Chaumeix, N.; Paillard, C. E.; Douce, F. Experimental study of soot formation from a diesel fuel surrogate in a shock tube. Combust. Flame 2009, 156, 1576−1586. (91) Puduppakkam, K.; Naik, C. V.; Wang, C.; Meeks, E. Validation studies of a detailed kinetics mechanism for diesel and gasoline surrogate fuels. SAE Tech. Pap. Ser. 2010, Paper number 2010-010545, DOI: 10.4271/2010-01-0545. (92) Yao, T.; Pei, Y.; Zhong, B.-J.; Som, S.; Lu, T.; Luo, K. H. A compact skeletal mechanism for n-dodecane with optimized semiglobal low-temperature chemistry for diesel engine simulations. Fuel 2017, 191, 339−349. (93) Kourdis, P. D.; Bellan, J. Highly Reduced Species Mechanisms for iso-Cetane Using the Local Self-Similarity Tabulation Method. Int. J. Chem. Kinet. 2016, 48, 739−752.

K


Biobased Diesel Fuel Analysis and Formulation and Testing of

Recommend Documents