An Experimental and Theoretical Evaluation of the Onboard Decomposed Methanol Spark-Ignition Engine

Pettersson, Lars J.; ̈M, Krister Sjo ̈Stro

doi:10.1080/00102209008951628

Cited by 10 publications

(9 citation statements)

References 7 publications

(8 reference statements)

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“…5%) is mixed with syngas in the synthesis of methanol. 9 By the reverse reaction of MeOH synthesis, viz., methanol decomposition, 66 syngas can be obtained in situ. For small-scale applications of syngas this often is a convenient route.…”

Section: Conversion To Products Via Syngasmentioning

confidence: 99%

Mitigation of CO₂by Chemical Conversion: Plausible Chemical Reactions and Promising Products

1996

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A critical literature analysis was conducted on the viable usage of CO 2 in the framework of the attempts to reduce the emissions of CO 2 into the atmosphere from various processes or the rate of increase of the concentration of CO 2 in the atmosphere. Applications based on the physical properties of CO 2 are summarized first. Major examples are applications in supercritical extraction, enhanced oil recovery, and use as inert gas in fire extinguishing and safety application in industry. The various possibilities of use in chemical applications are systematically discussed. CO 2 can react with several hydrocarbons and nitrogen-containing compounds (NH 3 , amines, imines). It can be used as a weak acid or as an oxidizing agent. It can be reduced electrochemically, photochemically, or chemically or by a syngas route. A variety of products can be manufactured from CO 2 , e.g., acids, alcohols, esters, lactones, carbamates, urethanes, urea derivatives, various copolymers, and polymers. In particular, polycarbonates are attractive products. Nevertheless, currently, less than 1% of the CO 2 emitted is used in chemical reactions. To reduce the emission of CO 2 substantially, only those reactions by which CO 2 is used to produce bulk chemicals are relevant, whereas those useful in the manufacture of fine chemicals are not important in this respect. CO 2 conversion to MeOH represents one of the most important options in CO 2 mitigation. MeOH can be used as additive to fuels or as a substitute for motor fuels. An increasingly important application is in the production of MTBE (methyl tert-butyl ether), DMC (dimethyl carbonate), or DME (dimethyl ether) which are major components in modern gasoline to boost octane number. An interesting application of MeOH is the usage as fuel for cars via in situ decomposition into syngas; this results in enhancement of the energy efficiency. From MeOH several useful products can be made. Another reaction of importance that has been commercialized is the so-called dry reforming in which methane reacts with CO 2 , giving synthesis gas. Some processes are commercialized and the technology is mature. An example is a process in which a mixture of biomass and fossil fuels is converted into methanol and carbon which is stored. It is obvious that thermodynamically most processes using CO 2 are not favorable for CO 2 mitigation. This does not imply that processes are never feasible. Special situations do exist where the usage of CO 2 in chemical applications is attractive. Examples are processes where CO 2 is available at a high temperature, where an external heat source is present without a good outlet for the heat, processes where CO 2 leads to the right stoichiometry or reaction environment. In these cases a high potential for an efficient process exists. An elegant example is "chemical cooling" of hot gases in the chemical process industry. A promising application is the direct substitution of certain chemicals by a reaction product of CO 2 ; an example is the replacement of the hazardous phosge...

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Section: Conversion To Products Via Syngasmentioning

confidence: 99%

Mitigation of CO₂by Chemical Conversion: Plausible Chemical Reactions and Promising Products

1996

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“…The change in the MER explained for a small improvement in engine efficiency with the dissociated methanol compared to the neat methanol at λ close to 1 [19]. A bigger difference in the efficiency can be seen at a highly diluted condition (lean burn or EGR dilution), as in [20,21]. 40%.…”

Section: Idealized Efficiencymentioning

confidence: 94%

“…However, the enhancement was small (3-7%) if it was compared to the efficiency that could be obtained with an engine operated on pure methanol, which itself is smaller than the change in LHV of dissociated methanol [19]. Work was also done on decomposed methanol at lean conditions, and showed a significant improvement in efficiency compared to neat methanol [20,21].…”

Section: Introductionmentioning

confidence: 97%

Exploring the potential of reformed-exhaust gas recirculation (R-EGR) for increased efficiency of methanol fueled SI engines

Nguyen

Sileghem

Verhelst

2019

Fuel

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Methanol is a promising fuel for spark ignition engines because of its high octane number, high octane sensitivity, high heat of vaporization and high laminar flame speed. To further boost the efficiency of methanol engines, the use of waste heat for driving fuel reforming was considered. This study explores the possibility of the reformed-exhaust gas recirculation (R-EGR) concept for increased efficiency of methanol engines. A simple Otto cycle calculation and a more detailed gas dynamic engine simulation are used to evaluate that potential. Both methodologies point to an enhancement in engine efficiency with fuel reforming compared to conventional EGR but not as much as the increase in lower heating value of the reforming product would suggest. A gas dynamic engine simulation shows a shortening of the flame development period and the combustion duration in line with the expected behavior with the hydrogen-rich reformer product gas. However, the heat loss increases with the presence of hydrogen in the reactants. The improvement of brake thermal efficiency is mainly attributed to the reduction of pumping work. The R-EGR concept is also evaluated for ethanol and iso-octane. As the reforming fraction increases, the efficiency of ethanol and iso-octane fueled engines rises faster than for the methanol engines due to a higher enhancement of exergy in their reforming products.

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“…During the 1980s–1990s, some studies about the use of decomposed methanol as a fuel for SI engines were done at the Royal Institute of Technology–KTH. They concluded that the engine could start at −30 °C and the engine efficiency increases by 15%–20%, relative to neat methanol, with the presence of hydrogen-rich gas (syngas). − Brinkman and Stebar performed an experimental study to compare the engine efficiency and fuel consumption with methanol and decomposed methanol at a varied compression ratio and equivalence ratio. At the same compression ratio and equivalence ratio, although the LHV increased by ∼13%, the reduction of fuel consumption for decomposed methanol was ∼3%–7%, compared to methanol.…”

Section: Introductionmentioning

confidence: 99%

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

Nguyen

Verhelst

2017

Energy Fuels

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The current work investigates the flame structure and the propagation of premixed laminar flame fronts for mixtures of diluted methanol−air enriched by fuel reforming products under spark ignition engine conditions. Two engine concepts were investigated: one with external fuel reforming (EFR) and one with reformed exhaust gas recirculation (R-EGR).Here, the fuel reformate (or syngas) is a mixture of H 2 , CO, and CO 2 with a CO selectivity of 6.5%, which is used to represent the products of methanol steam reforming over a Cu−Mn/Al foam catalyst. The simulations were exercised over a wide range of dilution level and unburned gas temperature at 40 bar with a skeletal chemical kinetic mechanism using zero/one-dimensional codes. Two types of dilutionair and EGRwere compared at the same fuel-to-charge equivalence ratio (ϕ′). The results showed that the knock limit for spark-ignited operation is extended with rising dilution levels, especially when diluted by an R-EGR mixture. Syngas addition also leads to a reduced knock tendency. At the knock limit, the fraction of heat released by autoignition is greater at a higher dilution rate. At the lower flammability limit, the stable flame propagation range is expanded to a lower unburned gas temperature when using air dilution. Under stoichiometric conditions, dilution with an R-EGR mixture is recommended for partial load operation, because it provides a stable flame at high dilution levels. The influence of gas properties were also investigated, where a shorter ignition delay after compression was observed with a leaner mixture. The ignition delay increased with a higher EGR ratio, especially in the case of the R-EGR mixture. Therefore, the knock tendency increases with a leaner mixture. However, the knock ringing intensity decreases if the mixture is diluted by air. A mixture diluted by R-EGR can reduce the knock tendency, compared to the two EGR dilution cases, and can decrease the knock ringing intensity, compared to the two air dilution cases at high dilution ratios.

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An Experimental and Theoretical Evaluation of the Onboard Decomposed Methanol Spark-Ignition Engine

Cited by 10 publications

References 7 publications

Mitigation of CO₂by Chemical Conversion: Plausible Chemical Reactions and Promising Products

Mitigation of CO₂by Chemical Conversion: Plausible Chemical Reactions and Promising Products

Exploring the potential of reformed-exhaust gas recirculation (R-EGR) for increased efficiency of methanol fueled SI engines

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

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An Experimental and Theoretical Evaluation of the Onboard Decomposed Methanol Spark-Ignition Engine

Cited by 10 publications

References 7 publications

Mitigation of CO2by Chemical Conversion: Plausible Chemical Reactions and Promising Products

Mitigation of CO2by Chemical Conversion: Plausible Chemical Reactions and Promising Products

Exploring the potential of reformed-exhaust gas recirculation (R-EGR) for increased efficiency of methanol fueled SI engines

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

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Product

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Mitigation of CO₂by Chemical Conversion: Plausible Chemical Reactions and Promising Products

Mitigation of CO₂by Chemical Conversion: Plausible Chemical Reactions and Promising Products