ELECTRODYNAMIC CONTROL OF STRAW CO-FIRING WITH PROPANE

The recent research focuses on the experimental study of the electric field effects on the combustion dynamics during co-firing of straw pellets and propane with the aim to provide control of the thermal decomposition of straw and combustion conditions of combustible volatiles to ensure wider use of straw as fuel for energy production. The experimental studies were carried out using a pilot setup TRL-4. This pilot setup is composed of a gasifier, combustor and a propane burner for co-firing of straw. The electric field was applied to the flame base using the axially inserted electrode with positive bias voltage relative to the grounded walls of the combustor. To assess the electric field effects on the development of gasification/combustion during co-firing of straw with propane, complex measurements of the main gasification/combustion characteristics were carried out by varying the bias voltage of the axially inserted electrode and by limiting the electric current to 7 mA. Kinetic study of the weight loss rate of straw and the composition of volatiles let to conclude that the general trend of the electric field effect on the processes developing during the thermal decomposition/gasification of straw is an enhancement of the formation of combustible volatiles (CO and H-2) with an improvement of the combustion conditions in the flame reaction zone. The improvement of the combustion conditions results in an increase of the heat output from the reaction zone was by about 10 % and the heat energy produced per mass of burned straw pellets by about 13 %. In addition, the mass fraction of CO decreases by about 35 % with correlating increase of the CO2 volume fraction in the products. The mechanism of the electric field effects on thermal decomposition of straw and combustion characteristics during co-firing of straw with propane is discussed with account of the thermal and chemical interaction between the components and field-induced ion wind, and the Lorentz force effects on the flame.