Blending Octane Number Research Articles

A New Approach to Determining the Blending Octane Number of Gaseous Components of Motor Gasolines

A New Approach to Determining the Blending Octane Number of Gaseous Components of Motor Gasolines

Tert-Butyl Ethers of Renewable Diols as Oxygenate Additives to Automobile Gasolines. Part II: Ethers of Ethylene Glycol and 2,3-Butanediol

The results obtained in the second part of the study of vicinal (tert-butoxy)alkanols as additives to automobile gasolines are presented. Mono-tert-butyl ethers of ethylene glycol (ETBE) and 2,3-butanediol (BTBE) were prepared by direct acid-catalyzed alkylation of the corresponding diols with tert-butanol. The substances obtained were characterized by main physical properties (density, viscosity, boiling point, crystallization point, specific heat of combustion) and were studied as additives to automobile gasolines. The effect of ether additives on the main physicochemical properties of gasolines (fractional composition, saturated vapor pressure, concentration of actual resins, knock resistance), including ethanol-containing gasolines, was studied. The mean research/motor blending octane numbers for ETBE and BTBE were 130/103 and 115/97, respectively. Inclusion of ETBE/BTBE into the formulations of ethanol-containing gasolines allowed the cloud point to be considerably reduced without unambiguous synergistic effect on the knock resistance.

Blending Carbon Intensity for Ethanol in Gasoline

<div>Greenhouse gas emissions reduction from the light-duty transportation fleet is urgent and should address both electric and conventional powertrain technologies. Internal combustion engines will continue to be employed for vehicle propulsion and fleet turnover is slow, encouraging reduction of carbon content in gasoline. Currently ethanol, a renewable fuel, is blended at the 10% level into petroleum to produce finished market gasoline. Ethanol enables a less carbon-intensive petroleum blendstock composition, providing for additional reduction, but this is often overlooked in studies. Carbon intensity, as a ratio of CO<sub>2</sub> mass to heat released upon combustion, is a measure of well-to-wheels greenhouse gas production. The well-to-wheels carbon intensity of ethanol does not include its chemical carbon content because it arises from a renewable source, but does consider all upstream farming, production, and transportation carbon impacts. The well-to-wheels carbon intensity of the petroleum fraction includes the chemically bound carbon, as well as production and transportation impact. Carbon intensity modeling results for ethanol vary widely, primarily due to differences in land-use change assessment. The GREET model has gained wide acceptance and provides a present-day carbon intensity for pure ethanol that is 43% lower than for petroleum gasoline. Ethanol exhibits a high blending octane number so that the petroleum component has a lower octane rating than required for purely petroleum gasoline. Fuel trends and modeling suggest that a 10% (by volume) ethanol addition enables a 9% reduction of aromatics, which have a high carbon intensity. If the carbon reduction benefits of the aromatic reduction are assigned to the agency of the ethanol, the blending carbon intensity of ethanol is 56% lower than for petroleum gasoline. Increase in ethanol blending therefore offers substantial immediate climate change reduction.</div>

Tert-Butyl Ethers of Renewable Diols as Oxygenate Additives to Automobile Gasolines. Part II: Ethers of Ethylene Glycol and 2,3-Butanediol

The results obtained in the second part of the study of vicinal (tert-butoxy)alkanols as additives to automobile gasolines are presented. Mono-tert-butyl ethers of ethylene glycol (ETBE) and 2,3-butanediol (BTBE) were prepared by direct acid-catalyzed alkylation of the corresponding diols with tert-butanol. The substances obtained were characterized by main physical properties (density, viscosity, boiling point, crystallization point, specific heat of combustion) and were studied as additives to automobile gasolines. The effect of ether additives on the main physicochemical properties of gasolines (fractional composition, saturated vapor pressure, concentration of actual resins, knock resistance), including ethanol-containing gasolines, was studied. The mean research/motor blending octane numbers for ETBE and BTBE were 130/103 and 115/97, respectively. Inclusion of ETBE/BTBE into the formulations of ethanol-containing gasolines allowed the cloud point to be considerably reduced without unambiguous synergistic effect on the knock resistance.

A new approach to determining the blending octane number of gaseous components of motor gasolines

The octane number for gaseous components (GC) is currently determined using the calculation method proceeding from the hydrocarbon composition. The method provides determination of the research octane number (RON) only. A discrepancy between the actual and predicted values of the octane number thus determined leads to an overestimated introduction of these components into the fuel which results in the reduced fuel performance and economic indicators of the production. In this regard, the development of a new approach to the determination of the blending octane number of low-boiling components is extremely important for designing optimal formulations of motor fuels. A method for determining the blending octane numbers (both RON and MON) of motor gasoline gaseous components has been improved due to preliminary sample preparation by bubbling which provided taking into account the proportion of involving fractions of C4 hydrocarbon and pentane-amylene along with the chemical nature of the base fuel components. It is shown that the value of the blending octane number for gaseous components depends on the hydrocarbon composition of the base component. Application of the developed method to determining the blending octane number of gaseous components of motor fuels allowed us to obtain optimal formulations of gasoline with the involvement of low-boiling by-products and increased the accuracy of forecasting the composition of fuels thus improving the economic performance of the production.

Эффективность метил-трет-бутилового эфира и этинилциклогексанола на повышение октанового числа бензиновых композиций (бензина с установки замедленного коксования + риформинг)

Современным автомобилям требуется высокооктановое топливо с антидетонационными свойствами, характеризующееся октановыми числами двигателя 92, 95 и 98. Высокие антидетонационные характеристики достигаются либо путем глубокой модификации бензинов с использованием процессов каталитического крекинга, изомеризации, алкилирования, либо путем введения в топливо специальных высокооктановых присадок. Основной мировой тенденцией в улучшении экологических и эксплуатационных свойств автомобильных бензинов является использование многофункциональных присадок, в основном оксигенатов - кислородсодержащих веществ (спиртов, кетонов, эфиров и др.). Присутствие кислорода в молекуле оксигенатного топлива позволяет снизить вредные выбросы монооксида углерода на 30%, а несгоревших углеводородов - на 15%. В представленной работе было исследовано влияние двух таких компонентов - этинилциклогексанола (ЭЦГ) и метил-трет-бутилового эфира (МТБЭ) - на повышение октанового числа бензиновых смесей в соотношениях 40:60 и 20:80 бензина установки замедленного коксования (УЗК) и бензина риформинга. Показано, что использование ЭЦГ как присадки эффективнее, чем МТБЭ, для увеличения октанового числа бензиновых композиций.

Unraveling the octane response of gasoline/ethanol blends: Paving the way to formulating gasoline surrogates

Ethanol is widely used as a gasoline octane booster, and yet, its blending response is not fully understood. Blending ethanol with gasoline most often leads to a synergistic effect (higher than expected relative to linear blending), but can also lead to a linear or antagonistic blending (lower than expected relative to linear blending). To address the knowledges gap in ethanol blending, this study provides new research octane number (RON) and motor octane number (MON) measurements of ethanol blended with various gasoline surrogates. The first set of blends are ternary mixtures, designed to study the interactions between primary reference fuels (PRFs) and certain gasoline components when blended with ethanol. These gasoline components are 1-hexene, 1,2,4-trimethylbenzene and cyclopentane, which, represents the olefin, aromatic and naphthenes classes in commercial gasoline fuels, respectively. The second set represents multicomponent surrogates for Fuels for Advanced Combustion Engines (FACE) gasolines, developed in our previous work (Badra et al., Applied Energy 2017 p. 778-793). This study developes an octane blending model of ethanol/gasoline surrogates that utilize the new measurements along with datasets available in literature. The model consists of the conventional linear by ethanol molar fraction correlation, with the addition of non-linearity terms that depend on base fuel properties, namely, the octane sensitivity and the mole fraction of gasoline components. The model can predict the octane numbers (RON and MON) of blends containing gasoline surrogates composed of n-heptane, n-pentane, iso-octane, iso-pentane, toluene, 124-trimethylbenzene, cyclopentane, cyclohexane (for RON only) and 1-hexene. To ensure the generality of the developed model and avoid over-fitting, the model is trained using 85% of the available dataset while the remaining measurements have been used to test the model. The proposed model outperforms many ethanol blending models available in literature with 87% of the RON and 83% of the MON measurements being within the reproducibility limits. This model can be integrated to the process of designing gasoline surrogates that contain ethanol.

Quantification of gasoline-ethanol blend emissions effects

ABSTRACT Emissions levels from current gasoline spark-ignited engines are low, and emissions changes associated with the blending of ethanol into gasoline are small and difficult to quantify. Addition of ethanol, with a high blending octane number, allows a reduction in aromatics in market gasoline. Blending behavior of ethanol is nonlinear, altering the distillation curve, including the 50% temperature point, T50. Increase in gasoline direct injection (GDI) engine technology in the fleet challenges ability of older models based on port fuel injection (PFI) results to predict the overall air quality impact of ethanol blending. Five different models derived from data collected through U.S. Environmental Protection Agency Energy Policy Act (EPAct) programs were used to predict LA92 Phase 1 particulate matter (PM) emissions for summer regular (SR) E0 (gasoline with 0% ethanol by volume), E10 (gasoline with 10% ethanol) and E15 (gasoline with 15% ethanol). Substantial reductions of PM for E10 and E15 relative to E0 were predicted when aromatics were displaced by ethanol to maintain octane rating. SR E0 and E10 were also matched to linear combinations of EPAct fuels and results showed a 35% PM reduction for SR E10 relative to SR E0. For GDI vehicles the Coordinating Research Council (CRC) E-94-3 study found that E10 had 23% or 29% PM increase. However, CRC E-129 found an E10 PM reduction of 10% when one E0 fuel and its splash blended (SB) E10 were compared. Both CRC project E-129 SB data and fuel triplets selected from the EPAct study showed variation for E15 emissions, although E-129 suggests that E15 in GDI offers about a 25% reduction of PM with respect to E0. Overall, data suggest that ethanol blending offers a modest to a substantial reduction of cold-start PM mass if aromatic levels of the finished products are reduced in response to ethanol addition. Implications: Studies of exhaust emissions effects of ethanol blending with gasoline vary in conclusions. Blending properties are nonlinear. Modeling of real-world emissions effects must consider all fuel composition adjustments and property changes associated with ethanol addition. Aromatics are reduced in E10 or E15, compared with E0, and distillation changes. PFI-derived models show reductions in cold-start PM for expected average E10 versus E0 pump fuel, due to reduced aromatic content. Relative emissions effects from older technology (PFI) engines do not predict newer engine (GDI) results reliably, but recent GDI data show reduced cold-start PM when ethanol displaces aromatics.

Understanding the synergistic blending octane behavior of 2-methylfuran

The autoignition kinetics of hydrocarbons is an important criterion for selecting fuels for piston reciprocating engines, and it can be determined by relative performance to mixtures of alkanes, n-heptane and iso-octane, under certain standardized operating conditions. 2-methylfuran is a potential biofuel candidate, whose autoignition chemistry is markedly different from alkanes. Its octane behavior when blended with paraffins also shows a marked difference. The blending octane behavior of a fuel is characterized by its Blending Octane Number (BON). The BON of 2-methylfuran was extensively characterized in this work. 2-methylfuran's BON was mapped from experimental ignition delay times measured in a constant volume combustion chamber using established correlations. The effect on BON was studied depending on the RON of the base fuel into which 2-methylfuran was blended, as well as the quantity of 2-methylfuran blended. BON of 2-methyfuran was greater than its RON by a factor of four or more for some blends studied. BON reduced with increasing RON of the base fuel, as well as with increasing quantity of 2-methylfuran blended. A chemical kinetic model was created by integration of well validated sub-models for the blend components, and then used to explain the chemical kinetics leading to the extremely high BON values of 2-methylfuran. The synergetic anti-knock blending effect of 2-methylfuran is partially due to its physical properties leading to a greater molar fraction per volume fraction in the blend compared to iso-octane. Analysis using chemical kinetic model revealed that the chemical action behind 2-methylfuran's blending octane behavior was due to its ability to quench OH radicals which are important to the low-temperature oxidation chemistry of alkanes. This quenching effect is achieved due to the more rapid reaction rate of 2-methylfuran with OH radical compared to iso-octane, followed by the immediate conversion of the adduct shifting the equilibrium towards the product.

Catalytic pyrolysis of Napier grass with nickel-copper core-shell bi-functional catalyst

Nickel-copper (Ni-Cu) core-shell catalysts supported on phosphorus-modified carbon microspheres (mCMs) were prepared at three Ni/Cu mass ratios, and applied to the catalytic pyrolysis of Napier grass (Pennisetum purpureum) under atmospheric pressure. The catalytic pyrolysis was carried out inside a custom-built one-shot two-stage fixed-bed reactor. The catalyst structure was confirmed by X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. Remarkably, the Ni-Cu/mCM catalysts increased the produced alkyl-phenols by up to fourfold, and these products are an excellent gasoline blend stock due to their high blending octane number. At the same time, the mass of undesired compounds in the bio-oil including alcohols, ketones, and furan were markedly decreased compared to the case without a catalyst. The oxygen content of the bio-oil was reduced by up to 24 % compared to the non-catalytic case. The hydrogen/carbon and oxygen/carbon molar ratios were also improved after all catalytic treatments. Finally, a reaction mechanism was proposed, including the pathways of oxygen removal through dehydration, decarbonylation, and dealkoxylation. The presence of NiO in the Ni-Cu/mCM catalyst promoted the alkylation reaction to yield more alkyl-phenols.

Determination of the Optimum formula for Composite Motor Gasoline Octane Number Blending Enhancer

To decrease the dependency of producing high octane number gasoline on the catalytic processes in petroleum refineries and to increase the gasoline pool, the effect of adding a suggested formula of composite blending octane number enhancer to motor gasoline composed of a mixture of oxygenated materials (ethanol and ether) and aromatic materials (toluene and xylene) was investigated by design of experiments made by Mini Tab 15 statistical software. The original gasoline before addition of the octane number blending enhancer has a value of (79) research octane number (RON). The design of experiments which study the optimum volumetric percentages of the four variables, ethanol, toluene, and ether and xylene materials leads to 30 experiments. The results obtained show that RON can reach a value of 103.1 (30.5% RON improvement) when a formula of composite octane number blending enhancer containing a volumetric percentage of 15, 25, 25 volumetric percent of ethanol, toluene and xylene respectively. The cost study in comparison with the price of high octane number gasoline sold in Iraq show that this formula has a high cost of 2050 Iraqi Dinar (IQD)/liter gasoline, while the formula of composite octane number blending enhancer containing 15% volumetric percentage of Ethanol only leading to gasoline of 89.6 RON (13.4 % ON improvement) gave minimum cost of 300 IQD / liter gasoline for the blend of octane number enhancer making the total price of the gasoline to be competitive with the high ON gasoline imported from outside Iraq. While the formula of 7.5, 12.5, 37.5 and 5% volumetric percentage of ethanol, toluene, xylene, and ether respectively have a maximum cost of 2525 IQD of produced gasoline of 101.3 RON (octane number improved by 28.23%).

Optimization of Blending Octane Number Premium Composition and Blending Sulfur Content Diesel Composition In Refinery I Ru IV Cilacap

Blending simulation is an important tool for blending process in oil and gas companies, for example PT. Pertamina (PERSERO) RU IV Cilacap. Crude oil is processed to become a product that can be used by the public such as Premium, Pertamax, and Pertamax Plus. In this case study, simulation blending is used to determine the optimal composition of Premium and Solar blending. Before the blending process, the Refinery Planning and Optimation division simulates the blending process by calculating so that the mixing process is in accordance with the desired quality. The results of the research showed that there was a decrease in performance units so that reformate cannot be fully entered as a Premium component and requires HOMC for blending, so that the margin in USD/barrel units decreases by 0.82 USD/barrel. In the initial condition of Solar, the margin obtained was 24846.04 thousand USD or 8.04 USD/barrel. From the optimization results, it can be seen that to obtain sulfur content of 0.3% wt, the amount of HGO was 20286.19 TON or 676.21 TPSD and the VGO amount was 11050.01 TON or 368.33 TPSD and the maximum margin that can be obtained was 28381.34 thousand USD or 9.18 USD/barrel. The margin condition in USD/barrel after the optimization of Solar sulfur content increased by 1.14 USD/barrel. At optimum conditions, the amount of Solar produced increases because it gets an additional from Solar components with high sulfur content VGO and HGO.

Approach to Accurate Octane Number Calculation for Gasoline Blending

The octane number of gasoline is one of the most important measures of gasoline quality to predict accurately the octane ratings of blending gasolines. This measured on a scale that ranges from that equivalent to isooctane (octane number of 100) to that of n-heptane (octane number of zero) octane no is effected by the saturates, aromatics, and olefins contents of gasoline. We take it as a standard and measure octane number by comparison with this standard. The accurate octane blending method will optimize the blending of gasoline components, when gasoline components are blended together, we will calculate the octane number of the blend with different octane number of the component or if the four components are of equal octane number. The blend octane number may be greater than, equal to or less than that calculated from the volumetric average of the octane numbers of the blend components, which indicates nonlinear blending. Blending would be linear if octane number of a blend was equal to that predicted by summing the octane numbers of the components in proportion to their concentrations. In practices, the discrepancies between the octane numbers of blends and the linearly predicted values have been correlated by specific empirical equations and these have been used to correct the linear predictions.

Influence of ethyl acetate addition on phase stability and fuel characteristics of hydrous ethanol-gasoline blends

Hydrous ethanol or commercial ethanol is regarded as a promising additive for gasoline. Its low cost and many other advantages, such as increasing the octane number and reduction of harmful emissions, motivate the researchers to investigate its use as an economic octane booster. The most common drawback of using hydrous ethanol as a gasoline additive is the phase separation problem. In this study, the effect of adding ethyl acetate (EA) on the phase stability, distillation curve, vapor pressure, vapor lock index and octane number of hydrous ethanol-gasoline blends was investigated. The reference fuel blends were formulated by mixing hydrous ethanol (96%) with hydrocarbon-based gasoline in different percentages (5, 10, 15 and 20 vol%). For studying the effect of ethyl acetate on the fuel specifications, it was mixed with 15% hydrous ethanol-gasoline blend in different percentage (3, 6, 9 and 12 vol%). The experimental results indicated that ethyl acetate has a good ability to increase the phase stability and the octane number of the hydrous ethanol-gasoline blends without causing adverse impacts on the other studied specifications.

Predicting Octane Number Using Nuclear Magnetic Resonance Spectroscopy and Artificial Neural Networks

Machine learning algorithms are attracting significant interest for predicting complex chemical phenomenon. In this work, a model to predict research octane number (RON) and motor octane number (MON) of pure hydrocarbons, hydrocarbon-ethanol blends, and gasoline–ethanol blends has been developed using artificial neural networks (ANNs) and molecular parameters from 1H nuclear magnetic resonance (NMR) spectroscopy. RON and MON of 128 pure hydrocarbons, 123 hydrocarbon–ethanol blends of known composition, and 30 FACE (fuels for advanced combustion engines) gasoline–ethanol blends were utilized as a data set to develop the ANN model. The effect of weight percent of seven functional groups including paraffinic CH3 groups, paraffinic CH2 groups, paraffinic CH groups, olefinic −CH═CH2 groups, naphthenic CH–CH2 groups, aromatic C–CH groups, and ethanolic OH groups on RON and MON was studied. The effect of branching (i.e., methyl substitution), denoted by a parameter termed as branching index (BI), and molecular w...

2-Methylfuran: A bio-derived octane booster for spark-ignition engines

The efficiency of spark-ignition engines is limited by the phenomenon of knock, which is caused by auto-ignition of the fuel-air mixture ahead of the spark-initiated flame front. The resistance of a fuel to knock is quantified by its octane index; therefore, increasing the octane index of a spark-ignition engine fuel increases the efficiency of the respective engine. However, raising the octane index of gasoline increases the refining costs, as well as the energy consumption during production. The use of alternative fuels with synergistic blending effects presents an attractive option for improving octane index. In this work, the octane enhancing potential of 2-methylfuran (2-MF), a next-generation biofuel, has been examined and compared to other high-octane components (i.e., ethanol and toluene). A primary reference fuel with an octane index of 60 (PRF60) was chosen as the base fuel since it closely represents refinery naphtha streams, which are used as gasoline blend stocks. Initial screening of the fuels was done in an ignition quality tester (IQT). The PRF60/2-MF (80/20 v/v%) blend exhibited longer ignition delay times compared to PRF60/ethanol (80/20 v/v%) blend and PRF60/toluene (80/20 v/v%) blend, even though pure 2-MF is more reactive than both ethanol and toluene. The mixtures were also tested in a cooperative fuels research (CFR) engine under research octane number and motor octane number like conditions. The PRF60/2-MF blend again possesses a higher octane index than other blending components. A detailed chemical kinetic analysis was performed to understand the synergetic blending effect of 2-MF, using a well-validated PRF/2-MF kinetic model. Kinetic analysis revealed superior suppression of low-temperature chemistry with the addition of 2-MF. The results from simulations were further confirmed by homogeneous charge compression ignition engine experiments, which established its superior low-temperature heat release (LTHR) suppression compared to ethanol, resulting in better blending octane numbers. This work explores and provides a chemically sound explanation for the potential of 2-MF as an octane enhancer.

Effect of ethyl acetate addition on phase stability, octane number and volatility criteria of ethanol-gasoline blends

Blending ethanol in gasoline causes problems related to volatility and phase stability of the fuel blends. Ethanol is completely miscible with water so it has high affinity to water that may be present in storage tanks or that formed due to humidity. Drop in ambient temperature influences the stability of ethanol-gasoline blends and causes phase separation to the blend. This phase separation cause disadvantages like: poor quality fuel, loss in cost, and damage to storage tanks and engine parts due to corrosion. In this work, Ethanol-blended gasolines E5, E10, E15, E20 and ethanol-free gasoline (E0) were formulated to study the effects of ethyl acetate addition on these fuels. The obtained results revealed that the addition of ethyl acetate to ethanol-gasoline blends has many advantages such as enhancing the stability of the fuel blends and improving octane number with no adverse impacts on the volatility criteria of the investigated fuel blends.

The effect of methylfurans on the physicochemical and performance characteristics of finished motor gasoline

The physicochemical and performance characteristics of blends of commercial gasoline with the promising oxygenate antiknock additives 2-methylfuran and 2,5-dimethylfuran have been studied. The key parameters determining the compliance of gasoline with the GOST R 51866-2002 (EN 228-2004) requirements have been measured. A high antiknock activity of the test compounds has been demonstrated, and blending octane numbers have been calculated. It has also been found that the addition of 2-methylfuran and 2,5-dimethylfuran to gasoline substantially deteriorates its oxidation stability and increases gum content.

New methods for the preparation of high-octane components from catalytic cracking olefins

A new method has been suggested for the preparation of high-octane components from the butane–butylene fraction (BBF) in two stages. At the first stage, the BBF olefins are oxidized with N2O into carbonyl compounds with high selectivity without forming the products of deep oxidation and water. The process occurs in the gas phase in a flow reactor without using a catalyst at a temperature of 400°C and a pressure of 2 MPa with high conversion of both olefins and nitrous oxide. The blending octane number of the oxidation product is 118–133 (RON) and 99–104 (MON). At the second stage, the mixture of carbonyl compounds is hydrogenated with hydrogen in the presence of the Ni/Al2O3 catalyst. The hydrogenation occurs at 150–160°C in a flow reactor in the gas phase. The aldehydes are completely transformed into alcohols, while the ketones can remain in the product under certain conditions. The blending octane number of the hydrogenation product is 111–112 (RON) and 95–96 (MON), which is smaller than for the BBF oxidation product, but larger than for the alkylate obtained in the course of conventional butene alkylation with isobutane (RON is 95–97 and MON is 93–95). Synthesis of high-octane components by this procedure can be useful in practice, especially in productions with huge release of nitrous oxide.

Evaluation of accuracy of literature gasoline blending models to predict octane numbers of gasoline blends

ABSTRACTThe gasoline blending prediction models available in the open literature: Linear method, Ethyl method, Stewart method, Zahed method, and Twu method were tested on 25 gasoline blends prepared from 14 components used by LUKOIL Neftohim Burgas (LNB) refinery to produce commercial gasoline grades. The performed tests with these models showed prediction accuracy outside of the acceptable ASTM D 2699 and ASTM D 2700 reproducibility limits. However, the LNB-modified regression model of Zahed method turned out to predict RON and MON of studied gasoline blends with accuracy equivalent to the reproducibility of the standard methods for measurement of RON and MON.