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.

DC-electric-field effect on CdSe nanocrystal embedded in Indium tin oxide film and its second-order nonlinearity

2001 ◽  
Vol 44 (8-9) ◽  
pp. 1219-1223 ◽  
Author(s):  
Aiko Narazaki ◽  
Toshiaki Hirano ◽  
Jun Sasai ◽  
Katsuhisa Tanaka ◽  
Kazuyuki Hirao ◽  
...  
Keyword(s):  
Oxide Film ◽  
Electric Field ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Field Effect ◽  
Second Order ◽  
Electric Field Effect ◽  
Dc Electric Field ◽  
Second Order Nonlinearity

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 MATHEMATICAL MODELLING AND EXPERIMENTAL STUDY OF STRAW CO-FIRING WITH GAS

2019 ◽  
Vol 24 (4) ◽  
pp. 507-529
Author(s):  
Inesa Barmina ◽  
Harijs Kalis ◽  
Antons Kolmickovs ◽  
Maksims Marinaki ◽  
Liiva Ozola ◽  
...  
Keyword(s):  
Experimental Study ◽  
Thermal Decomposition ◽  
Mathematical Modelling ◽  
Wheat Straw ◽  
Energy Production ◽  
Heat Energy ◽  
Combustion Characteristics ◽  
Combustion Dynamics ◽  
Additional Heat ◽  
Ignition And Combustion

The main goal of the present study is to promote a more effective use of agriculture residues (straw) as an alternative renewable fuel for cleaner energy production with reduced greenhouse gas emissions. With the aim to improve the main combustion characteristics at thermo-chemical conversion of wheat straw, complex experimental study and mathematical modelling of the processes developing when co-firing wheat straw pellets with a gaseous fuel were carried out. The effect of co-firing on the main gasification and combustion characteristics was studied experimentally by varying the propane supply and additional heat input into the pilot device, along with the estimation of the effect of co-firing on the thermal decomposition of wheat straw pellets, on the formation, ignition and combustion of volatiles (CO, H2). A mathematical model has been developed using the environment of the Matlab (2D modelling) and MATLAB package ”pdepe”(1D modelling) considering the variations in supplying heat energy and combustible volatiles (CO, H2) into the bottom of the combustor. Dominant exothermal chemical reactions were used to evaluate the effect of co-firing on the main combustion characteristics and composition of the products CO2 and H2O. The results prove that the additional heat from the propane flame makes it possible to control the thermal decomposition of straw pellets, the formation, ignition and combustion of volatiles and the development of combustion dynamics, thus completing the combustion of biomass and leading to cleaner heat energy production.

scholarly journals Experimental investigations of ion current in liquid-fuelled gas turbine combustors

2017 ◽  
Vol 9 (3) ◽  
pp. 172-185 ◽  
Author(s):  
J Christopher Wollgarten ◽  
Nikolaos Zarzalis ◽  
Fabio Turrini ◽  
Antonio Peschiulli
Keyword(s):  
Feedback Control ◽  
Vortex Core ◽  
Ion Current ◽  
Injection System ◽  
Experimental Investigations ◽  
Control Loop ◽  
Combustion Dynamics ◽  
Lean Blowout ◽  
Precessing Vortex Core ◽  
Interaction Mode

This work covers investigations of the static and dynamic behaviour of a confined, co-swirled and liquid-fuelled airblast injection system. The focus lies on the application of ion current sensors for the qualitative measurement of the heat release rate or for flame monitoring purposes in complex technical combustion processes. The ion current sensor is to operate in a feedback control loop in order to react on combustion dynamics in real time. The first part of the work analyses experimental data, which were obtained with different techniques, e.g. dynamic pressure, chemiluminescence, fine-wire thermocouples and ion current. The results show that the thermo-acoustic instability and the precessing vortex core generate an interaction mode. The frequency of this interaction mode is the difference of the other two modes. This has not yet been observed for partially premixed and liquid-fuelled injection systems before and also was not detected by the chemiluminescence of the flame. The ion current measurement technique is able to detect the helical mode of the precessing vortex core as well as the interaction frequency, leading to the conclusion that the chemical reactions are influenced by this helical structure. Contour maps of the frequencies reveal this influence in the outer shear layer. The second part of the study focused on the ion current probe as a method to predict static combustion instabilities, such as lean blowout. According to the results, the ion current is a fast responding method to detect lean blowout, provided that the detector is mounted at a suitable position. Measurements at different positions in the flame were compared with phase-locked chemiluminescence measurements. Precursors in the ion current signal for lean-blowout prediction were found using a statistical approach, which is based on ion peak distance. The precursor events allow for the use of this approach with a feedback control loop in future applications.

dc electric field effect on the microwave properties of YBa2Cu3O7/SrTiO3layered structures

1994 ◽  
Vol 76 (5) ◽  
pp. 2937-2950 ◽  
Author(s):  
A. T. Findikoglu ◽  
C. Doughty ◽  
S. M. Anlage ◽  
Qi Li ◽  
X. X. Xi ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Effect ◽  
Microwave Properties ◽  
Electric Field Effect ◽  
Dc Electric Field
Sign in / Sign up

Export Citation Format

Share Document