Experimental investigation of pilot-fuel combustion in dual-fuel engines, Part 1: Thermodynamic analysis of combustion phenomena

Low natural gas prices have made the fuel an attractive alternative to diesel and other common fuels, particularly in applications that consume large quantities of fuel. The North American rail industry is examining the use of locomotives powered by dual fuel engines to realize savings in fuel costs. These dual fuel engines can substitute a large portion of the diesel fuel with natural gas that is premixed with the intake air. Engine knock in traditional premixed spark-ignited combustion is undesirable but well characterized by the Methane Number index, which quantifies the propensity of a gaseous fuel to autoignite after a period of time at high temperature. Originally developed for spark-ignited engines, the ability of the methane number index to predict a fuel’s “knock” behavior in dual fuel combustion is not as fully understood. The objective of this effort is to evaluate the ability of an existing methane number algorithm to predict rapid combustion in a dual fuel engine. Sets of specialized natural gas fuel blends that, according to the MWM methane number algorithm, should have similar knock characteristics are tested in a dual fuel engine and induced to experience rapid combustion. Test results and CFD analysis reveal that rapid or aggressive combustion rates happen late in the dual fuel combustion event with this engine hardware configuration. The transition from normal combustion to late rapid combustion is characterized by changes in the heat release rate profiles. In this study, the transition is also represented by a shift in the crank angle location of the combustion’s peak heat release rate. For fuels of similar methane number that should exhibit similar knock behavior, these transitions occur at significantly different relative air-fuel ratios, demonstrating that the existing MWM methane number algorithm, while excellent for spark-ignited engines, does not fully predict the propensity for rapid combustion to occur in a dual fuel engine within the scope of this study. This indicates that physical and chemical phenomena present in rapid or aggressive dual fuel combustion processes may differ from those in knocking spark-ignited combustion. In its current form a methane number algorithm can be used to conservatively rate dual fuel engines. It is possible that derivation of a new reactivity index that better predicts rapid combustion behavior of the gaseous fuel in dual fuel combustion would allow ratings to be less conservative.

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Experimental Investigation of Applying Raw Fuel Injection Technique for Reducing Methane in Aftertreatment of Diesel Dual Fuel Engines Operating under Medium Load Conditions

10.4271/2011-01-2093 ◽

2011 ◽

Cited By ~ 3

Author(s):

Anirut Noipheng ◽

Napumee Waitayapat ◽

Tanet Aroonsrisopon ◽

Ekathai Wirojsakunchai ◽

Thummarat Thummadetsak ◽

...

Keyword(s):

Experimental Investigation ◽

Fuel Injection ◽

Dual Fuel ◽

Injection Technique ◽

Dual Fuel Engines ◽

Load Conditions

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THERMODYNAMIC ANALYSIS OF ELECTRIC POWER PRODUCTION TECHNOLOGIES IN COGENERATION SYSTEMS ON FPSO AIMING TO REDUCE CO2 EMISSIONS

Revista de Engenharia Térmica ◽

10.5380/reterm.v20i1.80454 ◽

2021 ◽

Vol 20 (1) ◽

pp. 58

Author(s):

A. G. Gallego ◽

A. C. C. Souza ◽

P. H. Morais ◽

M. Modesto

Keyword(s):

Natural Gas ◽

Thermodynamic Analysis ◽

Gas Turbines ◽

Maximum Load ◽

Dual Fuel ◽

Complex Structures ◽

Oil Platforms ◽

Electric Power Production ◽

Dual Fuel Engines ◽

Production Technologies

Oil platforms are complex structures used to host workers and equipmentneeded in offshore exploration. This study focuses on the platform's heatand electricity cogeneration plant, which supplies a process heat exchangersnet, and provides the necessary electricity for all the equipment used for theprocess and worker's accommodation in the platform. The platform demandwith maximum load is 75 MW, which could be achieved using four gasturbines (25 MW each), one of which is kept for backup purposes or usingsix dual-fuel engines diesel/natural gas (15 MW each), one of which is alsokept for backup purposes. Therefore, the thermodynamic analysis wasperformed - considering five specific demand points of the platform -comparing the two traditional configurations (gas turbines and dual-fuelengines diesel/natural gas) and a combined configuration. The combinedconfiguration is composed of three gas turbines and two dual-fuel enginesdiesel/natural gas (one of the gas turbines kept for backup purposes). Theconfigurations presented respectively 35.5%, 48.4% and 42.6% at highestoverall efficiency; 611.34 g/kWh, 373.45 g/kWh, 472.74 g/kWh at lowestCO2 emissions considering full attendance of electrical and thermaldemands. The configurations using only gas turbines and the combinedfully attended the thermal demand of the platform without using auxiliarypieces of equipment. Therefore, it was possible to observe that thecombined configuration presented several advantages concerning isolatedsystems, proving to be an excellent option for sustainable energygeneration, reducing emissions of polluting gases and greater flexibility ofits operation concerning to configuration only with turbines, and physicaloccupation in relation to configuration only with engines.

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Experimental investigation on the performance and emissions characteristics of ethanol/diesel dual-fuel combustion

Fuel ◽

10.1016/j.fuel.2018.02.002 ◽

2018 ◽

Vol 220 ◽

pp. 72-79 ◽

Cited By ~ 20

Author(s):

Jeongwoo Lee ◽

Sunyoup Lee ◽

Seokhwan Lee

Keyword(s):

Experimental Investigation ◽

Fuel Combustion ◽

Dual Fuel ◽

Performance And Emissions ◽

Dual Fuel Combustion

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Experimental investigation of ethanol/diesel dual-fuel combustion in a heavy-duty diesel engine

Fuel ◽

10.1016/j.fuel.2020.117867 ◽

2020 ◽

Vol 275 ◽

pp. 117867 ◽

Cited By ~ 4

Author(s):

Jinlin Han ◽

L.M.T Somers ◽

Roger Cracknell ◽

Arndt Joedicke ◽

Robert Wardle ◽

...

Keyword(s):

Experimental Investigation ◽

Diesel Engine ◽

Fuel Combustion ◽

Dual Fuel ◽

Heavy Duty ◽

Heavy Duty Diesel Engine ◽

Dual Fuel Combustion ◽

Heavy Duty Diesel

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Effects of N-Butanol Content on the Dual-Fuel Combustion Mode With CNG at Two Engine Speeds

Volume 1: Large Bore Engines; Fuels; Advanced Combustion ◽

10.1115/icef2018-9595 ◽

2018 ◽

Author(s):

Xiangyu Meng ◽

Wuqiang Long ◽

Yihui Zhou ◽

Mingshu Bi ◽

Chia-Fon F. Lee

Keyword(s):

Thermal Efficiency ◽

Engine Speed ◽

Direct Injection ◽

Fuel Combustion ◽

Dual Fuel ◽

Combustion Mode ◽

Start Of Injection ◽

Wide Range ◽

Pilot Fuel ◽

Dual Fuel Combustion

Because of the potential to reduce NOx and PM emissions simultaneously and the utilization of biofuel, diesel/compressed natural gas (CNG) dual-fuel combustion mode with port injection of CNG and direct injection of diesel has been widely studied. While in comparison with conventional diesel combustion mode, the dual-fuel combustion mode generally leads lower thermal efficiency, especially at low and medium load, and higher carbon monoxide (CO) and total hydrocarbons (THC) emissions. In this work, n-butanol was blended with diesel as the pilot fuel to explore the possibility to improve the performance and emissions of dual-fuel combustion mode with CNG. Various pilot fuels of B0 (pure diesel), B10 (90% diesel/10% n-butanol by volume basis), B20 (80% diesel/20% n-butanol) and B30 (70% diesel/30% n-butanol) were compared at the CNG substitution rate of 70% by energy basis under the engine speeds of 1400 and 1800 rpm. The experiments were carried out by sweeping a wide range of pilot fuel start of injection timings based on the same total input energy including pilot fuel and CNG. As n-butanol was added into the pilot fuel, the pilot fuel/CNG/air mixture tends to be more homogeneous. The results showed that for the engine speed of 1400 rpm, pilot fuel with n-butanol addition leads to a slightly lower indicated thermal efficiency (ITE). B30 reveals much lower NOx emission and slightly higher THC emissions. For the engine speed of 1800 rpm, B20 can improve ITE and decrease the NOx and THC emissions simultaneously relative to B0.

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