scholarly journals Electric Field Effect on the Thermal Decomposition and Co-combustion of Straw with Solid Fuel Pellets

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1522 ◽  
Author(s):  
Inesa Barmina ◽  
Antons Kolmickovs ◽  
Raimonds Valdmanis ◽  
Maija Zake ◽  
Sergejs Vostrikovs ◽  
...  
Keyword(s):  
Electric Field ◽  
Solid Fuel ◽  
Flame Temperature ◽  
Fixed Bed ◽  
Chemical Conversion ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Heat Output ◽  
Electric Field Effect ◽  
Fuel Mixtures

The aim of this study was to provide more effective use of straw for energy production by co-firing wheat straw pellets with solid fuels (wood, peat pellets) under additional electric control of the combustion characteristics at thermo-chemical conversion of fuel mixtures. Effects of the DC electric field on the main combustion characteristics were studied experimentally using a fixed-bed experimental setup with a heat output up to 4 kW. An axisymmetric electric field was applied to the flame base between the positively charged electrode and the grounded wall of the combustion chamber. The experimental study includes local measurements of the composition of the gasification gas, flame temperature, heat output, combustion efficiency and of the composition of the flue gas considering the variation of the bias voltage of the electrode. A mathematical model of the field-induced thermo-chemical conversion of combustible volatiles has been built using MATLAB. The results confirm that the electric field-induced processes of heat and mass transfer allow to control and improve the main combustion characteristics thus enhancing the fuel burnout and increasing the heat output from the device up to 14% and the produced heat per mass of burned solid fuel up to 7%.

scholarly journals Electric Field Control of the Polluting Emissions from a Propane Flame

2013 ◽  
Vol 3 (2) ◽  
pp. 95-108
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Heat Mass Transfer ◽  
Carbon Capture ◽  
Flame Temperature ◽  
Fuel Combustion ◽  
Electric Field Effect ◽  
Electric Field Effects ◽  
Field Effects ◽  
Polluting Emissions

The present study is performed with the aim to reduce the levels of polluting emissions from fuel combustion that produce acid rains and the greenhouse effect (NOx, CO2). The electric field effects on the processes of heat/mass transfer and propane combustion are studied in order to perform electric control of the levels of polluting emissions from the flame. The results of experimental studies show the direct influence of the electric field's enhanced mass transfer on local variations of the flame composition and fuel combustion. The related variations of the flame temperature, processes of soot formation, carbon capture and deposition along the flame channel flow are studied by varying the field strength and the equivalence ratio of the propane-air mixture. The results show that the electric field effect on soot for- mation, carbon capture and sequestration, for fuel-rich flame flow, can be used to reduce the levels of CO2 emissions from the flame. In addition, the field-enhanced heat/ mass transfer to the channel walls, for fuel-lean conditions, can be used to control the fuel combustion, flame temperature and temperature- sensitive levels of NOx emissions. The most pronounced electric field effects on fuel combustion and composition of the products are observed in the limit of the weak fields (U<1,2 kV, E<105 V m-1).

Study of Combustion Characteristics of Ethanol at Different Dilution With the Carrier Gas

2014 ◽  
Author(s):  
Binash Imteyaz ◽  
Mohamed A. Habib
Keyword(s):  
Carbon Dioxide ◽  
Flue Gas ◽  
Carbon Capture ◽  
Liquid Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Conventional Combustion ◽  
Gas Volume

With the ever rising concern of global warming, carbon capture is gaining the reputation of one of the most challenging fields of research. A very promising technology to capture CO2 is oxy-combustion. Oxy-combustion offers several advantages over conventional combustion technologies, such as flue gas volume reduction, high combustion efficiency, low fuel consumption and significant reduction in NOx emissions. Liquid fuel is available and it is the most widely used source of energy in the world. Easy handling and transportation, less storage volume and higher flame temperature are some of the features of liquid fuel which give it an upper hand over other sources. In this study, an experimental work on oxygen enriched combustion of ethanol in a vertical reactor by Lacas F. et. al. has been modeled numerically. Non-premixed model using Probability Density Function has been incorporated to simulate the combustion process of ethanol droplets. Predicted combustion characteristics are found to be in good compliance with the experimental data. In addition to this, effects of dilution of carbon-dioxide in oxygen on the flame properties have also been presented. Combustion of ethanol in oxygen-carbon dioxide environment has been compared with that of the conventional air environment.

Study of Combustion Characteristics of Ethanol at Different Dilution With the Carrier Gas

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Binash Imteyaz ◽  
Mohamed A. Habib
Keyword(s):  
Carbon Dioxide ◽  
Flue Gas ◽  
Carbon Capture ◽  
Liquid Fuel ◽  
Flame Temperature ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Gas Volume ◽  
Probability Density Function Pdf

With the ever-rising concern of global warming, carbon capture is gaining the reputation of one of the most challenging fields of research. A very promising technology to capture CO2 is oxy-combustion. Oxy-combustion offers several advantages over conventional combustion technologies, such as flue–gas volume reduction, high combustion efficiency, low fuel consumption, and significant reduction in NOx emissions. Liquid fuel is available and it is the most widely used source of energy in the world. Easy handling and transporting, less storage volume and higher flame temperature are some of the features of liquid fuel which give it an upper hand over other sources. In this study, an experimental work on oxygen enriched combustion of ethanol in a vertical reactor by Lacas et al. (2005, “Experimental Study of Air Dilution in Oxy-Liquid Fuel Flames,” Proc. Combust. Inst., 30(2), pp. 2037–2045) has been modeled numerically. Nonpremixed model using probability density function (PDF) has been incorporated to simulate the combustion process of ethanol droplets. Predicted combustion characteristics are found to be in good compliance with the experimental data. In addition to this, effects of dilution of carbon dioxide in oxygen on the flame properties have also been presented. Combustion of ethanol in oxygen–carbon dioxide environment has been compared with that of the conventional air environment.

scholarly journals Electric field control of NOx formation in the flame channel flows

2013 ◽  
Vol 2 (1) ◽  
pp. 99-108
Keyword(s):  
Electric Field ◽  
Flame Temperature ◽  
Radial Electric Field ◽  
Fuel Combustion ◽  
Channel Flows ◽  
Electric Field Effect ◽  
Radical Ions ◽  
Nox Formation ◽  
Drift Motion ◽  
Thermal Nox

The present studies aimed to obtain clean fuel combustion and get detailed information about the processes that determine the electric field effect on NOx formation in flame channel flows. The experimental studies demonstrate that the interaction between the radial electric field and the flame initiates the field-forced drift motion of positive radical ions in a field direction. The energy exchange between ions and gas particles produces interrelated heat and mass transfer to the negatively biased channel walls. Hence, by varying the applied voltage, a field-enhanced reducing of a flame temperature is obtained, thereby lowering thermal NOx formation during the fuel combustion up to 30-80%.

scholarly journals Thermal Decomposition and Combustion of Microwave Pre-Treated Biomass Pellets

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 492
Author(s):  
Linards Goldšteins ◽  
Raimonds Valdmanis ◽  
Maija Zaķe ◽  
Alexandr Arshanitsa ◽  
Anna Andersone
Keyword(s):  
Thermal Decomposition ◽  
Wheat Straw ◽  
Elemental Composition ◽  
Heat Production ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Heat Output ◽  
Structural Variations ◽  
Microwave Pretreatment ◽  
Pretreated Wheat Straw

The objective of the study was to investigate a more effective use of commercially available biomass pellets (wheat straw, wood, peat) using microwave pretreatment to improve heat production. Pellets were pretreated using the originally designed microwave torrefaction device. The effects of microwave (mw) pretreatment were quantified, providing measurements of the weight loss and elemental composition of pellets and estimating the effect of mw pretreatment on their porosity, surface area and calorific values at pretreatment temperatures of T = 448–553 K. Obtained results show that the highest structural variations and elemental composition during mw pretreatment were obtained for wheat straw pellets, with an increase in reactivity, a decreasing in the duration of the thermal decomposition by about 40% and an increase in the yield of combustible volatiles. Increased reactivity of pretreated pellets enhanced the ignition and burnout of volatiles, decreasing the duration of the burnout of pretreated wheat straw, wood and peat pellets by 40%, 24% and 9%, respectively, and increasing the peak and average values of the flame temperature, heat output, and produced heat energy by 40–50%, with a correlating increase of combustion efficiency and the mass fraction of carbon-neutral CO2 emission. Thus, the applicability of microwave pretreatment for the control and improvement of heat production was confirmed.

An Experimental Study of Optimum Angle of Air Swirler Vanes in Liquid Fuel Burners

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
S. H. Pourhoseini ◽  
Rasoul Asadi
Keyword(s):  
Heat Flux ◽  
Flame Temperature ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Heat Flux Sensor ◽  
Radiation Heat ◽  
Radiation Heat Flux ◽  
Optimum Angle ◽  
Pollutants Emission ◽  
Temperature Radiation

The present work shows that how the angle of an air swirler vane affects the combustion characteristics of liquid fuels such as flame temperature, radiation heat flux, combustion efficiency, and pollutants' emission. It finds out an optimum angle of vane based on flame characteristics. Three vanes with angles of 0 deg, 40 deg, and 80 deg which induced low and high-swirl intensities in air stream were investigated, and the combustion characteristics of flame were quantified. The flame temperature was measured by an S-type thermocouple, and a Testo 350 XL gas analyzer was used to determine the CO and NO pollutant concentrations. Also, gravity method was used to gauge the soot concentration along the furnace, and a SBG01 water cooled heat flux sensor determined the flame radiation. The results indicate that the angle of the swirler vane has significant effects on temperature, combustion efficiency, and NO and CO pollutants' emission. Most importantly, there is an optimum angle for the swirler vane. At the optimum angle, the optimum combination of the contact area and time maximizes the mixing rate of the inlet air and the fuel jet. Consequently, at the optimum angle, the mean temperature, radiation heat flux, and combustion efficiency are higher than at small and large swirl angles and soot, CO and NOx emissions are at their minimum states.

scholarly journals The Effect of Electric Field Configuration on the Thermo-Chemical Conversion of Straw Pellets

2020 ◽  
Vol 57 (4) ◽  
pp. 65-76
Author(s):  
I. Barmina ◽  
A. Kolmickovs ◽  
R. Valdmanis ◽  
S. Vostrikovs ◽  
M. Zake
Keyword(s):  
Electric Field ◽  
Energy Production ◽  
Chemical Conversion ◽  
Field Configuration ◽  
Heat Energy ◽  
Ion Current ◽  
Experimental Investigations ◽  
Electric Field Effect ◽  
Combustion Dynamics ◽  
Dc Electric Field

AbstractWith the aim to control and improve the thermo-chemical conversion of straw pellets, the experimental investigations of the DC electric field effect on the combustion dynamics and heat energy production were made. The electric field effect on the gasification/combustion characteristics was studied using three different positions of the positively charged electrode in flame. First, the electrode was positioned coaxially downstream the flame flow. Next, the electrode was positioned coaxially upstream the flame flow and, finally, the electrode was positioned across the downstream flow. The bias voltage of the electrode varied in the range from 0.6 up to 1.8 kV, while the ion current in flame was limited to 5 mA. The results of experimental investigations show that the DC electric field intensifies the thermal decomposition of straw pellets and enhances mixing of volatiles with air causing changes in combustion dynamics and heat energy production, which depend on position and the bias voltage of the electrode. The increase in the average volume fraction of CO2 (by 6 %) and the decrease in the mass fraction of unburned volatiles in the products (CO by 60 % and H2 by 73 %) for the upstream field configuration of the electrode and the ion current 0.5–1.8 mA indicate more complete combustion of volatiles.

Pollutant emission from a heat station supplied with agriculture biomass and wood pellet mixture

2012 ◽  
Vol 33 (2) ◽  
pp. 231-242 ◽  
Author(s):  
Marek Juszczak ◽  
Katarzyna Lossy
Keyword(s):  
Carbon Monoxide ◽  
Pollutant Emission ◽  
Heat Output ◽  
Wood Pellets ◽  
Wood Pellet ◽  
Carbon Monoxide Concentration ◽  
Heat Efficiency ◽  
Air Stream ◽  
Fuel Mixtures ◽  
Lower Carbon

Pollutant emission from a heat station supplied with agriculture biomass and wood pellet mixtureTests for combustion of hay and sunflower husk pellets mixed with wood pellets were performed in a horizontal-feed as well as under-feed (retort) wood pellet furnace installed in boilers with a nominal heat output of 15 and 20 kW, located in a heat station. During the combustion a slagging phenomenon was observed in the furnaces. In order to lower the temperature in the furnace, fuel feeding rate was reduced with unaltered air stream rate. The higher the proportion of wood pellets in the mixture the lower carbon monoxide concentration. The following results of carbon monoxide concentration (in mg/m3presented for 10% O2content in flue gas) for different furnaces and fuel mixtures (proportion in wt%) were obtained: horizontal-feed furnace supplied with hay/wood: 0/100 - 326; 30/70 - 157; 50/50 - 301; 100/0 - 3300; horizontal-feed furnace supplied with sunflower husk/wood: 50/50 - 1062; 67/33 - 1721; 100/0 - 3775; under-feed (retort) furnace supplied with hay/wood: 0/100 - 90; 15/85 - 157; 30/70 - 135; 50/50 - 5179; under-feed furnace supplied with sunflower husk/wood: 67/33 - 2498; 100/0 - 3128. Boiler heat output and heat efficiency was low: 7 to 13 kW and about 55%, respectively, for the boiler with horizontal-feed furnace and 9 to 14 kW and 64%, respectively, for the boiler with under-feed furnace.

EFFECT OF MOISTURE AND PARTICLE SIZE ON THE COMBUSTION CHARACTERISTICS OF SEWAGE SLUDGE IN A FIXED BED

2018 ◽  
Author(s):  
Joana Freitas Campana ◽  
Kaio Pandolfi Pessotti ◽  
Carlos Eduardo Silva Abreu ◽  
Patrick de Jesus
Keyword(s):  
Particle Size ◽  
Sewage Sludge ◽  
Fixed Bed ◽  
Combustion Characteristics ◽  
Effect Of Moisture
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