Combustion Characteristics of Biofuels in Porous-Media Burners at an Equivalence Ratio of 0.8

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Pablo E. Barajas ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Porous Media ◽  
Methyl Ester ◽  
Particle Deposition ◽  
Equivalence Ratio ◽  
Combustion Characteristics ◽  
Axial Temperature ◽  
Alternative Sources ◽  
Soy Methyl Ester ◽  
Interior Walls ◽  
Porous Media Burner

Biofuels, such as canola methyl ester (CME) and soy-methyl ester (SME) derived from vegetable oil, are alternative sources of energy that have been developed to reduce the dependence on petroleum-based fuels. In the present study, CME, SME, and commercial Jet-A fuel were tested in a porous-media burner at an equivalence ratio of 0.8 at the burner entrance. The measured combustion characteristics included NOx and CO emission indices, radiative fraction of heat release, and axial temperature profile in the surface stabilized and extended flame. The effects of fuel on the injector and porous-media durability were also documented. The NOx emission index was higher for the SME and CME flames than that of the Jet-A flame. Furthermore, the axial temperature profiles were similar for all the flames. The prolonged use of CME and SME resulted in more solid-particle deposition on the interior walls of the injector and within the structure of the porous medium than for Jet-A fuel, thereby increasing the restriction to the fuel/air flow and pressure drop across the burner.

Experimental Investigation of Porous-Media Combustion Characteristics of Biodiesel Blends

2010 ◽  
Author(s):  
Balasaheb S. Dahifale ◽  
Ramkumar N. Parthasarathy ◽  
Subramanyam R. Gollahalli
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Pore Size ◽  
Equivalence Ratio ◽  
Energy Resource ◽  
Combustion Characteristics ◽  
Pollutant Emissions ◽  
Pollutant Emission ◽  
Porous Media Burner ◽  
Emission Index

The use of porous-media burners in air-heating systems, gas turbine combustors, and steam generators is a potential method to reduce pollutant emission levels. Biofuels, such as canola methyl ester (CME), are an attractive alternate energy resource; however, pure biofuels have lower energy content than petroleum-based fuels. Therefore, the combustion characteristics of blends of Jet A and CME were studied in a porous-media burner. Two silicon carbide coated carbon-carbon matrix porous media of square section were used. The upstream porous medium with a pore size of 8 pores per centimeter (20 pores per inch) served as the evaporation porous medium; the downstream porous medium with a pore size of 31 ppcm (80 ppi) was used as the combustion porous medium. The CME-Jet A fuel blends were injected from an air-blast atomizer into a coflow of hot air, which entered the evaporation porous medium. The combustion characteristics of three blends (volume percentages of CME equal to 25%, 50% and 75%) were studied at four different initial equivalence ratios. The global pollutant emissions, axial temperature profiles and the radiative heat fraction of the flame downstream of the combustion porous medium were measured. The results indicated that for lean air-fuel mixtures, the addition of CME to Jet A resulted in a reduction of the CO emission index. However, the NOx emission index was increased with the CME content in the blend for a given equivalence ratio. Also, the maximum flame temperature increased with equivalence ratio. In general, it was found that the porous-media burner was useful in reducing emissions and controlling flame temperatures.

Combustion characteristics of blast furnace gas in porous media burner

2019 ◽  
Vol 160 ◽  
pp. 113970 ◽  
Author(s):  
Jinqiao He ◽  
Zhengchun Chen ◽  
Xin Jiang ◽  
Chun Leng
Keyword(s):  
Porous Media ◽  
Blast Furnace ◽  
Combustion Characteristics ◽  
Blast Furnace Gas ◽  
Porous Media Burner

Numerical Investigation on Performance of a Porous Medium Burner with Reciprocating Flow

2013 ◽  
Vol 781-784 ◽  
pp. 2741-2744
Author(s):  
Jun Rui Shi ◽  
Zhi Peng Wu ◽  
Yang Yang ◽  
Zhi Jia Xue ◽  
Xiu Li Zhang
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Equivalence Ratio ◽  
Moderate Pressure ◽  
Two Dimensional ◽  
Numerical Investigations ◽  
Structure Improvement ◽  
Burner Design ◽  
Porous Media Burner ◽  
Reciprocating Flow

Two-dimensional numerical investigations on the performance and structure improvement of a inert porous media burner with reciprocating flow are presented. An improved burner design is proposed and this leads to a wider high temperature profile and moderate pressure loss for extremely dilute CH4/air mixture with an equivalence ratio of 0.1.

Numerical Study on the Premixed Combustion in Porous Media Burner

2012 ◽  
Vol 614-615 ◽  
pp. 73-76 ◽  
Author(s):  
Jin Yan Zhang ◽  
Hong Sheng Liu ◽  
Zhen Jie Xu
Keyword(s):  
Porous Media ◽  
Equivalence Ratio ◽  
Numerical Study ◽  
Gaseous Mixture ◽  
Packed Bed ◽  
Discrete Ordinates ◽  
Gas Mixture ◽  
Inlet Velocity ◽  
Fluent Software ◽  
Porous Media Burner

The phenomenon of combustion of a gaseous mixture in a two-dimension alumina ( ) particle packed bed porous media burner is studied by means of a numerical simulation with FLUENT software using two-step reaction mechanism. The Eddy-dissipation-concept (EDC) model, the standard model and the Discrete- Ordinates (DO) radiation model are used in this paper. It is concluded that the methane/air gas mixture with lower equivalence ratio or with faster inlet velocity, can achieve the faster wave propagates. The methane/air gas mixture with lower equivalence ratio or with faster inlet velocity, can achieve the faster wave propagates.

scholarly journals Entropy Generation and Exergy Analysis of Premixed Fuel-Air Combustion in Micro Porous Media Burner

Entropy ◽  
2020 ◽  
Vol 22 (10) ◽  
pp. 1104
Author(s):  
N. C. Ismail ◽  
M. Z. Abdullah ◽  
N. M. Mazlan ◽  
K. F. Mustafa
Keyword(s):  
Porous Media ◽  
Double Layer ◽  
Entropy Generation ◽  
Equivalence Ratio ◽  
Single Layer ◽  
Exergy Efficiency ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Total Entropy ◽  
Porous Media Burner

The performance of porous media micro-burners plays an important role in determining thermal efficiency and improving our daily life. Nowadays, a lot of scholars are actively involved in this research area and ongoing studies are still being carried out due to the burners’ excellent performance. The exergy efficiency and entropy generation of a porous media burner are strongly dependent on the characteristics of the flame and its thermal behavior. In this study, a single-layer and double-layer porous media form were constructed to investigate the effects of various types of porous foam arrangement in a cylindrical burner. The burner was operated using premixed butane-air combustion with an inner diameter of 23 mm and a length of 100 mm. The experiments were carried out in rich fuel conditions with an equivalence ratio, φ ranging from 1.3 to 2.0. The results showed significant improvement in the thermal and exergy efficiency with an increase in the equivalence ratio in a double-layer compared with a single-layer. The peak temperature recorded was 945.21 °C at φ = 1.3 for a porcelain single-layer, and the highest exergy efficiency was 83.47% at φ = 2.0 for an alumina-porcelain double-layer burner. It was also found that the average temperature of the burner wall decreased with an increase in the equivalence ratios for PMB2 and PMB4, whereas the average wall temperature for PMB3 was largely unaffected by the equivalence ratios. The total entropy generation rate reached the highest value at φ = 2.0 for all PMB configurations, and the highest percentage increase for total entropy generation rate was 46.09% for PMB1. The exergy efficiency for all burners was approximately similar with the highest exergy efficiency achieved by PMB4 (17.65%). In addition, the length and location of the flame with thermal distribution was significantly affected by the equivalence ratio between the single-layer and double-layer porous material. Overall, a double-layer porous media burner showed the best performance calculated based on the second law of thermodynamics when compared with other configurations, and it is ideal for domestic application.

Combustion Characteristics of Partially Premixed Prevaporized Palm Methyl Ester and Jet A Fuel Blends

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
A. Balakrishnan ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Methyl Ester ◽  
Equivalence Ratio ◽  
Volume Concentration ◽  
Laminar Flame ◽  
Combustion Characteristics ◽  
Phase Reaction ◽  
No Emission ◽  
Combustion Properties ◽  
Emission Index ◽  
Palm Methyl Ester

Palm methyl ester (PME) is an attractive alternate biofuel produced by the transesterification of palm oil with methanol. This paper is a sequel to our earlier papers on the comparison of the flame structure and emission characteristics of neat PME with those of petroleum-derived fuels (No. 2 diesel and neat Jet A). Blends of prevaporized Jet A fuel and PME (25%, 50%, and 75% by volume) were studied in a laminar flame environment at burner-exit equivalence ratios of 2, 3, and 7. The global combustion characteristics including flame length, CO and NO emission indices, radiative heat fraction, and in-flame profiles of species concentration (CO, CO2, NO, and O2), temperature, and soot volume concentration were measured. The global CO emission index decreased significantly with the PME content in the blend at an equivalence ratio of 7; a 30% reduction was observed with the addition of 25% PME by volume, and a further reduction of 25% was observed with the addition of another 25% PME. The global NO emission index of the neat PME flame was 35% lower than that of the Jet A flame at an equivalence ratio of 2. The near-burner homogeneous gas-phase reaction zone increased in length with the addition of PME at all equivalence ratios. The concentration measurements highlighted the nonmonotonic variation of properties with the volume concentration of PME in the fuel blend. The fuel-bound oxygen and hydrogen of PME affected the combustion properties significantly.

Measuring Ignition Temperature and the Rate of Energy Generation From Canola Methyl Ester and Soy Methyl Ester in Oxygen-Nitrogen Mixtures on Platinum-Rhodium

2011 ◽  
Author(s):  
Bradley McGary ◽  
Judi Steciak ◽  
Ralph Budwig ◽  
Steve Beyerlein
Keyword(s):  
Methyl Ester ◽  
Ignition Temperature ◽  
Equivalence Ratio ◽  
Flow Reactor ◽  
Volume Fraction ◽  
Surface Reactions ◽  
Energy Generation ◽  
Fuel Vapor ◽  
Vapor Flow ◽  
Soy Methyl Ester

A heated plug flow reactor was used to study the reactions of nonflammable mixtures of canola methyl ester-oxygen and soybean methyl ester-oxygen diluted with nitrogen over a coiled 90%:10% platinum:rhodium wire catalyst. The temperature the catalyst needed to reach to initiate surface reactions (ignition temperature) and the subsequent rate of energy generation were determined. The absolute volume fraction of fuel was varied from 0.238% to 0.445% and the relative fuel-oxygen equivalence ratio, φ, was varied between 0.4 and 1.0. The 127 micrometer diameter Pt-Rh wire was coiled and suspended crosswise in the quartz tube of the reactor. Evaporated biodiesel was delivered by heated nitrogen into the apparatus and blended with oxygen in a mixing nozzle. The wire catalyst was electrically heated and acted as a resistance thermometer to measure its average temperature. Ignition temperatures increased with increasing equivalence ratio and volumetric fuel vapor percentage, thus indicating initial fuel coverage of the catalyst surface. Temperatures as low as 912 K at φ = 0.4 for 0.268% Soy Methyl Ester (SME) and as high as 991 K at φ = 1.0 for 0.445% Canola Methyl Ester (CME) were recorded. The rate of energy generated due to surface reactions for both biodiesels decreased with increasing equivalence ratio and generated less energy as fuel percentages decreased. The lowest and highest rates of energy generation were both obtained from experiments with CME with 6.9 W/cm2 at φ = 1 for 0.268% fuel and 25.3 W/cm2 at φ = 0.4 for 0.445% fuel. The extremes of the rate of heat generated from SME reactions were 5.1 W/cm2 and 28.6 W/cm2, both at φ = 0.4, with 0.238% and 0.417% fuel, respectively. Another outcome of this work was achieving steady evaporation of microliter/hour heavy fuel vapor flow rates. This was aided by thermogravimetric analysis (TGA) to determine thin-film vaporization temperatures. CME and SME had the lowest evaporation temperatures of 188 K and 186 K, respectively.

Numerical investigation of the flame stabilization in a divergent porous media burner

2017 ◽  
Vol 231 (3) ◽  
pp. 173-181 ◽  
Author(s):  
Seyed Mohammad Hashemi ◽  
Seyed Abdolmehdi Hashemi
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Equivalence Ratio ◽  
Flame Stabilization ◽  
Heat Transfer Analysis ◽  
Divergence Angle ◽  
Flame Stability ◽  
Gas Temperature ◽  
Heat Recirculation ◽  
Porous Media Burner

In the present work, a numerical study on the flame stabilization in a divergent porous media burner was carried out. The purpose of this study was to peruse the influence of different conditions on the flame status in a porous medium. Two-dimensional axisymmetric model was used to simulate the process of premixed methane–air combustion. Nonequilibrium condition between the solid and gas temperature was considered and heat recirculation in the porous medium was quantified. The present numerical method was validated by comparison of solid and gas temperature profiles against the experimental data. The results showed that the stable flame within the porous medium can be controlled by velocity and equivalence ratio of the incoming mixture. Also, it was proved that the alteration of divergence angle can change the flame stability limit so that the optimum divergence angle that results in the highest limit of flame stability range was 60°. The heat transfer analysis indicated that the heat recirculation efficiency decreases with increase in the equivalence ratio and inlet velocity.

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