Showing papers on "Gasoline published in 2019"

Microwave vacuum pyrolysis of waste plastic and used cooking oil for simultaneous waste reduction and sustainable energy conversion: Recovery of cleaner liquid fuel and techno-economic analysis

Abstract: Microwave vacuum pyrolysis was examined and compared to conventional pyrolysis for its technical and economic feasibility in co-processing of waste plastic and used cooking oil simultaneously to generate fuel product. The pyrolysis demonstrated beneficial process features with respect to high heating rate (29 °C/min) to provide fast heating, high process temperature for extensive cracking (581 °C), short process time (20 min), and low electrical energy consumption (0.38 kWh). The combined use of microwave vacuum pyrolysis and activated carbon reaction bed produced up to 84 wt% yield of liquid oil, containing light hydrocarbons and higher heating value (49 MJ/kg) than diesel and gasoline, hence showing great promise for application as fuel. The use of activated carbon reaction bed showed beneficial effect in creating a reduction environment that prevented the oxidation or formation of oxygenated by-products. A positive synergistic effect between waste plastic and used cooking oil was also observed. The liquid oil obtained from this pyrolysis approach presented a low oxygen and nitrogen content, and free of sulphur, showing ‘cleaner’ properties with respect to reduced char residues, sludge formation, corrosiveness, degradation of oil quality, and emission of undesired SOx and NOx during its utilization in combustion process. The techno-economic analysis indicated that this pyrolysis approach showed low production cost (USD 0.25/L compared to USD 0.523/L of diesel price in Malaysia). Our results demonstrate that microwave vacuum pyrolysis is potentially economically feasible and show promise as a sustainable approach for energy conversion in providing improved process features and production of cleaner liquid fuel.

Engine combustion and emission fuelled with natural gas: A review

Abstract: Natural gas (NG) is one of the most important and successful alternative fuels for vehicles. Engine combustion and emission fuelled with natural gas have been reviewed by NG/gasoline bi-fuel engine, pure NG engine, NG/diesel dual fuel engine and HCNG engine. Compared to using gasoline, bi-fuel engine using NG exhibits higher thermal efficiency; produces lower HC, CO and PM emissions and higher NOx emission. The bi-fuel mode can not fully exert the advantages of NG. Optimization of structure design for engine chamber, injection parameters including injection timing, injection pressure and multi injection, and lean burn provides a technological route to achieve high efficiency, low emissions and balance between HC and NOx. Compared to diesel, NG/diesel dual fuel engine exhibits longer ignition delay; has lower thermal efficiency at low and partial loads and higher at medium and high loads; emits higher HC and CO emissions and lower PM and NOx emissions. The addition of hydrogen can further improve the thermal efficiency and decrease the HC, CO and PM emissions of NG engine, while significantly increase the NOx emission. In each mode, methane is the major composition of THC emission and it has great warming potential. Methane emission can be decreased by hydrogen addition and after-treatment technology.

A comprehensive review of the adsorption mechanisms and factors influencing the adsorption process from the perspective of bioethanol dehydration

Abstract: The production of bioethanol is growing, as it is been used as biofuel which is termed as a clean energy fuel. When ethanol is blended with gasoline, the octane number of the mixture increases and acts as an antiknock agent, besides releasing fewer pollutant emissions. To use as an automobile fuel when blended with gasoline, this ethanol should have less than 0.5 wt% of water. Therefore, ethanol has to be dehydrated; but it forms an azeotrope with water. In these scenarios, the implementation of conventional distillation technique is difficult and therefore unconventional techniques like extractive distillation have to be implemented. But this process leads to high operating costs, and hence researchers have investigated adsorption-based techniques. This methodology is not only very effective but also less expensive. The performance of the adsorption process depends on the type of adsorbent, its physical characteristics like particle and pore size, the phase in which it is carried and process parameters like temperature, initial concentration, and dosage. Thus, this paper presents a comprehensive review of the intrinsic characteristics of adsorbents, the effect of process parameters on adsorption efficiency and the influence of the phase of operation. Various types of isotherm and kinetic models utilized in the adsorption process are also presented in detail. Mathematical models describe the inherent mechanisms of the adsorption process; hence the governing equations like mass, energy and momentum balances for both liquid and gas phase are also reviewed.

High‐Quality Gasoline Directly from Syngas by Dual Metal Oxide–Zeolite (OX‐ZEO) Catalysis

Abstract: Despite significant efforts towards the direct conversion of syngas into liquid fuels, the selectivity remains a challenge, particularly with regard to high-quality gasoline with a high octane number and a low content of aromatic compounds. Herein, we show that zeolites with 1D ten-membered-ring (10-MR) channel structures such as SAPO-11 and ZSM-22 in combination with zinc- and manganese-based metal oxides (Zna Mnb Ox ) enable the selective synthesis of gasoline-range hydrocarbons C5 -C11 directly from syngas. The gasoline selectivity reached 76.7 % among hydrocarbons, with only 2.3 % CH4 at 20.3 % CO conversion. The ratio of isoparaffins to n-paraffins was as high as 15, and the research octane number was estimated to be 92. Furthermore, the content of aromatic compounds in the gasoline was as low as 16 %. The composition and structure of Zna Mnb Ox play an important role in determining the overall activity. This process constitutes a potential technology for the one-step synthesis of environmentally friendly gasoline with a high octane number from a variety of carbon resources via syngas.

European Regulatory Framework and Particulate Matter Emissions of Gasoline Light-Duty Vehicles: A Review

Abstract: The particulate matter (PM) emissions of gasoline vehicles were much lower than those of diesel vehicles until the introduction of diesel particulate filters (DPFs) in the early 2000s. At the same time, gasoline direct injection (GDI) engines started to become popular in the market due to their improved efficiency over port fuel injection (PFI) ones. However, the PM mass and number emissions of GDI vehicles were higher than their PFI counterparts and diesel ones equipped with DPFs. Stringent PM mass levels and the introduction of particle number limits for GDI vehicles in the European Union (EU) resulted in significant PM reductions. The EU requirement to fulfill the proposed limits on the road resulted to the introduction of gasoline particulate filters (GPFs) in EU GDI models. This review summarizes the evolution of PM mass emissions from gasoline vehicles placed in the market from early 1990s until 2019 in different parts of the world. The analysis then extends to total and nonvolatile particle number emissions. Care is given to reveal the impact of ambient temperature on emission levels. The discussion tries to provide scientific input to the following policy-relevant questions. Whether particle number limits should be extended to gasoline PFI vehicles, whether the lower limit of 23 nm for particle number measurements should be decreased to 10 nm, and whether low ambient temperature tests for PM should be included.

Detailed Speciation of Intermediate Volatility and Semivolatile Organic Compound Emissions from Gasoline Vehicles: Effects of Cold-Starts and Implications for Secondary Organic Aerosol Formation

Abstract: Over the past two decades vehicle emission standards in the United States have been dramatically tightened with the goal of reducing urban air pollution. Secondary organic aerosol (SOA) is the dominant contributor to urban organic aerosol. Experiments were conducted at the California Air Resources Board Haagen-Smit Laboratory to characterize exhaust organics from 20 gasoline vehicles recruited from the California in-use fleet. The vehicles spanned a wide range of emission certification standards. We comprehensively characterized intermediate volatility and semivolatile organic compound emissions using thermal desorption two-dimensional gas-chromatography–mass-spectrometry with electron impact (GC × GC-EI-MS) and vacuum-ultraviolet (GC × GC-VUV-MS) ionization. Single-ring aromatic compounds with unsaturated C4 and C5 substituents contribute a large fraction of the intermediate volatility organic compound (IVOC) emissions in gasoline vehicle exhaust. The analyses of quartz filters used in GC × GC-VUV-MS sho...

Investigation on Blending Effects of Gasoline Fuel with N-Butanol, DMF, and Ethanol on the Fuel Consumption and Harmful Emissions in a GDI Vehicle

Abstract: The effects of three kinds of oxygenated fuel blends—i.e., ethanol-gasoline, n-butanol-gasoline, and 2,5-dimethylfuran (DMF)-gasoline-on fuel consumption, emissions, and acceleration performance were investigated in a passenger car with a chassis dynamometer. The engine mounted in the vehicle was a four-cylinder, four-stroke, turbocharging gasoline direct injection (GDI) engine with a displacement of 1.395 L. The test fuels include ethanol-gasoline, n-butanol-gasoline, and DMF-gasoline with four blending ratios of 20%, 50%, 75%, and 100%, and pure gasoline was also tested for comparison. The original contribution of this article is to systemically study the steady-state, transient-state, cold-start, and acceleration performance of the tested fuels under a wide range of blending ratios, especially at high blending ratios. It provides new insight and knowledge of the emission alleviation technique in terms of tailoring the biofuels in GDI turbocharged engines. The results of our works showed that operation with ethanol–gasoline, n-butanol–gasoline, and DMF–gasoline at high blending ratios could be realized in the GDI vehicle without any modification to its engine and the control system at the steady state. At steady-state operation, as compared with pure gasoline, the results indicated that blending n-butanol could reduce CO2, CO, total hydrocarbon (THC), and NOX emissions, which were also decreased by employing a higher blending ratio of n-butanol. However, a high fraction of n-butanol increased the volumetric fuel consumption, and so did the DMF–gasoline and ethanol–gasoline blends. A large fraction of DMF reduced THC emissions, but increased CO2 and NOX emissions. Blending n-butanol can improve the equivalent fuel consumption. Moreover, the particle number (PN) emissions were significantly decreased when using the high blending ratios of the three kinds of oxygenated fuels. According to the results of the New European Drive Cycle (NEDC) cycle, blending 20% of n-butanol with gasoline decreased CO2 emissions by 5.7% compared with pure gasoline and simultaneously reduced CO, THC, NOX emissions, while blending ethanol only reduced NOX emissions. PN and particulate matter (PM) emissions decreased significantly in all stages of the NEDC cycle with the oxygenated fuel blends; the highest reduction ratio in PN was 72.87% upon blending 20% ethanol at the NEDC cycle. The high proportion of n-butanol and DMF improved the acceleration performance of the vehicle.

Impact of exhaust gas recirculation on ignition delay times of gasoline fuel: An experimental and modeling study

Abstract: The ignition delay times of a research grade gasoline, RON95E10, are measured in a rapid compression machine and in a shock tube. The experiments are carried out for fuel/O2/Ar/N2 mixtures with two equivalence ratios of 0.77 and 1.18 at pressures between 20 and 40 bar over the temperature range of 700–1250 K. In particular, data are reported for two exhaust gas recirculation (EGR) loadings of 0 and 25% to demonstrate the impact of EGR on gasoline ignition delay times. The presented data are, to the authors’ knowledge, the first set of ignition delay times of real gasoline with EGR and at engine relevant high pressures covering the entire intermediate temperature range. A published gasoline mechanism (Cai and Pitsch, 2015) is modified as part of this study following the latest kinetic knowledge and is further used to compute the ignition delay times at the conditions experimentally investigated. The simulations employ a four-component surrogate consisting of n-heptane, iso-octane, toluene, and ethanol. It is shown that the proposed model predicts the total ignition delay times of gasoline accurately under various conditions and reflects correctly the influences of pressure, EGR, and equivalence ratio on ignition delay times, while it fails to predict the first stage ignition delay times with very high accuracy due to the neglect of the olefin and naphthene content in the surrogate formulation. Furthermore, the influence of exhaust gas addition on ignition delay times is analyzed and discussed in more detail using results from numerical simulations. The chemical impact of EGR is minor but not negligible and varies at different conditions depending on the EGR composition.

Kinetic modeling study of surrogate components for gasoline, jet and diesel fuels: C7-C11 methylated aromatics

Abstract: Kinetic mechanisms for aromatics are needed to successfully simulate the autoignition of transportation fuels using the surrogate fuel approach. An aromatic detailed kinetic mechanism that describes kinetics of C7-C11 methylated aromatics, including toluene, o-xylene, p-xylene, 1,2,4-trimethylbenzene, 1,3,5, trimethylbenzene and α−methylnaphthalene has been developed in the current study. The kinetic mechanism was built hierarchically using similar set of reaction pathways and reaction rate rules. In the mechanism developed, special emphasis is put on describing the detailed low-temperature ignition chemistry of o-xylene and 1,2,4-trimethylbenzene and, to our knowledge, this is the first attempt to do so in a detailed kinetic mechanism. In addition to kinetic modeling, new experimental data were acquired for toluene, o-xylene, and 1,2,4-trimethylbenzene using a rapid compression machine at low-to-intermediate temperatures and engine relevant pressures. In addition, the mechanism has been compared against data sets from the literature covering ignition delay times, flame speeds, and speciation profiles measured in a jet-stirred reactor and flow reactor. Good agreement is observed between the mechanism predictions and the experimental data. Kinetic analysis demonstrated the importance of including the low temperature chemistry of the benzylperoxy radicals to accurately capture the ignition propensity of o-xylene and 1,2,4-trimethylbenzene at low-to-intermediate temperatures and high pressures. The kinetic mechanism developed in the current study can be used for surrogate modeling of gasoline, jet and diesel fuels.

NH3 as a transport fuel in internal combustion engines: A technical review

Abstract: Ammonia (NH3) is an excellent hydrogen (H2) carrier that is easy to bulk manufacture, handle, transport, and use. NH3 is itself combustible and could potentially become a clean transport fuel for direct use in internal combustion engines (ICEs). This technical review examines the current state of knowledge of NH3 as a fuel in ICEs on its own or in mixtures with other fuels. A particular case of interest is to partially dissociate NH3 in situ to produce an NH3/H2 mixture before injection into the engine cylinders. A key element of the present innovation, the presence of H2 is expected to allow easy control and enhanced performance of NH3 combustion. The key thermochemical properties of NH3 are collected and compared to those of conventional and alternative fuels. The basic combustion characteristics and properties of NH3 and its mixtures with H2 are summarized, providing a theoretical basis for evaluating NH3 combustion in ICEs. The combustion chemistry and kinetics of NH3 combustion and mechanisms of NOx formation and destruction are also discussed. The potential applications of NH3 in conventional ICEs and advanced homogenous charge compression ignition (HCCI) engines are analyzed.