An experimental study on MILD combustion of prevaporised liquid fuels

Ye, Jingjing; Medwell, Paul R.; Varéa, Emilien; Kruse, Stephan; Dally, Bassam B.; Pitsch, Heinz

doi:10.1016/j.apenergy.2015.04.019

Cited by 95 publications

(55 citation statements)

References 39 publications

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“…The possibility to achieve MILD combustion conditions with different gaseous fuels has been extensively investigated in the literature [3][4][5][6][7][8][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] . However, the same is not true for the MILD combustion of liquid fuels, for which much less information are available, as recently reviewed by Xing et al 31 .…”

Section: Introductionmentioning

confidence: 99%

110th Anniversary: MILD Combustion of Liquid Hydrocarbon–Alcohol Blends

Derudi

Rota

2019

Ind. Eng. Chem. Res.

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Among the various low NOx combustion technologies, MILD combustion combines low pollutant emissions, combustion stability and efficiency, fuel flexibility, and noise reduction through a high preheating of the combustion chamber coupled with a massive exhaust gas recirculation at high turbulence level. In this work, the sustainability of MILD combustion for liquid hydrocarbon-alcohol blends (as possible constituents of surrogate fuels representing the behavior of blends of fossil fuels and biofuels) has been investigated experimentally using a dual-nozzle laboratory-scale burner. Several hydrocarbon-alcohol blends have been investigated to identify the regions (in the furnace temperature vs. dilution ratio space) where MILD combustion can be sustained with low NOx and CO emissions. It has been found that the MILD combustion conditions of the various liquid fuel blends investigated differ slightly one to each other and are quite similar to that of the hydrocarbons without any oxygenated species. This means that a MILD combustion burner shows a large flexibility in terms of fuel properties, therefore creating a suitable environment for NOx and CO depression also for fossil fuels-biofuels blends.

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Section: Introductionmentioning

confidence: 99%

110th Anniversary: MILD Combustion of Liquid Hydrocarbon–Alcohol Blends

Derudi

Rota

2019

Ind. Eng. Chem. Res.

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“…In this case, heated gas is required as a carrier to help deliver prevaporised ethanol and prevent it from condensing. The choice of carrier gas, such as air or N 2 , has been reported to affect the temperature distribution and the flame structure in spray burners [18,19], and change the NO x formation in a reverse-flow MILD combustor [20]. In addition, previous work [21] has shown that the enhanced O 2 diffusion towards the fuel-rich side through "reaction zone weakening" is a key feature of MILD combustion flames, leading to an increasing formation of important intermediates.…”

Section: Introductionmentioning

confidence: 99%

The transition of ethanol flames from conventional to MILD combustion

Medwell

Dally

et al. 2016

Combustion and Flame

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The present paper is focused on prevaporised ethanol flames in the transition from conventional combustion to the MILD combustion regime. Photographs and imaging of OH * chemiluminescence reveal a distinctive flame structure when ethanol carried by air burns in a 3% O 2 coflow (typical of MILD combustion), differing from that at higher oxygen levels. In comparison to flames carried by air in a 9% O 2 coflow, the spatial gradient and the peak in the OH * signal profile are significantly reduced in the 3% O 2 coflow, indicating a more uniform distribution of heat release and temperature. The use of N 2 as a carrier gas renders the OH * profile for the 6% O 2 coflow case similar to that of flames carried by air in the 3% O 2 coflow. The experimental results indicate a transition from conventional combustion to MILD combustion with the decrease of coflow O 2 level and/or the use of N 2 as a carrier gas. Calculations reveal that a substantial drop in the peak heat release rate and/or overall net heat release rate might contribute to the lack of luminosity of flames in the 3% O 2 coflow, suggesting a need for threshold values of these two in defining MILD combustion. A series of laminar flame calculations are performed to identify the MILD combustion regime based on the absence of a negative heat release region. The absence of a negative heat release region is found to be strain rate dependent at a given temperature and O 2 level of the oxidant stream. This is mainly a result of the enhanced transportation of O 2 across the reaction zone at a higher strain rate. At low strain rates, the negative heat release region is more likely to disappear in a 3% O 2 oxidant flow due to a combination of low flame temperature and high availability of O 2 .

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“…As a result, this will allow the liquid fuel to silt at the bottom of the rig, thus reducing the efficiency of the process, and obstructing the production of flameless mode. Thus, a much more complex mixing method that involves atomization and vaporization of liquid fuel through jet spray is needed to produce a relatively homogenous mixture for combustion process [20,23,24].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Multiple Swirl Generator Inlets Circumferential Distribution to a Liquid Fuelled Ultra-High Swirl Flameless Combustion Characteristics

Kasani

Wahid

Ghazali

et al. 2020

ARFMTS

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This paper presents the experimental results of a simple cylindrical shaped, liquid fuelled flameless combustor which utilizes ultra-high swirl flow in the combustion process. 4 different swirl generator inlet configurations were tested in this work. Ethanol fuel were used during flameless mode. The experiments were conducted at equivalence ratio (F=1), with the flow rate of fuel set at 4.48*104 kg/s, and flow rate of air at 3.854*103 kg/s. The results revealed that by using all 12 tangential air inlets (swirl generator injectors), the swirl strength was reduced through evenly distributing the position of the injectors circumferentially. As a result, the combustor successfully suppressed the emission of NOx and CO to zero ppm for both gasses. It was also reported that flameless mode was established in all configurations, regardless of the swirl strength.

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An experimental study on MILD combustion of prevaporised liquid fuels

Cited by 95 publications

References 39 publications

110th Anniversary: MILD Combustion of Liquid Hydrocarbon–Alcohol Blends

110th Anniversary: MILD Combustion of Liquid Hydrocarbon–Alcohol Blends

The transition of ethanol flames from conventional to MILD combustion

The Effects of Multiple Swirl Generator Inlets Circumferential Distribution to a Liquid Fuelled Ultra-High Swirl Flameless Combustion Characteristics

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